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4700
User Manual
36 pgs5.83 Mb2
Table of contents
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Parr Instrument 4700 User Manual

4.3 (3)
239M
4600 & 4700
General Purpose Pressure Vessels
Operating Instruction Manual
Table of Contents
PREFACE 3
CLOSURES 6
PARR PRESSURE VESSEL SEALS 7
Vessels with a Flat PTFE Gasket 7
Vessels with an O-ring seal 8
Vessels with a Flexible Graphite Gasket 8
Vessels with a Metal Gasket 8
HEAD ASSEMBLY GUIDE 12
MATERIAL DESIGNATIONS 12
Material Designations for Alloys other than T316SS 12
Gasket Material Designations 12
SERIES 4700 WORKING LIMITS AND PARTS LISTS 13
Series 4703-4714 13
Series 4740 14
Series 4750 15
Series 4760-4777 16
Series 4760Q-4777Q 18
Series 4790 20
SERIES 4600 WORKING LIMITS AND PARTS LISTS 22
Series 4600-4620 22
Series 4600Q-4620Q 23
Series 4605-4626 24
Series 4650 25
Series 4660 26
Series 4660Q 27
Series 4670-4674 28
Series 4676-4677 29
Series 4678-4679 30
Series 4680 31
4316 & 4317 GAGE BLOCK ASSEMBLIES 32
Gage Block Parts List 32
Gage Block Assembly Drawing 34
OTHER VESSEL HEAD FITTINGS 9
Tapered Pipe Threads 10
MAINTENANCE 10
General Maintenance Notes 10
Periodic Pressure Tests 11
2
Parr Instrument Company
Customer Service
Questions concerning the installation or operation of this instrument can be answered by the Parr Customer Service Department:
1-309-762-7716 • 1-800-872-7720
Fax: 1-309-762-9453
E-mail: parr@parrinst.com
http://www.parrinst.com
General Purpose Pressure Vessels

PREFACE

Scope

These instructions cover the basic operating steps to be followed when using a variety of pressure ves­sels manufactured by the Parr Instrument Company. They include temperature and pressure ratings for Series 4600 and 4700 General Purpose Pressure Ves­sels, also instructions for the gage block assemblies commonly used with these vessels. This material is intended to be used in conjunction with several related instruction sheets listed on page 2 covering safety precautions and other information applicable to Parr pressure equipment. The user should study all of these instructions carefully before starting to use any Parr pressure vessels in order to obtain a complete understanding of the capabilities and limitations of these vessels, and to be well aware of the precautions to be observed in their operation.

Related Instructions

The following Parr publications are also included to further your understanding of this instrument and its component parts:

Intended Usage

This system has been designed for use as a high pressure reactor system. It has been designed, built, and tested to strict physical and electrical standards. However, it is the user’s responsibility to install and operate it in conformance with local pressure and electrical codes.
If this equipment is used in a manner beyond its intended usage, the protection provided by the equipment may be impaired.

Safety Information

To avoid electrical shock, always:
1. Use a properly grounded electrical outlet of correct voltage and current handling capability.
2. Ensure that the equipment is connected to electrical service according to local national electrical codes. Failure to properly connect may create a fire or shock hazard.
3. For continued protection against possible hazard, replace fuses with same type and rating of fuse.
No. Description
201M Limited Warranty
230M Safety Precautions to be observed when
operating Pressure Reaction Equipment
231M Operating Instructions for Parr Safety
Rupture Discs
285M Sealing Instructions for Flexible
Graphite Gaskets
323M Operating Instructions for Pressure
Relief Valves
551M Operating Instructions for 4838
Temperature Controllers
FX004 Health & Safety Assurance Certification
4. Disconnect from the power supply before maintenance or servicing.
To avoid personal injury:
1. Do not use in the presence of flammable or combustible materials; fire or explosion may result. This device contains components which may ignite such material.
2. Refer servicing to qualified personnel.
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General Purpose Pressure Vessels

Explanation of Symbols

II On position, full power heater switch
I On position, half power heater switch
O Off Position
~ Alternating Current (AC)
This CAUTION symbol may be present on the Product Instrumentation and literature. If present on the product, the user must consult the appropriate part of the accompanying product literature for more information.
This CAUTION symbol indicates that the surface may be hot.
Protective Earth (PE) terminal. Provided for connection of the Protective Earth (green or green/yellow) supply system conductor.

