JP2011252739A - Pressure detecting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pressure detecting device capable of preventing the degradation of accuracy even if over pressure exceeding a permissible overload is applied, and suppressing the retaining of measured fluid.SOLUTION: An installation hole 1A is formed in the inside of a case 1 formed with a pressure receiving surface 1C on one surface, and a base plate 20 is fixed in the installation hole 1A of the case 1. A diaphragm 21 is oppositely disposed to the base plate 20, and a displacement detecting portion 22 for detecting the displacement of the diaphragm 21 is provided on the diaphragm 21 and the base plate 20. A barrier 23 is closely provided on a surface opposite to the surface opposing the base plate 20 of the diaphragm 21, and an outer peripheral portion 23A of the barrier 23 is fixed to a recessed portion 1D in the case 1. The barrier 23 is disposed so as to be flush with the pressure receiving surface 1C of the case 1, and a stress absorbing portion 23C absorbing stress is provided between the outer peripheral portion 23A and a center portion 23B contacting with the diaphragm 21.

Description

  The present invention relates to a pressure sensor and other pressure detection devices used in the field of food industry and the like.

In the field of the food industry, a pressure sensor whose wetted surface is made of, for example, stainless steel (SUS316L) is required for hygienic reasons. This is due to the mechanical response to the excessive overpressure of the measurement body and the characteristics that can withstand the chemical substances contained in the measurement body. The chemical industry also requires special requirements for chemical resistance at the wetted parts of the pressure transmitter.
In response to these requirements, in general, the wetted surface is made of a stainless steel (SUS316L) diaphragm, and silicon or the like is used for pressure transmission between the detection part for detecting pressure and the stainless steel (SUS316L) diaphragm. A pressure sensor enclosing a liquid was used.
However, with this type of pressure sensor, the process of filling the liquid takes time and cost, and there are problems such as the outflow of liquid when the stainless steel diaphragm is damaged and the influence of thermal expansion due to the temperature of the pressure transmission liquid. It was.

  In order to solve these problems, conventionally, a sensor element having a diaphragm for detecting pressure and a fixing means for fixing the sensor element to the housing are provided, and a diaphragm for closing the housing is provided. There is a pressure sensor that has a solid material between them and transmits the pressure (Patent Document 1). In this pressure sensor, a shoulder is formed in the housing, and the sensor element is pressed by a fixing means so as to abut on the shoulder. The outer peripheral portion of the diaphragm is joined to the shoulder portion of the housing, and this diaphragm receives the measurement pressure in a state where it is depressed from the pressure receiving surface of the shoulder portion.

As another conventional example, a diaphragm that is provided in a case and deforms by receiving fluid pressure, a deformation of the diaphragm is converted into an electric signal, and a strain gauge provided in the diaphragm receives an overpressure exceeding an allowable overload value. There is a pressure sensor provided with a screw that restricts excessive deformation of the diaphragm (Patent Document 2).
In this pressure sensor, the screw can be brought into contact with the central portion where the diaphragm is displaced most in order to prevent overpressure, and the central portion of the diaphragm that comes into contact with the tip of the screw is formed thicker than the peripheral portion. Yes. Further, the pressure receiving surface of the diaphragm is disposed so as to recede from the surface of the case that contacts the fluid.

Japanese Patent No. 2774267 Japanese Patent No. 4233809

  In the conventional example shown in Patent Document 1, although no liquid is used for pressure transmission, a fixing means for fixing the sensor element to the housing is provided, and the diaphragm receives pressure while being recessed from the shoulder of the housing. Therefore, a step is generated between the diaphragm and the shoulder portion of the housing, and a flash surface shape cannot be formed. For this reason, the level difference increases the retention of the measurement fluid, resulting in sanitary problems.

