JPH0843221A - Diaphragm - Google Patents

Abstract

(57) [Abstract] [Purpose] By forming corrugated folds not only in the radial direction but also in the circumferential direction, greater compliance than before can be obtained, and plastic strain and hysteresis can be reduced, and the diaphragm Improve the performance of. [Structure] A diaphragm 30 is formed by combining a radial concentric circular corrugated surface and a circumferential corrugated surface. This increases the compliance of the diaphragm 30 and reduces hysteresis and plastic strain.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diaphragm used in a pressure measuring device such as a differential pressure / pressure transmitter for detecting the pressure of various process fluids.

[0002]

2. Description of the Related Art For example, when the flow rate of a fluid in a pipe is to be measured, an orifice plate is provided in the pipe to provide a fluid resistance,
In addition, the pressure difference on the downstream side is calculated and measured based on a predetermined arithmetic expression. The differential pressure / pressure transmitter used for measuring this type of differential pressure generally applies a process fluid pressure between two points to the high-pressure side and low-pressure side seal diaphragms to move the filled liquid in the detector body. Is configured to convert the strain of a semiconductor pressure sensor provided by partitioning into an electric signal and take out the electric signal (eg, Japanese Utility Model Publication No. 59-30444, Japanese Utility Model Publication 4-3244).
No.

FIG. 6 shows a conventional example of such a differential pressure / pressure transmitter, and it will be described in brief. 1 is formed by integrally joining a high pressure side body 2 and a low pressure side body 3 by an electron beam or the like. The disc-shaped detector body 4 is welded to the detector body 1, and 5 and 6 are arranged by welding the outer peripheral edge portions to the pressure-receiving side surfaces 7 and 8 on the high and low pressure sides of the detector body 1, respectively. It is the installed seal diaphragm. As materials for the seal diaphragms 5 and 6, when corrosion resistance is required, the seal diaphragms 5 and 6 are formed in a dish shape with tantalum, titanium, stainless steel, Ni-based alloy, or the like, and a central portion facing the pressure receiving side surfaces 7 and 8 is shown in FIG.
As shown in FIG. 5, a concentric circular corrugated surface is formed. For this reason, the pressure receiving side surfaces 7 and 8 are also formed in a corrugated surface having the same shape as the seal diaphragms 5 and 6. Reference numeral 9 is a center diaphragm that divides the inner chamber 10 provided at the central joint portion of the detector body 1 into two chambers, that is, a high-pressure side body inner chamber 10A and a low-pressure side body inner chamber 10B, and 11 is an upper outer periphery of the detector body 1. The header cover is welded and fixed to the header cover mounting portion 12 formed on the surface, and 13 is a pressure sensor for measuring a differential pressure incorporated in the header cover 11, and the pressure sensor 13 has a process on the front and back surfaces of the semiconductor diaphragm 14. The high pressure PH and the low pressure PL of the fluid are respectively transmitted through the pressure transmitting sealed liquids 17A and 17B such as silicon oil sealed in the sealed circuits 15 and 16 in the detector body 1. A restrictor 18 is provided in the enclosed circuits 15 and 16.
Is press-fitted and fixed, which suppresses rapid pressure fluctuations and pulsation of the process fluid, and the diaphragm 5,
6, 9 and the pressure sensor 13 are protected. In addition, 1
Reference numerals 9 and 20 denote covers that are fitted and fixed to the respective side surfaces of the detector body 1 via O-rings (not shown) to protect the seal diaphragms 5 and 6.

In the differential pressure / pressure transmitter having such a structure, when the high pressure PH and the low pressure PL of the process fluid are applied to the seal diaphragms 5 and 6, respectively, the differential pressure (PH-PL) at that time is applied. Both diaphragms 5,
6 is displaced, and the displacement causes the enclosed liquids 17A and 17B to move to displace the center diaphragm 9, and the displacement of the center diaphragm 9 is applied to the semiconductor diaphragm 14 of the pressure sensor 13 via the enclosed liquids 17A and 17B. Therefore, the semiconductor diaphragm 14 is deformed according to the differential pressure, and the amount of the deformation is converted into an electric signal and taken out to measure the differential pressure. The center diaphragm 9 constitutes an overpressure protection mechanism. For example, when an overpressure of a predetermined amount or more is applied to the seal diaphragm 5 on the high pressure side, the center diaphragm 9 is displaced to the low pressure side and the seal diaphragm 5 and the pressure receiving side surface 7 are separated from each other. 17A of the enclosed liquid between the inner chamber 10
By letting it flow out to the A side and causing the seal diaphragm 5 to bottom on the pressure receiving side surface 7, the pressure sensor 13 is prevented from being applied with a pressure higher than a predetermined force.

[0005]

By the way, in the above-mentioned differential pressure / pressure transmitter, the seal diaphragms 5, 6 and the center diaphragm 9 are usually thin-film metal plates such as phosphor bronze, beryllium copper and stainless steel. It is formed by plastically deforming by working. Also,
At that time, as shown in FIG. 7, by attaching wavy corrugations in a concentric circular shape in the radial direction, the compliance of the diaphragm is increased, in other words, the diaphragm is softened, and the linear region satisfying the load-displacement equation is widened. There is. However, in such a conventional diaphragm, due to the limit of plastic deformation of the material by drawing, it is not possible to further increase compliance or reduce plastic strain and hysteresis, and a wider linear range, There is a drawback that a diaphragm with high sensitivity cannot be obtained.

