JPS6375534A - Differential pressure measuring instrument - Google Patents

Abstract

PURPOSE:To reduce zero-point variation with temperature and to obtain high accuracy by providing a shaft and the 1st and the 2nd rings, etc., which are inserted into the shaft slidably and repel each other, and simplifying excessive pressure protection mechanism. CONSTITUTION:When measured pressure is within measurement range width, a center diaphragm (CD) 2 is not displaced. The measured pressure is therefore detected 5 differentially. Then when the measured pressure in a pressure receiving chamber 12 exceeds the measurement range width and reaches a specific value, the 1st ring 32 which is pressed by the CD 2 with force exceeding the repulsive force of the 1st ring 32 and the 2nd ring 33 comes closer to the ring 33. Further, charged liquid materials 101 and 102 flow according to the displacement of the CD 2 until seal diaphragms (SD) 41 and 42 contact a main body 1, and pressure receiving chambers 12 and 13 do not rise in pressure thereafter. Further, when the measured pressure in the pressure receiving chamber 13 exceeds the measurement range width and reaches a specific value, the CD 2 is pressed and the ring 33 is pressed by a plate 21 with the repulsive force of the rings 32 and 33 to come closer to the ring 32. Then the pressure of the pressure receiving chambers 12 and 13 do not rise after the SDs 41 and 42 contact the main body 1.

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 improvement in the overpressure protection mechanism of a differential pressure measuring device.

(Prior Art) FIG. 7 is a diagram illustrating the configuration of a conventional example that has been commonly used. An example of this type of differential pressure measuring device is US Pat. No. 3,756,085.

In the figure, 1a is a block-shaped main body, Ila is a main body l
The chamber 2a provided in the chamber a is provided in the chamber 11a, and the chamber 2a is provided in the chamber 11a.
This is a bellows that divides 1a into two pressure receiving chambers 12a and 13a. 3a is an overpressure protection mechanism, which is provided within the bellows 2a. 31a is a ring-shaped magnet. 32a is a plate made of a magnetic material that blocks the upper surface of the magnet 31a and forms a chamber 33a for the magnet 31a. 34a is play 13
2a and the free end of the bellows 28. 3
A spring 5a is arranged between the play 1□32a and the bellows 28. Seal diaphragms 41a and 42a are provided on the outer surface of the main body Ia and constitute seal chambers 43a and 44a. , 5a is a differential pressure detection mechanism provided in the main body 1a, and in this case, a semiconductor pressure detection element is used. 14a and 15a are seal chambers 4
3a, 44a and the pressure receiving chambers 12a, 13a are communicating holes. 16a, 17a are communication holes 14a, 1
5a and the differential pressure detection mechanism 5a. l
0Ia is the pressure receiving chamber 12a, i! This is a sealed liquid that fills the first through hole 15a, the connecting hole 17a, and the seal chamber 44a. 102
A is a sealed liquid that fills the pressure receiving chamber 13a, the communication hole 14a, the connection hole 16a, and the seal chamber 43a.

In the above configuration, if the measured pressures P, P2 are within the measurement range, the differential pressure detection mechanism 5a measures the differential pressure.

When the measured pressure P1 exceeds a predetermined pressure, the plate 32a is pressed and moves upward in the figure. The bellows 2a extends, the "-J inlet liquid 102 moves, the seal diaphragm 41a is backed up by the main body 1a, and the pressure does not rise any further. That is, the overpressure protection mechanism 3a operates in a snap manner.

(Problem to be solved by the invention) However, in such a device, the measurement pressure P
2. In response to excessive pressure from II, the snap action like that on the P1 side cannot be performed.

The use of two similar devices would allow snapping action in both directions, but would result in a very complex and expensive structure.

The present invention solves this problem.

