phpk cryogenic equipment · 2004-11-05 · vacuum jacketed piping heat leak the following table...

PHPK TECHNOLOGIES INC. • 535 ENTERPRISE DRIVE, WESTERVILLE, OH 43081 • (614) 436-9114 FAX (614) 436-5816e-mail: [email protected] • web site: http://www.PHPK.com

6/97

© 1997

1 - 1

Vacuum jacketed transfer systems

PHPK provides vacuum jacketed transfer systems which are custom-engineered and designed tomeet customer-specific requirements.

All PHPK vacuum jacketed transfer piping is availablewith a variety of options dependent upon service, fluid,environment, documentation requirements, qualityissues, safety requirements, site and installation conditions, economic considerations, and other customer-specific requirements. Although all PHPK systems are engineered, designed, fabricated, and inspected to the ANSI/ASME B31.3 “Petroleum RefineryPiping Code” latest addenda, PHPK offers service andquality standards which reach far beyond code require-ments. Many of these, such as specialized cleaning andstate-of-the-art bake-out and evacuation equipment, areprovided as standard service with every system.

PHPK T E C H N O L O G I E S I N C O R P O R A T E D


© 1997

1 - 2

All PHPK vacuum jacketed piping is cleaned,fabricated, evacuated, tested, and sealed inour totally air-conditioned factory using acombination of the latest technology andforty-five years of experience and proventechniques. Static Vacuums, LaminarRadiation Shielding, a Chemical GetteringSystem, and a complete line of PHPK-fabricated components ensure easy installation and PHPK service from contractaward to system start-up.PHPK doesn’t stop there; our warranty and technical staff ensure support for thelife of the system.

PHPK provides all-stainless steel systems,rigid, flexible, and combinations. Toughrequirements and special needs are standardat PHPK. The PHPK Quality System has beenapproved by Hartford to be in accordance

with the ANSI/ASMEB31.3 Piping Code. PHPKvacuum jacketed piping has foreign registration, haspassed the U.S. Navy shockqualification standards forship-board piping, and isaccepted by major cryo-genic liquid suppliers, and government agencies.

1 - 3

© 1997


6/97

PHPK-engineered transfer systems utilize the latest computer software for engineering analysis,design, and fabrication. PHPK components used in the transfer systems are manufactured using thesame high-quality standards and are tested to meet the customer’s service requirements.

Standard System Engineering includes a review of the system for:

■ Dimensional configuration

■ Pressure drop

■ Heat leak

■ Supports and anchors

■ Thermal stress

■ Thermal flexibility

■ Shippability (field joint location)

■ Installation compatibility

■ Quality requirements

■ Economic design, including accessories such as valves, cryogenic couplings, etc.

■ Future add-ons or reconfiguration

■ After sale and installation engineering service

Standard System Manufacturing:

■ Material review and certification

■ Section VIII certified welders, procedures, and specifications

■ Fabricated and tested to ANSI/ASME B31.3 Piping Code

■ Vacuum tested to 1 x 10-9 scc/sec helium

■ State-of-the-art cleaning systems

■ State-of-the-art bake-out system


© 1997

1 - 4

Engineering Support

In addition to those items listed as standard for all PHPK-engineered systems, PHPK support staffis always available to answer the “what if” questions and has over 45 years of proven support tothe cryogenic industry. PHPK vacuum jacketed transfer systems are installed and in service inapplications ranging from U.S. automakers, Navy carriers, and air separation facilities, to shuttlelaunch test facilities and support systems. Each system is engineered, analyzed, and designed toprovide the ultimate transfer system to meet the specification, quality, and economic considerationspecified by the end user. Analysis programs include stress (thermal, support, seismic), pressuredrop, heat leak, component, and specialty requirements. Exotic materials, such as Hastelloy andNitronic 40 are every day requirements for PHPK custom-engineered systems.

Engineering Design

Each PHPK piping system is custom-designed and engineered to meet ASME Pressure PipingCodes and our customer’s specifications. Engineering design includes PHPK equipment andknow-how along with industry standards.

Standard PHPK design features include:■ Design, fabrication, and testing to the ANSI/

ASME B31.3 Chemical Plant and Petroleum Refinery Piping Code

■ Laminar Radiation Shielding (Superinsulation) consisting of alternate layers of aluminized mylar (aluminized both sides) or aluminum foil (if required by specification) and microfiberglass paper.

