JPH0914562A - In-pipe mounting water hammer preventing device and mounting method therefor - Google Patents

Abstract

PURPOSE: To prevent a water hammer phenomenon and to eliminate necessity for mounting space, by receiving a water hammer absorbing member in a bottom part or an intermediate barrel part having an intermediate partitioning wall part, and fixing an object, sealed with an orifice plate, in the upstream of a faucet into a pipe through an elastic film. CONSTITUTION: A water-tight bottom part 12 is provided in one end of an intermediate barrel part 11, to fix an orifice plate 14 to the other end through a water-tight elastic film 13. The water-tight elastic film 13 is formed to be recessed in an orifice plate side, to form a cavity wall 13a effective for absorbing a shock wave between both the film and the orifice plate. In the orifice plate 14, a cylindrical orifice 15a of small diameter X opened to the water-tight elastic film 13 is inserted, and a cylindrical orifice 15b of large diameter Y opened to the opposite direction is inserted. Inside the intermediate barrel part is charged with a foaming bead-shaped water hammer absorbing member 16 to an extent of supporting the water-tight elastic film 13 from the internal surface.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel water hammer preventive device and a method of mounting the same, and more particularly, a water hammer which is observed when a fluid flowing at a constant speed is suddenly stopped by an on-off valve or the like. -A water hammer prevention device for piping inner wear, which can effectively prevent the occurrence of abnormal sound called a phenomenon (water hammer action), and which requires little or no increase in mounting space, and this water hammer prevention. The present invention relates to a method for mounting a container in a pipe.

[0002]

2. Description of the Related Art Conventionally, when a fluid flowing at a constant speed in a water supply facility or a hot water supply facility is suddenly stopped by an on-off valve, a phenomenon known as a water hammer phenomenon (water hammer effect) is known. Has been. When the fluid flowing at a constant speed is momentarily stopped by the on-off valve, the fluid flow instantly becomes zero, and the kinetic energy of the fluid is converted into the fluid pressure rise and the elastic energy of the pipe. Then, the state of zero velocity and the increase of pressure sequentially progresses to the upstream side to form a pressure wave, which reciprocates between the flow passage closing point and the reflection point and is gradually attenuated. This water hammer effect is a water hammer phenomenon. This Wo
The Tahammer phenomenon is frequently occurring due to an increase in fluid pressure based on the improvement of the fluid piping method, the spread of the single lever based on the improvement of the faucet, and the use of synthetic resin for the piping material. Incidentally, the single lever is a faucet capable of instantaneously stopping the flow of liquid, which is a major cause of the water hammer phenomenon. In addition, synthetic resin pipes are more flexible than conventional steel pipes, and it is difficult to completely fix them against vibrations. -It can be said that the degree of noise is increased in addition to the sound generated based on the Tahammer. Furthermore, in the case of water supply using this synthetic resin piping, it is usually 10 to 1
It is said that the cause is that the diameter is as small as 3φ, and therefore the flow velocity is high and the water hammer wave cannot be absorbed completely.

Such a water hammer phenomenon causes an excessive impact, and causes noise and water leakage from piping equipment. Therefore, in order to prevent this water hammer phenomenon, it has been customary to mount a water hammer preventer 80 on the upstream side of the faucet V of the pipe P as shown in FIG. . Here, in the water hammer preventer, the orifice plate 84 is fixed via the watertight elastic film 83 that is supported from the inner surface by the water hammer buffer member 86 (partially omitted) housed inside the container. The orifice plate is provided with a water pipe P and an orifice 85 opening to the watertight elastic film side, and is screwed to a branch pipe Pc of the pipe. As a water hammer buffer member, one using a bellows, a diaphragm, a foam bead, etc. has been developed and put into practical use. The water flow is flowing in the direction of arrow A, but due to the sudden closing of the valve V, a shock wave in the direction of the broken arrow B is generated, the collision is reflected on one of the walls, and the shock wave is reflected in the direction of the broken arrow A. By repeating this, it gradually attenuates. However, all of the conventional water hammer preventive devices are installed in a branch shape outward in the middle of the pipe as shown in the figure, so that a mounting space is required, and it is difficult to install in some places. It has drawbacks. Further, there is a problem that it is a direction perpendicular to the traveling direction of the shock wave and only a part of the shock wave can be absorbed.

