Model 1305
MultiVolume Pycnometer
(S/N: 801 and higher)
Operator’s Manual
Part No. 135-42803-01 March 2001Swagelok is a registered trademark of Crawford Fitting Company.
TABLE OF CONTENTS
1. GENERAL INFORMATION
Introduction . . . 1-1 Conventions . . . 1-2 Equipment Description . . . 1-3 Precautions and Intended Use . . . 1-5 Specifications . . . 1-6
2. INSTALLATION
Unpacking and Inspection . . . 2-1 Equipment Damage or Loss During Shipment . . . 2-1 Equipment Return . . . 2-1 Selecting the Location . . . 2-2 Selecting the Voltage . . . 2-2 Gas Supply . . . 2-6
3. OPERATION
Controls and Components . . . 3-1 Controls . . . 3-1 Components . . . 3-4 Startup . . . 3-8 Preparing and Weighing the Sample . . . 3-11 Performing an Analysis . . . 3-12 Calculating the Sample Volume, Density, and Specific Volume . . . 3-14 Verifying Calibration . . . 3-15 Zero Offset . . . 3-15 Scale Factor . . . 3-15 Calibrating the Analyzer . . . 3-16 Definition of Volumes to be Calibrated . . . 3-16 Calibration Procedure . . . 3-18 Turning Off the Analyzer . . . 3-19
4. TROUBLESHOOTING
Unstable Pressures . . . 4-1 Falling Pressures . . . 4-1 Rising Pressures . . . 4-2 Nonreproducible Results . . . 4-2 Incorrect Results . . . 4-3Model 1305 MultiVolume Pycnometer Table of Contents
Pressure Indicator . . . 4-4 Fails to Illuminate . . . 4-4 Constantly Indicates Nearly the Same Pressure . . . 4-4 Slow Return to Zero Pressure Upon Venting . . . 4-5
5. ORDERING INFORMATION
APPENDICES
Appendix A: Theory Appendix B: Forms
Appendix C: Sample Results Computation Program Appendix D: Derivation of Calibration Equations
CHAPTER 1
GENERAL INFORMATION
•
Introduction
•
Conventions
•
Equipment Description
•
Precautions and Intended Use
GENERAL INFORMATION
This manual describes how to install and operate the Model 1305 MultiVolume Pycnometer.
Introduction
This manual is divided into chapters and appendices as follows:
Chapter 1 Provides a general description of the Model 1305 MultiVolume Pycnometer and its specifications. Also provided in this chapter are precautions and intended use for the pycnometer.
Chapter 2 Describes how to unpack, inspect, and install the Model 1305 MultiVolume Pycnometer.
Chapter 3 Provides a description of the controls and components of the Model 1305 Multivolume Pycnometer, as well as operating in-structions.
Chapter 4 Provides troubleshooting and user maintenance information.
Chapter 5 Provides ordering information for parts and accessories.
Appendix A Provides theoretical information concerning the Model 1305 MultiVolume Pycnometer.
Appendix B Provides forms for you to copy and use when operating the pycnometer.
Appendix C Provides information on the computation program for sample results.
Appendix D Provides calibration calculations.
Conventions
This manual uses the symbols shown below to identify notes of importance and warnings.
Notes contain information pertinent to the subject matter.
Warnings contain information to help you prevent actions which could cause personal injury.
Conventions Model 1305 MultiVolume Pycnometer
Equipment Description
Figure 2-1. The Model 1305 MultiVolume Pycnometer
The MultiVolume Pycnometer 1305 accomplishes the measurement of skeletal vol-umes by observing the reduction of gas capacity in the sample chamber caused by the presence of the sample. Since helium or most other suitable gases pene-trate even the smallest pores and surface irregularities, the volume obtained per-mits computation of the ultimate theoretical density of the solid comprising the sample if there are no closed pores.
The sample chamber with the sample present is first charged to a gas pressure of about 20 psig (unit of measure for the Model 1305). Subsequent expansion of this gas charge into a second precisely measured volume which previously was at the same temperature and at zero psig results in a second pressure which be-comes progressively smaller for larger samples. Application of mass balance equa-tions for the gas permits easy computation of the sample volume when the
volumes of the empty sample chamber and the expansion chamber are known and the pressure drop ratio upon expansion is known.
The MultiVolume Pycnometer 1305 differs from similar products in that three dif-ferent size sample chamber configurations are provided, each containing an associ-ated expansion volume sized to provide the maximum accuracy and resolution for that range. A schematic diagram of the MultiVolume Pycnometer 1305 is shown in Figure 1-2. Theoretical information is provided in Appendix A.
Figure 1-2. Schematic Diagram of the Model 1305 Gas In FILL RATE Valve Over-Pressure Relief Valve
FILL Valve Filter Pressure Transducer Sample Chamber VENT RATE Valve VENT Valve <5/>5 Valve <35/>35 Valve PREP/TEST Valve
Equipment Description Model 1305 MultiVolume Pycnometer
Precautions and Intended Use
The Multivolume Pycnometer 1305 is designed to measure rapidly the skeletal volume of powders, granules, or any other solid objects having low vapor pres-sures and to permit computation of absolute density when weight information is supplied.
It will measure with diminishing effectiveness the volumes of materials which have appreciable vapor pressures, i.e., materials which slowly evaporate or subli-mate or are contaminated with such vapors. Materials having extremely high sur-face areas or which absorb appreciable amounts of helium may present some difficulties and require additional computations or extra measurement steps. Use both hands when lifting the instrument, one under each side panel.
Observe the following precautions when operating the Model 1305 Pycnometer:
• Unplug the power cord before removing the rear panel to gain access to in-ternal components. Connections carrying potentials as great as 240 V can be encountered.
• Limit the gas inlet pressure to the 140-170 kPa (20-25 psig) range to avoid possible damage to the instrument. An overpressure relief valve is provided internally to protect the instrument and operator but it may cause loss of large amounts of helium if the 170 kPa (25 psig) setpoint is ex-ceeded. Exercise standard safety precautions when handling compressed gases.
• Before attempting to open the sample chamber: always close the gas inlet valve, open the vent valve, and wait until the internal pressure falls to less than 1.0 psig. Failure to do so may result in powdered samples being pulled from the sample cup and contaminating the internal spaces of the instrument or being propelled toward the operator.
• Finely powdered samples may be pulled into the internal components of the instrument if excessively high fill or vent flow rates are used, espe-cially if a vacuum is being used. Always begin with the flow rate controls set at or near minimum when running such samples. Gradually increase the flows as to achieve adequate but safe rates of pressure change.
• Do not spill abrasive particles between the walls of the 5- and 35-cm3 sample chamber inserts and the sample chamber. The inserts may stick in the sample chamber or scratch the O-ring sealing surface near the top of the sample chamber and cause leaks. Always clean the sample chamber and sample chamber inserts with a clean, soft, lint-free cloth or tissue be-fore loading the sample chamber insert. Avoid scratching or denting the sample chamber or sample chamber inserts or the inserts may fail to fit the chamber.
Specifications
The Model 1305 MultiVolume Pycnometer has been designed and tested to meet the specificaitons provided below.
Characteristic Specification
————————— SAMPLE VOLUME ————————— 150 cm3 Range:
(indicates 35 to 150 cm3)
Cylindrical sample chamber, 5.080 cm (2.000 in.) diameter x 7.620 cm (3.000 in.) usable depth; allows up to 154.4 cm3 nominal volume. Sample cup measures 4.572 cm (1.800 in.) inside
diameter x 7.277 cm (2.865 in.) usable depth, holds up to 119.5 cm3 bulk volume of powder or other material.
