Standard - WEKA AG

WEKA AG, CH-8344 Bäretswil & CH-2300 La Chaux-de-Fonds, Switzerland 

Phone +41 43 833 4343 - Fax +41 43 833 4329- Schürlistrasse 8, CH-8344 Bäretswil 

Phone +41 32 925 97 00 - Fax +41 32 926 54 22 - Allée du Quartz 1, CH-2300 La Chaux-de-Fonds 

WEKA Specification no. 19911004 – WEKA Cryogenic Valves 

info@weka-ag.ch - www.weka-ag.ch 

19. September 2007 - FHo / Page 1 of 7 

1. Introduction 

WEKA Cryogenic Valves are designed to meet the special requirements for cryogenic plants for Helium (He) or 

Hydrogen (H 2 ). Operating temperatures goes down to 2.2K and lower. Fluids are therefore in gas, liquid or even 

superfluid (HeII) state. However valves could also be used in applications with other cold liquefied gases like 

Neon (Ne), Nitrogen (N 2 ), Argon (Ar), Oxygen (O 2 ) etc. 

2. Valve Description 

WEKA Cryogenic Valves are available as 

a) Bellows sealed valves followed by a security back-up sealing and a plugged leak test port. This high quality 

sealing system guarantees for highest tightness and safety under pressure and vacuum conditions. Preferable 

it will be used for low density fluids like He and H 2 . Also for high purity gases it is recommended to use 

bells sealed valves. 

or 

b) Packing sealed valves with an elastomeric quad-ring for applications which have reduced requests on tightness 

e.g. for fluids like Nitrogen (N 2 ), Air etc. however could also be used for low density gases. 

Static seal to outside between valve body and bonnet and inset respectively is made with an elastomeric o-ring 

joint at the warm top end of the valve. O-ring joint grooves are designed for pressure and vacuum conditions. 

For sub-atmosphere service conditions e.g. in superfluid HeII a double o-ring joint with a guard gas connection is 

available. 

The valve seat is integrally machined into the valve body at the cold bottom end. It will be closed by a polymeric 

soft seal. The cardanic stem inset design guarantee seat tightness over the full temperature range. Some 

movement by thermal contraction of the piping could be compensated. Seal heads of valves size >= DN20 are 

spherical flexible joined to the inset. Smaller valves have elastically buckling spindle tubes. 

Seat tightness and flow control functions are cut by the design and adaptable to any specifications required. 

Exact tolerances of the valve bore made it possible to use for both, on/off- (digital-) and control applications. For 

control valves appropriate standard flow plugs with either equal- % or linear flow characteristics are available 

(see cat. no. 921101). Plugs with any special flow characteristics are possible on request. Digital valves will be 

equipped with a flow trim which assures highest possible k v -value (c v =1.16* k v value). For details regarding valve 

bore and travel as well as for k v - / c v -values see table ”Technical Valve Data’s”. 

To change either seat seal or flow plug, the stem inset is retractable through the body on the top end. 

Valve body and inset are a welded design with forged and tube stainless steel which guarantees a great operational 

reliability of service and highest possible tightness. 

Depending on valve size (DN) following standardised cryogenic length “h” are available. However all lengths 

between a minimum length, which depending on lowest service temperature and on valve size DN, up to a max. 

of about 2000mm or more are available. For longer length requests a special design with compensating bellows. 

To reduce the heat load by thermal conductivity of solids, the wall thickness for body and inset tubes are optimised 

regarding pressure and shut-off loads. Stem inset intersection tubes have a Perlite powder filling to prevent 

convective heat in-leaks. 

For further reduce of heat loads, a Cu-thermal flange could be brazed to body pipe to contact a cooling shield. 

Available are also compound valve stem insets with a vented GFK intersection tube. This design reduce the 

indicated heat load values (see page 7) of about 30 to 40% for valves size DN10 and greater. Available are also 

vented stainless steel inset tubes filled with a stainless steel or polymer netting. 

If there is a risk of thermo acoustic oscillations in the ring section of body and inset pipe, which is kept as small 

as technically possible, optional available is the fitting of a convection brake. 

