JPS6018691A - Pressure pulsation reducer - 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 [Field of Application of the Invention] The present invention relates to a pressure pulsation reducing device for piping that handles liquid.

[Background of the invention]

Generally, when pressure pulsations generated by driving a fluid machine such as a pump are transmitted to a piping system, the piping system vibrates and radiates noise. For example, in pump equipment, a pressure change occurs when the impeller blades pass through the discharge pollute inlet, which causes a pulsation of the number of blades x rotational speed, and this pulsation propagates throughout the water column in the piping, causing the piping system to All the bars vibrate to make noise.

Conventionally, various pressure pulsation reduction means have been used to cope with the occurrence of pulsation as described above.

[Purpose of the invention]

An object of the present invention is to provide a pressure pulsation reducing device that has a simple structure and can easily change the resonance frequency.

[Summary of the invention]

The present invention provides a water column in a resonance chamber provided outside a piping flow path;
The principle is that the pressure waves of the pressure pulsations in the piping flow path resonate to reduce the pressure pulsations in the piping flow path. The resonant frequency fres of the resonant chamber is given by fres -1-J,
Here, α is the propagation speed of the pressure wave, V is the volume of the resonant chamber, G is the value determined by the shape and size of the connecting passage to the resonant chamber, and is a value called conductivity. From the frequency calculation formula, by installing the entire stem in the passage between the piping flow path and the resonance chamber and making the conductivity G2 variable, the resonance frequency of the resonance chamber can be made variable, and pressure pulsations in a wide range of frequency components can be achieved. This corresponds to the reduction. In addition, by installing the resonant chamber on the outer periphery as a full-double pipe for the piping flow path, it can be installed compactly and the rigidity can be increased.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a cross-sectional view of a variable resonance frequency type pressure pulsation reducing device for liquid piping according to the present invention, and FIG. 2 is a view taken along the line A--A in FIG. 1. Piping flow path 1. and a resonance chamber 2 formed between the outer cylindrical tube 3° and the partition plate 10.

The tapered hole 4 provided in the piping flow path and the resonance control section formed by the stem 5, 6 is a stem case.

7 is a shaft sealing mechanism, 8 is an indicator attached to the stem 5, 9 is an indicator scale ring, 11 is a handle for rotating the stem 5, 12 is an air vent valve provided in the resonance chamber 2, 13
is the drain plug. It is determined by α
: Propagation speed of pressure wave V: Valley of the resonance chamber, G: Value determined by the shape and size of the resonance control part, This conductivity G, called conductivity, is determined by G = U, S: Cross-sectional area of the resonance chamber entrance (opening), L: Length of the resonance chamber entrance (opening) with terminal correction added. Here, the resonance chamber entrance part, that is,
The shape of the opening connecting the piping flow path and the resonance chamber is a tapered hole 4, and the surface facing the tapered hole 4? have,
By forming the entire resonance control section using the stem 5, the conductivity G is changed to Cif.

The mechanism for making the conductivity G variable will be explained with reference to FIGS. 3 and 4. FIG. 3 shows a state in which the tapered hole 4 provided in the piping flow path and the stem 5 are all opened to a certain value. Considering the conductivity in this state, from FIG. 3, the length of the resonant chamber inlet with terminal correction -L, the cross-sectional area of the resonant chamber inlet: S=πdc, and the conductivity G becomes G=dc. On the other hand, stem from the state shown in Figure 3? Conductivity G when moving upward to the state shown in Figure 4
' is the population length of the resonant chamber = L', and the cross-sectional area of the resonant chamber entrance = s'
= πd′c′ and G′Once′. That is,
By forming the L' resonance control section with a tapered hole 4 and a tapered stem 5, and making the stem 5 fully movable, the conductivity G can be varied steplessly.

Since the resonant frequency f res is proportional to the square root of the conductivity G, by making the conductive heavy metal variable, the resonant frequency also becomes variable.

Further, according to the present invention, as shown in FIG. 1, by moving the stem 5,
The set resonance frequency is displayed by an indicator 8 and an indicator scale 9, so that the set value of the resonance frequency can be visualized externally. The stem 5 has a fully threaded portion in the middle, and is easily movable by means of the threaded portion, a stem case 6 having a metal thread, and a handle 11.

It is clear that depending on the variable range of the resonance frequency of the present invention, it is effective to install not only a single resonance control section and a plurality of stems.

FIG. 2 is a view taken along the line A--A in FIG. 1. Directly above the resonance chamber, there is an air vent valve 12. to vent air from the resonance chamber. All are installed.

FIG. 3 shows an embodiment in which the present invention is applied to a large diameter pipe. The resonance conductivity variable mechanism is provided in the resonance chamber passage pipe 4'.

〔Effect of the invention〕

According to the present invention, it is possible to obtain a wide range of pressure pulsation reduction effects in a piping flow path in which the pressure pulsation frequency of a centrifugal pump or the like that performs rotation speed controlled rotation changes. Moreover, the pressure pulsation reducing device of the present invention does not create resistance to the wiring.

In addition, since the resonant chamber is installed as a dual-vehicle pipe for all piping channels, the structure is compact and simple, and the rigidity is improved. The resonance frequency can be easily changed using the handle, and
It also has the effect of being able to visualize the resonant frequency set by an externally installed indicator.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of a resonant frequency variable type pressure pulsation reduction device for liquid piping, Figure 2 is a view taken along the line A-A in Figure 1, and Figures 3 and 4 are FIG. 5 is a longitudinal cross-sectional view of a pressure pulsation reduction device for a variable resonance frequency type liquid pipe of a large diameter pipe. l...Piping flow path, 2...Resonance chamber, 3...Outer cylinder pipe,
4... Resonance conduction section, 4'... Resonance chamber passage, 5... Stem, 6... Stem case, 7... Shaft sealing mechanism, 8...
...Indicator, 9...Indicator scale, 1
0... Partition plate, 11... Handle, 12... Air vent valve, 13... Drain plug, 1.4-° drain valve. Figure 1 Figure 2 Roka 3 Figure 4

Claims (1)

[Claims] 1. A resonance chamber is entirely formed on the outer periphery of a piping flow path of a piping system, a passage is provided to connect the flow passage and the resonance chamber, and the area of the passage is varied to suppress the resonance of the resonance chamber. A pressure pulsation reducing device characterized by comprising a resonance control section for controlling. 2. The resonance control section includes a stem that forms the passageway into a tapered hole, has a tapered surface that fits into the tapered hole, and is movable in the axial direction of the tapered hole. A pressure pulsation reducing device according to claim 1, characterized in that: 3. The stem extends outside through the resonance chamber, and the stem of the penetrating portion and the wall of the resonance chamber are screwed together to enable axial movement. Pressure pulsation reducing device as described in Section 3. 4. Providing a handle at the end of the stem extending outside the resonance chamber to move the stem in the axial direction.
A pressure pulsation reducing device according to claim 3, characterized in that: 5. The pressure pulsation reducing device according to claim 4, wherein an indicator is attached to the stem to indicate the value of the resonance frequency depending on the amount of axial movement of the stem.