  In the conventional example shown in Patent Document 2, liquid is not used for pressure transmission, but as a countermeasure against overpressure, it is configured to receive at one point of a screw that regulates excessive deformation of pressure received by the diaphragm. Therefore, a stress concentration portion is generated in the diaphragm, which may cause a measurement error particularly in the case of strain detection. And since the strain gauge is used as a pressure detection method, especially in the fixing of a clamp used for fixing a measuring instrument in the food industry, problems such as an output change occur due to the tightening force. In addition, in order to reliably control excessive deformation of the diaphragm with a screw when overpressure occurs, the thickness of the central part where the screw of the diaphragm abuts is compared with the thickness of the other peripheral part. Since the thickness is increased, a step occurs on the pressure receiving surface of the diaphragm, and a flash surface shape cannot be formed. For this reason, as in Patent Document 1, the measurement fluid stays larger, which causes a sanitary problem.

  An object of the present invention is to provide a pressure detection device that does not cause a decrease in accuracy even when an overpressure exceeding an allowable overload is applied, and can reduce the retention of fluid to be measured.

  The pressure detection device of the present invention includes a case in which a mounting hole is formed inside and a pressure receiving surface is formed on one surface, a substrate fixed to the mounting hole of the case, and a diaphragm disposed to face one surface of the substrate And a displacement detector provided on the diaphragm and the substrate for detecting displacement of the diaphragm, and a peripheral portion provided on the case opposite to the surface of the diaphragm opposite to the substrate. The diaphragm is disposed so as to be flush with the pressure receiving surface of the case, and is an area outside the area in contact with the diaphragm and inside the area in contact with the case. The region has a stress absorbing portion that absorbs stress.

In the present invention having this configuration, when the case is clamped to fix the pressure detection device to the installation portion, the outer peripheral portion of the diaphragm fixed to the case is distorted together with the case. Since the stress due to the distortion is absorbed by the portion, the case distortion due to the clamp tightening is hardly transmitted to the diaphragm, and the output change at the time of the clamp tightening can be reduced.
When the fluid to be measured is introduced in the pressure detection device installed in the installation part, pressure is generated on the pressure receiving surface and the diaphragm of the case. When the diaphragm is displaced together with the diaphragm, the displacement is detected by the displacement detection unit. Is done. In the present invention, the displacement is transmitted to the diaphragm through the diaphragm, and no liquid is present as the pressure transmitting member. Therefore, the time for injecting the liquid can be omitted, and the manufacturing cost of the apparatus is reduced. The pressure-receiving surface of the diaphragm and the pressure-receiving surface of the case are flush with each other, and the diaphragm is in surface contact with the diaphragm, so that the measurement surface can be made into a flash surface. For this reason, the retention of the measurement fluid can be reduced, and a sanitary problem can be avoided. Further, since the diaphragm is in intimate contact with the diaphragm and the diaphragm is opposed to the substrate, even if an overpressure exceeding the allowable overload is applied to the diaphragm and the diaphragm, the substrate is in contact with the surface to provide backup and improve the pressure resistance characteristics. In addition, as the pressure is introduced, the inner region partitioned by the stress absorbing portion of the diaphragm and the diaphragm in contact with the inner region are displaced, but the stress absorbing portion is a region outside the inner region in contact with the diaphragm. Therefore, the displacement between the inner region of the diaphragm and the diaphragm is not hindered by the pressure absorbing portion. In other words, if the diaphragm is a flat plate without a pressure absorbing portion, even if the inner region of the diaphragm and the diaphragm are about to be displaced, the peripheral edge of the diaphragm is fixed to the case, so that the displacement of the diaphragm is inhibited. Although the detection accuracy is lowered, such inconvenience can be avoided in the present invention in which the stress absorbing portion is provided in the diaphragm.

Here, in the present invention, it is preferable that the stress absorbing portion is a curved portion formed in a circumferential shape.
In this invention of this structure, the manufacturing cost of an apparatus can be made low by making the shape of a stress absorption part simple.

