KR0164645B1 - Water hammer arrestor - Google Patents

Abstract

The present invention proposes a water hammer of a novel configuration.

Conventional water hammer prevents shock absorption due to water hammer by diaphragm or airbag which expands and contracts itself, and the shock absorption effect itself is not only low but also the shock absorption effect varies depending on the pressure state in the pipe and the material deterioration is severe. There was.

In the present invention, the airbag is configured in the form of a corrugated box so that the function can be performed without depending on the material, and the pressure chamber is divided into two spaces connected to the orifice hole to achieve excellent water hammer prevention effect regardless of the pressure change in the pipe. It was made.

Description

Water hammer

1 is a cross-sectional view showing the configuration of a conventional water hammer.

Figure 2 is a cross-sectional view showing the configuration of the applicant's first application water hammer.

3 is a cross-sectional view showing the configuration of a water hammer according to the present invention.

4 and 5 are cross-sectional views showing the operation of the water hammer of the present invention, respectively.

* Explanation of symbols for main parts of the drawings

1: (invention) water hammer protector 2: (body of water hammer)

4: limiting plate 5: orifice hole

P: Piping C: Pressure chamber

C1: first space C2: second space

The present invention relates to a vertical preventer that prevents noise and vibration caused by water hammer in a pipeline.

If the flow resistance changes during the flow of the fluid, the pressure of the fluid changes. In the case of a gas, which is a compressible fluid, the change in flow resistance is merely a change in pressure, but in the case of a liquid, which is an incompressible fluid, the head itself changes. For example, the flow of liquid into a narrow passage from a wide passage is the head, ie, the liquid level, which is generally referred to as a hydraulic jump phenomenon.

In the case where the liquid is supplied in a limited cross section such as a pipe, the problem of the change of the flow path resistance becomes more serious. For example, in the case of water pipes, when the valve is blocked during the flow of water, the rapid change in flow resistance cannot absorb water, which is an incompressible fluid, so that a large shock wave is formed, thereby generating high noise and vibration. The occurrence of shock waves in the liquid pipe is called water hammer in particular. This water hammer problem is somewhat less for rotary valves where the valve is slowly opened with screws, but for the sake of ease of use in recent years, it has become more serious as the rotary valve is converted to a one-touch valve. In addition, damage to pipes, valves, and pumps can occur. In addition to the flow of the liquid in the limited conduit, if the rapid development of the valve, etc., the liquid is rapidly boiled by the pressure drop to generate bubbles in the liquid and cause cavitation (cavitation).

In order to prevent such a water hammer phenomenon, a water hammer as shown in FIG. 1 is generally used.

In FIG. 1, the body B of the water hammer preventer W 'connected to the pipe P has an diaphragm D made of elastic material such as rubber supported between the upper and lower bodies B1 and B2. It is a kind of pressure chamber by injecting a gas such as air or an inert gas, which is a compressive fluid, into a space between the upper body B1 and the diaphragm D through a nipple (N): ).

Such a water hammer prevents the shock wave generated by the valve V being cut off rapidly while the liquid flows in the pipe P, and the diaphragm D is compressed in a dotted line to prevent the occurrence of water hammer. .

That is, the compressor body of the pressure chamber formed between the upper body B1 and the diaphragm D buffers the pressure change in the pipe P to prevent the occurrence of noise and vibration, and prevents the pipe P, the valve V, or the like. To prevent damage to the pump.

However, such a conventional water hammer (W ') is limited to the area of the diagram (D) in which the pressure change is transmitted to the diameter of the body (B) is not possible to quickly absorb a large shock wave to prevent water hammer There was not a big problem. In addition, both the formation of the airbag and the absorption of the shock wave depend only on the diaphragm (D), and since the outer end of the diaphragm is always supported between the upper and lower bodies (B1, B2) in a high tension state, the upper and lower bodies (B1, B2) There is a problem in that the service life is not long, such as the coupling between the very difficult and the diaphragm (D) is easily aged and deteriorated due to fatigue or the like, and thus the function cannot be achieved.

On the other hand, in the conventional water hammer (W ') is introduced into the body (B) of the foreign matter generated in the pipe (P) as it is to be settled inside of it to interfere with the operation of the water hammer (W') to further extend its service life. There was also a problem of shortening.

Accordingly, the cause of the present invention has been filed in Utility Model Registration Application No. 94-29737 by devising a water hammer as shown in FIG.

In FIG. 2, the body B of the water hammer preventer W connected to one side of the pipe P is provided with an air bag A having a closed curved surface in the form of a sphere or a baldder. It is supported by the nipple N and at the same time a gas of a predetermined pressure is filled.

The water hammer preventer W of this configuration has a much higher pressure transfer area than the water hammer of FIG. 1, and changes its elasticity as well as its own shape and absorbs shock waves from the pipe P. Effective water hammering prevention effect.

However, since the airbag A is supported only by the nipples N, the water stopper W having such a configuration is important to seal the coupling portion with the nipples N. Since the coupling portion is easily deteriorated, the compressor body leaks during long-term use. There is a concern.