35 cm3 Range: (indicates 5 to 35 cm3)
Sample chamber insert with a cylindrical sample chamber, 3.556 cm (1.400 in.) diameter x 3.556 cm (1.400 in.) usable depth; allows up to 35.32 cm3 nominal volume. Sample cup measures 3.406 cm (1.341 in.) inside diameter x 3.429 cm (1.350 in.) usable depth holds up to 31.25 cm3 bulk volume of powders or other material.
5 cm3 Range:
(indicates less than 5 cm3)
Precision sample chamber insert with a
cylindrical sample chamber, 1.842 cm (0.725 in.) diameter x 1.842 cm (0.725 in.) usable depth; allows up to 4.905 cm3 nominal volume. Sample cup measures 1.689 cm (0.665 in.) inside diameter x 1.755 cm (0.691 in.) usable depth holds up to 3.933 cm3 bulk volume of powder or other material.
——————— ACCURACY/REPRODUCIBILITY ——————— Depends upon nature of sample. Samples containing water vapor or other vola-tile matter will adversely affect results. Extremely high specific surface area samples may require a computed correction. Clean, dry samples of medium to low surface area will run as follows:
150 cm3 Range: ±0.2% (±0.3 cm3) of full scale guaranteed;
±0.1% or better usually attained
35 cm3 Range: ±0.2% of full scale (±0.070 cm3) guaranteed;
±0.1% (±0.035cm3) usually attained
5 cm3 Range: ±0.2% of full scale (±0.010 cm3)guaranteed.
±0.1% (±0.005cm3) usually attained
Specifications Model 1305 MultiVolume Pycnometer
Characteristic Specification
———————————— THROUGHPUT ———————————— Up to 15 samples per hour when sample preparation not required. Duplication of measurement requires less than two minutes for sample already in chamber. —————————— UTILITIES/SUPPLIES —————————— Accommodates to standard power mains worldwide.
Voltage: 100, 120, 220 or 240 VAC +10%
Current: 0.25 A (100/120 VAC); 0.15 A (220/240 VAC)
Frequency: 50/60 Hz
Gas: Helium at 140 to 170 kPa (20 - 25 psig) for specified performance. Any other dry
noncorrosive gas may be used with reduced accuracy. Nitrogen is recommended for minimum performance loss if helium is unavailable.
Vacuum: Attachment point for customer-supplied vacuum pump to permit thorough removal of vapors from samples if required.
—————————— EXPOSED MATERIALS —————————— Sample Cups, Chamber,
Inserts, and Caps: Aluminum
O-rings: Buna-N
Tubes, Fittings, etc. Copper and Brass
———————————— ENVIRONMENT ———————————— Temperature: 19.5 - 25 °C (67 - 77 °F) and stable during
runs for specified accuracy without recalibration on the 5 cm3 range; 10 - 40 °C (50 - 104 °F) and stable during runs for all other ranges or the 5 cm3 range with calibration at the operating temperature.
0 - 50 °C (32 - 122 °F); storage and shipping. Humidity: 20 - 80% (non-condensing)
Characteristic Specification
—————————————— CABINET ——————————————
Physical: 31.1W x 18.7H x 38.1D cm
(12.25W x 7.36H x 15.0D in.)
Weight: 7.9 kg (17.4 lbs)
Specifications Model 1305 MultiVolume Pycnometer
CHAPTER 2
INSTALLATION
•
Unpacking and Inspection
•
Selecting the Location
•
Selecting the Voltage
INSTALLATION
This chapter describes how to unpack and inspect the equipment, how to install the analyzer and the analysis program, and how to verify operation of the ASAP 2405 system.
Unpacking and Inspection
When you unpack the shipping cartons, carefully compare the packing list with the equipment actually received, while checking for equipment damaged during shipment. Be sure to sift through all packing materials before declaring equip-ment missing.
It is very important to save the shipping cartons when equipment is to be declared as damaged or lost. The inspector (or claim investigator) must examine the cartons prior to completion of the inspection report.
Equipment Damage or Loss During Shipment
When equipment is damaged or lost in transit, you are required to make note of the damage or loss on the freight bill. The carrier, not the shipper, is responsible for all damage or loss. In the event of equipment damage or loss during ship-ment, contact the carrier of the equipment immediately.
Equipment Return
Micromeritics strives to ensure that all items arrive safely and in working order. Occasionally, due to circumstances beyond our control, equipment is received which is not in working condition. When it is necessary to return equipment (damaged either during shipment or while in use) to Micromeritics for repair or replacement, the following procedure should be followed:
1. Tag or identify the defective equipment, noting the defect and circumstances, if any, under which the defect is observed.
2. Reference the sales order or purchase order, and provide the date that the equipment was received.
3. Notify the Micromeritics Service Department of the defect and request ship-ping instructions. The service department will assign a Returned Materials Authorization (RMA) number. Write the RMA number on the outside of the shipping carton.
Model 1305 MultiVolume Pycnometer Unpacking and Inspection
Selecting the Location
The Model 1305 Pycnometer performs best in a regulated temperature environ-ment. It should be installed on a workbench 75-90 cm (30-36 in.) high in a loca-tion free of drafts from either a forced-air heating or cooling system. It should not be located near a window where it will be exposed to direct sunlight. A square meter (10 ft2) of free space to one side and a few centimeters to the rear of the instrument should be provided for working space. Ready access to an analytical balance capable of weighing to 1 mg for sample preparation is advanta-geous. Space near the instrument in which to mount securely the appropriate gas cylinder will be necessary if the workbench is not plumbed to supply the gas. Sharp variations in ambient pressure caused by fans or doors closing rapidly may cause erratic results; avoid these locations.
Selecting the Voltage
All instruments leave the factory set for 120 VAC and with the line fuse re-moved. The correct setting of the universal power entrance must be checked and the appropriate fuse installed before the Model 1305 can be operated. The Model 1305 is designed to operate with either 100, 120, 220 or 240 VAC at 50 or 60 Hz. Voltage selection and fusing are made at the power connector which is lo-cated on the right side panel of the unit.
The power cord should be disconnected from the Model 1305 before re-moving the cover from the power input connector. Failure to disconnect the power cord could result in electrical shock.
1. Make sure the power cord is disconnected from the pycnometer.
2. Using a pointed object, remove the fuse block and cover assembly from the power connector on the right side of the pycnometer.
Figure 2-1. Removing Fuse Block and Cover Assembly
3. Pull the voltage selector card straight out of the power connector housing.
Figure 2-2. Removing Voltage Selector Card
4. Orient the voltage selector card so that the desired voltage is indicated at the bottom. Orient the indicator pin so that it points upward as shown in the fol-lowing illustration.
Figure 2-3. Voltage Selection
5. Insert the voltage selector card into the power connector housing with the edge containing the desired voltage first and with the printed side facing the power ON/OFF switch.
Figure 2-4. Inserting Voltage Selector Card
Pin
Voltage
Voltage Selector Card
Model 1305 MultiVolume Pycnometer Selecting the Voltage
6. Fuse the input power line according to local safety practices. The input power connector can be used with either a single-fuse arrangement or a dou-ble-fuse arrangement, as shown in the following illustration.
Figure 2-5. Fusing Arrangements
The power cord should be disconnected from the pycnometer when installing or replacing fuses. Failure to do so could result in electrical shock.
a. Observe the position of the fuse block, using the previous figure for ref-erence. If the single-fuse arrangement is desired, position the fuse block so that the side with the single-fuse slot and the jumper bar is away from the cover.
If the double-fuse arrangement is desired, position the fuse block sso that the side with the double-fuse slots is away from the cover.
b. If the fuse block is positioned properly for the fusing desired, proceed to Step c.
