JPS6370135A - Differential pressure measuring apparatus - Google Patents

Abstract

PURPOSE:To enable highly accuracy measurement of a differential pressure, by measuring a static pressure as well as the differential pressure to correct errors as caused by changes in the static pressure by computation. CONSTITUTION:As measuring pressures P1 and P2 are applied from the right and the left of a differential pressure measuring apparatus, a measuring diaphragm 2 displaces depending on a differential pressure as measuring pressure P1-P2. With this displacement, an electrostatic capacitance between a first or second electrode 31 or 32 and the measuring diaphragm 2 varies differentially to obtain an electrical signal corresponding to the differential pressure. On the other hand, with the static pressure of the measuring pressures P1 and P2, the dielectric constant of sealing liquids 101 and 102 varies. This variation is measured as changes in the electrostatic capacitance of the electrodes 31 and 32 to obtain an electrical signal corresponding to changes in the static pressure. Operation is performed to correct the measured value of the differential pressure by this measured static pressure, thereby correcting errors caused by static pressure changes.

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 a differential pressure measuring device capable of correcting errors caused by static pressure fluctuations.

(Prior Art) FIG. 3 is a diagram illustrating the configuration of a conventional example that has been commonly used.

In the figure, 1 is a main body made of a metal material, and 11 is an internal chamber provided in the main body. A measuring diaphragm 2 is provided in the internal chamber 11 and functions as a moving electrode by dividing the internal chamber 11 into two measuring chambers 12 and 13. 31 and 32 are absolute bodies 41 on the wall of the internal chamber 11 facing the measurement diaphragm 2.
．． A first electrode and a second electrode are attached via 42.

43.44 is the insulator 41°42 from the fixed electrode 31.32
This is an electrode lead wire drawn out through the main body 1 through the .

In the above configuration, the pressure P measured from the left and right sides of the figure of the main body 1
,,P,, the measuring diaphragm 2 is displaced by the pressure difference between the measuring pressures P, -P2. Due to the displacement of the measuring diaphragm 2, the amount of OI electricity differs between the fixed electrodes 31 and 32, and the electrical signal output corresponding to the differential pressure is changed.

(Problems to be Solved by the Invention) However, in such a device, static pressure causes zero point fluctuations and measurement differential pressure span fluctuations, resulting in measurement errors.

The present invention solves this problem.

An object of the present invention is to provide a differential pressure measuring device that can measure differential pressure to a high degree by measuring differential pressure as well as static pressure and performing correction calculations for errors caused by static pressure fluctuations. It is on offer.

(Means for Solving the Problem) In order to solve this problem, the present invention includes a main body, an internal chamber provided in the main body, and the internal chamber divided into two measurement chambers that function as movable electrodes. A measuring diaphragm, a first electrode and a second electrode respectively provided on the internal chamber wall facing the measuring diaphragm, and a differential pressure between the first electrode, the second electrode and the measuring diaphragm. is measured, a capacitance change based on static pressure fluctuation is measured between the first electrode and the second electrode, and the measured value of the differential pressure is corrected by the measured value of the static pressure fluctuation. This is the configuration of a differential pressure measuring device.

(Function) In the above configuration, when measurement pressures P, P2 are applied to the two measurement chambers, the measurement diaphragm is displaced by the pressure difference between the measurement pressures P and P2. The displacement of the measuring diaphragm differentially changes the capacitance between the measuring diaphragm and the first electrode or the measuring diaphragm and the second electrode, and an electrical signal output corresponding to the differential pressure is obtained.

On the other hand, due to static pressure fluctuations, what happens between the first and second electrodes? 1! The rate changes and the capacitance between the first and second 'tl poles changes. This ll″lI capacitance ratio capacitance change,
By correcting the measured value of the differential pressure using the static pressure fluctuation measurement value, it is possible to correct errors caused by the static pressure fluctuation.

Hereinafter, it will be explained in detail based on examples.

(Example) FIG. 1 is an explanatory diagram of the configuration of an embodiment of the present invention.

