JPH01267431A - Differential pressure measuring apparatus - Google Patents

Abstract

PURPOSE:To achieve a reduction in cost, by integrating a differential pressure measuring apparatus body section and a three-way valve to allow a smaller size and a lighter weight along with elimination of a part such as piping. CONSTITUTION:A stop valve 5 is opened while an equalizer valve 6 closed to apply a measuring pressure from the right and left of the body 11, which causes a displacement of a measuring diaphragm 13 by a differential pressure of a measuring pressure. With the displacement of the measuring diaphragm 13, an electrostatic capacity of fixed electrodes 133 and 134 and the measuring diaphragm 13 changes differentially to obtain an electric signal output corresponding to the differential pressure. To adjust the apparatus to a zero point by uniformizing both the measuring inputs of the apparatus, after the equalizer valve 6 is opened, the stop valve 5 on the high pressure side is closed. Subsequently, the stop valve 5 on the low pressure side is closed to adjust the apparatus to the zero point.

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. 5 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. CI is the 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 eliminating the need for parts such as piping.

Means for Solving the Problems> To achieve this object, the present invention provides a differential pressure sensor section provided with an overpressure protection mechanism, and a differential pressure sensor section each having one end connected to the differential pressure sensor section and guiding measurement pressure. A pressure receiving block, a pressure receiving block to which the other end of the pressure receiving pipe is fixed, a seal diaphragm provided on an outer surface of the pressure receiving block and forming a seal chamber communicating with the pressure receiving block and the pressure receiving block, and the pressure receiving block. a base block having a concave portion to which the seal diaphragm and a pressure receiving chamber are attached; and two connecting holes provided in the base block, one end communicating with the pressure receiving chamber and the other end opening to the outside as a pressure receiving connection port. , a stop valve provided in the middle of the connection hole to open and close the connection hole, a pressure equalization hole that communicates with each other midway between the stop valve of the two connection holes and the pressure receiving chamber, and the pressure equalization hole. This is a differential pressure measuring device comprising a pressure equalizing valve provided in the middle of the hole.

Effect> In the above configuration, by opening the stop valve and closing the pressure equalizing valve, 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, open the pressure equalization valve, close the stop valve on the high pressure side, then close the stop valve on the low pressure side, and then close the stop valve on the low pressure side. Adjustment of the zero point will be described in detail below based on an example.

<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.

11 is a block-shaped main body made of metal.

12 is an internal chamber provided in the main body 11.

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.

Insulating films 131 and 132 are provided on the wall surface of the internal chamber 12 and are made of a plasma sprayed ceramic film. In this case, the thickness is 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 of the internal chamber 12, facing the measurement diaphragm 12.

Reference numeral 2 denotes a pressure guiding pipe whose one end is connected to the differential pressure sensor section 1 and which guides the measured pressure.

Reference numeral 3 designates pressure receiving blocks to which the other ends of the pressure guiding pipes 2 are respectively 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 the seal diaphragm 3 attached to the pressure receiving block 3
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 other end opening to the outside as a pressure receiving connection port.

As shown in FIG. 3, 5 is a stop valve provided in the middle of each of the connecting holes 43, 44 to open and close the connecting holes 43, 44.

45 is a pressure equalizing hole that communicates the two pressure receiving chambers 41 with each other.

6 is a pressure equalizing valve provided in the middle of the pressure equalizing hole 45, as shown in FIG.

Reference numeral 7 denotes a cover attached to the base block 4, covering the differential pressure sensor section 1, as shown in FIG. Reference numeral 71 denotes a printed board unit attached to the cover 7 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, the stop valve 5 is opened and the pressure equalizing valve 6 is opened.
By closing, measurement pressure is applied from the left and right sides of the main body 11, and the measurement diaphragm 13 is displaced by the differential pressure between the measurement pressures. Due to the displacement of the measuring diaphragm 13,
The capacitance between the fixed electrodes 133, 134 and the measuring 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, open the pressure equalization valve 6, close the stop valve 5 on the high pressure side, and then close the stop valve 5 on the low pressure side. As a result, (1) The main body of the differential pressure measuring device and the three-way valve can be integrated, eliminating the need for bolts, body flanges, and mounting brackets, resulting in a compact, lightweight, and cost-effective solution. You can aim for down.

(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) If a sprayed ceramic film is used as the insulating film 131, 132, it 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. .

In the above-described embodiment, the stop valve 5 and the pressure equalization valve 6 have been described as manually operated valves, but it goes without saying that they may be remote-type valves using electromagnetic valves or the like.

<Effects of the Invention> As explained above, the present invention comprises: a differential pressure sensor section equipped with an overpressure protection mechanism; a pressure impulse tube whose one end is connected to the differential pressure sensor section and which guides measured pressure; A pressure receiving block to which the other ends of the pressure pipes are 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 pressure guiding pipe; and a seal diaphragm to which the pressure receiving block is attached. a base block having a concave portion constituting a pressure receiving chamber; two connecting holes provided in the base block with one end communicating with the pressure receiving chamber and the other end opening to the outside as a pressure receiving connection port; and two connecting holes in the middle of the connecting holes. A stop valve provided in each of the connection holes to open and close the connection hole, a pressure equalization hole that communicates with each other midway between the stop valve of the two connection holes and the pressure receiving chamber, and a pressure equalization hole provided midway between the pressure equalization hole. A differential pressure measuring device was constructed, which includes a pressure equalizing valve.

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 separated from the base block by a pressure impulse tube and is supported in the air, so even if the fluid to be measured is at 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.

Therefore, according to the present invention, it is possible to realize a differential pressure measuring device that can reduce costs by being smaller and lighter and eliminating the need for parts such as piping.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of the main part configuration of an embodiment of the present invention, Fig. 2
FIGS. 3 and 4 are explanatory views of the main part configuration of FIG. 1, and FIG. 5 is an explanatory view of the configuration of a conventional example that has been generally used. 1...Differential pressure sensor section, 101.10-2. ... Filled liquid, 11 ... Main body, 12 ... Internal chamber, 13 ... Measurement diaphragm, 131, 132 ... Insulating film, 133
．． 134...Fixed electrode, 14.15...Measurement chamber, 2
... Impulse pipe, 3... Pressure receiving block, 31... Seal diaphragm, 32... Seal chamber, 4... Base block, 41... Pressure receiving chamber, 42... Recessed portion, 43.
44...Connection hole, 45...Pressure equalization hole, 5...Stop valve, 6...Pressure equalization valve, 7...Cover, printed board unit.

Claims (2)

[Claims] (1) A differential pressure sensor section equipped with an overpressure protection mechanism, a pressure impulse tube whose one end is connected to the differential pressure sensor section and which guides the measurement pressure, and a pressure receiving block to which the other end of the impulse tube is 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 pressure 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. , two connection holes provided in the base block, one end communicating with the pressure receiving chamber and the other end opening to the outside as a pressure receiving connection port, and a stop valve provided in the middle of each connection hole to open and close the connection hole. and a pressure equalization hole that communicates with the stop valve of the two connection holes and the pressure receiving chamber, and a pressure equalization valve provided in the middle of the pressure equalization hole. Device. (2) As a differential pressure sensor section, there is a block-shaped main body, an internal chamber provided inside the main body consisting of opposing spherical surfaces, and the internal chamber divided into two measurement chambers into which measurement pressure is introduced, and used as a moving electrode. A measuring diaphragm that functions, an insulating film made of a plasma sprayed ceramic film provided on the wall surface of the internal chamber, and a fixed electrode provided on the surface of the insulating film facing the measuring diaphragm. A differential pressure measuring device according to claim 1 of the utility model registration claim.