JPS6070330A - Differential pressure transmitting device - Google Patents

Abstract

PURPOSE:To make errors due to temperature change almost zero and to improve reliability, by forming pressure detecting chambers at the central part of a body, and forming a high pressure chamber and a low pressure chamber at both side- parts of the body. CONSTITUTION:A movable electrode 3 comprising a flat plate spring is provided at the central part of a body 2. Pressure detecting chambers 2a are formed at the central part of the body 2 by flanges 3a of the movable electrode 3. Flanges 7 and 8 are attached to both sides of the body 2. A high pressure chamber 9 and a low pressure chamber 10 are formed by the inner recess parts of the flanges 7 and 8 and the recess parts at the side surfaces of the body 2. In this differential pressure transmitting device, errors due to temperature change can be made almost zero, and reliability can be enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) The invention in the field of industrial application relates to a capacitive differential pressure transmitter.

(B) Prior Art Conventionally, a differential pressure transmitter has a body b provided with a pressure detection chamber a, with flanges C attached to both sides of the body b, as shown in FIG. A fixed electrode C is provided on the side of the body b, while a high pressure chamber f is provided on both sides of the body b.
and a low pressure chamber g are formed.

A seal diaphragm 1 is provided between the high pressure chamber f and the low pressure chamber g, and a silicone oil L/i is inserted into one side of the seal diaphragm 1 through a communication path j across the pressure detection chamber a. There is something that has been done.

Then, process pressure acts on the high pressure chamber f and the low pressure chamber g,
This process pressure acts on the pressure detection chamber a through the spring diaphragm l+ and the silicon oil vi, and the movable electrode d is displaced by the differential pressure of the process pressure, and the gap with the fixed electrode C changes. The capacitance change due to this gap change is derived as a detection signal.

However, in this differential pressure transmitter, silicon oil) V
Since the pressure is transmitted by enclosing i, there is a problem in that it is susceptible to the influence of ambient temperature. If the silicone oil expands due to a rise in temperature, the movable electrode (
The amount of inclusion differs on the image side.

This results in a temperature error, and furthermore, an error also occurs if the effective areas of the two seal diaphragms I+, ]+ are different, resulting in a problem of low reliability.

Furthermore, if foreign matter gets mixed in when filling the silicone oil 1, malfunctions are likely to occur, especially.

The space between the movable electrode d and the periphery of the pressure detection chamber a is extremely narrow;
There was a problem in that if foreign objects entered the system, it would cause malfunctions and could not be repaired, so it would have to be disposed of.

(c) Purpose This invention was made in view of this point.

The movable electrode is formed by a thick plate spring, and the pressure is similar to that of the pressure receiving plate.
A differential pressure transmitter that transmits data through a rod and is filled with inert gas to virtually eliminate the effects of temperature changes and at the same time reliably prevent malfunctions due to foreign matter contamination. The purpose is to provide

) configuration This invention aims to achieve the above-mentioned objects.

A pressure detection chamber is formed in the medium heat part of the body.

Flanges are attached to both sides of the body, and a high pressure chamber and a low pressure chamber are formed between the flanges on both sides of the body, and the high pressure chamber and the low pressure chamber are connected to the pressure detection chamber by a communication path, A fixed electrode is provided on the side surface of the pressure detection chamber, and a movable electrode composed of a thick plate spring is provided in the medium heat section to partition the pressure detection chamber into left and right sides, and two rods are provided in the center of the movable electrode. The rod is connected to the side and passes through the communication path, and a pressure receiving plate consisting of a large diameter flat plate is attached to the tip of the high pressure chamber and the low pressure chamber, and the peripheral edge of the pressure receiving plate and A pool diaphragm is provided between the peripheries of the high-pressure chamber and the low-pressure chamber, the inside of the pressure receiving plate is sealed to fill inert gas across the pressure detection chamber, and a bypass path is bored between the two ronds. The movable electrode is provided so that both sides of the movable electrode communicate with each other, and the movable electrode is configured to be displaced by a pressure difference between pressures acting on both pressure receiving plates.

(E) Example Hereinafter, an example of this one-blade device will be described in detail based on the drawings.

As shown in FIG. 2, 1 is a differential pressure transmitter.

It uses changes in capacitance to detect differential pressures in various processes.

This differential pressure transmitter 1 has a symmetrical structure, and a movable electrode 6 made of a flat spring is provided in the center of a body 2, and a pressure detection chamber 2+1 is formed in the center of the body 2 by a flange 6a of the movable electrode B. has been configured.

The movable electrode 6 divides the pressure detection chamber 2a into a high pressure side and a low pressure side, and a fixed d-pole 4 facing the movable electrode B is attached to the side surface of the pressure detection chamber 2a via an insulator 5. Lead wires 6 are connected to both electrodes 6 and 4, respectively.

Two communication passages 2b and 2c are bored in the body 2 from the pressure detection chamber 2a toward both sides. Further, flanges 7 and 8 are attached to both sides of the body 2, and a high pressure chamber 9 and a low pressure chamber 10 are formed by the inner recesses of the flanges 7 and 8 and the side recesses of the body 2. The high pressure chamber 9 and the low pressure chamber 10 are connected to the pressure detection chamber 2a through the opening of the communication passage 2J2c, and are formed to have a larger diameter than the communication passage 21) and 2G, and are bored in each flange 7.8. High pressure PH and low pressure PL are introduced through pressure introduction paths 7a and 8a.

