| 摘要 |
<p>1506121 Valves M H GROVE and J M E GROVE [trading as M & J DEVELOPMENT CO] 29 Jan 1976 [12 Feb 1975] 03541/76 Heading F2V Flow-control apparatus, e.g. for fluid distribution systems incorporating flow-meter testing circuits, comprises a hollow body 10, Fig. 1, having an inlet 14 and a pair of outlets 16, 17. Moreover, the body contains an axially adjustable tube 18 and is provided with sealing assemblies 13a, 13b, 13c, co-operable with cylindrical surfaces provided at sections 43a, 43b, 43c, 43d, 43e of the tube. The tube communicates with the inlet 14 and is provided with porting 26, 27 such that when it is in the position shown, the inlet and outlets are isolated from one another. In a second position of the tube a flow path is established from the inlet 14 through the porting 26, 27 to the outlet 16 and, in a third position, a similar flow path is established from the inlet 14 to the outlet 17. The tube is adjusted via a rod 19 by manual, electric, hydraulic or pneumatic means. Each sealing assembly comprises a pair of resilient sealing rings 38, Fig. 5, having surfaces 47 co-operable with larger-diameter sections 43 of the tube. The space defined between each section 43 and rings 38 is communicated through a passage 51 with a pressure indicator 54 and with a pressure switch 56 for operating signal lamps 59, 60, whereby poor sealing can be detected. In an alternative embodiment, Fig. 6 (not shown), the tube is formed with an annular recess instead of the larger-diameter sections 43 and the rings 38 co-operate with the tube on opposite sides of the recess. In another embodiment, Fig. 7 (not shown), the tube includes the larger-diameter sections 43 but the rings 38 are each replaced by a ring (76, 77) of substantially cup-shaped form in cross-section and having an annular spring (84) associated therewith.</p> |