If the fuse block is not positioned properly for the fusing desired: 1) Remove the fuse block retaining screw.
2) Lift the fuse block from the cover. 3) Rotate the fuse block.
4) Mount the fuse block to the cover. 5) Replace the retaining screw.
Fuse Retaining Screw Fuse Block Cover Jumper Bar Fuse Block Fuse Block Cover Fuse Fuses SINGLE-FUSE DOUBLE-FUSE
The fuses used in the pycnometer must be identical in type and rating to that specified. Use of other fuses could result in electrical shock and/or damage to the pycnometer.
c. Insert appropriate fuse(s) for the input power source. Refer to the chart below for the appropriate fuse rating.
Power Source Fuse
100-120 VAC 0.50 Amp, 3AG, Slow Blow
220-240 VAC 0.25 Amp, 5 x 20 mm Slow Blow, Type T 7. Insert fuse block and cover assembly into input power connector and snap it
into place. Once the fuse block and cover assembly are in place, the position of the indicator pin shows the input power selected.
Figure 2-6. Inserting Fuse Block and Cover Assembly
Model 1305 MultiVolume Pycnometer Selecting the Voltage
Gas Supply
The helium or other gas used, whatever its source, should be regulated to a pres-sure between 140 and 170 kPa (20 and 25 psig) by a reliable leak-tested regula-tor. Suitable regulators are available from Micromeritics. Refer to Chapter 5 for ordering information. The regulator outlet should be attached with metal tubing to the MultiVolume Pycnometer 1305 on the righthand side of the instrument to the fitting closest to the power entranc; a roll of copper tubing with fittings is sup-plied in the accessory kit for this purpose.
It is easy to overtighten the fitting that admits analysis gas to the Multivolume Pycnometer 1305. Doing so can collapse the copper tubing, damage the fitting, and actually cause a leak. Tighten each nut solidly finger-tight and then add one-quarter turn with a wrench.
Micromeritics uses and recommends the use of research-grade gases. If unobtain-able, the highest purity gas conveniently available will probably prove satisfactory. Upon first applying gas pressure, verify that no gas flow is occurring when the FILL valve on the front panel of the instrument is closed. Flow may indicate that the inlet connection was improperly made or that enough pressure was applied to open the protective relief valve in the instrument.
CHAPTER 3
OPERATION
•
Controls and Components
•
Startup
•
Preparing and Weighing the Sample
•
Performing an Analysis
•
Calculating the Sample Volume, Density, and
Specific Volume
•
Verifying Calibration
•
Calibrating the Analyzer
OPERATION
The Multivolume Pycnometer 1305 permits the rapid determination of sample vol-umes. This chapter provides information and instructions to assist you in obtain-ing maximum accuracy and productivity in runnobtain-ing samples, calculatobtain-ing results, and ensuring accurate calibration of the instrument.
Controls and Components
Before operating the Model 1305 Pycnometer, you should become familiar with its controls and components. All operating controls for the Model 1305 Pycnome-ter are on the front panel (shown in the following illustration). The gas, vacuum, and power connections are located on the right side panel.
Controls
ON/OFF switch Provides electrical power to the analyzer. Lighting of the numbers on the pressure display indicates that AC power is present.
ZERO adjustment knob
Allows you to zero the pressure reading following the venting of the internal volumes to the atmosphere This control is a 10-turn precision potentiometer allow-ing you to set the zero to the nearest 0.001 psig with a range of more than ± 0.300 psig.
Before using this adjustment, ensure that:
• the FILL valve is in the CLOSE position
• the PREP/TEST valve is in the TEST position
• the VENT valve is in the OPEN position
• the pressure has stabilized >5/<5 and >35/<35
valves
Allow you to alter the size of the expansion volume to provide the best match and, therefore, the best reso-lution and sensitivity for each of the 150-, 3, and 5-cm3 ranges.
• 150-cm3 range: Do not use a sample chamber in-sert. Set the >5/<5 valve to >5 and the >35/<35 valve >35. Expansion volumes 1, 2, and 3 are then connected together and used as the one largest ex-pansion volume, VEXP150.
• 35-cm3 range: Use the 5.08 cm (2 in.) diameter by 7.62 cm (3 in.) height sample chamber insert with the largest well. Set the >5/<5 valve to >5 and the >35/<35 valve <35. Expansion volumes 1 and 2 are then connected together and constitute the intermedi-ate expansion volume, VEXP35.
• 5-cm3 range: Use the 5.08 cm (2 in.) diameter by 7.62 cm (3 in.) height sample chamber insert with the smaller well. Set the >5/<5 valve to <5. The po-sition of the >35/<35 valve has no effect, but for consistency set it to <35. Expansion volume 1 alone is then used and is designated VEXP5.
FILL valve Allows you to admit helium or other gases into the in-strument for purging or charging prior to a volume measurement.
VENT valve Allows you to open a discharge path for the purge gas, establish the zero psig starting condition in the sample chamber and expansion volume, or open a path to any vacuum applied to the discharge port.
Controls and Components Model 1305 MultiVolume Pycnometer
FILL RATE control valve
Controls the rate of pressure build when charging the sample chamber or the flow rate when purging a sam-ple during preparation. A judicious balance of the ap-plied pressure (say, 22 psig) along with this setting permits nearly the same charging pressure to be reached during test, ensuring maximum reproducibil-ity. Turn the valve clockwise to reduce the flow rate; counterclockwise to increase it. A stop will be reached just before flow entirely ceases. VENT RATE
control valve
Controls the rate of flow when the VENT valve is suddenly opened, especially if a vacuum is applied to the discharge port. Proper setting of this control pre-vents fine powders from being pulled from the sam-ple cup and deposited in the valves and tubing of the instrument.
Always begin with this control fully clockwise if fine powders are to be measured.
PREP/TEST valve Divides the instrument’s internal volume into two parts: the sample cell volume and the expansion vol-ume. These two volumes are isolated and the expan-sion volume is sealed when the valve is in the PREP position. The sample cell may then be charged with gas under pressure without altering the pressure in the expansion volume.
When placed in the TEST position, the expansion vol-ume is connected to the sample chamber volvol-ume and a continuous flow-through path is established to per-mit purging. The resulting pressure then depends upon the volume ratios and initial pressures in the spaces.
Components
Pressure display Displays the current pressure with a range of 0.0 to 19.999 psig. The calibration is not exact as the most important consideration is linearity rather than abso-lute accuracy.
Sample chamber The sample chamber is made of stainless steel and contains gas inlet and outlet holes to permit a flow-through path for ease of purging. A 5.08-cm (2-in.) di-ameter and 7.62-cm (3-in.) depth (cap in place) results in a volume of somewhat over 154 cm3. Pow-dered samples placed directly in the chamber would obviously clog the outlet tubing and would be diffi-cult to recover from the chamber. A light-gauge re-movable sample cup is provided to permit easy handling of samples. This cup reduces the sample ca-pacity for powders to about 120 cm3 since it must be
smaller than the chamber diameter. Sample chamber
insert
Accuracy of the MultiVolume Pycnometer 1305 tends to be a fixed fraction of the maximum sample cham-ber volume whether filled with sample or not. Sample chamber inserts are provided to create chambers of 35-and 5-cm3 nominal volumes so that small samples can
be run with high resolution and accuracy. These sam-ple chamber inserts, especially the 5-cm3 one, are high precision parts in the form of cylinders approxi-mately 5.08 cm (2 in.) in diameter and 7.62 cm (3 in.) in length. Cylindrical wells are machined in the upper faces to create the sample chambers. Enough clearance is left between the sample chamber wall to permit free flow of the gas during purging. Sample cups Light-gauge removable sample cups also made of
alu-minum are provided to fit closely in the machined wells in the top of the sample chamber inserts. These will hold bulk volumes of 31.25 cm3 and 3.933 cm3 for the 35-cm3 nominal range and 5-cm3 nominal range, respectively.
