Method for inspecting pressure sensors, method for manufacturing vacuum gauges, and pressure sensors

Abstract

To inspect characteristics of a pressure sensor that does not have joints.SOLUTION: A first cylindrical member 21A that forms an inflow space R2 of a pressure sensor 20 that converts, into an electric signal, a pressure difference between a reference vacuum room R1 and the inflow space R2 into which gas G in a measurement object space flows, and piping 102 for inspection are connected together via a seal member 101. Thereafter, vacuuming or pressuring is applied to the inflow space R2 via the piping 102 for inspection, and characteristic of the pressure sensor 20 is inspected. The first cylindrical member 21A and the piping 102 for inspection are connected together by a connecting member 110 that comprises, an insertion part 111A that is inserted into a recess 29 provided to an outside face of the pressure sensor 20 and an engaging part 112A that engages with the piping 102 for inspection.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a pressure sensor inspection method, a vacuum gauge manufacturing method, and a pressure sensor. Background Art

[0002] A pressure sensor used in a vacuum gauge is inspected after being manufactured. Such inspections include not only a leak inspection for inspecting the airtightness of a reference vacuum chamber in the pressure sensor (Patent Document 1), but also an inspection of characteristics of the pressure sensor (for example, the relationship between the pressure value of gas in a measurement target space introduced into the pressure sensor and the voltage value of an electrical signal output by the pressure sensor at that pressure value). Prior Art Literature Patent Literature

[0003] Patent Document 1 Japanese Unexamined Patent Publication No. 2022-78546 Summary of the Invention Problems to be Solved by the Invention

[0004] Here, a conventional pressure sensor as described in Patent Document 1 is actually configured to include a joint for a vacuum gauge, although this is not explicitly stated in Patent Document 1. Such a pressure sensor with a joint has the disadvantage that the type of vacuum gauge to which the pressure sensor can be applied is determined. For example, the connection destination of the vacuum gauge is determined by the size of the joint and the connection method of the joint. For example, when the vacuum gauge is a non-heating type that does not perform self-heating, the pressure sensor does not have a flange for attaching a heater for self-heating, and thus the pressure sensor cannot be used in a vacuum gauge that performs self-heating.

[0005] Therefore, the inventors of this application conceived of separating the pressure sensor and the tubular member including the fitting, allowing for the selection of tubular members of different shapes depending on the application of the vacuum gauge. This eliminates the need to prepare a considerable number of pressure sensors for all types of vacuum gauges, thereby reducing the amount of pressure sensors that need to be kept in stock.

[0006] However, if the pressure sensor and the tubular member including the joint are separate components, it becomes difficult to inspect the characteristics of the sensor element. This is because conventional inspections of the characteristics require the presence of the joint, as a predetermined device is connected to the joint to perform vacuuming, etc.

[0007] The present invention aims to perform characteristic testing of a pressure sensor without joints. [Means for solving the problem]

[0008] To solve the above problems, the welding method according to the present invention comprises a first step of connecting a cylindrical portion forming the inlet space of a pressure sensor that converts the pressure difference between the reference vacuum chamber and the inlet space into an electrical signal, via a sealing member, and an inspection pipe, after the first step, vacuuming or applying pressure to the inlet space via the inspection pipe to inspect the characteristics of the pressure sensor, wherein the cylindrical portion is configured to have one end formed as a joint for a vacuum gauge on which the pressure sensor is mounted, and the other end of a tubular member that introduces the gas flowing in from the one end to the other end is joined, and in the first step, the cylindrical portion and the inspection pipe are connected by a connecting member having an insertion portion that is inserted into a recess provided on the outer surface of the pressure sensor and an engagement portion that engages with the inspection pipe.

[0009] As an example, the housing of the pressure sensor comprises two members joined together, sandwiching the peripheral edge of the sensor support portion that supports the sensor element. One of the two members includes the cylindrical portion, and the recess has a bottom surface that includes the joint between the two members.

