JP2009085931A - Pressure sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pressure sensor allowing negative pressure measurement and usable under a high-temperature environment. <P>SOLUTION: This pressure sensor is provided with a thin film 20 deformable in response to pressure of a fluid, the first case 30 having a port 32 for introducing the fluid of a pressure measuring object, and arranged with the thin film 20 in a position receiving the pressure of the fluid introduced through the port 31, and a ceramic sensor 10 fixed adheredly onto a face opposite to the port 31 in the thin film 20, and for measuring the pressure of the fluid, and raw materials of the first case 30 and the thin film 20 are a polyether ether ketone. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a pressure sensor for measuring the pressure of a fluid such as liquid or gas.

  2. Description of the Related Art Conventionally, pressure sensors that are attached to various devices and measure the pressure of a fluid such as liquid or gas existing inside the device are known. For example, in the case of a pressure sensor used in a semiconductor manufacturing apparatus, it is used in an environment in contact with a chemical solution such as a strong acid. A conventional pressure sensor used in such an environment will be described with reference to FIG. FIG. 3 is a schematic cross-sectional view of a pressure sensor according to a conventional example.

  The pressure sensor 200 according to the conventional example has a thin film 220 that deforms according to the pressure of the fluid, and a port 231 into which the fluid whose pressure is to be measured is introduced, and receives the pressure of the fluid introduced through the port 231. It includes a case 230 in which the thin film 220 is disposed at a position, and a sensor 210 that is disposed so as to be in contact with the surface of the thin film 220 opposite to the port 231 and measures the pressure of the fluid. Further, an O-ring 240 is provided between the thin film 220 and the case 230 to seal a gap between them.

  Here, the thin film 220, the case 230, and the O-ring 240 are in an environment in contact with the chemical solution. For this reason, these members need to be resistant to chemicals. Usually, polytetrafluoroethylene (PTFE) is used as the material of the thin film 220 and the case 230, and fluororubber is used as the material of the O-ring 240. Or polytetrafluoroethylene is used.

  In addition, since some chemical solutions may slightly permeate the thin film 220, the sensor 210 is made of ceramic so as to be resistant to the chemical solution even a little.

  As described above, by adopting materials having resistance to the chemical solution as the materials of the various members, the pressure sensor can be suitably used even in an environment in contact with the chemical solution such as a strong acid.

  However, when it is necessary to measure the negative pressure, the thin film 220 is deformed so as to jump out to the port 231 side, so that a gap is formed between the thin film 220 and the sensor 210, and the pressure can be measured correctly. Can not. In this case, it is conceivable to bond the thin film 220 and the sensor 210. However, polytetrafluoroethylene used as a material of the thin film 220 has poor adhesion, and the thin film 220 and the ceramic sensor 210 are preferably used. There is no known adhesive that can be bonded. In addition, polytetrafluoroethylene has a drawback in that it cannot be used in a high-temperature environment because its strength changes remarkably at higher temperatures of 80 ° C. or higher.

  When a metal is used as a thin film material, there is a problem such as corrosivity, and when an elastomer is used, there is a problem that gas permeates, and any material cannot be used.

  An object of the present invention is to provide a pressure sensor that enables measurement of negative pressure and can be used even in a high temperature environment.

  The present invention employs the following means in order to solve the above problems.

That is, the pressure sensor of the present invention is
A thin film that deforms according to the pressure of the fluid;
A case having a port into which a fluid whose pressure is to be measured is introduced, and the thin film being disposed at a position where the pressure of the fluid introduced through the port is received;
A ceramic sensor that is fixed to the surface of the thin film opposite to the port by adhesion and measures the pressure of the fluid;
With
The material of the case and the thin film is polyether ether ketone.

  According to the present invention, by adopting polyether ether ketone (PEEK) as the material of the case and the thin film, polytetrafluoroethylene is adopted for the creep resistance, mechanical strength and heat resistance of these members. This can be improved compared to the case. Moreover, since the polyether ether ketone excellent in adhesiveness is adopted as the material of the thin film, the thin film and the ceramic sensor can be bonded with an adhesive. Thereby, even if it is a case where a negative pressure is measured, since a clearance gap does not arise between a thin film and a sensor, a negative pressure can also be measured appropriately.

