Pressure detection device and method for manufacturing the same

Abstract

To provide a pressure detector capable of inhibiting liquid from deterioration in quality due to elution of metal ions.SOLUTION: A pressure detector 100 comprises a pressure detection unit 10 and a flow passage unit 20. The flow passage unit 20 includes a contact part 22 arranged being in contact with the pressure detection unit 10. The contact part 22 includes: a protective film 22a arranged being in contact with a pressure detection surface, and blocking contact between the pressure detection surface and liquid; and a main body part 22b forming an opening 22c arranged at an end of a flow channel 21a. The protective film 22a and the main body part 22b are formed of thermoplastic fluorocarbon resin. The protective film 22a is arranged so as to close the opening 22c of the main body part 22b, and fused to the main body part 22b in an annular region extending circumferentially about an axis X.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a pressure detection device for detecting the pressure of a liquid flowing through a flow path, and a method for manufacturing the pressure detection device. [Background technology]

[0002] Conventionally, there is known a pressure detection device including a housing having a flow path through which a liquid such as a chemical solution is guided, and a sensor element that detects the pressure of the liquid transmitted to a pressure-sensitive part that comes into contact with the liquid guided to the flow path (see, for example, Patent Document 1). The pressure detection device disclosed in Patent Document 1 includes a pressure detection unit having a diaphragm that forms a pressure detection surface, and a flow path unit that forms a flow path and comes into contact with the pressure detection unit.

[0003] The pressure detection device disclosed in Patent Document 1 has a thin protective film disposed between a diaphragm and a flow path unit, and an O-ring disposed in a recessed groove provided on the surface of the flow path unit facing the pressure detection unit. This pressure detection device prevents liquid guided to the flow path from entering the pressure detection unit by an annular seal area formed by contact between the protective film and the O-ring. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2018-72106 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, when an O-ring made of rubber or the like is used as in the pressure detection device disclosed in Patent Document 1, there is a possibility that metal ions will be eluted into the chemical solution upon contact with the chemical solution, such as hydrofluoric acid, thereby degrading the quality of the chemical solution.

[0006] The present invention has been made in consideration of the above circumstances, and has an object to provide a pressure detection device that is capable of suppressing deterioration in the quality of liquid due to the elution of metal ions. [Means for solving the problem]

[0007] In order to solve the above problems, the present invention employs the following means. A pressure detection device according to one aspect of the present invention includes a pressure detection section having a pressure detection surface for detecting the pressure of a liquid, and a flow path section in which a flow path is formed that guides liquid to the pressure detection surface and extends along an axis, the flow path section having a contact section that is arranged in contact with the pressure detection section, the contact section being a thin-film-like insulating layer that is arranged in contact with the pressure detection surface and blocks contact between the pressure detection surface and the liquid. formed in protection film and a body portion forming an opening disposed at an end of the flow path, film The main body is made of a thermoplastic fluororesin, and the protective film is disposed so as to close the opening of the main body portion and is welded to the main body portion in an annular region extending in a circumferential direction around the axis line. The annular region is a region that is disposed on the outer circumferential side of the opening and on the inner circumferential side of the end of the protective film in a radial direction perpendicular to the axis. .

[0008] According to the pressure detection device of the present invention, the liquid is guided by the flow path portion having the flow path extending along the axis, and the pressure detection surface of the pressure detection portion is guided to detect the pressure of the liquid. film Since the contact between the pressure detection surface and the liquid is blocked by the protection film, the liquid is prevented from directly contacting the pressure detection surface. film is arranged so as to close an opening located at the end of the flow passage formed by the flow passage portion, and is welded to the main body portion of the contact portion in an annular region extending circumferentially around the axis.

[0009] protection film The body and the case are made of thermoplastic fluororesin, providing excellent protection. filmA welded portion is formed where the main body and the pressure sensing surface are fused together. This welded portion does not contain any other material into which metal ions can be eluted. Therefore, even if the liquid introduced to the pressure sensing surface enters the welded portion, metal ions will not be eluted, and deterioration of the quality of the liquid due to elution of metal ions can be suppressed.

[0010] In the pressure detection device according to one aspect of the present invention, the opening is formed in a cylindrical shape having a predetermined inner diameter extending along the axis, Marking diameter It is preferable that the position of the inner circumferential surface of the opening coincides with the position of the inner circumferential end of the annular region in the direction.

