Valve device

Abstract: A valve device comprises a seat (84) in the face of which are formed valve seats (83) spaced at regular intervals around the edge, each shaped into a concave form that corresponds to part of a spherical surface; a multiplicity of fluid passages (88) formed in the said valve seats as seat-through passages; valve-pieces arranged (85) in the valve seats, each valve piece having a spherical surface that corresponds to the surface of the valve seats; and a valve housing (87) provided with resilient means (86) that resiliently presses the valve-pieces onto the valve seat surfaces.

Description: The present invention relates to a valve device. The flow of fluid in pumps is limited and controlled by various types of valve devices. Figures 8 and 9 show a valve device used on plunger pumps, a type of pump which is often used for high-pressure applications. This valve device is constituted of a tubular seat 100, a valve-piece 102 provided with a surrounding flange 101, and a valve spring 103 which urges the valve-piece 102 against the seat 100. Because plunger pumps are used to pump materials such as cement clinker, in the conventional valve device solid particles entrained in the fluid may be caught between the valve-piece 102 and the seat 100. The tubular shape of the seat 100 used in the conventional valve device makes it easy for solid particles to pass through; in addition, because the seat 100 and the valve-piece 102 are made of metal the operation of the valve device may be adversely affected by solid particles that are caught therebetween. The result is that it has sometimes been impossible to pump a constant amount of fluid at a constant rate, so that operation of the pump was accompanied by a decline in efficiency. Furthermore, solid particles caught between the seat 100 and the valve-piece 102 can damage the seat and valve-piece, leading to leakage of fluid. Conventionally, therefore, the valve device has to be replaced at this point, which interrupts operations. EP-A-0 309 240 (which claims an earlier priority date than the present application but was published after any priority date of the present application) discloses a valve device for preventing inflow of solid particles present in fluid and increasing the durability of the device. Such a valve device (see Figures 10 and 11) comprises a seat 107 having a valve seat 104 formed as a concave surface 105 corresponding to part of a spherical surface, and a prescribed number of fluid passages 106 which are formed in the seat 107 and open into the concave surface 105. There are also a valve-piece 108 that has a surface corresponding to the shape of the concave surface 105 of the valve seat 104, and a valve cover 110 and spring retainer 111 that maintain the valve-piece 108 on the concave surface 105 of the seat 107 via a valve spring 109. In the valve device thus configured, at least one of the seat 107 and the valve-piece 108 is either formed of, or covered with, a hard resilient material, or one is formed of a hard resilient material and the other is covered with a hard resilient material. In addition, wood may be used instead of the hard resilient material. With the valve device thus configured, the fluid passages 106 formed in the seat 107 have a small diameter which makes it difficult for solid particles to pass therethrough. Even if solid particles should pass through the fluid passages 106 and get caught between the seat 107 and the valve-piece 108, the resilience of the valve seat and/or the valve-piece ensures that the functioning of the valve device will be not obstructed. However, a valve device thus configured is less adequate for pumping at higher pressures because increasing the amount being pumped causes the valve-piece 108 to vibrate during the inflow of fluid. BE-A- 520 270 discloses a valve device having the pre-characterising features of claim 1. US-A-1 092 782, US-A-3 298 320 and US-A-3 664 770 each discloses a valve device in which a plurality of fluid passages are provided before a valve seat but the valve seat is not spherically concave and the passages do not terminate at the valve seat surface but at a space before that surface. According to the present invention, there is provided a valve device comprising:- (a) a seat member in a face of which are formed a plurality of valve seats spaced at regular intervals around the edge; (b) a plurality of fluid passages in said seat member; (c) a plurality of valve pieces, each of the valve pieces being in a respective one of said valve seats and