JP3375437B2 - Water hammer absorber - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water hammer absorber which is disposed in a pipe such as a water supply pipe or a hot water supply pipe to damp a water hammer generated in the pipe.

[0002]

2. Description of the Related Art As shown in FIGS. 4 (a) and 4 (b), a water supply pipe 10 for supplying water to a single lever faucet (faucet) 12 and a hot and cold water mixing tap 13 of a fully automatic washing machine or the like , Hot water supply pipe to supply water
In the water supply pipe 11 and the water supply pipe 10, the pressure in the pipes such as the water supply pipe 11 and the water supply pipe 10 may suddenly rise due to the rapid closing of the water faucet 12 and the hot water / water mixing tap 13, and a water hammer may occur. Such a water hammer not only causes impulsive noise, but also causes damage to faucet equipment, piping, and the like. So, to dampen and buffer the water hammer,
The water hammer absorber 1 is arranged in the water supply pipe 10 and the hot water supply pipe 11 in the vicinity of the water faucet 12 and the hot and cold water mixing tap 13.

FIG. 5 shows a conventional example of the water hammer absorber 1 (see, for example, Japanese Patent Laid-Open No. 3-272378), in which a pipe portion 15 is connected to a water supply pipe 10, and a venturi pipe 16 is provided inside the pipe portion 15.
Is provided, and the communication hole 19 of the venturi tube 16 is communicated with the inside of the venturi tube 16 by the through hole 18 of the throttle portion 17 of the venturi tube 16. A cylinder 20 is formed integrally with the tubular portion 15, and a cylinder lid 23 is screwed into the opening end of the cylinder 20 to form a cylinder.
A piston 24 is slidably fitted into the inside of 20. Piston 24
A plurality of springs are provided in the cylinder chamber between the cylinder lid 23 and the cylinder lid 23, and the pressure receiving surface outside the piston 24 and the communication chamber 19 are communicated with each other via the communication port 21.

In the water hammer absorber 1 shown in FIG. 5, when the water faucet is closed, the piston 24 is pushed back by the water supply pressure (dynamic water pressure) acting on its pressure receiving surface. It stops at a position where it balances with the power. At this time, when the faucet is opened and a water flow is generated in the water supply pipe 10, the pressure in the cylinder 20 communicating with the throttle portion 17 of the Venturi pipe 16 is reduced, and the piston 24 moves the left end portion (left end in FIG. 5) of the cylinder 20. )
Is pushed out to. Then, when the faucet is suddenly closed, a sudden pressure increase occurs and propagates in the water supply pipe 10, and the water in the water supply pipe 10 escapes into the cylinder 20, whereby the pressure increase is absorbed and the water hammer phenomenon occurs. Is avoided.

In the above-mentioned conventional example, when high-pressure water is supplied to the water supply pipe 10 and the force due to water pressure (dynamic water pressure) exceeds the set pressure of the spring, the initial value of the piston 24 changes and the initial cylinder volume (cylinder chamber Volume) becomes smaller.
As the initial cylinder volume becomes smaller, the cylinder volume change rate becomes smaller, and the water hammer absorption performance of the water hammer absorber decreases. Even if the pressure supplied to the water supply pipe 10 becomes high, if the spring load is increased, the water hammer absorption performance does not decrease.However, if the spring load is increased, the water hammer absorption cannot be performed when the water pressure is low. There is.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to make a water hammer absorber capable of exerting a water hammer absorbing performance without replacing the spring even when the pressure of the supplied fluid becomes large. And

[0007]