Environmental Conditions

This instrument is intended to be used indoors.
Caution! Do not use in hazardous atmospheres.
Operating: 15 ºC to 40 ºC; maximum relative humid­ity of 80% non-condensing. Installation Category II (over voltage) in accordance with IEC 664. Pollution degree 2 in accordance with IEC 664.
Altitude Limit: 0 to 6000 feet above sea level. Storage: -25 °C to 65 °C; 10% to 85% relative humidity.

Unpack Carefully

Unpack the equipment carefully and check all the parts against the packing list. If shipping damage is discovered, report it immediately to the deliver­ing carriers. The vessel, motor, heater, and tem­perature controller may be packed separately for convenience in shipping, but these parts are easily reassembled. Examine the components closely for any loose parts or shipping damage and be sure to check all layers of packing materials thoroughly so as not to overlook any parts which might otherwise be discarded.

Provisions for Lifting and Carrying

The Series 4600 and 4700 General Purpose Vessels and their components are very heavy. Before moving ensure all cables are disconnected. Use proper and safe lifting techniques when installing or moving the Series 4600 and 4700 General Purpose Vessels and/ or its components.

Cleaning and Maintenance

Periodic cleaning may be performed on the exterior surfaces of the instrument with a lightly dampened cloth containing mild soap solution. All power should be disconnected when cleaning the instrument.
There are no user serviceable parts inside the prod­uct other than what is specifically called out and discussed in this manual. Advanced troubleshooting instructions beyond the scope of this manual can be obtained by calling Parr Instrument Company in order to determine which part(s) may be replaced or serviced.
Ensure that any hot surfaces have had adequate time to cool before cleaning or maintaining the reactor and/or its components.
4
Parr Instrument Company
General Purpose Pressure Vessels

User’s Responsibility

All Parr Reactors and pressure vessels are designed and manufactured with great care to assure safe operation when used within their prescribed tem­perature and pressure limits. But . . . the basic responsibility for safety when using this equipment rests entirely with the user; who must:
1. Select a reactor or pressure vessel which has the
capability, pressure rating, corrosion resistance and design features that are suitable for its in­tended use. Parr engineers will be glad to dis­cuss available equipment and material options with prospective users, but the final responsi­bility for selecting a reactor or pressure vessel that will perform to the user’s satisfaction in any particular reaction or test must rest with the user – not with Parr.
In exercising the responsibility for the selection of pressure equipment, the prospective user is often faced with a choice between over- or under-designed equipment. The hazards intro­duced by under-designed pressure vessels are readily apparent, but the penalties that must be paid for over-designed apparatus are often overlooked.
Recognizing these criteria, Parr reactors and pressure vessels are offered in several different styles, each designed for convenient use in daily operation within certain temperature and pres­sure limits, using gaskets, closures and other elements carefully selected for safe operation within the limits specified for that design. But in order to preserve the validity of these designs, all temperature and pressure limits must be observed, and no attempt should be made to increase these limits by making alterations or by substituting components which are not recom­mended by Parr Instrument Company.
2. Install and operate the equipment within a
suitable barricade, if required, with appropriate safety accessories and in full compliance with local safety codes and rules.
All standard Parr pressure vessels are provided with either a suitable relief device or a means to attach one (typically in the form of a plugged opening). When a pressure vessel is delivered without a pressure venting device, it is the cus­tomer’s responsibility to provide pressure relief in order to protect the operator and the equip­ment from destructive high pressures. If you
need more information or need help in selecting a proper relief device, please contact Parr Instru­ment Company.
3. Establish training procedures to ensure that any person handling the equipment knows how to use it properly.
4. Maintain the equipment in good condition and establish procedures for periodic testing to be sure the vessel remains structurally sound.

Pressure and Temperature Limits

The working pressure and temperature at which any reactor or pressure vessel can be used will depend upon the design of the vessel and the materials used in its construction. Since all materials lose strength at elevated temperatures, any pressure rating must be stated in terms of the temperature at which it applies. The standard material of construc­tion for Parr Instrument Company is Type 316 Stain­less Steel.
Limits for vessels made of other materials and for other operating temperatures can be obtained from Parr Customer Service. No attempt should be made to increase these limits by making alterations or by substituting components that are not recommended by the Parr Instrument Company. It must also be understood that lower pressure and temperature limits may be required for modified reactors and for vessels made of special alloys.
Limits for vessels will be determined by the physi­cal characteristics of the vessel material and will be prescribed on an individual basis.
The maximum working pressure and temperature for any vessel is governed by the design of the vessel and the strength of the material from which it is constructed. There is also a close relationship between working pressure and temperature since the strength of any material will normally fall off as the temperature is increased. Temperature and pressure limits are also affected by the physical properties and temperature limits of the gaskets and seals used in the vessel, and by any valves, gages or other fittings attached to the vessel. Obviously, the safe operating pressure of any system can be no higher than that of its lowest rated component.
All Parr reactors show the maximum safe operating pressure and temperature imprinted on the cylinder.
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General Purpose Pressure Vessels

