| 摘要 |
995,456. Valves. McEVOY CO. Aug. 7, 1962 [Sept. 26, 1961], No. 30219/62. Heading F2V. A gate valve comprises a body 11, Fig. 1, having flow passages 12, 13 therethrough, a chamber 14 within the body intermediate the flow passages, movable closure means 35 in the chamber, a sealant reservoir 21 in the body, seat means 30, and resilient means 28 biasing the seat means against the closure means, each seat means having a groove 71 exposed against the body and connected by a part 32 to a groove 31 exposed against the closure means. In the preferred embodiment each port 32 communicates through a port 23 with a separate sealant reservoir 21 or 22 fitted with a piston 80 subjected to the pressure in the valve chamber in order to pressurize the sealant. 0-ring seals 74 are provided at either side of the groove 71 and a port 36 in the closure member 35 registers with the seats when the valve is opened by a manually-operated screwed spindle 48. The closure member is detachably mounted on pins 43 on a connector 44 welded to the spindle so that it may be inverted to reverse the opening direction of the valve. A lubricant fitting 70 for a thrust bearing 57, 58, 59 and a fitting 71 to permit plastic or other packing material to be injected between rings 55 are provided in addition to fittings 75, only one being shown, and ports 76 for injecting sealant into the reservoirs. A check valve 82 permits grease to be injected into the valve chamber and may be unscrewed from the body to permit the chamber to be drained. In a modified construction, the closure means is mounted in guides and has a T-slot for loose engagement with the spindle which is restrained from rotation by flats in engagement with parallel pins having co-operating flat faces. The seat means are mounted in recesses in the flow passages and are assembled through the bonnet opening. To provide " upstream " instead of " downstream " sealing, each reservoir is closed by a plug 193, Fig. 6, and is pressurized through a line 191 from the corresponding flow passage. In further modifications each seat means has two parts 204, 205. Fig. 7, the inner part 204 being separately spring-loaded, as shown, or press-fitted into the body, a single seat means having two parts of different diameters is used, and a ring of elastomeric material is fitted in the groove facing the closure means. The 0-ring seals 71, 72 may be replaced by piston ring seals for high temperature applications. Specifications 995,457 and 995,458 are referred to. |