[0004]

SUMMARY OF THE INVENTION The present invention overcomes the drawbacks of the conventional water hammer preventer, effectively prevents the water hammer phenomenon, and has a conventional mounting structure. An object of the present invention is to provide a water hammer preventer which can be mounted in a pipe without using a space, and a method of mounting the water hammer preventer in the pipe.

[0005]

As a result of intensive studies to achieve the above object, the inventor of the present invention has accommodated a water hammer buffer member in a hollow body portion having a bottom portion or an intermediate partition wall portion, and has an elastic membrane. It has been found that the object can be achieved by fixing the one sealed with an orifice plate in the pipe through the above, and further by fixing it on the upstream side of the faucet. The present invention has been completed based on such findings.

That is, the gist of the present invention is as follows: (1) A hollow body has a watertight bottom attached to one end and an orifice plate attached to the other end through a watertight elastic film, or the center of the hollow body. The watertight partition wall part,
An orifice plate is attached to both ends via a watertight elastic film, and a gap is formed between the watertight elastic film and the orifice plate.
Inside a pipe consisting of a small-diameter cylindrical orifice that opens to the inner surface side and a large-diameter cylindrical orifice that opens to the outer surface side, and a water hammer buffer member is accommodated in the hollow body part while being supported from the inner surface of the watertight elastic membrane. Water hammer prevention device for mounting. (Second) The water hammer protector for piping interior according to the first aspect, wherein the large-diameter cylindrical orifice has a cone-shaped expanded portion at the open end. (3) The water hammer protection device according to claim 1, wherein the water hammer buffer member is foam beads, balloons, rubber granules, hollow filler-filled silicone gel granules or hollow filler-filled foam synthetic resin granules. . (4) The water hammer protection device for wearing piping interior according to the above 1, wherein the water hammer buffer member is a diaphragm or a bellows. (Fifth) The water hammer protector for wearing piping interior according to any one of the first to fourth aspects, which has a projection for wearing piping interior on the outer peripheral surface of the hollow body portion. (Sixth) A method for mounting a pipe inner water hammer protector, wherein the pipe inner water hammer protector according to any one of the first to fourth aspects is arranged at a location where a part of the fluid pipe is expanded. (Seventh) The mounting method according to the sixth aspect, wherein a concave portion is formed at a location where the diameter is increased, and the pipe interior wearing protrusion according to the fifth aspect is fitted. (Eighth) The orifice plate of the water hammer protector for pipe interior according to the first aspect, wherein the orifice plate is attached to one end of the hollow body and the other end through a water-tight elastic film to prevent fluid The mounting method according to the sixth or seventh aspect, wherein the mounting method is arranged toward the downstream side. (Ninth) Two water hammer protectors attached to the interior of the pipe according to the first aspect, in which a watertight bottom portion is attached to one end of the hollow body portion and an orifice plate is attached to the other end through a watertight elastic film, and the orifices thereof. 8. The mounting method according to the sixth or seventh aspect, wherein the plates are coaxially arranged with the plates facing outward. (Tenth) A watertight partition wall portion is provided at the center of the hollow body portion, and orifice plates are attached to both ends of the hollow body portion through watertight elastic membranes. The mounting method according to the sixth or seventh aspect, wherein.

The contents of the present invention will be described below mainly with reference to the drawings. The water hammer protector for piping interior according to the present invention,
Since it is intended to be installed in a circular pipe under high pressure such as a water pipe, a hollow body having a body portion having a circular cross section is preferably used as the water hammer preventer. The partition wall part at the bottom or the middle part at one end is watertight, and the watertight elastic membrane is used at the other end, and the water hammer buffer member inside is kept watertight. This is because when it is used, its buffer function is likely to be lost due to its absorption, and the above-mentioned buffer function is to be maintained through the watertight elastic membrane. Also, when using a bellows or the like, if it is in direct contact with water, the buffering function against water pressure fluctuation cannot be exhibited. The watertight elastic film is supported from its inner surface by the water hammer cushioning member so that the watertight elastic membrane does not abnormally deform in the hollow body portion and the shock wave is well transmitted to the water hammer cushioning member. When using foam beads or the like as a water hammer cushioning member, the hollow body is filled up to the watertight elastic film. While this water hammer buffer member is fixed in position by the watertight bottom part or partition wall part,
It is configured to absorb a shock wave through a watertight elastic film. Further, the shock wave is effectively absorbed by being received through an orifice arranged outside the watertight elastic film, but an excellent effect can be obtained by configuring the orifice diameter in two stages.

