sleeve valve

Abstract

To suppress generation of cavitation by low-cost means without increasing in a size of a device, in a sleeve valve.SOLUTION: A sleeve valve comprises: a valve box 11 with both ends open; an inflow pipe 1 and an outflow pipe 2 connected to the valve box 11; a cylinder 12 that is arranged in the valve box 11, and whose side of the inflow pipe 1 is closed; and a sleeve valve element 13 that is housed in the cylinder 12 and is movable relative to a cylinder axis direction. When a valve element valve seat 14b provided on the valve body 11 and a valve element valve seat 14a provided on the sleeve valve element 13 contact / separate from each other, the sleeve valve opens / closes a gap 6 between an end part 12c of the cylinder 12 on the outflow pipe 2 side and the valve element valve seat 14b. A flow path 4 on a downstream side of the valve element valve seat 14b is provided with a flow path protrusion 31 that protrudes from an inner surface 4a of the flow path 4 toward an axial core p side of the flow path 4.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a sleeve valve installed in water supply pipes in water and sewage systems, industrial water supply, agricultural water supply, dams, etc., and other supply pipes for various fluids.

Background Art

[0002] For example, a sleeve valve is used as a valve device for opening and closing water supply pipes in water and sewage systems, industrial water supply, agricultural water supply, dams, etc. The sleeve valve has a cylindrical sleeve as a valve body, and the flow rate of the fluid supplied to the downstream side can be adjusted by the forward and backward movement of the sleeve in the axial direction of the cylinder in the casing. In addition, the sleeve valve is often used particularly in places where high-head water such as in dams is reduced in pressure and discharged downstream, or where water is discharged with reduced pressure from the discharge port of a pressure water supply pipe.

[0003] The structure of the sleeve valve is, for example, as shown in Patent Document 1. An inflow pipe is connected to one end of a cylindrical valve box, and an outflow pipe is connected to the other end. A cylinder is arranged in the valve box. The cylinder has its end on the inflow pipe side closed and its end on the outflow pipe side open. A cylindrical sleeve valve body with open axial ends is inserted into the cylinder, and the sleeve valve body is movable forward and backward along the axial direction of the cylinder (i.e., the flow direction connecting the inflow pipe and the outflow pipe) with respect to the valve box and the cylinder.

[0004] Also, a valve shaft is inserted into the valve box, and the valve shaft rotates around its axis by a handle, a driving machine, etc. A crank is connected to the valve shaft, and a connecting rod is rotatably connected to the tip of the crank to form a link mechanism. Further, the tip of the connecting rod is rotatably connected to a boss of the sleeve valve body. Therefore, when the valve shaft rotates around its axis, the sleeve valve body moves along the axial direction of the cylinder via the link mechanism, and accordingly, the opening degree of the sleeve valve body can be switched.

Prior Art Documents

Patent Documents

[0005] [Patent Document 1] Japanese Patent Publication No. 2020-153466 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] In this type of sleeve valve, the differential pressure between the inlet and outlet piping is often large depending on the operating conditions. As a result, water flowing out through the gap between the valve seat on the sleeve valve body side and the valve seat on the valve casing side can cause cavitation near the inner wall of the outlet piping.

[0007] For example, Figure 5 shows the main part of a sleeve valve 50. A cylinder 52 is located inside a valve body 51, and a sleeve valve body 53 is movable back and forth within the cylinder 52. This back and forth movement opens and closes the gap 56 between the valve seat 54a on the sleeve valve body 53 side and the valve seat 54b on the end wall 51a on the valve body 51 side. Water flows in from an annular guide channel 55 located outside the cylinder 52 as shown by arrow A, and this water flows out to the outlet pipe 57 side through the gap 56 between the valve seat 54a and the valve seat 54b. The water is sent out on the outlet pipe 57 side as shown by arrow B in the figure, but at this time, a vortex as shown by arrow C may be generated near the inner wall of the outlet pipe 57. The region in which such a vortex is generated is called a dead water zone, and a local pressure drop occurs in this dead water zone, which is considered to be the cause of cavitation.