each having a spherical surface; and (d) a valve housing provided with resilient means that resiliently presses the spherical surfaces of the valve pieces on to the surfaces of the respective ones of the valve seats, characterised in that:- (e) each of said seats is of a concave shape with a surface that corresponds to part of a spherical surface, the spherical surface of each of the valve pieces corresponding to the surface of the respective valve seat; and (f) for each of said valve seats there is a respective plurality of such fluid passages in and through the seat member which communicate with and terminate at said surface of the valve seat. The present invention will now be described, by way of example, with reference to the accompanying drawings, in which:- Figure 1 is a cross-sectional view of an embodiment of an ultrahigh pressure pump; Figure 2 is a cross-sectional view of a valve device according to an example of the present invention for the pump; Figure 3 is a perspective view of the valve device of Figure 2 shown disassembled; Figure 4 is a plan view of the valve housing shown in Figure 3; Figure 5 is a cross-sectional view taken along line A--A of Figure 4; Figure 6 is a plan view of the seat member shown in Figure 2; Figure 7 is a cross-sectional view taken along line A--A of Figure 6; Figures 8 and 9 are a sectional view and a disassembled perspective view of a conventional valve device; and Figures 10 and 11 are a sectional view and a disassembled perspective view of a valve device not in accordance with the present invention. In Figure 1 ultrahigh fluid pump apparatus for use in a cement mill for example comprises a valve box 2 provided with a valve chamber 1, a plunger box 4 provided with a plunger 3, and a box 5 forming a pressure action chamber 5a disposed between the valve box 2 and the plunger box 4. The valve box 2 has an inlet passage 6 and an outlet passage 7 that communicate with the valve chamber 1 and which are provided with an inlet valve 80 and an outlet valve 81, respectively. A side wall 2a of the valve box 2 is provided with a passage 17 that connects the pressure-action chamber 5a with the valve chamber 1. As explained below, the position of the passage 17 is determined according to the difference in specific gravity between a liquid 28 and the fluid 14 to be pumped so that the latter does not enter the pressure action chamber 5a. When the liquid has a higher specific gravity than the fluid, the passage 17 is located at a higher position in the pressure-action chamber 5a, and when the liquid has a lower specific gravity the passage 17 is positioned lower. In the illustrated example, the position where the passage 17 opens into the pressure-action chamber 5a is higher than the inlet of the valve chamber 1. Thus, the position of the passage 17 is determined according to the relationship between the heights of the pressure-action chamber 5a and the valve chamber 1 and a consideration of the specific gravities of the liquid and the fluid 14. The end of the plunger 3 maintained within the cylinder 21 in the plunger box 4 via V-packing 22 projects into the pressure action chamber 5a and is reciprocated at high speed by a drive means (not illustrated). A resilient membrane 23 is provided in the pressure-action chamber 5a to divide the pressure-action chamber 5a into a cylinder 21 side A and a valve chamber 1 side B. The cylinder 21 side A of the resilient membrane 23 is filled with an operating medium 25, such as oil, via an oil passage 24 of the plunger box 4. In addition, the valve chamber 1 side B of the pressure action chamber 5a and part of the passage 17 are filled with liquid 28, such as oil, which has a lower specific gravity than the fluid 14 and does not mix with the fluid 14. The liquid 28 comes into contact with the fluid 14 part-way along the passage 17. Provided between the pressure action chamber 5a and the passage 17 is a screening member 29 that uses a mesh screen, for example, to prevent particles that exceed a given size from entering the pressure-action chamber 5a. The screening member 29 may be formed as an integral part of the valve box 5 which forms the pressure-action chamber 5a, and the passages 20 therein are set at a downward inclination toward the passage 17 side. With the above configuration, suction operation of the plunger 3 causes the resilient membrane 23 to contract, reducing the volume of the cylinder 21 side A of the pressure-action chamber 5a and increasing the volume on the valve chamber 1 side B. The change in volume