■ End closures to meet specification heat leak and connection requirements

■ Chemical gettering system using a captured getter design to preclude contamination of the vacuum annulus

■ Flexibility analysis to insure system reliability at cryogenic temperatures. This can range in scope from an engineering design review to a complete computer-generated report (dependent upon specification requirements).

1 - 5

© 1997


6/97

Fabrication, Testing, and Quality Assurance

PHPK transfer systems are fabricated using the latest state-of-the-art equipment and technology toensure the quality is built into PHPK vacuum jacketed transfer systems and not inspected in after thefact.

■ PHPK quality includes an independent survey of our facilities, fabricating, and quality procedures to insure they conform to the latest ANSI/ASME B31.3 Code and other applicable codes and standards.

■ PHPK requires all vacuum jacketed piping to be fabricatedfrom new materials with chemical and physical mill certifications.

■ During preparationfor fabrication, eachcut section of pipe ispre-cleaned using anenvironmentally- friendly, heated, filtered,pressure circulated solution which thoroughly cleans andremoves contaminationand hydrocarbon residue.

■ All piping is weldedusing new state-of-the-artHeli-arc (TIG) weldingmachines. All PHPK weldingis performed in accordancewith ASME Boiler and Pressure Vessel Code. Our on-staff welding engineer has developed and qualified procedures with a variety of materials and thicknesses,including Hastelloy and Titanium. All welding is quality tested, including as a standard, 5% random radiography to codestandards. Procedures are charpy impactqualified to -452oF.


© 1997

1 - 6

■ Each piping section is mass spectrometer leak tested with the equip-ment sensitivity set at 1 x 10-9 scc/sec ofhelium.

■ PHPK piping is proof pressure testedto meet the latest revisions of the ASMEpiping codes as a minimum.

■ Each PHPK-fabricated piping system is baked-out and evacuatedusing a PHPK-fabricated, state-of-the-art system which incorporates PLC-controlled temperature to each individual piping section during theduration of the process.

■ All piping is quality monitored tomeet code and cus-tomer specifications,and to ensure PHPKvacuum jacketedtransfer systemsarrive ready for service.


6/97

© 1997

1 - 7

Typical Vacuum Jacketed Transfer System

1. Liquid supply tank2. Relief valve3. Remote on/off valve 4. Bayonet connection5. Flexible hose for thermal

movement and field fit-up6. V.J. spool section7. Manual shut-off valve at

equipment location8. Capped bayonet for future system

expansion9. Liquid/Gas phase separator

10. Valve manifold for multiple-use points

Vacuum Jacketed Piping Heat Leak

The following table reflectstypical heat leak values forPHPK vacuum jacketed piping. These conservativevalues include componentssuch as elbows, tees, etc., andare good for estimating totalpiping system heat leak.Components such as valvesand bayonets should beadded to establish an overall budget heat leak performance.

RIGID

0.37 (0.11)

0.43 (0.13)

0.47 (0.14)

0.58 (0.17)

0.79 (0.23)

0.98 (0.29)

1.28 (0.38)

1.65 (0.48)

FLEX

0.97 (0.28)

1.21 (0.35)

1.43 (0.42)

1.74 (0.51)

2.37 (0.70)

2.95 (0.86)

3.85 (1.13)

4.97 (1.46)

RIGID

0.37 (0.11)

0.42 (0.12)

0.47 (0.14)

0.57 (0.17)

0.65 (0.19)

0.84 (0.25)

1.01 (0.30)

1.36 (0.40)

FLEX

0.96 (0.28)

1.19 (0.35)

1.41 (0.41)

1.71 (0.50)

1.95 (0.57)

2.52 (0.74)

3.03 (0.89)

4.10 (1.20)

RIGID

0.40 (0.12)

0.46 (0.13)

0.51 (0.15)

0.63 (0.18)

0.85 (0.25)

1.08 (0.32)

1.40 (0.41)

1.83 (0.54)

FLEX

1.05 (0.31)

1.29 (0.38)

1.54 (0.45)

1.89 (0.55)

2.56 (0.75)

3.24 (0.95)

4.22 (1.24)

5.50 (1.61)

HEAT LEAK in Btu/hr/ft and (Watts/ft)

LINE SIZE

3/4" OD x 1-1/4" NPS

3/4" NPS x 2" NPS

1" NPS x 2-1/2" NPS

1-1/2" NPS x 3" NPS

2" NPS x 4" NPS

3" NPS x 5" NPS

4" NPS x 6" NPS

6" NPS x 8" NPS

LN2 LO2 LH2


© 1997

1 - 8

Vacuum Jacketed Transfer System Design Guide

As an aid in developing your vacuum jacketed system, PHPK offers the following approach to designand specification.

