AUSTRALIA Patents Act 1990 COMPLETE SPECIFICATION Invention title: "Liner for Gate Valve" Applicant: Stuart John Julien Associated provisional applications: The following statement is a full description of the invention, including the best method of performing it known to me: 2 "Liner for Gate Valve" 5 Field of the Invention The present invention relates to a liner for a gate valve. Background to the Invention Gate valves comprising a valve body and a slidable gate are generally 10 provided with a lining in order to seal between the gate and the valve body. In some known gate valves, the valve body is provided as a single unit having the lining bonded to the internal surfaces. In such an arrangement, wear of the liner requires replacement of the entire unit. 15 Gate valves provided in two halves have also been used, in which the liner is a separate unit that is held between the two halves of the valve body. Such an arrangement allows replacement of the liner when it becomes worn. The present invention relates to such a replaceable gate valve liner having 20 improved features aimed at reducing the likelihood of a build-up of material in and around the liner that would reduce the efficiency with which the gate valve operates. Summary of the Invention 25 According to a first aspect of the present invention there is provided a gate valve liner comprising: a chest portion; and a ring portion adjacent a first side of the chest portion, the ring portion comprising a cylindrical wall, an inner surface of which defines an opening 30 alignable with a bore in a gate valve; wherein an inner surface of the cylindrical wall includes a groove for receiving a rounded end of a gate and the depth of the groove decreases towards a point on a second side of the ring portion opposite the chest portion.
3 In one embodiment, the cylindrical wall includes an aperture adjacent the first side thereof to receive the gate such that the gate can pass through the chest portion, through the aperture in the cylindrical wall and across the opening. 5 Preferably, the depth of the groove decreases to zero adjacent the point on the inner surface opposite the chest portion. In a preferred embodiment, the depth of the groove increases as the groove 10 extends away from the second side of the ring portion in either direction such that the internal surface of the groove is complementary in shape to the rounded end of the gate. Preferably the rounded end is arcuate and the groove increases in depth such 15 that the distance between internal surfaces of the groove on opposed transverse sides of the rim portion is equal to the width of the gate. Preferably the chest portion includes first and second opposed side walls and one or more ridges are provided on inner surfaces of the first and second side 20 walls such that each of the ridges comprises a first side portion and a second side portion meeting adjacent a centre of the side wall at a vertex. Preferably, the first and second portions of each ridge are linear such that the ridges are generally V-shaped. 25 In a preferred embodiment, there are provided first and second ridges, the vertex of the first ridge being located adjacent the opening and the vertex of the second ridge being offset from the vertex of the first ridge towards a second end of the chest portion. 30 A further ridge is preferably provided on each side wall comprising a linear ridge extending across the inner surface in a direction transverse to the direction of movement of the gate. The further ridge may be located such that the central portion thereof is adjacent the vertex of the first ridge.
4 Brief Description of the Drawings 5 The invention will now be described, by way of example, with reference to the following drawings in which: Figure 1 is an upper perspective of a gate valve liner in accordance with the present invention; Figure 2 is an upper perspective view of the gate valve liner secured within a 10 gate valve; Figure 3 is a close up view of the valve body and gate valve liner of the present invention; Figure 4 is a cross sectional view of the gate valve liner of Figure 1; and Figure 5 is a cross sectional view of the gate valve and gate valve liner. 15 Detailed Description of Preferred Embodiments Referring to Figures, there is shown a gate valve liner 10 for use within a gate valve 12. The gate valve 12 is of a known configuration having a valve body 20 13 comprising a seat portion 14 and a valve chest portion 16. The seat portion 14 includes a bore 18 which is opened or closed in use by a gate 22. The valve body 13 is formed from a first body portion 20 and a second body portion 21. Each of the first and second body portions 20 and 21 forms half of 25 the valve body 13 and the halves are securable together by fasteners 24. Each of the first and second body portions 20 and 21 therefore includes a seat portion 14, a valve chest portion 16 and bores 18 that align when the body portions 20 and 21 are secured together. 30 The body portions 20 and 21 each include a recess 26 extending away from the bore 18 into the valve chest portion 16. The gate 22 is provided between the body portions 20 and 21 in the recesses 26 and is operable by an actuator 28. The actuator 28 is provided to move the gate 22 between a closed 5 position in which a first end of the gate 22 extends across the bore 18 of the gate valve 12 and an open position in which the gate 22 is withdrawn from the bore 18 to allow fluid to flow through the bore 18. 5 The gate valve liner 10 is provided to fit between the first and second body portions 20 and 21 and to line the inside of the recesses 26 and the bores 18 and seal between the valve body 13 and the gate 22. The gate valve liner 10 includes a chest portion 30 and a ring portion 32. The 10 chest portion 30 is received in the valve chest portion 16 and the ring portion 32 extends through the bore 18 in the seat portion 14. The chest portion 30 of the gate valve liner 10 comprises a first side wall 34 and a second side wall 35. First ends 36 of the first and second side walls 34 15 and 35 are arcuate in shape and adjoin a first side of the ring portion 32. The first and second side walls 34 and 35 define a chamber 38 into which is received the gate 22. Opposed edges of the first and second side walls 34 and 35 extending from the first end 36 to a second end 37 are joined by interconnecting walls 40. The chest portion 30 includes a collar 60 adjacent 20 the second end 37 thereof. The ring portion 32 comprises a generally cylindrical wall 42, the outer diameter of which is sized to be received within the openings 18 in the valve body 13. The length of the cylindrical wall 42 is such that the cylindrical 25 extends through the opening 18 from an outer surface of the first body portion 20 to an outer surface of the second body portion 21. An inner surface 44 of the cylindrical wall 42 defines an opening 46 through which fluid flows in use and across which the gate 22 seals when the gate valve 12 is closed. 30 The cylindrical wall 42 includes an aperture adjacent the first side thereof to receive the gate 22 such that the gate 22 can pass through the chest portion 30, through the aperture in the cylindrical wall 42 and across the opening 46.
