Explosion-proof pressure relays are meant for electrical switching when pressure reaches the set values (activation setpoint) and switching back the contact group when pressure changes by the differential value.
- relays have one normally open and one normally closed contact. Contacts provide switching of active and inductive loads with (1 ... 100) mA current at (20 ... 30) V voltage. The number of activations is not more than 105 under these loads;
- mass-produced, have "1ExdIIBT4" marking of explosion protection, conform to GOST 12.2.020-76, GOST 22782.0-81, GOST 22782.6-81;
- According to the degree of protection against dust and water - according to GOST 14254-80.
|Range of activation setpoints||MPa||(0-0,0025...0-0,01)...(3,0-6,0)|
|Operating temperature range||°C||-50...+70|
Relays have two versions and modifications, different in the range of activation setpoints (see. Table below).
Version 1: : relay is actuated (closure of contact 1-2) when the pressure increases up to the opening pressure [Pact]. Relay is armed (closure of contacts 1-3) when the pressure goes down to value Rarm (Ract - D), where D is differential. Differential is the absolute difference between the actuation pressure [Pact] and the arming pressure [Parm]. The initial state for all relay versions is the state, when the pressure in the working volume of relays is equal to the atmospheric one.
Version 2: relay is actuated (closure of contact 1-3) when the pressure goes down to the actuation pressure [Pact] after preceding pressure increase up to the arming pressure [Parm] (closure of contact 1-2) greater than [Pact] by the value of differential D. Differential is the difference between the arming pressure [Parm] and the actuation pressure [Pact].