JPS59195132A - Shock tube - Google Patents

Abstract

PURPOSE:To determine precisely and directly the response characteristic of a transmitter by adhering the openings of two pressure cases having different openings respectively through a thin film and providing the pressure case having a large opening with a pressure guiding port and the other pressure case with a pressure detecting means and a pressure guide interrupting means. CONSTITUTION:The pressure case 11 having a large opening 13 and the case 16 having a small opening 17 are adhered and fixed through the thin film 15 and an O-ring 14 by fitting a male screw 19 to a female screw 20. The capacity of the inside 18 of the pressure case 16 is set up to a sufficiently small value as compared to the inside 21 of the pressure case 11. High pressure fluid is guided to a guiding port of the inside 21 of case 11, and when the pressure becomes a sufficiently high level, the thin film 15 is instantaneously damaged, a shock pulse is generated in the inside 21 of the case 11 and supplied to a pressure transmitter fromed on the inside 18. When the pressure of the inside 18 of the case 16 reaches atmospheric pressure, inflow of the high pressure fluid is interrupted. Thus, the response characteristic of the transmitter can be determined precisely and directly.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a shock amplifier that realizes a fluid pressure whose pressure changes rapidly, and the object thereof is to make the fluctuation of the fluid pressure step-like. An object of the present invention is to provide a shock tube having the following characteristics.

In chemical plants and the like, various types of fluids including gas are supplied to various reaction tanks using vibrators. At the factory,
So-called pressure transmitters are widely used, which use the pressure inside the vibrator of the fluid to transmit electrical signals to a control room installed at a remote location. The pressure transmitter is manufactured using a well-known technology, and can be selected from a series of similar products depending on the magnitude of the fluid pressure to be measured. The characteristics of such a transmitter include linearity, temperature characteristics, frequency response characteristics, etc. in addition to the fluid pressure range to be measured.

The frequency response characteristic described last indicates how accurately 7Jx transmits an electrical signal in response to time changes in the fluid pressure to be measured. It was not written as a highly reliable characteristic value. - To give an example:

In some cases, it has been proposed as a theoretical value based on bending. In other words, even in transmitters manufactured according to the same standard,
The labeling was uniform and simple, without taking into consideration the variations in the characteristics of individual products. As a result of examining this current situation, it was found that there is a problem with the evaluation method of frequency response characteristics. In other words, in the conventional measurement method, a shock tube that generates fluid pressure in an impulse manner is used as a signal source. The analysis became complicated and unrealistic.

In the field of electronic engineering, 'impulse electrical signals are used to understand the frequency response characteristics of electrical circuit networks.

It is theoretically possible to analyze the output value using methods such as Fourier transform. However, if an ideal impulse signal cannot be generated, it becomes difficult to correct errors. Due to such usage, in the electric circuit network, a staircase wave signal is used instead of the impulse electric signal. Although it is difficult to ideally realize a staircase wave signal, generally speaking, it is known that it is relatively easier to generate than the above-mentioned impulse signal. The present invention was made in consideration of a method for measuring frequency response characteristics in the field of electronic engineering. That is, the present invention provides a shock cheese, which is a fluid pressure generating device having a step-like temporal change, which allows the response characteristics of the above-mentioned one transmitter to be determined more accurately and directly.

When using the shock tube according to the present invention, the frequency response of the pressure sensor such as the above-mentioned transmitter, for example, a pressure sensor using silicon, a shock sensor, an ultrasonic sensor, etc. −1～
−−−−−−−−−−−−'−Answer characteristics can be easily measured. The present invention provides a first pressure vessel, a means for introducing fluid into the pressure vessel at a pressure higher than atmospheric pressure, and an opening provided in a part of the pressure vessel. a second pressure vessel having a membrane made of metal or other material, a second pressure vessel having openings formed in parallel with the four membranes, and detecting the pressure within the second pressure vessel. A shock chest is provided comprising means and means for preventing said fluid from entering said first pressure vessel.

Next, the present invention will be described in detail with reference to the drawings.