■ During the planning stages of the system, allow adequate time to engineer, design, and fabricate a custom piping system. Vacuum jacketed piping should not be viewed as conventional plumbing. Contact PHPK to help establish schedules.

■ Establish the basic routing of the system, allowing clearances for installation, valves, and othersystems current and future.

■ Complete an isometric sketch or plan and elevation drawings to aid in determining exact components required. Be sure to note wall or roof penetrations and installation restrictions.On complex systems, include a P&ID.

■ Size the pipe and components using expected current and future flow rates. Initial installations should plan for potential future expansion.

■ Consider features such as:• larger mains and branches for high-usage areas,• smaller branches for lower-usage areas,• flexible sections for field adjustment, congested areas, alignment problems, special angles, and

disassembly,• vacuum jacketed in-line valves for system or function shut-down or flow control,• capped bayonet couplings for future expansion,• internal trapped drops for reduced heat leak and fast system response,• relief devices for trapped volumes.

■ Refer to PHPK Vacuum Installation Piping Specification for a procurement specification guideline.

■ Call PHPK for design assistance.


6/97

© 1997

1 - 9

PHPK is providing the following engineering data to aidin establishing system line size.This information is not providedto replace a complete system sizing review, but rather to size a system for initial design andpricing. Total pressure dropincludes losses through valves,fittings, and changes in elevation.Call PHPK for a copy of our vacuum jacketed piping pressure drop program.

PHPKTECHNOLOGIES

PHPKTECHNOLOGIES

PRESSURE DROP IN LIQUID NITROGEN FLUID FLOWTube/Schedule 5 Pipe - psi/100ft Flex Hose - psi/10ft

PRESSURE DROP IN LIQUID OXYGEN FLUID FLOWTube/Schedule 5 Pipe - psi/100ft Flex Hose - psi/10ft


© 1997

1 - 10

PHPKTECHNOLOGIES

PHPKTECHNOLOGIES

PRESSURE DROP IN LIQUID HYDROGEN FLUID FLOWTube/Schedule 5 Pipe - psi/100ft Flex Hose - psi/10ft

PRESSURE DROP IN LIQUID HELIUM FLUID FLOWTube/Schedule 5 Pipe - psi/100ft Flex Hose - psi/10ft


6/97

© 1997

1 - 11

PHPKTECHNOLOGIES

PHPKTECHNOLOGIES

PRESSURE DROP IN LIQUID ARGON FLUID FLOWTube/Schedule 5 Pipe - psi/100ft Flex Hose - psi/10ft

PRESSURE DROP IN LIQUEFIED NATURAL GAS FLOWTube/Schedule 5 Pipe - psi/100ft Flex Hose - psi/10ft


© 1997

1 - 12

PHPK also fabricates vacuum jacketed piping systems for liquid helium service, where heat leak andfinal system design are of prime importance to performance and economic operation. PHPK utilizesthe same attention to quality, design, and performance as with other vacuum jacketed systems, withspecial considerations for insulation, spacer supports (inner line to jacket), and component designsuch as extended-length valves and bayonets. With modifications to standard designs, PHPK helium systems provide an economic approach to low heat leak helium requirements without significant increases in system cost.

For ultimate performance with specialty helium systems, PHPK makes liquid nitrogen/cold heliumgas-shielded systems available. These systems are economically justified only where the transfer linesrequire many components, such as valves and bayonets, with ultra-low total heat leak requirements.The shielded piping provides a means of heat stationing components to reduce heat leak in additionto the increased thermal performance provided to the piping. These systems are very specialized andshould be considered only where the ultimate performance is required. PHPK engineering will aidyou in your design and specification requirements for helium systems, shielded and non-shielded.

The following engineering data is supplied to help in establishing helium transfer system requirements. Actual performance will depend upon final configuration and design.

* Jacket size will be larger for shielded systems.Larger line sizes are available for special applications.Refer to pressure drop curves for LHe to establish system line size.

