JPS6366429A - Differential pressure measuring apparatus - Google Patents

Abstract

PURPOSE:To obtain an over-range protective mechanism having certain and good accuracy, by forming a center diaphragm so as to take a tray shape turning in reverse directions on the outer and inner peripheral sides thereof and to have a bent part. CONSTITUTION:When measuring pressures are applied to respective seal diaphragms 3, 4, said measuring pressures are transmitted to a differential pressure detection mechanism 5 through seal liquids 101, 102 to measure the differential pressure of both measuring pressures. When the differential pressure is within a definite range, a center diaphragm 23 does not almost displace. Therefore, the differential pressure necessary for the displacement of the diaphragms 3, 4 is almost close to zero. When the differential pressure reaches the definite range or more, the diaphragm 23 displaces suddenly and the diaphragms 3, 4 displace by said displacement and the seal diaphragm on a side high in the measuring pressure is closely adhered to a main body 1. Since pressure equal to or more than the pressure at the time of close adhesion is not applied to the differential pressure detection mechanism 5, over range protecting operation is certainly performed. When the differential pressure equal to or more than definite pressure is removed, the center diaphragm returns to the original state by the forces of springs 81, 82.

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 overpressure protection mechanism.

(Prior Art) FIG. 4 is a diagram illustrating the configuration of a conventional example that has been commonly used. An example of this type of device is Japanese Patent Publication No. 57-1711N.

In the figure, 1 is a block-shaped main body, 11 is an internal chamber provided in the main body, and 2 is an internal chamber 11 that receives two pressures x+3.
3 and 4, which are the center diaphragms divided into N, are the main body L.
It is a seal diaphragm that is provided on the outer surface of the main body 1 and forms a seal chamber 31.41, and receives measurement pressures P, , P,. 14.15 is the seal chamber 31°41 and the pressure receiving chamber 12.
These are communication holes that communicate with each other. Reference numerals 16 and 17 are connection holes that connect the communication holes N, +5 and the differential pressure detection mechanism 5. In this case, a semiconductor detection element is used for the differential pressure detection mechanism 5. Reference numerals 61 and 62 designate covers that respectively form the seal diaphragms 3 and 4 and constitute the seal diaphragms 3 and 4 and the cover g6314. ■1.1112
is a pressure receiving chamber! 2. N, seal chamber 31, 41 and communication hole 14
．． 15 and connecting holes 16 and 17,
Each is filled with fill fluid. Filled liquid 111+, I
In this case, silicone oil is used as N.

In the above configuration, when measurement pressures PI and P* are introduced into the cover chambers 63 and 64, respectively, the measurement pressures P1°P and 2 are transmitted to the differential pressure detection mechanism 5 via the sealed liquids 101 and 102, and the measurement pressures P+ , Pa is measured.

In this case, when a differential pressure is applied to the center diaphragm 2, the differential pressure and volume change (volume that the diaphragm deforms) are as shown in Figure 5, and when the differential pressure PC is applied, the volume becomes will occur.

The seal diaphragms 3 and 4 are deformed due to the movement of the sealed liquid due to this deformation, and this characteristic is as shown in FIG.

Therefore, in order for the seal diaphragms 3 and 4 to have the same volume change as the center diaphragm 2, a pressure difference of Pa1 is generated. Therefore, if the differential pressure applied to the main body 1 is ΔP, then ΔP-(2X P B,)
Pc (2 P since there are seal diaphragms on both sides)
B+) becomes the differential pressure applied to the differential pressure detector 1j45. For this reason, the characteristics of the center diaphragm 2 and the seal diaphragms 3 and 4 are not linear as shown in FIG. 5 and FIG.

FIG. 7 is an improved example of the conventional example shown in FIG. 4.

In the figure, the same symbols as in FIG. 4 indicate the same functions.

Hereinafter, only the differences from FIG. 4 will be explained.

Ill, +12 are two internal chambers provided in the main body. 21.22 is the inner chamber 1. +12, respectively, with a center diaphragm provided in the inner chamber II+,
+12 to pressure receiving chamber H1, +22 and pressure receiving chamber 1:11. IN
Divide into 7 is a spring finger as shown in FIG. 8, which is attached to the center diaphragm 21. It is arranged on one side of H as shown in FIG. 18 is the pressure receiving chamber 121 and the pressure receiving chamber! This is a communication hole that communicates with 31. 19 is a pressure receiving chamber 122 and a pressure receiving chamber 132
It is a communication hole that communicates with

In something like this. Center diaphragm 21.
22, the volume change of the seal diaphragm ■ and the differential pressure p,
Characteristic diagrams of pB are shown in 1'% Figures 9 and 10.