Standard cryogenic valves are equipped with a vacuum weld-in flange for cold-box mounting from the bottom 

side. Flanges with greater diameter for assembling through top plate are optional available. On request possible 

are any other vacuum flange assembling. However valves without weld-in flange are also available as well as on 

request vacuum jacketed valves. 

L:\_Dokumentationen\Cryo_Datenblätter\_Originale\19911004-E-2002.doc







The valve actuator spindle is flexible clutched on the bellows inset. This design guarantees an optimised 

adaptability to any functions requested and protect the valve against any inaccuracies from the actuator. A manual 

drive or pneumatic, electrical or hydraulic actuator could be fitted. 

Beside the possibility to turn the actuators in any circumferential position - in case of restricted space on cold box 

plates - it also allows a later modification of actuators on mounted valves to fulfil new functions. 

3. Valve Actuators 

WEKA Cryogenic Valves are supplied with manual, pneumatic or electrical actuators for on/off (digital) or control 

functions. Actuator control accessories like limit switches, positioner, 3/2-way solenoid valves etc. are selected 

according to the specified valve function. 

Pneumatic and electrical actuators as well as their accessories are bought from selected proven manufacturers. 

However, all current products, as per the customer’s request, could be assembled on request. Also available are 

pneumatic- or hydraulic piston drives. 

Actuator size and system is derived by the valve size (DN), the specified service or shut off pressure pressure, 

the available supply of energy (air pressure, power) and the plant control system. Also to act are specifications 

about actuating time, fail function in case of loss of energy supply and other restrictions like x-ray radiation's or 

explosion proof areas. 

4. Manufacturing and Quality Assurance 

Based on our long-standing experience in design, manufacturing and testing of Cryogenic Components we are 

in a position to offer you a made-to-measure solution for almost any requirement. 

Apart from the latest state of the art production equipment such as CAD-systems, fully integrated PPS with online 

BDE-system, CNC machine tools, TIG- (GTAW) welding equipment as well as He-leak tightness detector, 

ultra-sonic cleaning bath and separated assembling and testing rooms, we also maintain a appropriate QAsystem. 

The welding shop is qualified according to EN-, SVTI-, AD- and ANSI/ASME codes. 

WEKA Cryogenic Valves are individually He- leak tested over the valve seat and to outside, both under vacuum 

and pressure conditions. Valve bodies additionally are hydrostatic- or gas pressure tested. All these tests are 

executed, if possible, on the completely fitted valve and according to written procedures specifications. 

A end check of all valve function, dimensions, completeness of all accessories as well as adjusting of actuators 

and cleanliness of fluid contacted surfaces is carried out prior to despatch. 

For despatching the valves are packed in PE bags. 

All tests indicated above are specified in detail in the "Standard Delivery Specification for Cryogenic- and Bellows 

Sealed Valves" 

Additional tests and inspections according to customer’s request will be possible. 








Technical Valve Data's 

4.1 Valve 

Valve size DN 

(Nominal Valve Size) 

Valve bore / Valve travel 

k v s value range as control 

resp. digital valve 

(c v =1,16 * k v ) 

i.e. different flow plugs for k v s 

value range, see catalogue 

no. 921104 

PN 

(Nominal Pressure 

==> max barg @ 20°C) 

Standard 

Heat load to the system See page 7 

Size DN Dia. of valve bore Valve travel 

(mm) 

(mm) 

