JPH1037851A - Chattering preventive device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent an outer size of a dash pot form being increased due to an arrangement of a chattering preventive valve within a cylinder of the dash pot and prevent a possibility of external leakage of oil caused by arranging the chattering preventive valve. SOLUTION: A chattering preventive valve 30 is assembled into a piston 24 of a dash pot arranged at a check valve. Its plunger 33 is always pushed by a spring 34 to cause holes 36a, 36b to be sight off. When the check valve is closed, the piston 24 is lowered as the check valve is closed, although the plunger 33 is abutted against a front wall 22a of a cylinder and lifted up just before a valve element of the check valve is butted against a valve seat so as to cause holes 36a, 36b to be communicated to each other. Due to this fact, oil below the piston 24 passes through the holes 36a, 36b and flows upwardly to loosen a gradual closing action of the dash pot and to cause a smooth notion of the piston 24 to be carried out and then a chattering action is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chattering prevention device attached to a dashpot attached to a check valve provided, for example, in a water pipe.

[0002]

2. Description of the Related Art In a water pipe or the like, if the pump stops suddenly during water supply due to an unexpected accident such as a power failure, the pressure at the pump outlet side drops suddenly, and the water in the pipe gradually flows backward toward the suction side. Start. In order to prevent this backflow and prevent damage to the pump and the like, a check valve is provided at the outlet side of the pump.

An example of the check valve V will be described with reference to FIGS. 1 to 3. A valve body 2 having an auxiliary valve seat 2a is provided in a valve box 1 via a shaft 3 so as to be swingable. In a state where the pump is operated normally and water flows as shown by an arrow in FIG. 2, the flow causes the valve body 2 and the sub-valve body 2a to swing and open as shown by a chain line in FIG. When the pump stops suddenly and the flow stops, the valve body 2 first comes into contact with the valve seat 5 by its own weight, and then the sub-valve body 2a comes into contact with the valve seat 5a to close the valve. In the case of a large valve, a valve closing counterweight 4 may be provided on the sub-valve element 2a as shown by a chain line in the drawing. At the time of closing the valve, if the sub-valve element 2a suddenly comes into contact with the sub-valve seat 5a, a so-called water hammer phenomenon occurs. This water hammer phenomenon can cause damage to tubes, valves V, and other equipment.

For this reason, in recent years, a dash pot has been attached to the check valve V in order to prevent the water hammer phenomenon. An example of the dashpot D is described in Japanese Patent Publication No. 64-4070, and FIGS.
There are the following. This dashpot D is cylinder 4
0, a piston 41 is provided, and the piston 41 is connected to the shaft 3 via a link 42, and the piston 41 is moved according to the swing of the valve body 1.
The oil (oil) filled in the cylinder 40 is alternately moved to both sides of the piston 41 through the pipe 43,
The sub-valve body 2a is moved by the sub-valve seat 5
a) to loosen sudden contact with a. In the figure, reference numeral 44 denotes a needle valve for adjusting the flow resistance.

In the operation of the dash pot D, if the flow resistance is large, the valve body 2 does not contact the valve seat 5 smoothly and it takes time, and so-called chattering occurs.
On the other hand, if the flow resistance is small, a sufficient gentle closing action cannot be performed.

For this reason, the above publication discloses a technique for preventing the chattering. This technique uses a cylinder 40 of a dashpot D as shown in FIGS.
An anti-chattering device A is provided on the outer surface, and the device A is provided with a piston 46 in a casing 45,
Before the sub-valve element 2a comes into contact with the sub-valve seat 5a, the piston 41 of the device A is pushed down by the piston 41 of the dashpot D as shown by a dashed line in the figure, and the hole 47 in the piston 46 communicates with the hole 48 of the casing 45. Let the hole 4
The oil in the cylinder 40 flows into the upper part of the cylinder 40 via the pipe 49 via the pipes 7 and 48 to loosen the loosening action of the dash pot D, so that the sub-valve 2a smoothly contacts the sub-valve seat 5a. Let it. In the drawing, 50 is a spring for returning the piston 46.