The kind of the water hammer cushioning member in the hollow body is not particularly limited, but synthetic resin foam moldings, synthetic resin foam beads, specifically, polyethylene, polypropylene, polystyrene foam beads, etc., organic or inorganic type. Hollow fillers or synthetic resin foam moldings filled with them,
Specifically, the synthetic resin foam beads, shirasu balloon,
A molded product obtained by filling beads such as glass foam beads into a polyurethane foam or a silicone gel is preferably used, and a mechanical elastic structure such as a bellows is also effective.

FIG. 1 shows an example of a water hammer preventer for wearing piping interior according to the present invention, but the structure of the water hammer preventer 10 is disassembled for each constituent material for easy understanding. The hollow body portion 11 has a watertight bottom portion 12 at one end, and an orifice plate 14 is fixed to the other end through a watertight elastic film 13. The watertight elastic film is provided on the orifice plate side. A hollow wall 1 that is concave and effective for absorbing shock waves
3a is formed between the two. The orifice plate has a cylindrical orifice 15a having a small diameter X (usually X is a diameter of 2 to 5 mm, preferably 3 to 4 mm) opening in the watertight elastic film, and a large diameter Y (opening in the opposite direction) ( Usually Y is 7
A cylindrical orifice 15b having a diameter of -10 mm, but a diameter of 6-9 mm is preferable. A foam bead-shaped water hammer cushioning member 16 is filled in the hollow body portion to such an extent as to support the watertight elastic film from the inner surface (a part thereof is omitted in the drawing).

FIG. 2 shows another example of the water hammer protector for piping interior according to the present invention. The water hammer preventer 20 is disassembled and displayed as in FIG. The hollow body portion 21 has a watertight bottom portion 22 at one end, and an orifice plate 24 is fixed to the other end via a watertight elastic film 23. The watertight elastic film is concave toward the orifice plate side. And an empty wall 23a is formed between them. A small-diameter X cylindrical orifice 25a similar to that shown in FIG. 1 and a large-diameter Y cylindrical orifice 25b opening in the opposite direction are formed through the orifice plate. On the side, a cone-shaped expanded portion is formed, and the opening end has a larger diameter Z (though not particularly limited, it is better to pick up shock waves, so the larger the better). A foam bead-shaped water hammer buffer member 26 is filled in the hollow body portion as in FIG.

FIG. 3 shows still another example of the water hammer preventer for wearing piping interior according to the present invention.
Is disassembled and displayed as in FIG. The hollow body portion 31 has a watertight partition wall portion 32 in the center thereof, and orifice plates 34 are fixed to both ends of the hollow body portion 31 with watertight elastic films 33 interposed therebetween. And a hollow wall 33a is formed between them. The partition wall portion may have elasticity like elastic films at both ends, but in order to individually absorb the shock waves from both ends of the water hammer preventer, it is preferable that the partition wall portion is a rigid body like the bottom portion of FIG. . Each of the two chambers in the hollow body is filled with the foamed bead-shaped water hammer cushioning member 36 as in FIG.

FIG. 4 shows a state in which a water hammer protector 40 for wearing a pipe interior illustrated in FIG. 1 according to the present invention is fixed in a water pipe P. A watertight bottom portion 42 is provided at one end of a hollow body portion 41.
The orifice plate 44 is fixed to the other end through a watertight elastic film 43. The orifice plate has a small diameter orifice 45a and a large diameter orifice 45b. A foam bead-shaped water hammer buffer member 46 is provided in the hollow body portion.
1 is filled as in FIG. 1, and the pipe interior wearing projection 47 on the outer peripheral surface of the hollow body is provided with a recess P provided on the inner surface of the water pipe P.
It is fitted and fixed to a. When the water flow in the water pipe is flowing in the direction of the solid arrow A, the water hammer protector for the interior of the pipe is installed upstream of the faucet V, and the shock wave generated by the sudden closure of the faucet is the dashed arrow. Although it propagates in the direction B and is partially absorbed by the water hammer preventer, the shock wave that is not absorbed proceeds as it is, and if there is an obstacle wall, it is reflected and propagates in the direction of the broken arrow A. Decays while repeating. As described above, the shock wave propagating in the direction of the broken arrow B is the orifice 45b, 45a of the water hammer protector for the interior of the pipe.
It is considered that the foamed bead-shaped water hammer buffer member 46 is absorbed by the foamed bead-shaped water hammer buffer member 46 in which it is gradually compressed and rapidly expanded by the empty wall 43a, and its energy is weakened and collides with the elastic film 43. . If such a water hammer preventer is installed in the water pipe, the water hammer resistance is increased, so that the water hammer preventer preferably has a diameter as small as possible.

