| 摘要 |
1334290 Clearing blocked pipes G TASH 22 Dec 1971 [21 Jan 1971 16 June 1971] 59607/71 Heading F2N A device for clearing a blocked pipe 22 (Fig 2), comprises a tube 11 (Fig. 1), of resileint material, a valve assembly 13 which normally either closes one end of the tube 11 or leaves open only a small part of the cross-sectional area of the tube at this end, and a fitting 12 for connection with a source of high pressure water. In use (Fig. 2), the tube 11 is expanded by the high pressure water into sealing engagement with the pipe 22, thereby isolating a section of the pipe between the blockage and the device, and then the valve 13 opens to admit high pressure water to the isolated pipe section to clear the blockage. When the valve 13 shown is closed (Fig. 1), a small flow passage via orifice 20 and hollow section 15 remains open. The valve opens when the tube 11 expands to clear valve head 14 and permit flow via space 21, apertures 19 and hollow section 15. In a first modification, Fig. 3 (not shown), the valve comprises a disc, permanently engaged around its periphery by the tube 11 and formed with a central aperture, normally closed by a spring urged ball, the latter being moved away from the aperture against the spring by pressure within the tube, when this pressure exceeds a certain value. In a second modification, Fig. 4 (not shown), the valve comprises an apertured disc, normally engaged around its periphery by the tube wall, but permitting flow between its periphery and the tube wall when the latter is expanded by water pressure. The device may include a length of wire, nylon or cotton extending through the tube 11 and secured to the ends of the tube to limit longitudinal extension of the tube. |
