JPS58132640A - Preventing device for pulsation - Google Patents

Abstract

PURPOSE:To regulate an absorbing action of pulsation through laterial movement of a throttle plate, by installing a cylindrical pressure receptacle and a throttle means which threadedly engages the female screw of the pressure receptacle and can move in a direction of an axis thereof. CONSTITUTION:A pulsation preventing device is provided with a cylindrical pressure receptacle 1. A female screw is provided in a direction of an axis in the inner surface of the cylindrical pressure receptacle 1, and a throttle plate 2, which threadedly engages the screw, divides the inside of the pressure receptacle 1 into two chambers A and B and varies the volume of each chamber, is located. Thus, in which case, a pulsation absorbing action can be regulated by changing the volume of the chamber B through the lateral movement of the throttle plate 2.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pulsation prevention device used when statically measuring pressure by rectifying pulsating pressure that has large pressure fluctuations, such as boiler steam pressure.

A conventional screw-type pulsation prevention device is shown in FIG.

01 is an outer cylinder, and a female thread is provided in the axial direction of the cylinder.
A diaphragm adjustment screw 02 that is screwed into this is inserted.

Note that the top of the female screw is cut flat, but the threaded portion of the aperture adjustment screw 02 is a triangular screw.

A pipe joint screw 03 is provided at one end of the outer cylinder 01, and from the other end, a tightening screw and a fixing screw 0 to prevent loosening of the adjustment screw 02 are provided.
4 is screwed in. The fixing screw 04 has 1 through hole 0
5 and pipe fitting screw 06 are provided, and fixing screw 0
4 is fitted with an O cylinder or the like to prevent pressure leakage.

A pressure conduit (not shown) whose one end is connected to a steam pipe or the like and which guides the pressure to be measured is connected to the pipe joint thread 06, and a pressure gauge 07 is connected to the other pipe joint thread 03. Fluid pressure enters from the pipe joint screw 06 side, travels spirally through the screw capillary formed by the gaps between the peaks and valleys of the throttle adjustment screw 020, and reaches the pressure gauge 07.

In this case, the screw capillary serves as a diaphragm and corresponds to R and L in an electric circuit.

Therefore, the pulsation caused by the pressure wave becomes a filter circuit equivalent to an electric R2L circuit, and the pulsation is absorbed.

In conventional equipment, this value is fixed at the manufacturing stage, so
It lacks flexibility for various plants, etc. In addition, in order to increase the squeezing effect, there are methods such as enlarging the overall shape and lengthening the screw capillary section, or narrowing the cross-sectional area of the screw capillary section, but the former method results in the shape being too large. Also, the latter has drawbacks such as easy clogging, and cannot sufficiently eliminate the pulsating frequency that is desired to be eliminated.

By the way, to give an example of usage, in the case of boiler steam pressure, there is a pulsation component of 301'J'/J at a pressure of 250 Kmm, and the frequency is about 3 [I Hz].

There are coiled vibrator and orice-shaped capillaries, but the pulsating frequency cannot be effectively suppressed by shortening the constriction part or increasing the cross-sectional area of the flow path in order to prevent the above-mentioned clogging. .

The present invention eliminates these drawbacks by providing an anti-pulsation device interposed between a pressure conduit conducting fluid pressure and a pressure gauge measuring the pressure of the fluid in the same pressure conduit.
A cylindrical pressure vessel having a female thread cut in the axial direction and having a pressure conduit attached to one end and a pressure gauge attached to the other end, and a throttle plate having a throttle means that is screwed into the female thread of the pressure vessel and movable in the axial direction. It is characterized by the following.

Therefore, by rotating the throttle plate, the throttle plate can be moved in the axial direction within the cylindrical pressure vessel.
The volume of the chamber in contact with the pressure gauge can be freely changed, and pressure can be measured while avoiding pulsation by setting an appropriate resonance frequency and time constant.

The present invention will be described below with reference to an embodiment shown in FIG.

A female thread is provided in the axial direction on the inner peripheral surface of the cylindrical pressure vessel 1 -2
A diaphragm plate 2o is provided which is screwed onto this and is equipped with a diaphragm such as a screw capillary to divide the inside of the pressure vessel 1 into two chambers AB and to vary the volume of each chamber. (In this embodiment, the top of the female screw of the diaphragm plate 2 is cut off.) Pressure is introduced from the pressure introduction hole 5 provided at one end of the pressure vessel 1, and passes through the diaphragm of the diaphragm plate 2.

Pressure is measured by a pressure gauge 7 attached to the other end of the pressure vessel 1.

The pressure introduction hole 5 is formed in a cap-shaped threaded portion 4, and its position can be changed by removing the threaded portion 4 and turning the nano) 2a attached to the aperture plate 2 with a spanner or the like.

Figure 3 shows a model diagram in which this device is replaced with an electric circuit.

Resistance (R) and inductance (L) of the electric circuit shown in the figure
, capacitance (0) [The formula for determining the corresponding Rr, Lα, and Cα is shown below.

r = A @EXP (-t/RtCα)le
= l + Q8f "u= l)h/S (f/amsCα= V/pCj"(am'Sec'/f
)R: /XEI''/2πS: Area of the aperture, l: Length of the aperture.

le: effective length, ρ: density, C: sound speed, ω; 2πff:
Frequency, ν. : Resonance frequency, Volume of two rooms B, τ: Time constant These values may be selected appropriately and the resonant frequency and time constant may be determined within a range that is acceptable for use.

Therefore, in the case of this embodiment, the pulsation absorption effect can be adjusted by moving the aperture plate 2 left and right to change the volume of the chamber B.

Furthermore, by removing the threaded portion 4, the aperture can be cleaned, and countermeasures against clogging and the like can be easily taken.

Also, if you make the volume of room B too large.

This is because the time constant becomes large and the response becomes slow.

The position of the aperture can be adjusted according to the pulsation frequency.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view of a conventional throttle device, FIG. 2 is a cross-sectional view of a throttle device showing an embodiment of the present invention, and FIG. 3 is an equivalent electrical circuit diagram. 1. Cylindrical pressure vessel, 2: Diaphragm plate, 2a: Nanoto, 7:
pressure gauge

Claims (1)

[Claims] A pulsation prevention device that is interposed between a pressure conduit that guides fluid pressure and a pressure gauge that measures the pressure of the fluid in the same pressure conduit. A pulsation prevention device comprising a cylindrical pressure vessel having a pressure gauge attached to its end, and a diaphragm plate having a diaphragm means that is screwed into a female thread of the pressure vessel and movable in the axial direction of the cylindrical pressure vessel.