JPH02269932A - Differential pressure measuring instrument - Google Patents

Abstract

PURPOSE:To reduce the size, weight, and cost of the measuring instrument and to obtain the device which has small static pressure span variation by varying differentially the electrostatic capacities between fixed electrodes and a measuring diaphragm by the displacement of the measuring diaphragm. CONSTITUTION:An internal chamber 12 is divided into two measurement chambers 14 and 15 and the measuring diaphragm 13 which functions as a moving electrode is provided. Insulating films 131 and 132 are formed on the internal surface of the internal chamber 12 by the plasma melt spraying of ceramic, and the fixed electrodes 133 and 134 are provided on the surfaces of the insulating films 131 and 132 opposite the diaphragm 13. Further, two connecting holes 43 and 44 which are connected to a pressure receiving chamber 41 provided to a base block 4, at one-end sides and open to the outside at other-end sides as pressure receiving connecting ports are provided. Then the connecting holes 43 and 44 are linked with each other, so measurement pressure is applied to a main body 11 from right and left, and the diaphragm 13 is displaced by the differential pressure of the measurement pressure. The electrostatic capacity between the fixed electrodes 133 and 134 and diaphragm 13 vary differentially by the displacement of the diaphragm 13 and an electric signal corresponding to the differential pressure is obtained.

Description

[Detailed description of the invention] <Industrial application field> The present invention relates to a differential pressure measuring device.

More specifically, the present invention relates to an input circuit of a differential pressure measuring device.

<Prior Art> FIG. 6 is a diagram illustrating the configuration of a conventional example of a flow rate measurement system using an orifice that has been commonly used.

In the figure, A is a conduit through which the measurement fluid flows.

B is an orifice provided in conduit A.

C is a conduit attached to conduit A upstream or downstream of orifice B. C1 is a main valve that opens and closes the conduit.

D is a three-way valve connected to conduit C. Dl is a stop valve provided on the three-way valve, and D2 is a pressure equalization valve.

E is a differential pressure measuring device connected to a three-way valve.

<Problems to be Solved by the Invention> However, in such a device, the three-way valve and the differential pressure measuring device E are separate bodies, and mutual piping is required. Further, the device becomes complicated, and it is difficult to reduce the size and weight of the device and reduce the cost.

The present invention solves this problem.

An object of the present invention is to provide a differential pressure measuring device that can reduce costs by being smaller and lighter and eliminates the need for parts such as piping, has less static pressure span fluctuation, and can easily switch input circuits.

, Means for Solving the Problems To achieve this object, the present invention provides a main body made of a block-shaped metal material, an internal chamber provided inside the main body and made of opposing spherical surfaces, and a method for measuring the internal chamber. A measuring diaphragm functioning as a movable electrode is divided into two measuring chambers into which pressure is introduced, a fixed electrode is provided on the wall of the internal chamber opposite the measuring diaphragm via an insulator, a block-shaped housing, and an internal space provided in the housing and containing the main body with a gap therebetween; and an internal space provided in the main body and the housing, each having one end connected to the measurement chamber, one midway communicating with the internal space, and the other end of the housing. A differential pressure sensor section including a communication hole opening to the outside, a pressure guide tube whose one end is connected to the other end of the communication hole and which guides the measurement pressure, and a pressure receiving block to which the other end of the pressure guide tube is respectively fixed. , a seal diaphragm provided on the outer surface of the pressure receiving block and forming a seal chamber communicating with the pressure receiving block and the impulse pipe; and a base block having a recess to which the pressure receiving block is attached and forming the seal diaphragm and the pressure receiving chamber. , a 2fl connection hole provided in the base block and having one end communicating with the pressure receiving chamber and the other end opening to the outside as a pressure receiving connection port, and a communication groove provided in the base block and provided on the circumferential surface of the rotary valve body. Normally, one of the connection holes is connected, and when adjusting the zero point, the communication groove is rotated to disconnect the one connection hole and connect the pressure receiving chamber side of the one connection hole and the other connection hole. This is a differential pressure measuring device comprising a communicating rotary type pressure equalizing valve.

In the above configuration, since the connection holes are usually in communication with each other, measurement pressure is applied from the left and right sides of the main body, and the measurement diaphragm is displaced by the differential pressure between the measurement pressures. The displacement of the measurement diaphragm differentially changes the capacitance between the fixed electrode and the measurement diaphragm, resulting in an electrical signal output corresponding to the differential pressure.

To equalize the constant inputs on both sides of the device and adjust the zero point of the device, rotate the communication groove provided on the circumferential surface of the rotary valve body to disconnect communication from one of the connection holes. The zero point of the device is adjusted after communicating the pressure-receiving chamber side with the other side of the connection hole.The main body is also placed in the internal cavity of the housing, so that one measurement pressure is applied from the outside of the main body. .

Hereinafter, a detailed explanation will be given based on examples.

<Example> FIG. 1 is an explanatory diagram of the main part of an embodiment of the present invention.