[0007]

The chattering device A described in the above-mentioned official gazette has a cylinder 40 of a dashpot D.
It is attached to the lower outer surface of. For this reason, the size becomes large, and an extra space is required at the time of installation. In addition, since it is exposed to the outside, so-called maintenance such as adjustment and inspection is often required, and therefore,
It must be installed in a direction that facilitates maintenance. Furthermore, since it is installed outside, it is necessary to pay particular attention to the seal so as not to cause oil leakage.
Further, a pipe 49 for returning oil to the upper portion of the cylinder 40 is required, and it is necessary to prevent external leakage of oil in the pipe. In addition, a pipe space is naturally required, and the entire space becomes large.

SUMMARY OF THE INVENTION It is an object of the present invention to prevent the external dimensions from increasing and to eliminate the danger of external leakage of oil.

[0009]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a valve body which is swingably provided in a valve box via a shaft, and the valve body is moved by swinging the valve body. In the above-described check valve that opens and closes a valve by coming into contact with and separating from a seat, the piston in a cylinder of a dash pot attached to the outer surface of the valve box is opened just before the valve body contacts the valve seat, and both sides of the piston are opened. The anti-chattering valve to communicate is provided (claim 1).

With this arrangement, the opening of the anti-chattering valve relaxes the dashpot loosening action before the valve element of the check valve comes into contact with the valve seat, and the valve element is smoothly moved to the valve seat. And no chattering occurs. In addition, since the anti-chattering valve is provided in the cylinder of the dashpot, the dashpot is less likely to break down, there is no need to worry about oil leakage, and the size of the dashpot itself does not change at all.

In the anti-chattering valve, a plunger is provided on the piston so that the piston protrudes toward the valve closing side of the check valve so that the plunger can protrude and retract. A biasing spring is provided, and a hole is formed on both sides of the piston through a sliding surface of the plunger. The plunger always projects by the spring to block the hole, and the valve body May contact the front wall of the cylinder shortly before contacting the valve seat, and may be pushed into the piston against the spring by further movement of the piston to open the hole. 2).

With this arrangement, the anti-chattering valve is operated by the dashpot piston, and the piston itself controls its own movement to prevent chattering.

In the above two inventions, a storage space for the spring is formed in the piston, and this storage space is
The hole formed in the plunger can be configured to communicate with the side surface of the piston from which the plunger projects (claim 3).

With this arrangement, oil is applied to both ends of the plunger in the axial direction at an equal pressure, and the plunger does not move unnecessarily except for contact with the front wall.

Further, the anti-chattering valve is provided separately from the piston and is screwed into a hole passing through both sides of the piston.
A configuration may be provided in which a spring, a communication hole, and a storage space are provided (claim 4).

In this way, if a through hole is formed in the piston of the existing dashpot and the chattering preventing valve is screwed into the hole, the chattering preventing action can be achieved even in the existing dashpot. .

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, a check valve V will be described with reference to FIGS. 1 to 3. As described above, a valve body 2 is swingable through a shaft 3 in a valve box 1 as described above. A sub-valve seat 5 a is formed on the valve body 2, and the sub-valve body 2 a swingable on the shaft 3 comes into contact with and separates from the sub-valve seat 5 a. This sub valve seat 5
The lower end of a connecting rod 20 of a dashpot D described later is connected to a. For this reason, if the pump operates normally and water flows as shown by the arrow in FIG. 2, the flow causes the valve body 2 and the sub-valve body 2a to push up the connecting rod 20 and rise together as shown by the chain line in FIG. . This condition is maintained as long as there is flow.

In this state, when the pump suddenly stops and the flow stops, the valve body 2 swings downward by its own weight and the counterweight 4 and contacts the valve seat 5. On the other hand, since the braking force by the dash pot D acts on the sub-valve 2a,
It swings gradually downward and comes into contact with the auxiliary valve seat 5a. By this operation, the valve seat 5 is gradually closed in two stages, and water hammer is prevented. The number of the sub-valve 2a and the sub-valve seat 5a is arbitrary, and the connecting rod 20 can be connected to the valve 2 without providing all of them. In the figure, reference numeral 6 denotes a bypass pipe with a bypass valve 6a connecting the front and rear of the check valve V.