CLOSURES

Split Ring Closures

Most Parr pressure ves­sels are equipped with a unique split ring cover clamp in which the head of the vessel is clamped to the cylinder by a hardened steel ring which has been split into two sections. These sections slide into place from the sides without interfering with any fittings attached to the head.
The closing force is devel­oped by simply tightening a set of compression bolts in the ring sections with a hand wrench. As a further convenience, larger Parr vessels in one and two gallon sizes, and certain high temperature and high pressure vessels, are equipped with split ring closures which do not
4751 125 mL Vessel with
Split Ring Closure and
4316 Gage Block Assembly
simply sliding the split ring section into place from the sides and tightening the compression bolts while the cylinder remains in place in its heater or other fixed support.

Split Ring Closure Operations

All vessels with split ring closures, except the larger Series 4660, 4670 and 4680 sizes, must be removed from the heater and set on a bench or table top before attempting to remove the split rings and head.
1. To Open the Vessel: open the gas release valve
to discharge any internal pressure; then loosen the compression bolts in the split ring sections. Loosen the cone pointed screw in the outer band and lower the band to rest on the table. The ring sections can now be removed, and the head with all attached fittings is free to be lifted from the cylinder.
require an outer retaining ring or drop band. This allows the vessel to be opened and closed by
2. Before Closing the Vessel: examine the head seal carefully to be sure that it is in good condition. The seal should not have any nicks or be hard­ened, discolored, or deformed. Examine the mating surfaces on the cylinder and head to be sure they are clean and free from burrs; then set the head on the cylinder.
3. To Close the Vessel: put the two split ring halves around the head and cylinder flanges, fasten the latches or tighten the bolts as assembled before.
4. Routinely inspect the bolts on split ring clo­sures for lubrication and cleanliness. These screws should not be allowed to dry because the threads will seize. Regularly apply Parr High Temperature Anti-Seize Lubricant before this happens.

Screw Cap Closures

On the smallest Parr vessels a threaded sleeve and screw cap are used to clamp the head to a cylinder. This is a union type cou­pling in which proper alignment between the head and cylinder is always assured since neither of these parts rotates when the screw cap is tightened. The flat gasket is held in a recess in the head. The seal is made as the lip of the cylinder is compressed against the gasket through tight­ening the screw cap and sleeve. All components must be kept clean. The gasket must be re­placed whenever it becomes worn
4703 22 mL Screw
Cap Vessel
or damaged. Any nicks in gasket recess area or to the sealing face of the cylinder must be avoided.

Operating 4700 Screw Cap Vessels

To close the Series 4700 Screw Cap Vessels: raise the sleeve against the top rim of the cylinder; set the head on the cylinder and attach the screw cap. Turn the screw cap down until it is finger tight; then set the vessel in a Parr A22AC3 bench socket and tighten the cap firmly with a 21AC4 box wrench.
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Parr Instrument Company
General Purpose Pressure Vessels

PARR PRESSURE VESSEL SEALS

Several different head sealing arrangements are used in Parr Pressure Vessels, each selected for easy access to the interior of the vessel as well as for safe operation within the pressure and temperature limits for which the vessel is designed. Both flat compression type gaskets and O-rings are used in these designs.
The various gasket materials used in Parr pressure vessels are listed in Table I. Since several of these materials are produced by different suppliers under different trade names, the ASTM generic designa­tion is used in these instructions to identify the type of sealing material (or materials) recommended for each Parr vessel.

