JPH07158127A - Water hammer-prevention device - Google Patents

Abstract

PURPOSE:To absorb water hammer occurring in the case of quick cut-off of a pipe line to provide a water hammer-prevention device for protecting equipments connected to a pipe or the pipe line and to promote water supply capacity reducing the pressure loss of running water by the water hammer- prevention device. CONSTITUTION:A pressure absorption chamber 4 is formed in the outside of a venturi tube 1 provided to a pipe line, and a connection hole 13 is opened in a throttle section 12 of the venturi tube 1 to connect the pressure absorption chamber 4 to the inside of the venturi tube 1. With the movement of a flow hinderer 17 pushed down to a lower stream side 11 by the force of water, it is elastically energized toward an upper stream side 10 and is placed to the inside of the venturi tube 1 so that the channel area of the throttle section 12 can be enlarged.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water hammer prevention device for absorbing water hammer generated when a pipeline is suddenly shut off and protecting equipment connected to the piping and the pipeline.

[0002]

2. Description of the Related Art In recent years, a faucet device for general households has a single-lever mixing tap, a shower with an intermediate water stop, a mixing tap with a spout switching device, or a button operation to stop the water from the viewpoint of improving operability. There is an increasing number of devices such as faucets with a solenoid valve that can easily shut off the pipeline easily. By the way, when the pipeline is suddenly shut off, a sudden pressure rise occurs due to the momentum of the water flow, which is one of the causes of damage to the pipes and equipment connected to the pipeline as a so-called water hammer. .

Various water hammer prevention devices for preventing this have hitherto been devised. FIG. 7 shows an example thereof disclosed in Japanese Utility Model Laid-Open No. 1-79662. This is because a small communication port d communicating with the pressure absorption chamber c is opened in the throttle portion (throat portion) b of the Venturi tube a provided in the pipe line, and a check valve for introducing the atmosphere into the pressure absorption chamber c is provided. The valve e is provided, and the water in the pressure absorbing chamber c is absorbed from the communication port d by the pressure drop due to the Venturi action of the water flowing through the throttle portion b, and at the same time, the pressure absorbing chamber c is externally supplied through the check valve e. When the secondary side conduit of the Venturi tube a is suddenly shut off and the pressure is rapidly increased, the water in the Venturi tube a flows into the pressure absorption chamber c through the communication port d, and its kinetic energy is absorbed. It is what is done.
That is, since the water in the pipe passes through the small-diameter communication port d at an extremely high speed and then enters the pressure absorption chamber c, the kinetic energy disappears and the water hammer is absorbed due to the rapid expansion of the cross-sectional area at that time. . Note that here, the atmosphere in the pressure absorption chamber c is the check valve e.
Since it is not discharged to the outside, it is compressed by water pressure and its elasticity also absorbs the water hammer.

[0004]

However, in such a conventional water hammer prevention device, there is a problem that the water supply capacity becomes low because the pressure loss due to passing through the Venturi tube is very large. That is, in the above water hammer prevention device, it is necessary to absorb the atmosphere into the pressure absorption chamber c through the check valve e so that the water pressure in the throttle portion b of the venturi pipe a can be lower than the atmospheric pressure. In this case, since the throttle portion b must be sufficiently throttled to sufficiently increase the flow velocity, there is a problem that the pressure loss becomes large and the maximum water supply capacity also decreases.

[0005]

DISCLOSURE OF THE INVENTION The present invention is intended to solve the above-mentioned problems. A pressure absorbing chamber is formed outside a venturi pipe provided in a pipe line, and a communication hole is formed in a throttle portion of the venturi pipe. It is opened to connect the inside of the Venturi tube with the pressure absorption chamber, and the upstream side so that the flow passage area of the throttle portion can be expanded as the obstacle fluid is pushed to the downstream side by the hydraulic force and moves in the Venturi tube. It is characterized in that it is arranged so as to be elastically biased toward.