[0011] According to the pressure detection device having this configuration, the position of the inner circumferential surface of the opening coincides with the position of the inner circumferential end of the annular region, so that the pressure detection device can be protected. film There is no unwelded contact area between the body and the protective film Particles contained in the liquid do not accumulate in the non-welded contact area between the nozzle and the main body, and the accumulated particles do not flow out and degrade the essence of the liquid.

[0012] In the pressure detection device according to one aspect of the present invention, the thermoplastic fluororesin is preferably perfluoroalkoxy fluororesin (PFA). According to the pressure detection device of this configuration, film Furthermore, since the main body is made of perfluoroalkoxy fluororesin (PFA), it is possible to form a welded joint with stable and high adhesive strength.

[0013] In the pressure detection device according to an aspect of the present invention, a width of the annular region in a radial direction perpendicular to the axis (X) is preferably 0.5 mm or more and 1.5 mm or less. According to the pressure detection device having the above configuration, by setting the width of the annular region to 0.5 mm or more and 1.5 mm or less, it is possible to sufficiently increase the durability of the sealing function provided by the annular region.

[0014] A method for manufacturing a pressure detection device according to one aspect of the present invention is a method for manufacturing a pressure detection device including a pressure detection section having a pressure detection surface for detecting a pressure of a liquid, and a flow path section in which a flow path is formed that leads liquid to the pressure detection surface and extends along an axis, the flow path section having a contact section that is arranged in contact with the pressure detection section, the contact section being a thin-film-like insulating film that is arranged in contact with the pressure detection surface and blocks contact between the pressure detection surface and the liquid. formed in protection film and a body portion forming an opening disposed at an end of the flow path, film The main body is made of a thermoplastic fluororesin, and the protective member is disposed so as to close the opening of the main body. film and disposing the protective member along a circumferential direction around the axis. film The protective layer is irradiated with laser light. film and a welding step of forming an annular region where the main body portion and the welding portion are welded to each other. The annular region is a region that is disposed on the outer circumferential side of the opening and on the inner circumferential side of the end of the protective film in a radial direction perpendicular to the axis. do.

[0015] According to the method for manufacturing a pressure detection device according to one aspect of the present invention, film is disposed so as to close an opening disposed at an end of the flow passage formed by the flow passage portion, and is welded to the main body portion of the flow passage portion in an annular region extending in the circumferential direction about the axis.

[0016] protection film The body and the case are made of thermoplastic fluororesin, providing excellent protection. film A welded portion is formed where the main body and the pressure sensing surface are fused together. This welded portion does not contain any other material into which metal ions can be eluted. Therefore, even if the liquid introduced to the pressure sensing surface enters the welded portion, metal ions will not be eluted, and deterioration of the quality of the liquid due to elution of metal ions can be suppressed.

[0017] In a method for manufacturing a pressure detection device according to one aspect of the present invention, the opening is formed in a cylindrical shape having a predetermined inner diameter extending along the axis, Marking diameterThe protective member is disposed so that the position of the inner peripheral surface of the opening coincides with the position of the inner peripheral end of the annular region in the direction of the protective member. film and the main body are preferably welded together.

[0018] According to the manufacturing method of the pressure detection device having this configuration, the protection film is formed so that the position of the inner peripheral surface of the opening and the position of the inner peripheral end of the annular region are aligned. film Since the protective film and the main body are welded together, there is no area between the protective film and the main body where they are in contact without being welded, and therefore particles contained in the liquid do not accumulate in the area between the protective film and the main body where they are in contact without being welded, and the accumulated particles do not flow out and degrade the essence of the liquid.

[0019] In the method for manufacturing a pressure detection device according to one aspect of the present invention, the thermoplastic fluororesin is preferably a perfluoroalkoxy fluororesin (PFA). According to the manufacturing method for the pressure detection device having this configuration, since the protective portion and the main body portion are formed from perfluoroalkoxy fluororesin (PFA), it is possible to form a welded portion having a stable and high adhesive strength.

