Rotary valve and wear ring used therein

Abstract

To provide a rotary valve which can suppress the increase in frictional force due to leakage of a liquid material containing fine powder and allows the rotary valve to smoothly operate.SOLUTION: A rotary valve is designed so as to have a gap S between a valve 31 and a valve housing 33 in a cold state in consideration of the difference in a thermal expansion coefficient between a metal valve body 35 / valve housing 33 and a resin wear ring 41A. While a liquid material 5 may leak into the gap S in a cold state, since the leaked liquid material 5 is collected in a spiral groove and an annular groove formed on an outer peripheral surface of the wear ring 41A, the gap S is less likely to be clogged even if the wear ring 41A thermally expands due to a high-temperature liquid material 5 and thereby the gap S gets narrow. Even if the valve 31 continues to operate repeatedly, the frictional resistance between the valve housing 33 and the valve 31 is not excessively generated, and the increase in a viscosity of the liquid material 5 due to frictional heat is suppressed. Thus, the valve 31 can continues to be smoothly rotated.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a rotary valve that is applied to a filling device that fills a container with a liquid material, and a wear ring used therein. [Background technology]

[0002] A filling device is known that fills a container with a fixed amount of liquid by first filling a filling chamber of a cylinder with a liquid stored in a supply tank and then discharging the filled liquid from the cylinder through a filling nozzle into the container (see, for example, Patent Document 1). Some of these filling devices are equipped with a rotary valve that appropriately switches the communication state of the flow path of the liquid, i.e., communication between the supply tank and the cylinder, and communication between the filling nozzle and the cylinder. The rotary valve can reduce frictional resistance of the sliding parts by attaching a resin wear ring. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2008-110803 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the filling device to which the above-mentioned rotary valve is applied, when a high-temperature liquid containing fine powder is filled into a container, a gap is provided between the valve body and the valve housing in consideration of the difference in thermal expansion coefficient between the metal valve housing and the resin wear ring. Here, when the filling device is cold (for example, immediately after a long-term stop for maintenance, etc.), the wear ring has not thermally expanded, so when the filling device is operated, the liquid may leak into the gap between the valve body and the valve housing. Then, the gap becomes smaller due to a rise in temperature, and friction occurs due to the liquid containing fine powder that has leaked into the gap. After that, by repeatedly rotating the valve body, the fine powder contained in the liquid accumulates, and the friction force increases. This causes a problem that the smooth operation of the rotary valve is hindered. In particular, when the fine powder contained in the liquid contains starch, frictional heat generated by friction increases the viscosity of the liquid, further increasing the frictional force, which becomes a problem.

[0005] The present invention has been made in consideration of the above problems, and aims to provide a rotary valve and a wear ring used therein that can suppress the increase in frictional force associated with leakage of liquid and operate smoothly. [Means for solving the problem]

[0006] In order to solve the above problems, the rotary valve according to claim 1 comprises a valve housing having a cylindrical inner circumferential surface, and a valve body having a cylindrical outer circumferential surface that is rotatably inserted into the valve housing, and the relative rotation between the valve housing and the valve body opens and closes a valve housing port formed in the valve housing and a valve body port formed in the valve body to switch the flow path of the liquid, and is characterized in that a recess is formed in the cylindrical inner circumferential surface of the valve housing or the cylindrical outer circumferential surface of the valve body to collect the liquid that leaks into a gap between the valve housing and the valve body. In the rotary valve according to claim 2, at least a part of the recess is a spiral groove. In the rotary valve according to claim 3, at least a part of the recess is an annular groove extending in the circumferential direction of the valve body. In the rotary valve according to claim 4, a predetermined gap is set between the valve housing and the valve body when the valve housing and the valve body are cold, and the gap becomes smaller due to thermal expansion of the valve housing and the valve body. In the rotary valve according to claim 5, the valve body is provided with a wear ring that constitutes the cylindrical outer circumferential surface, and the recess is formed in the wear ring. The wear ring according to claim 6 is characterized in that it is used in the rotary valve according to any one of claims 1 to 5. Effect of the Invention

[0007] The rotary valve and wear ring of the present invention suppress an increase in frictional force caused by leakage of liquid material, enabling smooth operation. [Brief description of the drawings]