An object of the present invention is to simplify the overpressure protection mechanism, reduce the number of parts compared to the conventional example, make it cheaper, and reduce the size of the overpressure protection mechanism, thereby reducing the amount of sealed liquid and increasing the temperature and volume of the sealed liquid. It is an object of the present invention to provide a differential pressure measuring device that can achieve a high t#i degree by reducing zero point fluctuations due to temperature.

(Means for Solving the Problems) In order to achieve this object, the present invention includes a block-shaped main body, a chamber provided in the main body, and two pressure receiving chambers provided in the chamber. A plate-shaped partition mechanism that divides the block into two parts, a differential pressure machine mechanism that receives the measured pressure from the 1liI pressure receiving chamber, and a seal provided on the outer surface of the 17th block that receives the measured pressure and forms a seal chamber with the block. A differential pressure measuring device comprising a diaphragm, a communication hole communicating the seal chamber and the pressure receiving chamber, and two sealed liquids filling the communication hole, the seal chamber and the pressure receiving chamber, respectively. , a shaft made of a non-magnetic material and provided perpendicular to the surface of the partition wall mechanism and having one end attached to the center diaphragm; and first and second magnets that are slidably inserted into the shaft and repel each other. a ring, a plate fixed perpendicularly to the other end of the shaft; The outer circumferential portion of the second ring is engaged and has four parts having the required dimensions! This is a configuration of a differential pressure measuring device that detects lf characteristics.

(Function) In the above configuration, when the measurement pressure is within the measurement range width,
The center diaphragm does not displace due to the repulsion of the magnet. Therefore, the differential pressure of the measured pressure is detected by the differential pressure detection mechanism.

When the measurement pressure exceeds the measurement range width and reaches a predetermined value, the center diaphragm presses the first ring with a force that exceeds the repulsive force between the first ring and the second ring, causing the first ring to approach the second ring. . Due to the displacement of the center diaphragm, a large flow of the enclosed liquid takes place. This flow continues until the seal diaphragm comes into close contact with the main body, after which the pressure in the pressure receiving chamber does not rise.

When the other measurement pressure exceeds the measurement range width and reaches a predetermined value, the center diaphragm is pressed.

Along with this, the second ring is pressed by the plate with a force that exceeds the repulsive force between the first ring and the second ring, and the second ring approaches the first ring.

Flow of the enclosed liquid occurs until the center diaphragm is displaced and the seal diaphragm is brought into close contact with the body. After the seal diaphragm comes into close contact with the main body, the pressure in the pressure receiving chamber does not increase.

Examples will be described in detail below.

FIG. 1 is an explanatory diagram of the configuration of an embodiment of the book 111.

In the figure, 1 is a block-shaped main body.

11 is a chamber provided in the main body 1, and 2 is a center diaphragm provided in the chamber 11 to divide the chamber 11 into two pressure receiving chambers 12 and 13. 21 is a plate provided on the center diaphragm. 3 is an overpressure protection mechanism, and chamber 11
It is located inside.

As shown in FIG. 2, 31 is a shaft made of a non-magnetic material, which is provided perpendicularly to the surface of the center diaphragm 2, has one end attached to the center diaphragm 2, and is made of a non-magnetic material. 32
．． Reference numeral 33 denotes first and second rings made of permanent magnets that are slidably inserted into the shaft 31 and repel each other.