DN2 2mm / 10mm 




DN10 10mm / 10mm 

DN15 15mm / 10mm 

DN20 20mm / 16mm 

DN25 25mm / 16mm 

DN32 32mm / 16mm 

DN40-36 36mm / 20mm 

DN40 40mm / 32mm 

DN50 50mm / 32mm 

DN65 65mm / 32mm 

DN80 80mm / 40mm 

DN100 100mm / 50mm 

DN125 120mm / 65mm 

Size DN as control valve as digital valve 

DN2 0.007...0.070 lin - 

DN4 0.050...0.186 lin - 

DN6 0.09...0.80 =% 0.9 dig 

DN8 0.20...2.20 =% 2.5 dig 

DN10 0.33...2.80 =% 3 dig 

DN15 1.00...5.80 =% 6 dig 

DN20 5.3...11.0 =% 12 dig 

DN25 6.8...14.7 =% 15 dig 

DN32 12.6...21.8 =% 25-dig 

DN40-36 16.0...33.0 =% 35 dig 

DN40 20.6...43.3 =% 45 dig 

DN50 31.5...71.0 =% 75 dig 

DN65 52...98 =% 100 dig 

DN80 63...160 =% 170 dig 

DN100 ...240 =% 260 dig 

DN125 ...370 =% 390 dig 

PN25 as standard respective PN… as 

indicated 

i.e. same valve could be used as PN6, PN10, 

PN16 and PN 20 respectively 

Body and bellows are designed for 25bar, for 

details see specification no. 930922 (pressure 

load calculation) 

Optional on request 

Greater DN on request 

Longer travel on request, special diameter 

on valve bore on request e.g. 

Size DN Dia. of valve bore Valve travel 

(mm) 

(mm) 

DN150 140 / 70 

DN200 190 / 95 

DN250 240 / 120 

DN250spez. 270 / 135 

DN300 285 / 145 

k v s







Valve Interface Connections 

Valve body pattern 

Cat. no. 911003 

Pipe Connection 

Cat. no. 911003 

Mounting 

Cryogenic length 


Angle 

Butt weld ends 

Standard weld- in flange for coldbox 

mounting, according to catalogue no 

910930 and 911031 

Without weld-in flange according to 

catatalogue No. 911104 

Depending on DN and service temperature, 

h=600, 875, 1000 and 1300mm 


Globe pattern (D- or Z-shape) 

Y - pattern, 45° 

Flanges, tube fittings etc 

KF-flanges or any other flange 

according to customer’s request. 

Vacuum jacketed etc. 

all dimensions between min. h and 

up to max. of. ca. 2000mm 

4.2 Materials 

Body 

Inset 


Stainless steel code 316L i.e. 

DIN grades 1.4404, 1.4432 or 1.4435 

(DIN17440, DIN17457 and DIN 17458 

as well as new EN10272, EN10217 

and EN10216) 

Stainless steel code 316L i.e. 

Insert tube filled with Perlite powder 

and tight welded 


Stainless steel code 321 (DIN 

grades 1.4541 / 1.4571) or code 

304L (DIN grades 1.4306/1.4307) 

Compound design with FWG Epoxy 

-glass fibre tube, vented and 

filled with PE-netting or ss netting. 

Vented stainless steel tube filled ss 

netting. 

Seat seals PTFE or PCTFE or HD-PE1000, PI, PEEK mod., Ni, Stellite 6 

Flow plugs CuAl10 Fe Ni5 Stainless steel polished 

Bonnet, union nuts 

Upper spindle 

Brass up to DN65 

Stainless steel grade A2 >=DN80 

Stainless steel grade A2/A4 

In stainless steel A2 

Static O-ring joints NBR70; FPM75 Kalrez / Chemraz etc. 

Stem sealing: 

Bellows sealed: 

Packing sealed: 

Manual drive: 

Stainless steel grade 316L i.e. 

DIN grades 1.4404 and 1.4435 

Security seal: 

= DN80 PTFE chevron packing 

NBR quad ring, guiding in PTFE 

Hand wheels and travel indication in 

Aluminium 

Yoke and legs in Stainless steel 

grade A2/A4 

FPM o-rings 

other packing 

FPM quad ring, guiding in HD- 

PE100 








5. Valve Actuators: 

Manual Drives: 

− Integral or leg design, precision drive 1/100 backlash for control functions 

− Manual drives with fine travel indication for control or rough indication for shut-off only 

− Possibility to fit switches (electromechanical or inductive) to indicate valve (end) positions 

− For dimensions see catalogue-no. 921029 

Pneumatic Actuators 

− Pneumatic diaphragm actuators for on/off (digital)- or control functions, max. air supply pressure depending 

on actuators type up to 6,0 barg respectively 4,2barg, min. air supply pressure depending on valve size, position 

in case of loss of air pressure or signal and service or shut-off pressure 

− Normally closed or normally open by spring thrust 

− Control valves with electropneumatic positioner, with 

⇒ conventional analogues positioner, signal 4-20mA 

or with 

⇒ intelligent digital positioner, signal 4-20mA with option modules for 

• alarms (incl. 2-off adjustable travel switches, 1-off configurable alarm outlet and 1-off binary inlet configurable 

for use for examples as 3/2-way solenoid valve or blocking valve) 