[0008] [Figure 1] 1 is a schematic perspective view of a filling device to which a rotary valve according to a first embodiment of the present invention is applied. [Diagram 2] 2 is a schematic cross-sectional view of the filling device shown in FIG. 1 with the rotary valve placed in a first position. [Diagram 3] 2 is a schematic cross-sectional view of the filling device shown in FIG. 1 with the rotary valve disposed in a second position. [Figure 4] FIG. 2 is a schematic front view of a valve body of the rotary valve shown in FIG. [Diagram 5] 5(a) is a front view of the valve body of the rotary valve shown in FIG. 4, (b) is a cross-sectional view taken along line AA shown in FIG. 5(a), and (c) is a cross-sectional view taken along line BB shown in FIG. 5(a). [Figure 6] 6A and 6B are diagrams of the wear ring of the rotary valve shown in FIG. 4, where (a) is a front view and (b) is a cross-sectional view taken along line CC shown in FIG. 6A. [Figure 7]7(a) is a front view showing a wear ring of a rotary valve according to a second embodiment of the present invention, (b) is a cross-sectional view taken along line DD shown in FIG. 7(a), and (c) is a cross-sectional view taken along line EE shown in FIG. 7(a). [Figure 8] 8A and 8B are diagrams showing a wear ring of a rotary valve according to a third embodiment of the present invention, where (a) is a front view and (b) is a cross-sectional view taken along line FF shown in FIG. 8A. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. The configuration of a filling device to which a rotary valve according to a first embodiment of the present invention is applied will be described in detail with reference to Figs. 1 to 6. 1 to 3, the filling device 1 fills a fixed amount of high-temperature liquid 5 (for example, food such as curry) containing fine powder of spices or the like into multiple containers 3 (for example, portion containers), and comprises at least a rotary valve 11A, a filling unit 13, a filling nozzle 15, a supply tank 17, and a control unit 19. The rotary valve 11A and the filling unit 13 are contained in a housing 21.

[0010] The rotary valve 11A is a three-way valve that switches the flow of the liquid material 5 containing fine powder by opening and closing a port (flow path), and includes a valve housing 33 having a cylindrical inner peripheral surface 33a that is integrally provided with the housing 21, and a valve body 31 having a cylindrical outer peripheral surface 31a that is rotatably inserted into the valve housing 33. The rotary valve 11A can be switched by the control unit 19 between a first position (see FIG. 2) in which the supply tank 17 (valve housing port 40a) and the filling unit 13 (valve housing port 40b) communicate with each other, and a second position (see FIG. 3) in which the filling nozzle 15 (valve housing port 40c) and the filling unit 13 (valve housing port 40b) communicate with each other. As described later, when the filling device 1 is cold (for example, immediately after a long stop for maintenance, etc.), a gap S is formed between the valve body 31 and the valve housing 33 (see FIGS. 2 and 3).

[0011] As shown in Figs. 2 to 6, the valve body 31 includes a substantially cylindrical valve body 35 and a wear ring 41A. The valve body 35 is made of a metal such as stainless steel and includes valve body ports 39a, 39b, and 39c that are open in three directions and communicate with each other. The valve body ports 39a, 39b, and 39c are provided at a plurality of locations (three locations in the illustrated example) at predetermined intervals along the axial direction of the valve body 35. The valve body ports 39a, 39b, and 39c are open in three directions at 90° intervals on the same circumference of the valve body 35 (see Fig. 5(b)). The valve body 35 also includes a tip 37. The tip 37 is cylindrical and includes a flange 37a (see Figs. 5(b) and 5(c)) that extends radially outward from the outer circumferential surface of the valve body 35, and is detachably attached to the openings of the valve body ports 39a, 39b, and 39c on the outer circumferential surface of the valve body 35.

[0012] As shown in FIG. 6, the wear ring 41A is a cylindrical body made of resin such as polytetrafluoroethylene (PTFE), and is detachably provided on the outer circumferential surface of the valve body 35. Three engagement holes 43a, 43b, and 43c are formed on the same circumference of the wear ring 41A at 90° intervals so that the wear ring 41A can engage with the tip 37 of the valve body 35, and these engagement holes 43a, 43b, and 43c are arranged in three sets at predetermined intervals along the axial direction of the wear ring 41A. In addition, the wear ring 41A is formed with a slit 45 extending along its axial direction, and the wear ring 41A can be attached to and detached from the valve body 35 by widening the slit 45. Furthermore, the wear ring 41A has three spiral grooves 47a, 47b, and 47c (recesses) formed on its outer circumferential surface, and annular grooves 49 (recesses) formed at both ends of its outer circumferential surface. Each of the spiral grooves 47a, 47b, and 47c connects the three pairs of engagement holes 43a, 43b, and 43c arranged along the axial direction of the wear ring 41A, respectively, and extends so that both ends thereof are connected to the annular groove 49.

