Pump and valve apparatus

Abstract: A pump consists of a valve box (2) in which a valve chamber (1) inlet (6) and outlet (7) are each provided with a valve, and a reciprocating member in a cylinder that communicates with the valve chamber (1) of the valve box (2) to open the said valves. A pressure action chamber (5) is provided between the valve box (2) and the cylinder (12) and a pressure force member divides the pressure action chamber (5) into a valve chamber side and a cylinder side. On the cylinder side of the pressure action chamber (5) thus divided is an action medium that transmits to the pressure force member changes in the volume of the pressure action chamber produced by the action of the reciprocating member. A valve means consists of a concave valve seat (19) and a number of fluid passages (20) formed therein opening into the said concavity. Either the valve seat or the valve-piece (9) is formed of, or covered with, a hard resilient material, or one is formed of the hard resilient material and the other is covered with a hard resilient material. The valve seat (19) and valve-piece (9) may be made of wood.

Description: This invention relates to a pump apparatus for pumping fluid containing solid bodies that provides a reliable valve opening and closing operation and improved durability. Pumps in use include reciprocating pumps in which the reciprocating action of a piston is used to open and close a valve and pressure-feed a fluid such as water, for example. Such reciprocating pumps are divided into three types according to the form of piston used: the bucket type, the plunger type and the piston type. As shown in Figure 12 of the accompanying drawings, bucket type pumps have a hole 102 in the piston 101 that slides in a cylinder 100. The hole 102 and the cylinder outlet 103 are provided with respective valves 104 and 105. The piston 101 is caused to move reciprocally via a piston rod 106. The descent of the piston 101 opens the valve 104 and closes the valve 105, drawing water through the hole 102 to the upper part of the cylinder 100. This water in the upper part of the cylinder 100 is then sent out under pressure by the rise of the piston 101. Plunger type pumps, such as shown in Figure 13 of the accompanying drawings, are generally used for high-pressure applications. Water, for example, in the cylinder 107 is forced under pressure out of the cylinder 108' by the insertion of the plunger 108 into the cylinder 107. Figure 14 of the accompanying drawings shows a piston type pump in which the movement of a piston 111 driven by a crank mechanism 109 inside a cylinder 110 opens and closes valves 112 and 113 to feed out the water under pressure. These types of reciprocating pumps use various types of packing, for example rubber, to obtain a watertight seal between the piston and the cylinder. In the bucket pump there is a packing between the cylinder 100 and the piston rod 106, and in the plunger pump the cylinder 107 and plunger 108 are each provided with a packing therebetween. On the piston pumps, piston rings are provided around the circumference of the piston 111. When these types of conventional reciprocating pumps, especially plunger pumps, are used to pump fluids containing granular material, such as in a cement mill, the motion of the plunger is accompanied by a rubbing of the particles against the packing, which causes the packing to wear rapidly. This has necessitated replacing packings at short intervals, which reduces operating efficiency and shortens the working life of the pump itself. On piston pumps, the piston rings wear and can cause damage to the internal surface of the cylinder. Various types of valves are used as means of limiting or controlling the fluid flow. Figures 8 and 9 show a valve device used on plunger pumps which are well-known as pumps for high-pressure applications. These valve devices comprise a tubular valve seat 50, a valve-piece 52 provided with a surrounding flange 51, and a valve spring 53 which presses the valve-piece 52 towards the valve seat 50. With plunger pumps used to pump materials such as cement clinker, for example, as the valve-piece 52 of the conventional valve device opens and closes solid bodies contained in the fluid can be caught between the valve-piece 52 and the valve seat 50. Because the valve seats 50 used in conventional valve devices are tubular members solid bodies readily pass therethrough, in addition to which as the valve seat 50 and the valve-piece 52 are made of metal, the valve operation is not always reliable if solid bodies are caught therebetween. This can make it impossible to pump constant quantities of fluid at fixed intervals, so use of the pump was accompanied by a lowering of the operating efficiency. Furthermore, solid bodies caught between the valve seat 50 and the valve-piece 52 could cause damage to the seat and valve-piece, resulting in fluid leaking out of the gap between them. Conventionally, therefore, the valve device has had to be replaced at this point, interrupting operations. US-A-1 650 377, US-A-3 520 643, DE-C-577 401 and US-A-4 080 107 all disclose pump apparatus comprising a valve box in