[0020] In the method for manufacturing a pressure detection device according to one aspect of the present invention, a width of the annular region in a radial direction perpendicular to the axis is preferably 0.5 mm or more and 1.5 mm or less. According to the method for manufacturing the pressure detection device having this configuration, by setting the width of the annular region to 0.5 mm or more and 1.5 mm or less, it is possible to sufficiently increase the durability of the sealing function provided by the annular region. Effect of the Invention

[0021] According to the present invention, it is possible to provide a pressure detection device capable of suppressing deterioration in the quality of liquid due to elution of metal ions. [Brief description of the drawings]

[0022] [Figure 1] 1 is a vertical cross-sectional view showing a pressure detection device according to an embodiment of the present invention; [Diagram 2] FIG. 2 is a partially enlarged view of the pressure detection device shown in FIG. [Diagram 3] FIG. 2 is an exploded view of the pressure detection device shown in FIG. [Figure 4] 4 is a plan view of the contact portion shown in FIG. 3 as viewed from above along the axis. [Diagram 5] FIG. 4 is a vertical sectional view of the contact portion shown in FIG. [Figure 6] 4 is a flowchart showing a method for manufacturing the pressure detection device according to one embodiment of the present invention. [Figure 7] 10 is a vertical cross-sectional view showing a state in which a protective film for the contact portion is disposed on a main body portion of the contact portion. FIG. [Figure 8] 10 is a vertical cross-sectional view showing a welding process for welding a main body of the contact portion and a protective film of the contact portion. FIG. [Figure 9] FIG. 11 is a vertical cross-sectional view showing a pressure detection device according to another embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] A pressure detection device 100 according to one embodiment of the present invention will be described below with reference to the drawings. Fig. 1 is a vertical cross-sectional view showing a pressure detection device according to one embodiment of the present invention. Fig. 2 is a partially enlarged view of the pressure detection device 100 shown in Fig. 1. Fig. 3 is an exploded view of the pressure detection device 100 shown in Fig. 1.

[0024] 1 and 2, the pressure detection device 100 of this embodiment includes a pressure detection unit 10 that detects the pressure of a liquid, and a flow path unit 20 having a flow path main body 21 in which a flow path 21a is formed. The flow path 21a is formed to guide the liquid to a diaphragm (pressure detection surface) 11a of the pressure detection unit 10 and to extend along an axis X.

[0025] The flow path 21a is connected to a flow path (not shown) branched from a pipe (not shown) through which a fluid flows. The liquid in this embodiment is a chemical liquid, a solvent, pure water, or the like used in a semiconductor manufacturing process by a semiconductor manufacturing device.

[0026] Next, the flow passage unit 20 included in the pressure detection device 100 of this embodiment will be described. The flow path unit 20 has a flow path main body 21, a contact portion 22, and a nut 23. As shown in Fig. 3, a recess 21b is formed in the flow path main body 21, and a female thread 21d is formed on the inner circumferential surface of the recess 21b.

[0027] 2, a bottom surface (accommodating portion) 21c of the recess 21b serves as an accommodating portion that accommodates the contact portion 22. An annular groove portion 21e extending circumferentially around the axis X is formed in the bottom surface 21c. A protrusion portion 22d of the contact portion 22 is inserted into the groove portion 21e. By inserting the protrusion portion 22d into the groove portion 21e, a seal area is formed that seals the liquid inside the flow path 21a so as not to leak to the pressure detection unit 10 side.

[0028] The flow path main body 21 has a flow path 21a formed therein that extends linearly along the axis X, and is made of a fluororesin material such as PTFE (polytetrafluoroethylene), PCTFE (polychlorotrifluoroethylene), or PFA (perfluoroalkoxy fluororesin).

[0029] As shown in Figs. 1 and 2, the contact portion 22 is a member arranged in a state of contact with the pressure sensor 11 described below. The contact portion 22 is arranged in an area facing a pressure detection surface consisting of the diaphragm 11a and the strain gauge 11b of the pressure sensor 11. The contact portion 22 has a protective film (protective portion) 22a and a main body portion 22b. Fig. 4 is a plan view of the contact portion 22 shown in Fig. 3 as viewed from above along the axis. Fig. 5 is a vertical cross-sectional view of the contact portion 22 shown in Fig. 3.

