JPH07332515A - Check valve with slow closing mechanism - Google Patents

Abstract

PURPOSE:To perform the action in a manner wherein when a main valve element is closed, an auxiliary valve element with an auxiliary valve hole left as opened moves to follow the main valve element, and after the main valve element fully closes a main valve hole, the auxiliary valve element is closed in no relation to moving the main valve element to close the auxiliary valve hole, in a check valve with slow closing mechanism performing action of closing the auxiliary valve hole after the main valve hole is closed. CONSTITUTION:A base part of the first arm 41, provided in a main valve element 4, is open/close swivelably mounted on a shaft body 3, and a base part of the second arm 61, provided in an auxiliary valve element 6, is fixed to this shaft body 3. A slow closing mechanism 7 for relaxing a closing action speed of the auxiliary valve element 6 is connected to the shaft body 3. A rear pressing fixture 9, formed of a bar, is fixed to the first arm, to ensure a moving margin S, when opened/closed the auxiliary valve element 6, between this rear pressing fixture 9 and the second arm 61.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a check valve having a slow closing function for preventing a water hammer phenomenon when the valve is closed.

[0002]

2. Description of the Related Art A conventional check valve with a slowly closing mechanism of this type will be described with reference to FIGS. In this check valve, a valve box 1 forms a fluid inlet 11, a fluid outlet 12, a main valve hole 2, a valve chamber 13 and the like, and a space 14 is formed on a side portion of a fluid passage formed by these. Has been done. The shaft body 3 rotatably supported by the bearings 15, 15 of the valve box 1 is arranged in the space 14. Main valve hole 2
A pair of first arms 41, 41 parallel to the back surface of the main valve body 4 for opening and closing the valve are fixed.
Bushings 42, 42 fixed to the bases of 1, 41 are fitted and attached to the shaft body 3 so as to be openable and closable.
The main valve body 4 is provided with a sub valve hole 5 having an opening area smaller than that of the main valve hole 2. A second arm 61 is fixed to the back surface of the sub valve body 6 for opening and closing the sub valve hole 5, and a bush 62 fixed to the base of the second arm 61 is fitted to the shaft body 3. Moreover, the bush 62 and the shaft 3
As shown in FIG. 8, a key 63 is interposed between and. Therefore, the base portion of the second arm 61 is fixed to the shaft body 3 via the bush 62.

A loose closing mechanism 7 which is, for example, a dashpot is connected to one end of the shaft body 3 protruding from the valve box 1. The gradual closing mechanism 7 in the illustrated example has a function of absorbing the load in the pushing direction applied to the rod 72 which can be retracted from the outer cylinder 71 and easing the pushing speed. One end of the shaft body 3 is connected to the rod 72 of No. 7 via a connecting tool 73, a link 74 and the like. A weight 8 is provided on the other end of the shaft 3 protruding from the valve box 1, and a load commensurate with the weight of the weight 8 is constantly applied to the shaft 3. Therefore, the shaft body 3 is constantly urged in the direction of closing the sub valve body 6 by the load commensurate with the weight of the weight 8.

In such a conventional check valve with a slowly closing mechanism, when the fluid is flowing from the fluid inlet 11 to the fluid outlet 12, a differential pressure generated on both sides of the main valve body 4 is not shown. Thus, the main valve body 4 is opened (the opening direction is indicated by the arrow M) and is kept in the open position. Further, the sub-valve body 6 is pushed by the main valve body 4 in the direction along the flow direction of the fluid and follows, and accordingly the shaft body 3 rotates following the sub-valve body 6 against the weight of the weight 8. To do.

When the flow of the fluid from the fluid inlet 11 to the fluid outlet 12 is stopped, the main valve body 4 which has been kept in the open position until now is closed due to its own weight or the differential pressure generated before and after the main valve body 4. , The main valve hole 2 is closed as shown in FIG. In addition, since the closing speed of the sub valve body 6 becomes slower than that of the main valve body 4 due to the action of the slowly closing mechanism 7, the main valve body 4 keeps a certain time delay after closing the main valve hole 2. To close the sub valve hole 5.
When such an operation is performed, even after the main valve body 4 closes the main valve hole 2, the fluid flows through the sub valve hole 5 until the sub valve body 6 closes the sub valve hole 5. Since it circulates before and after, the occurrence of the water hammer phenomenon at the time of check valve operation is prevented.

However, in the above-described conventional check valve with a slow-closing mechanism, when the sub-valve body 6 is closed, the sub-valve body 6 continues to receive the closing motion suppressing action by the slow-closing mechanism 7, and the main valve hole 2 When fully opened, the back pressure of the fluid does not act in the direction of closing the sub valve body 6. Therefore, unless the sub valve body 6 is constantly urged in the closing direction by the weight of the weight 8, it is difficult to close the sub valve body 6. Therefore, a weight 8 is provided at the other end of the shaft body 3, and the weight of the weight 8 constantly urges the sub valve body 6 in the closing direction. Therefore, in the conventional check valve with the gradual closing mechanism, the weight 8 serves to assist the closing movement of the sub valve body 6 to completely close the sub valve hole 5, and the weight 8 is omitted. Therefore, it becomes difficult to close the sub valve body 6.

