JPH0552491U - Water hammer prevention device and manufacturing method thereof - Google Patents

Abstract

(57) [Summary] (Correction) [Purpose] A compact structure that reduces the heat load on the packing by eliminating the parts that are thermally joined after the piston is fitted, has few parts with risk of leakage, and is easy to manufacture. Propose a water hammer stop. Moreover, the manufacturing method is proposed. [Structure] Bottomed cylindrical pressure vessel 11 and this pressure vessel 11
In a water hammer preventer having a piston 12 slidably fitted in and containing a gas of a predetermined pressure, the bottom of the pressure vessel 11 is constituted by a closed bottom formed before the piston 12 is fitted, and The piston 1 is attached to the open end of the pressure vessel 11.
2) A reduced diameter portion 11C formed after fitting is provided. In addition, a connection member is provided at the open end of the pressure vessel 11 that has a portion smaller than the diameter of the piston 12 and that is screwed into the open end of the pressure vessel 11 after the piston 12 is fitted.

Description

[Detailed description of the device]

[0001]

[Industrial application]

 The present invention mainly relates to a water hammer preventive device which is attached to a water supply pipe and a hot water supply pipe in the vicinity of an end device to absorb and mitigate a water hammer generated by the end device, and a manufacturing method thereof.

[0002]

[Prior Art]

 Conventionally, as this type of water hammer preventer, as shown in FIG. 11, for example, a connecting member (b) is connected to one end of a cylinder (a) and a cylinder cap (c) with a valve (e) is connected to the other end. It is known that the piston (d) is slidably inserted into the pressure container formed by filling the cylinder cap (c) side of the piston (d) with gas of a predetermined pressure, and the connecting member (b) When the pipe is connected to the branch portion of the pipe, the water hammer acts on the pressure receiving surface of the piston (d), and the piston (d) compresses the gas to absorb and reduce the energy of the water hammer. In this water hammer preventer manufacturing method, first, the piston (d) is fitted into the cylinder (a), then the connecting member (b) is fitted into the cylinder (a), and the cylinder cap ( C) is fitted and soldered, compressed gas is injected from the valve (e), and finally the valve cap (f) for leak prevention is fitted to the cylinder cap (c).

Further, as an example of a water hammer preventer having the same function, as shown in FIG. 12, a connecting member (i) is connected to one end of a cylinder (h) and the other end is subjected to closing or soldering. It is also known that a piston (l) is slidably fitted in a pressure container formed by the above, and a gas of a predetermined pressure is sealed on the closing part (n) side of the piston (l). This water hammer protector is manufactured by first fitting the connecting member (i) to the cylinder (h) and then soldering it, and then inserting the piston (l) into the cylinder (h) in an atmosphere of compressed gas. The last step is closing or soldering while maintaining the pressure.

[0004]

However, in the former prior art, since the heat-bonded portions are located at two ends of the cylinder (a), the packing (g) of the piston (d) is deteriorated due to the heat load during manufacturing. There is In addition, since the number of parts is large and the number of manufacturing processes is large, the cost is high. Furthermore, it is difficult to maintain the initial performance because the enclosed gas may leak from the three soldering points and the valve (e) at three points. In addition, the cylinder cap (c) with the valve (e) and the connecting member (b) increase the total length of the water hammer preventer.

Further, in the latter prior art, the work is difficult because it is closed or soldered in an atmosphere of compressed gas, and when such a work with a high heat load is performed, it is similar to the former prior art. The packing is easily deteriorated by high heat load.

The present invention was made by paying attention to the manufacturing process of the water hammer preventer, and the purpose thereof is to reduce the heat load on the packing by eliminating the portion to be thermally joined after the piston is fitted. The aim is to propose a compact water hammer preventer with a structure that has few parts for leakage and is easy to manufacture with few parts, and to propose the most suitable method for manufacturing the water hammer preventer. There is.

[0007]

[Means for Solving the Problems]

 In order to achieve the above object, the water hammer preventer according to claim 1 has a bottomed cylindrical pressure vessel and a piston slidably fitted in the pressure vessel, and encloses gas at a predetermined pressure. Assuming a water hammer preventer, the bottom of the pressure vessel has a close-closed bottom formed before the piston is inserted, and the open end of the pressure vessel has a reduced diameter portion formed after the piston is inserted. It has a structure.

The water hammer preventer according to claim 2 is the water hammer preventer according to claim 1, wherein the diameter reducing portion is provided at the open end of the pressure container, and It has a small portion and is provided with a connecting member that is screwed into the open end of the pressure vessel after the piston is fitted.

Further, the manufacturing method of claim 3 is the method of manufacturing the water hammer preventer according to claim 1 or 2, wherein the pressure container is airtightly connected to the tip of the guide cylinder at its open end, and The piston is fitted into the guide cylinder under atmospheric pressure, and after the piston enters the pressure container, the open end of the pressure container is finally processed.