[0013] Between the valve body 31 (wear ring 41A) and the valve housing 33, a predetermined gap S is formed when the filling device 1 is cold, taking into account the difference in thermal expansion coefficient between the metal valve body 35 and valve housing 33 (small thermal expansion) and the resin wear ring 41A (large thermal expansion).The dimensions are controlled so that when heated by the high-temperature liquid 5 at normal operating temperatures, thermal expansion results in an appropriate gap that satisfies the required sealing and sliding properties.

[0014] 2 and 3, the valve housing 33 is made of a metal such as stainless steel, and has valve housing ports 40a, 40b, and 40c that open in three directions opposite valve body ports 39a, 39b, and 39c of the valve body 35. The valve housing port 40a communicates with a supply flow path 55 (see below) of the supply tank 17, the valve housing port 40b communicates with a filling chamber 51a (see below) of a cylinder 51 of the filling section 17, and the valve housing port 40c communicates with the filling nozzle 15.

[0015] 2, in the rotary valve 11A, the valve element ports 39a, 39b of the valve element 31 communicate with the valve housing ports 40a, 40b of the valve housing 33, respectively, and the valve element port 39c and the valve housing port 40c are closed, so that the valve housing ports 40a, 40b communicate with each other via the valve element ports 39a, 39b. When the valve element 31 is in the second position shown in FIG. 3, the valve element ports 39a, 39c of the valve element 31 communicate with the valve housing ports 40b, 40c of the valve housing 33, respectively, and the valve element port 39b and the valve housing port 40a are closed, so that the valve housing ports 40b, 40c communicate with each other via the valve element ports 39a, 39c. The rotary valve 11A is connected to a rotary drive source connected to the control unit 19, and the valve element 31 can be selectively moved to the first position or the second position as appropriate by a command signal from the control unit 19.

[0016] The filling unit 13 is for introducing a certain amount of liquid material 5 from the supply tank 17 and supplying the liquid material 5 to the filling nozzle 15, and includes a cylinder 51 and a piston 53. The cylinder 51 is accommodated in the housing 21 and forms a filling chamber 51a into which the liquid material 5 is filled. The filling chamber 51a is connected to the valve housing port 40b of the valve housing 33. The piston 53 is provided reciprocally within the cylinder 51, and is driven by a drive source (not shown) such as a pneumatic cylinder controlled by the control unit 19.

[0017] 1 to 3, the filling nozzle 15 discharges the liquid material 5 toward the container 3, and is connected to the valve housing port 40c of the valve housing 33. For ease of explanation, in the example shown in the figure, the filling nozzle 15 is a single nozzle, but it may be configured so that multiple nozzles are connected to a single valve body port 39c, or may be configured so that multiple nozzles branch out from a single nozzle.

[0018] 2 and 3, the supply tank 17 is for storing high-temperature liquid material 5 containing fine powder, and is provided with a supply flow path 55 for supplying the liquid material 5 to the filling section 13. The supply flow path 55 of the supply tank 17 is connected to the valve housing port 40a of the valve housing 33 of the rotary valve 11A.

[0019] Next, the operation of the filling device 1 to which the rotary valve 11A according to the first embodiment of the present invention is applied will be described. First, the control unit 19 places the rotary valve 11A in a first position (see FIG. 2) to communicate the supply tank 17 with the filling unit 13. Then, the driving source retracts the piston 53, so that the liquid material 5 is filled from the supply tank 17 into the filling chamber 51a of the cylinder 51 through the rotary valve 11A. Then, after a predetermined amount of the liquid material 5 is filled into the filling chamber 51a, the control unit 19 switches the rotary valve 11A to a second position (see FIG. 3) to communicate the filling nozzle 15 with the filling chamber 51a of the cylinder 51. Then, the driving source advances the piston 53, so that the liquid material 5 is discharged from the filling nozzle 15, and a predetermined amount of the liquid material 5 is filled into the container 3. Then, after the liquid material 5 is filled, the piston 53 is retracted to a certain extent, so that the liquid material 5 remaining in the filling nozzle 15 is sucked toward the cylinder 51, and dripping of the filling nozzle 15 is prevented.

[0020] After the liquid material 5 is discharged, the control unit 19 switches the rotary valve 11A from the second position to the first position and moves the piston 53 completely backward, thereby filling the filling chamber 51a with the liquid material 5 from the supply tank 17. Thereafter, the rotary valve 11A is again switched from the first position to the second position and the piston 53 is moved forward, thereby filling a new container 3 with the liquid material 5 via the filling nozzle 15. In this manner, by repeating the above-mentioned operation of the filling device 1, a fixed amount of the liquid material 5 can be successively filled into the containers 3.