which a valve chamber inlet and outlet are each provided with a valve, and a reciprocating member which moves reciprocally in a cylinder that communicates with the valve chamber of valve box to open the said valves, wherein a pressure action chamber is provided between the valve box and the cylinder and a pressure force member divides the pressure action chamber into a valve chamber side and a cylinder side, and contained on the cylinder side of the pressure action chamber divided by the pressure force member is an action medium that transmits to the pressure force member changes in volume of the pressure action chamber produced by the action of the reciprocating member. US-A-1 092 782 discloses a gas compressor valve mechanism with an inlet valve seat having a generally concave surface with a plurality of fluid passages therein through which the fluid passes. According to the invention there is provided a pump apparatus for pumping a fluid containing solid bodies, the apparatus comprising a valve box having a valve chamber inlet, a valve chamber outlet and a valve chamber therebetween;a pressure action chamber positioned adjacent said valve box and in fluid communication therewith; and a pressure force member positioned in said pressure action chamber and dividing said pressure action chamber into a valve chamber side and a cylinder side, said cylinder side of the pressure action chamber containing an action medium; characterised in that an inlet valve seat provided in said valve chamber inlet has a generally concave surface with a plurality of fluid passages therein through which the fluid passes, said plurality of fluid passages straining said fluid to prevent large solid pieces in said fluid from passing therethrough, said fluid passages having outlets which are distributed around the generally concave surface of the inlet valve seat, said generally concave surface having an outer edge, some of the outlets being positioned at different distances from the outer edge of the generally concave surface than other outlets of the plurality of fluid passages; in that a valve-piece is moveable toward and away from said inlet valve seat to respectively close and open said plurality of fluid passages; in that a reciprocable member is moveable in a cylinder adjacent the cylinder side of the pressure action chamber to transmit changes in volume of said cylinder side to said pressure force member thereby to move said pressure force member, movement of said pressure force member upon reciprocation of said reciprocable member in one direction causing said valve-piece to move to close said plurality of fluid passages and causing fluid in said valve chamber to be discharged therefrom, and movement of said reciprocable member in a direction opposite to said one direction causing said valve-piece to move to open said plurality of fluid passages and causing fluid to be drawn into said valve chamber through said plurality of fluid passages; and in that said inlet valve-piece has a generally convex surface which conforms to the generally concave surface of the inlet valve seat, said generally convex surface of the valve-piece being positioned against the generally concave surface of the inlet valve seat when said inlet valve-piece closes the inlet valve seat. In operation the suction effect of the reciprocable member causes the volume enclosed by the pressure force member to contract by a set amount, which produces a negative pressure in the valve chamber that opens the valve on the inlet side, drawing fluid into the interior of the valve chamber. When the reciprocable member performs an expulsion action, the pressure force member is expanded, via the action medium, by the volume of the expulsion movement of the reciprocable member. As a result, the outlet-side valve opens and an amount of fluid is fed out that is the amount of the change in volume of the pressure action chamber. The fluid passages formed in the valve seat are small, which makes it hard for solid bodies to pass therethrough. Even if solid bodies should pass through the fluid passages and get caught between the valve seat and the valve-piece, the resilience if the valve seat and/or the valve-piece ensure that such solid bodies do not interfere with the action of the valve. For a better understanding of the invention and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which: Figure 1 is a cross-sectional view of an embodiment of pump apparatus according to the present invention; Figure 2 is a cross-sectional view of the valve device shown in Figure 1; Figure 3 is a perspective view of the device provided in the pump apparatus; Figures 4 to 7 are cross-sectional views of other embodiments of the invention; Figure 8 is a cross-sectional view of a conventional valve device; Figure 9 is a perspective view of a conventional valve device; Figure 10 is an explanatory drawing to explain the operation of the pump apparatus of Figure 1; Figure 11 is a cross-sectional view of a portion of another embodiment; and Figures 12 to 14 are cross-sectional views of various forms of conventional pump apparatus. Referring first to Figure 1, this pump apparatus includes