The present invention provides a cylinder (2, 3
The piston (3) is slidably and watertightly fitted in the inside of (8), and the coil spring (5) is arranged so as to bias the piston (3) toward one end of the cylinder (2, 38). ,Cylinder
Piston with coil spring (5) in (2,38)
In the water hammer absorber in which the inside of (3) is made into the cylinder chamber (7) and the pressure receiving surface (32) on the outside of the piston (3) communicates with the pipe through the through hole (6), (7) Enclose gas and solid (33) to fill dead space,
Alternatively, the solid (33) and liquid (including semi-solid) for filling the gas and dead space are enclosed in the cylinder chamber (7). The present invention, in the above configuration,
As a solid (33) to fill the dead space, a cylindrical solid can be inserted into the inner diameter of the coil spring (5), and the outer diameter of the cylindrical solid to fill the dead space of the coil spring (5). Can be smaller than the inner diameter (cylinder solid can be inserted in the coil spring,
It shall not affect the function of the coil spring. ),
The cylinder (26,41) of the cup-shaped plug (4,39) is screwed into the other end of the cylinder (2,38), and the cylinder (2,38) and plug (4,39)
It is possible to seal the gap between the cylindrical portion (26, 41) of the coil by the O-ring (30, 51) and to support the other end of the spring (5) by the plug (4, 39).
The outer diameter of (5) can be made smaller than the inner diameter of the cylindrical part (27) of the piston (3) and the inner diameter of the cylindrical part (26,41) of the plug (4,39) (which affects the function of the coil spring. , A cylindrical solid to fill the dead space inside the cylinder (2,38) or the cup-shaped plug (4,39)
A solid cylinder that can be fixed inside the cylinder to fill the dead space can be integrated with the cylinder (2,38) or the cup-shaped plug (4,39) to fill the dead space. The length of the column-shaped solid depends on the length of the piston (3) when the tip of the cylinder (27) of the piston (3) and the tip of the cylinder (26,41) of the plugs (4,39) abut. The length may be equal to or shorter than the distance between the side surface and the inner surface of the plug (4, 39), and a lubricant may be enclosed as a liquid for filling the dead space. According to the present invention, in the above structure, the second through hole (47) is further provided on one end side of the housing (35), and the first through hole is provided on the other end side of the housing (35).
(46) are respectively formed, the cylinder (38) is arranged in the housing (35) with a predetermined gap, and the pressure receiving surface (32) of the piston (3) faces the second through hole side (47). The first through hole (46) and the second through hole (47) can be made to communicate with each other through the gap (45), and the male screw of the small diameter portion (43) on one end side of the cylinder (38) can be formed. The female screw of the small diameter portion (44) of the second connecting fitting (49) is screwed, and the male screw of the cylindrical portion of the second connecting fitting (49) is attached to the housing (3
5) is screwed into the female screw at one end, and the communication hole (42) is formed in the small diameter portion (43) at one end of the cylinder (38), and the first communication hole (46)
Can be communicated with the second through hole (47) through the gap (45) and the through hole (42).

[0008]

[Operation] The pressure receiving surface (32) on the outer side of the piston (3) is communicated with the pipe through the through hole (6), and is communicated with the water supply source and the faucet through the pipe. When the water faucet is closed, the piston (3) is pushed back by the water supply pressure (dynamic water pressure) acting on its pressure receiving surface (32), and the force due to the water supply pressure and the urging force of the spring (5) and the cylinder chamber ( 7) Stop at a position where the force due to the internal pressure balances. Next, when the faucet is opened and a water flow is generated in the water supply pipe, the pressure on the pressure receiving surface (32) of the piston (3) communicating with the through hole (6) decreases, and the piston (3) moves to the spring (5). It is moved by urging force, etc. and stops at the new balance position. When the faucet is closed suddenly, a sudden pressure rise occurs in the pipe, and the sudden pressure rise propagates to the pressure receiving surface (32) of the piston (3),
The piston (3) rapidly moves to the cylinder chamber (7) side, and the water in the pipe escapes into the cylinder (2, 38), whereby the rise in pressure is absorbed and the occurrence of the water hammer phenomenon is avoided. In the present invention, since a solid or "solid and liquid" for filling gas and dead space is inserted in the cylinder chamber (7),
A large rate of change in the cylinder volume in the cylinder chamber (7) can be achieved.