HEAT LEAK (HELIUM VACUUM JACKETED PIPING)-UNSHIELDED or SHIELDED in Btu/hr/ft and (Watts/ft)

LINE SIZE

1/2" x 2" *NPS

3/4" NPS x 2" *NPS

1" NPS x 2-1/2" *NPS

1-1/2" NPS x 3" *NPS

2" NPS x 4" *NPS

UNSHIELDED

0.27 (0.08)

0.29 (0.09)

0.32 (0.09)

0.37 (0.11)

0.42 (0.12)

WITH LN2 OR GHE SHIELD

0.06 (0.02)

0.07 (0.02)

0.08 (0.02)

0.10 (0.03)

0.11 (0.03)

Vacuum Jacketed Transfer Systems forLiquid and Gaseous Helium


6/97

© 1997

1 -13

Specifications

Specifications for Vacuum Insulated Piping General Fabrication, Testing and Purchasing

1.0 SCOPEThe American National Standard Code for Pressure Piping, ANSI/ASME B31.3 Chemical Plantand Petroleum Piping’s latest edition, establishes the requirements for engineering, design, fabri-cation, and testing of piping used in liquid and gas cyrogenic service. PHPK TechnologiesIncorporated’s specification, number 01-50-1001, is established as a base line to meet or exceedthose requirements during the production of this class of piping with specific emphasis on areaswhich are not code-regulated, such as vacuum and thermal insulation, but are of prime impor-tance in the fabrication of a quality vacuum insulated, or double-wall containment piping system.

1.1 This specification describes the requirements for a vacuum insulated piping (VIP) system forthe transfer of ____________________. The attached system layout and details show the generalsystem configuration.

1.2 System line sizes are ____________________.

1.3 System design pressure is ___________________.

2.0 ENGINEERING DESIGNPHPK engineering/design staff will insure that the following areas meet code requirements, contract specifications, and sound engineering practices.

2.1 Components All components will be reviewed for conformance to the design parameters required byANSI/ASME B31.3 code, latest edition.

2.2 FlexibilityThe system will be analyzed to insure thermal flexibility. This includes analysis of individualspool sections as well as the total system, while considering allowable stress levels of materials of fabrication as well as consideration for site conditions, anchors, supports, and interface connections.

2.3 Component LocationAll components including valves, relief valves, cryogenic couplings, and seal-off valves will bereviewed for system location while considering supports, anchors, site, safety, accessibility, andinterference with existing equipment.



© 1997

1 -14

2.4 Non-Destructive Testing (NDT)All components and piping testing will meet code requirements as a minimum. When the code doesnot regulate testing, such as vacuum integrity, PHPK engineering/design staff will require NDT tomeet quality standards set down by this specification/customer specification and contract.

2.5 Safeguards (Appendix “G” ANSI/ASME B31.3)When required by the customer’s specifications, PHPK engineering/design will give appropriate consideration to safeguarding the system.

3.0 MATERIAL AND COMPONENT SELECTIONPHPK will use only code-qualified components and materials as defined in Chapter III and ChapterIV, Table 326.1 of the ANSI/ASME B31.3 and/or as listed in Appendix “A,” for use within the systemand component temperature limits. All PHPK material components will be of new, traceable origin.No used material or material of unknown origin will be permitted.

3.1 Inner (Process)Process pipe will be fabricated using Type 304/304L (dual graded), ASTM A-312 stainless steel pipe,welded or seamless. Tubing will be fabricated using Type 304/304L or (dual graded), ASTM A-269stainless steel tube welded or seamless.

3.2 Vacuum Jacket Piping used for the vacuum jacket will meet the same requirements as the inner pipe and will beschedule 5 or greater, the wall thickness will be in conformance to Section VIII, Division 1, of theBoiler and Pressure Vessel Code, paragraph UG-28.

Where heavier wall is required for pipe supports or anchors, PHPK engineering will review and reinforcements will be added to meet design conditions.

3.3 Fittings Inner-line fittings will be butt weld and will conform to ASTM A-403 WP-W or A-403 WP-S, grade 304/304L stainless steel. Flanges will conform to ASTM SA-182, grade 304/304L stainless steel.

No inner-line mitered elbows will be used. Where branch line (tee) miters are used, connections willbe designed and fabricated per ASTM B31.3 code requirements.