a valve box 2 provided with a valve chamber 1, a plunger box 4 provided with a plunger 3, and a pressure action chamber 5 disposed between the valve box 2 and the plunger box 4. The valve box 2 is provided with a valve device 11 that includes a valve chamber inlet 6 and outlet 7, valve seats 8 and 8', valve-pieces 9 and 9' and valve springs 10, 10', which are described later. The plunger 3 is disposed, via a plurality of V-shaped packings 13, within a cylinder 12 in the plunger box 4 and is slidably operated by a drive means (not illustrated). In the suction process the plunger 3 is contained in the cylinder 12, and in the expulsion process part of the plunger 3 is caused to project from the opening 14 of the cylinder 12 into the pressure action chamber 5. The pressure action chamber 5 is provided between an opening 15 provided in the wall of the valve chamber 1 of the valve box 2 and the cylinder opening 14 of the plunger box 4. In the pressure action chamber 5 is provided a resilient membrane 16 made of sheet rubber, for example, to form a pressure force member that divides the pressure action chamber 5 into a valve box 2 side and a plunger box 4 side. The enclosed cylinder-side action chamber A formed by the partitioning resilient membrane 16 is filled with an action medium 17 such as oil, for example. The valve seats 8, 8', valve-pieces 9, 9' and valve springs 10, 10' that form the valve device 11 will now be described with reference to Figures 2 and 3. Each valve seat 8, 8' has a valve seating portion 18 with a concave surface 19 that corresponds to part of a spherical surface, and is also provided with a number of fluid passages 20 that extend axially to open into the said concave surface 19. The number and diameter of the fluid passages 20 are determined beforehand to values that ensure the achievement of the required flow application. The transverse section of the fluid passages 20 may be reticular or split-shaped, as required. Each valve-piece 9, 9' is spherical in shape and is formed from a hard resilient material such as hard rubber or synthetic resin. The diameter of each valve-piece 9, 9' is such that it fits the concave surface 19 or is slightly larger. Each valve seat 8, 8' as well as each valve-piece 9, 9' may also be formed of a hard resilient material, or each valve seat 8, 8' alone may be formed of a hard resilient material. The valve spring 10 is provided between a valve cover 21 and a spring retainer 22, for example, as shown in Figure 2 or, as shown in Figure 1, between the valve cover and the valve seat 8'. The valve spring 10' is provided between a valve cover of the valve-piece 9' and a cap 25 of the valve box 2 as shown in Figure 1. The valve springs 10, 10' urge the valve-pieces 9, 9' towards the valve seats 8, 8' with a constant force. The operation of the apparatus will now be described. When in the course of the suction process the plunger 3 is moved to the left, with reference to the drawing, the resilient membrane 16 contracts by the amount of change in volume caused by the suction action of the plunger 3. This produces a negative pressure in chamber 1, forcing open the valve-piece 9 against the resistance of the valve spring 10, and the fluid substance flows into the valve chamber 1 via the fluid passages 20. During the expulsion process, when the plunger 3 is moved to the right, with reference to the drawing, the resilient membrane 16 expands via the action medium 17 by the amount of change in volume produced by the expulsion stroke of the plunger 3. As a result, the fluid introduced into the valve chamber 1 pushes open the valve-piece 9' on the outlet side against the resistance of the valve spring 10'. An amount of fluid equivalent to the amount of change in volume caused by the expansion of the resilient membrane 16 is fed under pressure through the fluid passages 20. Because the fluid passages 20 are small holes, any solid bodies included in the fluid that are above a set size are excluded by the valve seat 8, so that only smaller solid particles are allowed to pass through the valve device 11. Even if solid bodies should be caught between the valve seat 8 and the valve-piece 9, the valve seat 8 or the valve-piece 9 are formed of a hard resilient material which deforms, thereby enabling the seal to be maintain. Figures 4 to 6 illustrate other embodiments of the present invention. Parts that are the same as those in Figure 2 are denoted by the same reference numerals. In the embodiment shown in Figure 4, the valve seat 8 is covered with a hard resilient material 24 such as hard rubber or synthetic resin. The valve-piece 9 may be covered in the hard resilient material 24 such as shown in Figure 5, or both the valve seat 8 and valve-piece 9 may be covered by the hard resilient material 24. In Figure 6, the valve-piece 9 formed of hard resilient material may be combined with a valve seat 8 covered with hard resilient material. All these possible combinations apply also to the valve seat 8' and the valve-piece 9'. Shown in Table 1 are the combinations of valve-piece 9 or 9' and valve seat 8 or 8'. A valve-piece 9 or 9', and a valve seat 8 or 8', made of wood may