| 摘要 |
587,157. Valves. CRAIG, A., HENSHAW, H. L., and IMPERIAL CHEMICAL INDUSTRIES, Ltd. March 15, 1944, No. 4797. [Class 135] An isolation valve, particularly for use in plants working at reduced pressures or with noxious fluids, incudes a closure member having a rubber disc 9, Fig. 1, which coacts with a removable seat 5 held in position by an elastic ring 6 and a gland 7 which also secures the inlet pipe 8 in position, the outlet pipe 2 being similarly secured. Ingress of air between the removable valve spindle 10 and the body 1 is prevented by a bellows soldered at its inner end to the body and at its outer end to a cap nut spindle 11. Thus, the bellows can be' assembled and inspected with the spindle and the cover 13 removed. Operation of the valve is effected by the screw cap 14. Fig. 2 shows a combined isolation and control valve in which the bellows is secured at its inner end to a gland 19, secured to the body and sealed by a ring 18. Isolation is effected by the rubber disc 17, and flow controlled by a parabolic nose 16. In a modified form of isolation valve, the inlet pipe is secured to the body by a separate sealing ring and gland. By the provision of a range of valve spindles and matched seatings, the valve can be made to cover a wide range of flow rates.
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