  Here, the space between the case and the thin film may be sealed with a seal ring made of perfluoroelastomer.

  It is also preferable that the case and the thin film be fixed by welding.

  As described above, according to the present invention, the negative pressure can be measured and can be used even in a high temperature environment.

  The best mode for carrying out the present invention will be exemplarily described in detail below with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention only to those unless otherwise specified. .

Example 1
With reference to FIG. 1, the pressure sensor which concerns on Example 1 of this invention is demonstrated. FIG. 1 is a schematic cross-sectional view of a pressure sensor according to Embodiment 1 of the present invention.

<Configuration of pressure sensor>
The pressure sensor 100 according to the present embodiment is attached to various devices and is used to measure the pressure of a fluid such as liquid or gas existing inside the device. And the pressure sensor 100 which concerns on a present Example can be used suitably for a semiconductor manufacturing apparatus etc., for example, and can be used suitably also in the environment which contacts chemical | medical solutions, such as a strong acid.

  The pressure sensor 100 according to the present embodiment has a thin film 20 that deforms according to the pressure of the fluid, and a port 31 into which a fluid to be measured is introduced, and the pressure of the fluid introduced through the port 31. A first case 30 in which the thin film 20 is disposed at a receiving position is provided. In the present embodiment, the thin film 20 and the first case 30 both employ polyether ether ketone (PEEK) as the material.

  The pressure sensor 100 includes a ceramic sensor 10 that is disposed on the surface of the thin film 20 opposite to the port 31 and measures the pressure of the fluid. In this embodiment, the sensor 10 and the thin film 20 are fixed with an adhesive. In addition, since the adhesive itself has an influence on the measurement accuracy when the thickness of the adhesive is increased, the adhesive is used in this embodiment in consideration of adhesiveness and heat resistance. did. However, other appropriate adhesives may be used.

  Further, an O-ring 40 is provided between the thin film 20 and the case 30 as a seal ring that seals a gap between them. In this embodiment, Kalrez (registered trademark), which is a polymer material classified as perfluoroelastomer, is employed as the material of the O-ring 40.

  The pressure sensor 100 also includes a second case 50 that is fixed to the first case 30. In the present embodiment, a male screw 51 is formed on the outer periphery of the second case 50, and a female screw 33 is formed on the inner periphery of the first case 30, and the first case 30 and the second case 50 are fixed by screw fastening. It is configured as follows. A spacer 90 is provided between the front end portion 52 of the second case 50 and the end surface 11 on the side opposite to the port 31 in the sensor 10. Accordingly, the sensor 10 is fixed so as to be sandwiched between the inner wall surface 32 of the first case 30 and the spacer 90.

  Furthermore, the housing 70 of the sensor cable 60 connected to the sensor 10 and the cover 80 of the housing 70 are provided on the opposite side of the second case 50 from the placement portion of the sensor 10.

  Here, the sensor 10 measures the pressure of the fluid and uses a strain gauge. Since the pressure sensor itself using a strain gauge is a known technique, the details thereof will be omitted, and the principle of pressure measurement will be briefly described below.

  In a sensor using a strain gauge, a strain gauge is disposed on a diaphragm (in this embodiment, made of ceramic as described above), and when the pressure (stress) on the diaphragm changes, the diaphragm deforms accordingly, and the diaphragm This is based on the fact that the strain amount of the strain gauge formed above changes. In other words, since the electrical resistance changes as the strain amount of the strain gauge changes, a voltage is input to the strain gauge and the pressure on the diaphragm can be measured by measuring the output voltage. .

