GB436073A - Improvements relating to valves - Google Patents

Abstract

436,073. Valves; lubricating. MERCO NORDSTROM VALVE CO., 400, North Lexington Avenue, Pittsburg, U.S.A. Jan. 1, 1934, No. 34. Convention date, Sept. 27, 1933. [Class 135] [See also Group XXXIV] A plug valve includes means for yieldingly holding the plug in its seat, an operating stem connected to the plug, co-operating sealing surfaces on the stem and casing, means for supplying lubricant under pressure to a chamber into which the inner end of the stem extends, and a recess to contain plastic material under pressure and surrounding a threaded portion of the stem to prevent leakage between the sealing surfaces. As shown, the sealing surfaces consist of screwed threads 26, 27, on the stem 23, and casing 10. The casing 10 has a lubricant chamber 28 and pressure is applied to the lubricant therein by screwing plugs 32 into passages connected to the chamber 28. The valve plug 13 has a lost-motion tongue-and-groove connection with the stem 23 and the latter is rotated by a worm gear or by a wrench. The casing 10 has a lubricant chamber 16 connected to a bore 42 in the stem 23 and to short longitudinal grooves 46 in the seating surface 12. The plug 13 has pairs of longitudinal grooves 47, 471, connected by circular grooves 48, 481, the grooves 47, 47<1> communicating with the grooves 46 only in the open and closed positions of the valve. The valve plug is pressed to its seat by a resilient cover 18 acting through an adjusting screw 53, a diaphragm 55 and a ball 57. A ball valve is inserted in the bore 42. To lift the valve from its seat prior to turning it a plug 44 in the bore 42 is rotated to put the lubricant in the chamber 16 under pressure. This pressure is increased by the axial movement of the stem 23 during turning of the plug. In a modification, the plug has two sets of grooves 70, 71, Fig. 5, the grooves 70 being open to the chamber 16. In the open and closed position of the valve each set 70, 71, registers with short longitudinal grooves 73, 74, connected by a helical groove 72, the grooves 72, 73, 74 being formed in the seating surface of the casing. To prevent accumulation of pressure the space 17 at the large end of the valve is connected to a groove 70 by an attenuated spiral groove 75. Specification 270,246, [Class 135], is referred to.