[0030] The protective film 22a is a thin-film member that is disposed in contact with the diaphragm 11a of the pressure sensor 11 and blocks contact between the diaphragm 11a and liquid. The protective film 22a is made of PFA (perfluoroalkoxy fluororesin), which is a thermoplastic fluororesin. As shown in FIG. 4, the protective film 22a is formed in a circular shape when viewed in a plan view along the axis X. The protective film 22a has a thickness of 0.05 mm or more and 2.5 mm or less, and preferably has a thickness of 0.05 mm or more and 0.1 mm or less.

[0031] The main body 22b is a member that is formed in an annular shape around the axis X and that forms the opening 22c that is disposed at the end of the flow path 21a. The main body 22b is formed of PFA (perfluoroalkoxy fluororesin), which is a thermoplastic fluororesin. The main body 22b is formed with an annular protrusion 22d that extends in the circumferential direction around the axis X. As shown in FIG. 5, the opening 22c is a cylindrical hole that extends along the axis X and has an inner diameter R1 centered on the axis X.

[0032] 4 and 5, the protective film 22a is disposed so as to close the opening 22c of the main body portion 22b. The protective film 22a is welded to the main body portion 22b in an annular region AR extending in the circumferential direction about the axis X. The welded portion WP shown in FIG. 2 indicates a portion where the protective film 22a and the main body portion 22b, which are made of the same material, are melted together and integrated. The welded portion WP is formed by irradiating a laser beam (e.g., a carbon dioxide laser beam) from above the protective film 22a.

[0033] 4 and 5, the annular region AR is a region in which an inner peripheral end has an inner diameter R1 and an outer peripheral end has an inner diameter R3 in a radial direction RD perpendicular to the axis X. As shown in Fig. 4, in the radial direction RD, the position of the inner peripheral surface of the opening 22c and the position of the inner peripheral end of the annular region AR coincide with each other. The inner diameter R2 is the inner diameter at the center position of the annular region AR (the position where the axis Y parallel to the axis X passes through), and satisfies the following formula (1). R2 = (R1 + R3) / 2 (1)

[0034] 4 and 5, the annular area AR has a width W1 in the radial direction RD. The width W1 is set to be any value within the range of the following formula (2). 0.5mm≦W1≦1.5mm (2) The range of formula (2) is a range that is set so as to be able to sufficiently increase the durability of the sealing function provided by the annular area AR, and to prevent the width of the annular area AR from being unnecessarily widened.

[0035] The nut 23 is a member that connects the flow path main body 21 to a flow path (not shown) branched off from a pipe (not shown) through which a fluid flows. The flow path 21a of the flow path main body 21 and the branched flow path are connected by fastening a female thread 23a formed on the inner peripheral surface of the nut 23 to a male thread (not shown) formed on the outer peripheral surface of the branched flow path.

[0036] Next, the pressure detection unit 10 included in the pressure detection device 100 of this embodiment will be described. The pressure detection unit 10 is a device that detects the pressure of the liquid transmitted to the diaphragm 11a.

[0037] 1 and 2, the pressure detection unit 10 includes a pressure sensor (pressure detection portion) 11 that detects the pressure of liquid, a sensor holder 12, a sensor board 14, a board holding member 15, and a housing 16. Each portion of the pressure detection unit 10 will be described below.

[0038] 2, the pressure sensor 11 includes a diaphragm 11a formed in a thin film, a strain gauge 11b which is a resistor attached to the diaphragm 11a, and a base portion 11c which holds the diaphragm 11a. The pressure sensor 11 is a strain gauge type pressure sensor which outputs a pressure signal according to the resistance value of the strain gauge 11b which changes according to the pressure transmitted to the diaphragm 11a. The diaphragm 11a and the strain gauge 11b form a pressure detection surface which detects the pressure of the liquid.

[0039] The diaphragm 11a has a lower surface in contact with the protective film 22a and an upper surface not in contact with the protective film 22a, and a strain gauge 11b is attached to the upper surface. The diaphragm 11a is made of a non-conductive material (e.g., sapphire, ceramics, etc.) that is resistant to corrosion and chemicals.