The diaphragm and the diaphragm may be integrated by bonding, or the diaphragm and the diaphragm may be integrated in close contact in a vacuum state.
In the present invention in which the diaphragm and the diaphragm are integrated by bonding, in order to increase the closeness of the diaphragm and the diaphragm, it is possible to improve detection accuracy by bonding with an adhesive, and to measure It is also effective for pressures below the region.
On the other hand, in the configuration in which the diaphragm and the diaphragm are integrated in close contact in a vacuum state, it is not necessary to apply an adhesive between the diaphragm and the diaphragm. Therefore, it is not necessary to manage the film thickness of the adhesive, and the device can be manufactured easily.

1 is a cross-sectional view illustrating an overall configuration of a pressure detection device according to a first embodiment of the present invention. Sectional drawing which shows the principal part of the pressure detection apparatus concerning 2nd embodiment of this invention. Sectional drawing which shows the principal part of the pressure detection apparatus concerning the modification of this invention.

Embodiments of the present invention will be described with reference to the drawings. Here, in the description of each embodiment, the same components are denoted by the same reference numerals, and description thereof is omitted or simplified.
FIG. 1 is a cross-sectional view showing the overall configuration of the pressure detection device according to the first embodiment.
In FIG. 1, a pressure detection device includes a short cylindrical case 1 made of stainless steel, a detection element 2 provided in the case 1 for detecting pressure, a circuit board 3 connected to the detection element 2, The pressure sensor includes a stainless steel cover 4 that covers the circuit board 3. This pressure sensor is used in the food industry field, and is provided, for example, in a pipe of a food production plant.

The case 1 has an attachment hole 1A for attaching the detection element 2 to the center thereof, and a flange portion 1B on the end face side. One surface of the flange portion 1B is a pressure receiving surface 1C. The flange portion 1B of the case 1 is attached to an installation portion of a pipe (not shown) so that the measurement fluid is in contact with the pressure receiving surface 1C.
A concave portion 1D is formed continuously on the pressure receiving surface 1C of the case 1, and a tapered portion 1E is formed between the end of the concave portion 1D and the mounting hole 1A.
A step portion 1F is formed on the end surface of the case 1 opposite to the pressure receiving surface 1C.

The detection element 2 includes a thick substrate 20 attached to the attachment hole 1A of the case 1, a diaphragm 21 disposed opposite to one surface of the substrate 20, and the displacement of the diaphragm 21 provided on the diaphragm 21 and the substrate 20. A displacement detection unit 22 to detect, and a diaphragm 23 provided in close contact with the surface of the diaphragm 21 opposite to the surface facing the substrate 20 are provided.
The board | substrate 20 consists of ceramics and is formed in the column shape. The substrate 20 has an axis that coincides with the axis of the mounting hole 1A, and an outer peripheral surface thereof is separated from the inner peripheral surface of the mounting hole 1A by a predetermined distance.

The substrate 20 is attached to the case 1 with a holding member 24, a holding plate 25, and screws 26.
The holding member 24 is formed integrally with an engagement piece 24A sandwiched between the inner peripheral surface of the mounting hole 1A of the case 1 and the outer peripheral surface of the substrate 20 and the end of the engagement piece 24A. This is a member having a ring-shaped portion 24B covering the step portion 1F and the end surface of the substrate 20 and having a T-shaped cross section. A fixing member 27 is provided between the ring-shaped portion 24 </ b> B and the substrate 20. For the fixing member 27, brazing, welding, or the like can be adopted in addition to an adhesive or the like.
The holding plate 25 overlaps with the flat surface portion of the ring-shaped portion 24B, and is a disc whose outer peripheral edge coincides with the outer peripheral edge of the ring-shaped portion 24B. The holding plate 25 and the ring-shaped portion 24 </ b> B of the holding member 24 are fixed to the step portion 1 </ b> F of the case 1 with a screw 26.

