Powders Characterizations – GAT Scientific

Saturn DigiSizer II

gatscadmin — Wed, 06 May 2020 04:55:11 +0000

Particle sizing techniques have advanced significantly throughout the past several decades. One of the most important contributions to this field is the application of laser-based technologies, complemented with the use of modern photo-detectors and digital computers. For some time, progress in laser light scattering technology has led to faster analyses, but the quality of the measurement was limited, often due to inadequacies in the detector.

Recognizing this need for better detection capability, Micromeritics developed the Saturn DigiSizer, an instrument that employed a laser diode and modern charge-coupled device (CCD) detector to significantly improve the sensitivity, resolution, reproducibility, and repeatability of the laser light scattering particle sizing technique.

With the Saturn DigiSizer II, Micromeritics has again improved this particle size technique. Utilizing a state-of-the-art CCD detector containing over three million detector elements, Mie theory, and unique design and data reduction features, the Saturn DigiSizer II gives users an extremely high level of resolution and sensitivity not available in other laser particle sizing systems. The level of detail, accuracy, and resolution enables the extraction of all available information from the static light scattering pattern. Users can now measure the same material on multiple instruments located at different locations around the world and get the same, highly detailed size distribution measurement on each instrument. The Saturn DigiSizer II is fully automated and requires little operator intervention.

Measures both organic and inorganic particles ranging from 40 nanometers to 2.5 millimeters equivalent spherical diameter.
CCD detector contains over three million detector elements producing extremely high-resolution data.
Adjustable liquid sample handling unit for automatic sampling, dilution, and dispersion is available in both standard and low-volume configurations.
One computer can control up to two Saturn DigiSizers each with a liquid sample handling unit.
Optional MasterTech 052 Autosampler provides unattended analysis of up to 18 samples.
Fast, detailed results are repeatable on, and reproducible between, every Saturn DigiSizer II.
User-friendly analysis program includes wizards and intuitive screens and is designed to operate in the Windows® environment

Advantages

Superior sensitivity
Higher resolution
Superior analysis-to-analysis repeatability
Greater accuracy
Better reproducibility
Exceptional data quality
Fully automated system
Versatile sample handling options
Easy-to-use software
21 CFR Part 11 software option
IQ/OQ validation service option
No proprietary “black-box” algorithms

Applications

Ceramics

Particle Size information helps to determine curing and bonding procedures, control pore structure, ensure adequate green body strength, and produce a final product of desired strength, texture, appearance, and density.

Paints and Coatings

The particle size distribution of the pigment or filler influences the porosity, gloss, texture, color, color saturation, brightness, solids content, and film adhesion properties. The resulting porosity can control application properties such as fluidity, drying or setting time, and film thickness.

Cosmetics

The appearance, application, and packaging of cosmetics are influenced by the particle size distribution of the base powders, such as talc, and the pigments used in coloring.

Abrasives

Performance of abrasives, either in powder form or after being attached to a backing, is dictated by the size distribution of the abrasive powder. Over-sized particles lead to scratching and gouging. Undersized particles may lead to clogging of the abrasive papers.

Catalysts

Flow properties of fluid-cracking catalysts depend upon the particle size distribution of the particles. Surface area and pore structure of acid catalysts and catalyst supports result from the particle size distribution of the particles that are used to produce them

Mining

Refining efficiency of materials is related strongly to the particle size distribution of the raw mineral. For products that are used without chemical change, the size of particles taken from the mine may be too large for final usage. Analyses performed on the extracted minerals will help determine the amount of size reduction needed once the product reaches the processing plant.

Column Packing Materials

The back-pressure of the packed bed within the column is a direct function of the size of the channels through the bed and, thus, the size distribution of the column packing material. Over-sized particles create voids in the bed, reducing efficiency due to remixing of the separated sample components. Undersized particles lead to blockage of flow paths through the bed, increasing the back-pressure and analysis time. A proper distribution leads to greater separation efficiency.

Saturn II DigiSizer Configurations

The Saturn DigiSizer II System

Includes many options that allow you to tailor your instrument according to your specific needs. Multiple sample dispersion system options, an automatic autosampler, and a device for removing dissolved gases from the suspension liquid are available and contribute to the versatility of the system. These options are all designed and manufactured with the same care and attention to detail that produced the Saturn DigiSizer.

Liquid Sample Handling Units

The Saturn DigiSizer II’s sample handling unit ensures that every sample will be correctly dispersed. Micromeritics’ patented, state-of-the-art liquid sample handling units (LSHU) work with the instrument software to assure that sample suspension is of the proper concentration. A continuous flow through the reservoir provides a mixing action sufficient to keep all sample material suspended and prevents the settling of particles.

The LSHU has several automated features such as a built-in ultrasonic probe, automatic liquid level control, particle concentration detection, and a sample circulation system that continuously maintains dispersion. Auto-dispersion and auto-dilution features monitor the sample’s concentration and add liquid as needed until optimum concentration is obtained.

To reduce the possibility of sample carryover between analyses, the LSHU has a patented reservoir rinse design. While other designs simply fill and empty the reservoir to rinse, the Saturn DigiSizer’s LSHU has a feature that sprays the reservoir walls as the fluid level recedes. This removes residue that otherwise might cling to the surface.

Standard Liquid Sample Handling Unit

The standard unit includes a reservoir that is adjustable between 590 to 690 mL of dispersed sample with a circulation pump rate of 5 – 19 L per minute. It can circulate particles from 0.04 to 2500 µm. The high flow rate better supports particles that have an inherently higher settling velocity. In addition, the higher system clearance helps to avoid attrition of the particles during circulation.

Applications:

Coarse particles
High-density particles
Quantity of sample, liquid supply and/or waste disposal is not a problem

Low-Volume Liquid Sample Handling Unit

The low-volume unit includes a reservoir that is adjustable between 100 to 120 mL of dispersed sample with a circulation pump rate of 2 – 12 L per minute. It can circulate particles from 0.04 to 750 µm in diameter. The low-volume liquid sample handling unit reduces cost by using smaller amounts of sample, and reduces the expense of waste disposal.

Applications:

Sample quantity is limited
Supply of dispersion liquid is limited and/or expensive
Dispersion liquid may be hazardous to use and/or make disposal difficult

Particle Size Sample Preparation Accessories:

MasterTech Autosampler

The MasterTech Autosampler provides assurance that all samples are prepared and analyzed exactly the same way. The MasterTech is designed to increase throughput, repeatability, and reproducibility while reducing operator involvement. Up to 18 samples can be queued to run sequentially and completely unattended, including automatic stirring or sonication prior to transfer to the analysis system. The Saturn DigiSizer II’s operating software controls the MasterTech, and information about dispersion is stored in the sample file for future reference.

The MasterTech features a powerful ultrasonic probe for sample dispersion. Power to the probe tip is adjustable and the driving circuit is self-tuning for maintaining efficient and consistent sonic energy levels. A front-panel digital readout lets you know when the desired power is reached, and that same power is applied each time the method is repeated.

The AquaPrep can prepare 10 liters of water in less than 2 hours (at standard temperature and pressure) and ensures that you obtain the most accurate representation possible of the particle size distribution in your sample.

AquaPrep II

When using water as a suspension liquid during particle size analysis, it is possible for atmospheric gases to be released from solution forming minute bubbles that become incorporated with the sample dispersion. This has a disruptive effect on particle size analysis because the bubbles circulate through the measurement zone of the analyzer and are detected as if they were particles. This can result in the reporting of particle size classes that are not actually present. Removing these bubbles is required for obtaining the most accurate particle size data, particularly when using a highly sensitive analyzer like the Saturn DigiSizer II. Micromeritics’ AquaPrep solves this problem by recirculating water through a hydrophobic capsule consisting of many thin-walled capillaries. A vacuum pump provides low pressure on the outside of the capillaries. The result is a diffusion of dissolved air from the water through the capillary walls and removal through the vacuum pump.

Superior Data Reduction and Reporting

The Saturn DigiSizer II’s powerful, easy-to-use and versatile user interface provides all the convenient features you expect from a Windows-based program such as point-and-click menus, multitasking capability, copy to clipboard, and more. The familiar Windows format reduces the time required for training and eliminates the need for most off-line data manipulation, resulting in increased productivity. The analysis program is designed to operate in the Windows environment and includes wizards and intuitive screens enabling you to perform system operations quickly and efficiently.