1 -15

© 1997


6/97

3.3.1 ValvesVacuum jacketed valves will be PHPK manufactured, which conform to the pressure rating, material,and other design features required to meet specified service. All cryogenic extended-stem globevalves will be PHPK model ________. Castings will be lost wax investment cast, ASTM-A-743, grade CF3 (304L) stainless steel, zyglo and radiograph inspected. Valve component materials of construction will be 304L or 300-series stainless steel. Bonnets will be bronze alloy. All butt weld connections will be “true butt weld” with no closed-end cavities (such as socket weld) which cannotbe easily cleaned for oxygen service. Seal disk material will be PCTFE M400H (Kel-F). Valve barreland bonnet bolts will be plated with a PHPK-specified, patented nickel/teflon plating which has beentested and approved for oxygen service. This plating, unlike chrome, does not chip or flake and provides a homogeneous surface to prevent galling. The valve design provides a close-tolerance fit(approximately 0.003”) between the barrel and the body extension tube, allowing operation in any orientation, even upside-down, while insuring bonnet (Viton O-ring) seals remain warm when thevalve is in cryogenic service. Valves will have self-locking seat seals which do not require staking or welding for assembly or maintenance.

3.4 Expansion JointsPiping spools will be designed and fabricated using single-ply external bellows to compensate forthermal cycling. Bellows material will be type 304, 316, or 321 stainless steel. End connections will be304/304L stainless steel. The bellows will meet the requirements of the EJMA, (Expansion JointManufacturers Association), and ASME B31.3 for 35 psig internal pressure/20 psig external and 0 psiainternal. Normal movement will not exceed 75% of the maximum rated movement for a design cyclelife of 5,000 complete cycles.

3.4.1 Flexible ComponentsFlexible hose may be used on the inner line and vacuum jacket to compensate for system movement.When used, protective braid will be installed on both the inner line and jacket and the design willmeet the manufacturer’s recommendations and EJMA design.

3.5 Vacuum ClosuresVacuum end closures may be required between the inner process line and the vacuum jacket.Engineering/design will consider system heat leak, thermal stress, shipping loads, and system performance requirements while evaluating the type of vacuum closure to be used.

3.5.1 Cryogenic Couplings (Bayonets)When bayonet connections are used they will be PHPK design. All male and female bayonets will beclose-tolerance fit (0.003” to 0.004”) between matching parts and will utilize a warm gas vapor O-ringseal. Coupling flange will be designed to accept V-band or flanged connection, as specified. Bayonetswill be mass spectrometer leak-tight and will have no unsealed cavities (such as socket welds) whichcan trap contaminants and cannot be totally cleaned for oxygen service. All male parts are to be plat-ed with a licensed, patented, oxygen-compatible, PHPK-specified, anti-galling coating.


© 1997

1 -16

3.6 Inner Pipe Supports (Spacers)The inner (process) pipe will be centered within the vacuum jacket by a support system designed totransfer the loads between the two (2) pipes during thermal cycles with the inner line filled withprocess fluid, as well as during shipment. In addition to thermal and shipping loads, the spacerconfiguration will be designed to minimize heat leak into process pipe.

3.6.1 Spacer design will withstand the following loading during shipment and after installation:

• Three (3) “g” load applied vertically downward• Three (3) “g” load applied vertically upward• Two (2) “g” load applied horizontally (longitudinally or laterally) combined with a one

(1) “g” load vertically downward• Meet the uniform building code for zone 4 seismic requirements with the inner line

filled with process fluid

3.7 Laminar Radiation Shielding (Superinsulation)The inner (process) pipe will be wrapped with a minimum of sixteen (16) alternative layers of aluminized mylar, (aluminized both sides, 32 reflective layers), and glass fiber insulation.

3.8 Chemical Gettering System Each spool assembly will have a chemical gettering system installed during fabrication. The system will consist of a calcium zeolite desiccant, (Linde Type 5A molecular sieve), and a hydrogenconverter such as palladium oxide. The quantity of each material in the gettering system will bedetermined by PHPK based upon the diameter and length of the spool.

In oxygen service, special provisions will be made to isolate the hydrogen converter from contacting other inner line materials.

3.9 Evacuation Port (Vacuum Seal-off)Each pipe spool assembly will be fabricated with a PHPK seal-off and relief valve (Model VR-46),bellows-sealed isolation valve, and a thermocouple vacuum gauge tube. Each PHPK seal-off valve is all-stainless steel construction, equipped with a double O-ring seal to prevent vacuum lossfrom vibration or shock, and a threaded spring O-ring sealed relief cap to prevent moisture andcontamination from entering the valve internals. Stainless-to-stainless threads will be plated andprotected from galling and corrosion with a PHPK-specified, patented nickel/teflon plating. Theseal-off valve assembly provides a combination pump-out opening, seal-off, and relief device. Theseal-off port assembly will be positioned on each spool in an approved location considering safety,accessibility to pump-down devices, and non-interference with neighboring equipment. Each thermocouple gauge tube assembly will be covered to prevent damage while in service.

