JP3328006B2 - Impulse flow rate change generator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an impulse type flow rate change generator used for identifying acoustic characteristics of a piping system or a vessel in a plant or the like.

[0002]

2. Description of the Related Art In piping around a reciprocating compressor in a plant or the like, fluctuations in pressure and flow rate (hereinafter referred to as pipe pulsation) due to intermittent flow discharged or sucked from the reciprocating compressor.
Occurs. In particular, when air column resonance occurs or when the reciprocating compressor excites the air column, the pulsation in the pipe increases, causing pipe vibration, early damage to the compressor valve, and errors in flow measurement due to the orifice. May cause troubles in plant operation.

[0003] It is desirable to operate the plant while avoiding the resonance phenomenon of the air column. However, when the process conditions (sound speed) of the plant greatly change, it may be difficult to avoid it. Even if the air column is not in a resonance state, if the excitation force is large, pulsation in the pipe may be a problem. Therefore, it is important to perform pulsation analysis at the design stage to sufficiently grasp the pulsation phenomenon in the pipe and to design a pipe so as to minimize it.

However, pipes or vessels in a plant are difficult to analyze because boundary conditions are generally complicated, and a great deal of labor is required for simulation, and accurate analysis is not always performed. There is a problem that it is difficult.

[0005]

SUMMARY OF THE INVENTION In view of the above-mentioned problems of the prior art, a main object of the present invention is to directly identify the acoustic characteristics of an actual piping system or container and accurately determine the pulsation characteristics in the tubes. It is an object of the present invention to provide a device that allows the user to grasp the information.

[0006]

Means for Solving the Problems To achieve such an object
Therefore, in claim 1 of the present invention , there is provided an apparatus for generating an impulse-like flow rate change for identifying acoustic characteristics of an object composed of a piping system or a container, for storing a pressurized gas. A gas reservoir having a predetermined volume, a pressurized gas introducing means for introducing a pressurized gas of a predetermined pressure into the gas reservoir, and a pressurized gas in the gas reservoir being substantially impulse-shaped toward the identification target. impulsive to a valve means for releasing, characterized in that it has a means for obtaining on the basis of the flow rate history of gas released towards the to-be-identified from the gas reservoir to the measured values of pressure changes in the gas reservoir to the Flow rate change
We decided to provide a raw device.

According to a second aspect of the present invention, a piping system is provided.
Or to identify the acoustic characteristics of an object consisting of a container, etc.
An apparatus for generating an impulse-like flow rate change,
Gas reservoir having a predetermined volume for storing pressurized gas
And the pressure in the gas reservoir is sufficiently higher than the pressure in the identification target.
Pressurized gas introducing means for introducing a pressurized gas of pressure,
The pressurized gas in the gas reservoir is substantially
The opening area is determined so that it is emitted in a pulsed manner and at approximately the speed of sound.
Valve means consisting of a closed poppet valve and the gas reservoir
The flow history of the gas released into the object to be identified from the
Means for obtaining based on the measured value of the axial displacement of the pet valve
Generating an impulse-like flow rate change characterized by having
Equipment was provided.

[0008]

In this manner, the time history of the flow rate of the short-time high-speed gas flow, which is generally difficult to measure, can be obtained relatively accurately. It is possible to accurately identify the acoustic characteristics of the system or the container.

[0009]

FIG. 1 shows a first embodiment of the device according to the invention, in which a gas reservoir 1 having a predetermined volume and sealed is defined by a casing 2 and provided with a supply valve 4. From 3, compressed gas can be introduced into the gas reservoir 1. The casing 2 is provided with a gas discharge port 5 to be connected to a pipe or a container whose acoustic characteristics are to be identified, and a discharge valve 6 supported by a valve rod 7 at an inner end thereof.
A valve seat 5a for opening and closing the gas discharge port 5 is provided in coordination with the above. The discharge valve 6 and the valve seat 5a
A known poppet valve is constructed. The base end of the valve stem 7 projects toward the outside of the casing 2 via an O-ring 8, and the discharge valve 6 is always moved in the valve closing direction by a compression coil spring 9 mounted around the valve stem 7. Being energized. The valve rod 7 is provided with a valve-opening claw 10 to cooperate with the valve-opening lever 11. When the valve-opening lever 11 is at a predetermined position, the discharge valve 6 is closed as shown. Held in state.

The displacement sensor 12 detects the axial displacement of the valve rod 7.
Can be measured, the pressure sensor 13 can measure the pressure change in the gas reservoir 1.

According to this device, when the valve opening lever 11 is set to a predetermined position, the valve rod 7 is
The discharge valve 6 is kept closed by the spring force of (1). Next, the supply valve 4 is opened, and when the pressure in the gas reservoir 1 reaches a predetermined initial pressure, the supply valve 4 is closed.

When the valve opening lever 11 is rapidly turned in the direction of the arrow while the discharge port 5 is connected to a pipe or the like to be identified,
The valve-opening lever 11 overcomes the spring force of the compression coil spring 9 and lifts the valve-opening claw 10 in a short time.
Move away from 0. As a result, the valve stem 7 is lifted and the discharge valve 6 is opened. When the valve opening pawl 10 is separated from the valve opening lever 11, the valve rod 7 closes the discharge valve 6 rapidly by the spring force of the compression coil spring 9.