In addition, Micromeritics’ confirm 21 CFR Part 11 software assists with compliance to FDA regulations. Combined with Micromeritics’ IQ and OQ services, the user can be assured that the Saturn DigiSizer II system is validated for accuracy, reliability, consistent performance, and provides safeguards to protect the integrity of analysis records. System access is limited to authorized individuals. Secure, computer-generated, time-stamped audit trails are integral parts of the software program.

Wide Range of Data Presentation Options With many instruments that employ the static light scattering technique, a final report of reduced data typically is the only output available. The Saturn DigiSizer II, however, allows you to access the raw data. For instance, an image of the scattering pattern (2-D and 3-D representations) can be displayed, or you can receive a 592-point intensity versus angle data report in tabular or graphical form. To allow a quick assessment of the fit of theoretical models to experimental data, you also can obtain an overlay plot of measured data calculated from Mie theory.

Reduction of Raw Data Based on Mie Theory Ensures Exceptional Data Quality

Micromeritics employs the Mie theory (or the operator can choose to use Fraunhofer for particles that are both large and opaque) to reduce experimental data using a well-published, non-negative least squares method. These theories describe light scattering via theoretical models. No modifications to the theory are made with the Saturn DigiSizer II, and no assumptions of modality or distribution type are used. This is made possible by the remarkably high resolution of the optical system allowing very narrow size classes to be used in fitting the data to Mie theory.

The application of Mie theory provides unambiguous size data. In addition to reporting the data, the Saturn DigiSizer II can generate a plot that shows how well experimental measurements compare with theoretical Mie calculations for the scattering pattern from the reported distribution.

Revolutionary Approach to Particle Sizing

CCDs were originally developed and used for high-sensitivity and high-resolution requirements of imaging for astronomy. The Saturn DigiSizer II captures the scattering pattern using a patented optical design that employs a CCD as the light detector. A high-definition digital representation of the scattering pattern, which contains all of the information required to determine the particle size distribution, is captured.

Micromeritics’ application of the CCD array eliminates the need for mechanical fine-tuning of optical alignment. The instrument is automatically aligned by re-mapping the CCD array so that the scattering angle assigned to each element is exact to less than 0.005 degree relative to the central, unscattered light beam. The Saturn DigiSizer II’s CCD array has more than three million detector elements. The resulting extremely high resolution makes it possible to detect subtle differences in the scattering patterns and, therefore, subtle differences in particle size distributions. These minute differences in sample particle size may indicate a manufacturing variance, corroborate or refute theoretical studies, or help explain natural processes. Higher resolution means greater knowledge about differences between samples.

Advanced design features enable the Saturn DigiSizer to measure a light scattering pattern over a broad range of scattering angles with a dynamic intensity range from 1 to 1×1010. Combined with the high angular resolution of the CCD, the detector system provides an effective resolution of several million pixels at different positions in the scattering pattern, each detecting minute variations in light intensity. The Saturn DigiSizer’s high resolution enables the instrument to detect extremely small variations in the scattering pattern that are not detected by lower resolution instruments. It is this high level of accuracy that allows the Saturn DigiSizer to provide more detailed and precise particle size information than laser diffraction particle sizing systems of conventional design

https://www.youtube.com/watch?v=lT4r4vld4_U

AccuPyc II 1345

gatscadmin — Wed, 06 May 2020 03:37:05 +0000

The AccuPyc II 1345 Series Pycnometers are fast, fully automatic pycnometers that provide high-speed, high-precision volume measurements and true density calculations on a wide variety of powders, solids, and slurries. After analyses are started with a few keystrokes, data are collected, calculations are performed, and results displayed. A minimal amount of operator attention is required.

Maintain product integrity with this non-destructive test
Eliminate error with programmable automatic repeat and data acquisition set to your tolerances to comply with your SOPs
Ability to use a variety of gases
Maximize your investment-Adaptive configuration to meet your sample size needs
Low-cost, minimal maintenance, and small footprint
Increase efficiency and compliance with barcoding compatibility
Speed of analysis, accuracy, repeatability, and reproducibility
Versatility of keypad or Windows software operation
Eliminate procedural steps with direct input from an analytical balance

Principle of Operation

This technique uses the gas displacement method to measure volume accurately. Inert gases, such as helium or nitrogen, are used as the displacement medium. The sample is sealed in the instrument compartment of known volume,the appropriate inert gas is admitted, and then expanded into another precision internal volume.

The pressures observed upon filling the sample chamber and then discharging it into a second empty chamber allow computation of the sample solid phase volume. Helium molecules rapidly fill pores as small as one angstrom in diameter; only the solid phase of the sample displaces the gas. Dividing this volume into the sample weight gives the gas displacement density.

Total Density

On an elementary level, the volume of a solid material can be calculated by measuring its length, width, and thickness. However, many materials have within their structure surface irregularities, small fractures, fissures, and pores.

Some of these voids or pores are open to the surface or closed within the structure of the solid material. Therefore, differences in the material volume depend on the measurement technique, measurement method, and the conditions under which the measurements were performed.

Density Type	Definition	Addressed by
True (Absolute)	The mass of a substance divided by its volume, excluding open and closed (or blind) pores	AccuPyc II
Skeletal(Apparent)	The ratio of the mass of the solid material to the sum of the volume including closed (or blind) pores	AccuPyc II
Envelope	The ratio of the mass of a substance to the envelope volume (imaginary boundary surrounding the particle)	GeoPyc
Bulk	Mass of the material divided by the volume occupied that includes interstitial space	GeoPyc
TAP	Apparent powder density obtained under stated conditions of tapping	GeoPyc with T.A.P. function

https://www.youtube.com/watch?v=p-pKEh1-oJg

Intergrated Thermo-Electric Temperature Control Solution

Materials tend to expand as they are heated, causing the same mass to occupy an increasing volume, thus lowering the substances density. Materials subjected to changing temperature may have a direct effect on volume, affecting accurate density determination.

The AccuPyc II TEC features a Peltier thermoelectric device for precise temperature control and stability. This instrument is an excellent option for use with temperature sensitive or viscous samples where environmental temperature cannot be adequately controlled.

Accurate temperature control from

15 – 36 °C (+/- 0.1 °C), adjustable in

0.1 °C increments

Available in 10-cm3 and 100-cm3 AccuPyc II TEC models. Also available in an analysis module version for remote operation when utilizing the AccuPyc II control modul. AccuPyc II TEC Software Density Determination of Semi-Solid Bituminous Materials

This AccuPyc solution can be closely correlated (< 0.15% difference) to results obtained with ASTM Test Method D70-09.

The ASTM method is burdensome and time consuming. Our approach offers an expedited, more robust, operator-independent method, with results in minutes.

Reproducible results in minutes, virtually eliminates operator error. Integral solution with software for bituminous material testing includes results for specific gravity, volume, and density

Peltier thermoelectric control (10 to 60 °C) provides excellent temperature control/stability and sample handling. Disposable sample cups limit cross-contamination and minimize cleaning of sample chamber between analyses.

Asphalt Sample	Average Density AccuPyc II TEC Solution (n=11) (g/cc)	%Relative Standard Deviation (n=11)	ASTM Method D70-9 Density (g/cc)	%Difference Between Methods
Sample A	1.01906	0.03	1.01758	0.1453
Sample B	1.02543	0.03	1.02536	0.0067
Sample C	1.01821	0.07	1.01848	0.0263
Sample D	1.02563	0.09	1.02576	0.0125

Density Measurements for Open- and Closed Cell Foams

The AccuPyc II unit can be ordered initially with the FoamPyc application installed. If you have a standard AccuPyc, you can upgrade with a software enhancement. A FoamPyc option for measuring open- and closed-cell foam materials is available in the following configurations for the standard and temperature- controlled pycnometers:

10-cm³ nominal cell volume (for conformance to ASTM and ISO methods)

100-cm³ nominal cell volume

FoamPyc Technique Determines Open Cell Volume in Foamed Materials

The FoamPyc option for the AccuPyc 1345 Density Analyzer lets you measure, calculate, and report the percentage of open cell volume in blocks of foamed or cellular plastic, glass, rubber, or metal.

These foamed materials have thin membranes or walls that separate internal cavities or cells. These cells can be open or interconnecting, closed or non-connecting, or a combination of open and closed. With the FoamPyc software, you can determine the percentage of sample volume occupied by open cells, as well as closed cells.

A Focus on Accuracy

The FoamPyc program ensures accuracy by correcting for punctured cells caused by cutting the block of material to obtain a sample. The volume of the cells that were opened on the cut surfaces of the sample are computed and their volume deducted from the analysis results so as not to overstate the true open-cell volume of the original uncut material.