The diaphragm 21 is made of ceramics and has a disk shape with a diameter of D1. The outer peripheral edge of the diaphragm 21 coincides with the outer peripheral edge of the substrate 20.
An annular glass member 28 is provided as an insulating member on the outer peripheral portion of the diaphragm 21 and the substrate 20.
Electrodes 22A and 22B constituting the displacement detector 22 are formed on the surfaces of the diaphragm 21 and the substrate 20 facing each other by printing or the like. Therefore, a capacitor is formed from the space S provided with these electrodes 22 </ b> A and 22 </ b> B and composed of the substrate 20, the diaphragm 21, and the glass member 28.

The electrode 22 </ b> A formed on one surface of the substrate 20 is electrically connected to the circuit substrate 3 through a through hole 20 </ b> A formed inside the substrate 20 and an electrode pin 29 erected on the other surface of the substrate 20. The electrode 22B formed on the diaphragm 21 is electrically connected to the circuit board 3 through the through hole 20B formed in the substrate 20 and the glass member 28 and the electrode pin 29 erected on the other surface of the substrate 20. That is, when the diaphragm 21 receives pressure on the side opposite to the substrate 20, the diaphragm 21 is displaced by this pressure, and the capacitance of the capacitor changes. This change in capacitance is sent as a signal to the circuit board 3 through the through holes 20A and 20B and the electrode pins 29.
A communication hole 20 </ b> C for communicating the space S composed of the diaphragm 21, the substrate 20, and the glass member 28 with the external space is formed in the substrate 20.

The diaphragm 23 includes a ring-shaped outer peripheral portion 23A disposed in the concave portion 1D of the case 1, a disc-shaped central portion 23B disposed to face the diaphragm 21, and a stress that connects the central portion 23B and the outer peripheral portion 23A. It is a thin disk-shaped member having the absorbing portion 23 </ b> C, and is disposed so as to be flush with the pressure receiving surface 1 </ b> C of the case 1. The material of the diaphragm 23 is preferably stainless steel (SUS316L), but it is also possible to adopt a highly corrosion-resistant material such as a cobalt nickel alloy other than stainless steel.
The outer peripheral portion 23A is fixed by welding or the like so that the outer edge thereof becomes dense with the end of the recess 1D so that no gap is formed between the outer periphery 23A and the end of the recess 1D. The central portion 23 </ b> B is integrated with the entire surface of the diaphragm 21 with an adhesive layer 230. Here, the adhesive layer 230 preferably uses a silicon-based adhesive.
The adhesive layer 230 is formed in a planar circle having a diameter of D2. The diameter D2 is substantially the same as the inner peripheral diameter of the glass member 28 or inside thereof, and is smaller than the diameter D1 of the diaphragm 21. In the region outside the adhesive layer 230, the diaphragm 21 and the diaphragm 23 are simply polymerized without being bonded and fixed.
The stress absorbing portion 23 </ b> C is a curved portion (a wavy portion) that protrudes toward the space K surrounded by the holding member 24, the case 1, the substrate 20, and the diaphragm 23. The protruding portion of the curved portion is separated from the tapered portion 1E. In other words, the tapered portion 1E is formed so as not to interfere with the stress absorbing portion 23C. The curved portion is continuously formed in an annular shape.

The circuit board 3 is electrically connected to a plurality of cables 31, and these cables 31 are collected inside a single tube 32 and led out of the cover 4. These cables 31 are connected to a control device (not shown), and pressure value data inside the pipe is output to the control device.
In addition to the cable 31, an atmosphere release tube 33 is disposed inside the tube 32, and the atmosphere release tube 33 communicates with the communication hole 20 </ b> C of the substrate 20 through a connection pipe 34 and a conduction pipe 35.
One end of the atmosphere release tube 33 is opened to the atmosphere, and the other end is connected to one end of the connection pipe 34 inside the cover 4. The connection pipe 34 is made of a flexible material, and the other end is connected to the conduction pipe 35. The conduction pipe 35 includes one end portion 35A connected to the connection pipe 34, a pipe body 35B formed integrally with the one end portion 35A, and a flange portion 35C connected to the pipe body 35B. The portion 35C is fixed in close contact with the substrate 20 via the O-ring 36. The internal space of the conduction pipe 35 is arranged so as to be linear with the communication hole 20C. The pipe main body 35 </ b> B penetrates the holding member 24 and the holding plate 25.