In addition, the water hammer preventers W and W 'of FIG. 1 and FIG. 2 are made to apply constant back pressure to the diaphragm D or the airbag A by a compressor body. However, the shock absorbing force provided by this compressor body is inversely proportional to the total volume of the compressor body, that is, the volume of the pressure chamber, by Boyle's law. Accordingly, when the volume of the pressure chamber is large, the shock absorbing power is high, but when the volume is small, the shock absorbing power is small. Therefore, when the pressure in the pipe P is severe due to pulsation or frequent opening and closing of the pipe, the shock absorbing effect is not constant, and the fluid in the pipe P, such as the low-level pipe of a building with a water tank on a high floor, is not constant. If the head is high, the diaphragm (D) or the airbag (A) is excessively pressed into the contracted state of the pressure chamber, so that the proper water hammering prevention function cannot be exhibited.

In addition, in the conventional water hammer arresters W and W ', the surface area of the interface between the fluid and the compressor body, that is, the interface of the pressure chamber is enlarged and reduced in accordance with the shock absorption. That is, the diaphragm (D) or the airbag (A) itself repeats the expansion and contraction, so the material of its own must be composed of elastic, durable, tough and very expensive and stable expensive material. For this reason, periodic checks and replacements are required.

In addition, the conventional water hammer preventer (W, W ') mainly absorbs the shock wave and lacks the function of returning the fluid to the pipe (P), when a large shock wave is generated, the continuity in the pipe (P) of the incompressible fluid is broken There was also the problem of causing excessive stress or corrosion in the pipe P by causing local reinforcement or strain.

In view of the various problems of the related art, an object of the present invention is excellent in preventing water hammer in a normal state, and can always function regardless of pressure change in a pipe, and it is stable for a long time because excessive stress is not applied to a material. It is to provide a water hammer to guarantee the performance.

One water hammer according to the present invention to achieve the above object is characterized in that the airbag is configured in the form of bellows (bellows).

According to this configuration, even if the inner space of the airbag is inflated and contracted to absorb the shock wave, the change of the internal volume is mainly performed by the geometric deformation that the corrugated box is folded and unfolded, so the airbag material itself is hardly stressed by the expansion and contraction. Will not. As a result, the airbag maintains stable characteristics for a long time without deterioration.

Another water hammer is to achieve the object of the present invention is characterized in that the restriction plate is provided with an orifice (orifice) hole in the middle of the pressure chamber.

According to this configuration, when the airbag is inflated, the compressor body on the airbag side exits to the opposite side through the narrow orifice hole, increases the back pressure, and gradually decreases the shock absorbing effect. In addition, the limiting plate restricts the axial expansion of the airbag, so that even if the pressure in the pipe is excessively high, it leaves room for absorbing the impact of the water hammer. Therefore, the water hammering prevention effect can be achieved regardless of the pressure change in the pipe. In addition, it is possible to provide sufficient elastic restoring force to return the fluid to the pipe side in the final stage of the shock absorption.

The first feature and the second feature of the present invention have a greater effect when used in combination with each other, and the specific features and advantages will be described with reference to the preferred embodiment with reference to the accompanying drawings.

In FIG. 3, the water hammer preventing device 1 according to the present invention is installed at one side of the pipe P. Approximately one side of the cylindrical body 2 is blocked by an end cap 2a and the other side is a neck. It communicates with the pipe P through (neck: 2b) and is coupled to the pipe P by a flange 2c around it. V is a valve of the pipe P.

Nipple (nipple) (7) is installed on the end cap (2a) through which inert gas such as air or nitrogen is injected at a predetermined pressure to form a pressure chamber (C).

In the neck 2b, an air bag 3 formed in the shape of a corrugation box by an elastic material such as rubber is provided toward the inside of the pressure chamber C. In the illustrated embodiment, a strainer 6, which prevents foreign matter from entering the body 1 from the pipe P, is configured in the form of a cup and is fitted with the neck 2b, thereby providing an airbag (between). It is configured to engage and support one end of 3).

On the other hand, the pressure chamber C in the body 1 is provided with a limiting plate 4 having an orifice hole 5 in the middle thereof, so that the pressure chamber C is provided with the first space C1 on the airbag side and its opposite side. It is divided into 2nd space C2 of. The orifice hole 5 of the limiting plate 4 is in the form of a plate hole extending from the first space C1 to the second space C2 side, so that the second space (from the first space C1) The movement of the compressor body to C2) is restricted.

Here, the fluid communicated in the pipe P is filled in the inside of the airbag 3 at the pressure, and the outside is supported by the pressure of the compressor body in the pressure chamber C. As shown in FIG. In other words, unlike the airbag A of FIG. 2 of the airbag 3 in this embodiment, it will be proper to be called a water bag because a fluid other than the compressor body is filled therein.