A bent end probe is provided to facilitate easy re-moval of the sample cups. This probe is to be used in conjunction with small holes in the upper lip of the sample cups to lift the cup to a point where it can be grasped by fingers.
Controls and Components Model 1305 MultiVolume Pycnometer
Calibration Volume Four precision balls (volumes) are supplied with the instrument to be used as high accuracy calibration standards.
• one 2.4250-cm3 ball of 0.6563-in. diameter for use with the 5-cm3 sample volume range
• one 16.758-cm3 ball of 1.2500-in. diameter for use with the 35-cm3 range
• two 25.49-cm3 balls (50.97-cm3 total) of 1.4375-in. diameter for use with the 150-cm3 range.
These volumes should be kept clean and maintained as near the temperature of the instrument as possible while in use.
Sample Chamber Cap and Sealing O-ring
Permits opening and closing of the sample chamber with volume variations held to the microliter or less range. The flat surface of the sealing plug mates with a matching flat of the lip of the sample cup to pro-vide a precise metal-to-metal stop. These surfaces must be kept scrupulously free of particles, especially with the 5-cm3 range, if the best instrument perform-ance is to be achieved. The sealing plug is fitted with a 2 x 1-7/8 x 1/16-in. Buna-NTM
o-ring which makes the seal. This o-ring should be coated with a thin layer of vacuum grease. It and all the surfaces it touches or wipes must be maintained free of particles. Two spare o-rings are included in the accessory kit. Pressure transducer The pressure transducer is a 25-psig unit of ±0.1% of
full scale accuracy. It is used only up to 20 psig in the instrument. It will indicate vacuum down to about -5 psig before showing a constant reading. Even though it will not indicate vacuum below -5 psig, it is not harmed by application of high vacuums. It is lo-cated in the electronics enclosure on the other side of the wall from the filter assembly. This transducer type has been chosen for its excellent linearity, a factor es-sential to the accurate operation of the Model 1305 MultiVolume Pycnometer.
Overpressure Relief Valve
Provided for protection against damage to the instru-ment. The overpressure relief valve is connected di-rectly at the gas input connection and is set at the factory to open when the pressure reaches 25 ±1 psig. The setting is altered by means of a set screw at its discharge end. The setting should be changed only if an accurate pressure gauge is available and the relief point is known to be incorrect. Resealing of this valve requires that the gas inlet pressure be reduced to under 20 psig before leaking will stop.
Filter The filter is a large area, fritted metal disk installed just downstream of the sample chamber. Its function is to protect the transducer, valves, and expansion vol-umes against contamination by powder particles which could cause leaks, volume changes, and pres-sure instability. It is mounted on the rear wall of the plumbing compartment in a cylindrical assembly. The filter should be cleaned or replaced only after confirm-ing that powder has been drawn into the system. A spare filter is included in the accessory kit.
Gas inlet and Gas outlet/vacuum connection
The gas inlet is a 1/4-in. diameter threaded brass con-nection designed to accept 1/8-in. metal tubing se-cured by a Swagelok®
fitting with brass ferrules. The gas outlet/vacuum connection is a 0.300-in. di-ameter brass barbed fitting intended for use with 0.250-in. inside diameter rubber or plastic tub-ing. Both fittings are located on the righthand side of the instrument near the power entrance. The gas out-let/vacuum connection is closest to the front of the in-strument.
Power entrance Power enters the instrument through this assembly lo-cated on the righthand side of the instrument. An inter-national power connector of the IEC-type is included and requires a detachable power cord which is in-cluded in the accessory kit.
A small circuit card permits selection of any operating voltage. A built-in fuse provides protection; the fuse should be a 0.5 Ampere slow-blow type for voltages of 100 to 120 volts and a 0.25 Ampere slow-blow type for 200 to 240 volts. Refer to Chapter 2 for in-structions on voltage selection and fusing.
Controls and Components Model 1305 MultiVolume Pycnometer
DC power supply The DC power supply is located in the electronics compartment and is accessible by removing the rear panel (detach power cord first). It is a standard OEM open-frame unit wired to deliver +24 VDC and +5 VDC to power the transducer and pressure display, re-spectively.
Startup
The following procedure should be followed when the Multivolume Pycnometer 1305:
• is being used for the first time
• has not been used for several days
Before beginning this procedure, ensure that the gas supply has been con-nected and that the proper voltage is being supplied to the analyzer. (Re-fer to Chapter 2 for voltage requirements.)
1. Turn on the analyzer and observe that the pressure display illuminates. 2. Remove the sample chamber cap and inspect the chamber; clean the
cham-ber if particles or powders are present.
3. Using a clean, lint-free cloth or tissue, wipe the upper rim and the upper in-side surface of the chamber to remove any particles or buildup of grease from the O-ring.
4. Inspect the bottom of the sample chamber cap; clean the sealing plug and its flat surface.
5. Ensure that the O-ring is undamaged and that the grease film is clean and adequate. If in doubt about either, replace them.
6. Install the desired sample chamber insert as follows:
Be sure the insert is clean; use a lint-free cloth if cleaning is required.
If you are using the 150-cm3 range, an insert is not required. If the cham-ber is empty, proceed to step 8. If an insert is in the chamcham-ber, proceed to step 7 for instructions on removing it.
a. Place the VENT valve in the OPEN position, then turn the VENT RATE control knob several turns counterclockwise to open it.
b. Place the insert into the sample chamber; a gentle push may be used if needed. Be sure the insert is properly aligned with the sample chamber before pushing.
c. Proceed to step 8.
Startup Model 1305 MultiVolume Pycnometer
7. If analysis is to be performed in the 150-cm3 range and an insert is in the chamber, perform the following steps to remove it:
a. Place the VENT valve in the OPEN position, then turn the VENT RATE control several turns counterclockwise to open it.
b. Place the FILL valve in the OPEN position. This allows the gas pressure to ease the insert up gently until it can be grasped. Do not force the in-sert to move rapidly; it will come out easily if allowed a few seconds. 8. Ensure that the FILL valve is in the CLOSE position.
9. Place the PREP/TEST valve in the TEST position.
10. Place the >5/<5 valve in the >5 position and the >35/<35 valve in the >35 position.
11. Ensure that the VENT valve is in the OPEN position. 12. Replace the sample chamber cap.
13. Place the FILL valve in the OPEN position. Allow gas to flow through the instrument for approximately five minutes. Use a mid-range setting on the FILL RATE and VENT RATE valves.
14. Place the FILL valve in the CLOSED position; wait until the pressure read-ing falls and becomes stable.
15. Adjust the ZERO control to indicate +0.000.
16. Place the valve in the position appropriate for the sample volume range (and insert) you plan to use (refer to the following illustration):
• Under 5 cm3, place the >5/<5 valve in the <5 position and the >35/<35 valve in the <35 position
• 5 to 35 range, place the >5/<5 valve in the >5 position and the >35/<35 valve in the <35 position
• 35 to 150 range, place the >5/<5 valve in the >5 position and the >35/<35 valve in the >35 position
Figure 3-1. Pycnometer Settings for Optimum Results
17. Place the PREP/TEST valve in the PREP position. The instrument is now ready to run samples.
Nominal Sample Volume (cm3)
Insert in Sample
Chamber Valve Orientation
Under 5
5 to 35
35 to 150
Startup Model 1305 MultiVolume Pycnometer
Preparing and Weighing the Sample
Sample preparation consists of:
• obtaining a representative sample of the material
• removing any vapors (especially water) which would interfere with the pressure ratios measured by the instrument
• placing it in an appropriate sample cup
Weighing of the sample is required if density or specific volume is to be com-puted. This is best done after vapor removal and most often should be done after running the sample. Weighing and recording the weight of the empty sample cup will permit the net weight of the filled sample cup to be calculated later.