also be used in place of the aforementioned hard resilient material. In this case, the water contained in the wooden valve-piece 9 or 9' and the valve seat 8 or 8' generates a restorative force, so that even if solid bodies are caught between the valve-piece 9 or 9' and the valve seat 8 or 8' there is little deformation thereof. The valve-piece 9 or 9' may be spherical in shape, as shown in Figure 7, and the curvature may be ellipsoid rather than the curve of a perfect sphere. The inlet-side valve-piece 9 opening in the direction of the valve chamber 1 is normally kept closed by the force of the valve spring 10 urging it in the direction of the valve seat 8. The outlet-side valve-piece 9' that opens away from the valve chamber 1 is normally kept closed by the force of the return spring 10', provided between the cap 25 of the valve box 2 and the valve-piece cover, that urges the valve-piece 9' towards the valve seat 8'. The numeral 15 denotes the opening formed in the wall 2a of the valve chamber 1. The plunger 3 is disposed, via a V-shaped packing 13, within a cylinder 14 in the plunger box 4 and is slidably operated by a drive means (not illustrated). In the suction process the plunger 3 is contained in the cylinder 14, and in the expulsion process part of the plunger 3 is caused to project from the opening of the cylinder 14 into the pressure action chamber 5. The pressure action chamber 5 is provided between the opening 15 provided in the wall of the valve chamber 1 of the valve box 2 and the cylinder opening of the plunger box 4. In the pressure action chamber 5 is provided a resilient membrane 16 made of sheet rubber, for example, to form a pressure force member that divides the pressure action chamber 5 into a valve box 2 side and a plunger box 4 side. The partitioning resilient membrane 16 is pressed into and around a concave portion 31 formed in the end face of the opening of the box forming the pressure action chamber 5 and is fixed by means of an end-plate 32. On the side of cylinder 14, the enclosed action chamber A formed by the partitioning resilient membrane 16 is filled with an action medium 17 such as oil, for example. The operation of the apparatus of the above construction will now be described. When in the course of the suction process the plunger 3 is moved to the left, with reference to the drawing, as shown by Figure 10 the resilient membrane 16 contracts by the amount of change in volume caused by the suction of the plunger 3. This produces a negative pressure in chamber 1, forcing open the valve-piece 9 against the resistance of the valve spring 10, and the fluid substance flows into the valve chamber 1 via the fluid passages 20. During the expulsion process, when the plunger 3 is moved to the right, with reference to the drawing, the resilient membrane 16 expands via the action medium 17 by the amount of change in volume produced by the expulsion stroke of the plunger 3. As a result, the fluid introduced into the valve chamber 1 pushes open the valve-piece 9' on the outlet side against the resistance of the valve spring 10', sending through a fixed amount of fluid under pressure. Figure 11 illustrates another embodiment of the invention. Here, a bellows member 92 is used as the pressure force member. Similarly to the preceding embodiments, the inside of the bellows member 92 is filled with an action medium 17 such as oil. Numeral 93 denotes a return spring for the bellows member 92. In this embodiment too, in the suction process of the plunger 3 the bellows member 92 is contracted by the spring 93, drawing the fluid substance into the valve chamber 1. In the expulsion process of the plunger 3, the bellows member 92 is expanded via the action medium 17, and an amount of fluid equivalent to the amount of change in the volume thereof is fed under pressure. As has been described in the foregoing, as in the pump apparatus according to the present invention the valve seats and/or the valve-pieces are resilient, the opening and closing action is not obstructed even if solid bodies are caught between the valve seats and the valve-pieces. Also, a multiplicity of fluid passages are formed in each valve seat, and small sectional area of each of these passages enables large solid bodies to be excluded. In addition to this, it is difficult for each valve seat and valve-piece to be damaged by solid bodies or the like, which increases durability. Use of a wooden valve seat or valve-piece is cheaper and more economical than making them of metal. With the pump apparatus according to the present invention the fluid can be fed under pressure by changes in the volume of a pressure force member, so that the packing used to maintain the watertightness of the reciprocating member does not come into contact with the fluid. In case of pressurized pumping of, for example, cement-mill materials and the like, this helps to increase the durability as there is no risk of the seal being damaged. Furthermore, the location of the pressure action chamber between the valve chamber and the cylinder is highly economical, because it can be used with conventional plunger and other pumps without modification.