Therefore, the present invention has been made in view of the above-mentioned conventional problems, and an object thereof is to form corrugated folds not only in the radial direction but also in the circumferential direction. It is an object of the present invention to provide a diaphragm capable of achieving greater compliance than before, reducing plastic strain and hysteresis, and improving the performance of the diaphragm.

[0007]

In order to achieve the above object, the present invention provides a diaphragm used for measuring a fluid pressure, which is formed by combining a radial concentric circular corrugated surface and a circumferential corrugated surface. It is characterized by being.

[0008]

In the present invention, the corrugated folds formed in the radial direction of the diaphragm facilitate the radial bending of the diaphragm. The corrugated folds formed in the circumferential direction of the diaphragm facilitate the flexure of the diaphragm in the circumferential direction. Therefore, the diaphragm is more flexible than the conventional diaphragm in which the corrugated folds are formed only in the radial direction, in other words, the compliance is large, and the diaphragm is sensitive and displaced even to a small pressure or a differential pressure. Further, if it becomes soft, the hysteresis and plastic strain at the time of drawing are small.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on the embodiments shown in the drawings. 1 is an external perspective view showing an embodiment of a diaphragm according to the present invention, FIG. 2 is a plan view of the diaphragm, FIG. 3 is a sectional view taken along the line AA of FIG. 2, and FIG. 4 is a line taken along the line BB of FIG. FIG. 5 is a sectional view showing a part of the outer peripheral edge of the diaphragm. In these figures, a diaphragm 30 according to the present invention is a composite of a radial concentric circular corrugated surface and a circumferential corrugated surface. Here, in the case of this embodiment, the corrugated surface in the radial direction is composed of four corrugated folds formed concentrically in the radial direction, and the corrugated surface in the circumferential direction divides the diaphragm 30 into four in the circumferential direction. An example constituted by two corrugated folds is shown. In FIG. 2, a concentric solid line 31 indicates a peak of a wavy surface in the radial direction, and a solid line 32 in the radial direction passing through the diaphragm center O is a peak of a wavy surface in the circumferential direction, and a radial dotted line 33 passing through the center O of the diaphragm. Indicates the valley of the corrugated surface in the circumferential direction. Therefore, the outer peripheral edge of the diaphragm 30 forms a corrugated surface having a pitch P of 90 ° as shown in FIG.

The diaphragm 30 having such a structure
In the production of, the metal mold that compositely forms the concentric circular corrugated surface in the radial direction and the corrugated surface in the circumferential direction should be used for plastic transfer, and plastically deforms the thin-film metal plate by drawing like the conventional diaphragm. It can be easily manufactured with.

The diaphragm 30 having the above structure
In, the corrugated folds formed in the radial direction of the diaphragm 30 facilitate the radial bending of the diaphragm 30. Further, the corrugated folds formed in the circumferential direction of the diaphragm 30 facilitate the flexure of the diaphragm 30 in the circumferential direction. Therefore, the diaphragm 30 becomes softer than the conventional diaphragm having the corrugated folds formed only in the radial direction, in other words, the compliance becomes large, and the diaphragm 30 can be sensitive and displaced even with a small pressure or a differential pressure. . Further, as the softness increases, the hysteresis and plastic strain during drawing can be reduced.

[0012]

As described above, according to the diaphragm of the present invention, the diaphragm used for measuring the fluid pressure is formed by combining the radial concentric circular corrugated surface and the circumferential corrugated surface. As a result, the compliance of the diaphragm can be increased, and a highly sensitive diaphragm can be provided. Further, as the compliance increases, the hysteresis and the plastic strain decrease, so that highly accurate measurement becomes possible.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of a diaphragm according to the present invention.

FIG. 2 is a plan view of the diaphragm.

3 is a cross-sectional view taken along the line AA of FIG.

4 is a sectional view taken along line BB of FIG.

FIG. 5 is a developed view of a part of the outer peripheral edge of the diaphragm.

FIG. 6 is a sectional view showing a conventional example of a differential pressure / pressure transmitter.

FIG. 7 is a perspective view showing a conventional diaphragm.

[Explanation of symbols]

1 ... Detector body, 5 ... Wavy seal diaphragm, 6
... Wavy seal diaphragm, 7 ... Pressure receiving side surface, 8 ... Pressure receiving side surface, 9 ... Center diaphragm, 10 ... Inner chamber, 13 ...
Pressure sensor for measuring differential pressure, 14 ... Semiconductor diaphragm, 1
5 ... Enclosed circuit, 16 ... Enclosed circuit, 17A, 17B ... Enclosure liquid for pressure transmission, 30 ... Diaphragm.

Claims (1)

[Claims] 1. A diaphragm used for measuring fluid pressure, wherein a concentric circular corrugated surface in the radial direction and a corrugated surface in the circumferential direction are formed in combination.