FIG. 1 is a diagram explaining a conventional shock cheese.
A cross-sectional view is shown. In the figure, reference numeral 1 denotes a cylindrical pressure vessel with high mechanical strength made of gold stripes, etc., and has a fluid inlet 2 at one end for introducing fluid at a pressure higher than atmospheric pressure, and an open hole at the other end. 3 is provided. 4 is an O-ring for airtight sealing, 5 is a thin film made of metal or other materials, and 6 is a front cover having an opening 7' in the center. Since this is a diagram showing the conceptual concept of @, l, 4.4, 5.5, and 6 are shown separated from each other, but in reality, the mutual relationship between 4 and 5 is maintained, 6 and 1 are tightly attached to each other in a sandwiching manner. Such a strong connection is achieved by, for example, a male thread provided on the outer periphery of 1 and a female thread provided on 6 (both not shown). This is achieved by 1).
and 6 constitute a pressure vessel. Of course, the necessary conditions are that the inner diameter of 4 is larger than the diameter of 3, that 5 is larger than the outer diameter of 4, and that the diameter of 7 is smaller than the inner diameter of 4. The internal space of the chamber 1, which is almost hermetically sealed by the O-ring 4, has an increased pressure due to the fluid flowing through the chamber 2. This pressure increase acts to force the membrane of 5 onto 6 and forces a portion of 5 into the interior of the aperture 7. , 5 is induced inside 5, 5 instantly breaks, and the high pressure fluid inside 1 flows out of the pressure vessel via 7. In the spatial region 8 on the left side of 7, an impulse-like fluid shock pulse is generated due to the damage. Here, if the transmission path is defined in 8 parts, the pulses will be supplied. However, in such a conventional example, the peak value of the shock pulse in the form of < 7 is not uniquely defined, but is highly dependent on the fixed position and direction of the transmitter, and is difficult to measure. Variations occur in the values. It is still difficult to theoretically obtain the peak value.

FIG. 2 is a diagram showing one embodiment of the present invention, and a cross-sectional view is shown. In the figure, 11 is a cylindrical first pressure vessel made of metal or the like, and 12 is an inlet for introducing fluid into the pressure vessel at a pressure higher than atmospheric pressure, such as an air compressor L. Cheeve from Sa is connected. Reference numeral 13 is a hole provided at one end of the pressure vessel, 14 is an O-ring, and 15 is a thin film made of metal or other material such as rubber. 16 is a second pressure vessel having an opening 17 provided in close contact with 15; In the same figure, for convenience of explanation, the respective formation elements are shown separated from each other. ,
14 and 15 are placed in close contact with each other to form one pressure vessel. In such a configuration, 1
The necessary conditions are that the diameter of 3 is smaller than the inner diameter of 14, that 15 is larger than the outer diameter of 14, and that the diameter of 17 is /J% smaller than the inner diameter of 14. Of course, the shape of 13.degree. 17 is limited to a circle, but may also be a quadrilateral or a polygon, but conditions similar to the above requirements are required. When a fluid with a pressure higher than atmospheric pressure is sent into the interior 21 of 11, the O-ring 14 prevents the fluid from flowing out to the outside space, and pushes the right side of 15 to the left. generate force. That is, 15 is pressed into the opening 17 of 16, and a portion is pushed into the inside of 17.

When the pressure of 21 becomes high enough and the stress induced inside 15 exceeds the breaking strength determined by the particles of 15, 15 will instantly break and the high-pressure fluid accumulated inside 21 will collapse into 16. into the interior 18 of. The inflow is 18 and 2
The connection is made until the time when the pressures of 18 and 21 become equal, and after that time, 18 and 21 are held equal. The time required to reach this point is determined by the conductance of the fluid when it passes through the aperture 17, but the time required for energization is so small that it can be ignored. For this reason, if the pressure of 18 is detected and the inflow of fluid from 12 is blocked at the time when the desired pressure above atmospheric pressure is reached, 18.2
The pressure within 1 is maintained at a constant value. Due to this operation, 1
8, a stepped fluid shock pulse is generated. Here, if the transmitter is fixed to section 18, the pulses will be supplied. That is, a measurement method similar to the staircase wave input method in the electronic circuit described above can be easily realized.

