JPH0875584A - Differential pressure measuring instrument - Google Patents

Abstract

PURPOSE: To reduce the cost of a device and to improve reliability by using a built-in uniform-pressure mechanism consisting of a uniform-pressure path, a connecting hole, a gate valve, and a stop valve for performing zero-point check. CONSTITUTION: A high-pressure side uniform-pressure path 31 where one terminal is opens at a high-pressure-side pressure introduction room 11 and a low- pressure side uniform-pressure path 32 which opens at a low-pressure side pressure introduction room 10 are provided. Also, the other terminal of the path 32 and that of the path 31 are connected and a gate valve 35 for opening and closing the connection hole 33 is provided. Further, a high-pressure side pressure- guiding pipe 36 with a high-pressure side stop valve 38 halfway and a low- pressure side pressure-guiding pipe 37 with a low-pressure side stop valve 39 are connected to introduction ports 5 and 4. Then, first the gate valve 35 is loosened to cause the path 31 and the path 32 to continue. Then, pressure applied to seal diagrams 12 and 13 is made uniform after closing both stop valves 39 and 38 and then zero-point check is made, thus reducing the cost of a device and at the same time improving the reliability in instrumentation by reducing the number of points where a measurement liquid leaks.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a differential pressure measuring device capable of reducing cost and improving reliability of instrumentation.

[0002]

2. Description of the Related Art FIG. 2 is an explanatory view of the configuration of a conventional example which has been generally used, for example, Japanese Patent Laid-Open No. 59-56137.
It is shown in FIG. In the figure, the housing 1
Flanges 2 and 3 are fitted and assembled on both sides of and are fixed by welding or the like. Both flanges 2 and 3 are provided with a high-pressure fluid inlet 5 of pressure P _H to be measured and pressure P _L.
The low-pressure fluid inlet 4 is provided.

A pressure measuring chamber 6 is formed in the housing 1, and a center diaphragm 7 and a silicon diaphragm 8 are provided in the pressure measuring chamber 6. The silicon diaphragm 8 has a recess 82 in a single crystal silicon substrate 81.
Is formed.

The center diaphragm 7 and the silicon diaphragm 8 are separately fixed to the wall of the pressure measuring chamber 6, and the center diaphragm 7 and the silicon diaphragm 8 are separately fixed.
The pressure measuring chamber 6 is divided into two parts by both. Back plates 6A and 6B are formed on the wall of the pressure measuring chamber 6 facing the center diaphragm 7. The center diaphragm 7 has a peripheral edge portion welded to the housing 1.

Impurities such as boron are selectively diffused on one surface of the silicon substrate 81 to form four strain gauges 91. The four strain gages 91 are pulled when the silicon diaphragm 8 bends under the pressure difference ΔP,
Two are to be compressed and these are
Connected to Toston bridge circuit, resistance change is differential pressure Δ
It is detected as a change in P.

Reference numeral 92 is a lead whose one end is attached to the strain gauge 91. 93 is a hermetic terminal to which the other end of the lead 92 is connected. A temperature sensor 94 is provided near the strain gauge 91 (not shown). The support 9 is provided with a hermetic terminal, and the silicon diaphragm 8 is adhesively fixed to the end surface of the support 9 on the pressure measurement chamber 6 side by a method such as low-melting glass connection.

Pressure introducing chambers 10 and 11 are formed between the housing 1 and the flange 2 and the flange 3. First and second seal diaphragms 13 and 12 are provided in the pressure introducing chambers 10 and 11, and walls 10A and 11A of the housing 1 facing the seal diaphragms 12 and 13 are provided.
A back plate having a shape similar to that of the seal diaphragms 12 and 13 is formed on the.

The space formed by the seal diaphragms 12 and 13 and the back plates 10A and 11A and the pressure measuring chamber 6 are in communication with each other through communication holes 14 and 15. Filling liquids 101 and 102 such as silicon oil are filled between the seal diaphragms 12 and 13, and the filling liquids reach the upper and lower surfaces of the silicon diaphragm 8 through the communication holes 16 and 17. It is divided into two by the center diaphragm 7 and the silicon diaphragm 8, and it is taken into consideration that the amounts are almost equal.

In the above structure, when pressure is applied from the high pressure side, the pressure acting on the seal diaphragm 13 is transmitted to the silicon diaphragm 8 by the enclosed liquid 102. On the other hand, when pressure acts from the low pressure side, the pressure acting on the seal diaphragm 12 is transmitted to the silicon diaphragm 8 by the enclosed liquid 101.

As a result, the silicon diaphragm 8 is distorted according to the pressure difference between the high pressure side and the low pressure side, and the strain amount is electrically taken out by the strain gauge 91, and the differential pressure is measured. .

[0011]

However, in such an apparatus, since the pressure difference between the high pressure side pressure and the low pressure side pressure of the measurement pressure is measured, the zero point check is always necessary. Normally, in order to check the zero point,
As shown in FIG. 3, a stop valve 21 is provided in the high pressure side pipe and the low pressure side pipe, and a pressure equalizing valve 22 is provided therebetween, or as shown in FIG. 4, a three-way valve 23 in which these are integrated is connected and operated. I am checking the zero point.

