JPH0641799B2 - Water hammer prevention device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field and Outline of the Invention] The present invention is directed to a water hammer effect generated in a pipe due to an eccentric deformation of a pressure receiving membrane (pressure absorbing portion) that partitions a hollow body. The present invention relates to a water hammer prevention device that absorbs a sudden pressure change due to the internal volume of the main body by increasing the surface area of the pressure absorption section with respect to the internal volume of the main body and reducing the deformation resistance of the pressure absorption section at the time of pressure absorption. Even if the size is small, the water hammer phenomenon can be sufficiently prevented.

More specifically, the pressure-receiving membrane is formed into a bag-shaped body so that the bag-shaped body is elongated and flattened when the pressure rises due to the water hammer action.

[Prior art and its problems] When the water faucet (V) provided at the end of the piping path of the water circuit is suddenly closed, the pressure on the upstream side near the water column (V) rises abnormally. It becomes a wave and propagates along the piping route. This is a so-called water hammer phenomenon, and the propagation of this pressure wave may be transient depending on the condition of the pipe, but in principle, it repeatedly reciprocates. When this water hammer phenomenon occurs, there is a risk that abnormal noise will be generated in the pipe portion where the pressure wave collides, and in some cases, the pipe will be broken.

In order to solve the above problem, conventionally, a water hammer prevention device as shown in FIG. 10 is inserted in a pipe path upstream of the faucet (V) as shown in FIG.

This water hammer prevention device, as shown in the figure, has a hollow spherical main body (1) inside the air chamber (A) and the water chamber at the central part by a pressure receiving membrane (4).
It is divided into (B), and an inert gas body is injected into the air chamber (A) from a gas inlet, and the air chamber (A) is in a constant pressurized state. As shown in the figure, the pressure-receiving film (4) has a shape that protrudes in a substantially hemispherical shape along the inner surface of the water chamber (B) as a whole, and has a recess (46) in the center thereof to form a cross section W. It is formed in a letter shape.

The other water chamber (B) is provided with a connection port (12), and the recess (46)
It is located opposite to. In addition, an inert gas is filled into the air chamber (A) from the gas inlet at a constant pressure, and this pressure keeps the pressure receiving membrane (4) as a whole protruding toward the connection port (12) side. Has been done.

As shown in FIG. 3, the water hammer prevention device having the above structure is used with its connection port (12) connected to the pipe path,
In this state, the water chamber (B) is pressurized by the water pressure in the piping path, but the pressure receiving membrane (4) as a whole protrudes toward the connection port (12) side due to the pressure in the air chamber (A). Has been maintained.

When the water faucet (V) of this piping path is suddenly closed, a water hammer phenomenon occurs and a high pressure pressure wave is generated from the water faucet (V) toward the upstream side, but the pressure wave is the connection port (12). Is transmitted to the air chamber (A), and the pressure in the air chamber (A) rises sharply. At this time, the concave portion (46) is pushed up as the pressure rises, and the pressure receiving membrane (4) is deformed into the shape shown by the chain double-dashed line in FIG. Due to this deformation, the volume of the water chamber (B) is increased, and the rise in pressure of the water chamber (B) is absorbed thereby.
That is, the surface of the pressure receiving film (4) functions as a pressure absorbing portion. Therefore, the subsequent transmission of the pressure wave is prevented.

However, the above structure has a problem that the water hammer phenomenon cannot be sufficiently prevented when the main body (1) is small.

This is because when the above-mentioned conventional one is miniaturized as it is, the surface area of the pressure receiving membrane (4) as a pressure absorbing portion becomes smaller accordingly, and as a result, the water chamber (B) due to the deformation of the pressure receiving membrane (4). This is because the volume change amount (pressure absorption amount) cannot be set to a sufficient value.