[0040] As shown in Fig. 3, the sensor holder 12 is a member formed in a cylindrical shape around the axis X, and has a male thread 12a formed on its outer circumferential surface. With the contact portion 22 accommodated in the bottom surface 21c of a recess 21b (see Fig. 3) formed in the flow path main body 21, the sensor holder 12 fastens the male thread 12a formed on its outer circumferential surface to a female thread 21d formed on the inner circumferential surface of the recess 21b, thereby fixing the positions of the pressure sensor 11 and the contact portion 22 in the direction of the axis X. As the male thread 12a and the female thread 21d are fastened together, the diaphragm 11a of the pressure sensor 11 and the protective film 22a of the contact portion 22 come into contact with each other with a predetermined pressing force being applied.

[0041] The sensor board 14 includes an amplifier circuit (not shown) that amplifies the pressure signal output by the pressure sensor 11, an interface circuit that transmits the pressure signal amplified by the amplifier circuit to a pressure signal line (not shown) of the cable 200 (see Figures 1 and 2), and a power supply circuit (not shown) that transmits a power supply voltage supplied from the outside via the cable 200 to the pressure sensor 11.

[0042] The substrate holding member 15 is a member that holds the sensor substrate 14 relative to the sensor holder 12. As shown in Fig. 2, the substrate holding member 15 is fastened to a fastening hole 13b formed in the upper surface of the sensor holder 12 by a fastening screw 19 with a spacer 18 sandwiched therebetween.

[0043] Next, a method for manufacturing the pressure detection device 100 of this embodiment will be described with reference to the drawings. Fig. 6 is a flow chart showing the method for manufacturing the pressure detection device 100 of this embodiment. Fig. 7 is a vertical cross-sectional view showing a state in which the protective film 22a of the contact portion 22 is disposed on the main body portion 22b of the contact portion 22. Fig. 8 is a vertical cross-sectional view showing a welding process for welding the main body portion 22b of the contact portion 22 and the protective film 22a of the contact portion 22 together.

[0044] In the arrangement process of step S101, the worker arranges the main body portion 22b on the welding jig 300, and arranges the protective film 22a so as to close the opening 22c of the main body portion 22b. The welding jig 300 has a groove portion 301 formed in an annular shape extending in the circumferential direction around the axis X. The worker fixes the main body portion 22b to the welding jig 300 by inserting the protrusion portion 22d formed on the main body portion 22b into the groove portion 301.

[0045] In the arrangement step, the worker arranges the protective film 22a on the upper surface of the main body portion 22b fixed to the welding jig 300 so that the central axis of the protective film 22a coincides with the axis X. The worker further arranges the glass plate 310 so that it is in contact with the entire upper surface of the protective film 22a.

[0046] The glass plate 310 is made of, for example, quartz glass, but may be made of other materials. Instead of the glass plate 310, a plate made of other material (e.g., germanium) that is transparent and has high transmittance may be used. In particular, by providing an anti-reflection film on both sides of the plate made of germanium, the transmission characteristics of the laser light can be improved.

[0047] The glass plate 310 is disposed so that when the contact surface between the main body 22b and the protective film 22a is heated by the laser light irradiated from above the glass plate 310, heat is removed from the upper surface of the protective film 22a in contact with the glass plate 310. By removing heat from the upper surface of the protective film 22a in contact with the glass plate 310, the upper surface of the protective film 22a is prevented from melting and forming an uneven shape. This makes it possible to maintain constant pressure transmission characteristics from the protective film 22a to the diaphragm 11a.

[0048] In the welding process of step S102, the protective film 22a is irradiated with laser light LB in the circumferential direction around the axis X to form an annular region AR where the protective film 22a and the main body portion 22b are welded together. As shown in Fig. 8, with the contact portion 22 fixed to the welding jig 300 and a glass plate 310 placed on the contact portion 22, a laser irradiation device 400 is installed at a position spaced apart from the axis X in the radial direction RD by an inner diameter R2 (a position where an axis Y parallel to the axis X passes through). Then, while maintaining the position spaced apart from the axis X in the radial direction RD by the inner diameter R2, the laser irradiation device 400 is moved in the circumferential direction around the axis X.

[0049] 4 around the axis X. By applying the laser beam LB, a welded portion WP is formed in the contact portion 22, where the protective film 22a and the main body portion 22b are melted together as PFA, which is a thermoplastic fluororesin that forms the protective film 22a and the main body portion 22b. The welded portion WP is formed only in the vicinity of the contact surface where the protective film 22a and the main body portion 22b contact each other, and is not formed on the surface where the protective film 22a and the glass plate 310 contact each other.

