| 摘要 |
<p>1415568 Valves S K ASSERSEN 18 April 1973 [20 April 1972] 18796/73 Heading F2V [Also in Division B3] A valve 10 controlling the supply of compressed air to sandblasting equipment comprises valve pistons 16, 28 subject to a control pressure in common chamber 26, the heads 25, 31 of the respective pistons being of greater effective area than the opposite ends. The latter comprise respectively a frusto-conical head 17 co-operating with seat 23 to control flow of compressed air from inlet 3 to outlet 24 leading to the sandblasting equipment and a head abutting flexible diaphragm 33 to control venting of the equipment receiver to atmosphere via pipe 11 and ports 36. Chamber 26 is supplied with compressed air via passage 38 and setting screw 39 and is provided with a vent passage 40 leading to a manually operated three-way valve 41. The latter is normally set to communicate with a control bore running parallel to the main sandblasting hose and having at its end a valve normally held closed by the operator. When the operator releases the valve, chamber 26 is vented to atmosphere causing pistons 16, 28 to respectively close and open their associated valves. Valve 41 can be set to vent chamber 26 directly to atmosphere to cause an immediate process stop. Chamber 26 may be provided with a safety valve venting to atmosphere and may be supplied with control air from an alternative source.</p> |
