Test device for pressure and/or temperature limiters in steam and hot-water boilers

摘要

The test device for pressure and/or temperature limiters is used in steam or hot-water boilers. It possesses a switch 4 which is located in a safety circuit for the fuel supply and for the actuation of which a trip relay 3 is provided. The control circuit of the trip relay 3 can be influenced by the pressure and/or temperature to be monitored by means of a measuring sensor 7 which detects these state variables. The trip relay 3 has two control circuits 5, 6, the measuring sensor 7 being provided in one control circuit 5 and the other control circuit 6 having an electric resistance 8, the size or value of which corresponds to the trip value in the trip relay 3. The two control circuits 5, 6 can be switched alternately to the trip relay 3. The switch 9 serving for alternately cutting in the control circuits 5, 6 possesses wiper contacts 10, 11, so that, when the switch 9 is actuated, in each case one control circuit 5 or 6, only opens when the other control circuit 6 or 5, respectively, is closed. IMAGE