[0009]

1 to 2 show a first embodiment of a water hammer absorber 1 according to the present invention.
An example is shown. One end of the cylinder 2 of the water hammer absorber 1 (Fig. 1
The through hole 6 is formed in the small diameter portion at the left end), and the male screw of the cylindrical portion 26 of the cup-shaped plug 4 is screwed into the female screw at the other end (right end in FIG. 1) of the cylinder 2. A piston 3 is slidably fitted in the cylinder 2, a coil spring 5 is provided in a cylinder chamber 7 between the piston 3 and the plug 4,
The urging force of the coil spring 5 urges the piston 3 toward one end. The cylindrical portion 27 of the piston 3 and the cylindrical portion 26 of the plug 4 are located opposite to each other, and an O-ring 30 is attached to the annular groove on the outer peripheral surface of the cylindrical portion 26 of the plug 4 and
The plug 4 and the cylinder 2 are hermetically sealed. There are three annular grooves on the outer peripheral surface of the cylindrical portion 27 of the piston 3,
An O-ring 28 is mounted in each of the annular grooves, and the O-ring 28 seals the piston 3 and the cylinder 2 in a watertight manner. An annular contact surface 31 is formed at one end of the inner surface of the cylinder 2 and serves as a stopper for the piston 3.

FIG. 1A shows a state in which the piston 3 is located at the initial end of the stroke L and the piston 3 is in contact with the annular contact surface 31. At this time, the cylinder volume of the cylinder chamber 7 (piston 3 V ₁ is the volume of the cylinder chamber surrounded by the inner surface of the cylinder 7, the inner surface of the cylinder 7 and the inner surface of the plug 4. Figure 1 (c)
The piston 3 is located at the end of the stroke L, and the tip of the cylindrical portion 27 of the piston 3 (the right end in FIG. 1) and the tip of the cylindrical portion 26 of the plug 4 (the left end in FIG. 1) are in contact with each other. The cylinder volume of the cylinder chamber 7 at this time is V ₂ . Figure 1
(b) shows a state where the piston 3 is positioned in the middle of the stroke L, and the cylinder volume of the cylinder chamber 7 at this time is V ₁ ′. The through hole 6 of the water hammer absorber 1 is connected to a water supply pipe or the like, and the water pressure p [kPa] acts on the pressure receiving surface 32 of the piston 3. Assuming that the pressure receiving area of the pressure receiving surface 32 of the piston 3 is A, the coil spring load is W ′, and the pressure increase due to the volume change of the cylinder chamber 7 is Δp [kPa], the balanced condition is [pA = W ′ + ΔpA]. . As can be seen from this condition, in order to balance with a larger water pressure, it is necessary to increase the spring load or increase the pressure change in the cylinder chamber 7.

If the spring load is increased in order to balance with a larger water pressure, there is a problem that the water hammer cannot be absorbed when the water pressure is low, and there is a constraint due to the allowable stress and space. Therefore, the pressure change in the cylinder chamber 7 is to be increased, and the method will be examined. The volume change when the piston 3 moves by the stroke L changes from V ₁ to V ₂ and pV is constant, so the pressure change is from [p ₁ V ₁ = p ₂ V ₂ ] to [p ₁ V ₁ = p ₂ V ₂ ].
₂ / p ₁ = V ₁ / V ₂ ], and it can be seen that the smaller V ₂ is, the larger Δp can be made and the larger water pressure can be balanced. Therefore, it is considered to fill the dead space (here, the cylinder volume V ₂ ) as a means for increasing the pressure change.

In the cylinder chamber 7 surrounded by the cylinder 2, the piston 3 and the plug 4 in FIG. 1, in addition to the coil spring 5 and gas, "solid" which fills the dead space is enclosed, or "solid + liquid (semi-solid)". ) ”Is included. For example, air is used as a gas, a round bar (cylindrical body) 33 made of metal, rubber, plastic or the like is used as a solid, and oil, grease, water, semisolid grease or the like is used as a liquid. The outer diameter of the coil spring 5 is smaller than the inner diameter of the piston 3 and the plug 4, and the outer diameter of the round bar 33 is smaller than the inner diameter of the coil spring 5. As shown in FIG. Reciprocally insert into the inside diameter of. The length of the round bar 33 is set when the tip of the cylindrical portion 27 of the piston 3 and the tip of the cylindrical portion 26 of the plug 4 come into contact with each other (see FIG. 1).
(See (c)), the distance between the inner surface of the piston 3 and the inner surface of the plug 4 is equal to or shorter than the distance. The end portion of the round rod 33 may be fixed to the cylinder chamber 7 side of the piston 3 or the plug 4, or the round rod 33 may be formed integrally with the piston 3 or the plug 4, respectively. Then, the outer diameter and the length of the round bar 33 are set to a length that exhibits the optimum water hammer absorption performance.