FIG. 5 shows a state in which the water hammer protector 50 for wearing a pipe interior illustrated in FIG. 2 according to the present invention is fixed in a water pipe P, and a watertight bottom portion 52 is provided at one end of a hollow body portion 51.
The orifice plate 54 is fixed to the other end through the watertight elastic film 53. The orifice plate has a small diameter orifice 55a and a large diameter orifice 55b.
In addition, the opening of the large-diameter orifice further forms a cone-shaped expanded portion 55c. A foam bead-shaped water hammer buffer member 56 is filled in the hollow body portion as in FIG. 2, and a pipe interior wearing projection 57 on the outer peripheral surface of the hollow body portion is fitted into a recess Pa provided on the inner surface of the water pipe P. It is fixed. When the water flow in the water pipe is flowing in the direction of the solid arrow A, the water hammer protector for the interior of the pipe is installed upstream of the faucet V, and the shock wave generated by the sudden closure of the faucet is the dashed arrow. B
Propagate in the direction, but if there is an obstacle wall, it will be reflected and dashed arrow A
Is propagated in the direction of and then attenuated while repeating this, as in the case described above. A part of the shock wave propagating in the direction of the broken arrow B enters the orifices 45b, 45a of the water hammer protector for piping interior and passes through there, and is gradually compressed. However, since there is a cone-shaped expanded portion at the orifice inlet. It is in a state where it is easy to pick up shock waves. The shock wave collides with the elastic film 53 in a state where the shock wave rapidly expands and weakens its energy, and is absorbed by the foamed bead-shaped water hammer buffer member 56 inside. If such a water hammer preventer is installed in the water pipe, the resistance of the water flow is increased, so that the diameter is preferably as small as possible.

FIG. 6 shows a state in which the water hammer protector 60 for wearing piping interior shown in FIG. 3 according to the present invention is mounted in the water pipe P, and the water hammer preventer is the same as in FIG. A watertight partition wall portion 62 is fixed to the central portion of 61, and an orifice plate 64 is fixed to both ends thereof via watertight elastic films 63. A foam bead-shaped water hammer buffer member 66 is filled in the hollow body portion as in FIG. 1, and a pipe interior wearing projection 67 on the outer peripheral surface of the hollow body portion is fitted into a recess Pa provided on the inner surface of the water pipe P. It is fixed. When the water flow in the water pipe is flowing in the direction of the solid arrow A, the water hammer protector for the interior of the pipe is installed upstream of the faucet V, and the shock wave generated by the sudden closure of the faucet is the dashed arrow. It propagates in the direction B, reflects if there is an obstacle wall, propagates in the direction of the dashed arrow A, and repeats this process thereafter to attenuate. In this case, a part of the shock wave propagating in the direction of the broken arrow B passes through the orifice of the faucet side orifice plate 64, is expanded by the gap 63a, and is absorbed by the water hammer buffer member, but the remaining shock wave. Is propagated in the direction of the broken line arrow A, and the part that is reflected and propagated in the direction of the broken line arrow A passes through the orifice of the orifice plate 64 on the other side (upstream side of the water supply), enters the gap 63a, and It is absorbed by the shock absorbing member. Absorption of shock waves is difficult to be completely absorbed in one round trip, and the energy thereof is rapidly reduced, but usually multiple round trips are inevitable.

