non-return valve

Abstract

To provide a check valve which can be arranged in a connection part between a secondary side passage of a pressure reduction valve and a secondary side equipment pipe in one process.SOLUTION: A casing 3 of a check valve 1 forms a cylindrical body of a connection joint D, and so the check valve 1 is integrated with the connection joint D. The connection joint D integrated with the check valve 1 is used for connecting a secondary side passage A" of a pressure reduction valve A and a secondary side equipment pipe B, and so the check valve 1 can be arranged in the connection part between the secondary side passage A" of the pressure reduction valve A and the secondary side equipment pipe B in one process.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a check valve disposed at a connection between pipelines. [Background technology]

[0002] Patent Document 1 discloses a check valve that is disposed at the connection between the secondary passage of a pressure reducing valve that variably adjusts the flow path area at the boundary between the primary passage and the secondary passage in response to the internal pressure of the secondary passage and that is removably inserted into a cylindrical body of a connecting joint that connects the secondary passage of the pressure reducing valve and the secondary equipment piping. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 3536112 Summary of the Invention [Problem to be solved by the invention]

[0004] The check valve of Patent Document 1 has a problem in that when the check valve is disposed at the connection between the secondary passage of the pressure reducing valve and the secondary equipment piping, two steps are required: a step of inserting the check valve into the connecting joint, and a step of disposing the connecting joint with the check valve inserted between the secondary passage of the pressure reducing valve and the secondary equipment piping. The present invention has been made in consideration of the above problems, and has an object to provide a check valve that can be disposed at a connection between pipelines in a single step. [Means for solving the problem]

[0005] In order to solve the above problems, the present invention provides a check valve disposed at a connection between pipelines, the casing of the check valve forming a cylindrical body of a coupling joint that connects the pipelines, the check valve comprising a valve body with an O-ring attached to its outer periphery, and a valve seat formed in the casing and having a seat surface tapered in a funnel shape in a valve closing direction, a valve stem guide and a valve body guide, the valve body guide comprising three or more protrusions spaced apart in the circumferential direction and extending in the valve closing direction from an end face of the valve body on the valve closing direction side. A plurality of notches are formed at intervals in the circumferential direction on the peripheral wall of the O-ring receiving groove in the valve closing direction. The present invention provides a check valve characterized by the above. The casing of the check valve forms the cylindrical body of the connecting joint, so that the check valve is integrated with the connecting joint. Therefore, by connecting the pipelines using the connecting joint, the check valve can be disposed at the connection between the pipelines in a single step. By fitting an O-ring to the outer periphery of the valve disc, the outer periphery of the valve disc can be used as a seal, allowing the valve hole to be enlarged to roughly the same diameter as the valve disc, preventing a reduction in flow rate due to the check valve. By tapering the seating surface of the valve seat into a funnel shape in the valve closing direction, a seal can be maintained even if the valve disc is slightly tilted. It is desirable for the taper angle to be gradual in order to reduce the sensitivity of the seal to the tilt of the valve disc. By guiding the valve stem and the valve body, tilt of the valve body is suppressed, and deterioration of sealing performance is prevented. By arranging the radial outer edges of three or more protrusions facing the circumferential surface of the valve hole with a small gap between them, the valve disc can be guided when the flow rate is low. Since the protrusion extending from the end face of the valve disc in the valve closing direction faces the circumferential surface of the valve hole across a small gap when the flow rate is low, the fluid passage area of ​​the check valve when the flow rate is low is small and the flow speed around the valve disc increases. As a result, abnormal noise may occur when the flow rate is low. By passing the fluid through multiple notches formed at intervals in the circumferential direction on the circumferential side wall of the O-ring housing groove on the valve closing direction side, the fluid passage area of ​​the check valve when the flow rate is low is increased, and the flow speed around the valve disc is reduced, suppressing the generation of abnormal noise when the flow rate is low. In a preferred embodiment of the present invention, the valve body guide has three or more vanes spaced circumferentially and extending radially outward from the valve body, and has a wall connecting the ends of any two adjacent vanes that face the valve seat. The valve body can be guided by arranging the radially outer edges of three or more blades facing the inner peripheral surface of the casing with a small gap between them. At high flow rates, repeated contact between the blades and the casing inner wall can cause abnormal noise. By connecting the ends of any two adjacent blades that face the valve seat with a wall, causing the fluid to collide with the wall to tilt the valve body, and forcibly pressing the blades that are not connected by the wall against the casing inner wall, repeated contact between the blades and the casing inner wall can be suppressed, thereby suppressing the generation of abnormal noise at high flow rates. [Brief description of the drawings]