A plate 34 is fixed perpendicularly to the other end of the shaft 31 and is made of a magnetic material. 41 and 42 are seal diaphragms that are provided on the outer surface of the main body 1 and constitute seal chambers 43 and 44. 45.46 is the seal diaphragm 41
．． 42 is a pack-up nest provided in the main body 1 opposite to 42. Reference numeral 5 denotes a differential pressure detection mechanism, in which a semiconductor pressure detection element is used. 14.15 is seal chamber 4
3.44 and the pressure receiving chamber 12.13 are communicating holes. Reference numerals 16 and 17 are connection holes that connect the communication holes 14 and 15 and the differential pressure detection mechanism 5. Reference numerals 61 and 62 denote covers that cover the main body 1 and the seal diaphragms 4-1 and 42 to form pressure chambers 63 and 64. +01 is seal chamber 43, communication hole 1
4. Filled liquid that fills the pressure receiving chamber 12 and the connecting hole 16. +
02 is a sealed liquid that fills the pressure receiving chamber 13, the communication hole 15, the seal chamber 44, and the connection hole 17. In this case, silicone oil is used as the filling liquid 10j, +02. In the above configuration, when the measurement pressures P, P2 are within the measurement range width, the center diaphragm 2 is not displaced due to the repulsive force between the first ring 32 and the second ring 33. Therefore, the differential pressure between the measured pressures P and P2 is detected by the differential pressure detection mechanism 5.

When the measurement pressure P1 exceeds the measurement range width and reaches a predetermined value,
The center diaphragm 2 presses the first ring with a force that exceeds the repulsive force of the first ring 32 and the second ring 33.
The ring 32 approaches the second ring 33. Due to the displacement of the center diaphragm 2, a large flow of the enclosed liquid 101 occurs. This flow continues until the seal diaphragm 41 comes into close contact with the main body, after which the pressure in the pressure receiving chamber 12 does not increase.

When the measurement pressure P2 exceeds the measurement range width and reaches a predetermined value,
Center diaphragm 2 is pressed. Along with this,
The second ring 33 is connected to the first ring 32 by the plate 34.
The second ring 33 approaches the first ring 32 as it is pressed by a force that exceeds the repulsive force between the second ring 33 and the second ring 33 . The flow of the enclosed liquid 102 occurs until the center diaphragm 2 is displaced and the seal diaphragm 42 comes into close contact with the main body.

After the seal diaphragm 42 is in close contact with the main body, the pressure receiving chamber 13
pressure does not increase.

The pressure J when the overpressure protection mechanism 3 operates is the first ring 32.
．． The material of the second ring 33 and the material of the first ring 33, 2nd ring 32.3
3 and the gap between the first ring 32 and the second ring 33 can be freely set.

The operation of the following will be described in more detail.

The differential pressure of the center diaphragm 2 is P, the effective area is A, the center displacement is X, the spring constant with respect to the displacement Let X be the initial gap between two permanent magnets. Then, the left side of the following equation is the force that tries to move the center diaphragm 2,
The first term on the right side is the center diaphragm 2 that opposes it.
The second term of the reaction force is the pressure at which the first ring 32 protector 4'g3 operates.

If the equation (+) is expressed in a graph, it will look like the one shown in FIG.

Even if the pressure JP increases from 0 to 1, no displacement of the center diaphragm 2 occurs. At point 1, when the repulsive force between the first ring 32 and the second ring 33 becomes larger than B/XO, the center diaphragm 2 starts to displace in response to the pressure. Point 2
If the displacement x2 corresponding to is the displacement when all the liquid sealed in the seal chamber is absorbed by the center diaphragm 2, then
A displacement of x2 or more (J does not occur, the amount of pressure corresponding to χ2) There is no single pressure of 2.

Next, when the pressure decreases, the flow changes from 2 to 1 to 0, which is the opposite of the case when the pressure increases.

The overpressure protection operation for one measurement pressure has been described above, but the overpressure protection operation for the other measurement pressure is similar.

As a result, the overpressure protection mechanism can be simplified by utilizing the repulsive force of the two permanent magnets. Therefore, compared to the conventional example, the number of parts can be reduced and the cost can be reduced. In addition, the aim for overpressure protection can be miniaturized and installed near the center axis of the center diaphragm, which prevents overpressure protection. Ia! The increase in internal volume due to this structure can be reduced.

Therefore, it is possible to reduce the temperature zero fluctuation caused by the temperature volumetric expansion of the sealed liquid, and it is possible to realize a differential pressure measuring device that can be highly accurate.