However, the stop valve 21 and the pressure equalizing valve 22 or the three-way valve 23 increase the instrumentation cost. In addition, leakage of the measurement fluid easily occurs from the joint portion of the stop valve 21, the pressure equalizing valve 22 and the three-way valve 23, and if the measurement fluid is corrosive, flammable, or toxic fluid, it may lead to a major accident.

The present invention solves this problem. An object of the present invention is to provide a differential pressure measuring device which can reduce the cost and improve the reliability of instrumentation.

[0014]

In order to achieve this object, the present invention provides a differential pressure measuring device in which a high pressure side pressure introducing chamber and a low pressure side pressure introducing chamber are provided on both side surfaces of a main body housing, respectively. A high pressure side pressure equalizing passage which is provided in the main body housing and has one end opening to the high pressure side pressure introducing chamber; a low pressure side equalizing passage which is provided in the main body housing and whose one end opens to the low pressure side pressure introducing chamber; A communication hole, which is provided in the housing, communicates the other end of the low-pressure side equalizing passage and the other end of the high-pressure side equalizing passage, and one end of which constitutes a valve seat, and the main body housing which opens and closes the valve seat. A gate valve, a high-pressure side pressure guiding pipe whose one end is connected to the high-pressure side pressure introducing chamber, a low-pressure side pressure guiding pipe whose one end is connected to the low-pressure side pressure introducing chamber, and a high-pressure side pressure guiding pipe provided in the middle thereof. High pressure stop valve, It is obtained by constituting the differential pressure measuring device, characterized in that serial equipped with a low pressure side impulse line of the low pressure side stop valve provided in the middle.

[0015]

In the above construction, when pressure is applied from the high pressure side, the pressure acting on the seal diaphragm is transmitted to the silicon diaphragm by the enclosed liquid. On the other hand, when pressure acts from the low pressure side, the pressure acting on the seal diaphragm is transmitted to the silicon diaphragm by the enclosed liquid.

Therefore, the silicon diaphragm is distorted according to the pressure difference between the high pressure side and the low pressure side, and the strain amount is electrically taken out by the strain gauge, and the differential pressure is measured.

Next, at the time of zero point check. To check the zero point of the differential pressure measuring device, apply the same pressure to the seal diaphragm. Normally, the sluice valve is closed, and the high-pressure side equalizing passage and the low-pressure side equalizing passage are not in conduction.

First, the sluice valve is loosened so that the high-pressure side equalizing passage and the low-pressure side equalizing passage are brought into conduction. Next, close the low-pressure stop valve to achieve a pressure equalization state for the seal diaphragm, or close the low-pressure stop valve and high-pressure side stop valve to achieve a pressure equalization state for the seal diaphragm. To do. After that, a zero point check is performed. Hereinafter, detailed description will be given based on an embodiment.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an explanatory view of the essential structure of an embodiment of the present invention. In the figure, the same symbols as those in FIG. 2 represent the same functions. Only parts different from FIG. 2 will be described below.

Reference numeral 31 is a high pressure side pressure equalizing passage which is provided in the main body housing 1 and has one end opened to the high pressure side pressure introducing chamber 11. Reference numeral 32 denotes a low pressure side pressure equalizing passage which is provided in the main body housing 1 and has one end opening to the low pressure side pressure introducing chamber 10.

Reference numeral 33 is a communication hole which is provided in the main body housing 1 and which communicates the other end of the low pressure side pressure equalizing passage 32 and the other end of the high pressure side equalizing passage 31 with one end constituting a valve seat 34. Three
Reference numeral 5 is a sluice valve that is provided in the main body housing 1 and that opens and closes the valve seat 34.

Reference numeral 36 is a high pressure side pressure guiding tube having one end connected to the high pressure side pressure introducing chamber 11. Reference numeral 37 is a low pressure side pressure guiding tube having one end connected to the low pressure side pressure introducing chamber 10. 38
Is a high-pressure side stop valve provided in the middle of the high-pressure side pressure guiding pipe 36. Reference numeral 39 is a low pressure side stop valve provided in the middle of the low pressure side pressure guiding pipe 37.

In the above structure, when pressure is applied from the high pressure side, the pressure acting on the seal diaphragm 13 is transmitted to the silicon diaphragm 8 by the enclosed liquid 102.

On the other hand, when the pressure acts from the low pressure side, the pressure acting on the seal diaphragm 12 is transmitted to the silicon diaphragm 8 by the enclosed liquid 101. Therefore,
The silicon diaphragm 8 is distorted according to the pressure difference between the high pressure side and the low pressure side, and the strain amount is electrically taken out by the strain gauge 91, and the differential pressure is measured.

Next, at the time of zero point check. In order to check the zero point of the differential pressure measuring device, the pressure applied to the seal diaphragms 12 and 13 is made the same. Normally, the sluice valve 35 is closed, and the high pressure side pressure equalizing passage 31 and the low pressure side pressure equalizing passage 32 are not in a conductive state.