When the hydrodynamic pressure of the water supply pipe is transmitted through the through hole 6 and the hydrodynamic pressure pA exceeds the set load of the coil spring 5, the piston 3 moves and the above [pA = W '+
The piston 3 stops at a position where ΔpA] is satisfied (for example, FIG. 1 (b)). At this time, the air (gas) in the cylinder chamber 7 is compressed, and the volume changes as the pressure rises, but the round bar 33 and the liquid (semi-solid) are hardly compressed, and the allowable stress of the coil spring 5 or the close contact length causes Cylinder chamber 7
Fill the dead space inside. Therefore, the cylinder volume change rate V ₁ ′ / V ₂ can be made large, and good water hammer absorption performance can be obtained even when the dynamic water pressure is high. If lubricating oil is used as the liquid sealed in the cylinder chamber 7, the durability of the O-ring 28 mounted on the cylindrical portion 27 of the piston 3 is improved.

FIG. 2 shows a test result in which "air + solid" or "air + solid + liquid" is enclosed in the cylinder chamber 7. The test conditions were V ₁ = 16.1 cc and V ₂ = 5.3.
cc, spring load = 8.8 Kgf, cylinder diameter =
It was set to 25 mm. Then, 20 liters of water was made to flow through the water supply pipe every minute, and the pressure acting on the inner wall of the water supply pipe at that time was called the hydrodynamic pressure, and the hydrodynamic pressure was taken on the horizontal axis of FIG. Next, when the water faucet (faucet) was rapidly closed, the maximum value of the pressure acting on the inner wall of the water supply pipe was called the maximum water hammer pressure, and the maximum water hammer pressure was taken on the vertical axis of FIG. Although the scale is omitted in FIG. 2, the test results show that when the water hammer absorber 1 with water enclosed is used as compared with the conventional water hammer absorber 1 without water enclosure. The maximum water hammer pressure decreased in the range of dynamic water pressure of about 0.2 MPa or more.

3 (a) and 3 (b) show a second embodiment of the water hammer absorber 1 of the present invention. The second embodiment is arranged in series in the water supply pipe so that water flows outside the cylinder 38 of the water hammer absorber 1 so that the appearance of the water hammer absorber 1 is improved. The water hammer absorber 1 has a cylindrical housing 35, and the female screw at one end (the right end in FIG. 3) of the housing 35 has a second connecting fitting.
A male screw on the outer surface of the large diameter portion of 49 is screwed, and an O-ring 50 seals between the housing 35 and the large diameter portion of the second connection fitting 49. A male screw on the outer surface of the large diameter portion of the first connection fitting 36 is screwed into a female screw at the other end of the housing 35 (the left end in FIG. 3), and O is provided between the housing 35 and the large diameter portion of the first connection fitting 36.
Sealed by ring 37. The first through hole 46 on the other end side of the first connection fitting 36 is communicated with a water supply source, for example, via a water supply pipe, and the second through hole 47 on the one end (right end in FIG. 3) side of the second connection fitting 49 is, for example, It communicates with a faucet through a water supply pipe.