[0006]

[Function] Since the obstacle fluid is moved by the water force, the flow passage area is expanded to reduce the pressure loss and increase the flow rate, so that the water supply capacity is high. Also, when the flow rate is low, the water flow is small and the flow path area is kept small by the impeding fluid.Therefore, even when the flow rate is low, the flow velocity in the throttle can be kept high and water can be sucked from the pressure absorption chamber. A pressure drop can be obtained. Therefore, a sufficient water hammer prevention capability can be obtained from a large flow rate to a small flow rate.

[0007]

EXAMPLE An example of the present invention will be described with reference to FIGS. In the figure, reference numeral 1 denotes a Venturi tube integrally formed with a tube portion 2 at one end, and 3 denotes an externally fitted and screwed integrally with the Venturi tube 1 so that a pressure absorption chamber 4 is formed around the Venturi tube 1. This is a combined cylindrical body, and the check valve 5 is integrally provided on the body 3. Numerals 6 and 7 are seal members arranged for water-tightly connecting the outer circumferences of both ends of the Venturi tube 1 and the inside of the body 3. Also, 8
Is an upstream pipe line (not shown) attached to one end of the pipe portion 2.
A cap nut 9 for connecting to the outer peripheral portion of the body 3 is a screw groove formed on the outer periphery of the other end of the body 3 for connecting a downstream pipe line (not shown). Water flows through the Venturi tube 1 from the upstream side 10 toward the downstream side 11 as shown by the white arrow.

A throttle portion (throat portion) 12 of the Venturi tube 1
Four small communication holes 13 communicating with the pressure absorption chamber 4 are formed around the. Reference numeral 14 is an annular guide member fixedly provided on the inner wall of the upstream side 10 of the Venturi pipe 1. The guide member 14 has a guide hole 15 formed in the center thereof, and a fan-shaped water passage hole 16 is formed around the guide hole 15. Has a large opening so as not to get in the way of water flow. Reference numeral 17 denotes a conical fluid which is formed in a conical shape, and a collar-shaped stopper 18 and a straight shaft portion 19 which further extends from the collar-shaped stopper 18 are integrally formed on the smaller diameter side of the fluid. Then, by inserting the straight shaft portion 19 into the guide hole 15 slidably, the obstacle fluid 1
7 is arranged at the axial center of the Venturi tube 1 so that the small diameter side faces the upstream side 10, and a coiled spring 20 is externally inserted to the protruding portion of the straight shaft portion 19 on the upstream side 10. By fixing a washer 21 and a nut 22 to the tip of the shaft portion 19, the spring 20 is interposed in a compressed state between the guide member 14 and the washer 21, and the elasticity of the spring 20 causes the obstacle fluid 17 to move to the upstream side 10. We are pushing towards.

The check valve 5 is provided with an annular guide 24 and a tubular valve seat body 25 at the inner bottom of a short pipe portion 23 formed integrally with a part of the body 3 and an annular screw body 26 having the short length. The valve body 27 is urged by a spring 28 so that the valve body 27 is screwed into the opening of the tube portion 23 and closely contacts the tubular valve seat body 25 from the inside, so that the pressure absorption chamber 4 is lower than the atmospheric pressure. Then, the valve body 27 withdraws against the tension of the spring 28 and the outside air is introduced into the pressure absorption chamber 4.

Therefore, when the faucet is closed and water does not flow in the conduit, the obstacle fluid 17 is located on the most upstream side 10 by the elastic biasing of the spring 20, as shown in FIG. The flow passage area of the narrowed portion 12 formed by the inner peripheral surface of No. 1 and the outer peripheral surface of the obstacle 17 is minimized. At this time, the pressure absorption chamber 4 is filled with water, and the water pressure is applied to the pressure absorption chamber 4 through the communication hole 13, but the water does not flow out due to the closing of the check valve 5.

When the faucet is opened and is in a running state, the impeding fluid 17 is pushed to the downstream side 11 by the water force and the throttle portion 12
The area of the flow path is gradually expanded as shown in FIGS. At this time, when the water flow becomes faster in the throttle portion 12 and a pressure drop (venturi action) occurs and the pressure becomes lower than the atmospheric pressure, the water in the pressure absorption chamber 4 is sucked into the venturi pipe 1 through the communication hole 13. At the same time that the water in the pressure absorption chamber 4 is sucked into the Venturi tube 1, the check valve 5 opens and the pressure absorption chamber 4
The atmosphere is replenished to.