Flat Gasket or Self Sealing O-ring Closure

The flat gasket is held in a recess in the vessel head and a machine pilot on the cylinder closes the recess to completely contain the gasket. The split ring clo­sure used with this gasket has cap screws which must be tightened to develop the loading on the gasket.
The self sealing design features an O-ring retained in a groove on the vessel head. This design is self sealing and the split ring used with this sealing system does not require nor have the cap screws used with the flat gasket.
The flat PTFE gasket can be used to operating tem­peratures as high as 350 °C. The flat flexible graphite (FG) gasket can be used to operating temperatures as high as 600 °C.
O-rings are available in several different materials for use within the temperature limit listed in the following table.
Pressure and Temperature Limits
O-Ring Material Maximum Temperature
NBR 150 °C FKM 225 °C
FFKM 300 °C
PTFE 350 °C

Gaskets for Operating Temperature above 350 °C

Parr uses a flexible form of graphite which has proven to be an excellent high temperature sealing material. It has almost unlimited temperature range, retaining its structure at temperatures well above the maximum at which a metal gasket can operate, and offering broad corrosion resistance as well.
Metal Gaskets can be furnished if required for special applications. These are usually made of stainless steel machined to a unique diamond shape with edges which fit into supporting grooves in the head and cylinder of the vessel. This type of gasket re­quires careful maintenance and a uniform loading ap­plied by tightening a ring of compression bolts with a torque wrench. For easier handling, Parr has replaced its diamond shaped metal gaskets with flat, flexible graphite gaskets (FG) described above. But it will continue to furnish metal gaskets in custom vessels for applications in which a metal gasket appears to offer the best solution to a difficult sealing problem.

Sealing the Vessel

The maximum temperature of the vessels equipped with O-ring seals depends upon the material used for the O-ring. The most common material is a fluo­roelastomer (FKM) which has a 225 °C maximum operating temperature limit.

Seals for Operating Temperatures up to 350 °C

Parr uses both flat contained gaskets and O-rings made of different materials, each with a different maximum working temperature. Flat gaskets made of PTFE fluoropolymer resins are the recommended choice for many applications since PTFE materi­als are inert to most chemicals. PTFE gaskets will provide good seals under repeated opening and closing of the vessel if the gasket temperature does not exceed 350 °C.
Vessels with split ring closures are sealed by tight­ening the compression bolts in the split ring sec­tions with a wrench furnished with the apparatus. To ensure uniform loading, turn down each bolt finger tight, then tighten to the limit described below for the type of gasket being used. Do not over-tighten the compression bolts as this can generate exces­sive strain on the closure.

Vessels with a Flat PTFE Gasket

Tighten the compression bolts using a criss-cross pattern, applying a firm but hard pull to each screw. Use a torque wrench to apply 25 ft-lbs to each compression bolt. Let the vessel stand for about five minutes after the initial tightening, then tighten again to 25-ft lbs. This will compensate for any tendency of the PTFE gasket to flow under the loading pressure.
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General Purpose Pressure Vessels

Vessels with an O-ring seal

The self-sealing design features an O-ring retained in a groove on the vessel head. This design is self sealing and the split ring does not require or have the compression bolts used with the flat gasket.

Vessels with a Flexible Graphite Gasket

The closure bolts may be tightened using either an open-end wrench for smaller vessels where the bolt torque requirement is less or with a torque wrench where additional loading is required for the higher operating pressures.
Some of the gasket numbers shown in the attached table are furnished with vessels that have different maximum working pressures. We have shown the maximum torque value to correlate to the maximum working pressure of the vessel.
It is important to make sure that the bolts are periodically lubricated with a high-temp anti-seize compound to insure that they move freely so that the desired torque value is obtained in the tighten­ing procedure.
It is also important to insure that there is uniform loading on all of the bolts. Make sure that the head sits levelly on the cylinder. Install the split ring and tighten all bolts finger tight.
Pick a starting position and tighten the bolt to 5 or 10 ft-lbs depending on the maximum amount of torque to be applied. For those vessels with a maximum torque requirement of 15 ft-lbs, a 5 ft-lb increment is appropriate. For vessels with a maximum of 135 ft-lbs, 20 ft-lb increments may be used.
Bolt tightening should continue in a criss-cross pattern from the initial bolt with the second bolt 180 degrees from the first and continuing until all bolts are tightened. Repeat this procedure increasing the torque to the required level as shown in the table below.
Torque Required For Sealing Vessels
with Flexible Graphite Gaskets
Vessel Series
No.
4600 1900 315HC4KL 35 4790 3000 to 5000 429HC2KL 15 4760 3000 457HC3KL 35 4650 5000 to 6000 457HC3KL 40 4660 190 0 655HC3KL 35 4680 5000 1808HCKL 40 4670 3000 1812HCKL 35 4740 8500 1829HCKL 15 4676 190 0 1559HC2KL 135
Note: It may be possible to extend the life of the Flexible Graphite gasket by coating both sealing surfaces of the head and cylinder as well as the gasket itself with a silicone base lubricant. Additionally, it helps to rough up the cylinder lip with 120 grit sandpaper to insure that the gasket remains in the head recess and does not stick to the cylinder.