In the figure, 1 is a differential pressure sensor section.

As shown in FIG. 2, 11 is a block-shaped main body made of metal.

12 is an internal chamber provided in the main body 11 and made of opposing spherical surfaces.

Reference numeral 13 denotes a measurement diaphragm which divides the internal chamber 12 into two measurement chambers 14 and 15 and functions as a moving electrode.

Reference numerals 131 and 132 are insulating films provided on the wall surface of the internal chamber 12 and made of a plasma sprayed ceramic film, in this case having a thickness of 0.2 to 0.5 mm.

Fixed electrodes 133 and 134 are provided on the surfaces of the insulating films 131 and 132, respectively, on the wall surface of the internal chamber 12 facing the measurement diaphragm 13.

16 is a block-shaped housing, as shown in FIG.

Reference numeral 161 denotes an internal space provided in the housing 16 and housing the main body 11 with a gap therebetween.

17 is provided in the main body 11 and the housing 16, and a measurement chamber 14
．． 15 , one end is connected to the internal cavity, and the curved end is a communication hole that opens to the outside of the housing 16 .

Reference numeral 2 denotes a pressure guiding pipe whose one end is connected to the other end of the communication hole 17 and which guides the measurement pressure.

Reference numeral 3 designates pressure receiving pro-refs to which the other ends of the impulse tubes 2 are fixed.

A seal diaphragm 31 is provided on the outer surface of the pressure receiving block 3 and constitutes a seal chamber 32 that communicates with the pressure receiving block 3 and the pressure guiding pipe 2.

4 is a seal diaphragm 3 in which the pressure receiving block 3 is housed;
1 and a recess 42 forming a pressure receiving chamber 41.

Reference numerals 43 and 44 designate two connection holes provided in the base block 4, one end communicating with the pressure receiving chamber 41, and the curved end opening to the outside as a pressure receiving connection port.

In this case, the connection hole 43 is connected to the high pressure side, and the connection hole 44 is connected to the low pressure side.

5 is provided in the base block 4 as shown in FIG. 4, and normally communicates with the connection hole 44 through a communication groove 52 provided on the circumferential surface of the rotary valve body 51. During zero point adjustment,
The communication groove 52 is rotated to disconnect the connection hole 44 from the connection hole 4.
This is a rotary type pressure equalizing valve that communicates between the pressure receiving chamber 42fFI of No. 4 and the connection hole 43.

6 is a cover attached to the base block 4, covering the differential pressure sensor section 1, as shown in FIG.

Reference numeral 61 denotes a printed board unit attached to the cover 6 and having electronic components attached thereto.

Reference numerals 101 and 102 are filled liquids sealed in two chambers consisting of the measurement chambers 14 and 15, the impulse tube 2, and the seal chamber 32. In this case, silicone oil is used.

In the above configuration, since the connecting holes 43 and 44 are normally in communication with each other, measurement pressure is applied from the left and right sides of the main body 11, and the measurement diaphragm 13 is displaced by the difference in the measurement pressures. As the measurement diaphragm 13 is displaced, the capacitance between the fixed electrodes 133 and 134 and the measurement diaphragm 13 changes differentially, and an electrical signal output corresponding to the differential pressure is obtained.

To equalize the constant inputs on both sides of the device and adjust the zero point of the device, as shown in FIG. Pressure receiving chamber 4211 of connection hole 44 with communication cut off! The main body 11 is placed in the internal cavity 161 of the housing 16 so that one measurement pressure is applied from the outside of the main body 11. .

As a result, (1) Since the main body of the differential pressure measuring device and the three-way valve can be integrated, there is no need for bolts, main body flanges, brackets, etc. for installation, making it possible to reduce size, weight, and cost.

(2) Piping between the main body of the differential pressure measuring device and the three-way valve becomes unnecessary.

(3) The differential pressure sensor section 1 is separated from the base block 4 by the impulse tube 2 and supported in the air, so even if the fluid to be measured is at a high temperature, it can be measured without being affected by the temperature of the fluid to be measured. A device with a wide temperature range is obtained.

(4) Switching of the input circuit can be done with just one touch, since it is only necessary to rotate the main body 51 of the rotary valve.

(5) If a sprayed ceramic film is used as the insulating films 131 and 132, they can be made extremely thin, so there is no need to sandwich the main body 11 large, and the strength of the main body 11 can be increased, so the main body 11 can be made smaller. .

(6) Since the main body 11 is disposed in the internal cavity 161 of the housing 16, and one measurement pressure is applied from the outside of the main body 11, a static pressure with little variation in span can be obtained.

In the above-mentioned embodiment, the rotary type pressure equalizing valve 5 was described as being manually operated, but it goes without saying that it may be a remote type valve using a solenoid valve or the like.

