Cryogenic scheme, pipes and valves dimensions U.Wagner CERN TE-CRG

Topics  Introduction  SPL constraints  Cryogenic scheme  Evolution since 2009  Scheme for the short module  Aspects to be tested in SCM  Pipe and valve design  Definition basis  Results  Overpressure protection  Important but unfinished

SPL constraints  Design has to accommodate with the following constraints.  Geometrical  Slope of 1.7 %  Thermal  Design heat load Still there! Important for cool-down and fill system Heat load [W] Temperature level [K] Nominal pressure [bar] Nominal mass flow [g/s] Thermal shield Coupler cooling(1120) K static load K total load

Module Schemes 6/11/2009 SPL Workshop Nov Scheme no 6 : “ILC like SPL version “A” with separate cryogenic feeder line” LP SPLHP SPL Diameter “x” [mm] % Deleted: cold magnets, line “A”, 1 phase separator Modified: Coupler cooling from 5-8 K to K Slide presented in Workshop Nov 2009

Reference SPL module 2011 Reference 2011 probably not final !

SPL short module Additional valves to test feasibility of 2 K supply scheme Cool down valves; tests should show if necessary

Piping and valve design Definition basis  Short module cryostat as integration test for full- size high-  module  Piping and valve dimensioning as for full-size high-  module  Where reasonable!  General remark:  The design has “reasonable margins”.  Principally we want to test cavities not piping limits.

Piping and valve design Definition basis Heat load [W] Temperature level [K] Nominal pressure [bar] Nominal mass flow [g/s] Thermal shield Coupler cooling(1120) K static load K total load Heat loads for SPL high-  module Static load estimated to 2.5 % of total load. Even half or double the static load has no influence on design. Assessment of static load is of minor importance at this state.

Piping design  Design basis:  80 mm hydraulic diameter for the transport of 25 W over about 1 m length  Value: Line “L”: 410 mm Di  Value: Line “Y”: 80 mm Di Line “L”: cavity helium enclosure Line “Y”: cavity top connection Line “L”: Helium tank Line “Y”: Cavity top connection

Piping design  Design basis:  Vapour flow speed < 7 m/s to avoid drag of liquid  Low pressure loss for isothermal cavities  Value: 80 mm Di  15 m line; 10 g/s;  p = 0.07 mbar;  T(  p) = 0.08 mK; vapour speed = 2.7 m/s Line X: 2-phase pipe Line “X”: 2-phase pipe

Piping design  Design basis:  Pressure drop for 2 K gas pumping  Value: 80 mm Di  5 m line; 10 g/s;  p = 0.02 mbar Line XB: Pumping line Line “XB”: Pumping line

Piping design  Design basis:  Pressure drop for K gas  30 m length  Value: 15 mm Di  Nominal:  inlet: 50K, 16 bar; 30 m line; 2 g/s;  p = 2 mbar Lines E and E’: Thermal shield supply and return Line E, E’: Thermal shield line No heating foreseen from 5 K to 50 K in SM 18 supply!  Short module:  inlet: 50K, 1.2bar; 15 m line; 2 g/s; Dp = 18 mbar  inlet: 5K, 1.2bar; 15 m line; 0.65 g/s; Dp = 1.5 mbar

Piping design  Design basis:  Cool-down; no requirements exist!  Assumption: 2.5 g/s per cavity 5K; 1.3 bar available  p: 100 mbar  15 m length  Value: 6 mm Di  Cold: 5K, 1.3 bar; 2.5 g/s;  p = 90 mbar  Warm: 285, 1.3 bar; 0.17 g/s;  p = 104 mbar Lines C1: Cavity filling Line C1: Cavity filling

Piping design  Design basis:  Nominal operation, but full flow over whole length  15 m length  Value: 6 mm Di  Cold: 5K, 1.1 bar; 0.8 g/s;  p = 13 mbar Lines C2: Coupler cooling Line C2: Coupler cooling

Piping design  Design basis:  Nominal operation, single supply line for all cavities  15 m length  Value: 10 mm Di  Cold: 2K, 0.03 bar; 10 g/s;  p = ~50 mbar Lines C3: Cavity top connection Line C3: Cavity top connection

Piping design Updated table Minimum values

Valve design  Valve design for the conditions found during the test of the Short module in SM18  Not for a full scale SPL module in a SPL machine.  Each valve has margin on nominal Kv value  Good practice, not to be stuck with self imposed limitation