[0008] Generally, cavitation is suppressed by injecting air from the outside to the inside of the valve body (e.g., Japanese Utility Model Publication No. 6-62268). However, depending on the fluid conditions, air injection may not reliably suppress cavitation, and especially in sleeve valves, there is a need to suppress cavitation more effectively under high differential pressure hydraulic conditions.

[0009] Furthermore, there is a method to suppress cavitation by injecting air into the pipes (air supply), but in applications such as water supply, injecting air from the outside is not common in order to prevent foreign matter from contaminating the water. For this reason, depending on the fluid, it may be necessary to suppress cavitation by modifying the valve structure.

[0010] Furthermore, as shown in Patent Document 1, using a porous link sleeve valve (see Figure 3 in Patent Document 1) with numerous small holes in the sleeve valve body is effective in suppressing cavitation. However, although porous link sleeve valves are more economical than screw-type porous sleeve valves of the same type, they have economic challenges in that they require processing costs for the porous sleeve, the valve body becomes longer due to the longer stroke, and the valve becomes larger due to the large loss coefficient when fully open. In addition, porous link sleeve valves also have the problem of requiring a large installation space due to their length.

[0011] Therefore, the objective of this invention is to suppress the generation of cavitation in a sleeve valve by low-cost means without increasing the size of the device. [Means for solving the problem]

[0012] To solve the above problems, this invention provides a sleeve valve comprising a valve body with both ends open, an inlet pipe connected to one end of the valve body and an outlet pipe connected to the other end, a cylinder disposed within the valve body with the inlet pipe side closed, and a sleeve valve body housed within the cylinder and movable relative to the cylinder along the cylindrical axis, wherein the gap between the outlet pipe side end of the cylinder and the valve body valve seat opens and closes as the valve body valve seat provided on the sleeve valve body moves toward and away from the valve body valve seat provided on the sleeve valve body, and employs a sleeve valve with a flow path projection that protrudes from the inner surface of the flow path toward the axial side of the flow path in the flow path downstream of the valve body valve seat.

[0013] Here, a configuration can be adopted in which the flow channel projection is provided with a through hole connecting the upstream side surface and the downstream side surface of the flow channel projection.

[0014] Furthermore, the inner surface of the through-hole can be configured to have a tapered section where the cross-section becomes smaller from the upstream side to the downstream side.

[0015] Furthermore, a configuration can be adopted in which the center line of the through-hole is parallel to the axis of the flow path. [Effects of the Invention]

[0016] This invention can suppress the occurrence of cavitation in sleeve valves. [Brief explanation of the drawing]

[0017] [Figure 1] A longitudinal cross-sectional view showing one embodiment of this invention. [Figure 2] Section II-II in Figure 1 [Figure 3] Enlarged cross-sectional view of key parts showing fluid flow [Figure 4] Enlarged view of Figure 3 [Figure 5] Cross-sectional view of a key part showing a conventional example. [Modes for carrying out the invention]

[0018] Embodiments of this invention will be described based on the drawings. Figures 1 and 2 are longitudinal cross-sectional views of the sleeve valve 10 of this embodiment.

[0019] The sleeve valve 10 is configured as a cylindrical valve body 11 with both ends open. An inlet pipe 1 is connected to one end, which is the inlet side, and an outlet pipe 2 is connected to the other end. Inside the valve body 11, a cylindrical cylinder 12 is arranged coaxially with the valve body 11. The end of the cylinder 12 on the inlet pipe 1 side is closed at a tapered tip, so that the fluid flowing from the inlet pipe 1 side into the introduction section 3 inside the valve body 11 is smoothly guided to the annular guide channel 5 on the outer diameter side of the cylinder 12.

[0020] Inside the cylinder 12, a cylindrical sleeve valve body 13 with open ends in the axial direction is inserted. The sleeve valve body 13 is movable forward and backward along the cylinder axis direction with respect to the valve box 11 and the cylinder 12, that is, along the fluid flow direction connecting the inflow pipe and the outflow pipe.