<Excellent points of this embodiment>
In this embodiment, polyether ether ketone having corrosion resistance and chemical resistance is adopted as the material of the thin film 20 and the first case 30, and Kalrez also having corrosion resistance and chemical resistance is used as the material of the O-ring 40. (Registered trademark) was adopted. Therefore, it can be suitably used even in an environment in contact with a chemical solution such as a strong acid. Moreover, although it may permeate | transmit the thin film 20 slightly depending on a chemical | medical solution, since the thing made from a ceramic is used as the sensor 10, the sensor 10 also has tolerance with respect to a chemical | medical solution.

  As described above, the pressure sensor 100 can be suitably used even in an environment in contact with a chemical solution such as a strong acid by adopting a material having resistance to the chemical solution as a material of various members.

Further, according to the pressure sensor 100 according to the present embodiment, the polyether ether ketone is adopted as the material of the first case 30 and the thin film 20, so that the creep resistance, mechanical strength, and heat resistance of these members are increased. This can be improved as compared with the case where polytetrafluoroethylene is employed. In addition, since Kalrez (registered trademark) excellent in heat resistance is adopted as a material of the O-ring 40, the pressure sensor 100 can be used in a high temperature environment.

  Furthermore, by employing polyether ether ketone having excellent adhesiveness as the material of the thin film 20, as described above, the thin film 20 and the ceramic sensor 10 can be bonded with an adhesive. Therefore, even when the negative pressure is measured, a gap does not occur between the thin film 20 and the sensor 10, so that the negative pressure can also be measured appropriately.

  As described above, the pressure sensor 100 according to the present embodiment can be used not only in an environment in contact with a chemical solution such as a strong acid but also in a negative pressure measurement and in a high temperature environment. .

(Example 2)
FIG. 2 shows a second embodiment of the present invention. In the first embodiment, an O-ring 40 is used to seal the gap between the thin film 20 and the case 30, whereas in this embodiment, a thin film is used to seal the gap. The structure which welds 20 and the case 30 is shown.

  Since other configurations and operations are the same as those in the first embodiment, the same components are denoted by the same reference numerals and description thereof is omitted.

  FIG. 2 is a schematic cross-sectional view of a pressure sensor according to Embodiment 2 of the present invention. In the pressure sensor 100a according to the present embodiment, the thin film 20 and the case 30 are fixed to each other by welding instead of the O-ring 40 with respect to the configuration of the pressure sensor 100 according to the first embodiment. In the figure, reference numeral 45 indicates a welded portion. Other configurations are the same as those of the first embodiment.

  Also in this example, the same effect as in the case of Example 1 is obtained, and in the case of this example, a seal structure using a perfluoroelastomer is adopted as compared with the case of Example 1. Therefore, the amount of permeated gas can be reduced, and the airtightness can be improved. Therefore, the influence of the permeating gas on the sensor 10 and the like can be further suppressed.

FIG. 1 is a schematic cross-sectional view of a pressure sensor according to Embodiment 1 of the present invention. FIG. 2 is a schematic cross-sectional view of a pressure sensor according to Embodiment 2 of the present invention. FIG. 3 is a schematic cross-sectional view of a pressure sensor according to a conventional example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Sensor 11 End surface 20 Thin film 30 1st case 31 Port 32 Inner wall surface 33 Female thread 40 O-ring 50 2nd case 51 Male screw 52 Tip part 60 Sensor cable 70 Housing 80 Cover 90 Spacer 100 Pressure sensor 100a Pressure sensor

Claims (3)

A thin film that deforms according to the pressure of the fluid;
A case having a port into which a fluid whose pressure is to be measured is introduced, and the thin film being disposed at a position where the pressure of the fluid introduced through the port is received;
A ceramic sensor that is fixed to the surface of the thin film opposite to the port by adhesion and measures the pressure of the fluid;
With
A pressure sensor characterized in that the material of the case and the thin film is polyether ether ketone.   The pressure sensor according to claim 1, wherein a space between the case and the thin film is sealed with a seal ring made of perfluoroelastomer.   The pressure sensor according to claim 1, wherein the case and the thin film are fixed by welding.

Images