JPS58121Y2 - differential pressure transmitter - Google Patents

Description

[Detailed description of the invention] The present invention relates to a differential pressure transmitter having a pair of measurement diaphragms on both sides of the main body (1. One of the objectives is to obtain a transmission group in which

In conventional differential pressure transmitters of this type, when excessive pressure is applied, the measuring diaphragm comes into contact with the side wall of the main body, which has the same waveform as the measuring diaphragm, to prevent damage and protection due to excessive pressure.

Therefore, in order to bring the measuring diaphragm into contact with the side wall before the moving member fixed to the connecting rod connecting the pair of measuring diaphragms contacts the fixed member, the amount of displacement until the measuring diaphragm contacts the side wall is determined by the amount of displacement between the moving member and the measuring diaphragm. It is necessary to make the gap between the fixing members narrower.

On the other hand, in order to treat the gap between the moving member and the fixed member as electric capacity, this gap cannot be made too large.

As a result, the distance from the measuring diaphragm to the side wall becomes small, and the drawback is that precision machining and assembly techniques are required to achieve this.

In order to eliminate this drawback, the present invention provides a pressing spring between the internal fixing member and the main body, so that when excessive pressure is applied,
First, the movable member contacts and pushes the fixed member, and then the measuring diaphragm contacts the side wall of the body.

Hereinafter, embodiments of the present invention will be explained by A.

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

In the figure, 1 is a main body, and nest portions 1a and 1b of the main body 1 are attached to both sides by welding (sliding).

These nest parts 1a and lb have openings 2a and 2b facing outward, respectively, and these openings 2a and 2b are connected by a through hole 3.

Reference numerals 4a and 4b designate a pair of measuring diaphragms provided in the 10 parts 2a and 2b, respectively, and the peripheries of the measuring diaphragms are respectively surrounded by seal rings and rings 5.
a, 5b to nest the nest portions 1.a and 5b at the periphery of the openings 2a, 2b, respectively. 7° attached to a, lb and measuring diaphragm 4a, 4b and opening 2
A, 2b, and the side walls 6a, 6b, which are the bottom surfaces of the chambers 7a, 71), have a shading 1 and the side walls 6a, 6, respectively.
．． b is formed in the same four waveforms as the waveforms of the earphragms 4a and 4b in the measurement.

. Reference numeral 8 denotes a connecting rod inserted into the through hole 3, and the center portions of the measuring diaphragms 4a, 4b are fixed to disks 9a, 9b fixed at both ends, respectively.

Reference numeral 10 denotes a circular central plate spring attached at right angles to the center of the connecting rod 8, surrounded by a spacer 11 and a protrusion 1C of the main body 1.
and is fixed to the protruding portion 1C by welding or the like.

The central leaf spring 10 forms a moving member that moves together with the connecting rod 8, and also serves as a moving electrode.

12 a and 12 b are fixing members provided oppositely on both sides of the central plate spring 10, made of insulating material, and fixed to the main body 1.
fitted inside.

Further, the fixing member 12a is kept at a constant distance from the center plate spring 10 by the spacer 11, and a part of the fixing member 12b on the center plate spring 10 side is fitted into the protrusion 1C of the main body 1 through a notch 12C. A constant distance from the central plate spring 10 is maintained.

Furthermore, fixed electrodes 13a and 13b are provided on the surfaces of these fixed members 12a and 12b facing the central plate spring 10, respectively.
However, the distance between the fixed electrodes 13a, 13b and the central leaf spring 10 of the moving electrode is the measuring diaphragm 4a, 4
b and the distance between the disks 9a, 9b and the nest portions 1a, lb.

The electrical capacitance between the central plate spring 10, which is a moving electrode, and the fixed electrodes 13a, 13b can be differentially taken out by the lead wires 14, 15, 16.

17a and 17b are pressure springs, which are pressed between the nest portion 1a and the fixing member 12a and between the nest portion 1b and the fixing member 1.
2b, respectively, and the fixing members 12a, 12
b are pushed toward the central leaf spring 10, respectively, and the nest portion 1
A small gap is maintained between a, lb and the fixing members 12a, 12b, respectively.

18 is a sealing liquid inlet, and 21a and 21b are presser springs 17a.