In the embodiment shown in FIG. 2, when 15 is damaged and the high-pressure fluid 21 flows into 18, the fluid expands, so the fluid pressure value immediately before 15 is broken is not maintained, and it is slightly pressure drop occurs.

FIGS. 3(a), 3(b), and 3(c) are diagrams conceptually showing the pressure changes of 18. The horizontal axis in the figure is the time axis, t.

It is assumed that 15 is damaged in the process. Moreover, the vertical axis shows the pressure of 18, and Po is the pressure of 21 immediately before 15 breaks. FIG. 4(a) shows an ideal wave-like shock pulse of more than one step. However, as described above, due to the expansion of the fluid and due to the damping effect of the movement of the fluid at 21.18, an una shock pulse as shown in FIG. 3(b) is actually written. To solve this problem, if the ratio of the volume of 21 to the volume of 18 is set to 1:99, the size of the overshoot in FIG.
This does not pose a problem when determining the frequency response characteristics of a normal transmitter. However, increasing the volume of 21 is
The airtight leakage existing between 15 and 16 and between 19 and 20 is also preferable since it has the effect of substantially reducing the drop in pressure value after to.

According to the aforementioned operating principle, 15 is partially pushed into the opening of 17 previously. C1] If the shape of 17 is circular, then 15. It is clear that the diaphragm acts as a circular diaphragm with a diameter equal to the diameter d of 17. It is known that the fluid pressure of the circular tie 7 slam, that is, the stress generated against a uniformly distributed load is proportional to (d/l).

However, t is the diaphragm thickness. On the other hand, since the breaking strength of the diaphragm depends on the material, the pressure 21 required to break the diaphragm can be arbitrarily set by selecting d or t. That is, in FIG.
By preparing the pressure vessel 16, it is possible to obtain a shock pulse having the height of the MfJ step wave as required. FIG. 3(C) shows the waveform of a shock pulse of Pl with a larger aperture diameter of -17 and a lower height, that is, smaller than Po. The fourth @ shows an example of how to make d more convenient. In this figure, the same numbers as in FIG. 3 indicate the same bridge components.

This embodiment is characterized in that a pressure booster 40 is disposed inside the pressure booster 16. In other words, a plurality of boosters 40 are prepared in advance, which are detachable from -, 16-, and have holes 41 provided near the center with varying diameters or hole shapes. Select the particular booster 40 to obtain the pulse and attach it to 16. In such a case, it becomes possible to measure any pulse without removing the transmitter which is fixed inside the 16-piece.

Immediately after the thin film 15 is broken, a part of the broken part 15 is broken into 18 inside 16 due to the fluid flowing from 21 to 16.
be drawn into. In experiments conducted by the inventor, the broken fragments were not drawn into 18. That is, the breakage was caused only by the thin film, but the shape of the breakage was not self-evident. However, if the pressure-sensitive part of the transmitter fixed to 18 is not protected by security G), then after said breakage, the part of 15 drawn into 18,
There is a risk of damage to the pressure sensitive parts. FIG. 5 shows an embodiment aimed at preventing damage to the transmitter.

In Figure II, the same numbers and components as in Figure 2 are shown, and 50 is the transmitter. The shape of the opening 17 is circular, the diameter inside the nucleus is d, and the distance from the contact surface of 15 to the tip of 50 is indicated by D. Here, if D is set larger than d, even if 15 is damaged, a part of 15 (indicated by 51) drawn into 18 will contact the tip of 50. The transmitter 50 will not be damaged and is safe.

Next, another embodiment of the present invention is shown in FIG. 6VC. In Figure 1, the structure shown in Figure 2 is simplified and schematically shown. Note that the same numbers as in FIG. 2 indicate the same components. In the same figure, at I7), 60 degrees 61 are piping such as urethane tubes each having connection means (not shown) to 21 and 18.

62 is an air-operated valve, the pilot pressure is supplied with the fluid pressure in 18 through 61, the pressure above atmospheric pressure is supplied to the input port 63 through the terminal 65, and the υ1 air boat 64 The output from 66 is passed through the 21-door loop 66 and is supplied to 21 via 60. 67 is a manual valve, the input port is commonly connected to 60, and the output boat is open to the atmosphere. Further, 568 is a lever. The operation in this embodiment will be described below. Since the lever 68 is set in the direction shown, the first pressure vessel 11 is
7f: Not exposed to the atmosphere via.

