Patent GB-771524-A (GB)
Title: Improvements in or relating to gas-heated appliances
IPC: F23N5/10
Filed: 1955-09-09
Abstract: 771,524. Electric igniters. BOSCH GES., R. Sept. 9, 1955 [Sept. 10, 1954], No. 25820/55. Addition to 770,485. Class 75(1) The gas heated appliance of the parent Specification is further provided with a safety valve adapted upon extinction of the pilot flame to cut off automatically the supply of gas to both the main arid pilot burners, and with an operating member associated with the safety valve and control valve and adapted to open the safety valve only when the control valve is closed. Preferably, this operating member when moved into the igniting position for igniting the pilot burner, first closes the control valve and then opens the safety valve. The interlocking means of the appliance described in the parent Specification may comprise a coupling between the said operating member and the igniter actuating member, which will be actuated when the operating member is displaced into the igniting position. The control valve may be adjustable by rotatable rod' axially displaceable to form the operating member. As shown a housing 114 contains a rotatable cock plug 113 open on its inner end face and located in a conical bore connected with the main burner 111, the plug when in the open position shown, having a transverse main bore 120 disposed opposite a bore 115 in the housing and an auxiliary bore 121 diametrically opposite arranged. to communicate with a groove. 222 on the periphery of the plug and supplies gas to a bore 119 in the housing which leads through supply line 118 to the pilot jet 117. The cock plug 113 has a neck 140 having two oppositely disposed axially directed grooves 141, 142 along which a transverse pin 135 on a tubular member 138 moves when the latter is depressed against the action of spring 132 and one end of the pin acting as a follower projects into a cranked control slot 139, Fig. 5, cut out of a tubular member 136 fixed to the housing 114, on longitudinal movement and rotation of the member 138 by the handle 137. In the initial position of the member 138, the plug closes both bores 115 and 119. The member 138 is firstly depressed as the pin 135 rides down the first vertical limb of slot 139 and the rod 130 is axially displaced in the plug to displace the valve plate 116 from its seat and allow gas to flow from the inlet I into the inner hollow space of the plug 113. As the rod 138 is then turned through a small angle with the pin 135 in the base of the U-portion B of slot 139, the groove 222 comes into communication with the bore 119 to feed gas to the pilot burner 117, the pin 135 locking the valve open, whilst the contact spring 160 is raised to open the short circuit across the primary coil of the igniter as in the parent Specification and allows actuation of the igniter by depression the bar 45, and ignition of the pilot burner 117 to heat the thermal element 125 which supplies sufficient current to the electromagnet 126 to return the armature 128 and the valve 116 secured thereto open, the member 138 being then rotated further until the pin 135 rides up the other limb of the U-slot 139 under the action of spring 132, whereupon continued rotation takes the pin 135 along the upper horizontal portion of the slot 139 during which movement the bores 115 and 120 are brought into communication. In a modification, Fig. 2, (not shown) the member 138 has a simple depressing movement during the initial stages of which it closes the main control valve before opening the safety valve, which latter ,valve is held by the electromagnetic latch 125, 126, 128 when the member 138 is returned to its unoperated position and the main valve opened. In either of the embodiments, Figs. 2 or 3 the member 138 may be mechanically coupled to the actuating bar 45 so that depression of the former to close the control valve operates the latter after an amount of lost motion therebetween to open the safety valve.