The program uses correction calculations that follow ASTM Standard D 6226. Correction using cell dimensions method factors in cell chord length for estimating cut cell volume. Correction by re-cutting sample method, performs a second analysis to correct for opened cells, except this time the same sample is subdivided (re-cut) to expose twice the total surface area as before. Then, the second run is subtracted from the first run using a correction calculation, V= 2(V + D) – (V + 2D), where V is the true open-cell volume and D is the cut cell volume.

No correction method performs an AccuPyc analysis on the cut sample as is, which works well with samples that have mostly Compressibility method permits the volume change of soft, closed cell foams to be measured by applying progressively larger amounts of isotropic gas pressure and computing the volume occupied by the foam. Cell fracture method, evaluates the possibility of fracturing, which may occur when closed cell foam made of brittle material (having large, thin-walled cells) is exposed to pressure. This method applies first a small, controlled amount of pressure, and then performs a volume measurement. Next, a larger amount of pressure is applied. The sample is then returned to the first pressure and volume measurement is repeated.

Micromeritics announces the availability of a FoamPyc Sample Preparation Kit, Part No. 133/33009/00, to enhance your assessment of open pores in plastic foams. ASTM Test Method D-6226 describes the technique for extracting a sample of foam of specific dimensions then re-cutting it to double the amount of exposed surface, thereby deriving a correction for the pores opened in the initial cutting. The kit contains a knife, extra blades and a guide structure for both the first cutting of sample to dimensions and the re-cutting.

CorePyc-Density of Intact Core Samples

With a large-volume sample chamber, this pycnometer has been designed to address the specific needs of operations that require pore volume knowledge of intact drilling cores. This instrument improves sampling statistics by eliminating the need to break a core into many smaller pieces and run multiple analyses to obtain volume results. The CorePyc eliminates the need to run multiple analyses on large cores

Large sample chamber with a volume of approximately 2000 cm3

Sample chamber can accommodate a 95-mm (3.74 in.) diameter core of up to 278 mm (10.9 inches) in length

Analytical Balance Bundle

The AccuPyc weighing solution bundle provides one-touch transfer of mass data from the analytical balance directly to the AccuPyc’s Windows software. Direct transfer eliminates user error associated with manual entry of mass data. Optional Peltier temperature control eliminates environmental temperature variation and facilitates the handling of “hot” samples.

Seamless device compatibility
One-touch mass data transfer to AccuPyc for automatic calculation of density
Includes 120 X 0.1 mg electronic analytical balance with calibration weight
Optional Peltier thermoelectric control (10 to 60 °C) provides ambient temperature stability

Pharmaceutical Ribbons

With the skeletal density measured by the AccuPyc included in the setup parameters for the envelope density, the GeoPyc will calculate and report the percent porosity and total pore volume of the ribbon. This information has proven to be useful in controlling the mechanical properties of the material, compression force settings on the roller compactor, and subsequent tablet press settings.

Tablet Press

Pharmaceutical scientists realize that many of the physical, mechanical, and pharmacokinetics properties of tablets are influenced by the basic settings of a tablet press. Using the AccuPyc coupled with the GeoPyc, scientists are now able to determine quickly and easily the skeletal density, envelope density, total pore volume, percent porosity, and closed-cell pore volume of tablets produced with varying press settings.

Solid Fraction Data for Roller Compaction

Solid Fraction is a control parameter used in roller compaction operations. This control parameter assists in determining the optimal setting for speed, compression and nip angle in the roller compactor. Using the Solid Fraction as part of your SOP will ensure consistent product batch to batch, along with the end product having the designed and desired performance.

AccuPyc/GeoPyc Porosity Bundle

While skeletal and envelope volume measurements are significant in their importance as individual capacities, their combination permits the pharmaceutical scientist to also accurately calculate percent porosity and total pore volume. With this data a process engineer or quality assurance scientist can have greater knowledge of their process for improvement in both quality of product and optimization of the manufacturing process.

GeoPyc 1365 Envelope Density Analyzer

The GeoPyc utilizes a quasi-fluid displacement medium composed of non-hazardous microspheres having a high degree of flowability that do not wet the sample or fill its pores.

Determines envelope volume and density of monolithic samples as well as bulk volume and density of powdered materials. A variety of sample chambers is available to accommodate a wide range of sample sizes

AccuPyc II 1345 and the GeoPyc 1365 bundle
AccuPyc II 1345 Gas Pycnometer

The AccuPyc II 1345 Series Pycnometers are fast, fully automatic pycnometers that provide high-speed, high-precision volume measurements and true density calculations. The instrument completes most sample analyses in less than three minutes without sacrificing accuracy or compromising sample integrity.

Non-destructives test with speed of analysis
Eliminate errors with programmable auto repeat and data acquisition to a selected SOP
Adaptable configuration to accommodate samples of varying volumes

The AccuPyc II HP 1345 – High Pressure Density Measurement

The AccuPyc HP features a 100 cm3 sample capacity to determine the true volume and density of solids and powders at high pressures up to 500 psi. The bundle includes both a Control and Analysis Module and can be operated in either a stand-alone configuration using the internal keypad on the control module, or controlled with a desktop computer. The Control module is cable connected to the analysis module permitting remote analysis if desired.

Precision:

Reproducibility within +/- 0.04% nominal, full-scale cell chamber volume.

Accuracy:

To within 0.1% of reading, plus 0.1% of sample capacity

Additional Features Include:

Two separate modules, one for control with keypad the other for analysis. Modules are connected via provided cabling. The AccuPyc II HP 1345 High Pressure Density Measurement
Sample chamber can accommodate samples up to 48mm in diameter and up to 60mm in length
Guaranteed reproducibility to within 0.04% full scale volume
Transducer zeroing, calibration and operation are controlled by internal computer
Can be connected directly to analytical balance for transfer of sample mass without transcription error
Programmable for automatic repeat measurements or for data acquisition under user-selected tolerances
User-programmable number of purges prior to analysis
ASCII output from serial port can be captured by computer and used as input to popular spreadsheet programs
Helium is recommended as analysis gas, but nitrogen or other gases may be used for special applications.

GeoPyc 1365

gatscadmin — Wed, 06 May 2020 02:46:32 +0000

The GeoPyc automatically determines the volume and density of a solid object by displacement of Dry Flo, a solid medium. The medium is a narrow distribution of small, rigid spheres that have a high degree of flow ability and achieve close packing around the object under investigation. The particles are sufficiently small that during consolidation they conform closely to the surface of the object, yet do not invade pore space.

Repeatability and reproducibility are achieved by a controlled method of compaction. The sample cell in which the dry medium is placed is a precision cylinder. A plunger compresses the powder as the cell vibrates; the force of compression is selectable and, therefore repeatable from test to test. A preliminary compaction with only the displacement medium in the cell establishes a zero-volume baseline.

The sample is then placed in the cylinder with the dry medium and the compaction process is repeated. The difference in the distance ht the piston penetrates the cylinder during the test and the distance h0 it penetrates during the baseline procedure (h= h0 – ht) is used to calculate the displacement volume of the medium using the formula for the volume of a cylinder of height h, V= π r2h

Reporting Functions

The GeoPyc has multiple operational modes that are accessed through the instruments smart touch screen. Operating modes including full blank, computed blank, and reference solid calibration with variance, which allows you to optimize speed and accuracy for your specific application.

During analysis, indications of progress and preliminary results make it possible to track what is occurring. Sample-specific information can be entered into the analysis reports.

Available Reports:

Envelope Density
Volume Calibration
Blank Report
Force Calibration
Instrument Log

Total

Density Type	Definition	Addressed by
True (Absolute)	The mass of a substance divided by its volume, excluding open and closed (or blind) pores	AccuPyc II
Skeletal(Apparent)	The ratio of the mass of the solid material to the sum of the volume including closed (or blind) pores	AccuPyc II
Envelope	The ratio of the mass of a substance to the envelope volume (imaginary boundary surrounding the particle)	GeoPyc
Bulk	Mass of the material divided by the volume occupied that includes interstitial space	GeoPyc
TAP	Apparent powder density obtained under stated conditions of tapping	GeoPyc with T.A.P. function

Operational Features

The GeoPyc is operated from an intelligent touch screen. Data acquisition and reporting are fully automated for convenient incorporation in LIMS or other data concentrating systems.

A variety of sample chambers is available to accommodate a wide range of sample sizes. After the analysis, a light shaking or dusting completely removes the Dry Flo so the samples can be reused or retested. The GeoPyc has multiple operating modes including full blank, computed blank, and reference solid calibration with variance, which allows you to optimize speed and accuracy for your individual needs. During analysis, indications of progress and preliminary results make it possible to track what is occurring.

