Ultra-high Vacuum Type-L Polyimide Valve

This is a type-L valve that can be used in ultra-high vacuum range of up to 10-8Pa. The vacuum seal is made of polyimide resin, which is highly heat tolerant and low on gas emission. Suitable as a valve for ultra high-vacuum equipment with bake-out temperature of 150℃ or greater.



  1. High heat tolerance
    Either open or closed, the polyimide seal endures repeated baking from room temperature to maximum 300℃.
  2. Seal material with low gas emission
    Since the gas emission of polyimide resin is lower than fluoro rubber (Viton), it can easily achieve ultra-high vacuum of about 10-8Pa. (See Dimension Diagram)
  3. Small tightening torque
    Polyimide seals do not require tightening torque as much as metal seals. Ultra-High Vacuum Type-L All-metal Valve


Ultra-high Vacuum Type-L Polyimide Valve(Type:951-7145 / 951-7120)

Type 951-7145 951-7120
Operating vacuum range Atmospheric to 10-8Pa
Allowable heating
temperature*1, 2
300℃ 300℃
Seal material
Polymide resin Polymide resin*4
Recommended sealing force
(sample tightening torque*5)
1225 to 1921N (2 to 3.4N·m) 3920 to 4900N (4.9 to 5.9N·m)
Maximum sealing force
(sample tightening torque*5)
2626N (5.9N·m) 7840N (14.7N·m)
Operation Manual If baked several times,
use adjustable pin face wrench
Conductance 1L/sec 30L/sec
Leak*3 6.7×10-11Pa·m3/sec or less 6.7×10-11Pa·m3/sec or less
Used material Main unit:SUS-304
Handle:AL alloy (black alumite)
Main unit:SUS-304
Handle:AL alloy (black alumite)
Connection flange φ34ICF flange φ70ICF flange
Weight 0.41kg 1.6kg
Attachments - Adjustable pin face wrench,
hexagonal wrench

*1. All values are based on a valve with its interior replaced with vacuum or inert gas such as Ar gas.

*2. 260℃ if heated continuously.

*3. Gas permeation of the polyimide resin is out of specification.

*4. Please consult with us about upgrading the bonnet seal to a metal seal (SUS321 silver plated O-Ring).

*5. Tightening torque is a reference value, for baking increases the friction coefficient of the moving screw and changes the balance between the tightening torque and the tightening seal force.