[0010] As an example, the inspection piping has a flange protruding from the upper end when the pressure sensor side is facing upward, the sealing member is sandwiched between the cylindrical portion and the flange, the insertion portion engages with the inner wall surface of the recess, the engagement portion engages with the lower surface of the flange, and the connecting member clamps the pressure sensor and the inspection piping with the insertion portion and the engagement portion.

[0011] As an example, the inspection pipe comprises a flange protruding from the upper end when the pressure sensor side is oriented upward, and a cylindrical portion extending upward from the peripheral edge of the flange and surrounding the cylindrical portion of the pressure sensor. The connecting member comprises an annular pressing member that presses the sealing member positioned between the cylindrical portion of the inspection pipe and the cylindrical portion of the pressure sensor, an insertion portion, an engaging portion that engages with the cylindrical portion of the inspection pipe through a through hole penetrating the cylindrical portion of the inspection pipe, and a restricting portion located between the insertion portion and the engaging portion that restricts the upward movement of the pressing member.

[0012] As an example, the inspection piping comprises a flange protruding from the upper end when the pressure sensor side is oriented upward, and a cylindrical portion extending upward from the peripheral edge of the flange and surrounding the cylindrical portion of the pressure sensor. The cylindrical portion of the inspection piping has a height that covers the lower portion of the recess, the sealing member is positioned in the lower portion of the recess, the insertion portion is inserted into the upper portion of the recess, the engaging portion engages with the lower surface of the flange, and the connecting member clamps the pressure sensor and the inspection piping via the sealing member using the insertion portion and the engaging portion.

[0013] A method for manufacturing a vacuum gauge according to the present invention is a method for manufacturing a vacuum gauge that includes a method for inspecting the pressure sensor, comprising: a third step of joining the tubular member to the cylindrical portion of the pressure sensor; and a fourth step of reflecting the inspection result from the second step in a control unit mounted on the vacuum gauge together with the pressure sensor.

[0014] The residual pressure sensor according to the present invention is a pressure sensor that converts the pressure difference between the reference vacuum chamber and the inflow space into an electrical signal, comprising a reference vacuum chamber and an inflow space into which gas from a space to be measured flows, and includes a sensor element that converts the pressure difference into an electrical signal, a sensor support portion that supports the sensor element, and a housing having a cylindrical portion that forms the inflow space, with one end formed as a joint for a vacuum gauge on which the pressure sensor is mounted, and the other end of a tubular member that introduces the gas flowing in from the one end to the other end being joined, wherein the housing comprises two members joined on either side of the peripheral edge of the sensor support portion, one of the two members including the cylindrical portion, and a recess is formed on the outer surface of the housing with the surface including the joint of the two members as the bottom surface. [Effects of the Invention]

[0015] According to the present invention, the characteristics of a pressure sensor without joints are tested. [Brief explanation of the drawing]

[0016] [Figure 1] Figure 1 is a schematic cross-sectional view of a vacuum gauge equipped with a pressure sensor according to an embodiment of the present invention. [Figure 2] Figure 2 is an exploded perspective view of a portion of the vacuum gauge shown in Figure 1. [Figure 3] Figure 3 is a flowchart of the manufacturing method for a vacuum gauge. [Figure 4] Figure 4 is a schematic cross-sectional view showing the connection between the pressure sensor and the inspection piping. [Figure 5] Figure 5 is a schematic cross-sectional view showing the connection between the pressure sensor and the inspection piping. [Figure 6] Figure 6 is a schematic cross-sectional view showing the connection between the pressure sensor and the inspection piping. [Modes for carrying out the invention]

[0017] Hereinafter, embodiments of the present invention will be described with reference to the drawings. First, a schematic configuration of a pressure sensor 20 and a vacuum gauge 10 will be described, then an inspection method for the pressure sensor 20 and a method for manufacturing the vacuum gauge 10 including this inspection method will be described. It should be noted that the vertical directions in the present specification are for convenience, and do not need to match the actual vertical orientation. In other words, "upper" does not need to be on the ceiling or air side, and "lower" does not need to be on the ground side.