• analogues travel feedback as 4-20mA signal 

• HART protocol 

or with 

⇒ intelligent digital positioner for fieldbus technology, system PROFIBUS PA, with all optional as described 

above 

or with 

⇒ pneumatic positioner signal 0,2 - 1,0 barg, integral 

− Positioner will be side mounted as standard, integral conventional analogues electropneumatic and for 

pneumatic positioner are available on request. An optional compact mounting for the intelligent digital positioner 

will be available on request. 

− Auxiliaries like limit switches (micro, inductive- and capacitive proximity switches), 3/2 way solenoid valves 

and any other pneumatic air control equipment according to the valve function and customer’s request. Dimensions, 

specifications and materials on request 

Electrical Actuators 

− Electrical linear actuators for on/off (digital)- or control function. 

− Power supply 220/240V-50Hz or 110V-50Hz, 24V-DC etc. 

− Depending on valve function with thrust load depending limit switches, travel depending switches and travel 

feedback potentiometers or with integral electronically positioner signal 0/4-20mA or 0-10V and any other 

electrical control equipment will be available on request 

Other Actuators 

− Pneumatic piston actuators, hydraulic or fluid self-controlled actuators according to customer’s request. 








Heat load by thermal conductivity of solids on cryogenic valves PN25 (Standard) 

Heat load for any cryogenic length “h”: 

I 

L(h = ) 

IL(h = 875,300 K − K) × 875 

= 

( W ) 

h = 

h 

(mm) 

DN2, DN4, DN6 600 

875 

DN8 600 

875 

DN10 600 

875 

DN15 600 

875 

DN20 600 

875 

DN25 600 

875 

DN32 600 

875 

DN40-36 600 

875 

DN40 600 

875 

DN50 600 

875 

DN65 600 

875 

DN80 875 

1000 

DN100 875 

1000 

DN125 875 

1200 

DN150 875 

1200 

I L (300K-4K) 

(W) 

0.28 

0.19 

0.42 

0.29 

0.48 

0.33 

0.69 

0.47 

0.94 

0.64 

1.37 

0.94 

1.54 

1.06 

2.19 

1.50 

2.92 

2.01 

3.79 

2.60 

5.35 

3.67 

5.24 

4.58 

7.35 

6.41 

10.08 

7.24 

14.51 

10.39 

I L (300K-20K) 

(W) 

0.27 

0.19 

0.41 

0.28 

0.47 

0.32 

0.68 

0.46 

0.93 

0.63 

1.36 

0.93 

1.53 

1.05 

2.18 

1.49 

2.91 

1.99 

3.77 

2.59 

5.32 

3.65 

5.21 

4.56 

7.31 

6.37 

10.03 

7.21 

14.44 

10.34 

I L (300K-77K) 

(W) 

0.25 

0.17 

0.37 

0.26 

0.43 

0.30 

0.62 

0.42 

0.84 

0.58 

1.23 

0.84 

1.38 

0.95 

1.97 

1.35 

2.62 

2.33 

3.40 

2.33 

4.79 

3.29 

4.69 

4.11 

6.65 

5.79 

9.14 

6.56 

13.18 

9.42 








Heat load by thermal conductivity of solids on cryogenic valves PN10 

h 

(mm) 

DN80 (875) 

1000 

DN100 (875) 

1000 

DN125 (875) 

1200 

DN150 (875) 

1200 

DN200 (875) 

1500 

DN250 (875) 

1500 

DN250-spez. (875) 

1500 

DN300 (875) 

1500 

I L (300K-4K) 

(W) 

(4.72) 

4.11 

(6.11) 

5.29 

(7.82) 

5.56 

(ca. 11) 

ca. 7.5 

(ca. 18) 

ca. 10 

(ca. 30) 

ca. 14 

(ca. 44) 

ca. 17 

(ca. 60) 

ca. 20 

I L (300K-20K) 