Porous samples which trap helium may cause buoyancy and weight drift so care should be exercised to purge porous samples thoroughly with dry air or nitrogen if the highest degree of accuracy is required.
Performing an Analysis
The following step-by-step procedure assumes that the >5/<5 valve and the >35/<35 valve have been set to the desired range, that the matching insert is in place or available, and that the matching sample cup contains the sample to be analyzed. Appendix B contains a sample data sheet for organizing and recording data.
1. Ensure that the FILL valve is in the CLOSE position. 2. Place the PREP/TEST valve in the PREP position. 3. Ensure that the VENT valve is in the OPEN position. 4. Remove the sample chamber cap.
5. Remove any previous sample and/or insert and cup. 6. Place the new sample and/or insert into the chamber. 7. Replace the sample chamber cap; securely tighten. 8. Close the VENT RATE and FLOW RATE valves. 9. Place the FILL valve in the OPEN position.
10. Open the VENT RATE and FLOW RATE valves to approximately mid-range.
If your sample is a light powder, open the valve slowly to avoid splashing of the powder.
11. Air and vapors trapped within pores, crevices, or among the pieces of the sample will be removed from the sample by a prolonged purge in this condi-tion. However, these gases are much more rapidly removed by alternately in-creasing and dein-creasing the gas pressure in the sample chamber. Place the VENT valve in the CLOSE position and allow the pressure to rise.
12. When the indicated pressure has risen to, say, 16 to 18 psi, close the FILL valve and open the VENT valve. When the indicated pressure then drops to, say, 1 to 0.5 psi, close the VENT valve and open the FILL valve. Repeating this procedure 8 or 10 times adequately purges from most powdered or po-rous samples whatever gases they originally entrained and replaces them with the “working” gas, i.e., the helium or dry nitrogen.
13. Place the FILL valve in the CLOSE position and the VENT valve in the OPEN position.
Performing an Analysis Model 1305 MultiVolume Pycnometer
14. Place the PREP/TEST valve in the TEST position.
15. Allow the pressure to fall to zero and stabilize, correcting the pressure dis-play with the ZERO control as necessary.
16. Place the PREP/TEST valve in the PREP position, ensuring that the zero does not shift. If a shift occurs, return the valve to the TEST position and re-peat Step 15.
17. Place the VENT valve in the CLOSE position, disregard any change of pressure.
18. Place the FILL valve in the OPEN position and fill the chamber to 19.500
±0.200 psig as shown on the pressure indicator.
19. Place the FILL valve in the CLOSE position and allow the pressure to equili-brate; record it as P1. Short times (approximately 15-30 sec) give best results
for most samples.
20. Immediately place the PREP/TEST valve in the TEST position and allow the pressure to equilibrate; record it as P2. Short times (approximately 15-30
sec) give best results for most samples.
21. Place the VENT valve in the OPEN position. If light powders are being ana-lyzed, first close the VENT RATE valve (turn counterclockwise); then gradu-ally open it as the pressure approaches zero.
22. Return to Step 15 if multiple determinations are to be made on this sample. 23. Remove the sample cup using the bent-end probe provided in the accessory
kit. Hook the probe in the hole in the upper lip of the cup and pull upward until the cup can be grasped with fingers.
• If a new sample is to be analyzed, return to Preparing and Weighing the Sample.
• If the instrument is to remain idle for an extended period (days), close the sample chamber and shut off the helium supply. Refer to Turning Off the Analyzer in this chapter for the proper shutdown procedure.
When all samples have been run, proceed to the next section for instructions on calculating the results from the pressures recorded.
Calculating the Sample Volume, Density, and Specific Volume
The general equation for computing the sample volume is
VSAMP = VCELL −
VEXP
P1⁄P2− 1
where
VSAMP = the sample volume to be found,
VCELL = the empty volume of the sample cell with the empty sample cup
in place,
VEXP = the expansion volume added when the PREP/TEST valve is
in the TEST position,
P1 = the charge pressure (recorded in Step 18 of Performing an Analysis, and
P2 = the pressure after expansion (recorded in Step 19 of Performing
an Analysis.
Each range has its values for VCELL and VEXP; these are provided on the
calibra-tion sheet for the instrument. Numerical suffixes are added to each to identify the range to which they pertain; for example, VEXP35 is the expansion volume used
on the 35-cm3 range.
A sample data sheet to help facilitate computations is included in Appendix B. A detailed derivation of the equation is found in Appendix A. The computer pro-gram in Appendix C may be used to automate sample computation.
Density is defined as the weight per unit volume and will usually be computed as
ρSAMP =
WSAMP
VSAMP =
Gross Weight −Cup Weight VSAMP
where
ρSAMP = sample density, WSAMP = sample weight, and
VSAMP = sample volume.
Calculating the Sample Volume, Density, and Specific Volume Model 1305 MultiVolume Pycnometer
Specific volume is defined as the volume per unit weight and is computed as USAMP = VSAMP WSAMP = 1 ρSAMP where
USAMP = sample specific volume.
Verifying Calibration
Two quick checks may be made to determine if the instrument needs to be recali-brated.
• the zero offset or additive errors of the instrument
• the scale factor errors (assuming that the zero offset errors are negligible) These checks should be made if changes have occurred in the inner parts of the instrument, the sample chamber or cap, the sample inserts, the sample cups, or if the temperature differs appreciably from the temperature at the time of the pre-vious calibration.
Zero Offset
Verify the zero offset by running the empty sample cup and calculating the re-sult. The error from zero should be less than 0.2% of the full scale range.
Scale Factor
Verify the scale factor by placing the calibration volumes (balls) in the sample cup and running them as if they were samples and computing the results. The vol-ume error from the values supplied on the calibration data sheet should be less than 0.2% of the full scale range. The calibration data sheet and the calibrated volumes are supplied in the accessory package and are designated as VCALIB with
numerical suffixes to indicate the range.
If excessive errors are revealed during verification, perform the calibration proce-dure in the following section to establish new, accurate values for the VCELL and
VEXP instrument constants.
Calibrating the Analyzer
Definition of Volumes to be Calibrated
Illustrated here is a schematic diagram of the Multivolume Pycnometer 1305 with labels added to facilitate the discussion which follows. Refer to it as the follow-ing is read.
Figure 3-2. Schematic of 1305 MultiVolume Pycnometer
Operation of the instrument depends upon first charging the volume between the FILL valve and the VENT valve (VSAMP) to an elevated gas pressure (P1), then
rotating the PREP/TEST valve to expand the pressure into a precisely known added volume (VEXP). The final pressure (P2) then is indicative of the sample
vol-ume since larger sample volvol-umes reduce by displacement the amount of gas in the initial charge and result in lower final pressures.
Calibrating the Analyzer Model 1305 MultiVolume Pycnometer
The following six calibrated volumes must be known for each instrument before sample runs can be made:
VCELL5 The sample cell and void volume between the FILL valve and the VENT valve when the PREP/TEST valve is in the PREP position, the 5-cm3 sample chamber insert is in place, and the empty 5-cm3 sample cup is in place.