Although the shape of the graph in FIG. 5 changes depending on the volume of the sealed liquid and the selection of various variables, the basic operation remains the same.

FIG. 6 is an explanatory diagram of the main part configuration of another embodiment of the present invention.

In this embodiment, a piston 71 and an O-ring 72 are used instead of the center diaphragm 2 in the embodiment of FIG.
It is constructed of a partition wall mechanism 7 consisting of.

In this case, the piston 71 and the chamber 11 by the O-ring 72 etc.
When the resistance between the two is small, the relationship between the differential pressure P and the displacement X of the piston 71 is as follows: The spring constant term in equation (1) disappears, and P A = (2)'
; Becomes Co-'s.

(Effect of the invention) In order to achieve this object, the present invention includes a block-shaped main body, a chamber provided within the main body, and a plate-shaped main body provided in the chamber that divides the chamber into two pressure-receiving chambers. a seal diaphragm that receives a pressure measurement pressure and forms a seal chamber with the block; a communication hole that communicates the seal chamber and the pressure receiving chamber; In a differential pressure measuring device comprising two sealed liquids, a shaft made of a non-magnetic material is provided perpendicularly to the surface of the partition wall mechanism, one end is attached to the center diaphragm, and the shaft is slidably inserted into the shaft. first and second rings made of magnets that repel each other; a plate fixed perpendicularly to the other end of the shaft;
Record 1. By constructing a differential pressure measuring device having four parts having the required dimensions and engaged with the outer peripheral part of the second ring, it is possible to detect excessive pressure by using the repulsive force of the two permanent magnets. The pressure protection mechanism can be simplified. Therefore, compared to the conventional example, the number of parts can be reduced and the cost can be reduced. Further, since the overpressure protection mechanism can be miniaturized and installed near the central axis of the center diaphragm, the internal volume increased by the overpressure protection mechanism can be reduced. Therefore, it is possible to reduce the temperature zero fluctuation caused by the temperature volumetric expansion of the sealed liquid, and it is possible to realize a differential pressure measuring device that can be highly accurate.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the configuration of one embodiment of the present invention, FIGS. 2 to 5 are explanatory diagrams of the operation of FIG. 1, FIG. 6 is an explanatory diagram of the configuration of another embodiment of the invention, and FIG. 1 is a configuration explanatory diagram of a conventional example that has been commonly used. 1... Main body, 101.102... Enclosed liquid, 11.
... Chamber, 12.13 ... Pressure receiving chamber, 14.15 ... Communication hole, 16゜17 ... Connection hole, 2 ... Center diaphragm, 21 ... Plate, 3 ... Excess pressure Protection mechanism, 31... Shaft, 32... First ring, 33
...Second ring, 34...Plate, 41.42.
...Seal diaphragm, 43.44...Seal chamber,
45.46... Backup nest, 5... Differential pressure detection mechanism, 61.62... Cover, 63.64... Pressure chamber, 7... Bulkhead mechanism, 71... Piston, 72・
...0 ring.

Claims (1)

[Claims] A block-shaped main body, a chamber provided in the main body, a plate-shaped partition mechanism provided in the chamber to divide the chamber into two pressure-receiving chambers, and differential pressure detection that receives measured pressure from the pressure-receiving chamber. a mechanism, a seal diaphragm provided on the outer surface of the block to receive measurement pressure and form a seal chamber with the block, a communication hole communicating the seal chamber and the pressure receiving chamber, and the communication hole and the seal chamber. and two sealed liquids filled in the pressure receiving chamber, respectively, the differential pressure measuring device includes a shaft made of a non-magnetic material, provided perpendicularly to the surface of the partition wall mechanism, and having one end attached to the center diaphragm. , first and second rings made of magnets that are slidably inserted into the shaft and repel each other; a plate fixed perpendicularly to the other end of the shaft; A differential pressure measuring device characterized by comprising a recessed portion having a predetermined size and engaged with an outer peripheral portion of the second ring.