[0021] The sleeve valve body 13 of the embodiment is cylindrical and its outer surface 13a is a cylindrical surface. The upstream side of the sleeve valve body 13 functions as a guide portion that fits and slides on the inner circumference 12a of the cylinder 12, and the downstream side functions as a valve body portion that opens and closes the flow path. The tip of the valve body portion of the sleeve valve body 13 is a valve body valve seat 14a with a downward slope toward the downstream side. A gap (valve hole) 6 through which fluid passes is formed between the end portion 12c on the outflow pipe 2 side of the cylinder 12 and the end wall 19 on the outflow pipe 2 side of the valve box 11. Also, the corner portion of the valve box 11 on the outflow pipe 2 side of the gap 6, that is, the inner diameter side end of the end wall 19 serves as the valve box valve seat 14b.

[0022] The valve body valve seat 14a consists of an inclined surface formed at the same inclination angle (same slope) as the valve box valve seat 14b with respect to the cylinder axis direction of the valve box 11. As the sleeve valve body 13 moves in the cylinder axis direction, the valve body valve seat 14a of the sleeve valve body 13 contacts and separates from the valve box valve seat 14b, thereby opening and closing the gap 6 between the end portion 12c of the cylinder 12 and the valve box valve seat 14b, that is, opening and closing the sleeve valve 10.

[0023] Inside the valve box 11, a valve shaft 15 is inserted perpendicular to the cylinder axis direction of the valve box 11. The valve shaft 15 rotates around its axis by a driving force such as a motor or by the rotational operation of the handle 21 shown in FIG. 2.

[0024] A crank 17a is connected to the valve stem 15, and a connecting rod 17b is rotatably connected to the tip of the crank 17a, forming a linkage mechanism 17. The tip of the connecting rod 17b is rotatably connected to a boss 18 of the sleeve valve body 13. Therefore, when the valve stem 15 rotates around its axis, the sleeve valve body 13 moves along the cylindrical axis via the linkage mechanism 17, and this movement allows the sleeve valve body 13 to be switched between a fully open state and a fully closed state. Furthermore, by holding the sleeve valve body 13 at any opening position between the fully open state and the fully closed state, the discharge amount can be adjusted according to that opening.

[0025] For example, as shown by the solid lines in Figures 1 and 2, in the open state where the valve seat 14a of the sleeve valve body 13 is not in contact with the valve seat 14b of the valve casing 11, fluid from the inlet pipe 1 flows out through the annular guide channel 5 between the inner surface of the valve casing 11 and the outer surface of the cylinder 12, and through the valve hole 6 between the valve seat 14a and the valve seat 14b to the outlet pipe 2. Also, for example, as shown by the dashed lines in Figures 1 and 2, in the closed state where the valve seat 14a of the sleeve valve body 13 is in contact with the valve seat 14b of the valve casing 11, fluid from the inlet pipe 1 remains in the annular guide channel 5 between the inner surface of the valve casing 11 and the outer surface of the cylinder 12, and does not flow out to the outlet pipe 2.

[0026] In Figure 1, the axis o of the valve stem 15, that is, the fixing point (center of rotation) of the crank 17a to the valve stem 15, and the connection point b between the connecting rod 17b and the boss 18, are located on the centerline p of the valve body 11 in the piping direction (centerline in the cylindrical axis direction), and the connection point a between the crank 17a and the connecting rod 17b is offset in one direction from the centerline p in the piping direction. The arrangement of these axes o, connection point a, connection point b, and centerline p in the piping direction, or the configuration of the link mechanism 17, can be changed as appropriate.

[0027] In the open state, water from the inlet pipe 1 flows through the annular guide channel 5 and through the gap 6 to the outlet pipe 2. In conventional sleeve valves, a dead water zone is generated near the inner wall of the outlet pipe, causing cavitation. However, according to this invention, the flow channel 4 downstream of the valve body seat 14b is provided with a flow channel projection 31 that protrudes from the inner surface 4a of the flow channel 4 toward the axis p of the flow channel 4, thereby suppressing the occurrence of cavitation. Furthermore, since the occurrence of cavitation can be suppressed by the installation of the flow channel projection 31, there is no need to provide various cavitation prevention means such as intake means or providing a large number of holes in the sleeve valve body 13 as in the conventional method. For this reason, the overall device of the sleeve valve 10 can be simplified, and the stroke can be reduced, resulting in a smaller device.