At the center of both sides of the movable electrode 6 are two rondos 11.1.
2 are arranged side by side. Both rods 11, 12
passes through each communication passage 213.20.

The tip faces the high pressure chamber 9 and the low pressure chamber 10. and,
A pressure receiving plate 16° 14 is connected to the tip of this rod 11112. Both pressure receiving plates 1114 are: Rod 1.1
．． It is formed from a flat plate with a diameter larger than 12.

It is located inside the high pressure chamber 9 and the low pressure chamber 10 and receives high pressure PR and low pressure PL.

In addition, the peripheral edges of the pressure receiving plates 13 and 14, the high pressure chamber 9 and the low pressure chamber 1
Seal diaphragms 15 and 16 are stretched between the peripheral edges of the pressure receiving plates 13 and 14, and the insides of the pressure receiving plates 13 and 14 are sealed.

An inert gas 17 (for example, nitrogen gas) is filled in the sealed communication paths 2b, 2c and the pressure detection chamber 2a.

The seal diaphragms 15, 16 are formed in a corrugated shape having only one peak, and are designed to prevent two-sided pressure.

Further, a bypass path 18 is formed between the rods 11 and 12 by passing through the movable polarization 5, and the high pressure side and low pressure side of the pressure detection chamber 2a divided by the movable electrode 3 are communicated with each other, and the inert gas is connected to the high pressure side and the low pressure side. 17 is configured to be able to flow in and out freely.

Next, the differential pressure detection operation will be explained.

First, the high pressure PH and the low pressure PL act on the high pressure chamber 9 and the low pressure chamber 10 through the introduction path 7a (HL) of the flange 7.8, and each pressure receiving plate 13.14 receives pressure.

Then, the rods 11.12 are each pressed inward, and the rods 11.12 are moved by the differential pressure between the high pressure PH and the low pressure PL, and the differential pressure is converted into movement of the rods 11.12.

This movement of the rods 11, 12 causes the movable electrode 6 to be displaced. Since the movable electrode 6 is composed of a flat plate splinter, it bends, and this bending changes the gap between it and the fixed electrode 4.

The capacitance change due to this gap change is derived via the lead wire 6 and transmitted as a detection signal.

In this differential pressure transmitter 1, even if the ambient temperature etc. change, the high pressure PR and low pressure will melt, the pressure receiving plates 13, 14 and the rod 11
, 12 to the movable electrode 6, and since the inert force 17 moves via the bypass path 8, the movable electrode 6 is not affected in any way. This inert gas 17 protects each electrode 3.4.

(f) Effect As described above, according to the differential pressure transmitter of this invention, the differential pressure is transmitted to the movable electrode by the movement of the rod via the pressure receiving plate, so the conventional sealed liquid such as silicone oil is not required. Therefore, since the electrodes are protected with inert gas and this inert gas can be moved through a bypass path, errors due to temperature changes can be almost completely eliminated and reliability can be improved.

In addition, since the contamination of foreign matter as in the conventional method can be prevented, it is possible to prevent ll + poor production and defects.

[Brief explanation of the drawing]

FIG. 1 is a central vertical sectional view showing a conventional differential pressure transmitter. FIG. 2 is a central longitudinal sectional view of a differential pressure transmitter showing one example of the invention. 1: Differential pressure transmitter, 2: Body, 2a: Pressure detection chamber,
2b/2C: Communication path, 6: Movable electrode, 4: Fixed electrode, 7/8: Flange. 9: High pressure chamber, 10: Low pressure chamber, 11/12: Rod, 16
・14: Pressure receiving plate. 15/16: Seal diaphragm. 17: Inert gas, 18: Bypass path. Patent applicant Shimadzu Corporation Representative Patent attorney Shigeru Nakamura

Claims (2)

[Claims] (1) A pressure detection chamber is formed in the center of the body, and flanges are attached to both sides of the body, and a high pressure chamber and a low pressure chamber are formed between the flanges on both sides of the body. A low pressure chamber and a low pressure chamber are connected to the pressure detection chamber by a communication path, while a fixed electrode is provided on the side of the pressure detection chamber, and a movable electrode made of a thick plate spring is installed in the medium heat section to connect the pressure detection chamber to the left and right. Separated and set up. Two rods are connected laterally in the center of the movable electrode, and the rod passes through the communication path, and a pressure receiving plate consisting of a large diameter flat plate at the tip is located in the high pressure chamber and the low pressure chamber. A seal diaphragm is provided between the periphery of this pressure receiving plate and the peripheries of the high pressure chamber and the low pressure chamber, and the inside of the pressure receiving plate is sealed so that an inert gas furthermore, a bypass path is bored between both the rods so that both sides of the movable electrode communicate with each other,
A differential pressure transmitter characterized in that a movable electrode is displaced by a differential pressure between pressures acting on both pressure receiving plates. (2) The seal diaphragm is formed in a waveform having only one peak.
Differential pressure transmitter described in section.