JPH05264386A - Differential pressure transmitter - Google Patents

Abstract

PURPOSE:To reduce the cost of the title transmitter and, at the same time, to improve the response characteristics and impact pressure resistance of the transmitter by using a porous material for its nest and transmitting pressures through the pores of the material. CONSTITUTION:Pressures applied to a first and second diaphragms 15 and 17 are respectively transmitted to a first and second sealing liquids 13' and 14' and further transmitted to a first and second sealing liquids 13 and 14 through the pores of a first and second nest plates 23 and 23 made of a porous material. The pressures are then transmitted to the pressure receiving surfaces of a differential sensor 10 through the liquids 13 and 14. The sensor 10 outputs an electric signal corresponding to the differential pressure between the pressures applied to its pressure receiving surfaces. When an excessively strong pressure is applied to either one of the diaphragms 15 and 17, the diaphragm 15 or 17 gets stuck to the nest plate 23 or 24 and, at the same time, a center diaphragm 7 is deformed. Therefore, the moving amount of the sealing liquid on the higher- pressure side is absorbed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a differential pressure transmitter and a differential pressure transmitter.

[0002]

2. Description of the Related Art FIG. 4 is a sectional view of a conventional differential pressure transmitter. In the figures, 1 is the first at one end
First concave portion 2 and second concave portion 3 formed at the other end
It is a pressure receiving body of. 4, a third concave portion that is opposed to the second concave portion of the first pressure receiving body 1 is formed at one end portion,
It is a second pressure receiving body having a fourth recess formed at the other end.

A center diaphragm 7 is sandwiched between the first pressure receiving body 1 and the second pressure receiving body 2. The first concave portion 2 and the second concave portion 3 of the first pressure receiving body 1.
And a second communication hole 9 is formed between the third recess 5 and the fourth recess 6 of the second pressure receiving body 4. ..

Reference numeral 10 is a differential pressure sensor. Reference numeral 11 denotes a first pressure guide hole that connects one pressure receiving surface of the differential pressure sensor 10 and the second recess 3 to each other, and 12 denotes a third pressure receiving surface of the sensor 10 and the other pressure receiving surface.
It is a second pressure guiding hole that communicates with the recess 5 of the.

Then, the first concave portion 2, the second concave portion 3, the first communicating hole 8 and the first pressure guiding hole 11 of the first pressure receiving body 1 are formed.
Is filled with the first filled liquid 13, and similarly, the third concave portion 5, the fourth concave portion 6, the second communicating hole 9 and the second pressure guiding hole 12 of the second pressure receiving body 4 are the second Is filled with the filling liquid 14.

A first diaphragm 15 is provided on the open surface of the first recess 2 of the first pressure receiving body 1, and the first diaphragm 15 is provided.
Between the diaphragm 15 and the bottom surface of the first recess 2,
A first nest 16 having the same shape as the corrugated shape of the first diaphragm 1 is formed. Similarly, on the open surface of the fourth recess 6 of the second pressure receiving body 4, the second diaphragm 1
7 is provided, and the second diaphragm 17 and the fourth recess 6 are provided.
A second nest 18 having the same shape as the corrugated shape of the second diaphragm 17 is formed between the second nest 18 and the bottom surface.

Next, the operation of the above configuration will be described. The pressure applied to the first diaphragm 15 and the second diaphragm is transmitted to each pressure receiving surface of the differential pressure sensor 10 via the first filled liquid 13 and the second filled liquid 14.

The differential pressure sensor 10 outputs an electric signal according to the differential pressure of the pressure applied to the pressure receiving surface. When an overpressure (for example, several hundred kg / cm ² ) acts on either the first diaphragm 15 or the second diaphragm 17, the first diaphragm 15 or the second diaphragm 17 Is seated on the first nest 16 or the second nest 18, and the center diaphragm 7 is deformed to absorb the movement amount of the enclosed liquid on the high pressure side.

[0009]

However, in the differential pressure transmitter having the above structure, the overpressure causes the first diaphragm 15,
Alternatively, when an overpressure acts on the second diaphragm 17,
These first diaphragm 15 and second diaphragm 1
The effect cannot be expected unless the shapes of No. 7 and the shapes of the first nest 16 and the second nest 18 are accurately matched. Therefore, the first nest 16 and the second nest 18 are
Waveform processing is performed using a high-precision cutting machine, which is a factor of cost increase.

Further, as shown in FIG. 5, when the diameters of the first and second communication holes 8 and 9 are large, the first and second diaphragms 15 and 17 are locally deformed when the diaphragm is seated. Impact pressure from a water hammer etc. is easily transmitted. For this reason, the communication hole must have the smallest possible diameter. However, since the cross-sectional area of the communication hole delays the response to the dynamic pressure fluctuation, it is necessary to form a plurality of communication holes as shown in FIG. 4, which also causes a cost increase.

Further, as shown in FIG. 6, the first and second diaphragms 15 and 17 have first and second nests 16 and 1, respectively.
There is a problem in that the first and second diaphragms 15 and 17 are seated on the sheet 8, and the first and second diaphragms 15 and 17 are partially contacted by the first and second communication holes 8 and 9, and a span failure at a low temperature is likely to occur.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a differential pressure transmitter capable of cost reduction and improvement of response characteristics and impact pressure resistance performance.