Valve design Design caseNominal 8 cavities Nominal 4 cavities Static load 8 cavities Static load 4 cavities Inlet conditions Pressure[bar]1.5 Temperature[K]2.3 Flow[g/s] Outlet Pressure[bar] Kv value[m 3 /h] Common JT valve Maximum Kvs at 100% stroke:0.1 Kv at 5% stroke:0.001 Rangeability:100 Valve characteristic:Equal percentage or linear Typical: DN 4 / DN6 ~ x 2

Valve design Design caseNominal load single cavity Static load 4 cavities Inlet Pressure[bar]1.5 Temperature[K]2.3 Flow[g/s] Outlet Pressure[bar]0.032 Kv value[m3/h] Single JT valve Maximum Kvs at 100% stroke:0.02 Kv at 5% stroke:0.001 Rangeability:50 Valve characteristic:Equal percentage or linear Typical: DN2 / DN4 ~ x 2

Valve design Design caseMax. CD at 5 K Inlet conditions Pressure[bar]1.5 Temperature[K]5 Flow[g/s]2.5 Outlet conditions Pressure[bar]1.2 Kv value[m 3 /h]0.126 Cool-down and fill valve Maximum Kvs at 100% stroke:0.18 Kv at 5% stroke:0.004 Rangeability:50 Valve characteristic:Equal percentage or linear Typical: DN4 ~ x 1.4

Valve design Design caseNominal 8 cavities Nominal 4 cavities Inlet conditions Pressure[bar]1.5 Temperature[K]4.7 Flow[g/s] Outlet conditions Pressure[bar]1.2 Kv value[m 3 /h] Coupler cooling supply Maximum Kvs at 100% stroke:0.06 Kv at 5% stroke:0.002 Rangeability:50 Valve characteristic:Equal percentage or linear Typical: DN2; mainly shut-off function ~ x 4 (valve very small)

Valve design Design casePowered coupler Unpowered coupler Inlet conditions Pressure[bar]1.1 Temperature[K]280 Flow[g/s] Outlet conditions Pressure[bar]1.05 Kv value[m 3 /h] Coupler cooling return Maximum Kvs at 100% stroke:0.08 Kv at 5% stroke:0.01 Rangeability:10 Valve characteristic:Equal percentage Typical: DN2; ambient temperature valve ~ x 2~ ÷ 2

Overpressure protection  Operational system failures  E.g. sudden stop of pumping, wrong opening of valves.  Frequent, relatively low flow  Spring loaded safety valves  Defining the safety valves  Mechanical system failures  E.g. break down of insulation or beam vacuum  Rare, relatively high flow  Rupture disks  Defining rupture disk and conduct System failures

Overpressure protection  Defining case for safety element AND conduct  Safety element outside cryostat  Conduct inside cryostat  Conduct may be part of the piping discussed above.  In the following conduct = 2-phase header & pumping line  Rupture of insulation vacuum  Widely accepted design criteria  Exact geometrical data missing, but approximately known  Rupture of beam vacuum  Design criteria not precisely known  Exact geometrical data known since Mechanical system failures

Overpressure protection  Insulation vacuum rupture SCM  Flow: ~ 1000 g/s per cavity  Pressure loss conduct: (80 mm, 7 m) 35 mbar  OK for rupture disk > 65 mm  Insulation vacuum rupture SPL  Flow: ~ 1000 g/s per cavity  Pressure loss conduct: (80 mm, 15 m) 330 mbar  Conduct not sufficient!  Solution 1: Increase conduct to 120 mm  Solution 2: two rupture disks at both ends First estimates

Overpressure protection  Beam vacuum rupture SCM  Based on: 64 l He and 1.75 m2 surface / cavity.  Flow: ~ 2700 g/s per cavity  Pressure loss conduct: (80 mm, 7 m) 250 mbar  Conduct not sufficient!  Solution 1: Increase conduct to 120 mm  Solution 2: Two rupture disks at both ends  Two rupture disks for SCM are proposed First estimates Not widely accepted!

Overpressure protection  Beam vacuum rupture SPL full scale  Still many open questions:  Pressure inside cavity at beam vacuum loss  Pressure inside at peak heat load  Heat transfer at beam vacuum loss  Time for filling a string of eight cavities  Cannot be answered yet  Remark:  These questions are as well valid for the Short module.  The proposed approach allows to continue. First estimates

SPL short module Conduct Rupture disk Additional rupture disk