1 -17

© 1997


6/97

3.9.1 Vacuum Gauge Tubes/Isolation ValveEach spool will be equipped with a thermocouple vacuum gauge tube to monitor the vacuum levelwithout breaking into the vacuum annulus. A bellows seal isolation valve will be placed between thevacuum annulus and the thermocouple gauge tube to isolate the tube for maintenance.

4.0 FABRICATIONPiping will be fabricated in a clean, well lighted air-conditioned shop, in such a manner as to preventundetermined stresses due to springing or forcing. Pipe ends will be cleaned and properly preparedto meet the code requirements for connection.

4.1 WeldingAll welding will be performed by welders who have been qualified to procedures and positions asrequired by ANSI/ASME Section IX, Article II, of the Boiler and Pressure Vessel Code for the material,temperature, and application intended. PHPK shop welding standards will meet the requirements ofANSI/ASME B31.3 Piping Code, Chapter V for full-penetration welds.

4.2 Welding EquipmentWelding will be performed using GTAW, GMAW, or orbital welding. The shielding gas may be argon,helium, or any procedure-approved mixture. Filler metal will comply with the procedures.

4.3 CleanlinessWork areas will be maintained in a clean orderly manner. Piping and components will be cleanedwith an environmentally-approved cleaning solvent inside and out prior to welding and after all cutting, grinding, or filing. All burrs, grease, oil, and metal residue will be removed prior to welding.The outside of the inner line will be cleaned prior to the installation of laminar radiation shielding.The inside of the vacuum jacket will be cleaned prior to installation.

Prior to final assembly and testing, the annular space of all vacuum jacketed piping will be thoroughlycleaned to remove contamination and hydrocarbon residue. This cleaning will be performed on allpiece-parts using PHPK-designed and fabricated system which pressure circulates, filters, and heats acleaning solution authorized by the USDA for use in federally-inspected meat and poultry plants andis environmentally safe. In addition, each piece is individually inspected prior to rinsing in a pressurecirculating rinse tank. All parts are completely air-dried prior to starting final assembly.

4.3.1 All surfaces to be cleaned will be completely wetted by means of immersion, circulation, flushing, spraying, or swabbing and dried with dry GN2 or dry, oil-free air.

4.3.2 Cleaned surfaces will be visually inspected for contamination, scale, or rust. Discoloration dueto welding will be acceptable. Any visual sign of contamination will be cause for recleaning the part.

4.3.3 White cloth, ultra violet, and special cleaning procedures will be dictated by the customer contract and specification requirements and will be addressed in separate specifications. Ultra violetlight examination for oxygen service will be addressed in Paragraph 7.1.


© 1997

1 -18

5.0 INSPECTION AND TESTAll inspection and testing will be directed by the Quality Assurance Manager and will meet therequirements of the PHPK Quality Assurance Manual and contract-related specifications. QualityAssurance is a function and requirement of each employee of PHPK. Final review of materials certifi-cation, welders qualification, record and test examination, and maintenance of records falls under the direction of the Quality Assurance Manager.

5.1 Required ExaminationExaminations required by the ANSI/ASME B31.3 Piping Code are:

• Visual Examination• Random Radiography• Component and material certification records

5.1.1 RadiographyFive (5) percent of all inner line butt welds will be random radiographed. Radiographs will be readand reader sheets will be prepared in accordance with the code by certified technicians.

5.1.2 Pressure TestingAll inner lines will be either pneumatically (not less than 125% of design pressure) or hydrostatically(not less than 150% of design pressure) pressure tested. Test pressure, medium, and time durationwill be directed by engineering/design and customer requirements.

Pneumatic testing is preferred because of reduced chance of inner line contamination, and when per-formed with a combination of nitrogen and helium gas, while mass spectrometer leak testing, thismethod provides more accurate leak detection.

5.2 Supplementary ExaminationSupplementary examination, beyond code requirements, will be detailed in separate specificationsand performed as directed by engineering/design. Specifications will include type of inspection/tests, procedure or method, standard, and acceptance criteria.

5.3 DimensionalUpon completion of fabrication, each spool assembly will be dimensionally inspected to verify thatdimensions meet engineering design. At the same time, each assembly will be visually inspected forworkmanship, material conditions, and completeness.

5.4 Combination Pressure/Mass Spectrometer Leak Test

5.4.1 With the spool seal-off valve connected to a Mass Spectrometer Leak Detector, with the sensitivity calibrated to 1 x 10-9 scc/sec, evacuate the annular vacuum space.


