Reliable High-Speed Protection

The main requirement of a modern shut-off valve is its reliable and fast acting emergency isolation on any backflow event. The 25.7 is designed to provide a sensitive, high-speed isolation function that reliably prevents the risk of backflow into a process chamber or pipe system.

The 25.7 HV Quick Shut-Off Valve is flow controlled. The direct operating design without any subsystem (sensor and actuator) provides high-speed isolation with low complexity and low failure risk. With less than 10 milliseconds from the initial backflow impulse to full isolation the 25.7 leads its class.

As a safety solution, a shut-off valve should ideally add no conductance barrier to the system. The 25.7’s special flow-optimized design sets the standard in this regard, delivering a perfect balance between high conductance and fast isolation.

When used in processes with by-products in the gas stream, e.g. foreline applications, any accumulation of contamination on a quick shut-off valve reduces conductance and can negatively influence its isolation capabilities. This process related challenge is adressed by a special surface coating which minimizes accumulation for most by-products significantly. An additional heating option is available to avoid process gas condensation at the valve surface.    


emergency closure in case of backflow


The 25.7 HV Quick Shut-Off Valve is available in sizes from DN 50 - 160mm (2“ - 6”). The valve body is made of stainless steel. The standard flange is ISO-K for DN63 to DN160 (2½ “ - 6”) and ISO-KF for DN50 (2“). 

For applications with very aggressive process gases, FFKM seals are available.

Key features of the 25.7 HV Quick Shut-Off Valve


  • Flow-controlled movement
  • Outstandingly fast reaction time
  • Optimized conductance
  • Special surface coating to minimize by-product contamination


  • High level of protection
  • Extended lifetime
  • Easy installation
  • Low cost of ownership
Technical data
Sizes   DN 100 (4"), DN 160 (6")
Body Material   Stainless Steel
Standard Flanges   ISO-K
Leak Rate Valve Body
Valve Seat
< 1 × 10-9 mbar ls-1
< 1 × 10-6 mbar ls-1
Pressure Range   Vacuum to 1.2 bar (abs)
Differential Pressure On the Gate ≤ 1 bar
Conductance (laminar flow) DN 100
DN 160

6000 ls-1
20000 ls-1

Cycles until first Service   recommended after each backflow event
or with regular maintenance cycles
Temperature Valve Body ≤ 200 °C
Heating and Cooling Rate   ≤ 50 °C h-1
Material Valve Body
AISI 304 (1.4301)
AISI 304 (1.4301)
Seal Bonnet
Mounting Position   Fore line installation vertical only
gate facing chamber
Trigger Pressure ΔP at the Gate ≥ 5 mbar
Closing Time Gate Move Time
DN 100
DN 160

≤ 10 ms
≤ 15 ms

DN 100
DN 160

3.7 kg / 8.16 lbs
6.3 kg / 13.9 lbs


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