NEC vacuum valves are used for a variety of reasons. Our valves are ultra-high vacuum compatible and allow rapid and reliable closure.
Three types of valves are available:
Metering Valves: for critical metering of gases into vacuum from high pressure sources
Right Angle Valves: for roughout and pump isolation purposes
Straight Through Valves: for applications requiring clearance for particle or optical beam transmission
NEC valves employ a toggle mechanism that provides constant seal forces until an external adjustment is necessary. Whether actuated by hand, air or other remote method, the unique NEC toggle mechanism provides a sealing force independent of operator or facility variations. Longer seat life is the natural result.
The stainless steel valve is fully ambient pressure isolated, which is ideal for operation in environments that vary from high vacuum to high pressure.
The NEC metering valve regulates the flow of gas from vacuum tight shut-off rates exceeding 100atm-cc/hr. Input pressures can be as high as 2000 psi.
The valve mechanism consists of a slightly curved flexure strip, which axially loads a soft gold seat into a stainless steel knife edge. As a transverse load is applied to the strip, it tends to straighten, thereby applying a sealing force.
The sensitivity is controlled by the extent the flexure has been straightened upon contact with the knife edge. This extent is adjustable by means of a manual adjustment screw. The flow rate is controlled by a differential screw that provides the transverse load to the flexure strip.
Manual and remote controlled versions are available.
This ultra-high vacuum valve utilizes a short stroke toggle mechanism, which allows a single quick motion for closure. This is a distinct advantage over the standard screw type sealing mechanisms.
The sealing mechanism is a replaceable aluminum disc that is pressed against a stainless steel knife edge by the toggle mechanism, which assures repeatable vacuum tight seals to better than 10-9 atm-cc/sec. In the case of the remote version, the toggle mechanism is actuated by a pneumatic cylinder that closes the valve to a vacuum tight condition in about 0.2 seconds.
The NEC straight through valve is ideal for applications that require ultra-high vacuum compatibility and rapid reliable closure. The fast acting model is ideal for applications that require an emergency closure in case of catastrophic failure of an ultra-high vacuum system.
These valves utilize the same short stroke toggle mechanism as the right angle valves.
There are three models of straight through valves available. Below is a brief description of each model.
Manual Straight Through Valve
Pneumatic Straight Through Valve
Fast Acting Straight Through Valve