Vessels with a Metal Gasket

Pressure vessels with a metal gasket require a uniform loading on the gasket carefully applied by tightening a ring of compression bolts with a torque wrench. The amount of torque to be applied will vary with different vessels and with the intended maximum working pressure. Specific sealing instructions will be provided for any Parr pressure vessels with a metal gasket furnished on special order.
Maximum
Working
Pressure, PSI
Graphite
Gasket
No.
Torque
Required
ft-lb
8
Parr Instrument Company
General Purpose Pressure Vessels
G
y

Sealing 4740 High Pressure Vessels

Closing operations for the 1.0 inch I.D., Series 4740 high pressure vessels are similar to those described for larger vessels with flexible graphite gaskets, except on the 4740 Series the compression screws are carried in a screw cap instead of in a split ring. When closing a 4740, clamp the cylinder in a vise; check the graphite gasket to be sure that it fits prop­erly in the head groove; set the head on the cylinder and add the compression ring. Check the screw cap to be sure that the six screws have been turned back so that they do not project through the cap, and then screw the cap onto the cylinder. Turn it down as far as it will go, then back it off about 1/8 turn. Now, tighten the screws with a torque wrench with an initial 10 ft-lbs using the criss-cross pattern described for larger vessels. After all have been tightened to 10 ft-lbs, repeat the procedure, increasing the torque until all have been tightened to the recommended 15 ft-lb limit.

OTHER VESSEL HEAD FITTINGS

Gage Block Assemblies

age
mbl
age
The valve in this assembly controls the flow of gas into the vessel and the gage shows the internal pressure when the valve is closed. Two styles are offered: The 4316 gage block assembly has a 3-1/2” dia. pressure gage and a Type A socket connector. This unit is normally used on smaller vessels where space is limited.
The 4317 gage block assembly has a 4-1/2” dia. gage and a Type B connector. It is typically furnished on vessels one liter and larger.

Pressure Gages

Pressure gages display in both psi and bar in vari­ous ranges for use on Parr gage block assemblies. The available ranges are shown in the gage block parts list. All of these gages have stainless steel cases with T316SS Bourdon tubes and ¼” NPT male connections. Gages constructed of Alloy 400 are available on special order.

Safety Rupture Discs

Detailed instructions for the safety rupture disc installed in Parr gage blocks and heads are provided in a separate Instruction Sheet No. 231M. The user should review these instructions carefully. Please note that the operating pressures in the vessel should not exceed 90% of the range of the pressure gage and rupture disc. Also note the warning that the discharge port from the rupture disc must always be directed away from all operating personnel. A compression fitting for use with 3/8” O.D. tubing is attached to the rupture disc body. It is recommend­ed that tubing be attached to this connector to carry any discharge to a fume hood or safe area in the event of an over-pressure. The free or discharge end of any attached tubing must be anchored securely.

Coned Pressure Fittings

The coned pressure fittings used to connect gage blocks, pressure hoses and other detachable parts
Parr gage block assemblies combine the function of an inlet valve, a pressure gage and a safety rupture disc in a compact assembly on a block which can be attached to the head of a pressure vessel with a single connecting tube. There is a threaded socket in the block for a gas connection with a pressure hose or tubing using a Type A coned pressure fitting. Coned pressure fittings are also used on the tube which connects the block to the pressure vessel.
to Parr pressure vessels are illustrated below. These fittings have a sleeve with a left-handed thread which screws onto the end of a thick-walled tube plus a compression nut to complete the assembly. When screwed into a matching socket, these parts form a rigid joint which will remain tight over a wide temperature and pressure range, yet the joint can be made and broken repeatedly without destroying the sealing faces. No gasket is required.
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General Purpose Pressure Vessels
TUBING
Coned Pressure Fittings
Type A B
NUT
BUSHING
D
E
Tube Size 1/4” 3/8”
Thread (D) 9/16-18 3/4-16
Bore (E) 3/32” 1/8”
Nut No. 35HC 326HC
Bushing No.
40HC 366HC
When using these coned connectors, screw the bushing onto the tube as far as it will go; then insert the end of the tube into the head or gage block and tighten the compression nut firmly while holding the block stationary with the gage facing in the desired direction. Note that this assembly behaves like a pipe union, allowing the connecting tube or hose to remain stationary while the joint is tightened.
Note: PTFE tape is not required on these connectors.

