| 摘要 |
A vapour containment valve cartridge 7 comprises a cartridge housing 12 for mounting within a valve housing and having an inlet, an outlet and a valve surface arranged between the inlet and the outlet and forming a portion of a generally spherical surface 18. A valve body 28 is received within the cartridge housing 12 and has an enlargement 31 forming part of a generally spherical surface of generally equal curvature to the generally spherical surface 18 on the cartridge housing 12. A resilient O-ring seal 34 is accommodated in a groove 36 on enlargement 31 such that the weight of the valve body 28 causes sealing between the two generally spherical surfaces. As a result, vapour in the valve housing 12 below a threshold pressure is prevented from passing from the inlet to the outlet, and vapour above the threshold passes from the inlet to the outlet. |
