| 摘要 |
958,129. Valves. RHEINISCHES METALLWERK G.m.b.H. Dec. 2, 1960 [Dec. 5, 1959], No. 41640/60. Heading F2V. A rotary conical plug cock comprises a plug 13 having a passage 14 and rotatable between open and closed positions, the plug being displaceable in an axial direction and provided with a corrugated flexible tube 31 for sealing the stem 15. In order to press the plug into contact with its seat the upper end of the latter is formed with a cam surface which co-operates with a complementary cam surface 27 formed on a cover plate 28 clamped in the valve housing 11 by a screwed bonnet member 16. The lower end of the plug is also formed with helical cam surfaces 23, 24 which co-operate with complementary cam surfaces 21, 22 formed on the housing so that upon rotation of the plug to the open position the plug is lifted out of contact with its seat. To ensure satisfactory sealing, the conical surface of the plug is covered with a rubber sleeve 17 which is integrally formed with a corrugated bellows portion 31, the latter portion being clamped, via a flange 32, to the valve housing; the rubber covering on the plug may be replaced by a coating of rubber in the bore. The bellows portion is shaped with the corrugated portion 44, Fig. 10, tapering inwards towards the valve stem 15 in order to permit the axial movement of the plug. In a modification, the corrugated portion may taper inwardly from the middle towards both ends. A stop 30 on the upper end of the plug co-operates with a recess in the plate 28 in order to limit the rotation of the plug. |
