| 摘要 |
<p>1,219,726. Valves. M. H. GROVE, and J. M. EMERY, [trading as M. & J. DEVELOPMENT CO.]. 5 May, 1969 [7 May, 1968], No. 22786/69. Heading F2V. Leakage of fluid past the seals in a gate valve is detected by venting the upper part of the valve chamber for a predetermined time after the valve has closed, and then detecting any rise in pressure in the chamber. Pressureresponsive switch 22 and solenoid operated valve 21 communicate with the chamber through pipe 24 which extends through chamber wall 26. Timer 23 has a heated bi-metallic strip element 32 which operates change-over switch 34, and a switch 36 is closed automatically when the gate valve closes. In operation, closure of contacts 36 initially establishes circuits through element 32 and the solenoid of valve 21 which is thereby opened. After a time determined by element 32, switch 34 de-energises the solenoid and establishes a supply through line 45 to the contacts of switch 22 so that in the event of a pressure build up in the chamber, an indicator lamp 57 is energized through line 47 and circuit blocks 56, 52. A switch 61 shunted across switch 36 enables the apparatus to be cycled without moving the gate. Sixteen valves are connected to a common indicator lamp 57 which, with switch 54 closed, lights up for a fault in any of the valves. By opening switch 54 and operating stepping switch 58 the particular valve at fault can be identified. The gate valves are operated by pneumatic cylinders 11 controlled through relay valves 66, 74 and 74. Specification 1,188,153 is referred to.</p> |