Claims: A pump apparatus for pumping a fluid containing solid bodies, the apparatus comprising a valve box (2) having a valve chamber inlet (6), a valve chamber outlet (7) and a valve chamber (1) therebetween;a pressure action chamber (5) positioned adjacent said valve box (2) and in fluid communication therewith; and a pressure force member (16,92) positioned in said pressure action chamber (5) and dividing said pressure action chamber into a valve chamber side and a cylinder side, said cylinder side of the pressure action chamber containing an action medium (17); characterised in that an inlet valve seat (8) provided in said valve chamber inlet (6) has a generally concave surface (19) with a plurality of fluid passages (20) therein through which the fluid passes, said plurality of fluid passages straining said fluid to prevent large solid pieces in said fluid from passing therethrough, said fluid passages having outlets which are distributed around the generally concave surface of the inlet valve seat (8), said generally concave surface (19) having an outer edge, some of the outlets being positioned at different distances from the outer edge of the generally concave surface than other outlets of the plurality of fluid passages; in that a valve-piece (9) is moveable toward and away from said inlet valve seat (8) to respectively close and open said plurality of fluid passages (20); in that a reciprocable member (3) is moveable in a cylinder (12) adjacent the cylinder side of the pressure action chamber (5) to transmit changes in volume of said cylinder side to said pressure force member (16,92) thereby to move said pressure force member, movement of said pressure force member upon reciprocation of said reciprocable member (3) in one direction causing said valve-piece (9) to move to close said plurality of fluid passages (20) and causing fluid in said valve chamber (1) to be discharged therefrom, and movement of said reciprocable member (3) in a direction opposite to said one direction causing said valve-piece (9) to move to open said plurality of fluid passages (20) and causing fluid to be drawn into said valve chamber (1) through said plurality of fluid passages; and in that said inlet valve-piece (9) has a generally convex surface which conforms to the generally concave surface of the inlet valve seat (8), said generally convex surface of the valve-piece (9) being positioned against the generally concave surface of the inlet valve seat (8) when said inlet valve-piece closes the inlet valve seat. The pump apparatus according to claim 1 wherein the pressure force member is a resilient, flexible membrane (16). The pump apparatus according to claim 1, wherein the pressure force member is a bellows-type member (92) capable of expansion and contraction. The pump apparatus according to claim 1, 2 or 3, wherein the reciprocable member is a plunger (3) of a plunger type pump. The pump apparatus according to claim 4, wherein the reciprocable member is a piston of a piston type pump. The pump apparatus according to any one of the preceding claims and further comprising: an outlet valve seat (8') provided in said valve chamber outlet (7), said outlet valve seat having a plurality of fluid passages (20) therein; and an outlet valve-piece (9') movable toward and away from said outlet valve seat (8') to respectively close and open said plurality of fluid passages therein, said outlet valve-piece (9') moving away from said outlet valve seat (8') when said pressure force member (16,92) moves upon reciprocation of said reciprocable member (3) in said one direction thereby to permit discharge of the fluid from the valve chamber (1), and said outlet valve-piece (9') moving toward said outlet valve seat (8') when said pressure force member (16,92) moves upon reciprocation of said reciprocable member (3) in the direction opposite to said one direction thereby to close said plurality of fluid passages (20) in said outlet valve seat (8') to prevent discharge of fluid through said plurality of fluid passages in said outlet valve seat as said fluid is being drawn into said valve chamber (1) through said plurality of fluid passages (20) in said inlet valve seat (8). The pump apparatus according to claim 6, wherein the outlet valve seat (8'), has a generally spherical surface and wherein the inlet valve-piece (9) and outlet valve-piece (9') both have generally spherical surfaces which match with the respective generally concave and generally spherical surfaces of the inlet valve seat (8)and outlet valve seat (8') and further comprising means (10) for urging the inlet valve-piece (9) toward the inlet valve seat (8) and means (10') for urging said outlet valve-piece (9') toward the outlet valve seat (8'). The pump apparatus according to any one of the preceding claims, wherein at least one of said inlet valve seat (8) and said valve-piece (9) are covered with a hard resilient material, said resilient material being one of a hard rubber and a synthetic resin. The pump apparatus according to any one of claims 1 to 8, wherein the or each plurality of fluid passages (20) in transverse section are reticular in shape. The pump apparatus according to any one of claims 1 to 8, wherein the or each plurality of fluid passages in transverse section are slit-shaped.

Inventors: 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: 1988
Main classification: F04B21
IPC codes: F16K15, F04B53