First, the sluice valve 35 is loosened so that the high pressure side pressure equalizing passage 31 and the low pressure side pressure equalizing passage 32 are brought into conduction. Next, the low-pressure stop valve 38 is closed, and the seal diaphragm 1
The pressure applied to the pressure diaphragms 2 and 13 is equalized, or the low-pressure stop valve 39 and the high-pressure stop valve 38 are closed to equalize the pressure applied to the seal diaphragms 12 and 13. After that, a zero point check is performed.

As a result, according to the present invention, since the pressure equalizing mechanism is built in the transmitter, it is not necessary to attach a three-way valve or the like to the pipe, and therefore the cost of the three-way valve or the like can be reduced.
In addition, the number of piping connections can be reduced to reduce the number of points where the measured solution leaks, leading to improved instrumentation reliability.

[0028]

As described above, the present invention is provided in the main body housing in the differential pressure measuring device in which the high pressure side pressure introducing chamber and the low pressure side pressure introducing chamber are provided on both side surfaces of the main body housing. A high pressure side pressure equalizing passage having one end opening to the high pressure side pressure introducing chamber; a low pressure side pressure equalizing passage having one end opening to the low pressure side pressure introducing chamber; A communication hole that communicates the other end of the side pressure equalizing passage with the other end of the high pressure side pressure equalizing passage, one end of which forms a valve seat; a sluice valve that is provided in the main body housing to open and close the valve seat; A high pressure side pressure guiding pipe whose one end is connected to the side pressure introducing chamber, a low pressure side pressure guiding pipe whose one end is connected to the low pressure side pressure introducing chamber, and a high pressure side stop valve provided in the middle of the high pressure side pressure guiding pipe. , The way of the low-pressure side impulse pipe It was equipped with a low pressure side stop valve provided to constitute a differential pressure measuring device, characterized in the.

As a result, according to the present invention, since the pressure equalizing mechanism is built in the transmitter, it is not necessary to attach a three-way valve or the like to the pipe, and therefore the cost of the three-way valve or the like can be reduced.
In addition, the number of piping connections can be reduced to reduce the number of points where the measured solution leaks, leading to improved instrumentation reliability.

Therefore, according to the present invention, it is possible to realize the differential pressure measuring device which can reduce the cost and improve the reliability of the instrumentation.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a main part configuration of an embodiment of the present invention.

FIG. 2 is an explanatory diagram of a configuration of a conventional example that is generally used in the past.

FIG. 3 is a detailed explanatory diagram of a main part of FIG.

FIG. 4 is a detailed explanatory diagram of a main part of FIG.

[Explanation of symbols]

 1 ... Housing 2 ... Flange 3 ... Flange 4 ... Inlet port 5 ... Inlet port 6 ... Pressure measuring chamber 6A ... Back plate 6B ... Back plate 7 ... Center diaphragm 8 ... Silicon diaphragm 9 ... Support 10 ... Pressure introduction Chamber 10A ... Back plate 11 ... Pressure introducing chamber 11A ... Back plate 12 ... Seal diaphragm 13 ... Seal diaphragm 14 ... Communication hole 15 ... Communication hole 16 ... Communication hole 17 ... Communication hole 21 ... Stop valve 22 ... Pressure equalizing valve 23 ... Three-way valve 31 ... High pressure side pressure equalizing passage 32 ... Low pressure side pressure equalizing passage 33 ... Communication hole 34 ... Valve seat 35 ... Partition valve 36 ... High pressure side pressure guiding pipe 37 ... Low pressure side pressure guiding pipe 38 ... High pressure side stop valve 39 ... Low-pressure stop valve 81 ... Silicon substrate 82 ... Recessed portion 91 ... Strain gauge 92 ... Lead 93 ... Hermetic terminal 101 ... Filled liquid 10 ... sealed liquid

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Atsuko Kanehira 2-9-32 Nakamachi, Musashino City, Tokyo Yokogawa Electric Co., Ltd.

Claims (1)

[Claims] 1. A differential pressure measuring device in which a high-pressure side pressure introducing chamber and a low-pressure side pressure introducing chamber are provided on both sides of a main body housing, wherein one end of the main body housing is opened to the high pressure side pressure introducing chamber. A high-pressure side equalizing passage, a low-pressure side equalizing passage that is provided in the main body housing and has one end opening to the low-pressure side pressure introducing chamber, and another end of the low-pressure side equalizing passage that is provided in the main body housing and the high pressure. A communication hole that communicates with the other end of the side pressure-equalizing passage and one end of which forms a valve seat, a sluice valve that is provided in the main body housing to open and close the valve seat, and one end of which is connected to the high-pressure side pressure introduction chamber A high-pressure side pressure guiding pipe, a low-pressure side pressure guiding pipe whose one end is connected to the low-pressure side pressure introducing chamber, a high-pressure side stop valve provided in the middle of the high-pressure side pressure guiding pipe, and a middle of the low-pressure side pressure guiding pipe. Low pressure side Differential pressure measuring device, characterized by comprising a valve.