The manufacturing method according to claim 4 is the method for manufacturing a water hammer preventer according to claim 2, wherein the piston is fitted in the pressure vessel in an atmosphere of compressed gas, and then the open end of the pressure vessel is inserted. The connecting member is screwed.

[0011]

[Action]

 In the structure of claim 1, there is no place to be thermally joined after the piston is fitted, so there is no fear of deterioration of the packing due to heat load. Further, since it can be configured only with the pressure vessel and the piston, the number of parts is small and the number of manufacturing steps is also small. Moreover, it is possible to limit the location where the enclosed gas can leak only to the piston sliding portion. The total length of the water hammer prevention device is determined by the length of the pressure vessel.

According to the second aspect of the present invention, since there is no part to be thermally joined after the piston is fitted, there is no fear of deterioration of the packing due to heat load. Further, since it can be configured only with the pressure vessel, the piston and the connecting material, the number of parts is small and the number of manufacturing steps is also small. Moreover, it is possible to leak the enclosed gas only to the piston sliding portion and the connecting member screwing portion. The total length of the water hammer prevention device is determined by the length of the pressure vessel and the protruding amount of the connecting member.

According to the third aspect of the present invention, the gas is compressed from the atmospheric pressure to a predetermined pressure by the work of inserting the piston into the guide cylinder, and the gas is sealed in the pressure container. In this manufacturing method, the work always proceeds under atmospheric pressure, and there are no steps that require thermal bonding, and the only working step is the caulking step or the tightening step.

According to the structure of claim 4, there is no step requiring thermal bonding, and the processing step is only the tightening step.

[0015]

【Example】

 Examples will be described below. FIG. 1 shows a water hammer preventer according to the first embodiment. In the figure, reference numeral 11 denotes a bottomed cylindrical pressure vessel, which is a cylinder 11a and a cylinder that is hermetically coupled to one end of the cylinder 11a by brazing to form a closed bottom of the pressure vessel 11. It consists of a cap 11b. A male screw is formed on the outer peripheral portion of the cylinder cap 11b. A piston 12 is slidably fitted into the pressure container 11, and a gas of a predetermined pressure is sealed by the cylinder 11a and the piston 12. A reduced diameter portion 11c formed by caulking after the piston is fitted is provided at the open end of the pressure vessel 11. Incidentally, 12a is a packing fitted in a groove on the outer circumference of the piston 12.

When this water hammer preventer is used, the cylinder 11a is inserted into the flow path constituent member so that the pressure receiving surface of the piston 12 faces the flow path, and the male screw of the cylinder cap 11b is screwed into the flow path constituent member. And fix it. Then, the water hammer acts on the pressure receiving surface of the piston 12, and the piston 12 compresses the gas, whereby the energy of the water hammer is absorbed and alleviated.

In the water hammer preventer of the first embodiment described above, the piston 12 is fitted into the cylinder 11a with the cylinder cap 11b already brazed, and there is no place to be thermally joined after the piston is fitted. Therefore, there is no fear that the packing 12a will be deteriorated due to the heat load during manufacturing. Further, since the water hammer protector can be constituted only by the cylinder 11a, the cylinder cap 11b and the piston 12, the number of parts is small and the number of manufacturing steps is also small. Moreover, since the sealed gas can leak only at the soldering portion of the cylinder cap 11b and the piston sliding portion, it is easy to maintain good initial performance. Further, since the portion of the cylinder cap 11b protruding from the cylinder 11a is small, the total length of the water hammer preventer is shortened and the water hammer preventer is compact.

Next, a method of manufacturing the water hammer preventer of the first embodiment will be described with reference to FIGS. In FIG. 2, reference numeral 15 is a guide cylinder, the inner diameter of which is set to be substantially the same as the outer diameter of the cylinder 11a, and a packing 15a is attached to the inner wall at one end. Further, 16 is an insertion rod, which is inserted from one end of the guide cylinder 15. First, the pressure vessel 11 is fitted and connected to the tip of the guide cylinder 15 from its open end, the piston 12 is fitted into the guide cylinder 15 under atmospheric pressure, and the insertion rod 16 is attached to this. U Then, as shown in FIG. 3, the insertion rod 16 is pushed under atmospheric pressure until the piston 12 comes out from the guide cylinder 15 and enters the pressure vessel 11, and by this work, the gas is changed from atmospheric pressure to a predetermined pressure. It is compressed and enclosed in the pressure vessel 11. Then, the open end of the pressure vessel 11 is finally processed. That is, as shown in FIG. 3, a caulking device 17 composed of a processing roller 17a and a guide roller 17b arranged to face each other forms a groove having a U-shaped cross section along the entire circumference of the cylinder 11a. As shown, the cut-off roller 18 cuts the groove in the middle to form the reduced-diameter portion 11c.