That is, in the above conventional one, the pressure receiving membrane (4) is arranged in the lower half of the hollow spherical body, and the pressure receiving membrane (4) is provided.
The volume of the part surrounded by is about half of the air chamber (A). Since the volume of this part is changed (deformation of the pressure receiving membrane (4) to the air chamber (A) side) to absorb the pressure during pressure wave propagation, the entire hollow spherical body can be made compact. In the case of conversion, the volume change region becomes smaller by that amount and the pressure cannot be sufficiently absorbed. Also, if an attempt is made to secure a sufficient volume change amount under this condition, the displacement amount of the central portion of the pressure receiving membrane (4) becomes abnormally large, and the pressure receiving membrane (4)
This is because the deformation pit of (1) becomes large.

[Technical Problem] The present invention divides such a “hollow body (1) into an air chamber (A) and a water chamber (B) by a flexible pressure receiving membrane (4),
In a water hammer prevention device in which the air chamber (A) is in a pressurized state and the connection opening (12) provided in the water chamber is connected to a water circuit for communication, even if the main body (1) is small In order to prevent the impact phenomenon sufficiently, the pressure receiving area of the air chamber (A) is increased by increasing the volume ratio of the part surrounded by the pressure receiving membrane to the inner volume of the air chamber (A). And pressure receiving membrane
An object of the present invention is to increase the amount of volume change of the water chamber (B) due to the smooth deformation of (4) and to improve the performance so that the deformation can be performed smoothly.

[Technical Means] The technical means of the present invention taken to solve the above-mentioned problem is that "the main body (1) is a body-length closed cylindrical body provided with a connection port (12), (4) is formed into a bag-like body (F) which is one size smaller than the main body (1) and surrounds the whole or most of the air chamber (A) to form a bag-like body (F), and the bag-like body (F) Enclosed by the water chamber (B), a plurality of reinforcing portions that are substantially parallel to the axial direction of the bag-shaped body in the body-portion forming film of the bag-shaped body (F) are provided over almost the entire area of the body, The reinforcing portion is configured to be less likely to bend than other constituent films. ”

[Operation] The above technical means operates as follows.

The bag-like body (F) is formed into a closed cylindrical body with a long body as a whole,
Furthermore, since it is formed in a size slightly smaller than the main body (1), the volume ratio of the portion surrounded by the bag-like body (F) in the air chamber (A) is the same as that of the conventional example described above. It will be larger than The entire bag-like body (F) is surrounded by the water chamber (B) communicating with the water circuit.

Therefore, of the constituent walls of the air chamber (A) formed in the main body (1), the whole or most of the walls are pressure receiving parts from the water chamber (B), and the air chamber (A The pressure receiving area of the constituent wall is large.

When a water hammer phenomenon occurs in the water circuit equipped with this water hammer prevention device, the pressure wave is transmitted from the connection opening (12) to the surrounding portion of the bag-like body (F), and the water chamber (B) The pressure rises sharply.

Along with this, the constituent wall of the air chamber (A) is pressurized over the entire area. Since all or most of the constituent walls of the air chamber (A) are a bag-like body (F) composed of a flexible pressure receiving membrane, all or most of the constituent walls of the air chamber (A) are The pressure receiving film, which serves as a pressure absorbing portion and constitutes the bag-like body (F), is deformed so as to bend toward the air chamber (A).

Further, due to the shape of the bag-like body (F), the area of the body is extremely larger than the areas of both ends. Therefore, the total sum of the pressures acting on the body of the bag-like body (F) is larger than the total sum of the axial pressures acting on the end of the bag-like body (F).

On the other hand, the bag-like body (F) is formed in the shape of a body length, and moreover, since a plurality of reinforcing portions parallel to the axial direction are formed, compared with the deformation resistance in the direction of compressing in the axial direction, The deformation resistance is small in the direction of flattening at right angles to the axis. As a result, when the pressure in the water chamber (B) rapidly rises, the bag-like body (F) is deformed in a flattened manner. That is, the volume of the air chamber (A) is likely to change as compared with the conventional one described above.

In particular, since the reinforcing portion is less likely to bend than the other constituent membranes, the constituent membranes between the reinforcing portions are deformed in the direction perpendicular to the axis, and the bag-shaped body at the time of water hammer pressure absorbing operation. The compression deformation direction and the compression deformation portion of (F) become constant.

[Effects] The present invention having the above-described configuration has the following unique effects.

When the pressure wave propagates to the water chamber (B), the amount of deformation of the entire constituent wall of the bag-like body (F) accompanying the increase in pressure becomes large,
Since the pressure absorption amount (volume change of the air chamber (A)) is large, even if the main body (1) is small, it is possible to sufficiently prevent the water hammer phenomenon in the part surrounded by the bag-like body (F). Becomes In other words, the main body (1) can be downsized.

Since the compression deformation direction and the compression deformation part of the bag-like body (F) during the water hammer pressure absorption operation are constant, the compression deformation operation of the bag-like body (F) is smooth and the water hammer pressure absorption operation is more reliable. Becomes

[Embodiment] An embodiment of the present invention will be described below with reference to FIGS. 1 to 10.

As shown in FIG. 1, the water hammer prevention device of the first embodiment shown in FIGS. 1 and 2 has a dish-shaped lid (2) at one end open portion of a tubular body (10) whose both ends are open. Attached to form a hollow main body (1), the pressure receiving membrane (4) is formed into a deep bottomed cylindrical shape to form a bag-like body (F), which is the cylindrical body (10) of the main body (1). ), This bag (F)
The flange portion is clamped and fixed between the cylindrical body (10) and the lid (2), and the inside of the main body (1) is partitioned by this bag-shaped body (F).
Then, the void enclosed by the bag-like body (F) and the lid (2) becomes the air chamber (A), and the void enclosed by the bag-like body (F) and the tubular body (10) is water. It becomes a room (B).

As shown in the figure, the tubular body (10) is provided with a flange (11) having an annular fitting groove (14) at the upper open end, and the other lower end is reduced in diameter to be connected. The water hammer prevention device is attached to a pipe as a water circuit by forming a mouth (12) and screwing the connection mouth (12) into a connecting pipe such as a socket provided in the pipe.

As shown in the same figure, the lid (2) is provided with a flange (21) similar to the above-mentioned flange (11) in its open portion, and a gas communicating with the air chamber (A) is provided in the center of the top wall. An injection valve (22) is provided.

As shown in FIG. 1 and FIG. 2, the bag-like body (F) has a body having a tapered shape and a distal end formed in an arcuate cross-section. It is slightly smaller than the inner diameter of the tubular body (10), and the length from the flange (40) to the bottom wall is from the upper end of the connection opening (12) of the tubular body (10) to the flange (11). Up to the length. Then, a flange (40) having substantially the same shape as the flange of the lid (2) and the like is arranged at the open end, and the flange (40) has a ridge (40) corresponding to the fitting groove (14). 42) is provided. The convex groove (42) is formed on the flange of the tubular body (10), and the fitting groove (1
The bag-like body (F) is fixed in the tubular body (10) so as to be concentric with the tubular body (1) by being fitted into the tubular body (1).
The gap between 0) and the bag-like body (F) is uniform over the entire circumference.

Further, on the outer peripheral surface of the bag-shaped body (F), as shown in the figure,
Plural ridges (41) continuous from the upper end of the body to the tip,
(41) is provided, and as shown in FIG. 2, the ridges (41), (41) are arranged so as to have a cross shape at the tip of the bag-like body (F). That is, the ridges (41), (41) are the reinforcing portions described in the second claim.

This water hammer prevention device is used in the same manner as the above-mentioned conventional example, but in this use state, the gas injection valve (22) is connected to the air chamber (A).
Inert gas is injected into the inside according to the flowing water pressure in the pipe. In this state, due to the injection pressure, the bag-like body (F)
As shown in FIG. 1, the bottom wall portion thereof is maintained as a whole as a tubular body protruding toward the connection port (12) side.