As shown in FIGS. 1 to 3, the dashpot D has a stand 21 bolted to the upper surface of the valve box 1, and a cylinder 22 is provided on the stand 21. FIG. 4 shows the details, and the connecting rod 20 reaches the inside of the cylinder 22 through the stand 21 via the flange coupling 23a and the bearing 23b. The cylinder 22 includes a front lid (wall) 22a, a middle cylinder 22b, and a bottomed cylinder 22c.
3 parts, bolt them and stand 2
1 and is almost completely filled with oil.

A piston 24 is provided on the connecting rod 20 that has entered the cylinder 22. The piston 24 moves in accordance with the lifting and lowering of the connecting rod 20, that is, the swinging of the sub-valve 2a.
Moves in the cylinder 22. The upper and lower chambers in the cylinder 22 defined by the piston 24 are communicated with each other by a rubber hose 25. As the piston 24 moves, oil in the upper and lower chambers of the cylinder 22 flows in and out through the hose 25. The oil flow resistance is adjusted by adjusting the degree of opening of the angle type needle valve 26. At the inner surface of the upper portion of the middle cylinder 22b of the cylinder 22, there are formed angular grooves 27 that gradually become shallower in the downward direction at appropriate intervals around the groove. When closing the sub-valve body 2a described later, the grooves 27 are formed through the grooves 27. Oil also passes from the lower chamber to the upper chamber, and the sub-valve 2a
Smooth initial operation when closing.

The piston 24 is provided with a check valve 28 and an anti-chattering valve 30. The check valve 28
The ball 28a and the spring 28b are inserted into the through hole 29, and the spring retainer 28c is screwed. When the piston 24 moves upward, the ball 28a is moved downward by oil pressure to open the through hole 29. The oil in the upper chamber is guided to the lower chamber via 29, and the movement of the oil by the rubber hose 25 is assisted, so that the upward swing of the valve body 2 and the sub-valve body 2a is smooth.

The chattering prevention valve 30 is shown in detail in FIGS. 5 and 6. A two-stage through hole 32 is formed in a cylindrical casing 31, and a plunger 33 is slidably inserted into the hole 32. And the plunger 3 is moved by the spring 34.
3 is urged downward, and the spring 34 is retained by a spring retainer 35.

The casing 31 and the plunger 33 are provided with through holes 36a and 36b, respectively.
When the spring 3 is lowered by the spring 34 (FIG. 5), the two holes 36a and 36b are formed in the sliding portion 33a of the plunger 33.
When the plunger 33 rises against the spring 34 (FIG. 6), the sliding portion 33a separates from the opening of the hole 36a, and the two holes 36a, 36b communicate with each other.
b, both sides of the piston 24, ie, the cylinder 22
Upper and lower chambers communicate with each other.

In this embodiment, when the pump normally operates and water flows as shown by the arrow in FIG. 2, the valve body 2 and the sub-valve body 2a are moved by the piston through the connecting rod 20 by the flow. While pushing up 24, both rise as shown by the chain line in FIG. At this time, the check valve 28 is opened to allow the oil to pass therethrough and assist its operation.

On the other hand, the anti-chattering valve 30
b through hole 32 with spring 34 (spring chamber 34a)
And the oil pressures on the upper and lower end surfaces of the plunger 33 become the same, that is, equal pressures, so that the plunger 33 does not move unnecessarily. This condition is maintained as long as the pump is working properly and there is flow.

