GB271525A - - Google Patents

Abstract

271,525. Electric Heating Co., (Assignees of Ross, J. D.). May 24, 1926, [Convention date]. Controlling consuming devices - A switch, which may be fitted to a steam radiator fitted with a heating element 2, is subject to the combined control of a heat sensitive element and an element, sensitive to fluid pressure. The. switch includes a rotary member 7 co-operating with fixed contacts 4, 6 and mounted on a housing 42 containing a spring 41 fastened at its ends to the housing and a winding shaft 40 respectively. The shaft carries a ratchet wheel 50 engaging a pawl 51. A disc 44 having detents 45 is mounted on the housing and co-operates with an escapement lever 48 secured to a shaft 49. The heat sensitive member comprises a capsule 21 containing ether and secured to a partition 22. The capsule is connected to a lever 24 carrying a contact 12 co-operating with a contact 11 on an adjustable rod 27 to control the circuit of an electromagnet 14 the armature 35 of which is connected by a cranked lever 36 to the rocking shaft 49 of the escapement lever 48. Closure of the contacts 12, 11 energizes the magnet with consequent actuation of the escapement and closure of the switch. The pressure element comprises a bellows 61 subject to the steam pressure. A rack 63 fixed to the bellows engages a loose pinion 64 carrying a pawl 65 engaging a ratchet wheel 66 secured to the winding shaft 40. The bellows operates against a spring 67 and an adjustable spring 73. The rack 63 carries one of a pair of contacts 17, 16 in the magnet circuit and a projection 68 cooperating with a pin 70 on the escapement lever 48. Expansion of the bellows, breaks the magnet circuit, winds the spring 41 and finally rocks the escapement to open the switch. Additional thermal control may be obtained by means of a lever 75 pivoted to the partition 22 and fixed at one end to the lever 24 and engaging a pivoted cam 77 at the other end. When the capsule 21 has expanded sufficiently the lever 75 operates the cam to trip the escapement lever through the pin 70 and thus open the switch.