In this case, the pressure wave is generated by the water hammer action (1
When the water is transferred from 2) into the water chamber (B), the internal pressure in the water chamber (B) rapidly rises and the pressure wave collides with the bottom wall of the bag (F), (F) Ascends and propagates in the gap with the tubular body that surrounds the body. Since the cross section of this propagation path is gradually reduced, the pressure wave will be attenuated to some extent during this propagation process.

Also, overall, when the pressure in the water chamber (B) rises,
The bag-like body (F) is deformed so as to be flattened by the above-mentioned action, but the ridges (41), (4
Since 1) is arranged parallel to the axis at the same interval, the bag-like body (F) is prevented from bending in the axial direction due to the rigidity of the ridges (41) and (41) to some extent. It will be deformed in the state where it was kept. That is, the ridge of the cross section of the bag-like body (F)
The bag-like body (F) is deformed so that the thin-walled portions between (41) and (41) are bent inward so as to form a substantially cross shape.

As described above, in this example, the direction of deformation of the bag-like body (F) is determined, and the bag-like body (F) is smoothly deformed when the internal pressure of the water chamber (B) rises. The shot-preventing action is stable.

Here, the water hammer prevention effect of the water hammer prevention device of the above-described embodiment under the conditions of flowing water pressure: 1 kgf / cm ² , flowing water: 201 / min, pipe length 10 m, and pipe diameter 15 mm is described. The experimental results are shown in comparison with those of the constitution and further in comparison with the case of not using the water hammer prevention device (Figs. 4 to 6).

The graph shown in FIG. 4 is a graph showing the pressure change in the pipe when a water hammer phenomenon is generated in the above pipe, and the first pressure wave of the pipe reaches 19.8 kgf / cm ² and is attenuated. However, the water hammer phenomenon continues for 0.36 seconds.

The graph shown in FIG. 5 shows a pressure wave propagating in the pipe when the water hammer prevention device of the description conventional example is inserted into the pipe, and the first pressure wave of this is 8.7 kgf / cm. ^It has reached ² , and the water hammer phenomenon continues for 0.36 seconds while decaying.

The graph shown in FIG. 6 shows a pressure wave propagating in the pipe when the water hammer prevention device of the embodiment of the present invention is inserted into the pipe, the first wave of which is 3.1 kgf / cm ² And even the largest pressure wave after that was 5.8 kgf / cm ² .

From the above, the water hammer prevention effect of this embodiment,
It is clear that it is far superior to the above-mentioned conventional example.

For reference, the spherical body of the conventional device has a diameter of 85 mm and a height of 100 mm, and the body (1) of the first embodiment has a diameter of 32 m.
It was a cylinder with m and a height of 85 mm.

From this, in the above-mentioned embodiment, the water hammer prevention effect is remarkable even if it is smaller than the conventional water hammer prevention device.

In the above embodiment, the cross portions of the protrusions (41) and (41) in the bottom wall portion of the bag-like body (F) are combined, but as shown in FIG. If the notch (49) is provided in the part and each ridge (41) is divided into two, the deformation resistance near the bottom of the bag-like body (F) becomes small, and the bag-like body (F) is more easily deformed. Will be things. Further, as shown in FIG.
1), (41) The bag-shaped body can be formed by making the mutual area flat in advance or by projecting it inward.
(F) becomes even more easily deformable.

Further, in the above-mentioned embodiment, the ridges (41), (41) parallel to the axial direction are provided on the body part in order to give the bag-like body (F) a tendency to deform, but the ridges (41) , (41) may be formed in a gentle spiral shape on the body of the bag-like body (F).

Further, the ridges (41) and (41) are arranged in order to allow the bag-shaped body (F) to be deformed in a state where the axial flexure is blocked. It is also possible to make the thickness of the constituent film of (4) constant and insert a reinforcing member such as a thin leaf spring into the inside thereof. Further, the air chamber (A) may be filled with pressurized air in addition to being filled with an inert gas body, and in some cases, the air chamber (A) is set to the atmospheric pressure state. The pressure may be applied when connected to the water circuit.

