Variable and fixed low pressure switches
The variable pressure switch PS 115 and the fixed low pressure switch PS 113 A indicate whether or not the pressure has reached atmospheric pressure level after venting.
In the PS 113 A the diaphragm pressure switch is set to a trigger of 6 mbar (4 Torr) below atmospheric pressure. The PS 113 A uses a EPDM diaphragm and is therefore n ot suited for applications in which the process gas contains large quantities of helium.
The PS 115 has FPM sealing and stainless steel construction, making it more suitable for corrosive environments. It is adjustable between 0.5 and 2000 mbar (0.4 and 1500 Torr).
Via a differential pressure adapter (optional) the PS 115 may be converted to operate as a differential pressure switch rather than an absolute sensor.
The adapter consists of a DN 16 ISO-KF flange with screw-in thread and a sealing arrangement, and it is screwed into the PS 115 instead of the adjustment valve. The operating range extends to 2000 mbar (1500 Torr). Brief over-loading to 3000 mbar (2250 Torr) is permissible without impairing switching accuracy. In this operating range differential values of +5 to -20 mbar (+3.75 to -15 Torr) can be adjusted via the set screw.