6/97

© 1997

1 -19

5.4.2 Blank off the inner line for pneumatic pressure test. The inner line will be pressurized with amixture of 90% dry nitrogen gas and 10% helium gas. Proof pressure will be reached in 25% stepswith each step pressure-held for two (2) minutes and the vacuum gauge monitored for increased pressure. The final proof pressure will be held for ten (10) minutes and the vacuum level monitored.Any change in pressure indicates a leak.

5.4.3 Upon completion of the pressure test, the pressure will be reduced to maximum design working pressure and the vacuum space (inner line welds) will be tested using the mass spectrometer.At the same time, the jacket welds will be sprayed or bagged with helium gas. Inner line welds notenclosed by the vacuum jacket will be soap bubble tested for leaks.

A no-leak indication by the mass spectrometer at 1 x 10-9 constitutes a successful test.

5.4.4 Upon completion of the pressure/leak test, the vacuum annulus will be brought back toatmospheric pressure by slowly backfilling with dry nitrogen gas. Likewise, the inner line pressurewill be released slowly.

6.0 EVACUATIONUpon the successful completion of the pressure and mass spectrometer leak test, each spool willundergo bake-out and evacuation.

6.1 Each line will be heated to between 212o and 250o F by forcing filtered and heated air through the inner line while the vacuum jacket is covered with insulating blankets. The inlet and exit temperature of the bake-out will be monitored and recorded. Each individual line temperaturewill be monitored to ensure proper exit temperature of the individual spool section.

6.2 Upon reaching the prescribed temperature (generally one (1) day), evacuation of the annularspace is started using a mechanical fore pump connected to the system through a diffusion pump and LN2 cold trap to prevent oil from back-streaming. Heating and pumping are continued until thespool vacuum is at approximately zero (0) microns. The time period is determined by the piping size (volume of the annular space) and the history of time/pressure reduction in reaching the zero-micronlevel. Total time for bake and evacuation is approximately five (5) to seven (7) days.

6.3 Vacuum Retention TestThe vacuum retention test will start after the vacuum seal-off valve has been closed and the spool has returned to ambient temperature. The pressure of each spool will be measured and recordedevery 24 hours using the thermocouple gauge tube. Each vacuum reading will be recorded with date, time, and ambient temperature. The minimum test period will be seven (7) days, unless otherwise authorized by the customer/PHPK engineering.


© 1997

1 -20

6.4 Test AcceptanceThe vacuum retention data is to be interpreted as follows:

6.4.1 If daily readings remain unchanged, other than effects of temperature variations, the spool isacceptable.

6.4.2 If daily readings increase less than two (2) microns per day for the first part of the test, followed by a period of no change, the spool is considered acceptable as long as the final maximum stabilized reading is below 30 microns.

6.4.3 A continuous pressure increase throughout the retention period indicates a leak. The spoolwill then undergo additional mass spectrometer leak testing until the cause can be found and corrected. The spool will then be baked out and re-evacuated, as required, and subjected to an additional retention test.

6.4.4 Normal retention test readings are 15 microns or less after seven (7) days with the last four (4)to five (5) readings stable. Some fluctuations may appear in the last readings attributed to ambienttemperature changes or simple out-gassing. Any spool reading over 15 microns, but not over 30microns with the last readings unstable, may be recycled through the baking/retention sequence orcold-shocked for one (1) hour using LN2 while monitoring the vacuum level.

The cold-shocked spool can be considered acceptable if the vacuum level is “off scale” (less than 1 x 10 -3 torr) during the one (1) hour test.

7.0 FINAL CLEANINGAll process surfaces will be final cleaned as required, after final welding, machining, threading, pressure testing, and final evacuation. All components will be pre-cleaned and also progressivelycleaned during fabrication. Final cleaning applies only to areas and procedures which may be contaminated during fabrication.

7.1 Ultra Violet Light ExaminationAll cleaned, exposed exterior surfaces, and interior surfaces to the physical extent possible, will beexamined under ultra violet lamps while in a dark or subdued light. Any evidence of fluorescence(which may indicate presence of hydrocarbons) will be cause for rejection and recleaning. Fluorescentspecks due to lint or mildly fluorescent stains from detergent residues are acceptable, except in excess.