T.A.P Density Option

The GeoPyc T.A.P. density option obtains precise results comparable to conventional tap density analyzers, only it does it faster, quieter, and with a higher degree of reproducibility.

When equipped with the T.A.P. Density option, the GeoPyc measures the packing volume and calculates the bulk density of granular and powdered samples, including pharmaceutical and electrochemical materials, under a wide range of compaction conditions.

To determine T.A.P. density, the sample chamber is rotated and agitated while a precise specified force is applied to the sample. A force transducer measures the consolidation force in Newtons and the distance over which the consolidation piston and plunger travel is measured in steps. The user specifies the force applied and the number of consolidations per analysis. The GeoPyc averages the measurements from each consolidation and automatically calculates volume and density, and reports the results in cm³ and g/cm³.

Micromeritics Porosity Instrument Bundle

GeoPyc Envelope Density Analyzer

The GeoPyc utilizes a quasi-fluid displacement medium composed of non-hazardous microspheres having a high degree of flowability that do not wet the sample or fill its pores.

Determines envelope volume and density of monolithic samples as well as bulk volume and density of powdered materials
A variety of sample chambers is available to accommodate a wide range of sample sizes
T.A.P. Density option – measures the packing volume and calculates the bulk density of granular and powdered samples

AccuPyc/GeoPyc Porosity Bundle Bundle

The AccuPyc II 1340 Series Pycnometers are fast, fully automatic pycnometers that provide high-speed, high-precision volume measurements and true density calculations. The instrument completes most sample analyses in less than three minutes without sacrificing accuracy or compromising sample integrity.

Non-destructives test with speed
of analysis
Eliminate errors with programmable
auto repeat and data acquisition to a selected SOP
Adaptable configuration to accommodate samples of varying volumes

MIC SAS II

gatscadmin — Tue, 05 May 2020 16:29:32 +0000

The quality of the data produced by surface area and pore volume analyses depends greatly on the cleanliness of the sample surface. All Micromeritics’ sample preparation devices accept helium, nitrogen, argon, and other non-corrosive gases.

What is Air-permeability Particle Sizing?

The air-permeability technique is well established for measurement of the Specific Surface Area (SSA) of a sample powder. The SSA measured by this technique has been found to be a useful parameter in various industries such as pharmaceutical, metal coatings, paints, and even geological samples.

The MIC SAS II utilizes dual pressure transducers to measure pressure drop across a packed bed of powder. By varying the sample height and porosity while controlling the flow rate of air through the sample, the SSA and average particle size can be determined using the Kozeny-Carman equation.

Features and Benefits

Superior Software – Sets a world-wide standard for instrument operation, data acquisition and handling, reporting and systems integration
Quick and Easy Set-up – Simple step by step set-up, easy to follow; ensuring that no parameters are over looked
Real Time Data Display – Data can be viewed as it is acquired simplifying method development
Fisher Mapping – Optimizes data agreement with customizable Fisher correlation
ASTM Approval – Fully compliant with ASTM B330-12 and C721-14 standards for particle sizing of alumina, silica, and metal powders and related compounds. B330-15 – Metal Powders; C721-15 – Al2O3, SiO2 – Ceramics & E2980 – 15 – General particle size
Fully Automated Analysis – Sample compaction and pressure stability are computer controlled for high repeatability
Report Generation – Automatically creates PDF reports with custom company logos and typestyles
Security Features – Optional password protection ties samples to user ID’s and protects configuration parameters from unauthorised change
New Powerful Intuitive Touch Pad – User interface increases productivity and enables easy creation and retrieval of SOPs.

Direct Comparison of SAS and FSSS

Comparison trials between the Micromeritics SAS and Fisher FSSS have been carried out using a variety of samples. The graphs above compare the mean particle size data from the two instruments on powders of different sizes. One plot is based on results for inorganic (mainly tungsten) metal; the second on organic samples (mostly pharmaceuticals). There is exceptional correlation between the two sets of data. Numerous extensive studies have come to the same conclusion.

Sentinel Pro

gatscadmin — Tue, 05 May 2020 14:43:01 +0000

Particles are suspended in a flowing stream, backlit by a high speed, Xeon strobe and then photographed by a high-resolution digital camera at up to 127 frames per second. Individual particle images are viewed directly and captured as a video file for post-run processing.

The dynamic turbulent flow path provides a three-dimensional, random orientation, direct view of the moving particles within the sensing zone. Dynamic imaging provides greater particle detail regarding convexity, sphericity, symmetry and aspect ratio when compared to static imaging.

SentinelPro Unique Design Benefits

High speed, 127 frames per-second rated Digital Camera, with up to 5 Mpix resolution, captures live images of thousands of particles
More than 30 shape parameters are recorded, including circularity, ellipticity, opacity, mean diameter, smoothness, aspect ratio, fiber length and many more
All analyzed particles have thumbnail images saved for post-run viewing and shape analysis, both in grey scale and binary views.
Ability to compare different analyses via histogram overlays for all analyzed shape parameters
Scatter plot correlates two shape measurements and can be utilized as a process quality control criterion as an at-line application within unit operations.
Unique and powerful software permits the user to simplify data processing to a pass/fail reporting or choose to extend data analysis to a full suite of post processing image and shape analysis reports.
Multi-Run sample trending – Statistical Process Control capability and ability to track shape changes over user defined time intervals.
Instrument Qualification feature includes NIST standards and detailed Quality Assurance documentation.
Particle Concentration Correlation– adjust concentration reporting to correlate

Shape Model Descriptions

Circle Models :

Equivalent circular area diameter
Equivalent circular perimeter diameter
Bounding circle diameter
Mean radius diameter
Circularity
Smoothness
Compactness

Rectangle Models:

Bounding rectangle length, width
Bounding rectangle aspect ratio
Rectangularity

Fiber Models:

Fiber length, width
Fiber aspect ratio
Fiber curl

Ellipse Models:

Equivalent elliptical area, width, length
Bounding ellipse width, length
Elliptical aspect ratio
Ellipticity

Polygon Models:

Polygon order
Interior angle
Convexity

Irregular Models:

Feret length, width
Feret aspect ratio
Surface uniformity

Pixel Intensity:

Opacity
White Fractions
to traceable reference concentration standards.

Two Models Available

SentinelPro Stand-Alone Instrument:

This model is a fully independent, stand-alone instrument to process samples for Shape analysis by Dynamic imaging. Unit includes an internal peristaltic pumping system with chemically resistant tubing throughout the fluid path.

Its flexible design enables automatic fluidic cycling, optic conversions for extending the particle size range and permits customization for higher viscosity samples by our Custom Engineering Department to meet your specific needs.

Particle Size Range:

1-300um

10-800um

SentinelPro Shape Module:

The SentlinelPro Shape Module automatically takes an aliquot of sample from the reservoir of your current laser light scattering instrument.

No need to change or re-validate your currently established method or process, instead easily integrate the Shape Module within the fluid path of your existing size-only instrumentation.

As the sample is being analyzed, the SentinelPro taps into the sample reservoir of your sizing instrument, removes an aliquot of no more than 30ml of the sample, performs real-time shape analysis and returns the sample to the existing instrument without jeopardizing sample or the integrity of your particle sizing instrument.

Particle Size Range

1-300 um

10-800 um

100-2500 um

SentinelPro Features:

Thumbnail Extraction from Specific Points in Histogram:

This model is a fully independent, stand-alone instrument to process samples for Shape The SentinelPro employs two important features: random orientation and recirculation of the sample. These two features help to ensure a true representation of the sample, as well as accurate data.

When viewing particle thumbnails, the left-mouse button will display all the shape measurement values for that selected thumbnail.

The right-mouse button will allow the user to eliminate that specific particle from the database and statistics.

Useful when, for example, a single air bubble is not wanted in the database.

Particle Concentration Correlation

Adjust concentration reporting to correlate to reference concentration standards.
More accurate, improved concentration results.
References to traceable and recognized count standards

SentinelPro Instrument Features

High speed, high resolution optics
Real-time results
More than 30 size and shape measures
Particle thumbnails in gray scale and binary imagery
Multi-run overlaying of shape data
Sieve correlation capability
Upgradeable optics
Organic fluid capability
Security and regulatory compliance
Flexible, fluidic design
Four size range model options
Real-time data backup for remote viewing
Automated recirculating, sample handling module
3-Dimensional analysis with random orientation
Simple, reliable hardware for low maintenance
Unique integration with smartphone app allows for remote data analysis of all results and thumbnails in real-time
Particle classification feature allows users to automatically have a full analysis for each subcomponent in a mixed sample

SentinelPro Software Features

SSSSpin Tester

gatscadmin — Tue, 05 May 2020 13:33:56 +0000

The SSSPin Tester provides repeatable and consistent data by first consolidating the material using centrifugal force to compress the sample inside the sample holder. After the initial compaction step, the SSSpinTester then completes the analysis routine using the same centrifugal force to determine the yield strength of the material.