(W) 

(4.70) 

4.09 

(6.08) 

5.27 

(7.78) 

5.53 

(ca. 11) 

ca. 7.5 

(ca. 18) 

ca. 10 

(ca. 30) 

ca. 14 

(ca. 44) 

ca. 17 

(ca. 60) 

ca. 20 

I L (300K-77K) 

(W) 

(4.31) 

3.75 

(5.60) 

4.85 

(7.16) 

5.07 

(ca. 10) 

ca. 6.5 

(ca. 16) 

ca. 9 

(ca. 28) 

ca. 13 

(ca. 42) 

ca. 16 

(ca. 57) 

ca. 18 

Values above are available for the standard range of cryogenic valves. For thermal contact to shield cooling see 

catalogue no. 930435. Compound valve inset design with GFK intersection tube for further reduction of heat load 

(of about 30 to 40% depending on size of valve) on request. Values for heat load on request. 


WEKA AG 

Schürlistrasse 8, CH-8344 Bäretswil, Switzerland, Europe 

E-mail: info@weka-ag.ch / Tel.: ++41 (0)1 939 29 59 / Fax: ++41 (0)1 929 39 63 

Standard Cryogenic Valve PN25, Bellows Sealed, with Pneumatic Actuator 

- Design pressure for body and bellows inset: PN25 resp. PN10 as indicated i.e. also possible to use as PN6, PN10, PN16 and PN20 valves respectively 

- With pneumatic diaphragm actuator for a shut-off pressure as indicated 

- Control valves with digital electropneumatic positioner (digital pneumatic with electronical control) 

Nominal Valve Size DN: 2 4 6 8 10 15 20 25 

Nominal Pressure for Valve Body /Inset PN: PN25 PN25 PN25 PN25 PN25 PN25 PN25 PN25 

( = nominal pipe size): 1/12" 1/8" 1/4" 3/8" 3/8" 1/2" 3/4" 1" 

Seat diam. (mm): 2 4 6 8 10 15 20 25 

Travel (mm): 10 10 10 10 10 10 16 16 

kv max. (m 3 /h, H 2 O, D p=1bar): (Cv = 1.16*kv, Cv in US gal/min, H 2 O, ∆p=1psi) 

- Control Valve:

Nominal Valve Size DN: 

Nominal Pressure for Valve Body /Inset PN: 

( = nominal pipe size): 

Seat diam. (mm): 

Travel (mm): 

kv max. (m 3 /h, H 2 O, D p=1bar): 

- Control Valve: 

- Digital (Shut-Off-) Valve: 

Valve: 

Dia. vacuum weld in flange, cat. No. 910930, a1 (mm): 

Dia. vacuum weld in flange, cat. no. 9110031, a2 (mm): 

Butt weld end, Dia. d*s (mm) 

e (mm): 

f (mm): 

Cryogenic length h (mm): 

Heat load 300 to 4K @ indicated length h (W): 

Pneumatic Diaphragm Actuator: 

Max. shut-off pressure (bar): 

Type: 

Dia. MA (mm): 

y (mm): 

z (mm): 

Control pressure min/max. for Po actuators (barg): 

Control pressure min/max. for Ps actuators (barg): 

Remarks: 








32 32 40 40 40 40 50 50 

PN25 = PN25 = PN25 = PN25 = 

1 1/4" = 1 1/2" = 1 1/2" = 2" = 

32 = 36 = 40 = 50 = 

16 = 20 = 32 = 32 = 

(Cv = 1.16*kv, Cv in US gal/min, H 2 O, ∆p=1psi) 

14.7 = 33 = 45 = 71 = 

15 = 35 = 50 = 75 = 

80 = 120 = 120 = 120 = 

134 = 164 = 164 = 164 = 

42.4*2.0 = 48.3*2.0 = 48.3*2.0 = 60.3*2.0 = 

80 = 100 = 100 = 100 = 

101 = 106 = 106 = 106 = 

875 = 875 = 875 = 875 = 

1.06 = 1.50 = 2.01 = 2.60 = 





Travel (mm): 




Valve: 




e (mm): 

f (mm): 





