vj piping design

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VIP Design and Installation

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  • www.chart-ind.com

    Vacuum Insulated Pipingfor

    Cryogenic ServiceSystem Design and Installation

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    Chart Industries History

    Worlds largest cryogenic design/manufacture of cryogenic equipment for over 40 years.

    Facilities Worldwide facilities including North America, Czech Republic,

    China, Germany Products

    Storage tanks, pipe, transport/delivery tanks, injectors, test chambers, controls systems, etc

    Markets Industrial gas, medical, biological, electronics, aerospace,

    automotive, restaurant, beverage, etc. Vacuum Insulated Pipe Brand Names

    MVE CVI Python

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    Types of Cryogenic Piping

    Static vacuum Section vacuums are factory sealed Very high and stable efficiency Long life expectancy Simple field installation

    Dynamic vacuum Requires continuous operation of vacuum pump Less efficient than static vacuum pipe

    Foam insulated copper Medium/low efficiency, degrades with time Lower initial cost but higher operating cost and shorter life

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    VIP Applications

    Volume related applications Nitrogen expands 700X from liquid to gas

    Refrigeration related applications LN2 temperature is 320 degrees Fahrenheit LN2 heat of vaporization is 92 BTU/#

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    VIP Applications

    Volume related applications N2 Purge gas

    Beverage & food packaging Aerospace LNG as fuel

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    VIP Applications

    Refrigeration related applications Cryo-bio storage Biological freezing Food freezing Electronics testing HALT/HASS Entertainment fog effects Super conductors Deflashing of rubber parts Cryo tempering

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    VIP Design and construction

    Sizes Rigid

    pipe size thru 10 pipe size Flex

    ID flex thru 10 ID flex

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    VIP Design and construction

    Pressure rating Normally 150 psig for LN2

    Most LN2 applications require pressures of 20-70 psig

    Normally 300 psig for LCO2 Special pressures on request

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    VIP Design and construction

    Code ASME B31.3 Process piping

    New Prague manufacturing shop approvals ASME U stamp

    Certificate #8,377 ISO-9001:2000 Quality System

    Certificate #GQC-246

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    VIP Design and construction

    Double wall vacuum insulated Nearly 400 deg F temperature differential from

    inner to outer Vacuum minimizes gas conduction and

    convection Long thin walls minimize metal conduction Multi layer super-insulation minimizes radiation

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    VIP Design and construction

    Inner pipe Outer jacket pipe End closure

    Support Internal bellows Gas trap Super-insulation

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    VIP Design and construction

    Materials Inner carrier pipe options

    Pipe, welded, schedule 5, type 304 SS Pipe, welded, schedule 5, Invar Convoluted flex, type 321 SS Specials on request

    Vacuum jacket material options Pipe, welded, schedule 5, type 304 SS Convoluted flex, type 321 SS Specials on request

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    VIP Design and construction

    Materials Super-insulation

    Multiple layers of cryogenic grade spacer paper and aluminum foil or double aluminized Mylar

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    VIP Design and construction

    Low conductivity spacers Multiple leg support of low conductivity

    composite materials Low conductivity end connections

    Bayonets are most common Field joint end transitions

    Require welding together on-site

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    VIP Design and construction When filled with LN2, SS inner pipe shrinks in

    relation to outer (jacket) pipe. 0.003 inch per inch of length (0.72 / 20).

    Bellows placed on inner line or outer jacket to compensate. Internal bellows

    Easier for on site installation Protected from damage

    External bellows Allows higher pressures Cleaner flow path

    Invar inner pipe has extremely low shrink rate Bellows not required on lines shorter than 20

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    VIP Design and construction Vacuum

    All vacuum surfaces cleaned to remove contaminates Getters installed to maintain vacuum

    Molecular sieve Palladium oxide

    Helium mass spectrometer leak testing Heating during evacuation process Vacuum retention test prior to shipment

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    VIP Design and construction Evacuation port

    Annular space overpressure relief

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    VIP Design and construction Optional Testing/Quality Measures

    Radiographic inspection (5% of butt welds) Pressure test (each section) Inspection by ASME Authorized Inspector Dye penetrant testing Material traceability

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    VIP Design considerations Cryogenic liquid

    LN2 most applications LO2 requires special components & cleaning LHE requires special components & mfg LCO2 requires higher pressure & special

    components

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    VIP Design considerations

    Design Pressure Maximum Allowable Working Pressure (MAWP) What is the pressure required by the end use application

    What is requirement right at point of use? What is the pressure drop through the pipe system? What is the pressure supply capability of the liquid

    source? What is the pressure control capability of the liquid

    source? Are there multiple use points/pressure requirements

    within the system?