[0018] As shown in FIG. 1 and FIG. 2, the vacuum gauge 10 includes a pressure sensor 20 that converts the pressure of a gas G in a measurement target space into an electric signal, a heater 30 that heats the pressure sensor 20, a bracket 40 that surrounds the pressure sensor 20, and a hollow tubular member 50 that introduces the gas G into the pressure sensor 20. The gas G is, for example, residual gas after evacuation of the space in a vacuum chamber serving as the measurement target space, or a process gas generated in the space inside the vacuum chamber.

[0019] As shown in FIG. 1, the vacuum gauge 10 includes a control device 70 that controls the pressure sensor 20 and the heater 30, and a plurality of wires H1 and H2 that electrically connect the pressure sensor 20 or the heater 30 to the control device 70. The vacuum gauge 10 also includes a baffle 60 described later. The control device 70 is configured to include a processing circuit such as a computer, takes out the electric signal converted by the pressure sensor 20 via the wire H1, and outputs the pressure of the gas G as the degree of vacuum of the measurement target space to the outside of the vacuum gauge 10 based on the taken-out electric signal.

[0020] The pressure sensor 20 includes a housing 21, a sensor element 22, a sensor support 23, and a plurality of (three in this example) conductive pins 24.

[0021] The housing 21 accommodates the sensor element 22 and the sensor support 23 that supports the sensor element 22. The housing 21 includes a cylindrical first tubular member 21A, a cylindrical second tubular member 21B joined to the upper end of the first tubular member 21A, and a disc-shaped lid member 21C that covers the upper end opening of the second tubular member 21B.

[0022] The first cylindrical member 21A and the second cylindrical member 21B are joined together, sandwiching the outer periphery of the sensor support portion 23. As a result, the sensor support portion 23 is supported and housed in the housing 21 with its outer periphery sandwiched between the first cylindrical member 21A and the second cylindrical member 21B. In Figure 1, the first cylindrical member 21A and the second cylindrical member 21B may be joined so that their entirety sandwiches the outer periphery of the sensor support portion 23, or they may be joined so that only a portion of them sandwiches the outer periphery of the sensor support portion 23. In the latter case, a portion is provided where the first cylindrical member 21A and the second cylindrical member 21B are directly joined.

[0023] The sensor support portion 23 comprises a thin plate (support diaphragm) including the outer peripheral edge, and a pair of upper and lower bases that sandwich the central part of the thin plate from above and below. The sensor element 22 is fixed to the upper surface of the bases, thereby supporting the sensor element 22 with the sensor support portion 23.

[0024] On the cylindrical outer surface of the housing 21 (the surface facing in a direction perpendicular to the vertical direction), a groove-shaped recess 29 is formed around the joint between the first cylindrical member 21A and the second cylindrical member 21B, and in its vicinity. The recess opens in a direction perpendicular to the vertical direction. The joint is located within the bottom surface of the recess 29 (the most recessed surface of the recess 29). This recess 29 is used for inspecting the pressure sensor 20, which will be described later.

[0025] The space inside the housing 21 is divided by the sensor element 22 and the sensor support part 23 into a reference vacuum chamber R1, which contains a reference vacuum level, and an inflow space R2 through which gas G flows in via the tubular member 50. A through hole 23A is provided in the center of the sensor support part 23 for introducing gas G into the sensor element 22. A baffle 60 is positioned below the through hole 23A and within the inflow space R2 to prevent gas G from flowing linearly into the through hole 23A (in other words, preventing gas G from directly hitting the diaphragm of the sensor element 22, which will be described later). The baffle 60 is attached to the tubular member 50.

[0026] The tubular member 50 comprises a cylindrical portion 51 and annular plate-shaped flanges 52 and 53 that protrude outward from the cylindrical portion 51. A heater 30 is fixed to flange 52, and a bracket 40 is fixed to flange 53. The lower end (one end) 54 of the tubular member 50 is formed as a joint for the vacuum gauge 10 on which the pressure sensor 20 is mounted, and is connected directly or indirectly via piping to the device that forms the space to be measured. The upper end (the other end) 55 of the tubular member 50 is joined to the lower end of the first cylindrical member 21A, which is a cylindrical portion that forms the inflow space R2, by welding or the like. The upper end 55 is the upper part of the cylindrical portion 51 and is a large-diameter portion that matches the size of the first cylindrical member 21A. The portion of the cylindrical portion 51 other than the upper end 55 is a small-diameter cylindrical portion that extends downward from the large-diameter portion to the lower end 54. The tubular member 50 introduces the gas G from the space to be measured, which flows in from its lower end (one end) 54, i.e., the joint, to its upper end (other end) 55, and then introduces it into the inflow space R2 formed by the first cylindrical member 21A. The upper part of the tubular member 50 has a sufficiently large internal space so that a baffle 60 can be placed there.