[0013]

The present invention for solving the above-mentioned problems comprises a diaphragm and a nest having the same shape as that of the diaphragm. When an excessive pressure acts on the diaphragm, the diaphragm sits on the nest. In a differential pressure transmitter having an overpressure prevention mechanism for preventing the transmission of excessive pressure, the nest is made of a porous material, and the pressure is transmitted through the holes of the porous material. It is a thing.

[0014]

In the differential pressure transmitter of the present invention, since the nest is made of the porous material, the pressure is transmitted through the porous hole. By using the porous material, the cost can be reduced, and the response characteristics and the impact pressure resistance performance can be improved.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a sectional configuration diagram of a first embodiment of the present invention, FIG. 2 is a diagram for explaining the operation, and FIG. 3 is a configuration diagram of a second embodiment of the present invention.

First, the first aspect of the present invention will be described with reference to FIGS. 1 and 2.
An example will be described. In these figures, the same parts as those in FIG. 4 which is a conventional example are designated by the same reference numerals, and the description thereof will be omitted.

In the figure, a first pressure receiving body 1 and a second pressure receiving body 1
Of the pressure receiving body 4 are formed with large recesses 21 and 22, and a porous first nest plate 23 and a second nest plate 24 are welded, brazed, diffusion-bonded, etc. to the large recesses 21 and 22. It is fixed by.

Further, in the space between the first nest plate 23 and the first diaphragm 15, the first enclosed liquid 13 'and in the space between the second nest plate 24 and the second diaphragm 17,
The second filled liquid 14 'is filled in each case.

Next, the operation of the above configuration will be described. The pressure applied to the first diaphragm 15 and the second diaphragm is transmitted to the first filled liquid 13 'and the second filled liquid 14'. Since the first and second nest plates 24 are made of a porous material, the pressure is transmitted to the first filled liquid 13 and the second filled liquid 14 through the holes formed in the nest plates 23 and 24, Furthermore, the first filled liquid 13 and the second filled liquid 1
It is transmitted to each pressure receiving surface of the differential pressure sensor 10 via 4.

The differential pressure sensor 10 outputs an electric signal according to the differential pressure of the pressure applied to the pressure receiving surface. When an overpressure (for example, several hundred kg / cm ² ) acts on either the first diaphragm 15 or the second diaphragm 17, the first diaphragm 15 or the second diaphragm 17 Is seated on the first nest plate 23 or the second nest plate 24, and the center diaphragm 7 is deformed to absorb the amount of movement of the enclosed liquid on the high pressure side.

According to the above construction, the porous nest plate 2
Since the diaphragms 3 and 24 are used, when the diaphragms 15 and 17 are seated on the nest plates 23 and 24 at the time of excessive pressure action, there is no communication hole as in the conventional case.
Local deformation does not occur. Further, since the diaphragms 15 and 17 do not evenly contact each other, a span failure is unlikely to occur at a low temperature.

Since the nest plates 23 and 24 are separate parts from the pressure receiving bodies 1 and 2, mold processing and the like can be performed, and the processing cost can be reduced. Next, a third embodiment of the present invention will be described with reference to FIG. In the figure, FIG.
The same parts as those of the above are given the same reference numerals, and the description thereof will be omitted.

In the figure, the first pressure receiving body 1 and the second pressure receiving body 1
The pressure receiving body 4 is provided with through holes 33 and 34, and the first nest plate 31 and the second nest plate 32 are fixed to the through holes 33 and 34, respectively.

In the space between the first nest plate 31 and the first diaphragm 15, the first enclosed liquid 13 'and in the space between the second nest plate 32 and the second diaphragm 17, the second fill liquid 13' is formed.
Are filled with each of the filling liquids 14 '. Further, the first enclosed liquid 13 ″ is in the space between the first nest plate 31 and the center diaphragm 7, and the second enclosed liquid 14 ″ is in the space between the second nest plate 32 and the center diaphragm 7. , Each filled.

According to the above construction, the same effect as that of the first embodiment can be obtained.

[0026]

As described above, according to the present invention, it is possible to realize a differential pressure transmitter capable of reducing the cost and improving the response characteristics and the impact pressure resistance performance.

[Brief description of drawings]

FIG. 1 is a sectional configuration diagram of a first embodiment of the present invention.

FIG. 2 is a diagram illustrating an operation.

FIG. 3 is a configuration diagram of a second embodiment of the present invention.

FIG. 4 is a cross-sectional configuration diagram of a conventional differential pressure transmitter.

FIG. 5 is a diagram illustrating a problem.

FIG. 6 is a diagram illustrating a problem.

[Explanation of symbols]

 1, 4 Pressure receiving body 10 Center diaphragm 15,17 Diaphragm 23,24 Nest plate

Claims (1)

[Claims] 1. An overpressure which comprises a diaphragm and a nest having the same shape as the diaphragm, and when an excessive pressure acts on the diaphragm, the diaphragm is seated on the nest to prevent the transmission of the excessive pressure. A differential pressure transmitter having a prevention mechanism, wherein the nest is made of a porous material, and pressure is transmitted through a hole of the porous material.