  The cover 4 is a bottomed cylindrical member having a cylindrical part 4A whose one end opening is joined to the case 1 by welding or the like, and a disk-shaped part 4B provided at the other end of the cylindrical part 4A. A cable gland 41 for accommodating the cable 31 is attached to the disc-like portion 4B. The cable gland 41 is tightly attached to the cover 4, whereby the inside of the cover 4 is sealed.

Next, a method for assembling the pressure detection device of the first embodiment will be described.
First, the outer peripheral portion 23A of the diaphragm 23 is joined to the concave portion 1D of the case 1 by welding or the like. Further, the substrate 20 on which the electrode 22A is formed and the diaphragm 21 on which the electrode 22B is formed are joined to each other with the glass member 28 interposed therebetween, and the substrate 20, the diaphragm 21 and the glass member 28 are inserted into the mounting hole 1A of the case 1. To do. The diaphragm 21 and the central portion 23B of the diaphragm 23 are joined to each other with an adhesive, and the substrate 20 is attached to the case 1 with a holding member 24, a holding plate 25, and screws 26. Then, the circuit board 3 is attached to face the board 20, the cable 31 is connected to the circuit board 3, and the conductive pipe 35, the connection pipe 34, and the air release tube 33 are connected to the board 20 to constitute a capacitor. The cover 4 is joined to the case 1 with the space S to be communicated with the atmosphere.

The case 1 of the pressure detection apparatus assembled in this way is attached to a pipe of an installation part (not shown) with a clamp. When the case 1 is tightened with the clamp, the stress generated in the flange portion 1B of the case 1 is transmitted to the outer peripheral portion 23A of the diaphragm 23 and tries to be transmitted from the outer peripheral portion 23A to the central portion 23B. The stress is absorbed by 23C.
When the fluid to be measured is introduced into the pressure detection device attached to the pipe, the diaphragm 23 receives pressure, and the diaphragm 23 is displaced together with the diaphragm 21. When the diaphragm 21 is displaced, the distance between the electrodes 22A and 22B constituting the displacement detector 22 changes, and this change is sent to the control device as a change in pressure value.

Therefore, in the first embodiment, the following operational effects can be achieved.
(1) A mounting hole 1A is formed inside the case 1 where the pressure receiving surface 1C is formed on one surface, a substrate 20 is fixed to the mounting hole 1A of the case 1, and a diaphragm 21 is disposed opposite to the substrate 20, A displacement detector 22 for detecting the displacement of the diaphragm 21 is provided on the diaphragm 21 and the substrate 20, and a diaphragm 23 is provided in close contact with the surface of the diaphragm 21 opposite to the surface facing the substrate 20. The outer peripheral portion 23 </ b> A of the 23 is fixed to the concave portion 1 </ b> D of the case 1, and the displacement is transmitted to the diaphragm 21 directly from the diaphragm 23. Therefore, since no liquid exists as the pressure transmission member, the thermal expansion / contraction of the liquid due to a temperature change is eliminated, and further, the labor for injecting the liquid can be omitted, and the manufacturing cost of the apparatus is reduced. In addition, since the diaphragm 23 is in close contact with the diaphragm 21 and the diaphragm 21 is opposed to the substrate 20, even if an overpressure exceeding the allowable overload is applied to the diaphragm 23 and the diaphragm 21, the substrate 20 is in contact and serves as a backup. Improved characteristics.