Next, when the pump is stopped for some reason, first, the valve body 2 has its own weight and the counterweight 4.
Swings downward and comes into contact with the valve seat 5 in a state where the sub-valve seat 5a is open, thereby preventing a water hammer. On the other hand, since the sub-valve 2a is connected to the piston 24 of the dashpot D by the connecting rod 20, the oil flow in the cylinder 22 based on the lowering of the piston 24, that is, the hose from the lower chamber to the upper chamber 25 and square groove 2
7 gradually swings downward while being controlled by the resistance force based on the oil displacement via 7.

That is, the piston 2 of the dashpot D
The position of 4 starts to descend from the top, and the piston 24 moves downward. At this time, the oil on the lower side of the piston 24 has two routes, one for returning to the upper portion of the piston 24 through the needle valve 26 and one for returning to the upper portion of the piston 24 through the square groove 27. The total oil amount is the descending speed of the piston 24. Here, the amount of return from the needle valve 26 is constant (if the pressure is the same), but the depth of the angular groove 27 becomes shallower as the sub-valve 2a approaches the fully closed position, so the amount of return from the angular groove 27 gradually increases. Less,
The descent speed is so-called slow closing which is fast at first but gradually slows down. When the angular groove 27 is further depressed and the angular groove 27 disappears, there is no return from the angular groove 27, and only the needle valve 26 is provided. For this reason,
The size and length of the square groove 27 are determined depending on the use conditions and the like. The opening of the needle valve 26 is also adjusted according to the use conditions.

The sub-valve 2a is positioned before the sub-valve seat 5a,
For example, when the valve is fully closed 5 degrees (the sub valve body 2a is inclined 5 degrees with respect to the vertical), the plunger 33 is moved to the cylinder 22.
As the piston 24 descends, the plunger 33 rises with respect to the piston 24 to communicate with the holes 36a and 36b, as shown in FIG. 6, and the oil passes through the holes 36a and 36b. Flows out from the lower chamber of the cylinder 22 to the upper chamber as indicated by a chain line arrow in the figure. That is, the oil performs both the outflow of the dash pot D's original slow closing action and the outflow of the chattering prevention valve 30.
Therefore, the piston 24 descends smoothly, and the sub-valve 2
a smoothly contacts the auxiliary valve seat 5a, and the check valve V closes. That is, the valve is closed without chattering.

[0029] Again, if the pump works and produces a flow,
Due to the above-mentioned action, the valve bodies 2, 2a are pushed upward by the flow, and the state shown by the chain line in FIG. 2 is obtained. At this time, the piston 24 also rises together via the connecting rod 20, and the plunger 33 separates from the front lid 22a with the operation, and the state shown in FIG. 5 is obtained. At the time of this valve opening, the valve element 2 and the sub-valve element 2a are generally required to open lightly with a flow force,
The return amount of oil from the needle valve 26 and the square groove 27 gradually increases in the opposite direction to that at the time of closing, and separately, the check valve 28 opens to return the oil to the upper part of the piston 24. To encourage. Since the amount of return from the check valve 28 is relatively large, the valve elements 2 and 2a open lightly and quickly, satisfying the requirement.

FIG. 7 shows another embodiment of the anti-chattering valve 30. In this embodiment, the casing 31 is eliminated, and a spring 34, a plunger 33 and the like are incorporated in the piston 24. 33 is retained by the plate 37. The through hole 36 is formed by the hole 36a of the piston 24 and the hole 36b 'of the plate 37, and the oil is fed into the spring chamber 34a via the hole 36b of the plunger 33 described above.

Therefore, as shown in FIG.
When opening 2a (when swinging upward), the plunger 33 is pushed down by the spring 34, and
6a and 36b 'are shut off. And the sub-valve 2a
When the valve is closed (during downward swing), the sub-valve element 2a is
Prior to contact with the piston a, the plunger 33 contacts the front cover 22a of the cylinder 22 and moves upward with respect to the piston 24 as shown by a chain line in accordance with the lowering of the piston 24, similarly to the above-described embodiment, and the holes 36a and 36b Communicates from the lower chamber of the cylinder 22 to the upper chamber to prevent chattering.