[0021] According to the filling device 1 to which the rotary valve 11A according to the first embodiment is applied, the following advantageous effects can be obtained. When the filling device 1 is cold, the gap S between the valve body 31 and the valve housing 33 is large, taking into consideration the difference in thermal expansion between the valve housing 33 and the valve body 35, and the wear ring 41A, and the liquid material 5 may leak into this gap S. At this time, the liquid material 5 that leaks into the gap S is stored in the spiral grooves 47a, 47b, 47c and the annular groove 49 formed on the outer circumferential surface of the wear ring 41A, so that even if the rotary valve 11A is heated by the high-temperature liquid material 5 and the gap S becomes smaller due to the thermal expansion of the wear ring 41A, the gap S is unlikely to become clogged.

[0022] In addition, the spiral grooves 47a, 47b, 47c on the outer peripheral surface of the wear ring 41A move in a manner that scrapes off the liquid material 5 that clogs the gap S as the valve body 31 rotates, making it easier to collect the liquid material 5 that leaks into the spiral grooves 47a, 47b, 47c.

[0023] As a result, even if the valve element 31 of the rotary valve 11A continues to operate repeatedly due to continuous operation of the filling device 1, excessive frictional resistance is not generated between the valve housing 33 and the valve element 31, and an increase in viscosity of the liquid material 5 due to frictional heat is also suppressed. This allows the valve element 31 of the rotary valve 11A to continue to rotate smoothly.

[0024] In the rotary valve 11A according to the first embodiment, the spiral grooves 47a, 47b, and 47c are formed to pass through the engagement holes 43a, 43b, and 43c of the wear ring 41A, but they may not pass through the engagement holes 43a, 43b, and 43c and may be at least one single spiral groove. The spiral groove may be connected to at least one of the engagement holes 43a, 43b, and 43c.

[0025] Next, a filling device 1 according to a second embodiment of the present invention will be described with reference to Fig. 7. Note that the filling device 1 according to this embodiment differs from the filling device 1 according to the first embodiment only in the structure of the wearing, so the same reference numerals are used for similar parts, their description is omitted, and different parts will be described.

[0026] As shown in Fig. 7(a) to Fig. 7(c), the wear ring 41B of the rotary valve 11B of the filling device 1 according to this embodiment includes four annular grooves 61 (recesses) arranged between the three pairs of engagement holes 43a, 43b, and 43c of the wear ring 41B, and four holes 63 formed on the same circumference between the three engagement holes 43a, 43b, and 43c arranged on the same circumference. The bottom of the holes 63 is closed by the valve body 35 to form a recess. The holes 63 may be holes of other shapes such as a triangle, a square, or an ellipse.

[0027] According to the filling device 1 to which the rotary valve 11B according to the second embodiment is applied, the following operational effects can be obtained. Since the wear ring 41B of the rotary valve 11B has annular grooves 61, 49, and holes 63 formed on its outer circumferential surface, the liquid material 5 leaking into the gap S can be scraped off by the holes 63 and collected in the annular grooves 61, 49, and holes 63. As a result, the leaked liquid material 5 is less likely to clog the gap S, and the valve body 31 of the rotary valve 11B can be kept rotating smoothly, similar to the first embodiment.

[0028] Next, a filling device 1 according to a third embodiment of the present invention will be described with reference to Fig. 8. Note that the filling device 1 according to this embodiment differs from the filling device 1 according to the second embodiment only in part of the structure of the wearing ring, so the same reference numerals are used for similar parts, their description is omitted, and only different parts will be described.

[0029] 8(a) and 8(b), the wear ring 41C includes an inclined groove 65 that connects the annular groove 61 and the annular groove 49 with the hole 63, in addition to the configuration of the wear ring 41B of the second embodiment. The inclined groove 65 is inclined with respect to the axial direction of the wear ring 41C, passes through the hole 63, and has both ends communicating with the annular grooves 61 and 49 adjacent to the engagement holes 43a, 43b, and 43c.

[0030] According to the filling device 1 to which the rotary valve 11C according to the third embodiment is applied, the following advantageous effects can be obtained in addition to the advantageous effects of the second embodiment. The inclined groove 65 scrapes off the liquid material 5 leaking into the gap S, and allows the liquid material 5 pooled in the hole 63 to escape to the annular groove 61 and the annular groove 49 side via the inclined groove 65. This makes it difficult for the liquid material 5 to clog the gap S, and similarly to the second embodiment, the valve body 31 of the rotary valve 11C can continue to rotate smoothly.