SSSpinTester Features

Fast analysis – results in less than fifteen minutes, full 10-point flow function obtained in less than one hour
Minimal Sample Volume Required – 0.5 cc or less. Minimizes precious or expensive sample waste
One test acquires full data set – no multiple measurements required
Extended consolidation pressure range – 0.05 kPa to 72 kPa
Direct measurement – eliminates the need for extrapolation of data
Small footprint – requires minimal bench-top space
Meets Regulatory Requirements – Certified CE compliant and conforms to FDA 21 CFR Part 1

For Formulators, Important Improvements in Analyzing Precious Powders

Sample Size	Consolidation Pressure	Quick Results
0.06 to 0.1gm per test	10 Pa ot 50 kPa	Single test to obtain data

Current testers can require	Current testers can require	Current testers can require
Greater than 50 gm.	Minumum of 1k Pa	5 tests to obtain data

SSSpinTester Specifications

Physical:

Length: 18in.
Width: 16in.
Height: 15in. (includes the feet)
Mass: ~22.5Kg or ~50lbs

Sample Volume:

Requires 0.5cc per test

Consolidation Pressure Range:

0.05 kPa to 72 kPa

Electrical:

Voltage: 85 – 264 VAC
Frequency: 50/60 Hz –
Single Phase 9A

Environment:

Temperature: 0 to 50 °C (32 to 122 °F) –
With RH maximum of 78%

Typical Applications

Powdered Metals

Obtaining strength values at low consolidation pressures allows prediction of optimal powdered metal behavior. The SSSpinTester can measure the strength of heavy metal powder at actual fill pressure values for direct correlation to processing conditions

Additives (for energy)

Additives are typically introduced to coal combustion streams through pneumatic conveying. Measuring the strength of these powders at low to moderate compaction pressures can help with conveying this material.

Ceramics

Density variations of sintered ceramic powder can cause significant problems with dimensional tolerances of the final parts. Filling pressures are very low and the density variations depend on the strength of the material. Segregation can be prevented by the cohesive properties of the bulk

Pharmaceutical

Strength testing during formulation of pharmaceutical API powders is possible when only a very small quantity of the material is available. The weight variance from tablet to tablet is directly related to how the die fills. The filling depends on the strength of the material at low pressures

Food(fine powders only)

Food engineers need a quick test to measure the cohesion properties (strength and density) to determine if a particular mix will cause flow problems in the unit operation being used at the food plant. The SSSpinTester offers a fast and accurate measure of material strength at a full range of consolidation pressures.

Chemical

Often an engineer wants a quick test to measure the cohesion properties (strength and density) of a particular formulation. The optimal powder is one that has enough cohesion to prevent segregation, but not enough to cause density variations

Catalysts

Measuring the strength of catalyst material at low consolidation pressures can allow the scientist to determine if a catalyst will channel and correlate this information to the life of the catalyst in a fluid bed. The SSSpinTester measures the cohesiveness (strength and density) of the catalyst powder at actual process operating condition

Cosmetics

Decisions can be made regarding the size and shape of the powdered ingredients to optimize packaging success. The SSSpinTester can give the formulator and process engineer the data at actual pressures that are needed for successful packaging

Uniaxial Powder Tester

gatscadmin — Tue, 05 May 2020 05:20:12 +0000

Uniaxial testing first involves the construction of a consolidated powder column. This is then removed from its confining sleeve before being fractured through the application of a vertical stress, directly measuring the uniaxial Unconfined Yield Strength (uUYS). This technique can therefore be used to assess and rank powder flowability.

Cohesive powders have relatively strong inter-particular forces, which encourage the particles to bond together rather than moving easily relative to one another. By contrast, in non-cohesive powders, the tensile forces between particles tend to be much weaker.

Uniaxial powder testing is a direct and reliable method for measuring the uUYS and Flow Function of powders.

Benefits of the Uniaxial Powder Tester

Direct uUYS (σc) and Flow Function (FF) measurements
Fast
Repeatable
Low Cost
Versatile
Easy to use
Intuitive, easy to interpret results
Robust
Bespoke software

The uniaxial Unconfined Yield Strength (uUYS) is a measurement of stress required to break or fail a previously consolidated, unconfined column of powder. The uUYS is similar to the Unconfined Yield Strength (UYS), a parameter derived from rotational shear testers. However, it should be noted that due to the different consolidation and failure protocols of uniaxial and rotational testers, it does not always follow that values for uUYS are identical to values of UYS.

Features of the Uniaxial Powder Tester

The UPT’s level of automation and low operator input means the instrument delivers highly repeatable data.

Off-Instrument Consolidation

The innovative offline Consolidation Station provides users with additional testing capabilities. It allows powder samples to be subjected to a range of environmental conditions, separately from the main instrument, such as elevated temperature and humidity for extended periods under the desired MPS. This allows for the simulation of many industrial processes without occupying instruments for long periods of time.

The Consolidation Station can provide up to 100 kPa of applied stress and can be placed in an oven at temperatures up to 70°C.

Principles of Uniaxial Testing

Sample is loaded into a cylinder and consolidated with a Major Principal Stress (σ1) to form a powder column

Major Principal Stress and cylinder are removed to leave a free-standing consolidated powder column

Column is fractured through the application of a compressive stress, and derive uniaxial Unconfined Yield Strength

The Challenge

Practical constraints have previously inhibited the exploitation of uniaxial testing. These include:

Constructing a free-standing powder column
Ensuring a uniform density and stress throughout the entire powder column
A practical, easy to use powder tester that can be used with a wide range of powders

The UPT has overcome these challenges by:

Developing a sleeve design enabling the creation of a free-standing column of powder
Using a double-ended consolidation method to ensure uniform density and stress

FT4 Powder Rheometer

gatscadmin — Tue, 05 May 2020 03:23:09 +0000

It differs from other powder testers in many ways but when assessing industrial value, three features are critical:

The ability to simulate powder processing conditions, by testing samples in consolidated, moderately stressed, aerated or fluidised state
The application of multi-faceted powder characterisation to assess dynamic powder flow, bulk and shear properties to construct the most comprehensive understanding of how a powder behaves
Unparalleled sensitivity, enabling the differentiation of powders that other testers classify as identical

Features

Fully automated test programs and data analysis
Conditioning mode provides unparalleled repeatability
Range of sample size, 10ml to 160ml (in addition a 1ml Shear Cell is available)

How It Works

The FT4 employs unique technology for measuring the resistance of the powder to flow, whilst the powder is in motion. A precision ‘blade’ is rotated and moved downwards through the powder to establish a precise flow pattern. This causes many thousands of particles to interact, or flow relative to one another, and the resistance experienced by the blade represents the difficulty of this relative particle movement, or the bulk flow properties.

Excellent reproducibility and sensitivity, this is achieved by moving the blade in a precise and reliable way. The advanced control systems of the FT4 accurately set the rotational and vertical speeds of the blade, which defines the Helix Angle and Tip Speed.

https://youtu.be/te6GPT-Wyv8

FT4 Powder Rheometer Methodologies

The FT4 is a truly universal powder flow tester, with four categories of methodologies, defined as Bulk, Dynamic Flow, Shear (in accordance with ASTM D7981) and Process.

Proven Applications

The FT4 has application in all powder processing industries, including Pharmaceuticals, Fine Chemicals, Food, Cosmetics, Toners, Metals, Ceramics, Plastics, Powder Coatings, Cements and Additive Manufacturing. Applications extend to:

Die / Capsule Filling
Tablet Compression
Hopper Flow
Wet Granulation End Point & Scale Up
Flow Additive Selection & Optimisation
Humidity Effects
Electrostatic Change
Mixing / Blending
Feeding
Segregation
Attrition
Dry Powder Inhalers
Caking
Milling
Conveying
Wall Friction & Adhesion
Hopper Design
Compact Hardness & Payoff
Vacuum Filling
Agglomeration

Whether your objective is to optimise a formulation in a development environment, predict in-process performance, understand batch differences, or to ensure the quality of raw materials or intermediates, the FT4 will provide valuable and unique information that will help you address your powder flow challenges.