results in a rise in the level of the liquid 28 in the passage 17. Also, an amount of fluid 14 corresponding to the change in volume flows into the valve chamber 1 as the inlet valve 80 opens. The expulsion operation of the plunger 3 causes the resilient membrane 23 to expand via the operating medium 25, and with the reduction in the volume of the valve chamber 1 side B the liquid 28 in the valve chamber 1 side B of the pressure-action chamber 5a is expelled. Also, the level of the liquid 28 in the passage 18 decreases and a corresponding amount of fluid 14 is forced out as the outlet valve 81 opens. The liquid 28 is only forced part-way along the passage 17 and does not flow over to the valve chamber 1 side. As shown in Figures 2 to 7, the inlet valve 80 and the outlet valve 81 each has a seat member 84 in the face 82 which are formed a multiplicity of valve seats 83 (eight, in the illustrated example) spaced at regular intervals around the edge, each being shaped into a concave form that corresponds to part of a spherical surface; spherical valve-pieces 85 arranged on the valve seats 83; and a valve housing 87 that presses the valve-pieces 85 onto the valve seats 83 by means of springs 86. For each of the valve seats 83 in the seat member 84 there are formed multiple fluid passages 88 (three in each case, in the illustrated example) that extend axially through the seat member 84 and communicate with and terminate at the valve seat surface. Disposed around the edge of the valve housing 87 are fluid passages 89 corresponding to the valve seats 83 and in which the valve-pieces 85 fit. The exit end of each of the fluid passages 89 is formed into a smaller diameter portion by a lip 90. One end of each of the valve springs 86 is held at the lip 90. The valve housing 87 and seat member 84 are provided with respective central bolt through-holes 91 and 92 whereby they are bolted together by a bolt 93 and a nut 94. In addition to metal, the valve-pieces 85 and/or the seat member 84 may be made of, or covered with, a hard resilient material such as synthetic resin, for example. With the above configuration, when suction operation of the plunger 3 causes the resilient membrane 23 to contract, reducing the volume on the cylinder 21 side A of the pressure-action chamber 5a, the result is that the valve-pieces 85 of the inlet valve 80 open against the resistance of the springs 86, and fluid 14 flows into the valve chamber 1. At this time, the valve-pieces 85 of the outlet 81 are drawn in the direction of their closed positions, and therefore remain closed. Before the fluid can flow into the valve chamber 1, entrained particles that exceed a given size are removed by the fluid passages 88 and then by the screening member 29. The expulsion operation of the plunger 3 expands the resilient membrane 23, causing fluid 14 that has entered the valve chamber 1 to open the outlet valve 81 and be pumped out. Because the operation of the valves 80 and 81 takes the form of small amplitude movements of the numerous valve-pieces 85, vibration accompanying the opening and closing action of the valves can be prevented and when applied to pumps can provide reliable valve function and increased durability, compared with conventional arrangements.

Claims: A valve device comprising:- (a) a seat member (84) in a face (82) of which are formed a plurality of valve seats (83) spaced at regular intervals around the edge; (b) a plurality of fluid passages (88) in said seat member; (c) a plurality of valve pieces (85), each of the valve pieces being in a respective one of said valve seats and each having a spherical surface; and (d) a valve housing (87) provided with resilient means (86) that resiliently presses the spherical surfaces of the valve pieces on to the surfaces of the respective ones of the valve seats, characterised in that:- (e) each of said seats is of a concave shape with a surface that corresponds to part of a spherical surface, the spherical surface of each of the valve pieces corresponding to the surface of the respective valve seat; and (f) for each of said valve seats there is a respective plurality of such fluid passages in and through the seat member which communicate with and terminate at said surface of the valve seat.

Inventors: KOIWA YOSHINOBU, KOIWA, YOSHINOBU
Applicants: FUJIMORI SHUICHI, KELBIN CO LTD, KOIWA YOSHINOBU, LITTLE ROCK LTD, FUJIMORI, SHUICHI, KABUSHIKI KAISHA LITTLE ROCK, KELBIN CO., LTD., KOIWA, YOSHINOBU
Application year: 1989
Main classification: F04B21
IPC codes: F04B43, F04B53