[0050] 8, in the welding process, the laser irradiation device 400 welds the protective film 22a and the main body portion 22b together such that the position of the inner circumferential surface of the opening 22c and the position of the inner circumferential end of the annular region AR in the radial direction RD coincide with each other. In addition, in the welding process, the laser irradiation device 400 welds the protective film 22a and the main body portion 22b together such that the width W1 of the annular region AR in the radial direction RD is 0.5 mm or more and 1.5 mm or less.

[0051] Here, the laser irradiation device 400 is, for example, a device that irradiates a carbon dioxide gas laser beam. The laser irradiation device 400 irradiates the laser beam LB in an output range of, for example, 7.5 W or more and 10.5 W or less. The laser irradiation device 400 also moves while irradiating the laser beam in the circumferential direction at a speed of 2 mm / sec or more and 11 mm / sec or less. The laser irradiation device 400 irradiates the position of the inner diameter R2 from the axis X with the laser beam LB for only one revolution.

[0052] In the assembly process of step S103, the worker assembles each part of the pressure detection device 100, including the contact part 22 in which the protective film 22a and the main body part 22b are welded, to the state shown in Fig. 1. Specifically, the worker attaches the contact part 22 to the flow path main body 21, and places the pressure sensor 11 on the contact part 22. After that, the worker fastens the male thread 12a of the sensor holder 12 to the female thread 21d of the flow path main body 21, so that the diaphragm 11a of the pressure sensor 11 comes into contact with the protective film 22a of the contact part 22.

[0053] The functions and effects of the pressure detection device 100 of the present embodiment described above will be described. According to the pressure detection device 100 of this embodiment, the pressure of the liquid is detected by guiding the liquid guided by the flow passage unit 20 having the flow passage 21a extending along the axis X to the diaphragm 11a which is the pressure detection surface of the pressure detection unit 10. The thin protective film 22a blocks contact between the diaphragm 11a and the liquid, preventing the liquid from directly contacting the diaphragm 11a. The protective film 22a is disposed so as to close the opening 22c disposed at the end of the flow passage 21a formed by the flow passage unit 20, and is welded to the main body 22b of the contact portion 22 in an annular region AR extending in the circumferential direction around the axis X.

[0054] Since the protective film 22a and the main body 22b are each made of PFA, a thermoplastic fluororesin, a welded portion WP is formed where the protective film 22a and the main body 22b are fused together. This welded portion WP does not contain other materials into which metal ions can be eluted. Therefore, even if the liquid introduced to the pressure detection surface enters the welded portion WP, metal ions will not be eluted, and deterioration of the quality of the liquid due to elution of metal ions can be suppressed.

[0055] Furthermore, according to the pressure detection device 100 of this embodiment, the position of the inner circumferential surface of the opening 22c coincides with the position of the inner circumferential end of the annular region AR, so there is no region between the protective film 22a and the main body 22b that is in contact without being welded. Therefore, particles contained in the liquid do not accumulate in the region between the protective film 22a and the main body 22b that is in contact without being welded, and the accumulated particles do not flow out and degrade the essence of the liquid.

[0056] Furthermore, according to the pressure detection device 100 of this embodiment, the protective film 22a and the main body portion 22b are made of perfluoroalkoxy fluororesin (PFA), so that the welded portion WP having a stable and high adhesive strength can be formed.

[0057] Furthermore, according to the pressure detection device of this embodiment, by setting the width W1 of the annular area AR to 0.5 mm or more and 1.5 mm or less, it is possible to sufficiently increase the durability of the sealing function provided by the annular area AR.

[0058] Other Embodiments In the above description, the pressure detection device 100 is described as having the flow path unit 20 including the flow path main body 21 and the contact portion 22 which is a separate member from the flow path main body 21 and is fixed to the flow path main body 21, but other configurations are also possible. For example, the pressure detection device 100A shown in FIG.