Bulk properties are not a direct measurement of flowability or shear, but nevertheless influence process performance and product attributes. The FT4 Powder Rheometer® measures three types of bulk powder properties: –

Density

Density defines the relationship between mass and volume. In principle this seems a simple concept, but the nature of powders means that their packing structure can change easily and significantly. Therefore when defining density, it is essential to ensure the packing state is well known and can be reproduced. This is achieved on the FT4 using a Conditioning cycle. When combined with other features such as the built in balance and Split Vessels, which allow a precise volume to be attained, the Conditioned Bulk Density can be measured with unprecedented levels of accuracy.

Compressibility

The measurement of Compressibility is achieved by applying increasing levels of compressive force with a piston to a conditioned powder and measuring the change in volume as a function of the applied load. The Vented Piston ensures that air trapped within the powder is able to readily escape, and the high resolution of the position measurement system allows for precise definition of Compressibility, expressed as a percentage change in volume for a given applied normal stress.

Compressibility = percentage change in volumn after compression (%)

Alternatively this data can be represented as a Compressibility Index or as Bulk Density, both as a function of applied normal stress.

Permeability

Permeability is a measure of the powder’s resistance to air flow. Not to be confused with an Aeration test, this method utilises the vented piston to constrain the powder column under a range of applied normal stresses, whilst air is passed through the powder column. The relative difference in air pressure between the bottom and the top of the powder column is a function of the powder’s permeability. Tests can be completed under a range of normal stresses and air flow rates.

This important material property is relevant in many applications, including tabletting and filling, for example. In a tabletting process, the efficiency of air removal during the compression step will influence the mechanical properties of the compact, and should air be retained within the tablet due to low powder permeability, capping or lamination may occur. Within a filling application, the ability of the air to “back flow” out of the die or container through the powder as it enters depends on the bulk permeability and this will influence fill rate and fill consistency. Whilst permeability is a relatively simple bulk property, it is important in many processes and applications and should be accurately measured.

The Importance of Conditioning

Anyone who has worked with powders will know how easily they change their density, just as a result of handling them. Tip them from a beaker and they aerate, or tap the beaker on the bench and observe a reduction in volume as the powder becomes compacted.

These changes in density are a consequence of changes in the stress applied to the powder. As discussed previously, variation in stress level is likely to have a major impact on how the powder behaves, within a process or application, but also during a measurement. It is therefore essential to ensure the powder is prepared for any test by first establishing a uniform stress in the powder bed and eliminating pockets of air or localised compaction.

This preparation step is called Conditioning and is a simple, but effective mechanical process designed to prepare the sample for the following measurement. Utilising the same unique technology that is used in the dynamic methodologies (see previous pages), the Conditioning process involves gentle displacement of the whole sample in order to loosen and slightly aerate the powder. The aim is to disturb and gently drop each particle in order to construct a homogenously packed powder bed, removing any precompaction or excess air and ensuring the results from the following test are independent of how the operator handles the powder and places it into the testing vessel.

Powder Conditioning with Blade

A conditioning cycle is usually completed prior to every test in order to remove the variability introduced by the operator during loading of the sample, and any residual compaction from previous tests. The exception is where an intentionally consolidated sample is being evaluated, in which case conditioning is not employed.

The FT4 Powder Rheometer employs unique technology for measuring the resistance of the powder to flow, whilst the powder is in motion. A precision ‘blade’, or impeller, is rotated and moved downwards and upwards through the powder to establish a precise flow pattern. This causes many thousands of particles to interact, or flow relative to one another, and the resistance experienced by the blade represents the difficulty of this relative particle movement, or the bulk flow properties. The more the particles resist motion and the harder it is to get the powder to flow, the more difficult it is to move the blade.

As the blade moves through the sample, the FT4 measures both rotational and vertical resistances, in the form of Torque and Force respectively. It is important to capture both signals as it is the composite of these two values that quantifies the powder’s total resistance to flow.

Using the calculation of WORK DONE, it is possible to represent both the Torque and Force signals as a Total Flow Energy, the energy required to move the blade through the sample from the top to the bottom of the powder column. However, because the values of torque and force are constantly changing, it is necessary to calculate the energy for each small distance travelled. This is the calculation of Energy Gradient, the energy measured for each millimetre of blade travel, expressed in mJ/mm.

Work Done = Energy = (Resistance x Distance travelled)
where ‘RESISTANCE’ is the combined Torque and Force
Energy Gradient = Energy per mm of blade travel

Calculating the area under the Energy Gradient curve provides the Total Flow Energy, representing the powder’s resistance to being made to flow in a dynamic state.

Energy Gradient is calculated directly from the measurements of Torque and Force

Confined and Unconfined Powder Flow

Two types of powder flow pattern are typically employed for quantifying flowability: –

Forced (or confined) Flow

A measure of the powder’s flowability when forced to flow, such as through a screw feeder or in an active feed frame. This property is defined as the Basic Flowability Energy, BFE, and is measured during the downward blade movement. The powder is confined by the closed bottom end of the test vessel.

Direction of movement downwards

Low Stress (or unconfined) Flow

A measure of the powder’s flowability when unconfined, such as during low stress filling, or low shear blending. This property is defined as the Specific Energy, SE. In this measurement, the resistance to flow is measured as the blade traverses from the bottom of the vessel to the top. As there is no solid surface at the top of the vessel preventing the powder from dilating and moving upwards, the powder is unconfined during this test.

Direction of movement upwards

The regimes of confined and unconfined flow are very different and so it is important, when correlating data with process performance, to identify which regime is most representative of the process being considered.

Powder flow properties are complex and cannot be quantified by a single number. Flowability must be considered in relation to the conditions imposed by the process and application. Powders may exhibit “good” flow if loosely packed, but “bad” flow after consolidation. Some powders may flow well as long as flow rates are relatively high, however they may stop flowing when moved more slowly.

The FT4 Powder Rheometer has been designed to allow the effect of each of these External Variables to be investigated. By closely simulating process conditions in the measurement cell, the powder’s response to each variable can be quantified.

External variables include:

Conditioning
Aeration
Flow (Shear) Rate
Moisture
Electrostatic Charge
Storage Time

Using Dynamic Methods to Quantify the Effects of External Variables

Basic Flowability Energy is a measure of a powder’s flow properties when the powder is in a loosely packed state (following conditioning). Using this same dynamic methodology, it is possible to quantify how powder flow properties change when it is subjected to any of the external variables (defined in the previous sections).

Aeration

In order to quantify the influence of air, a controlled air supply can be introduced through a porous mesh at the base of the powder column. This method is not just to simulate processes and applications where air is intentionally introduced into the powder, such as during conveying, drying and in dry powder inhaler applications, but importantly to explore the cohesive forces that exist between particles.

Air In Aeration Test

Cohesive forces are notoriously difficult to measure, but can now be accurately and directly quantified by assessing how aeration changes the flow properties of the bulk powder. Cohesive forces are a combination of Van der Waal’s and electrostatics, and tend to “bond” particles together. The introduction of air to the powder column attempts to separate adjacent particles and overcome these cohesive forces. If the forces are weak, each particle will become mechanically separated from its neighbour and the powder will become fluidised. The measured resistance to flow, the Aerated Energy, AE quantifies the strength of the cohesive forces.

For powders with weak cohesive forces, the Aerated Energy tends towards zero as the powder becomes fully aerated. Powders with moderate to high cohesion will exhibit a reduction in flow energy when aerated, but to a much lesser extent. In these cohesive powders, the tensile forces are too strong for the air to overcome and the particles do not separate. Instead a channel is established in the powder though which the air passes, and the corresponding Aerated Energy remains relatively high, even at high air velocities.

Contrasting Basic Flowability Energy with Aerated Energy results in the Aeration Ratio, AR, where:

Aeration Ratioxx = Basic Flowability Energy / Aerated Energyxx = BFE / AExx
where ‘xx’ defines the air velocity in mm/s at which the Aerated Energy measurement is taken.

The Aeration Ratio is a measure of the powder’s sensitivity to aeration.

Consolidation

The effect of consolidation on flow properties can be directly quantified by the Consolidation Energy, CE. This is a very similar test to the Basic Flowability Energy, but is completed on a powder sample that has first been subjected to a level of consolidation. Like the BFE method, the flow energy is determined as the blade moves through the powder sample from the top to the bottom. Initially a Conditioning cycle is employed to generate a uniform packing density, before the powder is subjected to a number of taps, in order to induce consolidation in the sample, prior to it being measured. The resulting increase in resistance to flow is quantified by the Consolidation Energy.