Then, when the faucet is suddenly closed and the water flow is suddenly cut off, the water pressure in the pipe line rises sharply and the water pressure in the throttle portion 12 of the Venturi pipe 1 becomes higher than atmospheric pressure. Water flows into the pressure absorption chamber 4 through the communication hole 13 and its kinetic energy is absorbed. That is, the water in the Venturi tube 1 flows into the pressure absorption chamber 4 after passing through the small-diameter communication holes 13 at a very high degree and then flows into the pressure absorption chamber 4, so that the kinetic energy disappears and the water hammer is absorbed by the rapid expansion of the cross-sectional area. . At this time, the atmosphere in the pressure absorption chamber 4 is not discharged to the outside from the check valve 5, so it is compressed in the pressure absorption chamber 4 and the elasticity of the air absorbs the kinetic energy to eliminate the water hammer.

In the above embodiment, the check valve 5 is provided in the pressure absorption chamber 4 so that the outside air can be sucked into the pressure absorption chamber 4, but the pressure absorption chamber 4 does not necessarily have this structure. As shown in the example, the check valve 5 may not be provided. For example, as shown in FIG. 6, the pressure absorption chamber 4 is hermetically closed to cause cavitation by the negative pressure generated by the Venturi action, and the cavitation bubbles are It is also possible to introduce the water hammer into the pressure absorption chamber 4 and absorb the water hammer by the air accumulated in the pressure absorption chamber 4. Alternatively, an elastic body (a bag-like object in which air, nitrogen gas, etc. are enclosed, or a chamber surrounded by an elastic diaphragm, etc.) that expands and contracts due to pressure is provided in the closed pressure absorption chamber 4, and the expansion and contraction thereof. By utilizing the action, water can be made to flow into the pressure absorption chamber 4 to absorb the impact as in the above-described embodiment.

Further, the obstacle fluid 17 is not limited to the conical shape as shown in the embodiment, but may be any other shape as long as the outer diameter gradually increases toward the downstream side. In addition, the water hammer prevention device shown in the embodiment is of a type that is inserted between the pipe and the faucet, but in addition to this, when inserted in the middle of the pipeline, when incorporated in the faucet, Alternatively, the same operation can be performed when it is incorporated into other fluid control equipment.

As described above, in the water hammer prevention device of the present invention, the impeding fluid is moved by the water force of the water passing through the Venturi tube so that the flow passage area of the throttle portion is enlarged, so that the pressure loss is small and the water flow is always maintained. High water supply capacity is secured. Moreover, since the impeding fluid is urged toward the upstream side, the flow passage area of the throttle portion naturally narrows when the flow rate is low, and the pressure required to suck water from the pressure absorption chamber even when the flow rate is low. Since the descent is obtained in the throttle portion, there is a beneficial effect such that the water hammer prevention function is fully exerted regardless of the flow rate.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of a water hammer prevention device according to the present invention.

FIG. 2 is a sectional view taken along the line AA of FIG.

FIG. 3 is a sectional view taken along line BB of FIG.

FIG. 4 is an operation state diagram of FIG. 1.

5 is an operation state diagram of FIG. 1. FIG.

FIG. 6 is a vertical sectional view of a water hammer prevention device showing another embodiment of the present invention.

FIG. 7 is a vertical cross-sectional view of a conventional water hammer prevention device.

[Explanation of symbols]

 1 Venturi pipe 4 Pressure absorption chamber 5 Check valve 10 Upstream side 11 Downstream side 12 Throttling part 13 Communication hole 14 Guide member 17 Obstacle fluid 20 Spring

Claims (1)

[Claims] 1. A pressure absorbing chamber is formed outside a Venturi pipe provided in a pipe line, and a communication hole is formed in a throttle portion of the Venturi pipe to communicate the inside of the Venturi pipe with the pressure absorbing chamber. The obstacle fluid is elastically urged toward the upstream side in the Venturi tube so that the flow passage area of the throttle portion can be expanded as the obstacle fluid is pushed and moved to the downstream side by the hydraulic force. Characteristic water hammer prevention device.