VCELL35 The sample cell and void volume between the FILL valve and the VENT valve when the PREP/TEST valve is in the PREP position, the 35-cm3 sample chamber insert is in place, and the empty 35-cm3 sample cup is in place.
VCELL150 The sample cell and void volume between the FILL valve and the VENT valve when the PREP/TEST valve is in the PREP position and the empty 150-cm3 sample cup is in place.
VEXP5 The volume added to VCELL5 when the PREP/TEST valve is in the
TEST position while the >5/<5 valve is in the <5 position.
VEXP35 The volume added to VCELL35 when the PREP/TEST valve is rotated
to TEST while the >5/<5 valve is in the >5 position and the >35/<35 valve is in the <35 position.
VEXP150 The volume added to VCELL150 when the PREP/TEST valve is in the
TEST position while the >5/<5 valve is in the >5 position and the >35/<35 valve is in the >35 position.
The instrument is always calibrated on each range using a standard volume, pref-erably the precision ball bearing which fills the maximum possible fraction of the sample cup. The labels VCALIB5, VCALIB35, and VCALIB150 will be used to identify
these. When using the precision ball bearings provided with the instrument: VCALIB5 = 2.4250 cm3;
VCALIB35 = 16.758 cm3; and
VCALIB50 = 2 x 25.49 cm3 = 50.97 cm3
Sample volumes will be labeled VSAMP. The pressure to which the system is
in-itially charged will always be P1 and the pressure after expansion will always be
P2. Asterisks or other symbols may be added to differentiate P1, P2 pairs taken
with differing sample chamber contents. A detailed derivation of the calibration theory and equations is presented in Appendix D.
Calibration Procedure
This procedure measures VCELL5, VCELL35, VCELL150, VEXP5, VEXP35, and VEXP150
as the average of three repeated determinations. A data sheet is provided in Ap-pendix B from which results can be computed by using the calculator workshee also provided in Appendix B.
This procedure must be used on all new instruments; or after any changes to the sample chamber, tubing, fittings, sample cup or sample chamber inserts have oc-curred which might alter their volumes, and whenever the operating temperature differs appreciably from the nominal 72 oF calibration temperature.
When the following steps call for a “sample run,” perform the steps outlined in Performing an Analysis (located in a previous section of this chapter).
1. Connect electrical power to the instrument and allow it to begin a 15-minute warmup.
2. Place the three empty sample container cups, all the VCALIB standard vol-umes, and the two sample chamber inserts alongside the instrument to ther-mally equilibrate. Wipe them with a lint-free cloth or tissue to remove particles or oils.
3. Connect helium regulated at 138 to 152 kPa (20-22 psig) to the helium inlet (threaded fitting nearest the back of the instrument on the righthand side). 4. Place the >5/<5 valve in the <5 position.
5. Place the >35/<35 valve in the <35 position.
6. Install the 5-cm3 chamber insert and place the empty 5-cm3 sample cup in it. Make three sample runs and record the pressures in the appropriate place on a copy of the data sheet in Appendix B.
7. Place the VCALIB5 standard volume in the 5-cm3 sample cup and make three
sample runs. Record the VCALIB5 and pressures on the data sheet.
8. Place the >5/<5 valve in the >5 position and the >35/<35 valve in the <35 position.
9 Install the 35-cm3 chamber insert and place the empty 35- cm3 sample cup in it. Make three sample runs and record the pressures on the data sheet. 10. Place the VCALIB35 standard volume in the 35-cm3 sample cup and make
three sample runs. Record the VCALIB35 and pressures on the data sheet. 11. Place the >5/<5 valve in the >5 position and the >35/<35 valve in the >35
position.
Calibrating the Analyzer Model 1305 MultiVolume Pycnometer
12. Remove the 35-cm3 sample chamber insert and cup, then install the empty 150-cm3 sample cup. Make three sample runs; record the pressures on the data sheet.
13. Place the VCALIB150 standard volume in the 150-cm3 sample cup and make
three sample runs. Record the VCALIB150 and the pressures on the data sheet.
14. Use a hand calculator to calculate the internal volumes or the calculator worksheet provided in Appendix B. Record the volumes on the data sheet along with the instrument serial number, the date, and the name of the operator.
Turning Off the Analyzer
Perform the following steps to properly shut down the Model 1305 Pycnometer: 1. Remove any sample from the sample chamber and replace the sample cap. 2. Place the >5/<5 valve in the >5 position and the >35/<35 valve in the >35
position.
3. Place the VENT valve in the OPEN position.
4. Admit helium or other dry gas by opening the FILL valve; purge for at least one minute. Then placee the FILL valve and the VENT valve in the CLOSE position.
5. Turn off the power switch if the instrument will not be needed within the next 24 hours.
6. Close the tank valve or other main supply valve for the gas to avoid loss should the tubing accidentally be ruptured.
The instrument can be left in this state indefinitely and still be ready to run sam-ples in minutes after restart.
CHAPTER 4
TROUBLESHOOTING
•Unstable Pressures
•Nonreproducible Results
•Incorrect Results
•Pressure Indicator
TROUBLESHOOTING
Perform the checks and tests described in this section before seeking further assis-tance. Contact your local service representative or the factory when unsuccessful in resolving the difficulty.
Unstable Pressures
Falling Pressures
Falling temperatures or rising ambient pressure can cause the indicated pressure to continue to fall beyond the expected transients following filling and expansion. The effects are usually minor in a comfortable room and under normal ventilation conditions due to the speed with which sample runs are accomplished.
The most serious cause of falling pressures is a leak. The first leak check should be that of the sample cap O-ring and the sample chamber surface against which it seals. Inspect the O-ring to determine whether it is damaged; replace it if neces-sary. Clean the sealing surfaces and lightly grease the O-ring with vacuum grease. To isolate system leaks:
1. Place the PREP/TEST valve in the PREP position, the >5/<5 valve in the <5 position, and the >35/<35 valve in the <35 position.
2. Close the VENT valve.
3. Open the FILL valve. Allow the pressure to increase to approximately 19.500 psig, then close the FILL valve.
If the pressure remains stable, no leak exists in the sample chamber and asso-ciated tubing and components.
4. Place the PREP/TEST valve in the TEST position
If the pressure remains steady, no leaks exist in the VEXP5 volume or associ-ated positions.
5. Place the >5/<5 valve in the >5 position; observe the pressure stability. If the pressure remains steady, no leaks exist in the volumes and tubing be-tween the >5/<5 and the >35/<35 valves.
6. Place the >35/<35 valve in the >35 position.
If the pressure remains steady, no leak exists in the largest increment of ex-pansion volume.
Many samples such as organic materials or closed cell foam plastics allow helium or other gases in the initial gas charge to slowly diffuse into the interior of the sample. To determine whether the sample is responsible for any discrepancy, re-move the sample and re-test with the chamber empty. While some such samples may be run and useful information produced, they may require the development of special procedures.
Samples colder than the instrument, especially those that are massive or non-po-rous can cause falling pressures. Always try to store samples in the vicinity of the instrument for a time sufficient to produce thermal equilibration before testing.
Rising Pressures
Pressures which rise after initial charging with gas are most frequently caused by the presence of condensible vapors (usually water) on the sample. Continued purg-ing of the sample, vacuum treatment, or repeated runs usually clear up this prob-lem for most samples.
A leak through the FILL valve may cause rising pressures. Removal of inlet pres-sure would then cause the direction of the leak to reverse, confirming the source. Samples warmer than the instrument, especially those that are massive or non-po-rous, can cause rising pressures until temperature equilibration takes place. Al-ways try to store samples near the instrument for a sufficient period of time to allow thermal equilibration.