(2) The diaphragm 23 is disposed so as to be flush with the pressure-receiving surface 1C of the case 1, and the diaphragm 23 and the diaphragm 21 are in surface contact with each other. Less hygiene problems.
(3) The diaphragm 23 includes an outer peripheral portion 23A in contact with the case 1, a central portion 23B in contact with the diaphragm 21, and a stress absorbing portion 23C provided between them to absorb stress. Even when the outer peripheral portion 23A of the diaphragm 23 fixed to the case 1 is distorted together with the case 1 when the case 1 is clamped, the stress is absorbed by the stress absorbing portion 23C of the diaphragm 23. The case distortion is difficult to be transmitted to the diaphragm 21, and the change in the output when the clamp is tightened can be suppressed to prevent the detection accuracy from being lowered. Moreover, when the pressure is applied to the inner region partitioned by the stress absorbing portion 23C of the diaphragm 23 and the inner region and the diaphragm 21 in contact with the inner region are to be displaced, this displacement is not inhibited by the stress absorbing portion 23C. Therefore, it is possible to prevent a decrease in detection accuracy.

(4) Since the stress absorbing portion 23C is a curved portion formed in a circumferential shape, the stress absorbing portion 23C can be easily formed by forming the diaphragm 23 by press working or the like. Therefore, the manufacturing cost of the pressure detection device can be reduced.
(5) Since the taper portion 1E for preventing the interference with the stress absorbing portion 23C is formed on the substrate 20, the displacement of the diaphragm 23 is not hindered, and high detection accuracy can be maintained.
(6) Since the diaphragm 21 and the diaphragm 23 are integrated by the adhesive layer 230, the detection accuracy can be improved, and it is effective for a pressure lower than the measurement region. In particular, even if a negative pressure is applied, the diaphragm 23 is not separated from the diaphragm 21, so that a reduction in detection accuracy can be prevented. In addition, the diameter D2 of the adhesive layer 230 is formed smaller than the diameter D1 of the diaphragm 21, and in the region outside the adhesive layer 230, the diaphragm 21 and the diaphragm 23 are simply polymerized without being adhered, When the diaphragm 23 and the diaphragm 21 are displaced so as to bend around the central portion with the introduction, even if a difference in the extension in the plane direction occurs as the diaphragm 23 and the diaphragm 21 move toward the outer periphery, the adhesion Since the region outside the layer 230 is not bonded, the difference in extension can be absorbed to prevent a decrease in detection accuracy. In particular, when the non-adhesive portion of the diaphragm 23 with the diaphragm 21 is increased, the stress absorbing portion 23C is increased, and detection with higher accuracy is possible.

(7) Since the surface of the substrate 20 opposite to the surface on which the diaphragm 21 is provided is held in the case 1 by the holding member 24 and the holding plate 25, and these are attached to the case 1 by screws 26. The diaphragm 21 can be brought into surface contact with the diaphragm 23. For this reason, the surface of the diaphragm 23 and the pressure receiving surface 1C of the case 1 are likely to be flush with each other, and the measurement surface is easily made into a flash surface.
(8) The holding member 24 includes an engagement piece 24A that is sandwiched between the case 1 and the substrate 20, and a ring-shaped portion 24B that is integrally formed at the end of the engagement piece 24A. Therefore, the positioning of the diaphragm 23 having the outer peripheral portion 23A fixed to the case 1 and the diaphragm 21 provided on the end face side of the substrate 20 is accurately performed, and the detection accuracy is improved.

