GB1297335A - - Google Patents

Abstract

1297335 Valves S A LEBLANC 28 May 1971 [23 Oct 1970] 17837/71 Heading F2V [Also in Division F4] Supplying gas to a burner at one of two possible output rates, is effected by an electromagnetically actuable compound valve having a single valve member 2 and a relatively larger double valve member 4, 5, the former controlling a low output passage 10, 12, 13, 25, 11, and the latter controlling a high output passage 10, 11. The single and double valve members are interconnected, with lost-motion, by a rod 14 extending from the magnet core 16. In use, closing of a switch 22 results in the core moving over only part of its possible stroke. In consequence, only the single valve member 2 is unseated. Closing of a further switch 23 results in the core moving to the end of its stroke as determined by the engagement of valve member 2 and valve wall 26. During this latter movement, part 5 of the double valve member 4, 5 is unseated first thereby allowing an equalization of pressure across valve part 4. Subsequently, a projection 8 on valve part 5 unseats part 4 with a tilting action. The truncated and flanged shape of the core 16 ensures that it attains one of two positions in dependance upon the voltage applied to the winding 71. An adjustable throttle valve 27 is disposed in the low output passage. In a modification, Fig. 2, not shown, the core 16 may be disposed within a winding which consists of two independently energizable coils (17a, 17b).