[0006] [Figure 1] 1 is a cross-sectional view of a check valve according to an embodiment of the present invention, which is disposed at a connection between a secondary passage of a pressure reducing valve and a secondary equipment piping, and shows a cross section of a valve body of the check valve when the valve is closed and when the valve is open. [Diagram 2] FIG. 2 is a partially enlarged view of FIG. [Diagram 3] 1A is a structural diagram of a check valve according to an embodiment of the present invention, in which (a) is a front view, (b) is a side view, (c) is a rear view, and (d) is a cross-sectional view taken along line aa of (a). [Figure 4] 1A and 1B are exploded perspective views of a check valve according to an embodiment of the present invention, in which (a) is a view seen from the upstream side, and (b) is a view seen from the downstream side. [Diagram 5] FIG. 2 is a cross-sectional view of a check valve with a sealing disk. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] A pressure reducing valve according to an embodiment of the present invention, which is disposed at a connection between a secondary passage of the pressure reducing valve and a secondary equipment piping, will be described. In Figures 1 and 2, the left side is called upstream and the right side is called downstream. As shown in FIG. 1, a check valve 1 that protects the pressure reducing valve A from back pressure generated in the secondary equipment is inserted into the connection between the secondary passage A" of the pressure reducing valve A, which variably adjusts the flow path area at the boundary between the primary passage A' and the secondary passage A" in accordance with the internal pressure of the secondary passage A", and the secondary equipment piping B arranged downstream of the pressure reducing valve A, and the end of the secondary passage A" is fastened to the end of the secondary equipment piping B with a quick fastener C. 1 to 4, the check valve 1 includes a cylindrical casing 3 with O-rings 2 disposed on the outer periphery on the upstream side and the outer periphery on the downstream side. A valve seat 4 having an annular seat surface 4a tapered in a funnel shape toward the upstream side, i.e., in the valve closing direction, is formed in the upstream part of the casing 3. On the downstream side of the valve seat 4, an annular stopper 5 consisting of a funnel-shaped slope is formed for a valve body described later. The check valve 1 is provided with a thick disc-shaped valve body 6 facing the valve seat 4. An O-ring 7 is attached to the outer periphery of the upstream part of the valve body 6, i.e., the outer periphery of the valve closing side end. Four blades 8 extend radially outward at intervals in the circumferential direction from the outer periphery of the downstream part of the valve body 6. The radial outer edges of the blades 8 face the inner periphery of the casing 3 with a small gap between them, and the upstream side edges face the stopper 5. As shown in Figures 3 and 4, the upstream ends of two specific adjacent blades 8, i.e., the ends facing the valve seat 4, are connected by a wall 8a, and the radial outer edges are connected by a wall 8b. The other two blades 8 except for the two specific blades 8 are not connected to the other blades 8. Four protrusions 9 extend upstream, i.e., in the valve closing direction, at intervals in the circumferential direction from the upstream end face of the valve body 6, i.e., the end face on the valve closing side. As shown in Fig. 2, the radial outer edge of the projection 9 can face, with a small gap between them, the peripheral surface of a valve hole 10, which is an opening formed in the center of the valve seat 4. As shown in Figs. 3 and 4, a plurality of notches 6a are formed at intervals in the circumferential direction in the upstream peripheral wall of the accommodation groove for the O-ring 7 formed on the outer periphery of the valve-closing end of the valve body 6, i.e., the valve-closing direction peripheral wall. As shown in Figs. 2 to 4, a valve shaft 6' extends downstream from the valve body 6. As shown in Figures 2 and 4, the check valve 1 has a double-ring guide 11 for the valve stem, which is snap-fitted to the downstream end of the casing 3. The double rings are connected by a number of arms. The valve stem 6' is slidably inserted through the inner ring 11a. The check valve 1 is provided with a coil spring 12 disposed between the guide 11 and the valve element 6 to bias the valve element 6 upstream, i.e., in the valve closing direction.