FIG. 7 shows the hollow body portion of the water hammer preventer 70 in the mounting method illustrated in FIG. 5 according to the present invention, in which a diameter expansion portion Pb is formed in a part of the water pipe P and a concave portion Pa is provided on the inner surface thereof. 71
The case where the projection 77 provided on the outer peripheral surface of is fixed by being fitted. It is preferable that the inner diameter and the length of the expanded diameter portion are sufficient so that the flow rate per cross-sectional area of the flowing water portion in the water pipe does not change as much as possible. Therefore, it is preferable that the larger the outer diameter of the water hammer preventer, the larger the diameter of the enlarged diameter portion. Even if the diameter of this part is increased, the space required is small compared to the case where the water hammer preventer is attached to the outside like the conventional method, and the piping can be replaced only in this part. It can be used as a member and can be said to be an effective method as compared with the conventional method. In FIG. 7, the water hammer preventer 70 has a watertight bottom 72 at one end of a hollow body 71 and an orifice plate 74 fixed at the other end through a watertight elastic film 73. The plate is provided with a small-diameter orifice 75a, a large-diameter orifice 75b, and a cone-shaped expanded portion 75c. A water hammer impact member 76 is filled in the hollow body portion to such an extent that it can be supported from the inner surface of the watertight elastic film. Protrusion 77 on the outer surface of the hollow body
However, compared to the case of FIG. 5, the length is adapted to the degree of diameter expansion of the water pipe, and thus is longer than the protrusion 57 of FIG. The flow direction of tap water, that is, the solid arrow A, the propagation direction of shock waves, that is, the broken arrows A and B are as described in FIG.

Although not shown in FIG. 4, FIG.
In the above, by installing the same two water hammer preventers as shown in the drawing, by arranging the bottom side of each of them in a facing manner (that is, arranging so that each orifice plate faces the opposite side),
It is convenient because the same effect as in the mounted state shown in FIG. 6 can be obtained, and various kinds of modes can be used with one type of water hammer preventer. It is sufficient that the water hammer protector is installed at the upstream side of the faucet in the water pipe, but usually 3 to 10 m.
It is installed within a range of about 6 to 8 m. Further, in the case of installing the water hammer preventer according to the present invention, when a bent portion of the water pipe is required on the upstream side of the faucet, the shock wave is easily reflected by the bent portion, and also leads to damage of the portion. In some cases, it is preferable to install the water hammer preventer between the bent portion and the faucet. It has already been described that FIG. 8 shows the installation state of the water hammer preventer according to the conventional method.

[0017]

EXAMPLE The water hammer preventer 90 shown in FIG. 2 was attached to the expanded diameter portion Pb of the water pipe P in the same manner as the attaching method shown in FIG. The outer diameter of the hollow body of the water hammer protector is 30 mm, the inner diameter is 28 mm, the small diameter orifice is 3 mm diameter, the large diameter orifice is 9 mm diameter, the opening portion of the expanded diameter portion is 13 mm diameter, and the water hammer cushioning material is about 2 mm. Diameter expanded polystyrene beads were used. A one-lever water faucet R is attached to a water pipe with an inner diameter of 13 mm, and a diameter-expanded portion with an inner diameter of 33 mm is formed at a position 7 m upstream of the water tap R, and a water hammer prevention device is installed in the inside with the orifice side facing the faucet side. did. The water hammer prevention function is to bring a part of the water pipe equipped with the water hammer preventer Pd between the one lever type faucet of the tester shown in FIG. 9 and the pressure measuring instrument S close to the pressure measuring instrument. After connecting, various water pressures were set by the water pressure variable device T, and the relationship between the maximum water pressure and the impact noise in the case of quick closing of the faucet was investigated. In parallel, we also investigated the case without using a water hammer protector for piping. These results are shown in FIG. 10 (X axis: supply water pressure, Y axis: maximum water pressure during water hammer), but when the water hammer preventer was used, the pressure change was small and the maximum water pressure was not so high. In addition, no impact noise was generated, but when the water hammer was not used, the pressure change was large and the maximum water pressure was very high, and the impact noise was generated when the supply water pressure was 2 kgf / cm ^2. Started to do.

[0018]

As described above, the water hammer protector worn on the interior of the pipe and the mounting method thereof according to the present invention have been described. By using the water hammer preventer and adopting the mounting method, the water hammer can be exposed to the outside of the pipe. A large space for installing the preventive device is not required, and the water hammer sound generated by the sudden closing of the faucet can be minimized as in the conventional case.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an example of a water hammer protection device for wearing a pipe interior according to the present invention in an exploded state thereof.

FIG. 2 is a cross-sectional view showing another example of the water hammer protector for wearing piping interior according to the present invention in an exploded state thereof.

FIG. 3 is a cross-sectional view showing still another example of the water hammer protector for wearing piping interior according to the present invention in its exploded state.

FIG. 4 is a cross-sectional view of an example of a state in which the water hammer protector for piping interior shown in FIG. 1 according to the present invention is mounted in a water pipe.

FIG. 5 is a cross-sectional view of an example of a state in which the water hammer protector for piping interior shown in FIG. 2 according to the present invention is mounted in a water pipe.