Type: 

Dia. MA (mm): 

y (mm): 

z (mm): 



Remarks: 








65 65 65 80 80 80 

PN25 = = PN10 PN25 = 

2 1/2" = = 3" 3" = 

65 = = 80 80 = 

32 = = 40 40 = 


98 = = 160 160 = 

100 = = 170 170 = 

150 = = 190 190 = 

200 = = 260 260 = 

76.1*2. = = 88.9*2.6 88.9*2.6 = 

125 = = 155 155 = 

115 = = 120 120 = 

875 = = 1000 1000 = 

3.67 = = 4.11 4.58 = 





Travel (mm): 




Valve: 




e (mm): 

f (mm): 





Type: 

Dia. MA (mm): 

y (mm): 

z (mm): 



Remarks: 








100 100 100 100 125 125 125 

PN10 PN25 = = PN10 PN25 = 

4" 4" = = 5" 5" = 

100 100 = = 120 120 = 

50 50 = = 65 65 = 


240 240 = = 370 370 = 

260 260 = = 400 400 = 

230 230 = = 275 275 = 

315 315 = = - - = 

114.3*2.6 114.3*2.6 = = 139.7*s 139.7*s = 

175 175 = = 200 200 = 

133 133 = = 145 145 = 

1000 1000 = = 1200 1200 = 

ca. 5.5 6.41 = = 5.56 7.24 = 





Travel (mm): 




Valve: 




e (mm): 

f (mm): 





Type: 

Dia. MA (mm): 

y (mm): 

z (mm): 



Remarks: 








150 150 150 150 

PN10 PN25 = = 

6" 6" = = 

ca. 140 ca. 140 = = 

ca. 70 ca. 70 = = 


ca. 550 ca. 550 = = 

ca. 600 ca. 600 = = 

ca. 325 ca. 325 = = 

- - = = 

168.3*s 168.3*s = = 

ca. 250 ca. 250 = = 

ca. 160 ca. 160 = = 

1200 1200 = = 

ca. 7.5 10.39 = = 





Travel (mm): 




Valve: 




e (mm): 

f (mm): 





Type: 

Dia. MA (mm): 

y (mm): 

z (mm): 



Remarks: 








200 200 250 250 250spez. 300 300 

PN10 PN25 PN10 PN25 PN10 PN10 PN25 

8" 8" 10" 10" 10" 12" 12" 

190 190 240 240 270 285 285 

95 95 120 120 135 145 145 


ca. 930 ca. 930 ca. 1550 ca. 1550 ca. 2050 ca. 2300 ca. 2300 



- - - - - - - 

219.1*s 219.1*s 273.0*2.9 273.0*2.9 273.0*2.9 323.9*3.2 323.9*3.2 



1500 1500 1500 1500 1500 1500 1500 

ca. 10.0 t.b.a. ca. 14.0 t.b.a. ca. 17.0 ca. 20.0 t.b.a. 

t.b.a. t.b.a. t.b.a. t.b.a. t.b.a. t.b.a. t.b.a. 







- Po=normally closed actuators / Ps=normally open actuators 

- Mounting in vertical direction, actuator on top (max. angle from vertical 70°, with liquid cryogens use convection brake cat. no. 930108) 

- Cryogenic length h according order specification, indicated length is a recommended standard for LHe service 

- To reduce of heat load, cryogenic length "h" could be elongated or add thermal contact according to catalogue no. 930435 

- For further reduce of heat load, a modified inset as compound design in ss and GFK tube is available on request 

- For valves in sub-atmosphere pressure conditons a He-guard space seal system to outside i.e. full double seal is available on request 

- Valves with a short bellows section to the vacuum envelope on request 

- For valves with body shape in globe pattern, Y-slanted or shifted inlet-outlet (i. e.Z-pattern) see catalogue no. 911003 

*1) Bigger actuators for higher shut-off pressure on request / *2) Smaller actuators for lower shut-off pressure on request 

All dimensions in "mm", subject to change without further notice! 

930219MasseP-TEV-MA.xls/Dimensions WEKA Drawing no. 930219 pages 6/8 Jan. 2000/FHo

Standard - WEKA AG

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