Next, in the second embodiment shown in FIG. 9, the bag-like body (F) is made into a rugby ball-like hollow body, and the mouth portion (23) is opened at one end on the major axis side thereof, and the gas injection valve ( 22) penetrates the top wall of the main body (1) so as to communicate with the mouth portion (23) .In this case, the entire empty space surrounded by the bag-like body (F) is It becomes the air chamber (A), and the pressure receiving area is further increased when the volume of the air chamber (A) is constant as compared with that of the first embodiment, and the water hammer prevention effect is further improved from the above-mentioned action. It will be done.

In addition, the gas inside the bag-like body (F) does not leak,
In the case of a water hammer prevention device of the type that only needs to set the internal pressure of (F) to a constant value, a bag-like body (F) that is completely separated from the body (1) and is completely enclosed is enclosed in the body (1). Only by doing so, the same effect as the above embodiment can be obtained.

In the above embodiment, the ridges (41) are formed on the constituent film of the bag-like body (F),
(41) and a plurality of reinforcing members (H) on the constituent film
In the case where a plurality of reinforcing portions are formed in the longitudinal direction on the constituent film of the bag-like body (F) and the reinforcing portions are provided over substantially the entire region of the body, such as the one in which the Since the deformation direction of the bag-shaped body (F) during the initial deformation is determined to be a direction that is elongated and flattened, the flattening of the bag-shaped body (F) proceeds smoothly, and a further water hammer prevention effect Will improve.

[Effects] The present invention having the above-described configuration has the following unique effects.

When the pressure wave propagates to the water chamber (B), the amount of deformation of the entire wall of the bag-like body (F) accompanying the increase in pressure becomes large,
Since the pressure absorption amount (volume change of the air chamber (A)) is large, even if the main body (1) is small, it is possible to sufficiently prevent the water hammer phenomenon in the part surrounded by the bag-like body (F). Becomes In other words, the main body (1) can be downsized.

The compressive deformation direction and compression deformation part of the bag-like body (F) during the water hammer pressure absorbing operation are constant, so the compressive deformation operation of the bag-like body (F) is smooth and the water hammer pressure absorbing operation is more reliable. Becomes

[Brief description of drawings]

FIG. 1 is an explanatory view of a water hammer prevention device according to an embodiment of the present invention, and FIG.
FIG. 4 is a cross-sectional view of the bag-like body (F) of the embodiment of the present invention, FIG. 3 is a view showing a mounting position of the water hammer prevention device, and FIGS. 4 to 6 are pressure fluctuation diagrams in the pipe. FIG. 7 shows a bag-like body (F) of another embodiment.
FIG. 8, FIG. 8 and FIG. 9 are explanatory views of a water hammer prevention device of another embodiment, and FIG. 10 is an explanatory view of a water hammer prevention device of a conventional example, in which (A) ... Air chamber (B) …… Water chamber (F) …… Bag (1) …… Main body (4) …… Pressure receiving membrane (12) …… Connection port (S) …… Support rod

Claims (1)

[Claims] 1. A flexible pressure receiving membrane is provided inside a hollow main body (1).
(4) is divided into an air chamber (A) and a water chamber (B), the air chamber (A)
In a water hammer prevention device in which the connection port part (12) provided in the water chamber under pressure is connected to the water circuit for communication, the main body (1) is provided with the connection port part (12). The body is a closed cylindrical body, and the pressure-receiving membrane (4) is smaller than the main body (1) and is formed into a body-shaped bag-like shape that surrounds the whole or most of the air chamber (A). F), the bag-like body (F) is surrounded by the water chamber (B), and a plurality of reinforcing portions that are substantially parallel to the axial direction of the bag-like body are formed on the body forming film of the bag-like body (F). A water hammer prevention device having a structure in which the reinforcing portion is arranged to be less likely to bend than other constituent films, and is arranged over substantially the entire area of the body portion.