FIG. 6 is a cross-sectional view of an example of a state in which the water hammer protector for piping interior shown in FIG. 3 according to the present invention is mounted in a water pipe.

FIG. 7 is a cross-sectional view of an example of a state in which the water hammer preventer shown in FIG. 2 is mounted in a water pipe having an enlarged diameter portion.

FIG. 8 is a cross-sectional view showing a mounted state of a conventional water hammer preventer.

FIG. 9 is a main part of a water hammer prevention function measuring device.

FIG. 10 is a graph showing measurement results of water hammer prevention function measurement.

[Explanation of symbols]

10, 20, 30, 40, 50, 60, 70, 90: Piping interior worn water hammer prevention device 80: Piping exterior worn water hammer prevention device 11, 21, 31, 41, 51, 61, 71: Hollow body 12 , 22, 42, 52, 72: Watertight bottom 13, 23, 33, 43, 53, 63, 73, 83: Watertight elastic film 13a, 23a, 33a, 43a, 53a, 63a: Void 14, 24, 34 , 44, 54, 64, 74, 84: Orifice plate 15a, 25a, 35a, 45a, 55a, 75a: Small diameter orifice 15b, 25b, 35b, 45b, 55b, 75b: Large diameter orifice 85: Orifice 25c, 55c, 75c : Cone-shaped expanded portion 16, 26, 36, 46, 56, 66, 76, 86: foam beads 37, 47, 57, 67, 77: protrusion P: water pipe Pa: recess Pb: Expanded portion of water pipe Pc: Branch pipe Pd: Part of water pipe R: One-lever water faucet S: Pressure measuring device T: Water pressure variable device V: Water faucet A (solid arrow): Flow direction B (dashed arrow) ): First shock wave propagation direction A (dashed line arrow): Reflected wave propagation direction

Claims (10)

[Claims] 1. A hollow body has a watertight bottom attached to one end and an orifice plate attached to the other end via a watertight elastic film, or a watertight partition wall at the center of the hollow body, Orifice plates are attached to both ends with a watertight elastic film, and a gap is formed between the watertight elastic film and the orifice plate.The orifice of the orifice plate has a small diameter that opens to the inner surface side. A pipe characterized by comprising a cylindrical orifice and a large-diameter cylindrical orifice that opens to the outer surface side, and a water hammer buffer member is accommodated in the hollow body while being supported from the inner surface of the watertight elastic membrane. Water hammer prevention device for mounting. 2. A water hammer protection device for wearing piping interior according to claim 1, wherein the opening end of the large-diameter cylindrical orifice has a cone-shaped expanded portion. 3. A water hammer buffer member comprising foam beads, a balloon,
The water hammer protector worn on the interior of a pipe according to claim 1, which is a rubber granule, a hollow filler-filled silicone gel granule or a hollow filler-filled expanded synthetic resin granule. 4. The water hammer protector worn on the interior of a pipe according to claim 1, wherein the water hammer buffer member is a diaphragm or a bellows. 5. The water hammer protection device for wearing a pipe interior according to claim 1, wherein a projection for wearing a pipe interior is provided on the outer peripheral surface of the hollow body portion. 6. A pipe inner wearing water hammer preventer equipped with a pipe inner wearing water hammer preventer according to claim 1, wherein the pipe inner water hammer protector is arranged at a location where a part of the fluid pipe is expanded in diameter. Method. 7. The mounting method according to claim 6, wherein a recess is formed in a location where the diameter is increased, and the pipe interior wearing projection according to claim 5 is fitted. 8. The orifice plate of the water hammer protector according to claim 1, wherein a watertight bottom part is attached to one end of the hollow body, and an orifice plate is attached to the other end of the hollow body via a watertight elastic film. The mounting method according to claim 6 or 7, wherein the mounting method is arranged toward the downstream side of the. 9. A pipe inner water hammer protector according to claim 1, wherein an orifice plate is attached to one end of the hollow body and a watertight elastic film is attached to the other end. The mounting method according to claim 6 or 7, wherein the orifice plates are coaxially arranged so as to face opposite to each other. 10. A water hammer protector for pipe interiors according to claim 1, wherein a watertight partition wall is provided at the center of the hollow body, and orifice plates are attached at both ends with watertight elastic membranes. The mounting method according to claim 6 or 7, which is provided.