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    VIP Design considerations

    Flow requirements are used to size the pipes header and drop diameter sizes: What is the end-use applications flow requirements? Do the flow requirements change over time?

    Change with pressure? How many use points are in the system? Will there be additional equipment added to the pipe

    system in the future? Consider this flow in the sizing of the main header

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    VIP - LN2 flow vs pipe size

    Length equivalent is length of pipe plus fitting factors Valve = 40 feet / Elbow or tee = 20 feet / 1 foot flex = 3 feet One foot vertical rise = 0.35 psi pressure drop for nitrogen service Based on 5 psi pressure drop

    140 GPM48 GPM25 GPM8 GPM1 GPM500160 GPM54 GPM28 GPM10 GPM2 GPM400185 GPM63 GPM32 GPM11 GPM2 GPM300

    225 GPM78 GPM40 GPM14 GPM3 GPM200325 GPM110 GPM56 GPM20 GPM4 GPM100

    3 PS2 PS1-1/2 PS1 PS PSLen Eq

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    VIP Design considerations Routing

    Define carefully because changes are difficult, time consuming and costly Useful to make the initial design, then re-visit the site with

    the drawing to confirm the design will work Be careful of obstructions (vents, electrical, pipes, etc.)

    Be sure to ask about any obstructions that may not be present at the time of design, but may be installed before the VIP is installed

    Minimize fittings to control cost (elbows, tees, bayonets, etc.)and improve system flow performance

    Flex can be used to make installation easier, or work around an obstruction such as a support beam, etc. Especially useful at connection points to the tank and/or

    end use equipment

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    VIP Design considerations Section lengths

    Longer sections generally reduce total system cost and heat leak

    20 foot sections are optimal for manufacturing and shipping

    Consider installation issues Moving into building, lifting, walls, etc.

    Consider shipping May consider section breaks in places to accommodate a

    future addition in specific places There are some minimum dimensions for various fittings

    based on manufacturing requirements

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    VIP Design considerations Section connections

    BayonetsShrink fit design - MVEClose tolerance design - CVIField joints

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    VIP Design considerations

    O-ring

    Female bayonet (sectioned)Clamp

    Shrink fit nose Male bayonet

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    VIP Design considerations

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    VIP Design considerations Vacuum jacketed valves

    Y-PatternT-Pattern

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    VIP Design considerations Non-jacketed cryogenic valves

    Although they are not vacuum insulated, they still need to have an extended stem so that the resulting ice ball does not grow to the valve packing When valve packing gets too

    cold, it could leak nitrogen to the environment

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    VIP Design considerations

    Gas traps Used in intermittent use drops to

    control heat leak and frost. Allows use of non-VJ valves. Not recommended for high flow

    applications due to its pressure drop Not recommended for continuous

    use applications

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    VIP Design considerations End connections

    Bayonets Most efficient Easy to install

    Pipe threads Will result in ice ball Readily available connections to various equipment

    ANSI flanges Will result in ice ball Need to use low temperature gasket material

    Pipe stub ends Will result in ice ball Requires welding on-site at installation

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    VIP Design considerations Relief valves & risers

    Relief valves are required in any spot where liquid can be trapped (between any two valves) Consider protection at the inlet and outlet of the pipe system

    Does the supply/use equipment have protection? Confirm pressure rating of relief valve needed

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    VIP Design considerations

    Future expansion Less expensive to add futures than to modify

    or replace system later Consider future expansion when sizing pipe Typically accommodated by placing a caped

    bayonet at location where expansion may take place.

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    VIP System Measurement Location of tank and use points Architectural structure of building Locate clearest path from tank to use points Establish elevations Design system with maximum length sections

    minimizing elbows & tees Establish flow rates to support pipe sizing Establish use pattern

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    VIP System Measurement Establish saturation pressure requirement at use

    point Combine design, sizing and flow to establish

    pressure drop Recommend tank operating pressure Measure and document the pipe routing Establish installation procedures and material /

    equipment list

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    VIP System Installation

    Off loading the truck Watch for damage

    Notify driver and document any damage immediately before driver leaves!