It is also possible to consolidate the powder using an applied normal force. This compaction technique more closely simulates how powders would behave during storage, in contrast to behaviour during transport or in other environments where they are subjected to vibration. In both methods, the powder is first consolidated before the flow energy is measured.

Contrasting the Consolidated Energy with the Basic Flowability Energy provides a relative change in powder flow properties as a function of consolidation. It is a measure of the powder’s sensitivity to consolidation and is expressed as the Consolidation Index, CI, where:

Consolidation Index, CIxx = Consolidation Energyxx / Basic Flowability Energy = CExx / BFE

where ‘xx’ defines either: –

The number of taps, or
The applied normal stress during compaction (kPa)

Traditional tapped density based methods, such as Carr’s Index and Hausner Ratio, seek to define certain aspects of powder flowability based on a volume change, as a result of tapping the sample. As the graph above illustrates, changes in density may be as high as 40%, however flowability may actually have changed by 1000% as a consequence of tapping. This direct measurement of Consolidated Energy quantifies that the flow properties are in fact 10 times worse after tapping and illustrates why inferring flow characteristics from density measurements is often misleading. After all, from a processing and application perspective, the interest is mostly to determine whether the product will flow, rather than whether its density has changed.

Flow (Shear) Rate Sensitivity

In addition, powders with high flow rate sensitivity will require an optimised and specific mixing configuration if blend uniformity is to be attained. The advantage of powders with low flow rate sensitivity is that low shear mixing operations can be employed, whilst still ensuring homogeneity, minimising the chances of particle attrition and electrostatic charge evolution which are commonplace in high shear blending. Powders exhibiting high flow rate sensitivity normally require high shear processes in order to blend efficiently.

Powders typically exhibit different flow behaviour when moved at different flow rates. This means that they may flow freely at one speed and badly at another. This sensitivity to changes in flow rate has a number of implications for powder processors and can seriously effect process stability.

Unlike many liquids, powders are rarely Newtonian in nature, exhibiting a complex behavioural relationship with the speed at which they flow. In fact it is common that powders are more difficult to move at lower speeds than at higher velocities, meaning that if a process is subject to variation in the rate powder moves through it, blockages may occur should flow rates drop below a critical value.

Utilising the dynamic methodologies of the FT4 Powder Rheometer, and good experimental design, it is possible to investigate a number of other behavioural properties of powders. These include: –

Caking

Powder consolidation with time

Moisture

The influence of free moisture on the behaviour of the powder

Segregation

The potential for particles to rearrange according to their size / density

Attrition

Particle friability, resulting in changes in particle size, shape and surface area

Electrostatics

Changes in behaviour as a function of electrostatic charging

Agglomeration

The formation of agglomerates from primary particles, usually as a function of being processed

The FT4 Powder Rheometer® also includes a Shear Cell accessory which allows the powder’s shear properties to be quantified. The technique has been published by the ASTM International Committee D18 on Soil and Rock. Shear testing is a very different technique to that of dynamic testing, and always characterises the powder in a consolidated state. It is also a fairly static test, measuring powder behaviour as it transitions from no-flow to flow.

For these reasons, it is clear to see why shear cells are ideally suited to predicting powder behaviour in process operations where the powder is consolidated and where flow rates are low and / or sporadic. They have been successfully applied for understanding powder behaviour in hoppers, and also provide some of the data needed to carry out a hopper design exercise (based on Jenike stress theory developed during the last century). However, as a consequence of the regime in which they operate, they are less suited to predicting powder behaviour in low stress or dynamic applications, such as mixing, filling, feeding and conveying.

Operating Principle

At very low speeds, a shear (or horizontal) force is applied to an upper layer of powder whilst the adjacent lower layer is prevented from moving (or vice versa). The force continues to increase but no relative movement at the shear plane occurs until the shear force is sufficiently high to overcome the powder’s shear strength, at which point the powder bed ‘yields’ and the upper layer of powder slips against the lower.

Several types of shear cell design have emerged over the last 50 years, however each employs the same concept of shearing one layer of powder against the other. The designs most frequently in use today are rotational in nature, and are preferred as they allow the two layers of power to be sheared relative to one another over a large distance, in contrast to translational designs that quickly exhaust their range of displacement.

Each design has its strengths and weaknesses, and all types remain in use today. For a detailed comparison of features, benefits and weaknesses, please contact us directly for further information.

In a typical shear cell test sequence, several shear tests would be carried out at different levels of normal stress. The data produced represents the relationship between shear stress and normal stress, which can be plotted to define the powder’s Yield Locus. In simple terms, the higher the shear stress for a given normal stress, the less likely it is that the powder will yield and begin to flow when confined under a similar consolidation stress in a hopper or other vessel.

It is possible to apply a number of mathematical models to this data, but it is important to consider that in doing so, trends may be exaggerated or reduced. Fitting Mohr stress circles to the yield locus identifies the Major Principle Stress (Sigma 1) and Unconfined Yield Strength (Sigma c), and the ratio of the former to the latter quantifies the Flow Function, FF. Flow Function is a parameter commonly used to rank flowability, with values below 4 denoting poor flow and above 10, good flow.

Wall Friction

The Wall Friction test provides a measurement of the sliding resistance between the powder and the surface of the process equipment. This is particularly important for understanding discharge behaviour from hoppers, continuity of flow in transfer chutes and tablet ejection forces. It is also useful when investigating whether a powder will adhere to the wall of process equipment and various other surfaces, such as the inside of sachets, capsules and other packaging material.

The measurement principle is very similar to the shear cell test, but rather than shearing powder against powder, in this test a coupon of material representing the process equipment wall is sheared against the powder in question. The FT4 Wall Friction accessory allows for a range of coupons to be investigated, and bespoke surfaces can be manufactured if required.

Data is typically represented as a plot of shear stress against normal stress, allowing the determination of Wall Friction Angle (phi). The greater the wall friction angle, the higher the resistance between the powder and wall coupon.

This data can be utilised in specific studies, as outlined above, but is also required as part of a hopper design exercise.

Hopper Design

Hoppers are used extensively throughout the processing environment and whilst they are often considered to be simple systems, they are responsible for causing a great deal of process interruption and product quality issues.

If a powder possesses properties that are not optimised for the hopper geometry and equipment surface, then flow from the hopper may be variable or even none existent. However, since the pioneering work carried out by Andrew Jenike in the mid twentieth century, it has been possible to utilise data from shear cell and wall friction tests to calculate the critical hopper dimensions to ensure good flow.

The FT4 comes with fully automated hopper design software, which takes the results directly from shear cell and wall friction tests and runs the data through the hopper design algorithms. The result is a fully automated hopper design exercise in less than 3 hours.

Today, this hopper design process remains one of the very few fundamental approaches to equipment design, based on an understanding of material properties and the stress regime within the equipment. Unfortunately, such an approach is not available for mixers, feeders, conveyers, dryers, compression processes or any of the other unit operations routinely used in powder processing.

SPECTester

gatscadmin — Tue, 05 May 2020 02:44:22 +0000

Using state-of-the-art spectroscopic technology, the innovative SPECTester is capable of analyzing a sample comprised of up to six individual components and provides a simple report indicating why and how much the sample material is segregating. Fully automated, the instrument provides data about component concentrations, particle size differences, and product uniformity.

The SPECTester is capable of measuring segregation by particle size, sifting, fluidization, angle of repose, chemical component, and air entrainment. It is fully capable of identifying both primary and secondary segregation mechanisms. The SPECTester can be used in R&D environments to research a materials properties prior to going into production as well as in production plants for real-time quality control.

Key features of the SPECTester include:

Measurement of mixtures with up to six components
Fully-automated operation with reports of how much the material mixture is segregating
Optional fluidization module quantifies segregation potential of fluidized beds
Provides data on variations in component concentration, particle size, and product uniformity
50 segregation points measured across the sample bed
Simulates process conditions to identify segregation by sifting, fluidization, angle of repose, and air entrapment
Indicates product quality control issues
Provides uniformity index for sample and segregation variance data
Data can be exported to PDF and Excel formats
Fast analysis – 10 to 30 minutes to complete a run depending on the sample and application
USB Interface
CE compliant

Data Generated by the SPECTester:

The SPECTester provides the user with three main tools:

Segregation intensity number
Uniformity number
Excel-ready data base describing the segregation behavior of both the mixture and
the individual components as they travel through a process

The segregation intensity number

For each individual component indicates how much that ingredient is contributing to the overall segregation occurring within the material mixture. Use the segregation intensity number to determine which component and/or components, in the mixture is/are problematic. This number is between 0 and 1. A segregation intensity number larger than about 0.25 means that specific ingredient is contributing significantly to the segregation issue.