[0028] Furthermore, as shown in Figures 3 and 4, if a through-hole 32 is provided in the flow channel projection 31, connecting the upstream side surface 31a and the downstream side surface 31b of the flow channel projection 31, an even higher cavitation suppression effect can be expected. This is because, with the through-hole 32, water can more easily enter the back side (downstream side) of the flow channel projection 31 through the through-hole 32, making the effect of eliminating dead water areas more pronounced.

[0029] Furthermore, it is desirable that the flow channel projection 31 be adjacent to the downstream side of the valve casing seat 14b, and in particular, that the inclined surface of the valve casing seat 14b and the upstream side surface 31a of the flow channel projection 31 be continuous. That is, it is desirable that the inner diameter side end of the inclined surface of the valve casing seat 14b and the outer diameter side end of the upstream side surface 31a of the flow channel projection 31 be connected. However, as long as the effect of suppressing the generation of dead water areas can be expected, it is also possible to adopt a configuration in which the inner diameter side end of the inclined surface of the valve casing seat 14b and the outer diameter side end of the upstream side surface 31a of the flow channel projection 31 are not directly connected, and the two are separated in the direction of the cylinder axis. In this case, it is desirable that the valve casing seat 14b and the flow channel projection 31 located downstream of it be as close as possible along the direction of the cylinder axis.

[0030] Furthermore, it is even more preferable that the inclined surface of the valve body seat 14b and the upstream side surface 31a of the flow channel projection 31 have the same inclination angle (same gradient) with respect to the center line p in the piping direction. Figures 3 and 4 show that the inclined surface of the valve body seat 14b and the upstream side surface 31a of the flow channel projection 31 are continuous inclined surfaces with the same inclination angle.

[0031] In this embodiment, as shown in Figures 3 and 4, the inner surface 32a of the through hole 32 is configured to have a tapered section in which the cross-section becomes smaller from the upstream side to the downstream side. By providing the tapered section, the flow coefficient of the through hole 32 is increased, and the flow rate supplied to the back side (downstream side) of the flow channel projection 31 is increased. It is desirable that the tapered section provided on the inner surface 32a of the through hole 32 extends along the entire length of the through hole 32, but it may also be a portion of the through hole 32 along its length.

[0032] In this embodiment, as shown in Figure 4, the tapered portion is set along the entire length of the through hole 32, and the inner diameter (diameter) d1 of the downstream outlet is set to be smaller than the inner diameter (diameter) d2 of the upstream inlet. Furthermore, the inclination angle of the tapered portion is kept constant along the entire length of the through hole 32, and the entire tapered portion is formed as a conical surface.

[0033] It is preferable that the flow channel projection 31 is provided continuously along the entire circumference of the inner surface 4a of the flow channel 4, but it may also be provided intermittently in the circumferential direction along the inner surface 4a of the flow channel 4. Furthermore, the ratio of the radius of the circle formed by the inner surface of the top of the flow channel projection 31 (see symbol r1 in Figure 4) to the radius of the circle formed by the inner surface 4a of the flow channel 4 (see symbol r2 in Figure 4) can be appropriately set according to the characteristics of the flow channel in which the sleeve valve 10 is installed and the characteristics of the water (fluid).

[0034] In this embodiment, the center line q of the through hole 32 is parallel to the center line (axis) p of the flow path 4 in the piping direction, so that the water passing through the through hole 32 is smoothly guided downstream along the inner surface 4a of the flow path 4. However, the center line q of the through hole 32 may be set to have an angle (45° > angle > 0°) with respect to the center line (axis) p of the flow path 4 in the piping direction. For example, the center line q of the through hole 32 may be configured to be inclined toward the outer diameter side as it goes downstream with respect to the center line (axis) p of the flow path 4 in the piping direction, or the center line q of the through hole 32 may be configured to be inclined toward the inner diameter side as it goes downstream with respect to the center line (axis) p of the flow path 4 in the piping direction.