    Consider checking section vacuums

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    VIP System Installation

    Reading the print and assembling the puzzle Isometric drawing not to scale Section numbers on print match section

    numbers on labelsVS-1, VS-2, VS-3, etc

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    VIP System Installation

    Supports / hangers Support every 10 feet J-hangers or cushioned pipe clamps

    Uni-strut (www.tyco-unistrut.com) Flex-strut (www.flexstrut.com)

    External bellows pipe needs to be able to move along its axis

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    VIP System Installation

    Installation equipment & supplies Halocarbon grease to lubricate bayonet o-rings Standard hand tools (wrenches, small hammer) Consider need for manlift, forklift, crane Field joints require welding and evacuation

    equipment

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    VIP System Installation

    Installation labor Generally need at least two people to install any

    systemSystems with longer sections, bigger

    diameters, many sections, welding, etc will require more people on-site

    System with bayonets require less time and skill System with field joints require welding and

    evacuation

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    VIP System Installation Proper bayonet assembly

    Clean and inspect bayonets Lubricate and install o-ring Engage bayonets (do not twist) Install V-retainer and tighten nut Bayonets should slide together easily

    If it is difficult, it is likely due to not having the pipe sections aligned properly

    Do NOT force them together

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    VIP System Installation

    Proper slope If the system contains a Cryovent to keep the

    pipe filled with liquid, the pipe must rise continuously towards the Cryovent.Any gas bubbles must rise to the CryoventAny high spots will trap gasRise ~1 per 50

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    VIP System Installation

    Pressure / leak test Do not exceed MAWP of pipe If testing at more than 90% of MAWP,

    temporarily replace relief valves Use clean, dry gas, preferably nitrogen Leak test all joints or do pressure decay test

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    VIP System Installation

    Start up Preferably isolate Cryovents Fill slowly to minimize pressure spike Open use point valves until there is a continuous

    stream of liquid It will be several hours before system is stable Once system is stable, open cryovents

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    VIP System Installation

    Maintenance Monthly visual inspection of piping

    Look for sweating, frost and leaksCheck relief valves (installed & set point)

    If there are questions or issues, call ChartProvide PN and VS number from label

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    VIP System Installation

    Maintenance Before disconnecting any bayonet or

    component, verify that all pressure has been released for the system.

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    VIP Accessories Cryovent

    Keeps the VIP system filled with LN2 during periods of no useage Provides quick response when the system needs

    liquid Float driven valve Installed on tee, at highest point, near use point Pipe must rise continuously towards Cryovent

    Gas bubbles must get to the Cryovent

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    VIP Cryovent

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    VIP Accessories APPS-160 Phase separator

    Allows using a single storage tank to supply a high pressure GN2 application and a low pressure LN2 application Lowers pressure of LN2 Sits next to supply tank Outlet Feeds VIP system with

    a vacuum insulated bayonet connection

    Operates up to 50 psig 15 GPM max

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    Python Pipe

    Python Pipe Product Good alternative to foam insulated copper pipe 1 & 2 pipe size in stock, 3 special order Straight, rigid lengths from 2 to 20 (even feet) Flex sections with 6 of flex Pre-insulated cover kits in straight, elbow & tee

    configurations

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    Python Pipe

    Higher heat leak means higher cost of operationEnd use system is much more efficient for customer, providing higher quality liquid and reducing losses

    Foam insulation should be stripped off and re-applied to keep its efficiency

    Extremely low maintenance

    Plastic outer jacket and foam is easily damagedStainless steel outer jacket for durability and aesthetics

    Over time will condense moisture on outer jacket and ultimately may grow mold

    Will not condense moisture on outer jacket

    Foam insulated pipe requires significantly larger OD for the insulation, requiring more space and higher cost of installation (wall penetrations and supports)

    Smaller outer jacket means less space required for the installation and less cost for wall penetrations and pipe supports

    As moisture leaks past the plastic cover, it soaks into the foam making it even less efficient. Eventually need to replace the foam!

    Stainless steel outer jacket is not affected by moisture from ambient

    Poor-moderate thermal performanceExcellent thermal performance (at least 5 times better than foam)

    Foam Insulated PipePYTHON

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    Standard Python Joints

    T-joint

    Elbow joint

    Straight joint

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    Python pipe

    Design Inner & outer stainless steel pipe, schedule 5 Static vacuum factory evacuated and sealed Field welded, pipe stub end joints

    All weld joints are insulated in the field 400 psig MAWP

    External bellows design

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    Python pipe

    System design considerations Even foot increments Minimize joints to maximize efficiency Over-all length will shorten 3-1/2 per 100 when

    filled with LN2Consider this when providing installation

    Wall/roof penetrations Connections to equipment

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    Python pipe

    Installation Hang sections Weld joints (manual TIG on schedule 5 SS pipe) Leak test joints Install joint covers