According to the above-described manufacturing method, the work proceeds all the time under atmospheric pressure, and there are no steps that require thermal bonding, and the processing steps are only the caulking step and the parting step, so the manufacturing operation is simple. Is.

Next, a second embodiment will be described with reference to FIG. In the figure, reference numeral 21 denotes a cylindrical bottomed pressure vessel, which is composed of a cylinder 21a and a bottom portion 21b integrally formed at one end of the cylinder 21a to form a closed bottom of the pressure vessel 21. A male screw is formed at the open end of 21a. A piston 22 is slidably inserted into the pressure container 21 and a gas having a predetermined pressure is sealed therein. A connecting member 23 is provided at the open end of the pressure vessel 21 and is fitted around the open end of the pressure vessel after fitting the piston and is screwed into the male screw portion of the pressure container 21 with a female screw. The member 23 is formed with a piston locking portion 23a smaller than the piston diameter. Further, an unthreaded guide portion is formed on the tip side of the female thread portion of the connecting member 23, and the guide portion is fitted to the unthreaded portion of the cylinder 21a. This complements the decrease in strength that may occur when the cylinder 21a is threaded. Reference numeral 22a is a packing fitted in a groove on the outer circumference of the piston 22.

When using this water hammer preventer, the connecting member 23 is screwed and fixed to the flow path forming member so that the pressure receiving surface of the piston 22 faces the flow path. Then, the water hammer acts on the pressure receiving surface of the piston 22 and the piston 22 compresses the gas, whereby the energy of the water hammer is absorbed and alleviated.

In the water hammer preventer of the second embodiment, the piston 22 is fitted into the integral pressure vessel 21, and there is no part to be thermally joined after fitting the piston, so that there is no heat load during manufacturing. There is no risk that the packing 22a will deteriorate. Further, since the water hammer preventer can be constituted only by the pressure vessel 21, the piston 22 and the connecting member 23, the number of parts is small and the number of manufacturing steps is also small. Moreover, since the sealed gas can leak only at the piston sliding portion and the screwing portion of the connecting member 23, it is easy to maintain good initial performance. Further, since the portion of the connecting member 23 protruding from the cylinder 21a is small, the total length of the water hammer preventer is shortened and the water hammer preventer is compact.

Next, a method of manufacturing the water hammer preventer of the second embodiment will be described with reference to FIGS. In FIG. 7, reference numeral 25 is a guide cylinder, the inner diameter of which is set to be substantially the same as the outer diameter of the cylinder 21a, and the packing 25a is attached to the inner wall at one end. An insertion rod 26 is inserted from one end of the guide cylinder 25. Reference numeral 27 is a holding member that holds and holds the cylinder 21a and the guide cylinder 25, and a rod-shaped stopper 28 is pierced through its open end so as to be slidable in the diameter direction. The guide cylinder 25 is formed with a slit for allowing the stopper 28 to escape from the tip over a predetermined length, and the insertion rod 26 is formed with a fitting hole into which the stopper 28 is fitted at an appropriate position. ing. First, the pressure vessel 21 is fitted and connected to the tip of the guide cylinder 25 from its open end, and both are held by the holding member 27. Then, as shown by the broken line in FIG. 7, the piston 22 is fitted into the guide cylinder 25 under atmospheric pressure, and the insertion rod 26 is applied to this. Then, as shown by the solid line in FIG. 7, the insertion rod 26 is pushed under atmospheric pressure until the piston 22 comes out of the guide cylinder 25 and enters the pressure vessel 21, and this work causes the gas to rise from the atmospheric pressure to a predetermined pressure. Is compressed and enclosed in the pressure vessel 21. Then, the open end of the pressure vessel 21 is finally processed. That is, as shown in FIG. 8, the stopper 28 is inserted and stopped in the insertion hole of the insertion rod 26, the guide cylinder 25 is released, and the connecting member 23 is attached to the pressure vessel 21 via the insertion rod 26 as shown in FIG. Screw together.

According to the above-described manufacturing method, the work proceeds all the time under atmospheric pressure, and there are no steps that require thermal bonding, and the processing step is only the step of tightening the connecting member 23, so the manufacturing operation is simple. is there.

Next, a modified example of the above manufacturing method will be described with reference to FIG. In the figure, reference numerals 31 and 32 denote casings that are hermetically coupled to each other and can be separated by a hydraulic actuator (not shown). The casing 32 is provided with a pressure supply port 32a, and gas is supplied to the pressure supply port 32a at a predetermined pressure. A manipulator 33 is provided so as to penetrate the casing 32, and can be moved and rotated in the axial direction. A box jig 34 is fixed to the tip of the manipulator 33. Therefore, after the pressure vessel 21 of the second embodiment is airtightly mounted on the casing 31 and the connecting member 23 is set on the box jig 34, the casings 31 and 32 are united, and then the pressure supply port 32a. When gas is supplied from, the manipulator 33 is controlled to insert the connecting member 23 into the pressure vessel 21 after a predetermined time has passed, and the screw is screwed, the gas having a predetermined pressure is sealed in the pressure vessel 21.