As described above, in this conventional example, the center diaphragm 21, 22 has a characteristic that it hardly deforms until a certain pressure difference is applied, but changes rapidly when the pressure difference exceeds the certain pressure. Therefore, even if the maximum measured differential pressure PC is applied to the center diaphragm 21, 22, the amount of change in volume is as small as . Therefore, the seal diaphragm 3
, 4 is also very small at PB2'0.

As a result, the output error is also very small and good characteristics can be obtained.

(Problem to be solved by the invention) However, in such a device, there are four pressure receiving chambers.
Since they are separated into individual parts, the structure becomes very complicated. In particular, it is difficult to process and assemble the passage for the sealed liquid that communicates the pressure receiving chambers, which increases the cost and makes it expensive.

The present invention focuses on this problem.

An object of the present invention is to provide a differential pressure measuring device that is highly accurate, inexpensive, and provides a reliable overrange protection mechanism.

(Means for Solving the Problems) In order to achieve this object, the present invention includes a block-shaped main body, an internal chamber provided in the main body, and a center that divides the internal chamber into two pressure receiving chambers. a diaphragm, a seal diaphragm provided on the outer surface of the main body that forms a seal chamber with the main body and receives measurement pressure, a communication hole that communicates the seal chamber and the pressure receiving chamber, and the communication hole and the seal chamber. In the differential pressure measuring device, the center diaphragm is provided with two sealed liquids that fill the pressure receiving chamber and a differential pressure detection mechanism that detects the differential pressure by guiding the liquids to both sides, respectively. A differential pressure measuring device characterized by having a dish-shaped side and an inner peripheral side in opposite directions, having a bent part, and a spring provided between the bent part and the wall of the pressure receiving chamber. This is a 4t4 version.

(Function) In the above configuration, when measurement pressure is applied to each seal diaphragm, the measurement pressure is transmitted to the differential pressure detection mechanism via the sealed liquid, and the differential pressure between the measurement pressures is measured.

Therefore, when the differential pressure is within a certain range, the center diaphragm hardly moves. Therefore, the differential pressure required to displace the seal diaphragm is also almost zero.

When the differential pressure exceeds a certain range, the center diaphragm rapidly displaces, and this displacement causes the seal diaphragm to displace, and the seal diaphragm on the side where the measured pressure is greater comes into close contact with the main body. Since pressure greater than the pressure at the time of close contact is not applied to the differential pressure detection mechanism, the overrange protection operation is reliably performed.

When the differential pressure above a certain pressure is removed, the force of the spring returns it to its original state.

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

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

In the figure, the same symbols as in FIG. 4 indicate the same functions.

Hereinafter, only the differences from FIG. 4 will be explained.

23, as shown in FIG. 2, the outer circumference @ 231 and the inner circumference side 23
2 is a center diaphragm having a dish shape in the opposite direction and having bent portions 233 and 234. 235.2N is a rigid portion provided at the bent portion 233.234. 81°8
2 is a spring provided between the bent portion 233, 234 and the wall of the pressure receiving chamber 12, 13.

In the above configuration, when measurement pressures p, , p, are introduced into the cover chambers 63, 64, respectively, the measurement pressures P1 and P2 are transmitted to the differential pressure detection mechanism 5 via the sealed liquid +fi+, +02, and the measurement pressure p , , p, is measured.

In this case, when a differential pressure is applied to the center diaphragm 23, the differential pressure Pd and the amount of change in volume (2) are as shown in FIG.

When the difference J'EPd is within the range of Pd to Pd, there is almost no displacement of the center diaphragm 23, and therefore the differential pressure PB required for the displacement of the seal diaphragms 3 and 4 is also almost zero. Therefore, the error in the input/output characteristics is small.

When the differential pressure Pd falls outside the range of Pd, to Pd, the center diaphragm 23 is rapidly displaced, and the seal diaphragm on the side where the measured pressure is larger comes into close contact with the main body 1.

Since a pressure higher than the pressure at the time of close contact is not applied to the differential pressure detection mechanism 5, overrange protection is reliably performed.

When the differential pressure Pd returns to within Pd+''-Pda, the center diaphragm 23 returns to its original state due to the force of the spring $1.H.

As a result, ■ A small input/output characteristic error can be obtained.