MAINTENANCE

General Maintenance Notes

1. Periodically inspect all electrical wiring and pres­sure connections for excessive corrosion. Sus­pect parts should be replaced by components only supplied by Parr Instrument Company.
2. Always use appropriate wrenches on all fittings and valves. Never use pliers or pipe wrenches.
3. Head and cylinder service fixtures are available for convenience and protection of components during maintenance of your reactor.
Note: For more information about available service fixtures, reference TechNote 307.
4. A light coating of thread lubricant, such as Parr High Temperature Anti-Seize Lubricant, (424HC2) should be applied to the straight threads of coned pressure connections as well as to the nose of the mating piece this will help to obtain a tight joint.

Tapered Pipe Threads

The pressure gage, needle valves and other fixed attachments on Parr vessel heads have tapered pipe threads which are not to be disturbed after they have been screwed into place. If it becomes neces­sary to remove any of these fittings, the pipe threads must be coated with PTFE tape, flexible graphite tape, or similar luting material on reassembly.
The ID of a pipe or pipe fitting can be enlarged to accommodate a tubing feed-thru. Note that, in some cases, this may cause a reduction of the pressure rating. The port below a female pipe connection can also be opened up to a larger size.
The maximum openings are shown in the table below.
Tapered Pipe Threads
A
Nominal Size
B
Pipe OD (A) 0.405” 0.540”
Maximum Feed-thru (B)
Maximum Exit
C
Port (C)
1/8” 1/4”
1/4” 3/8”
0.339” 0.458”
Note: PTFE tape should be used only on all tapered (NPT) threads not NPS straight threads.
5. NPT (National Pipe Taper) threads should not be disassembled any more than necessary. It will become increasingly difficult to maintain a tight seal with these tapered threads if the joint is made and broken repeatedly.
6. Do not use oil or anti-seize lubricant on threads or fittings if the vessel is to be used with oxygen.
7. If your vessel is equipped with a loose compres­sion ring be sure that it is in place on the head before attaching any head fittings. The compres­sion ring cannot be installed after fittings have been screwed into the head.
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Parr Instrument Company
General Purpose Pressure Vessels
8. Clean all threads and gas passages thoroughly and remove all tape fragments when overhaul­ing a vessel. An ultrasonic bath is excellent for cleaning metal parts, but do not place a thermo­couple probe, pressure gage, face seals or ball bearings in an ultrasonic bath. Periodic cleaning may be performed on the exterior surfaces of the reactor stand with a damp cloth. All power should be disconnected when cleaning.
9. Routinely inspect the bolts on split ring clo­sures for lubrication and cleanliness. These screws should not be allowed to dry because the threads will seize. Regularly apply Parr High Temperature Anti-Seize Lubricant before this happens. It is important to keep the bolts lubri­cated so they will not seize and also to achieve the intended torque value.
10. Routinely inspect screw cap threads for wear and cleanliness.
11. If servicing assistance is needed, contact Parr In­strument Company direct at the address shown on the back of these instructions.

Periodic Pressure Tests

Each cylinder used in a Parr pressure vessel is tested under hydrostatic pressure at room temperature to the higher of 1.43 times the rated working pressure or 1.30 times the rated working pressure corrected for room temperature before it is released from the factory. Micrometer caliper measurements are taken during this test to check the deflection of the walls under pressure. Excessive deflection or failure of the metal to resume its original dimensions after pressure is released indicates that a cylinder is po­tentially unsafe and it will be rejected. Similar tests should be made at regular intervals during the life of each cylinder, and particularly whenever the user suspects that the equipment has been over-stressed or damaged.
Some laboratories maintain hydraulic test facilities and make it a rule that all pressure vessels must be tested at regular intervals. Records are kept of deflections at specific test pressures so that any increase in deflection becomes a warning that the metal has lost strength. Any cylinder that fails to return to its original dimensions after application of the prescribed hydrostatic test should be discarded as unsafe for further use.
Users who do not have pressure test facilities can return any Parr pressure vessel to the factory for hy­drostatic testing and overhaul. This should be done whenever the metal shows excessive damage from corrosion or whenever an over-pressure or other unusual occurrence raises any safety questions.
To return a vessel for repair, contact Parr Instrument Company for a return authorization number (RMA).
Apparatus returned for testing and overhaul should be shipped prepaid to the following address:
Ship repair to:
Parr Instrument Company Attn: Service Department RMA # XXXXXX 211 53rd Street Moline, Illinois 61265 USA
An order or letter of instructions should be mailed to the same address, as no repair work will be started without specific instructions and a Health & Safety Assurance Certification form (FX004) signed by a responsible user.
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