<Effects of the Invention> As described above, the present invention comprises a main body made of a block-shaped metal material, an inner chamber provided inside the main body and made of opposing spherical surfaces, and a chamber into which measurement pressure is introduced. A measuring diaphragm functioning as a moving electrode; a fixed electrode provided on the wall of the inner chamber opposite the measuring diaphragm via an insulator; a block-shaped housing; and a main body provided in the housing. an internal space containing the internal space with a gap therebetween, and a communication hole provided in the main body and the housing, each having one end connected to the measurement chamber, one midway communicating with the internal space, and the other end opening to the outside of the housing. A differential pressure sensor section comprising: □ a pressure impulse tube whose one end is connected to the other end of the communication hole and which guides the measurement pressure; a pressure receiving block to which the other end of the pressure impulse tube is respectively fixed; a seal diaphragm provided on an outer surface and forming a seal chamber communicating with the pressure receiving block and the impulse pipe; a base block having a recess to which the pressure receiving block is attached and forming a pressure receiving chamber with the seal diaphragm; Two connection holes are provided, one end of which communicates with the pressure receiving chamber, and the other end of which opens to the outside as a pressure receiving connection port, and a communication groove provided in the base block and provided on the circumferential surface of the rotary valve body. A rotary type in which one of the connection holes is communicated and when adjusting the zero point, the communication groove is rotated to disconnect communication between the one connection hole and the pressure receiving chamber side of the one connection hole and the other connection hole. A differential pressure measuring device including a pressure equalizing valve was constructed.

As a result, (1) Since the main body of the differential pressure measuring device and the three-way valve can be integrated, there is no need for bolts, main body flanges, brackets, etc. for installation, making it possible to reduce size, weight, and cost.

(2) Piping between the main body of the differential pressure measuring device and the three-way valve becomes unnecessary.

(3) The differential pressure sensor part is extended from the base block by the impulse pipe and is supported in the air, so even if the fluid to be measured is high temperature, it is not affected by the temperature of the fluid to be measured and is within the measurable temperature range. A wide device is obtained.

(4) Switching the input circuit can be done with one touch, as all you have to do is turn the rotary valve body.

(5) Since the main body is disposed in the internal space of the housing, and one of the measurement pressures is applied from the outside of the main body, a static pressure with little variation in span can be obtained.

Therefore, according to the present invention, it is possible to realize a differential pressure measuring device that is smaller and lighter, eliminates the need for parts such as piping, reduces costs, has less static pressure span fluctuation, and has easy input circuit switching. can.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of the main part configuration of an embodiment of the present invention, FIG.
FIGS. 3, 4, and 5 are explanatory diagrams of the main part configuration of FIG. 1, and FIG. 6 is an explanatory diagram of the configuration of a conventional example that has been generally used. 1... Differential pressure sensor section, 101, 102. ... Filled liquid, 11 ... Main body, 12 ... Internal chamber, 13 ... Measurement diaphragm, 131, 132 ... Insulating film, 133.
134...Fixed electrode, 14.15...Measurement chamber, 16
...Housing, 161...Internal void, 17...
Communication hole, 2... Impulse pipe, 3... Pressure receiving block, 31
...Seal diaphragm, 32...Seal chamber, 4.
... Base block, 41 ... Pressure receiving chamber, 42 ... Recess, 43.44 ... Connection hole, 5 ... Rotary pressure equalization valve, 51 ... Rotary valve body, 52 ... Communication groove,
6... Cover, 61... Printed board unit. Figure 3 Differential pressure sensor part Figure 6

Claims (1)

[Claims] A main body made of a block-shaped metal material, an internal chamber provided inside the main body and made of opposing spherical surfaces, a measurement diaphragm that functions as a moving electrode that divides the internal chamber into two measurement chambers into which measurement pressure is introduced, and a measurement diaphragm that functions as a moving electrode. A fixed electrode provided on the wall of the internal chamber facing the diaphragm via an insulator, a block-shaped housing, an internal cavity provided in the housing and containing the main body with a gap therebetween, and the main body and the housing. a differential pressure sensor section provided with a communication hole having one end connected to the measurement chamber, one midway communicating with the internal cavity, and the other end opening to the outside of the housing; A pressure impulse tube whose one end is connected to each other and which guides the measurement pressure, a pressure receiving block to which the other end of the pressure impulse tube is respectively fixed, and a seal chamber provided on the outer surface of the pressure receiving block and communicating with the pressure receiving block and the pressure impulse tube. a base block having a concave portion to which the pressure receiving block is attached and forming a pressure receiving chamber with the seal diaphragm; and a base block provided in the base block with one end communicating with the pressure receiving chamber and the other end being connected to the outside for pressure receiving. Two connection holes that open as ports and a communication groove provided in the base block and provided on the circumferential surface of the rotary valve body normally connect one of the connection holes and rotate the communication groove when adjusting the zero point. A differential pressure measuring device comprising a rotary pressure equalizing valve that disconnects the one connection hole and communicates the pressure receiving chamber side of the one connection hole with the other connection hole.