[0031] In the rotary valves 11A, 11B, 11C according to the first to third embodiments, recesses (spiral grooves 47a, 47b, 47c, annular groove 61, etc.) for storing the liquid material 5 leaked into the gap S are provided on the outer circumferential surfaces of the wear rings 41A, 41B, 41C of the valve body 31, but recesses may be formed on the cylindrical inner circumferential surface 33a of the valve housing 33. In addition, these recesses may be formed on both the cylindrical outer circumferential surface 31a of the valve body 31 and the cylindrical inner circumferential surface 33a of the valve housing 33.

[0032] In the rotary valves 11A, 11B, and 11C according to the first to third embodiments, the recesses (spiral grooves 47a, 47b, 47c, annular groove 61, etc.) formed on the outer peripheral surface of the wear rings 41A, 41B, and 41C of the valve body 31 are continuous grooves, but may also be grooves divided at regular or irregular intervals.

[0033] In the rotary valve 11A according to the first embodiment, the spiral grooves 47a, 47b, 47c may be formed by adding grooves such as vertical grooves extending in the circumferential direction of the wear ring 41A from the spiral grooves 47a, 47b, 47c, or horizontal grooves extending in the axial direction of the wear ring 41A.

[0034] In the rotary valves 11A, 11B, and 11C according to the first to third embodiments and the third embodiment, the number of recesses (spiral grooves 47a, 47b, and 47c, annular groove 61, and the like) may be changed as appropriate. In addition, the annular groove 61 extends in the circumferential direction of the wear rings 41B and 41C, but may be a groove extending in the axial direction of the wear rings 41B and 41C, or may be configured so as to combine the annular groove 61 with a groove extending in the axial direction of the wear rings 41B and 41C. In addition, a groove (recess) may be provided so as to connect adjacent annular grooves 61 to each other.

[0035] In the rotary valves 11A, 11B, and 11C according to the first to third embodiments and the third embodiment, grooves may be provided extending from the engagement holes 43a, 43b, and 43c in the circumferential direction of the wear rings 41A, 41B, and 41C. This allows the liquid material 5 containing fine powder to be stored in the grooves. However, providing such grooves may reduce sealing performance, and the liquid material 5 stored in the grooves may flow into the filling nozzle 15 via the valve housing port 40c. As a result, dripping from the filling nozzle 15 may occur.

[0036] In the rotary valve 11B according to the second embodiment, the wear ring 41B is an integral cylinder, but may be a divided ring, that is, a ring-shaped wear ring in which the cylindrical parts forming the bottoms of the annular groove 61 and the annular groove 49 are removed and only the engagement holes 43a, 43b, 43c and the hole 63 are formed. In this way, when the divided ring-shaped wear ring is attached to the valve body 31, a groove (space) is formed between them, and the liquid material 5 containing fine powder can be stored in this groove.

[0037] In the first to third embodiments, the liquid material 5 is not limited to one containing fine powder, and the effects of the present invention can be expected from any liquid material that has a certain degree of viscosity and has the potential to clog the gap S. The present invention can also be applied to a valve body that is not provided with a wear ring. [Explanation of symbols]

[0038] 5...liquid body, 11A, 11B, 11C...rotary valve, 31...valve body, 31a...cylindrical outer peripheral surface, 33...valve housing, 33a...cylindrical inner peripheral surface, 39a, 39b, 39c...valve body port, 40a, 40b, 40c...valve housing port, 41A, 41B, 41C...wear ring, 47a, 47b, 47c...spiral groove (recess), 49...annular groove (recess), 61...annular groove (recess), 63...hole (recess), 65...inclined groove (recess), S...gap

Claims

1. A rotary valve comprising: a valve housing having a cylindrical inner circumferential surface; and a valve element having a cylindrical outer circumferential surface rotatably inserted into the valve housing, wherein a valve housing port formed in the valve housing and a valve element port formed in the valve element are opened and closed by relative rotation between the valve housing and the valve element to switch a flow path of a liquid material, a recess for collecting liquid leaking into a gap between the valve housing and the valve body, the recess being formed on the cylindrical inner surface of the valve housing or on the cylindrical outer surface of the valve body.

2. 2. The rotary valve according to claim 1, wherein at least a portion of the recess is a spiral groove.

3. 3. The rotary valve according to claim 1, wherein at least a portion of the recess is an annular groove extending in a circumferential direction of the valve body.

4. A predetermined gap is set between the valve housing and the valve body in a cold state, 4. The rotary valve according to claim 1, wherein the gap becomes smaller due to thermal expansion of the valve housing and the valve body.

5. The valve body is provided with a wear ring that constitutes the cylindrical outer circumferential surface, 5. The rotary valve according to claim 1, wherein the recess is formed in the wear ring.

6. A wear ring for use in the rotary valve according to any one of claims 1 to 5.

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