6 The inner surface 44 of the cylindrical wall includes a groove 48 for receiving edges of the gate 22. The gate 22 includes a rounded end 23 which is received in the groove 48 to assist the gate 22 sealing across the opening 46. The groove 48 is provided such that the depth of the groove 48 decreases 5 towards a point on the second side of the ring portion 32, being the side opposite the chest portion 30 of the gate valve liner 10. As can be seen in Figure 1, the depth of the groove 48 decreases to zero adjacent the location on the inner surface 44 opposite the chest portion 30. 10 The depth of the groove 48 increases as the groove 48 extends away from this point in either direction such that the internal surface of the groove 48 is complementary in shape to the rounded end 23 of the gate 22. In the embodiment shown, the rounded end 23 is arcuate and the groove 48 increases in depth such that the distance between the internal surfaces of the 15 groove 48 on opposed transverse sides (that is, ninety degrees offset from the position at which the groove 48 is zero depth) is equal to the width of the gate 22. As can be seen in Figure 4, the first and second side walls 34 and 35 of the 20 chest portion 30 include one or more ridges 50 on the inner surfaces thereof. The ridges 50 are provided for sealing against the side surfaces of the gate 22 such that when the gate 22 is moved to the open position, the ridges 50 scrape against the gate 22 to remove any debris that could affect operation of the gate 22. 25 Each of the ridges 50 comprises a first side portion 52 and a second side portion 53. The first and second side portions 52 and 53 meet adjacent the centre of the side wall 34 or 35 at a vertex 54. In the embodiment shown, the first and second portions 52 and 53 of each ridge 50 are linear such that the 30 ridges 50 are generally V-shaped. The vertex 54 of a first of the ridges 50 is located adjacent the first side of the opening 46 and the vertex 54 of the second of the ridges 50 is offset from the vertex 54 of the first ridge 50 towards the second end 37 of the chest portion 30.
7 There is also provided a further ridge 56 on an inner surface of each of the first and second side walls 34 and 35. The further ridge 56 is a linear ridge extending across the inner surface of the side walls 34 or 35 in a direction transverse to the direction of movement of the gate 22. Each further ridge 56 5 is located such that the central portion thereof is adjacent the vertex 54 of the first of the ridges 50. In use, the shape of the ridges 50 aids in removing debris from the sides of the gate 22 when the gate 22 is moved. In particular, the arrangement of the 10 vertex 54 in each ridge 50 is provided to more effectively push through and dislodge any material that may have built up on the gate 22. When the gate 22 of the valve is raised, the build-up of material on the gate 22 travels with the gate and the V-shaped ridges rub against the gate surface. 15 The flakes of material are forcibly scraped off the face of the gate and pushed towards the sides of the V-shaped ridge. During the process of movement, the V-shaped ridges will cover the full width of the gate, thereby scraping the whole gate. The tolerances between the ridges and the gate will also prevent any slurry from rising into the chest cavity. 20 Also, the decreasing depth of the groove 48 reduces the build-up of material that may occur between the gate 22 and the groove 48 that could reduce the ability of the gate 22 to seal in the closed position. 25 It will be readily apparent to persons skilled in the relevant arts that various modifications and improvements may be made to the foregoing embodiments, in addition to those already described, without departing from the basic inventive concepts of the present invention.