A substantially cylindrical cylinder 38 is disposed inside the housing 35, and a male screw of a cylindrical portion 41 of a cup-shaped plug 39 is screwed into a female screw of the other end (left end in FIG. 3) of the cylinder 38. . A piston 3 having a U-shaped cross section is slidably fitted in the cylinder 38, and a coil spring 5 is interposed in a cylinder chamber 7 between the piston 3 and a bottom portion 40 of the plug 39. As a result, the piston 3 is biased toward one end. Cylindrical portion 27 of piston 3 and cylindrical portion 41 of plug 39
Are located opposite to each other, and an O-ring 51 is attached to an annular groove on the outer peripheral surface of the cylindrical portion 41 of the plug 39, and the O-ring 51 seals between the plug 39 and the cylinder 38. There are three annular grooves on the outer peripheral surface of the cylindrical portion 27 of the piston 3, and O-rings 28 are attached to these annular grooves, respectively.
The space between the cylindrical portion 27 of the piston 3 and the cylinder 38 is sealed watertight by the 28. An annular contact surface 31 is formed at one end of the inner surface of the cylinder 38 and serves as a stopper for the piston 3.
A male screw on the outer peripheral surface on one end side of the small diameter portion 43 on one end side of the cylinder 38 is screwed into a female screw on the small diameter portion 44 of the second connection fitting 49,
A plurality of communication holes 42 are formed in the cylindrical small diameter portion 43.
The first through hole 46 is a gap between the housing 35 and the cylinder 38.
It communicates with the 2nd through-hole 47 through 45 and the communicating hole 42.

In the second embodiment as well, as in the first embodiment, the cylinder chamber 7 surrounded by the cylinder 38, the piston 3 and the plug 39 fills a dead space in addition to the coil spring 5 and gas. Round bar 33) "is enclosed,
Alternatively, "solid + liquid (including semi-solid)" is enclosed. When the faucet is opened, the water sent from the water supply source is supplied from the water supply pipe to the first through hole 46, the gap 45, the communication hole 42, and the second through hole 4 of the water hammer absorber 1.
7. Flow toward the faucet through the water pipe. The dynamic water pressure of the water supply pipe is changed by the operation of the water faucet, and the change is transmitted to the pressure receiving surface 32 of the piston 3 facing the communication hole 42. Hydraulic pressure p
When A exceeds the set load of the coil spring 5, the piston 3 moves to the left in FIG. 3 due to the water hammer pressure in the direction opposite to the water flow, and the piston 3 is moved to the position where the above [pA = W '+ ΔpA] is satisfied. Stop. At this time, the air (gas) in the cylinder chamber 7 is compressed, and its volume changes as the pressure rises, but solids and liquids (semi-solids) are hardly compressed, and the dead space created by the allowable stress or the contact length of the spring is filled. . Therefore, the cylinder volume change rate V ₁ ′ / V ₂ can be made large, and good water hammer absorption performance can be obtained even when the dynamic water pressure is high. The other points are the same as in the first embodiment.

[0018]

According to the present invention, the gas chamber and the "solid" or "solid and liquid" for filling the dead space are enclosed in the cylinder chamber of the water hammer absorber. Since the solid or liquid fills the dead space created by the allowable stress of the coil spring and the contact length of the coil spring, the rate of change in cylinder volume in the cylinder chamber can be increased. Therefore, even if the dynamic water pressure in the pipe communicating with the water hammer absorber increases, the water hammer absorbing performance can be sufficiently exhibited without replacing the coil spring. Then, the amount of solid or liquid sealed in the cylinder chamber can be adjusted according to the dynamic water pressure in the pipe, and the optimum water hammer absorption performance can be exhibited.
And when solid and liquid are enclosed in the cylinder chamber,
By the action of the liquid, it is possible to prevent rattling noise that is generated when the solid comes into contact with the coil spring or the like. Further, when a lubricant is used as the liquid for filling the dead space, the durability of the O-ring mounted on the piston can be improved by the action of the lubricant. According to the present invention, the second through hole is formed on one end side of the housing, and the first through hole is formed on the other end side of the housing, the cylinder is arranged in the housing with a predetermined gap, and the pressure receiving surface of the piston is A water hammer absorber can be provided in which the first through hole and the second through hole are directed toward the two through hole side and communicate with each other through a gap. In this case, connect the water hammer absorber in series in the middle of the pipe and install it as easily as connecting the pipes.The water hammer absorber has a cylindrical shape with a slightly larger diameter than the pipe. Yes, it does not require space for a water hammer absorber.

[Brief description of drawings]

FIG. 1 is a sectional view showing a first embodiment of a water hammer absorber of the present invention.

FIG. 2 is a diagram showing test results of the first embodiment of the water hammer absorber of the present invention.

FIG. 3 is a sectional view showing a second embodiment of the water hammer absorber of the present invention.