7.1.1 Where direct ultra violet is ineffective, the wipe technique will be used. The surface will berubbed in opposite directions with a clean, white paper or lint free cloth which will then be re-exam-ined under both bright and ultra violet light. Excessive discoloration or bluish-white fluorescence willbe cause for rejection and recleaning.


6/97

© 1997

1 -21

7.2 Required RecleaningParts or assemblies rejected for cleanliness will undergo complete or spot recleaning as required. Re-examination is required after recleaning.

8.0 PACKING/SEALINGPipe ends will be sealed with polyethylene sheets or bags to a minimum of one (1) inch onto the jacket closure, and sealed with water-proof tape. Ends will then be treated appropriate to the degreeof protection required to prevent damage during shipment. This may be plywood backing flanges(flange connections), foam wrap (over the nose of bayonets), or other protection as necessary. Anadditional polyethylene sheet will be taped into place as the outermost wrap. Threaded ends will beprotected with “Ca Plugs,” or equal prior to applying the final seal. Additional packaging and sealingrequirements may be specified by engineering/design and/or customer contract.

9.0 LABELINGEach spool will be labeled with a PHPK self-adhesive, aluminum anodized (Photofoil) label. The labelwill be placed near the vacuum seal-off valve and will contain the appropriate information to identifythe spool part number, service, etc.

Spools cleaned for oxygen service will be labeled with an additional label indicating “cleaned for oxygen service.”


© 1997

1 -22


6/97

© 1997

1 -23

Cryogenic filters

DescriptionThe PHPK FA-series cryogenic filter is designed to provide the ultimate in cryogenic fluid andcold gas filtration. The filter is manufactured using 304/304L-grade stainless steel and PHPKcryogenic couplings and seal-off valves. Although PHPK vacuum insulated filter assemblies usestandard designs, each assembly is custom fabricated to meet customer needs and specifications.

Each assembly is provided with a replaceable stainless steel filter element. Options include high-point purge, low-point drain, upstream and downstream pressure taps, differentialpressure gauge, flanged or V-band connected housing, back-pressure flow protection, andliquid oxygen cleaning.

PHPK vacuum insulated filter assemblies are inspected and tested to the same high standards asall other PHPK equipment. It is designed to meet ANSI/ASME B31.3 code requirements and eachunit is pressure tested, mass spectrometer leak tested to 1 x 10-9 scc/sec helium, dimensionally andfunctionally tested, and supplied commercially liquid oxygen-cleaned. Other testing is performedas required by the customer specifications.

PHPK will assist in specification preparation and design of assemblies to meet your specificrequirements. To aid PHPK in design, please specify the following when ordering:

■ System Line Size■ Flow Rate■ System Operating Pressure■ Nominal and Absolute Micron Rating■ Permissible Clean Pressure Drop■ Back Pressure Flow Support■ Optional Hardware



© 1997

1 -24

Notes: All of the dimensions noted above are only supplied for envelope and design as each filterassembly is custom-fabricated.

In addition to other noted options, PHPK offers bolted flange connections as a replacementfor the V-band clamp, and Schedule 10 and 40 pipe connections when specified.

FA Series Filters

NPS Sch.5Filter AssemblyModel Numbers

ProcessLine Size

Dimensions in Inches

FA-050

FA-075

FA-100

FA-150

FA-200

FA-300

FA-400

GFEDCBA

1/2

3/4

1

1-1/2

2

3

4

1/2

3/4

1

1-1/2

2

3

4

2

2

2-1/2

3

4

5

6

4-1/2

4-1/2

5-9/16

5-9/16

6-5/8

10-3/4

12-3/4

14-3/4

14-3/4

20-1/2

20-1/2

21-1/4

30-1/2

39

2-1/2

2-1/2

3

3

3-1/2

9

10

5-1/4

5-1/4

6-1/4

6-3/4

6-1/4

9-1/2

10-1/2

4-1/2

4-1/2

5-1/2

6

5-1/2

8-1/2

9-1/2

C

D

E

GF

B (NPS.)

LOW POINT DRAIN(optional)

HIGH POINT VENT ORPURGE (optional)

PHPK VR-46 SERIESSEAL-OFF VALVE

V-BAND CLAMP(Flanged connectionoptional)

O-RING SEAL

FILTER ELEMENT

UPSTREAM ANDDOWNSTREAM PRESSURE TAPS(optional)

▲▲P GAUGES (optional)

A (NPS.)

Symmetrical aboutthe center line

phpk cryogenic equipment · 2004-11-05 · vacuum jacketed piping heat leak the following table...

Documents