The word “Pycnometry”, derived from the Greek word pyknós, meaning ‘dense’, has long been identified with
volume measurements. Quantachrome’s automatic gas pycnometers have long been identified as the instruments
of choice to accurately measure the true density of solid materials by employing Archimedes’ principle of fluid
displacement, and Boyle’s Law of gas expansion. An inert gas, rather than a liquid, is used since it will penetrate
even the finest pores and eliminate any influence of surface chemistry. This ensures quick results of the highest
accuracy. Helium is generally used as the displacement gas due to its size and inert behavior. Other gases, such as
nitrogen, are also routinely used with no measureable sacrifice of performance.
Principle of Operation
A sealed sample chamber of known volume is
pressurized to a target pressure with the displace-
ment gas. Once stabilized, this pressure is recorded.
A valve is then opened allowing the gas to expand
into a reference chamber whose volume is also
known. Once stabilized, this second pressure is
recorded. The pressure drop is then compared to
the behavior of the system when a known volume
standard underwent the same process.
To ensure accurate results on a gas pycnometer
there exists a proper ratio between the volumes
of the reference chamber and the volume of the
sample chamber. If this ratio is too large or too
small, the accuracy of your measurement will suffer. This is why gas pycnometers manufactured by
Quantachrome Instruments possess multiple built-in
reference volumes. The combination of adjustable
sample chamber sizes and multiple internal reference
chambers ensures that a single gas pycnometer from
Quantachrome Instruments will provide accurate
results over a range of volume applications that would
require up to three distinct instrument models from
Benefits of Gas Pycnometry
• Fast and accurate results (in as little as 1 minute)
• Reliable and reproducible results
• Wide range of sample volumes and configurations
• Instrument has small footprint
• Uses small amount of gas pressurized to < 20 psig
The true density of active and excipient materials
is used to determine their composition for both
development and process control efforts.
See USP .
The crystallinity of plastics used in coatings as well
as the true density of dry pigment materials are
monitored via gas pycnometry measurements. See
The density of cement is used for accurate calculation
of powder characteristics and, measured after set up, is
important for formulation and stability determination
The true density of calcined petroleum coke is an
important quality specification for these materials.
See ASTM D2638.
Broken spheres are undesirable. The ratio of intact
to fractured spheres is routinely evaluated using gas
True density values assist in assessing whether or not
certain impurities are present in the composition of
soils. See ASTM D5550.
Ceramics and Catalysts
Density values are used in the development,
manufacturing, and troubleshooting of refractory
materials to confirm desired crystal phase is present
and closed porosity is absent. See ASTM C604.
Polymers and Foams
Gas pycnometry is widely used to characterize the
relative amounts of crystalline and amorphous phases
as well as open and closed cells present in polymer
materials. See ASTM D6226.
Dried Film Coatings
The density of dried film coatings is used in the
assessment of their volatile organic content.
See ASTM D6093.
The true density of complex metal shapes formed by
powder metallurgy is used to track physical properties
throughout the processing of such structures.
See MPIF Standard 63.
True Density Analysis of Powders,
Foams and Bulk Solids
The PentaPyc 5200e Automated Gas Pycnometer is
utilized for high throughput measurements of true
density and volume of solids.
The PentaPyc features five analysis ports for
simultaneous sample preparation and sequential
analysis. Its automatic repeat measurement mode
ensures that the results fall within a user-specified
tolerance or achieve a user-specified maximum
number of runs.
The appropriate expansion (reference) volume is
automatically chosen by a microprocessor according
to the sample cell selected. Reports include density
and volume results with statistics.
In addition, the instrument features a USB printer port, a
second USB port for a flash/thumb drive, Ethernet port
for PC (automatic operation via web browser) or network.
Connection and an RS232 balance interface. Complete
with three inter-changeable sample cells (10,50 & 135 cc)
for each station and full set of calibration spheres.
Dimensions (WxDxH): 42 cm x 58 cm x 32 cm
Weight: 33 kg
Sample Volume: 0.1 - 135 cm 3
Resolution: 0.0001 g/cm 3
‡ Accuracy and Reproducibility:
• Large Sample Cell (135 cm 3)
Volume Accuracy-better than +/- 0.02%
Repeatability -better than +/-0.01%
• Medium Sample Cell (50 cm 3)
Volume Accuracy-better than +/- 0.03%
Repeatability -better than +/ 0.015%•
• Small Sample Cell (10 cm 3)
Volume Accuracy-better than +/- 0.2%
Repeatability -better than +/- 0.1%
Analysis Time: In as little as 1 minute Purge Modes:
• Continuous flow with user selectable time; or
• Pulse with user selectable number of
pressurization/depressurization cycles; and
• Flow/Evacuation Rates: User-selectable with
precision needle valve.
Pressure Range: 1-20 psig
Gas Requirements: Compressed gas (preferably ultra
high purity helium or nitrogen for helium-permeable
samples) regulated to 20 psig (140 kPa).
‡ Accuracy and reproducibility vary with sample volume
and preparation. Values given above are for well-prepared
samples with volumes of 50% of the cell volume.