The uniformity number

Is the inverse of the segregation intensity number. This number is also between 0 and 1. The uniformity number represents the overall uniformity in concentration of each unique component within the mixture. A larger uniformity number indicates that the ingredient appears through the mixture relatively uniformly. A smaller uniformity number indicates that the ingredient turns up in the mixture pile to a non-uniform degree.

The Excel-ready data base

(.csv format) can be used to create graphs, tables and charts that describe the segregation behavior (or lack therefore) of the material mixture and the individual ingredients in reports and presentations.

ELSZ 2000

gatscadmin — Mon, 04 May 2020 09:46:22 +0000

Highly Accurate Zeta Potential Measurements of Concentrated Solutions

Patented FST technology utilizes a transparent electrode to minimize path length and reduce multiple scattering effects. This technology permits accurate zeta potential measurement in a wide concentration range of 0.00001 to 40% (w/v) unique to the ELSZ-2000, eliminating the need to dilute samples.

True Determination of Electrophoretic Mobility

The ELSZ-2000 negates the effects of electroosmosis by measuring zeta potential at five different locations within the cell. As a result, the instrument can calculate and accurately measure true electrophoretic mobility, resulting in a highly accurate determination of zeta potential. This also provides the ability to determine multi-modal distributions of zeta potential mixtures.

Broad Particle Sizing Range with Increased Sensitivity

The ELSZ-2000 has a dynamic sizing range of 0.1 nm to 12.30 µm in a concentration range of up to 40% w/v, and a sensitivity for molecular weight to as low as 250 Da. Dual correlators, log-scale for larger particles prone to time decay and linear scale for small particles, provide high sensitivity measurements in multicomponent samples.

Wide Range of Measuring Cells

The ELSZ-2000 features a wide range of measuring cells available for both zeta and nano particle size measurements. Included is a unique solid sample cell for zeta potential measurement of coated surfaces, films or treated glass slides.

There are three models available:

ELSZ-2000-1 – nano particle sizing instrument
ELSZ-2000-2 – zeta potential instrument
ELSZ-2000-3 – combination nano particle sizing and zeta potential instrument.

ELSZ-2000 Sample Cells

The ELSZ-2000 has an array of compatible sample cells for both zeta potential and nano particle size measurements. Each sample cell provides additional measurement capabilities of samples in liquid suspensions

Design improvements include:

High-precision x-ray tube with ruggedized design and extended life
Windows operating software with Ethernet connectivity provides point-and-click selection, networking, printer selection, cut-and paste, and much more
Utilization of a simplified pumping system ensures fast and easy maintenance
Reduced noise level for a quieter working environment
A maintenance reminder, based on the number of analyses performed, alerts you when it is time for routine maintenance
Computer-controlled mixing chamber temperature improves repeatability and reproducibility
A highly versatile and interactive reporting system provides a wide range of custom data presentation options and now includes particle settling velocity and grain size in Phi units

Particle Size

– For use with the ELSZ-2000-1 and ELSZ-2000-3

Standard nano particle sizing cell (0.09) mL) – one included with ELSZ-2000-1 and ELSZ-2000-3
Disposable nano particle sizing cell (0.90 mL)
Micro volume nano particle sizing cell (20 μL)
Flow cell assembly for nano particle sizing

Zeta Potential

– For use with the ELSZ-2000-2 and ELSZ-2000-3

Standard sample flow cell assembly (0.70 mL) one included with ELSZ-2000-2 and ELSZ-2000-3
Micro volume cell assembly (130 μL)
Disposable cell for zeta potential measurement
High concentration sample cell for zeta potential measurement
Low conductivity sample cell for zeta potential measurement
Solid sample cell for zeta potential measurement

Principles of Particle Sizing

Particulates dispersed in a solution are normally subject to Brownian motion. The motion is slower with larger particles and faster with smaller particles. When laser light illuminates particles under the influence of Brownian motion, scattered light from the particles shows fluctuation corresponding to individual particles.The fluctuation is observed according to the pinhole type photon detection method, so that particle size and particle size distributions are calculated.

Principle of Zeta Potential Measurement

In most cases, colloidal particles possess a positive or negative electrostatic charge. As electrical fields are applied to the particle dispersion, the particles migrate in oppositely charged directions. As particles are irradiated in migration, scattering light causes Doppler shift depending on electrophoresis mobility. ELSZ-2000 software calculates the amount of Doppler shift followed by electrophoretic mobility and zeta potential by combining a heterodyne system and photon correlation method to perform Fourier transform (FFT) Slipping level Major part of medium of obtained correlation function.

Zeta Potential Measurement Features of the ELSZ-2000-2 and ELSZ-2000-3

Measures zeta-potential of a sample suspension in the range of -500 mV to +500 mV with concentrations from 0.001% to 40%
Reliable measurements based on electrophoretic light scattering technology conforms to ISO 13099-2
Accurately measures both dilute and concentrated suspensions
Capable of evaluating the surface charge on solid surfaces, film, etc. based on electroosmotic probing
Variety of sample cells available

The ELSZ-2000 is capable of obtaining high resolution zeta potential analyses even with multi-component samples. In the example on the right, a mixture of five polystyrene latexes of different particle sizes was measured. Five spectrums corresponding to each latex component was detected. The zeta potential of these components were in the range of -45mV to -10⁷ mV.

Evaluation of Dispersion Stability by Zeta Potential/Particle Size

As the absolute value of zeta potential is larger, many colloidal particles show good dispersability as the electrostatic repulsion becomes stronger. However, as the zeta potential registers close to zero, the particles become unstable and are likely to aggregate.

Concept of FST Method

FST – Electrophoretic mobility measurement of concentrated suspension using orward cattering through ransparent electrode. By conventional methods, scattered light from a concentrated suspension cannot be measured correctly due to multiple scattering (A). The FST method detects the scattered light from particles through a transparent electrode. The optical path length is minimized to reduce the effects of multiple scattering. Thus, the ELSZ-2000 can perform a zeta potential measurement of a concentrated suspension with a high degree of accuracy (B).

Determination of True Electrophoretic Mobility

When the measurement of electrophoresis is actually taken, an electroosmotic current is generated in the cell due to an electric charge on the cell wall. With a negatively charged cell wall, the electroosmotic flow phenomenon causes the positively charged ions and particles to gather together by the cell walls. The solution located by the cell walls migrates toward the negative electrode during electrophoresis. The solution located in the cell center moves in the opposite direction (toward the positive electrode) to compensate for the flow by the cell walls.

Therefore, an electroosmotic flow is created during electrophoresis. The ELSZ-2000 is designed to measure electrophoretic mobility at several points in the cell to obtain a position (i.e. static) not influenced by electroosmotic flow. As a result, the instrument can calculate and accurately measure electrophoretic mobility, even if the electroosmotic profile of the system is asymmetrical due to adsorption or sedimentation of the sample.

Evaluation of the Surface charge of Solid Sample by Zeta Potential

Novel method to measure the zeta potential of solid surfaces using probong particles.

Surface charge of the solid sample can be evaluated. Determination of electrostatic interactions between particles and flat surfaces
Easy to use. Large sample size, min: 14 x33mm, Max: 16 x37mm up to 5mm thickness.
Solid surface modifications analysis, addictive effect studies and particle adhesion. Zeta potential vs. Ph/additives volume also available
Wide sample application. Soft sample like fibres can also be measured.

Applications:

Fibres and textiles.
Thin film
Shampoo and condition
Membrane and filters
Biomedical surfaces
Semiconductor industry
Polymer surfaces and coatings
Optical glass polishing
Protein adsorptive studies
Paper and pulp industry
Antimicrobial surfaces
Packaging materials
Recording media
Printing and paint

Molecular Weight Determination of Macromolecules with ELSZ-2000:

There are two modes of MW determination of macromolecules provided by the ELSZ200. The first method is by using dynamic light scattering (DLS) size information with the use of Mark Houwink Sakurada equation and the second method is by using Static Light Scattering techniques (SLS)

The first method uses the diffusion constant obtained from the DLS analysis and by providing two empirical constants associated with the macromolecules–solution under analysis; the molecular weight can be calculated from the Mark Houwink Sakurada equation.

The second method is using Static Light Scattering information in the determination of the Molecular weight of any macromolecules in solution. The scattering intensity is a function of the molecular weight and the concentration of the macromolecule solution as described by Rayleigh equation.

The Scattering intensity of a series of macromolecules solution with known concentrations is being measured. Using a Debye plot, Molecular weight can be calculated by a linear extrapolation line from the Debye Plot.