Nonreproducible Results
Unstable pressures are the most common cause of lack of reproducibility. Pres-sures should stabilize to better than 0.005 psig per minute before readings are taken if the specified accuracy is to be achieved. Refer to the previous sections for assistance in stabilizing pressures.
Timing of pressure readings is important. The charging pressure, P1 should be re-corded just before the PREP/TEST valve is placed in the TEST position. The ex-pansion pressure, P2 should be recorded as soon afterward as the pressure has stabilized; should it not stabilize within 30 seconds, some difficulty exists.
Particles on the rim of the sample chamber or on the mating surface of the cham-ber cap cause a volume change of the chamcham-ber and a corresponding error in the sample result. Inspect to be sure that firm metal-to-metal contact is being made, and that the cap has been fully seated.
Nonreproducible Results Model 1305 Multivolume Pycnometer
Purging is important to remove all air following opening and reclosing of the sam-ple chamber. Air, especially moist air, behaves differently than helium or dry ni-trogen and will cause the sample results to vary.
Zeroing must be done with care and accomplished as shortly before charging with gas pressure as feasible. There is some difference between +0.000 and -0.000; one or the other should be used consistently where absolutely best results are sought.
Heat and moisture from the hands can cause significant effects. Use gloves or a cloth when handling the sample cap and samples to help minimize these effects. Using charging pressures, P1 outside the 19.500 ±0.200 psig range will cause small but systematic variations in results due to the small amount of unavoidable non-linearity in the pressure transducer.
Incorrect Results
Consistent, but incorrect measured volumes may be due to one or more of the fol-lowing causes.
The >5/<5 valve or the >35/<35 valves are in the wrong position for the range in use, or an incorrect sample chamber insert is being used. Refer to Chapter 3 for information on valve positions and inserts.
Operation outside the 67-77 °F range on the 5-cm3 full-scale range may require recalibration at the new temperature. Refer to Calibrating the Analyzer in Chap-ter 3.
The calibration may be invalid due to disassembly of tubing, alteration of sample cups, exchange of sample cups or sample chamber inserts, or not using sample cups when the instrument calibration was made with them in place. A sample chamber cap which has changed in its seating will alter the calibration. Particles on the sample chamber floor can cause the sample chamber inserts to protrude and strike the cap, altering the seating, and causing errors. Refer to Calibrating the Analyzer in Chapter 3 for instructions on checking and correcting the calibra-tion.
Review carefully the computation of sample results and calibra tion constants to ensure that errors are not being made. Confirm the correctness of calibration vol-ume standards through measurements or other independent tests.
Use of charging pressure, P1 differing from the 19.500 ±0.200 psig will require re-calibration to compensate for any slight nonlinearity of the pressure transducer.
Samples of high specific surface area may contribute an error due to a layer near the surface that is partly depleted of gas molecules termed the annulus volume. Volume errors in the range of 0.005 cm3/g for powders with specific surface areas of the order of 100 m2/g or 0.05 cm3/g for 1000 m2/g specific surface area powders are possible. The user is advised to undertake a special examination of this phenomenon so that precise computations may be made for the gas and pow-der system in use.
Use of gases other than helium will lead to somewhat less accurate results. Dry nitrogen is usually satisfactory but, in general, the higher the liquefaction tempera-ture and the larger the molecular weight of a gas, the poorer the accuracy since nonideal behavior becomes more pronounced.
Pressure Indicator
Fails to Illuminate
Verify that the power cord is plugged into an energized outlet of the proper volt-age and firmly seated in the power entrance connector of the instrument. Operate the power switch to the ON position. Unplug the power cord from the instrument and remove the fuse and inspect it. If these measures do not reveal the source of the problem, again unplug the power cord and remove the rear panel of the instru-ment and inspect the connectors inside to determine if any have loosened. Con-tact your local service representative in the problem persists.
Constantly Indicates Nearly the Same Pressure
During evacuation of samples, the pressure transducer will be internally limited to an indication of about 1/3 of the positive full-scale range or about -5.000 psig even though the reading should be -14.700 psig. Although the transducer was in-tended for positive pressure indications, this will cause no harm to it.
A reading which does not respond to the FILL valve or VENT valve operation most likely indicates a defective pressure transducer, pressure indicator, or power supply. Contact your local service representative for resolution.
Pressure Indicator Model 1305 Multivolume Pycnometer
Slow Return to Zero Pressure Upon Venting
The VENT RATE control may be set too far clockwise. Increase the flow rate by turning it counterclockwise one or more turns.
Some samples such as organics and plastic foams may trap gas and slowly re-lease it when the pressure is reduced. Remove the sample or permit it to evacu-ate long enough for the trapped gases to diffuse out.
Powders drawn into the internal spaces of the instrument may clog the filter lo-cated on the rear wall of the mechanical section. Clean or replace this filter. Un-plug the instrument and turn off the gas supply before removing any panels.
CHAPTER 5
ORDERING INFORMATION
Accessories for the Model 1305 MultiVolume Pycnoemter can be ordered through our Customer Order Entry Department, (707) 662-3636. Please use the informa-tion provided below.
Part Number Description
004-16006-00 Vacuum grease, 25 grams
003-51135-00 Fuse, 3 AG, 0.5 A, Slow-Blow, for 100/120 V mains 003-51141-00 Fuse, 3 AG, 0.25 A, Slow-Blow, for 200/240 V mains 004-25549-00 Reducer, 1/8-in. (0.32-cm) compression fitting to 1/4-in.
(0.64-cm) tube
004-25078-00 O-ring, Buna-N, for sample chamber cap 004-27039-00 Gasket, filter
004-25103-00 Ferrule (front), Teflon, for 1/4-in. (0.64-cm) OD tubing 004-25104-00 Ferrule (rear), Nylon, for 1/4-in. (0.64-cm) OD tubing 004-25198-00 Ferrule (front), brass, for 1/8-in (0-32-cm) OD tubing 004-25199-00 Ferrule (rear), brass, for 1/8-in. (0.32-cm) OD tubing 135-25805-00 Sample cup, 5 cm3
135-25804-00 Sample cup, 35 cm3 135-25812-00 Sample cup, 150 cm3 135-25803-00 Insert, for 5-cm3 sample cup 135-25802-00 Insert, for 35-cm3 sample cup 135-25813-00 Calibration volume, 2.43 cm3 130-25658-00 Calibration volume, 16.76 cm3 135-25815-00 Calibration volume, 25.49 cm3
004-62230-58 Gas regulator, CGA 580 fitting, 0-30 psig
004-33601-00 Expansion kit; adds an additional outlet to the gas regulator
135-42802-00 Operator’s manual
APPENDIX A
THEORY
The Multivolume Pycnometer 1305 is a gas displacement pycnometer, a type of instrument which measures the volume of solid objects of irregular or regular shape whether powdered or in one piece. A greatly simplified diagram of the in-strument is shown in Figure A1-1.
Assume that both VCELL and VEXP are at ambient pressure Pa, are at ambient temperature Ta, and that the valve is then closed. VCELL is then charged to an ele-vated pressure P1. The mass balance equation across the sample cell, VCELL is
P1 (VCELL - VSAMP) = nCRTa (1)
where
nC = the number of moles of gas in the sample cell, R = the gas constant, and
Ta = the ambient temperature.
Figure A1-1. Simplified Block Diagram of MultiVolume Pycnometer 1305
The mass equation for the expansion volume is
PaVEXP = nERTa . (2)
where
nE = the number of moles of gas in the expansion volume.