Immediately after sealing between surface 15-f:ll and 16,
Since the pressure 18 is the same as the atmospheric pressure, the air operating valve 62 is in a state where the input port 3 and the exhaust port 64 are connected. In this state r (when fluid pressure is applied from 65, 2
1 pressure increases. However, such a rise in haka will be achieved gradually through 11 Dorno rubs 66. , 21 exceeds the breaking strength of 15, as mentioned above. [The corruption of time occurs. As a result of such rupture, the pressure within the second pressure vessel 16 increases instantaneously from atmospheric pressure to that pressure, activating the air operated valve 62. That is, the pilot pressure introduction boats 61 and 62 and 62 serve as means for detecting the pressure within the second pressure vessel 16. The actuation of 62 changes the connection between input port 3 and exhaust port 64, and prevents fluid flow between 63 and 64. This action prevents the fluid being supplied to 65 from reaching the first pressure vessel '11, so that the pressure in 21 no longer increases but remains constant. The constant pressure 10 can be changed to 1 by switching the lever 68.
8.21 is connected to the atmosphere through 67.

In addition, in the opening yi pocket, the pilot pressure of 62 becomes equal to the atmospheric pressure again, so the fluid from 65 tries to flow into 21, but because of 67, it always flows into the atmosphere;・1
Since it is released, there is no increase in the pressure of 21. It is easy for a person skilled in the art to realize that this phenomenon can be prevented by stopping the fluid supply to 65, and is not related to the essence of the present invention. Avoid details. FIGS. 7(a) and 7(b) are diagrams showing a pressure change of 21°18 when such an operation is followed.

The same figure (a) shows the pressure change of 21, the same figure (b) shows the pressure change of 18, to is the time of failure of 15, and Po is 1.
This is the pressure value of 21 immediately before failure of 5. In this embodiment, even if 15 is damaged, the pumping of fluid into 21 will continue unless 62 is activated. ) may be slightly larger than Po. However, as shown in FIG. 7(a), if we note that the pressure change inside 21 due to the fluid pressure is gradual, the error due to the response time of the constant pressure value is Can be ignored in practical terms. In addition, in this embodiment, by narrowing down the needle valve 66, that is, reducing the amount of fluid passing through,
It is clear that the error difference can be set even smaller. Further, in this embodiment, the means for detecting the pressure in the second pressure vessel and the means for preventing fluid from flowing into the first pressure vessel by the means are realized by 62 air-operated valves. Although the case is shown, the detecting means is an air pilot actuator or the like that is operated by the pressure of 18,
A mechanically operated valve operated by the F-Pilot actuator may be used as the blocking means.

The present invention has been described in detail above. According to the present invention, instead of the conventional impulse-like change in fluid pressure over time, a shock coefficient that provides a step-like change in fluid pressure over time is achieved.
With this method, evaluation of various pressure detection elements including the pressure transmitter described above can be performed in one step.

[Brief explanation of drawings]

FIG. 1 is a diagram illustrating a conventional shock cheese. 2 to 7 are diagrams for explaining each embodiment of the present invention. In the figure, 1.11.16...Pressure vessel, 2,12...Fluid inlet, 3,13,17.41...Opening hole, 4.14...
・O-ring, 5, 15...Thin film, 6...Front lid, 1
9゜20...screw, 40...pressure booster, 50
... Pressure 1 transmitter, 51 ... Part of damaged 15,
60.61...Piping, 62...Air operated valve, 66.
...21 dollar valve, 67...manual valve, 68...lever, teal. No. 1 B No. 2 No. n No. 3 (a) (b) (C) No. IJ-1 No. 5

Claims (1)

[Claims] a first pressure vessel, a means for introducing fluid into the pressure vessel at a pressure greater than atmospheric pressure, and a metal or other material provided in close contact with an aperture provided in a portion of the pressure vessel; a second pressure vessel having an aperture formed in close contact with the thin membrane, and a means for detecting pressure in the second pressure vessel; No.l
A shock tube characterized in that it has a means for preventing the introduction of the shock tube into a pressure vessel.