[0007]

However, the weight 8
By adopting a configuration that assists the closing movement of the sub valve body 6 by means of the check valve with the slowly closing mechanism interposed in the conduit having a large diameter, the weight 8 must be increased, which is structurally preferable. There will be nothing. In addition, regardless of the size of the pipe, the weight of the weight 8 always biases the sub valve body 6 in the closing direction.
This also diminishes the significance of adopting the slow closing mechanism 7 that exerts the action of reducing the closing speed of the sub valve body 6.

The present invention has been made in view of the above circumstances. When the main valve body is closed, the sub valve body follows the main valve body with the sub valve hole open, and the main valve body is the main valve body. The function of the slow-closing mechanism may be impaired by taking measures such that after the valve hole is fully closed, the sub-valve closes regardless of the movement of the main valve to close the sub-valve. In addition, the sub-valve element operates normally without using the weight for normally urging the sub-valve element in the closing direction, and the occurrence of the water hammer phenomenon during the operation of the check valve is ensured. An object of the present invention is to provide a check valve with a slowly closing mechanism that can be prevented.

[0009]

A check valve with a slowly closing mechanism according to the present invention is a main valve for opening and closing the main valve hole on a shaft body rotatably provided in a valve box having a main valve hole. The base portion of the first arm provided on the valve body is attached so as to swing open and close, and the base portion of the second arm provided on the sub valve body for opening and closing the sub valve hole provided on the main valve body is In a check valve with a slowly closing mechanism, which is fixed and has a slowly closing mechanism for relaxing the closing speed of the auxiliary valve element connected to the shaft body, a check valve with a slowly closing mechanism is provided for the first arm, with respect to the auxiliary valve hole of the auxiliary valve element. A pusher for allowing the opening / closing operation and for pushing the auxiliary valve element to follow the auxiliary valve element in the middle of the closing operation of the main valve element is fixed.

[0010]

According to the above construction, when the main valve body is opened, the sub valve body is pushed by the main valve body and follows. At the time when the main valve body starts to close from the open position, the closing speed of the sub-valve body is relaxed by the slow closing mechanism, so the closing speed of the main valve body is faster than that of the sub-valve body. The sub valve hole provided in the main valve body opens. Then, when the main valve body is closed to some extent, the backing tool starts pushing the sub valve body. In this way, the sub-valve pushed by the back-pressing device follows the main valve, but at this stage the sub-valve hole provided in the main valve remains open. Further, at this stage, the effect of the action of the slow closing mechanism extends not only to the sub valve body but also to the main valve body. When the main valve body continues to close and completely closes the main valve hole, the boosting of the sub-valve body by the back-pressing tool ends, after which the sub-valve body slowly closes due to its own weight or the differential pressure between the front and rear. Closes while receiving the action of the mechanism to reduce the closing speed,
Close the sub valve hole.

[0011]

1 is a vertical longitudinal sectional view of a check valve with a slowly closing mechanism according to an embodiment of the present invention, and FIG. 2 is a vertical transverse sectional view of the same check valve. In the check valve with the slowly closing mechanism of the illustrated embodiment,
A difference from the conventional check valve with a slow-closing mechanism described in FIGS. 6 to 8 is that the weight 8 provided in the conventional check valve with a slow-closing mechanism is omitted and a pair of parallel valves are provided. A pusher 9 having a straight bar between the first arms 41, 41.
Is laterally fixed and a gap is formed between the pusher 9 and the second arm 61, and this gap is used as a movement allowance S when the sub valve body 6 is opened and closed. . Since other matters are completely the same as those of the conventional check valve with the slow-closing mechanism described in FIGS. 6 to 8, the same parts are denoted by the same reference numerals and detailed description of the configuration is omitted.

Next, the operation of the check valve with the slowly closing mechanism according to the embodiment will be described.

When the fluid is flowing from the fluid inlet 11 toward the fluid outlet 12, the main valve body 4 opens as shown in FIG. 3 due to the differential pressure generated on both sides of the main valve body 4 (the opening direction is indicated by an arrow M). ) And held in the open position. In this way, when the main valve body 4 opens, the sub valve body 6 is pushed by the main valve body 4 and follows. Then, at the open position of the main valve body 6, the sub-valve body 6 closes the sub-valve hole 5 provided in the main valve body 4 by its own weight. Further, the backing tool 9 is separated from the second arm 61.