According to the above manufacturing method, there are no steps that require thermal bonding from beginning to end, and the processing step is only the step of tightening the connecting member 23, so the manufacturing operation is simple.

[0027]

[Effect of the device]

 As described above, in the water hammer preventer of claim 1, the bottom portion of the pressure vessel is formed of a closed bottom before the piston is fitted, and the reduced diameter portion is formed at the open end of the pressure vessel after the piston is fitted. Since it is possible to eliminate the need for thermal joints and prevent packing deterioration, the number of main parts can be reduced to a minimum of two points to reduce manufacturing man-hours and simplify costs, and there is a risk of leakage. It is possible to maintain the initial performance for a long time by reducing the amount, and to make the overall size more compact.

Further, in the water hammer preventer of the second aspect, since the open end of the pressure vessel is provided with the connecting member having a portion smaller than the piston diameter and screwed into the pressure vessel open end after the piston is fitted. As in the first aspect, effects such as packing deterioration prevention, cost reduction, long-term maintenance of initial performance, and overall compactness can be obtained.

Further, in the method for manufacturing a water hammer preventer according to claim 3, the pressure container is hermetically connected to the tip of the guide cylinder at its open end, and then the piston is attached to the guide cylinder under atmospheric pressure. Since the piston is inserted into the pressure vessel and the open end of the pressure vessel is finally processed after the piston is inserted into the pressure vessel, work is continued under atmospheric pressure throughout the process, and there is no thermal bonding step and the caulking step Since only the tightening process is required, the manufacturing work can be simplified.

In addition, in the method for manufacturing the water hammer preventer according to claim 4, the piston is fitted in the pressure vessel in an atmosphere of compressed gas, and then the connecting member is screwed to the open end of the pressure vessel. Since there is no heat bonding process and only the tightening process is the processing process, the manufacturing work can be simplified.

[Brief description of drawings]

FIG. 1 is a partially longitudinal side view of the first embodiment,

FIG. 2 is a vertical sectional side view showing a piston fitting step in the manufacturing method of the first embodiment,

FIG. 3 is a vertical sectional side view showing the caulking process.

FIG. 4 is a vertical sectional side view showing the parting process.

FIG. 5 is a vertical sectional side view showing the final step,

FIG. 6 is a partially longitudinal side view of the second embodiment,

FIG. 7 is a vertical sectional side view showing a piston fitting step in the manufacturing method of the second embodiment.

FIG. 8 is a vertical sectional side view showing the intermediate step,

FIG. 9 is a longitudinal side view showing the final step,

FIG. 10 is a partial side view in vertical section showing a modification of the manufacturing method of the second embodiment.

FIG. 11 is a partially longitudinal side view showing a conventional water hammer preventer.

FIG. 12 is a partially longitudinal side view showing another conventional water hammer preventer.

[Explanation of symbols]

 11 Pressure Vessel 11c Reduced Diameter Part 12 Piston 12a Packing 15 Guide Cylinder 21 Pressure Vessel 22 Piston 22a Packing 23 Connecting Member 25 Guide Cylinder

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Yuo Hashioka Inventor Yuichi Hashioka 2-56-1 Uramine Minami, Hirano-ku, Osaka City Tabuchi Co., Ltd.

Claims (4)

[Scope of utility model registration request] 1. A water hammer preventer having a bottomed cylindrical pressure vessel and a piston slidably fitted in the pressure vessel and enclosing a gas of a predetermined pressure in the bottom of the pressure vessel. Is composed of a closed bottom formed before the piston is fitted, and a reduced diameter portion formed after the piston is fitted is provided at the open end of the pressure vessel. 2. The water hammer preventer according to claim 1, wherein, instead of providing the reduced diameter portion at the open end of the pressure vessel, the pressure vessel has a portion smaller than the piston diameter and the pressure is reduced after the piston is fitted. A water hammer prevention device provided with a connecting member that is screwed into the open end of the container. 3. The pressure container is hermetically connected to the tip of the guide cylinder at its open end, and then the piston is fitted into the guide cylinder under atmospheric pressure, after which the piston enters the pressure container. The method for manufacturing a water hammer preventer according to claim 1 or 2, wherein the open end of the pressure vessel is finally treated with. 4. The method for manufacturing a water hammer preventer according to claim 2, wherein the piston is fitted in the pressure vessel in an atmosphere of compressed gas, and then a connecting member is screwed to the open end of the pressure vessel.