In FIG. 1, the same symbols as in FIG. 3 indicate the same functions.

Hereinafter, only the differences from FIG. 3 will be explained.

In the figure, l is a main body made of ceramic. 51
is a metal ring for fixing the measurement diaphragm 2.

52 is a metal ring for connection. 53 is a ring-shaped housing into which the main body 1 etc. are inserted and fixed. 61
．． 62 is a seal diaphragm provided on both sides of the main body 1 and forming seal chambers 63 and 64 with the main body 1. 14
．． Reference numeral 15 denotes a through hole which communicates the seal chamber 63.64 with the measurement chamber 12.13. 101.102 is measurement room 12.1
3, communicating holes 14 and 15, and seal chambers 63 and 64 are each filled with an incompressible liquid. In this case, silicone oil is used.

In the above configuration, the pressure P measured from the left and right sides of the figure of the main body l
When l+ +'2 is applied, the measuring diaphragm 2 is displaced by the differential pressure of the measuring pressure PIP2.
The capacitance between the measuring diaphragm 2 and the measuring diaphragm 2 changes differentially, and an electrical No. 13 output corresponding to the differential pressure is obtained.

On the other hand, the dielectric constant of the engraving liquid 101 and 102 changes depending on the static pressure of the measurement pressure. By measuring this change as a capacitance change between the first electrode 31 and the second electrode 32, an electrical signal output corresponding to the change in static pressure can be obtained.

By correcting the measured value of the differential pressure using this measured static pressure value, it is possible to correct errors caused by static pressure fluctuations.

As a result, it is possible to measure a highly accurate differential pressure in which errors caused by static pressure fluctuations are corrected.

FIG. 2 is a configuration explanatory diagram of another embodiment of the present invention.

In this embodiment, a side plate 7 is provided on the outer surface of the main body l.

This provides robustness against excessive measurement pressure.

(Effects of the Invention) As explained above, the present invention includes a main body, an internal chamber provided in the main body, a measuring diaphragm that divides the internal chamber into two measuring chambers and functions as a movable electrode, and a measuring diaphragm that functions as a movable electrode. a first one provided on each of the inner chamber walls facing the inner chamber wall;
measuring the differential pressure using the electrode () and the second electrode, the first electrode, the second electrode and the measuring diaphragm described in 11'iI,
A capacitance change based on static pressure fluctuation is measured between the first electrode and the second electrode, and ff1l is determined based on the static pressure fluctuation measurement value.
Since the differential pressure measuring device is configured to perform correction calculations on the measured value of the differential pressure, it is possible to measure the differential pressure with high precision in which errors caused by static pressure fluctuations are corrected.

Therefore, according to the present invention, a differential pressure measuring device that can measure differential pressure with high accuracy is realized by measuring differential pressure as well as static pressure, and performing correction calculations for errors caused by static pressure fluctuations. can do.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the configuration of one embodiment of the present invention, FIG. 2 is an explanatory diagram of the configuration of another embodiment of the invention, and FIG. 3 is an explanatory diagram of the configuration of a conventional example commonly used. . 1... Main body, 101.102... Filled liquid, 11...
・Inner room, 12.13...Measurement room, 14.15...
Communication hole, 2... Measuring diaphragm, 31... First electrode, 32... Second electric f station, 51.52... Ring, 53... Housing, 61.62... Seal diaphragm, 63.64... Seal chamber, 7... Side plate. Figure 1 Figure 3 Figure 1

Claims (1)

[Claims] a main body, an internal chamber provided in the main body, a measuring diaphragm that divides the internal chamber into two measuring chambers and functions as a moving electrode, and a first diaphragm provided on the wall of the internal chamber facing the measuring diaphragm. A differential pressure is measured by the first electrode, the second electrode, and the measuring diaphragm, and the electrostatic charge based on the static pressure fluctuation is measured between the first electrode and the second electrode. A differential pressure measuring device configured to measure a capacitance change and perform a correction calculation on the measured value of the differential pressure based on the measured value of the static pressure fluctuation.