■ Enables reliable overrange pressure protection.

■ Since the center diaphragm 23 is only one piece and divided into two chambers, it is simpler than the conventional example shown in Fig. 7, and does not require a complicated sealing liquid passage as in the conventional example. . Therefore, a differential pressure measuring device that is easy to manufacture and inexpensive can be obtained.

■ The amount of sealed liquid can be significantly reduced, and errors caused by expansion and contraction of the sealed liquid due to temperature changes can be kept to a minimum.

Although it has been explained that the differential pressure detection mechanism 5 uses a semiconductor detection element, it is not limited to this, and the principle structure does not matter, but it is preferable to have a structure that is less deformed due to differential pressure. Of course.

Also, since differential pressure and overrange pressure are applied from either the left or right side of the main body 1, the center diaphragm 23
requires characteristics on both sides as shown in FIG. However, the values of Pd, , Pd, may differ depending on the characteristics of the differential pressure detector fM5. In this case, it can be set arbitrarily by changing the position of the rigid body part 236 at the center of the center diaphragm 23.

Further, the rigid body portions 235 and 236 have springs 81. It goes without saying that the rigid body parts 235 and 236 may not be provided since they are for receiving H. In that case, the outer peripheral side 23
1 and the inner peripheral side 232 are continuous, and the center diaphragm 2
3.

(Effects of the Invention) As explained above, the present invention has a block-shaped main body,
an internal chamber provided within the main body; a center diaphragm that divides the internal chamber into two pressure receiving chambers; and a seal diaphragm provided on the outer surface of the main body that forms a seal chamber with the main body and receives measurement pressure. , a communication hole communicating the seal chamber and the pressure receiving chamber, and the communication hole and the seal chamber m
In the differential pressure measuring device, the center diaphragm is connected to the outer periphery of the pressure-receiving chamber. A differential pressure measuring device characterized by having a dish-shaped side and an inner peripheral side in opposite directions, having a bent part, and a spring provided between the bent part and the wall of the pressure receiving chamber. With this configuration, a device with small input/output characteristic errors can be obtained, and reliable overrange pressure protection can be achieved.

Since only one center diaphragm is required, a complicated liquid-sealing passage is not required, and manufacturing is easy and inexpensive.

Since the amount of sealed liquid can also be significantly reduced, the occurrence of humidity errors due to the sealed liquid due to temperature changes can be suppressed to a small level.

Therefore, according to the present invention, the accuracy is good, the inexpensive
Moreover, it is possible to realize a differential pressure measuring device that provides a reliable overrange maintenance mechanism.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the configuration of one embodiment of the present invention, and FIG.
3 is an explanatory diagram of the main parts of the figure, FIG. 3 is an explanatory diagram of the operation of FIG. 1, and FIG. 4 is an explanatory diagram of the configuration of a conventional example commonly used.
5 and 6 are explanatory diagrams of the operation of FIG. 4, FIG. 7 is an explanatory diagram of the configuration of another conventional example commonly used, and FIG.
Is the diagram f? ! Main part t74 construction explanatory diagram of Fig. 7, Fig. 9, Fig. 10
The figure is an explanatory diagram of the operation of FIG. 1... Main body, 101.102... Filled liquid, 11...
・Inner chamber, 12゜13... Pressure receiving chamber, 14.15...
Communication hole, N, +7... Connection hole, 23... Center diaphragm, 231... Outer circumferential side, 232... Inner circumferential side, 233.234... Bent part, 235.23...
Rigid body part, 3.4... Seal diaphragm, 31. '4
DESCRIPTION OF SYMBOLS 1... Seal chamber, 5... Differential pressure detection mechanism, 61.6... Cover, 63.64... Cover chamber, 81.82...
··spring. Figure 5 Figure 6 Figure 7 Figure θ

Claims (1)

[Claims] a block-shaped main body; an internal chamber provided within the main body;
A center diaphragm that divides the internal chamber into two pressure receiving chambers, a seal diaphragm provided on the outer surface of the main body that forms a seal chamber with the main body and receives measurement pressure, and communicates the seal chamber and the pressure receiving chamber. a communication hole, and two sealed liquids filling the communication hole, the seal chamber, and the pressure receiving chamber, respectively;
In the differential pressure measuring device, the center diaphragm has a dish shape with an outer circumferential side and an inner circumferential side in opposite directions, and a bent portion. A differential pressure measuring device comprising: a spring provided between the bent portion and a wall of the pressure receiving chamber.