Next, a second embodiment of the present invention will be described with reference to FIG.
The second embodiment differs from the first embodiment in the structure for joining the diaphragm 21 and the diaphragm 23 and the structure for fixing the substrate 20 to the case 1, and the other configurations are the same as those in the first embodiment.
FIG. 2 is a cross-sectional view showing a main part of the second embodiment.
In FIG. 2, the pressure detection device of the second embodiment is a pressure sensor including a case 1, a detection element 2, a circuit board 3, and a cover 4 (see FIG. 1), as in the first embodiment.
The detection element 2 includes a substrate 20, a diaphragm 21, a displacement detection unit 22, and a diaphragm 23. In the second embodiment, the substrate 20 is fixed to the case 1 with a holding member 24. That is, airtight welding or electron beam welding is performed in a state in which the outer peripheral edge portion of the ring-shaped portion 24B of the holding member 24 is in contact with the step portion 1F of the case 1.
The space K surrounded by the case 1, the substrate 20, the diaphragm 23 and the holding member 24 is maintained at a high vacuum. As a result, there is no adhesive and the diaphragm 21 and the central portion 23B of the diaphragm 23 are integrated. The

Therefore, in the second embodiment, in addition to the same effects as (1) to (5) and (8) of the first embodiment, the following effects can be obtained.
(9) Since the diaphragm 21 and the diaphragm 23 are in close contact with each other in a vacuum state, it is not necessary to apply an adhesive between the diaphragm 21 and the diaphragm 23. Therefore, it is not necessary to manage the film thickness of the adhesive, and the device can be manufactured easily.

It should be noted that the present invention is not limited to the above-described embodiments, and modifications, improvements, and the like within the scope that can achieve the object of the present invention are included in the present invention.
For example, in each of the above-described embodiments, the holding member 24 is used to fix the portion of the substrate 20 where the diaphragm 21 is not provided to the case 1, but in the present invention, as shown in FIG. The engaging protrusion 1G from the inner peripheral surface of the step portion 1F toward the center of the case may be provided along the circumferential direction, and the fixing material 27 may be provided on the engaging protrusion 1G and the outer peripheral edge portion of the substrate 20. . In FIG. 3, as in the second embodiment, the space K is in a vacuum state, and the diaphragm 21 and the diaphragm 23 are integrated without using an adhesive. Further, illustration of the through holes 20A and 20B and the communication hole 20C is omitted.

Further, in each of the embodiments, the stress absorbing portion 23C is a curved portion formed in an annular shape. However, in the present invention, a plurality of curved portions may be provided along the circumferential direction, and the tip of the space S may be desired. The shape which protrudes in the opposite side to the space S may be sufficient.
The pressure detection device may be a differential pressure sensor that detects a differential pressure instead of a pressure sensor.
Furthermore, the pressure detection device of the present invention may be used in a chemical plant.

  The present invention can be used for pressure detection devices used in the food industry, chemical industry, and other fields.

  DESCRIPTION OF SYMBOLS 1 ... Case, 1A ... Mounting hole, 1C ... Pressure receiving surface, 2 ... Detection element, 3 ... Circuit board, 4 ... Cover, 20 ... Board | substrate, 21 ... Diaphragm, 22 ... Displacement detection part, 23 ... Separator, 23A ... Outer peripheral part , 23B ... central part, 23C ... stress absorbing part, 24 ... holding member, 230 ... adhesive layer

Claims (4)

A case in which a mounting hole is formed inside and a pressure receiving surface is formed on one surface; a substrate fixed to the mounting hole of the case; a diaphragm disposed to face one surface of the substrate; the diaphragm and the substrate; A displacement detector for detecting the displacement of the diaphragm, and a diaphragm provided in close contact with the surface of the diaphragm opposite to the surface facing the substrate and having a peripheral edge fixed to the case. ,
The diaphragm is disposed so as to be flush with the pressure-receiving surface of the case, and is a stress absorption part that absorbs stress in a region outside the region in contact with the diaphragm and in a region inside the region in contact with the case A pressure detection device comprising: The pressure detection device according to claim 1,
The pressure detecting device, wherein the stress absorbing portion is a curved portion formed in a circumferential shape. The pressure detection device according to claim 2,
The pressure detection device, wherein the diaphragm and the diaphragm are bonded and integrated. The pressure detection device according to claim 2,
The diaphragm and the diaphragm are integrated in close contact in a vacuum state.

Images