When the valve is opened, the pressure will fall to an intermediate value, P2, and the mass balance equation becomes
P2 (VCELL - VSAMP + VEXP) = nCRTa + nERTa (3) Substituting from equations (1) and (2) into (3):
Pn (VCELL - VSAMP + VEXP) = P1 (VCELL - VSAMP) + PaVEXP (4) or
(P2 - P1)(VCELL - VSAMP) = (Pa - P2)VEXP (5) then
VCELL− VSAMP =
Pa−P2
P2− P1
VEXP (6)
Adding and subtracting Pa in the denominator and rearranging gives
−VSAMP = −VCELL+
(Pa−P2) VEXP
(P2− Pa)−(P1− Pa)
(7)
Dividing by (Pa - P2) in both the numerator and denominator
VSAMP = VCELL− VEXP −1− P1− Pa Pa−P2 (8) or VSAMP = VCELL− VEXP P1− Pa P2− Pa − 1 (9)
Since P1, P2, and Pa are expressed in equations (1) through (9) as absolute pres-sures and equation (9) is arranged so that Pa is subtracted from both P1 and P2 before use, new P1g and P2g may be redefined as gauge pressures
Appendix A Model 1305 MultiVolume Pycnometer
P1g = P1 - Pa (10)
P2g = P2 - Pa (11)
and equation (9) rewritten as
VSAMP = VCELL− VEXP P1g P2g − 1 (12)
Equation (12) then becomes the working equation for the MultiVolume Pycnome-ter 1305. Calibration procedures are provided to dePycnome-termine VCELL and VEXP and the pressures are measured by a gauge pressure transducer. Provisions are made for conveniently charging and discharging gases at controlled rates, for optimizing the relative sizes of the sample chambers and expansion volumes, and for cleans-ing the samples of vapors which would render equations (1), (2), and (3) inade-quate to describe the pressure behavior.
APPENDIX B
FORMS
MultiVolume Pycnometer 1305 Sample Data Sheet
Sample Identification: __________________________________________________________________ ____________________________________________________________________________________
Gross Weight: ______________ Full Scale Range: ______________ Cup Weight: ______________ Minutes Purge: ______________ Net Weight: ______________ Minutes Vacuum: ______________
VCELL: ______________ VEXP: ______________ VSAMP = VCELL − VEXP P1 P2 − 1 P1 P2 VSAMP 1. ______________ _______________ _______________ 2. ______________ _______________ _______________ 3. ______________ _______________ _______________ 4. ______________ _______________ _______________ 5. ______________ _______________ _______________ 6. ______________ _______________ _______________ 7. ______________ _______________ _______________ 8. ______________ _______________ _______________ 9. ______________ _______________ _______________ 10. ______________ _______________ _______________ VSAMP Sum _______________ VSAMP Average _______________ Density = Net Weight
VSAMP Average
Data Sheet for Internal Volume Calibration
MultiVolume Pycnometer 1305
Pressures = psig; Volumes = cm3
5-cm3 Range
(empty sample cup) (VCALIB5 in place)
1 P1 ____________ P2 ___________ P1 _________________ P2 ____________ 2 P1 _________________ P2 ___________ P1 ___________ P2 ____________ 3 P1 _________________ P2 ___________ P1 ___________ P2 ____________
VCALIB5 = _______________
Computed Results from Above Data: VCELL5 = _______________ VEXP5 = _______________
35-cm3 Range
(empty sample cup) (VCALIB5 in place)
1 P1 ____________ P2 ___________ P1 _________________ P2 ____________ 2 P1 _________________ P2 ___________ P1 ___________ P2 ____________ 3 P1 _________________ P2 ___________ P1 ___________ P2 ____________
VCALIB35 = _______________
Computed Results from Above Data: VCELL35 = _______________ VEXP35 = _______________
150-cm3 Range
(empty sample cup) (VCALIB5 in place)
1 P1 ____________ P2 ___________ P1 _________________ P2 ____________ 2 P1 _________________ P2 ___________ P1 ___________ P2 ____________ 3 P1 _________________ P2 ___________ P1 ___________ P2 ____________
VCALIB150 = _______________
Computed Results from Above Data: VCELL150 = _______________ VEXP150 = _______________
S/N:____________________ Date Calibrated:____________________ Technician:__________________________________________________
APPENDIX C
SAMPLE RESULTS COMPUTATION
PROGRAM
SAMPLE RESULTS COMPUTATION PROGRAM
APPENDIX D
DERIVATION OF CALIBRATION
EQUATIONS
DERIVATION OF CALIBRATION EQUATIONS
Prior to running samples on the MultiVolume Pycnometer 1305, the volume of the sample cell and the expansion volume must be known. The derivation that fol-lows permits these internal volumes to be measured with respect to a removable, accurately known standard volume. A simplified diagram of the instrument is shown below.
Assume that, VCALIB is removed, VCELL is charged to an elevated gauge pressure
P1 and VEXP is at zero gauge (ambient) pressure but sealed and that the valve is
closed. Upon opening the valve, the condition established is
P1VCELL = P2(VCELL + VEXP) (1)
where P2 is the resulting intermediate pressure. The use of gauge pressures is
per-missible because it is equivalent to having subtracted a constant from both sides of the equation.
Placement of VCALIB into VCELL and repetition of the charging and expansion
yields
P1*(VCELL - VCALIB) = P2*(VCELL - VCALIB + VEXP) (2)
where P1* and P2* are the before and after expansion pressures with VCALIB in
place.
VCALIB, P1, P2, P1*, and P2* are assumed to be known or measurable. VCELL and
VEXP are to be found. Solving equation (1 for VEXP yields
VEXP = VCELL
P1− P2
P2
(3)
Substitution of equation (3) into equation (2) yields
P1∗(VCELL−VCALIB) = P2∗(VCELL− VCALIB)+ P2∗VCELL P1− P2 P2 (4)
Gathering terms and solving for VCELL further yields
VCELL = VCALIB(P1∗−P2∗) (P1∗−P2∗) − P2∗ P2 (P1− P2) (5)
Substitution of experimental and known values into equation (5) yields VCELL
which when used in equation (3) yields VEXP, the desired result.
Appendix D Model 1305 MultiVolume Pycnometer
INDEX
!
>35/<35 valve, 3-2 >5/<5 valve, 3-2A
Accessories, ordering, 5-1 Analysis performing, 3-12 theory, A-1 Analyzer calibrating, 3-16, 3-17, 3-18 controls and components, 3-1 description, 1-3environment, 1-7, 2-2
Precautions and intended use, 1-5 schematic, 1-4
selecting voltage, 2-2 specifications, 1-6 startup procedure, 3-8
turning off/shutting down, 3-19 unpacking and inspecting, 2-1
C
Calibration
See also Analyzer calculations, D-1 verifying, 3-15 volume, 3-5
Controls and components, 3-1 Conventions, manual, 1-2
D
Density, calculating, 3-14E
Equipment See AnalyzerF
FILL RATe valve, 3-3 FILL valve, 3-2 Filter, 3-6 Forms, A-3
G
Gas regulator, 2-6regulator, attaching to analyzer, 2-6 requirements, 1-7
Gas inlet pressure, 1-5 Gas inlet/outlet, 3-6
I
InsertSee Sample chamber
N
Notes, 1-2O
Ordering information, 5-1 Over-pressure relief valve, 3-6
P
Parts, ordering, 5-1 Precautions, 1-5 PREP/TEST valve, 3-3 Pressure display, 3-4 transducer, 3-5 unstable, 4-1 Pressure indicator fails to illuminate, 4-4 Purge procedure, 3-12Model 1305 MultiVolume Pycnometer Index