17b is a communication hole that connects the chambers in which the incompressible sealing liquid 19 is supplied from the inlet 8 to the chambers 7a, 7b, the through hole 3, the central plate spring 10, and the fixing members 12a, 12b. It has a structure in which the spaces between the two are filled.

Next, the operation will be explained.

When the measuring diaphragms 4a and 4b receive pressures P and P2, respectively, the connecting rod 8 is displaced by the differential pressure PIP2, and the central leaf spring 10 is displaced.

As a result, the capacitance between the central leaf spring 10, which also serves as a moving electrode, and the fixed electrodes 13^, 13b changes, and the differential pressure P
The I P2 can be converted into an electrical signal and taken out from the lead wires 14-16.

Also, when the pressure P□ increases and the differential pressure P□-P2 becomes an excessive pressure that exceeds the differential pressure range, the central leaf spring 10 of the movable electrode contacts the fixed electrode 13b and pushes the fixed member 12b, causing the fixed member 12b to It moves against the force of the pressing spring 17b.

After that, the measuring diaphragm 4a and the disk 9a come into contact with the nest part 1a of the main body 1, and the connecting rod 8 and the central leaf spring 10
stops moving.

In this way, the fixing member 12b is connected to the pressing spring 17b.
The center plate spring 10 of the moving electrode moves against the force of
Even if the electrode contacts the fixed electrode 13b, no excessive force is applied to the fixed electrode 13b.

As a result, there is no problem even if the central leaf spring 10 contacts and pushes the fixed electrode 13b, and the amount of displacement of the measuring diaphragm 4a can be made larger than the gap between the central leaf spring 10 of the movable electrode and the fixed electrode 13b.

Similarly, when the pressure P2 increases and the absolute value of the differential pressure PI P2 becomes excessive, the central leaf spring 10
After contacting the fixed member 12a, the fixed member 12a moves, and the amount of displacement of the measuring diaphragm 4b can be larger than the gap between the central plate spring 10 of the moving electrode and the fixed electrode 138.

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

In this example, a movable electrode 20 is provided which is fixed to the connecting rod 8 separately from the central plate spring IQa, and a communication hole 21a shown in FIG.
This is an example in which a hole 22 is provided in the center plate spring 10 instead of the hole 21b, and the other parts are the same as in the previous embodiment, and the same elements are given the same reference numerals and the explanation will be omitted.

In this example, as in the previous example, when excessive differential pressure Pi P2 is applied, the movable electrode 20 contacts the fixed electrodes 13a, 13b, and then the fixed members 12a, 12b move, and the measuring diaphragms 4a, 4b The amount of displacement can be made larger than the gap between the moving electrode 20 and the fixed electrodes 13 b and 13 a.

In this way, in this invention, the central part is fixed to the connecting rod, and the peripheral part of the central leaf spring is fixed to the main body, so that the fixed member can move against the presser spring, so the structure is simple and the measurement diaphragm can be easily fixed. The amount of displacement can be made larger than the gap between the fixed electrode and the movable electrode, and the practical effect is great.

In the embodiments described above, the moving electrode 10.20 and the fixed electrodes 13a, 13b are used to convert the differential pressure P□-P2 into an electrical signal. Of course, the conversion can be made by using a coil and a core instead of , or by using a coil and a non-magnetic conductive metal.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing an embodiment of the present invention, and FIG. 2 is a longitudinal sectional view showing another embodiment of the invention. 1: Main body, la, lb: Nest part of main body 1, 2a2b
: Opening, 3: Through hole, 4a, 4b: Measuring diaphragm, 8: Connecting rod, 10, 10 a: Central leaf spring (movable member), 12 a, 12 b: Fixed member, 17a, 1
7b: Pressing spring, 20: Moving electrode (moving member).

Claims (1)

[Scope of utility model registration request] a main body provided with a through hole penetrating through openings on both sides; a pair of measuring diaphragms 1 provided at the mouth of the main body; and a pair of measuring diaphragms 1 inserted into the through holes. ,
a connecting rod that connects the ρ-measurement diaphragm, a moving member fixed to the connecting rod, and a pair of fixing members that are loosely fitted into the main body and provided on opposite sides of the moving member, respectively; In the differential pressure transmitter including an electrical means for converting displacement of the movable member relative to the pair of fixed members into an electrical signal, a presser spring is provided between the pair of fixed members and the main body, respectively. A differential pressure transmitter characterized by: