The Standard for Fast Reliable UHV and XHV System Protection

The main requirement of a fast closing shutter is to react fast and reliable in case of air inrush. A loss of an UHV or XHV environment through air inrush, especially in large volumes like accelerators or storage rings can lead to significant problems in terms of contamination, component damage and the effort to be taken to restore the required vacuum level.

The 77.3 UHV Fast Closing Shutter protects vacuum levels with a fast closing reaction in case of a pressure rise. With below 10 milliseconds (depending on the shutter diameter), the series closes vacuum lines in an outstanding fast speed. Closing the shutter reduces the air inrush almost immediately to mbar l/s level. This leaves time to activate the all-metal valves used for hermetic sealing of the residual leakage. As any millisecond counts in preventing the degree of damage, the 77.3 set the benchmark for protection.  

The 77.3 is designed as slot shutter valve (DN 40 - 160), while the DN 40 version is designed with circular opening instead of slot opening. The series is pneumatically actuated. The standard bake out temperature is max. 300°C for valve body and max. 50°C for the actuator. The bonnet is metal sealed and a welded metal bellows seals the feedthrough.

The fast closing shutters are controlled by a separate controller. The controller ensures the fast closing time by regularly checking the readiness status of the system, the sensor(s) and the connection to them. The controller is modular and can be configured for different shutter/sensor arrangements. In the event of a detected air inrush, the controller activates, in addition to the fast closing shutters, an all-metal valve that is hermetically sealing under UHV or XHV conditions. The status of the fast closing shutter is also provided by the controller for remote output. Vice versa, the shutter can be remotely controlled via interfaces on the controller.

Already proven in leading accelerators and storage ring facilities under various process conditions, the 77.3 UHV Fast Closing Shutter series has become the standard for reliable UHV and XHV system protection.

Slot shutter DN 40 (closed)
Slot shutter DN 63 – 160 (closed)

The 77.3 UHV Fast Closing Shutter body material is stainless steel. The standard flange connector is CF-F. Customer specific flanges are an option as well as specific slot dimensions.

The series has a radiation resistance of 108 Gy for the valve body and 104 Gy for the pneumatic actuator.

Standard time until first service is 2000 cycles for the flap shutter and 5000 cycles for the slot shutter, which means the valve series is for its purpose practically maintenance free. 77.3 UHV Fast Closing Shutters are generally used in conjunction with all-metal valves.

77.3 UHV Fast Closing Shutter


  • UHV and XHV compatible
  • Fast high protection closing mechanism 
  • Highly reliable


  • Proven technology
  • Practically maintenance free
  • Low cost of ownership
Technical data
Sizes   DN 40 (1½"), DN 63 (2½"), DN 100 (4"),
DN 160 (6")
Actuator Pneumatic Double acting
Body Material   Stainless Steel
Feedthrough   Bellows
Standard Flanges   CF-F
Leak Rate Valve Body < 1 × 10-10 mbar ls-1
  Valve Seat < 30 mbar ls-1
Pressure Range   UHV to 1.2 bar (abs)
Cycles until first Service Slot Shutter
Flap Shutter
Bake-Out Temperature Valve Body ≤ 300°C
  Actuator ≤ 50 °C
Radiation Restistance Valve Body
Pneumatic Actuator
108 Gy
104 Gy
Material Valve Body AISI 316L (1.4435, 1.4404)
  Mechanism AISI 304 (1.4301) (DN 40) 
AISI 316L (1.4435) (DN 63 – 160)
  Gate / Plate AISI 316L (1.4404), silver-plated (Slot shutter)
Titanium (Flap shutter)
  Bellows AISI 633 (AM 350) (Slot shutter)
AISI 316L (1.4404) (Flap shutter)
Seal Bonnet Metal
Mounting Position   Seat Side (marked)
in opposite direction of the air inrush


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