[0059] The pressure detection device 100A shown in Fig. 9 is a modified example of the pressure detection device 100 shown in Fig. 1, and is the same as the pressure detection device 100 shown in Fig. 1 except for the parts particularly described below. The pressure detection device 100A shown in Fig. 9 includes a flow path unit 20A in which a flow path 21a is formed. The flow path unit 20A has a flow path main body 21A, a contact portion 22A, and a nut 23. The flow path main body 21A and the contact portion 22A are integrally molded from PFA (perfluoroalkoxy fluororesin), which is a thermoplastic fluororesin.

[0060] According to the pressure detection device 100A shown in FIG. 9, the flow path main body 21A and the contact portion 22A are integrally formed from PFA, and therefore, compared to the case where these are formed as separate members and assembled, it is possible to reliably prevent liquid from leaking from the contact portion where the flow path main body 21 and the contact portion 22 come into contact. [Explanation of symbols]

[0061] 10 Pressure detection unit (pressure detection part) 11 Pressure Sensor 11a Diaphragm (pressure detection surface) 11b Strain Gauge 11c Base 12 Sensor holder 20, 20A Flow path unit (flow path section) 21, 21A Flow path body 21a Flow path 22,22A contact part 22a Protective film 22b Main body 22c opening 22d protrusion 23 Nut 100,100A pressure detector 300 Welding jig 301 Groove 310 Glass Plate 400 Laser irradiation device AR Annular Region RD radial direction WP welded part X axis

Claims

1. a pressure detection portion having a pressure detection surface for detecting a pressure of the liquid; a flow path portion in which a flow path is formed, the flow path extending along an axis and leading a liquid to the pressure detection surface; Equipped with the flow path portion has a contact portion arranged in a state of contact with the pressure detection portion, The contact portion is a protective film formed in a thin film shape that is disposed in contact with the pressure detection surface and blocks contact between the pressure detection surface and a liquid; a body portion defining an opening disposed at an end of the flow path; the protective film and the main body are formed of a thermoplastic fluororesin, the protective film is disposed so as to close the opening of the main body portion and is welded to the main body portion in an annular region extending in a circumferential direction around the axis, The pressure detection device, wherein the annular region is a region that is disposed radially outwardly of the opening and radially inwardly of the end of the protective film in a radial direction perpendicular to the axis.

2. The opening is formed in a cylindrical shape having a predetermined inner diameter extending along the axis, The pressure detection device according to claim 1 , wherein a position of an inner circumferential surface of the opening coincides with a position of an inner circumferential end of the annular region in the radial direction.

3. 3. The pressure detection device according to claim 1, wherein the thermoplastic fluororesin is a perfluoroalkoxy fluororesin.

4. 2. The pressure detection device according to claim 1, wherein a width of the annular region in a radial direction perpendicular to the axis is 0.5 mm or more and 1.5 mm or less.

5. a pressure detection portion having a pressure detection surface for detecting a pressure of the liquid; a flow path portion in which a flow path is formed, the flow path extending along an axis and leading a liquid to the pressure detection surface; A method for manufacturing a pressure detection device comprising: the flow path portion has a contact portion arranged in a state of contact with the pressure detection portion, The contact portion is a protective film formed in a thin film shape that is disposed in contact with the pressure detection surface and blocks contact between the pressure detection surface and a liquid; a body portion defining an opening disposed at an end of the flow path; the protective film and the main body are formed of a thermoplastic fluororesin, disposing the protective film so as to close the opening of the main body portion; a welding process of irradiating the protective film with laser light along a circumferential direction around the axis to form an annular region in which the protective film and the main body are welded together, A method for manufacturing a pressure detection device, wherein the annular region is a region that is positioned outer than the opening and inner than the end of the protective film in a radial direction perpendicular to the axis.

6. The opening is formed in a cylindrical shape having a predetermined inner diameter extending along the axis, The method for manufacturing a pressure detection device according to claim 5 , wherein the welding step includes welding the protective film and the main body portion together so that the position of the inner surface of the opening and the position of the inner end of the annular region coincide in the radial direction.

7. 7. The method for manufacturing a pressure detection device according to claim 5, wherein the thermoplastic fluororesin is a perfluoroalkoxy fluororesin.

8. 6. The method for manufacturing a pressure detection device according to claim 5, wherein the welding step includes welding the protective film and the main body so that a width of the annular region in a radial direction perpendicular to the axis is 0.5 mm or more and 1.5 mm or less.

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