| 摘要 |
<p>1,227,465. Pilot-operated gas valve. ROBERTSHAW CONTROLS CO. Oct. 11, 1968 [Oct.13, 1967], No.48388/68. Heading G3P. With temperature responsive valve 42 open, gas from inlet 18 can pass via 40-46 to chamber 48 to depress diaphragm 70 to unseat valve 66 thereby opening by-pass line 56, 58, 72, 54. The pressure in the by-pass line is controlled at a preset level determined by pressure regulator 74-86 and is communicated at 60 to chamber 34 to allow opening of main valve 26. Upon closure of valve 42, the pressure in chamber 48 falls, due to escape of gas via 50, 52, 54, and valve 66 seats thereby causing the pressure in chamber 34 to approach inlet pressure and close valve 26. In the modification of Fig.2 (not shown), the temperature responsive valve (42) admits gas to chamber (114) when open to depress diaphragm (104) thereby subjecting the diaphragm (94) of pressure regulating valve (90) to a load via spring (100). Valve (90) then controls pressure in a by-pass line as above to position the main valve (26). Gas escapes from chamber (114) via (116, 118) when valve (42) closes thereby allowing spring (96) to close valve (90) to cause closure of valve (26).</p> |