FIG. 4 is a schematic view showing a usage state of the water hammer absorber.

FIG. 5 is a sectional view showing a conventional water hammer absorber.

[Explanation of symbols]

1 water hammer absorber 2 cylinders 3 pistons 4 plugs 5 coil spring 6 through holes 7 cylinder chamber 26 Cylindrical part 27 Cylindrical part 30 O-ring 32 Pressure receiving surface 33 Round bar (cylindrical body) 35 housing 38 cylinders 39 plug 41 Cylindrical part 42 communication hole 43 Small diameter part 45 Gap 46 First through hole 47 Second hole 49 Second connection fitting 51 O-ring

Continuation of the front page (56) References JP-A-2-134490 (JP, A) JP-A-3-272378 (JP, A) Actual Development Sho 61-193288 (JP, U) Actual Public Sho-39-21680 (JP , Y1) (58) Fields investigated (Int.Cl. ⁷ , DB name) F16L 55/02-55/045

Claims (12)

(57) [Claims] 1. A piston is slidably and watertightly fitted in a cylinder, a coil spring is arranged to bias the piston toward one end of the cylinder, and the coil spring is arranged in the cylinder. In a water hammer absorber in which the inside of the piston is used as a cylinder chamber and the pressure receiving surface on the outside of the piston communicates with a pipe through a hole, the cylinder chamber is filled with gas and solids for filling dead spaces. A water hammer absorber characterized by that. 2. A piston is slidably and watertightly fitted in a cylinder, a coil spring is arranged to bias the piston toward one end of the cylinder, and the coil spring is arranged in the cylinder. In a water hammer absorber in which the inside of the piston is used as a cylinder chamber and the pressure receiving surface on the outside of the piston is communicated with the pipe through a hole, solid and liquid for filling gas and dead space are filled in the cylinder chamber. A water hammer absorber characterized by being enclosed. 3. The water hammer absorber according to claim 1, wherein a cylindrical solid is inserted into the inner diameter of the coil spring as the solid for filling the dead space. 4. The water hammer absorber according to claim 1, wherein an outer diameter of the cylindrical solid for filling the dead space is smaller than an inner diameter of the coil spring. 5. The cylinder part of the cup-shaped plug is screwed to the other end of the cylinder, the space between the cylinder and the cylinder part of the plug is sealed by an O-ring, and the other end of the spring is supported by the plug. The water hammer absorber according to any one of claims 1 to 4. 6. The water hammer absorber according to claim 1, wherein the outer diameter of the coil spring is smaller than the inner diameter of the cylindrical portion of the piston and the inner diameter of the cylindrical portion of the plug. 7. The water hammer absorber according to claim 1, wherein a cylindrical solid body for filling the dead space is fixed inside the cylinder or inside the cup-shaped plug. 8. The water hammer absorber according to claim 7, wherein a cylindrical solid body for filling the dead space is integrated with a cylinder or a cup-shaped plug. 9. The length of the cylindrical solid for filling the dead space is the inner surface of the piston and the inner surface of the plug when the tip of the cylindrical portion of the piston and the tip of the cylindrical portion of the plug contact each other. The water hammer absorber according to any one of claims 1 to 8, which has a length equal to or shorter than the distance. 10. The water hammer absorber according to claim 1, wherein a lubricant is filled as the liquid for filling the dead space. 11. A second through hole is formed on one end side of the housing, and a first through hole is formed on the other end side of the housing. A cylinder is arranged in the housing with a predetermined gap, and a pressure receiving surface of the piston is provided. The water hammer absorber according to claim 1, wherein the water hammer absorber is directed toward the second through hole side, and the first through hole and the second through hole communicate with each other through a gap. 12. A male screw of a small diameter portion of the second connecting fitting is screwed to a male screw of a small diameter portion of one end of the cylinder, and a male screw of a cylindrical portion of the second connecting fitting is screwed to a female screw at one end of the housing. 12. The water hammer absorber according to claim 1, wherein a communication hole is formed in a small diameter portion on one end side of the cylinder, and the first communication hole is communicated with the second communication hole through a gap and the communication hole.