GB405385A - Improvements in air release and ventilating valves for water mains and the like - Google Patents

Abstract

405,385. Fluid-actuated valves. GLENFIELD & KENNEDY, Ltd., PRICE, O. A., and KENYON, J. M., Kilmarnock, Ayrshire. Sept. 17, 1932, No. 25874. [Class 135.] In a valve for releasing air from water mains &c., a valve member in the form of a float 4 located in a valve chamber to which is led an inlet branch 3 from a water main or the like controls an outlet orifice having a cross-sectional area of the order of that of the inlet branch and has a lift of the order of the valve diameter, the valve member functioning in effect as an "adherent disc," i.e. a disc maintained by suction over an orifice in a plate through which fluid passes, with respect to a stream of fluid of low density, say air, impinging upon it but being repelled to the closed position by a stream of denser fluid, say water. The valve member is preferably in the form of a ball float 4 in a cone socket 5 at the top of the inlet branch 3 as shown in Fig. 2 but valve members of cylindrical, conical, ovoid, or other form which need guiding means may be used. By experiment it has been found that for a convenient cone angle and suitable ball stops 9, a ball is just poised on an air stream if its diameter is 1“ times the stream diameter, i.e. the diameter of the pipe 3, and is just poised on a water stream if its diameter is 2“ times the stream diameter. Balls of respectively less diameter are repelled by streams of the respective fluids and a ball whose diameter lies between these limits, say 1¥ times the stream diameter, is held by air but repelled by water. Fig. 8 shows a practical form in which the stops 9 are omitted so that although air may escape during pipefilling, air cannot enter the main when the ball 4 falls from its resilient seat 18<1> in the apertured cover 18 of the valve chamber. The height of the stops 9 has been found to influence the suction effect and in general to decrease the effect as it increases. For an open-mouthed cone, the stops are conveniently 1/5 to 1/8 the stream diameter but for a valve chamber with an orificed cover, their height may be 2/5 of the stream diameter. Instead of stops, an apertured cup spaced from the wall of the valve chamber by webs may be used. A valve according to the invention may be combined with other forms of valve. Thus a known form of high pressure valve comprising a ball float 13 may be located in chamber offset from but communicating with the chamber of the valve 4, this valve controlling a small outlet orifice 19 in the valve cover. A screwdown isolating valve 14 may be positioned between the inlet branch 3 and the main, or, as shown in Fig. 12, a ball valve 4 according to the invention may be combined with an isolating valve 14 and a high pressure valve 13. In the forms incorporating an isolating valve, a baffle 15 prevents undue distortion of the impinging stream. In another form, a high-pressure valve such as 13 and a low-pressure valve such as 4 is combined with a third ball float which controls an orifice of intermediate size which allows escape of large volumes of air at low pressure after the low pressure valve has closed. The inlet pipe 3 may, in any of the forms, be bell-mouthed to steady the fluid stream before it reaches the ball 4. The invention is applicable to fluids other than air and water.