[0008] The operation of the check valve 1 will now be described. During normal operation of the pressure reducing valve A, the valve body 6 receives a biasing force from the fluid flowing from the upstream side to the downstream side and moves downstream against the biasing force of the coil spring 12, the O-ring 7 separates from the valve seat surface 4a, and the check valve 1 is open. When excessive back pressure occurs in the secondary equipment piping B due to a malfunction of the secondary equipment or water hammer caused by the secondary equipment, the valve element 6 receives the biasing force of the coil spring 12 and the back pressure and approaches the valve seat 4, the O-ring 7 abuts against the valve seat surface 4a, and then the vanes 8 abut against the stopper 5, closing the check valve 1. Closing the check valve 1 prevents the back pressure from being applied to the pressure reducing valve A, and prevents damage to the pressure reducing valve A. As can be seen from FIG. 1, the check valve 1 functions as a connecting joint D that connects the secondary passage A" of the pressure reducing valve A to the secondary equipment piping B. That is, the casing 3 of the check valve 1 forms the cylindrical body of the connecting joint D, so that the check valve 1 is integrated with the connecting joint D. Therefore, by connecting the secondary passage A" of the pressure reducing valve A to the secondary equipment piping B using the connecting joint D integrated with the check valve 1, the check valve 1 can be disposed at the connection portion between the secondary passage A" of the pressure reducing valve A and the secondary equipment piping B in one process. In the check valve 1, an O-ring 7 is attached to the outer periphery of the valve disc 6, so that the outer periphery of the valve disc 6 can be used as a seal and the valve hole 10 can be enlarged to approximately the same diameter as the valve disc 6, preventing a reduction in flow rate due to the check valve 1. The seating surface 4a of the valve seat 4 is tapered into a funnel shape in the valve closing direction, so that a seal can be maintained even if the valve 6 is slightly tilted. It is desirable for the taper angle to be gradual in order to reduce the sensitivity of the seal to the tilt of the valve disc 6. In the check valve 1, when the valve is closed, the vanes 8 come into contact with the stopper 5 to restrict excessive movement of the valve body 6 in the closing direction, thereby suppressing excessive deformation of the O-ring 7 and preventing damage to the O-ring 7. In the check valve 1, the radial outer edges of the vanes 8 face the inner surface of the casing 3 with a small gap between them to guide the valve element 6, and the valve shaft 6' is guided by the valve shaft 6 being slidably inserted into the inner ring 11a. This suppresses inclination of the valve element 6 regardless of the flow rate, and prevents deterioration of the sealing performance between the O-ring 7 and the valve seat surface 4a. In the check valve 1, the radial outer edge of the protrusion 9 faces the peripheral surface of the valve hole 10 with a small gap between them, thereby guiding the valve body 6 at low flow rates and suppressing tilt of the valve body 6, thereby preventing deterioration of the sealing performance between the O-ring 7 and the valve seat surface 4a. Since the protrusion 9 extending from the valve closing direction end face of the valve body 6 in the valve closing direction faces the peripheral surface of the valve hole 10 across a small gap when the flow rate is low, the fluid passing area of ​​the check valve 1 when the flow rate is low is small and the flow speed around the valve body 6 increases. As a result, abnormal noise may occur when the flow rate is low. By forming multiple notches 6a at intervals in the circumferential direction on the peripheral side wall on the valve closing direction side of the O-ring 7 housing groove formed in the valve body 6 and flowing the fluid through the notches 6a, the fluid passing area of ​​the check valve 1 when the flow rate is low is increased and the flow speed around the valve body is reduced, thereby suppressing the occurrence of abnormal noise when the flow rate is constant. At high flow rates, abnormal noise may occur due to repeated contact between the blades 8 and the inner peripheral wall of the casing 3. The ends of any two adjacent blades 8 that face the valve seat 4 are connected by a wall 8a, and the valve body 6 is tilted by causing the fluid to collide with the wall 8a, forcing the blades 8 that are not connected by the wall to be pressed against the inner peripheral wall of the casing 3, thereby suppressing repeated contact between the blades 8 and the inner peripheral wall of the casing 3 and suppressing the generation of abnormal noise at high flow rates.

[0009] The upstream ends of three particular adjacent blades 8 may be connected by a wall 8a. The number of blades 8 and the number of protrusions 9 are not limited to those described in the above embodiment. As shown in FIG. 5, a sealing disk 13 may be attached to the end face of the valve body 6 on the valve closing direction side instead of the O-ring. The check valve according to the above embodiment can be disposed not only at the connection between the secondary passage of the pressure reducing valve and the secondary equipment piping, but also at a wide range of connection between pipelines. [Industrial Applicability]

[0010] The present invention can be widely used in check valves disposed at connections between pipelines. [Explanation of symbols]

[0011] A Pressure Reducing Valve A' Temporary side passage A” Secondary passage B Secondary side equipment piping C Quick Fastener D Connection joint 1. Check valve 2 O-rings 3. Casing 4 Valve seat 4a Valve seat surface 5 Stopper 6 Valve body 6a Notch 6' valve stem 7 O-ring 8. Feather 8a wall 9 protrusions 10 valve hole 11 Guide 11a Inner Ring 12 Coil spring 13 Sealing disc

Claims

1. a valve seat formed in the casing and having a seat surface tapered into a funnel shape in the valve closing direction; a valve stem guide and a valve seat guide, the valve seat guide having three or more protrusions spaced circumferentially from the valve closing direction end face of the valve seat, and a plurality of notches spaced circumferentially in the valve closing direction peripheral wall of the O-ring accommodating groove.

2. A check valve as described in claim 1, characterized in that the guide of the valve body has three or more vanes extending radially outward from the valve body at circumferential intervals, and has a wall connecting the ends facing the valve seats of any two adjacent vanes.

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