JPH01320442A - Pressure measuring instrument - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

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

[Summary of the Invention 1 The present invention provides a pressure measuring device consisting of two chambers filled with gas for pressure measurement and a diaphragm separating the two chambers. By creating a chamber filled with the gas that will be the standard pressure sandwiched between them, and installing electrodes inside that chamber, the electrodes that were conventionally in direct contact with the gas that will be used to measure the pressure will be replaced with the gas that will be used to measure the pressure. This is to avoid direct contact with. As a result, it is possible to measure differential pressures of corrosive gases and to simultaneously measure differential pressures and absolute pressures.

[Conventional technology]

In a conventional differential pressure measuring device that detects the displacement of a diaphragm as a change in capacitance, as shown in Fig.
and a second chamber 2, and a diaphragm 20 separating these two chambers, and this diaphragm 12 is displaced by the differential pressure between the first chamber 1 and the second chamber 2. 1st
The capacitance between the first electrode 6 and the diaphragm 20 that changes due to the displacement of the diaphragm 12 is determined by the first electrode 6 provided in the room and the second electrode 7 provided in the second room. , a method was adopted in which the capacitance between the second electrode 7 and the diaphragm 20 was detected, and the differential pressure between the first chamber 1 and the second chamber 2 was detected from the difference in the respective capacitances. .

[Problem to be solved by the invention]

In the pressure measuring device described above, the electrode is installed in a room filled with the gas whose pressure is to be measured, so it comes into contact with the gas whose pressure is to be measured. When measuring , the electrodes corrode, making it difficult to perform stable measurements over a long period of time.

[Means to solve the problem]

In order to solve the above problems, in the present invention, a third chamber is provided between the first chamber and the second chamber, which are filled with the gas whose pressure is to be measured, and which is filled with the gas that is the reference pressure. The first diaphragm airtightly separates the first chamber from the third chamber, the second diaphragm airtightly separates the second chamber from the third chamber, and a capacitance is provided inside the third chamber. The structure is equipped with a group of electrodes for detecting.

[Function] According to the above configuration, the electrode group for detecting capacitance does not come into direct contact with the gas whose pressure is to be measured, and even corrosive gases can be sufficiently measured.

[Example 1 Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a sectional view showing an embodiment of the present invention.

The first chamber l and the second chamber are filled with the gas whose pressure is to be measured.
A third chamber 3 filled with gas having a reference pressure is provided between the chamber 2 and the third chamber 3, and the first diaphragm 4 airtightly separates the first chamber 1 from the third section m3. , second
The second chamber 2 and the third chamber 3 are airtightly separated by a diaphragm 5 . The wall 8 is provided at an intermediate position between the first diaphragm 4 and the second diaphragm 5, and divides the third chamber 3 into two, and the wall 8 is installed so as to equalize the pressure in the divided third chamber 3. A hole 9 for conduction is provided in the center of the hole 9 . The first electrode 6 is provided on the surface of the wall 8 facing the first diaphragm 4 so as to have a capacitance therebetween, and the second electrode 7 is provided on the surface of the wall 8 opposite to the first diaphragm 4 so as to have a capacitance therebetween.
The first electrode 6 and the second electrode 7 are insulated. The first diaphragm 4 and the second diaphragm 5 are commonly grounded, the first electrode 6 and the second electrode 7 are connected to the capacitance detection circuit IO, and the capacitance detection circuit IO is connected to the pressure detection circuit 11. ing.

FIG. 2 is a sectional view showing another embodiment of the present invention.

A first chamber l and a second chamber 2 filled with gas to be subjected to pressure measurement are partitioned by a wall 12, and a third chamber 1 is separated by a first diaphragm 4 and a second diaphragm 5.
It is airtightly separated from room 3. In the third chamber 3, a first electrode 6 and a second electrode 7 are arranged to face the first diaphragm 4 and the second diaphragm 5, respectively, and the third chamber 3 is filled with gas having a reference pressure. ing. The first diaphragm 4 and the second diaphragm 5 are commonly grounded, the first electrode 6 and the second electrode 7 are connected to a capacitance detection circuit 10, and the output of the capacitance detection circuit 10 is used for pressure detection. It is connected to the circuit 11.

The pressure measuring device according to the present invention described above operates as follows.

When a gas of unknown pressure is introduced into the first chamber 1 and the second chamber 2, the first diaphragm 4 and the second diaphragm 4 change depending on the pressure difference with the third chamber 3, which is the reference pressure. 5 are respectively displaced. Due to the displacement of the first diaphragm 4, this l-th diaphragm 4 and the first electrode 6
As the second diaphragm 5 is displaced, the capacitance between the second diaphragm 5 and the second electrode 7 changes. The difference in this change is detected by the capacitance detection circuit 10, converted into an electrical signal, and supplied to the pressure detection circuit 11. The pressure detection circuit 11 then detects the pressure difference between the gas introduced into the first chamber 1 and the gas introduced into the second chamber 2 from the electric signal representing the difference in capacitance change.

