JPS62270881A - Noise control method of pump piping - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention [Object of the Invention] "Field of Industrial Application" The present invention relates to a noise prevention method based on vibration of a pump discharge pipe.

"Problems to be solved by conventional technology and invention" Conventionally,
The pump water pipe supports the weight of the water pipe and the liquid to be handled, and the water pipe is fixed to an immovable part of the ground ring by a support member in order to prevent thrust caused by discharged water. In addition to the above-mentioned support for water pipes, it is also considered to prevent vibrations of the water pipes due to vibrations of flowing water occurring in the water pipes.

Conventionally, in order to stop the vibration of water pipes, they are supported with a support part with a sufficiently large mass, but this is not necessarily done without giving sufficient consideration to the mode of vibration of water pipes, so it is necessary to firmly fix the parts of the pipe that have large vibrations. Although the vibration of the water pipe is suppressed, it propagates through the supporting member of the water pipe and becomes solid-borne sound. In order to prevent solid-borne sound from pump piping, it is desirable to prevent the piping from coming into contact with walls or floors. However, the pump piping has problems with thrust loads,
From the perspective of earthquake countermeasures, it is necessary to securely fix the structure.

SUMMARY OF THE INVENTION An object of the present invention is to provide a noise prevention method for pump piping in which solid-borne noise is less likely to occur, by solving the above-mentioned problems with conventional pump piping.

[Structure of the invention]

``Means for solving the problem'' A standing wave is generated in the water pipe by the pressure pulsating waves of the water discharged from the pump. The magnitude of the wall vibration of the water pipe corresponds to the magnitude of the standing wave, with the maximum at the antinodes of the standing waves and the minimum at the nodes. When fixing a water pipe, it should be fixed at the point where the vibration is the greatest. This fixation is performed via a cushioning material.

"Example" Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a side view. A discharge port 3 of a pump 2 firmly fixed on a pump foundation 1 provided on the floor is connected to a water pipe 6 via a reverse valve 4 and a gate valve 5. The water pipe 6 passes through the wall 7 of the building, exits outdoors, bends at a right angle at an outdoor bent pipe 8, and continues the water pipe. Indoors, this water pipe 6 is supported by a concrete-wrapped indoor support part 9 on a foundation set on the floor, a support wall part 11 by the wall 7, and a bent pipe part 8 supported by a bent pipe support part 12 on a foundation set on the ground. ing. Pump basics 1
In order to firmly support the pump 2 and the water pipe 6, the bent pipe support part 12 is made of concrete so as to have a sufficiently large mass. And it is designed to receive pump thrust.

The two indoor support parts 9 and the support wall part 11 are made of concrete, and cushioning materials 10 and 13 such as rubber and elastomer are interposed between the water pipe 6 and the concrete support members, respectively.

In the above, the distance L1 between the discharge port 3 of the pump 2 and the intermediate point 21 of the two indoor supports, the distance L2 between the intermediate point P1 and the center of the wall 7, and the distance between the center of the wall 7 and the center of the bent pipe 8 are L3
Then, L1=L2=L3=L, which means that they are equally spaced.

And each indoor support part 9 is spaced 11. It is located at the center of each of L2.

Based on the pressure pulsation wave of the water discharged from the pump 2, two waves having the same period and wavelength and the same vibration surface propagate in opposite directions along the same path. Suppose that the vehicle is moving through the water pipe 6. The phases of the vibrations at the points where they occur generally differ depending on each component wave, but there are bound to be places where they are exactly the same. Moreover, the true position exists for each distance of wavelength λ. Taking such a position as the origin of the coordinate axes, in the photographing plane of each component wave, the longitudinal direction of water pipe B is set as the X axis, and the water pipe 6 is
(If yM is taken perpendicularly to this, the equation of the component wave becomes y1=A 8in 2g , , -, di. However,
T is the period, t is the time, and since it is an hour wheel here, the amplitudes of the component waves are equal to A. According to the above formula, the equation of interference wave is 7 = 7' + 72 = 2 A C0r3TX-8i
It becomes n-1-t +21.

This represents a standing wave, where at the nodes the amplitude is least, but the change in density and therefore pressure is most significant. However, at the antinode, the amplitude is maximum, but the change in density and therefore pressure is minimum. In this case, the waveform of the interference wave does not move forward, but merely oscillates at the same location with a known amplitude. The magnitude of the pipe wall vibration of the water pipe 6 corresponds to the magnitude of the standing wave. Since a thrust load is applied to the water pipe 6 due to the pumping action of the pump 2, it must be firmly fixed, and it is also required to be firmly fixed for earthquake countermeasures. However, it is not necessary that the whole thing be strongly supported,
The pump thrust may be supported by the pump foundation 1 and the bent pipe support portion 12. Since this part is a node (including the beginning) of a standing wave, solid-borne sound is thereby minimized. If L=1/2 is selected here, the indoor support portion 9 will be located at the antinode of the standing wave. Since the indoor support part 9 is a concrete structure having a sufficiently large mass, mechanical vibrations of the water pipe 6 can be attenuated. The micro vibrations that become solid-borne sound are caused by the buffer material 10.
Since the sound is absorbed by the concrete part of the indoor support part 9 and is not transmitted to the concrete part of the indoor support part 9, noise due to structure-borne sound does not occur.

Incidentally, since the pump support part 1 and the bent pipe support part 12 are at the position where the amplitude of the standing wave is zero, solid-borne sound is unlikely to occur. The supporting wall portion 7 is a node of a standing wave, and since the wall 7 is likely to generate solid-borne sound, a buffer material 13 is provided.

〔Effect of the invention〕

The present invention deals with noise caused by pump piping, which is characterized by fixing the top of the water supply pipe communicating with the pump with a support part via a buffer material in response to pressure pulsating waves of pump discharge water (the antinodes of standing waves caused by this). Since this prevention method is adopted, noise in the pump piping caused by pressure pulsating waves of pump discharge water can be prevented.

[Brief explanation of drawings]

FIG. 1 is a side view of an embodiment of the invention. 1. Pump foundation 2. Pump 3. Discharge port 4.
・Return valve 6・・Water pipe 7・・Wall 8・・Bent pipe 9・
・Indoor support part 10...Buffer material 11...Support wall part 1
2. Bent pipe support part 16. Cushioning material.

Claims (1)

[Claims] 1. A method for preventing noise in pump piping, characterized in that the top of the water pipe communicating with the pump is fixed with a support part via a cushioning material in response to the antinode of a standing wave caused by pressure pulsating waves of pump discharge water. .