P/00/0011 Regulation 3.2 AUSTRALIA Patents Act 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT ORIGINAL Name of Applicant: APEX VALVES LIMITED Actual Inventors: DAVID GORDON ARTHUR CRICHTON Address for service in Australia: Newnham & Co Level 1, 425-429 Pacific Highway, Crows Nest PO Box 1325, Crows Nest New South Wales 2065, Australia Ph: 0064-27-231 6702 Fax: 0064-9-414 6012 Invention Title: IMPROVED LIQUID CONTROL VALVE The following statement is a full description of this invention, including the best method of performing it known to us: 11- 2 This invention relates to liquid control valves and in particular to a flow enhancement element therefor. A problem with liquid control valves, at least with water "ON/OFF" control valves, is balancing the requirements of a robust, positive and ready closing and opening mechanism 5 and action against achieving an appropriate flow rate through the valve. A related problem can be "water-hammer" which can arise as a consequence of either not "balancing" the factors mentioned aforesaid or by otherwise caused abrupt changes in the flow rate or flow path through a valve. An object of this invention is to provide a flow enhancement element that can be included in such valves and which it is envisaged will at least partly alleviate the 10 aforesaid problems. A further object is to provide the public with a useful choice. According to a first embodiment of this invention there is provided a liquid control valve wherein a dynamic closure member includes an annular shaped seal adapted to seat and unseat against and from an annular valve seat to respectively close and open the valve and wherein a flow path through the valve includes an outlet port formed by the interior space of 15 the valve seat and a conjoining upstream section passing about the closure member seal, characterised in that an annular flow enhancing element is provided in juxtaposition to the valve seat on the upstream side thereof with the bore of the flow enhancing element being spaced radially outward of the closure member seal and including an annular flow path cross-sectional reducing section. 20 According to a second embodiment of this invention there is provided a liquid control valve as described in the preceding paragraph wherein the valve seat is in the form of a washer and the flow enhancing element is integrally formed therewith.
3 According to a third embodiment of this invention there is provided a liquid control valve as described in either of the two immediately preceding paragraphs wherein the cross-sectional reducing section of the flow enhancing element is formed in two spaced apart portions, one portion being at the upstream commencement of the bore and the second portion at the down 5 steam termination of the bore. According to a fourth embodiment of this invention there is provided a liquid control valve as described in any one of the three immediately preceding paragraphs wherein at least an upstream portion of the cross-sectional reducing section of the flow enhancing element is frustro-conically shaped. 10 According to a fifth embodiment of this invention there is provided a liquid control valve as described in any one of the four immediately preceding paragraphs wherein at least a downstream terminating portion of the cross-sectional reducing section of the flow enhancing element is arcuately formed. According to a sixth embodiment of this invention there is provided a flow enhancing 15 element for a liquid control valve of a structure as described herein comprising an annular body having a bore of reducing cross-section formed in two spaced radially apart portions, one portion forming one end of the bore and the second portion the opposite end of the bore, the diameter of the end of the bore of minimum diameter being marginally larger than that of the bore of a washer of a valve in which the flow enhancing element is intended to be 20 mounted. In further describing the invention reference is made to the accompanying drawing (Fig 1) being a cross-sectional view of a float operated water control valve depicted in a closed 4 mode. In known manner an inner end 1A of a float arm 1 impinges downwardly on a dynamic closure member preferably in the form of an annular shaped reciprocally operative plunger 2. Plunger 2 operates in a reciprocal manner along the line of its longitudinal axis and includes a lowermost rim which forms a seal 3 which seals on an annular valve seat 5 preferably in the form of an annularly shaped washer 4 to close the valve. Lowering of the outer end of the arm 1 enables the plunger 2 to rise to open the valve. A flow path through the valve commences with an inlet 5 leading to an annular shaped cavity 6 within the valve and extending about the plunger 2. The cavity 6 conjoins with the central aperture or bore 4A of the washer 4 which forms an outlet port for the valve. 10 Characterising this invention is a flow enhancing element 7 which is preferably formed as a separate unit from the washer 4 but as will become apparent from the following description could be formed as an integral part thereof. The flow enhancing element 7 is of an annular shape similar to that of the washer 4 and is mounted in juxtaposition to the washer 4 on the upstream side thereof 15 More particularly, the wall of the bore 7A of the flow enhancing element 7 is preferably in two sections or 8A and 8B to form a flow path 8 therethrough of a commensurately two stage reducing cross-section. A first section 8A is formed at the start or upstream side of the bore 7A and the second portion 8B at the down-stream or terminating section of the bore 7A. The section of the bore 7A defined by wall section 8B is of a diameter marginally larger than that 20 of the washer this enabling the seal 3 of the plunger 2 to seat on the ledge of the washer 4 protruding inwardly thereof. Preferably the wall section 8B is convexly shaped to provide an a corresponding reducing in the cross-section of the bore 7B defined thereby. Preferably the upstream wall section 8a defines a section of the bore 7A of a substantially larger diameter than that of the downstream section and is of a reducing diameter. To that end wall 5 section 8A may be, as depicted frustro-conically shaped, or may be convexly or concavely shaped. The two sections 8A and 8B are spaced radially apart by an intermediate portion 8C. Preferably at its maximum and start the cross-section of the bore 7A defined by wall section 5 8A is commensurate to that of the section of the flow path about the plunger 2. To that end, the flow enhancing element 7 is preferably captivated within an annular recess 9 formed in the inner wall defining the lower end of the cavity 6 such that the reducing diameter surface of the reduced portion 8A is flush with the surface of the wall of the cavity 6.