The NEC coaxial pressure sensor and trigger controller are used with the fast acting valve and sensor trigger controller for reliable protection against catastrophic vacuum failure.
The NEC coaxial pressure sensor, which consists of a fine wire along the axis of a small grounded cylinder, detects a pressure rise, to a selectable level of 10-4 to10-2 Torr. The wire stays at a few kilovolts potential. As the pressure rises above the selected limit, a discharge occurs and a large current flows between the wire and the cylinder. This signal allows actuation of the trigger solenoid at the fast acting valve.
All materials in the coaxial pressure sensor are ultra-high vacuum compatible. There are no organic compounds in the vacuum volume.
This circuit uses the current signal from the coaxial sensor to discharge a capacitor into the valve trigger solenoid. This in turn releases the trigger plate that normally holds the handle of the fast acting valve in the open (cocked) position. Closure time is less than 35 milliseconds after receiving the trigger signal.
The sensor controller panel indicates the status of the valve, fired or disabled, and power to the unit. There is a switch on the front panel that allows the manual firing and able or disable of firing mechanism. There is also a trigger pressure sensitivity adjustment.
The complete system – consisting of the fast acting valve, coaxial pressure sensor and the trigger controller – provides reliable protection against damage due to catastrophic vacuum failure.
If multiple valves need to be triggered simultaneously, an additional controller (valve trigger controller) can be added to the CPS system to trigger a secondary valve when the CPS system triggers the primary valve.
NEC designed the coaxial pressure sensor to interface with the NEC sensor trigger controller, Model PS4, to actuate the NEC fast acting valve.
| Triggering Pressure: | Adjustable from 1 x 10-4 Torr to 1 x 10-2 Torr (measured for a gradual pressure rise) |
| Sensor Mount: | Standard NEC 3.5” O.D. NEC flange.(other flanges available on request) |
| Sensor Controller: | Input: 115V, 50-60Hz, 0.5A |
| Output: 4.3kV peak, 200mA |
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