However, in the case of realizing only the first feature by the airbag 3 in the form of a corrugated box without the second feature of the present invention, such as the limiting plate 4, the airbag 3 is attached to the nipple 7 as shown in FIG. It may be configured to be combined to fill a compressor body therein to form a pressure chamber. That is, in the present invention, the name of the airbag 3 is meant as an interface for separating the fluid and the pressure chamber C, and there is no limitation whether the fluid or the compressor is filled therein.

On the other hand, the limiting plate 4 itself also acts as a stopper to limit the axial expansion of the airbag 93, which restricts the airbag 3 in the form of a corrugated box from further geometrical deformation. This prevents excessive stress from being applied. After the airbag 3 is in contact with the limiting plate 4, the increase in the fluid pressure is accommodated in the radial expansion of the airbag 3 itself, which, together with the opiris hole 5, has a shock absorbing effect as described below. It will be further improved.

Such operation of the water hammer 1 of the present invention will be described with reference to FIGS. 4 and 5. FIG.

In the airbag 3 of the water hammer prevention device 1 in the state shown in FIG. 3, when water hammer occurs in the pipe P, and a shock wave is transmitted to the inside thereof, the corrugation spreads upward in the drawing as shown in FIG. As the everback 3 expands, the volume of the first space C1 of the pressure chamber C is reduced so that the pressure in the first space C1 increases, and the compressor body in the first space C1 is orifice. It moves to the second space C2 through the hole 5.

At this time, since the orifice hole 5 restricts the movement of the compressor body, the compressor body in the first space C1 gradually moves to the second space C2, and the pressure in the first space C1 gradually decreases from the increased state. do.

That is, if the conventional water hammer prevents shock waves caused by water hammer by providing one air spring by the pressure chamber, the present invention uses two air springs of the first space C1 and the second space C2. In addition, since the shock wave is buffered and absorbed by the orifice hole 5, it is possible to absorb more smoothly.

When the airbag 3 is further inflated and its tip contacts the limiting plate 4 as shown in Fig. 5, the orifice hole 5 is blocked. Then, the compressor body of the first space C1 is no longer allowed to escape to the second space C2, thereby increasing the pressure of the first space C1. The further increase in pressure in the airbag 3 is then accommodated by the expansion of the airbag 3 material itself.

In this way, after the airbag 3 blocks the orifice hole 5, the first space C1 provides a larger elastic air spring. It can be seen that the water hammer 1 of the present invention operates on the following principle.

That is, when a shock wave is generated by the water hammer phenomenon, first, the shock wave is absorbed by a soft two-stage air spring formed by the two spaces C1 and C2 through the orifice hole 5, and when the shock wave absorption finishes, the sealed first The rigid air spring by the space C1 provides an elastic reaction force against the shock wave.

Accordingly, the shock wave caused by the water hammer is absorbed smoothly, and almost no noise and vibration are generated. In addition, in the finishing stage of the shock absorption, the fluid sheared by the shock wave is induced into the pipe P pipe by elastic reaction force to restore the pipe. It is to prevent excessive flow to the fluid flow or pipeline in (P).

According to the present invention, the pressure chamber C constitutes a two-stage air spring even when the air bag 3 is significantly inflated because the pressure change in the pipe P is severe or the head is excessively large, so that the shock wave is absorbed. And the head in the pipe P is extremely high, so that the shock wave can be absorbed even when the airbag 3 is in contact with the limiting plate 4. Thereby, the water hammer prevention device 1 of the specification which irrespective of the characteristic and the head of the piping P can be used universally.

Although the present invention has been described through specific embodiments in which the first and second features are combined, this is merely for the purpose of illustration and does not limit the invention.

That is, the first and second features of the present invention can be used independently of each other, for example, the implementation of only the first feature of directly connecting the nipple 7 to the airbag 3 in the form of a corrugated box in the configuration of FIG. 2. Alternatively, the diaphragm as shown in FIG. 1 (D: collectively referred to as air bag for convenience) or the closed curved air bag A as shown in FIG. Implementation of only the second feature to be installed is included within the scope of all the invention.

Claims (6)

In the water hammer which forms the pressure chamber which accommodated the compressor body in the body connected to one side of a piping, and isolates the fluid from the compressor body and piping of this pressure chamber with the elastic airbag, The said airbag 3 is the said pipe ( A limiting plate 4 provided on the P side and separating the pressure chamber C into a first space C1 and a second space C2 on the airbag 3 side in the middle of the pressure chamber C. Water hammer preventive, characterized in that is provided. The limiting plate (4) according to claim 1, characterized in that an orifice (5) is formed in the limiting plate (4) to restrict the flow of the compressor body from the first space (C1) to the second space (C2). Water hammer. Water hammer according to claim 1, characterized in that the airbag (3) is configured in the form of a pleat box. Water hammer according to claim 1, characterized in that the airbag (3) is in the form of a closed curved surface. Water hammer according to claim 1, characterized in that the airbag (3) is in the form of a diaphragm. The method according to any one of claims 1 to 5, wherein the axial expansion of the airbag (3) is limited by the limiting plate (4), and the airbag (3) contacts the limiting plate (4). Water hammer preventer, characterized in that the opiris hole (5) is blocked.