As a result, the pressure in the gas reservoir 1 decreases stepwise from the initial pressure to the pressure after opening as shown in FIG. 2, so that the pressure change rate obtained by differentiating the change amount is obtained. (FIG. 3) is pulsed. This signal has a direct correlation with the flow rate from the discharge port 5, and this signal is inverted as shown in FIG. Can be requested. That is, the time history of the pressure in the gas reservoir 1
If the time differential processing is performed by measuring the
Based on the equation of mass conservation (continuous) from the bulk modulus and density
To determine the flow history of gas released into the identification target.
Can be.

FIG. 5 shows a second embodiment of the present invention, in which parts corresponding to those of the above-described embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

In this embodiment, the discharge valve 6 is normally urged in the valve closing direction by the compression coil spring 9, and the cam follower 14 provided at the outer end of the valve rod 7 is By cooperating with the cam portion 17a of the slidably provided cam member 17 via the linear bearing 16, a short and controlled lift of the discharge valve 6 can be realized.

In this case, when the valve is opened, it is discharged from the discharge port 5.
The gas reservoir is set so that the flow rate of the emitted gas almost reaches the speed of sound.
The pressure of the gas stored in 1 is sufficiently high (above the critical pressure
To). As described above, the pressure in the gas reservoir 1 is measured.
If the pressure is maintained above the boundary pressure, the flow at the minimum opening of the valve
The speed of the body is constant at the critical sound speed, and the density is also
It is known to be constant. These values are in gas reservoir 1
And is not affected by the downstream side. Therefore, if the measurement result Xs (t) of the displacement sensor 12 that measures the axial displacement amount of the discharge valve 6 as shown in FIG.
The opening area of a poppet valve is proportional to the axial displacement of the valve.
From this relationship, we calculate using the relational expression of compressible fluid dynamics.
By doing so, the impulse flow rate of the gas discharged from the discharge port 5 can be obtained as shown in FIG. That is, the time history of valve displacement is measured.
The flow history of the released gas.
You.

[0017]

According to the present invention, the pressure change in the gas reservoir to be discharged to the piping system or the lift of the discharge valve can be reduced without having to directly determine the flow rate of gas in a short time and at a high speed. Since the flow rate of the released gas can be obtained through the above, an impulse input for identifying the acoustic characteristics of the piping system or the like can be accurately verified, and the acoustic characteristics of the piping system or the like can be accurately identified.

[Brief description of the drawings]

FIG. 1 is a diagram showing a first embodiment of the device according to the invention.

FIG. 2 is a graph showing a pressure change in a gas reservoir in the first embodiment.

FIG. 3 is a graph showing a pressure change rate obtained by differentiating a signal represented by the graph of FIG. 2;

4 is a graph showing an impulse flow rate obtained by performing a sign inversion and a coefficient multiplication process on the pressure change rate signal of FIG. 3;

FIG. 5 is a diagram showing a second embodiment of the present invention.

FIG. 6 is a graph showing a change over time of a lift amount of a discharge valve in a second embodiment.

7 is a graph showing an impulse flow rate obtained by performing a coefficient multiplication process on the lift amount signal of FIG. 6;

[Explanation of symbols]

 Reference Signs List 1 gas reservoir 2 casing 3 line 4 supply valve 5 discharge port 5a valve seat 6 discharge valve 7 valve rod 8 O-ring 9 compression coil spring 10 valve opening claw 11 valve opening lever 12 displacement sensor 13 pressure sensor 14 cam follower 15 fixed part 16 linear Bearing 17 Cam member 17a Cam

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G01F 15/06 G01L 11/04 G01M 7/02 G01M 19/00

Claims (2)

(57) [Claims] An apparatus for generating an impulse-like flow rate change for identifying acoustic characteristics of an object comprising a piping system or a container, the gas reservoir having a predetermined volume for storing a pressurized gas. Pressurized gas introduction means for introducing a pressurized gas of a predetermined pressure into the gas reservoir; valve means for discharging the pressurized gas in the gas reservoir toward the identification target in a substantially impulse shape; impulsive flow, characterized in that it comprises a means for obtaining <br/> based flow history of the emitted gas toward the gas reservoir to the identified object on the measurement values of the pressure changes in the gas reservoir
Quantity change generator . 2. The sound of an object consisting of a piping system or a container.
Generate impulse-like flow changes to identify characteristics
An apparatus for a gas reservoir having a predetermined volume for storing the pressurized gas
And a pressure sufficiently higher than the pressure in the identification target in the gas reservoir.
Pressurized gas introduction means for introducing a pressurized gas of
The opening area is determined so that it is emitted in a pulsed manner and at approximately the speed of sound.
Valve means comprising a closed poppet valve, and a flow rate of gas released from the gas reservoir into the object to be identified.
The history is based on the measured value of the axial displacement of the poppet valve.
Impulse-shaped means having
Flow change generator .