The PentaFoam 5200e instruments provide automated measure ments of open-closed cell content, cell
compressibility, and cell fracture. Both units are supplied with a f oam cutting kit (see Accessories).
Temperature Control Option
For measurements that require a fixed, known temperature, All gas pycnometers manufactured by Quantachrome
Instruments have the hardware necessary for connection to an external temperature controller bath.
True Density Analysis of Powders,
Foams and Bulk Solids
Easy to Use
Samples are easy to load and unload. Measurement
protocols are easily invoked at the unit or via a
A new analysis requires only that correct sample ID
and mass be entered. The entire analysis protocol
remains in memory for the next analysis.
Time Saving Operation
Automatic analysis of up to 5 samples frees the
operator for other tasks while the unit works
Emphasis on Precision and Accuracy
The sample chamber is vented and the pressure
transducer is zeroed before every expansion, not just
when a fresh sample is initialized. The appropriate
expansion chamber is automatically employed.
Focus on Reproducibility
The pycnometers retain volume calibrations in memory
– regular adjustment is not required. The system
suitable and stable measurement conditions.
Optimal performance is assured by multiple sample cup
sizes and multiple expansion chambers.
Pre-Calibrated, Re-Calibrate Any Time
All pycnometers are factory calibrated and ready to use
out of the box. Re-calibration, when necessary, is easy
to do with the supplied set of reference volume spheres.
Access to Results
Detailed reports may be printed, emailed, or saved
Results are retained internally in text and pdf format.
Direct Input of Sample Weight
The PentaPyc/PentaFoam instruments can connect
to an electronic balance to obtain the sample weight
directly. Weight can also be entered at the keypad or
via the PC.
Analyses can be set up and started using the built-in
keypad or a PC.
Customizable Analysis Parameters
Define sample preparation protocol, number of
expansions, repeatability acceptance criteria,
equilibrium conditions, and target pressure.
Calibration spheres can be purchased with a formal
Report of Calibration provided by the National Institute
of Standards and Technology: Not simply traceable to
NIST, but actually measured by NIST.
Automatic Troubleshooting Alerts
Loss of gas pressure, unstable pressure, and other fault
conditions are automatically reported.
Automatic Gas Pycnometers
PentaPyc / PentaFoam 5200e instruments from Quantachrome are the ultimate true volume and true density
measurement units due to their reliability, accuracy, reproducibility, and minimal operator involvement. Their wide
range of interchangeable sample cell sizes (from 1 to 135 cc) served by a range of appropriate reference volumes make
them perfect for either quality control or research and development environments.
Non-Elutriating Sample Cells
Non-elutriating sample cells have perforated lids that
prevent instrument contamination when working with
fine powders such as carbon black, toner, or fly ash.
A 2-stage gas regulator with CGA fitting and an isolation
valve on the output with a 1/8 inch gas line connector is
recommended. A suitable gas regulator assembly is avail -
able for purchase from your local Anton Paar salesperson.
Temperature Control Module
A compact yet powerful thermoelectric heater/chiller
circulates liquid to the heat exchange system for precise
Foam Sample Preparation Kit
Includes a sample holder with guide slots for reproducible
preparation of 1” cubes of rigid foams as required in ASTM
D6226. Also included are a knife and a circular punch.
The Foam Sample Preparation Kit is supplied with the
PentaFoam 5200e and can be purchased separately.
S ample Cells and Adapter Sleeves
Durable, easy to clean stainless steel sample cells and
adapter sleeves are provided with each pycnometer.
Additional sizes and Delrin versions are available
to best fit your specific application needs.
True Density Analysis of Powders,
Foams and Bulk Solids
Our global service staff assure you that Quantachrome Instruments will continue
to be the reliable engines of material characterization laboratories. We offer you
the flexibility of choosing from service contracts tailored to provide you with the
response time, service package, and spare parts discounts that best fit your needs.
Quantachrome spare parts are certified to work with our instruments. We provide
rapid response spare parts orders, and keep large inventories of replacement parts
and hardware available.
Our fully equipped, state-of-the-art powder characterization laboratory
(email: firstname.lastname@example.org), provides the option of contracting for
expert testing services. Laboratory services are also available to validate the
applicability of our products prior to your purchase using your actual samples.
Lifetime Application Support
We view the field support of our instruments as an essential component of our
business strategy. Our expert scientists are always available to answer questions
on applications, or the use of our instruments. We do this as a standard service
regardless of whether you have a service contract with us or not.
Partners in Science
Quantachrome has a scientific research department consisting of world renowned
experts in material characterization. Our staff, led by team conducts collaborative
research projects with leading material research labs around the world. They
regularly publish articles in leading peer reviewed journals, and speak at technical
symposiums around the world.
For almost half a century Quantachrome’s
scientists and engineers have revolution-
ized measurement techniques and
designed instrumentation to enable the
accurate, precise, and reliable characteri-
zation of powdered and porous
materials. We have an unwavering
commitment to providing state of the art
technology, along with superior and
unparalleled customer service and
Our commitment to customers is to
support you before, during, and after
the sale throughout the lifetime of our
instruments. This is a big commitment
because our products are so robust and
reliable that we regularly find many still
in use for decades.
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