| 摘要 |
<p>A ball check valve which may be used for vertical or horizontal flow has a body 1 comprising a flow path 8, a turnout path 6, an inlet 2 and an outlet 3. Contained within the body 1 is a ball 5 which engages a seat 4 at the inlet side when the valve is closed. The seat 4 is inclined (see dotted lines) towards the inlet 2 when the valve is positioned with the flow path 8 horizontal. There is a guide with a part 9 to guide the ball 5 between the seated position and a position in the turnout path 6 and a part 10 to infallibly seal the ball on the seat 4. The ball 5 may consist of a metallic sphere 5a coated with a rubber or synthetic resin. In a further aspect of the invention, one or two passages 16 may be provided between the inlet 2 and the seat 4 on a flange part used to connect the body to a pipe, the passage being connectable to an on/off air control valve. In a further aspect still, the seat 4 and guide 9 may be arranged so as to prevent extraneous matter from lodging the valve open by providing a gap (35, figure 14). The valve may be included in part of a pumping system (figures 19-21), closing on stopping of the pump to prevent reverse flow. Two pumps and two valves may be installed in a parallel fashion and be operated individually in case of breakdown of one.</p> |