When the flow of fluid from the fluid inlet 11 to the fluid outlet 12 is stopped, the main valve body 4 which has been kept in the open position until now is closed due to its own weight or the differential pressure generated before and after the main valve body 4. Start. At the time point when the main valve body 4 starts to close from the open position, the closing operation speed of the sub valve body 6 is relaxed by the slow closing mechanism 7, so that the closing operation speed of the main valve body 4 is lower than that of the sub valve body 6. Is also fast. Therefore, the sub valve hole 5 provided in the main valve body 4 is opened. Further, when the main valve body 4 is closed to some extent, the backing tool 9 contacts the second arm 61. FIG. 4 shows the state when the back-pressing tool 9 hits the second arm 61. When the main valve body 4 continues to be closed further, after the back-pressing tool 9 hits the second arm 61, the back-pressing tool 9 pushes the second arm 61 to back-press the sub-valve body 6. Therefore, the sub valve body 6 follows the main valve body 4 while keeping the sub valve hole 5 open. When the sub valve body 6 is pushed backward, the effect of the action of the slow closing mechanism 7 affects not only the sub valve body 6 but also the main valve body 4. The main valve body 4 continues to close, and as shown in FIG.
When is completely closed, the pushing by the pushing device 9 is completed. From this point onward, the sub valve body 6 is slowly closed while the sub valve body 6 is subjected to the action of reducing the closing speed by the slow closing mechanism 7 due to its own weight or the differential pressure between the front and rear, and the sub valve hole 5 is closed. It becomes a state.

In this embodiment, the rear pusher 9 is operated by the second arm 61 at a stage where the main valve body 4 is closing.
Since the auxiliary valve body 6 is pushed via the auxiliary valve body 6, the operation of the auxiliary valve body 6 is assisted thereby. However, the boosting by the booster 9 ends when the main valve body 4 closes the main valve hole 2, and thereafter the sub-valve body 6 is operated by the slow closing mechanism 7 and the main valve body 4 operates. Since they are closed independently of each other, the function of the slow closing mechanism 7 is not impaired.

In this embodiment, the rear pushing device 9 is constructed to push the second arm backward, but it is also possible to directly push the sub valve body 6 by the rear pushing device 9. In addition, the backing device 9 serving as the movement allowance S of the sub valve body 6
By increasing or decreasing the size of the gap between the second arm 61 and the second arm 61, a time delay from the closing of the main valve hole 2 by the main valve body 4 to the closing of the sub valve hole 5 by the sub valve body 6 is delayed. Can be adjusted. Therefore, in order not to impair the loosely closing function, it is desirable to secure the movement allowance S of a sufficient width by widening the gap to some extent.

[0017]

According to the present invention, a backing member is fixed to the first arm for opening and closing the main valve body around the shaft body, and the auxiliary valve is in the middle of the closing operation of the main valve body. Since the body is pushed backward by the pushing device, the auxiliary valve body is forcibly moved following the main valve body when the main valve body is closed. As a result, the effect that the operation of the sub valve body can be normally performed without providing the weight as described in the conventional example is obtained.

Furthermore, since the above-mentioned pusher is fixed to the first arm so as to allow the sub-valve body to open and close the sub-valve hole provided in the main valve body, the back-presser pushes the sub-valve body. However, after the main valve body closes the main valve hole, the sub-valve body slowly closes the sub-valve hole while being acted on by the slow-closing mechanism with a certain time delay. Is not impaired, and the water hammer phenomenon does not occur during operation of the check valve.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a check valve with a slowly closing mechanism according to an embodiment of the present invention.

FIG. 2 is a vertical cross-sectional view of a check valve with a slowly closing mechanism according to an embodiment of the present invention.

FIG. 3 is a vertical cross-sectional view showing a state in which the main valve body is opened to the open position in the check valve with the slowly closing mechanism according to the embodiment of the present invention.

FIG. 4 is a vertical cross-sectional view showing a state of the check valve with the slowly closing mechanism according to the embodiment of the present invention at a time point when the back-pressing tool hits the second arm.

FIG. 5 is a vertical cross-sectional view showing a state at the time when the main valve body closes the main valve hole in the check valve with the slowly closing mechanism according to the embodiment of the present invention.

FIG. 6 is a vertical cross-sectional view of a conventional check valve with a slowly closing mechanism.

FIG. 7 is a vertical cross-sectional view of a conventional check valve with a slowly closing mechanism.

8 is an enlarged sectional view taken along the line AA of FIG.

[Explanation of symbols]

 1 Valve Box 2 Main Valve Hole 3 Shaft Body 4 Main Valve Body 5 Sub-Valve Hole 6 Sub-Valve Body 7 Slow Closing Mechanism 9 Booster 41 First Arm 61 Second Arm

Claims (1)

[Claims] 1. A base portion of a first arm provided on a main valve body for opening and closing the main valve hole is swingably openable and closable on a shaft body rotatably provided in a valve box having a main valve hole. Is fixed to the base of a second arm provided on the sub valve body for opening and closing the sub valve hole provided on the main valve body,
In the check valve with the slow-closing mechanism, in which the slow-closing mechanism for reducing the closing operation speed of the sub-valve is connected to the shaft body, in the check valve with the slow-closing mechanism, the first arm is configured to open and close the sub-valve of the sub-valve. A check valve with a slowly closing mechanism, characterized in that a pusher for pushing the sub-valve to follow the sub-valve in the middle of allowing and allowing the main valve to close is fixed. .