FIG. 3 is a sectional view showing another embodiment of the present invention. In FIG. 1, the first electrode 6 and the second electrode 7 provided on the surface of the wall 8 are replaced with double electrodes, respectively. It is structured.

The third electrode 13 has a capacitance between the first electrode 6 and the first diaphragm 4 and a capacitance between the third electrode 13 and the first diaphragm 4 when the displacement of the first diaphragm 4 is zero. The fourth electrode 14 is provided outside the first electrode 6 on the surface of the wall 8 facing the first diaphragm so that the capacitance between the fourth electrode 14 and the second diaphragm is equal. When the displacement of 5 is zero, the capacitance between the second electrode 7 and the second diaphragm 5 is equal to the capacitance between the fourth electrode 14 and the second diaphragm 5. The second electrode 7 is provided outside the second electrode 7 on the surface of the wall 8 facing the second tire flam 5 . The first diaphragm 4 and the second diaphragm 5 are commonly grounded, the first electrode 6 and the third electrode 13 are connected to the first capacitance detection circuit 15, and the second electrode 7 is connected to the first capacitance detection circuit 15.
and the fourth electrode 14 are connected to a second capacitance detection circuit 16, and the first capacitance detection circuit 15 is connected to the first pressure detection circuit 1.
7 and the third pressure detection circuit 19, the second capacity detection circuit 1
6 is a second pressure detection circuit 18 and a third pressure detection circuit 1
Connected to 9.

In the above configuration, the operation will be explained next.

When gas of unknown pressure is introduced into the first chamber 1 and the second chamber 2, the first tire flam 4 and the second tire flammable The diaphragms 5 are respectively displaced. Due to the displacement of the first diaphragm 4, this first diaphragm 4 and the first electrode 6
and the third electrode 13 are respectively displaced. This change in capacitance is detected by the first capacitance detection circuit 15. Also, due to the displacement of the second diaphragm 5,
The capacitances between the second tire flam 5 and the second electrode 7 and fourth electrode 14 change. This change in capacitance is detected by the second capacitance detection circuit 16.

The first capacitance detection circuit 15 supplies an electrical signal according to the detected change in capacitance to the first pressure detection circuit 17 and the third pressure detection circuit 19. Further, the second capacitance detection circuit 16 supplies an electrical signal corresponding to the detected change in capacitance to the second pressure detection circuit 18 and the third pressure detection circuit 19. The detection circuit 17 detects the pressure of the gas introduced into the first chamber 1 according to the electrical signal from the first capacity detection circuit 15, and the second pressure detection circuit 18 detects the pressure of the gas introduced into the first chamber 1. The pressure of the gas introduced into the second chamber 2 is detected in response to an electrical signal from the detection circuit 16. The third pressure detection circuit is connected to the first capacitance detection circuit 15.
And the second capacity is in circulation! The difference in each capacitance change is detected from the electrical signal from f116, and accordingly,
The differential pressure between the gas introduced into the first chamber 1 and the gas introduced into the second chamber 2 is detected.

[Effects of the Invention] As explained above, the present invention provides a reference pressure chamber between two chambers filled with gas whose pressure is to be measured, and a group of electrodes for detecting capacitance is provided there. As a result, the gas whose pressure is to be measured is separated from the electrode group, so even when measuring the pressure of corrosive gas, the electrodes will not be corroded and the pressure can be measured stably for a long period of time. Furthermore, it is possible to provide a pressure measuring device that can simultaneously measure absolute pressure or gauge pressure and differential pressure.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing one embodiment of the present invention, Fig. 2 is a sectional view showing another embodiment of the invention, Fig. 3 is a sectional view showing another embodiment of the invention, and Fig. 4 is a sectional view showing another embodiment of the invention. FIG. 2 is a sectional view showing a conventional embodiment. l...First chamber 2...Second chamber 3...Third chamber 4...First diaphragm 5...Second diaphragm 6...First electrode 7. ...Second electrode 8...Wall 9...Hole lO...Capacitance detection circuit 11...Pressure detection circuit 20...Diaphragm and above Applicant Seiko Electronic Industries Co., Ltd. Agent Patent attorney Takayuki Hayashi Figure 1 shows the fruits of 4u of the present invention. j #1 Jii Buthimi 4-9ζ1
-Front view Figure 4

Claims (1)

[Claims] Two chambers filled with the gas whose pressure is to be measured;
In a pressure measuring device consisting of a diaphragm that airtightly separates two chambers, first and second chambers are filled with gas to be measured, and there is a space between the first chamber and the second chamber. The third chamber is filled with gas at a set reference pressure.
a chamber, and first and second diaphragms that airtightly separate the first chamber, the second chamber, and the third chamber;
a group of electrodes provided in a third chamber for detecting capacitance with respect to the first and second diaphragms;
A pressure measuring device comprising: a capacitance detection circuit electrically connected to the second diaphragm and the electrode group; and a pressure detection circuit electrically connected to the capacitance detection circuit.