[0035] In this embodiment, the through-hole 32 has a circular cross-section, but the cross-sectional shape of the through-hole 32 is not limited to this example. For example, the cross-sectional shape of the through-hole 32 can be elliptical, rectangular, or elongated. When the cross-sectional shape of the through-hole 32 is elliptical, it is desirable that the major axis of the ellipse be in the tangential direction to the inner surface 4a (circular cross-section) of the flow path 4 at the location of the through-hole 32, and the minor axis of the ellipse be in the direction perpendicular to the tangential direction at the location of the through-hole 32, i.e., the radial direction of the inner surface 4a (circular cross-section) of the flow path 4. When the cross-sectional shape of the through-hole 32 is elongated, it is also desirable that the longitudinal direction of the elongated hole be in the tangential direction or circumferential direction to the inner surface 4a (circular cross-section) of the flow path 4 at the location of the through-hole 32. In any case, the number of through-holes 32 and their spacing in the circumferential direction can be freely set.

[0036] In the above embodiment, the cavitation prevention means 30 is constructed by combining the flow channel projection 31 and the through hole 32, but the cavitation prevention means 30 may also be constructed using only the flow channel projection 31 without providing the through hole 32.

[0037] Furthermore, in the above embodiment, the sleeve valve body 13 was moved by the link mechanism 17. However, the sleeve valve body 13 may also be moved by an operating mechanism other than the link mechanism 17, such as a gear mechanism, screw mechanism, plunger mechanism, etc., as long as the relative movement of the sleeve valve body 13 and the cylinder 12 in the axial direction allows the valve seat 14a of the sleeve valve body 13 to move away from the valve casing seat 14b and retract toward the inflow piping 1 side.

[0038] The sleeve valve 10 according to this invention can be used for various purposes, for example, as a flow control valve in water supply systems, a water intake valve in rivers, and various other facilities. Furthermore, the fluid flowing inside is not limited to water, but can be any fluid (liquid).

[0039] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of this invention is defined by the claims and all modifications within the meaning and scope equivalent to the claims are intended. [Explanation of symbols]

[0040] 1 Inlet pipe 1 2 Outlet pipe 2 6 Gap 10 Sleeve valve 11 Valve box 12 cylinders 12c end 13 Sleeve valve body 14a Valve body and seat 14b Valve box valve seat 31 Flow projections 32 Through holes 32a Inner surface

Claims

1. The valve comprises a valve body (11) with both ends open, an inlet pipe (1) connected to one end of the valve body (11) and an outlet pipe (2) connected to the other end, a cylinder (12) disposed within the valve body (11) with the inlet pipe (1) side closed, and a sleeve valve body (13) housed within the cylinder (12) and movable relative to the cylinder (12) along the cylindrical axis, In a sleeve valve in which the valve body seat (14b) provided on the valve body (11) and the valve body seat (14a) provided on the sleeve valve body (13) move toward and toward each other, thereby opening and closing the gap (6) between the end (12c) of the cylinder (12) on the outlet pipe (2) side and the valve body seat (14b), The flow path (4) downstream of the valve body seat (14b) is provided with a flow path projection (31) that protrudes from the inner surface (4a) of the flow path (4) toward the axis (p) of the flow path (4), The valve body seat (14b) is composed of an inclined surface that approaches the axis (p) of the flow path (4) as it moves downstream, and the upstream side surface (31a) of the flow path projection (31) is connected to the inclined surface of the valve body seat (14b), A sleeve valve in which the flow channel projection (31) is provided with a through hole (32) connecting the downstream side surface (31b) and the upstream side surface (31a) of the flow channel projection (31).

2. The sleeve valve according to Claim 1, wherein the upstream side surface (31a) and the inclined surface of the valve body seat (14b) are continuous at the same inclination angle.

3. The sleeve valve according to Claim 1, wherein the angle formed by the downstream side surface (31b) on the downstream and outer diameter side with respect to the axial direction (p) of the flow path (4) is set to be greater than the angle formed by the upstream side surface (31a) on the upstream and outer diameter side with respect to the axial direction (p) of the flow path (4).

4. The sleeve valve according to claim 1, wherein the inner surface (32a) of the through hole (32) has a tapered portion whose cross-section becomes smaller from the upstream side to the downstream side.

5. The sleeve valve according to any one of claims 1 to 4, wherein the center line (q) of the through hole (32) is parallel to the axis (p) of the flow path (4).

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