In the embodiment, two oil flow passages (holes 36a) of the piston 24 are provided. However, if the closing speed is increased, three or more oil flow passages may be provided or the inner diameter of the flow passage may be increased. . On the other hand, if the speed is to be reduced, it may be reduced to one location or the inner diameter may be reduced. Further, when changing the operation opening of the chattering prevention valve 30 (the position at which the plunger 33 contacts), the screwing position of the casing 31 is changed, or the plunger 33 is replaced with one having a different protruding length. I do.

The anti-chattering valve 30 of this embodiment
Are not only the piston 24 of the dashpot D shown in FIG. 4 and the like, but also the piston 41 of the dashpot D shown in FIG.
It is needless to say that the check valve V may be other than the illustrated one.

[0034]

Since the present invention is constructed as described above and the anti-chattering valve is provided in the cylinder of the dashpot, the external dimensions of the dashpot are not increased, and the outside of the oil based on the attachment of the anti-chattering valve is reduced. There is no fear of leakage.

If the anti-chattering valve is provided separately from the piston, the anti-chattering effect can be obtained only by attaching the anti-chattering valve to the piston of the existing dashpot.

Further, if oil is applied to both ends of the plunger of the chattering preventing valve at an equal pressure, the plunger does not move unnecessarily and the operation is stabilized.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of an example of a check valve with a dashpot.

FIG. 2 is a cutaway front view of a main part of the check valve.

FIG. 3 is a cutaway right side view of a main part of the check valve.

FIG. 4 is a cross-sectional view of one embodiment of a dashpot.

FIG. 5 is an enlarged sectional view of a main part of FIG. 4;

FIG. 6 is an enlarged sectional view of a main part for explaining the operation of the embodiment.

FIG. 7 is an enlarged sectional view of a main part of another embodiment of the anti-chattering valve.

FIG. 8 is a sectional view of a conventional dashpot.

9 is an enlarged sectional view of a main part of FIG. 8;

[Explanation of symbols]

 A anti-chattering device D dash pot V check valve 1 check valve box 2 check valve valve 2a check valve sub-valve 3 valve body swing shaft 4 counterweight 5 check valve valve seat 5a Sub-valve seat of check valve 20 Connecting rod 22 Cylinder 22a Cylinder front wall (front cover) 24 Piston 25 Rubber hose 30 Anti-chattering valve 31 Casing 32 Through hole 33 Plunger 34 Spring 34a Spring storage space 36a, 36b, 36b 'hole

Claims (4)

[Claims] 1. A valve body 2, 2a is swingably provided in a valve box 1 via a shaft 3, and the valve body is swung by a swing of the valve body.
In the check valve which opens and closes the valve by contacting and separating the valve body 5a, the piston is opened to the piston 24 in the cylinder 22 of the dashpot D attached to the outer surface of the valve box 1 just before the valve body contacts the valve seat. 24. An anti-chattering device provided with an anti-chattering valve 30 for communicating both sides. 2. The anti-chattering valve 30 is provided on the piston 24 such that a plunger 33 projecting toward the valve closing side of the check valve V is provided on the piston 24 so that the plunger 33 can come and go. , The plunger 3
3 is provided in the projecting direction, and holes 36a and 36b are formed in both side surfaces of the piston 24 through the sliding surface of the plunger 33. 34, the holes 36a, 36b are shut off, and the valve body comes into contact with the front wall 22a of the cylinder 22 just before the valve body comes into contact with the valve seat. The anti-chattering device according to claim 1, wherein the holes (36a, 36b) are opened by being pushed into the piston (24). 3. A storage space 34a for the spring 34 is formed in the piston 24.
Through the hole 36b formed in the plunger 33,
The chattering prevention device according to claim 2, wherein the plunger (33) communicates with a side surface of the protruding piston (24). 4. The plunger 33, the spring 34, and the communication hole 36a are provided in a casing 31 in which the anti-chattering valve 30 is separate from the piston 24 and is screwed into a hole penetrating through both sides of the piston 24. The anti-chattering device according to claim 2 or 3, wherein the anti-chattering device is provided with a storage space 34a.