[0027] The sensor element 22 comprises a volume chamber into which the vacuum of a reference vacuum chamber R1 is introduced, a diaphragm facing the volume chamber and deforming according to the pressure difference between the vacuum introduced into the volume chamber and the gas in the space to be measured, i.e., the pressure difference between the reference vacuum chamber R1 and the inflow space R2, and a pair of counter electrodes provided in the volume chamber, the distance between which changes due to the deformation of the diaphragm. The sensor element 22 outputs the change in capacitance between the counter electrodes as an electrical signal, thereby converting the pressure difference between the reference vacuum chamber R1 and the inflow space R2 into an electrical signal and outputting it. This pressure difference indicates the pressure of the gas G in the space to be measured (vacuum of the space to be measured) with the vacuum of the reference vacuum chamber R1 as the reference. The sensor element 22 may also be of a type that converts the deformation of the diaphragm into an electrical signal using a piezoelectric element.

[0028] The electrical signal converted by the sensor element 22 is output to the control device 70 via a plurality of conductive pins 24 and wiring H1, and is used by the control device 70 to derive the pressure (vacuum level) of the gas G in the space to be measured. The plurality of conductive pins 24 each pass through a plurality of through holes provided in the lid member 21C of the housing 21 and are fixed to the lid member 21C by hermetic seals. Each conductive pin 24 may be fixed to the lid member 21C by hermetic seals while surrounded by a cylindrical shield. The number of conductive pins 24 is three here, but there may be other numbers. The conductive pins 24 may be connected to the sensor element 22 via contact springs or the like.

[0029] As shown in Figures 1 and 2, the heater 30 is cylindrical (internal structure etc. are omitted in Figure 1) and has a fixing portion 31 that protrudes inward from its inner surface. The heater 30 is fixed to the tubular member 50 by fixing the fixing portion 31 to the flange 52 of the tubular member 50. The heater 30 is driven by the control device 70 via wiring H2 to generate heat and heat the pressure sensor 20. This heating suppresses the deposition of substances contained in the gas G introduced into the housing 21 of the pressure sensor 20 on the diaphragm of the sensor element 22.

[0030] The bracket 40 supports the control device 70 while being fixed to the flange 53 of the tubular member 50. The bracket 40 comprises a polygonal cylindrical portion 41 with a hexagonal cross-section, and a protruding portion 42 that extends inward, i.e., toward the pressure sensor 20, from the lower end of the cylindrical portion 41. A through hole 43 is formed in the center of the protruding portion 42 through which the tubular member 50 passes. The bracket is fixed to the tubular member 50 by welding the protruding portion 42 and the flange 53.

[0031] Here, the manufacturing method of the vacuum gauge 10 and the inspection method of the pressure sensor 20 contained therein will be explained with reference to Figure 3.

[0032] First, the pressure sensor 20 is manufactured (step S1). Then, the pressure sensor 20 is inspected (step S2). This inspection includes a leak test (e.g., a helium leak test by immersion) to check the airtightness of the reference vacuum chamber R1 of the pressure sensor 20. Furthermore, this inspection also includes testing the characteristics of the pressure sensor 20.

[0033] In the inspection of the above characteristics, as shown in Figure 4, the inspection pipe 102 is connected to the lower end of the housing 21 of the pressure sensor 20 via a sealing member 101 made of an O-ring. The inspection pipe 102 comprises a cylindrical body 102A that forms an internal space R3, and an annular flange 102B that protrudes outward from the upper end of the body 102A and forms a joint for connection to the housing 21. An annular recess 102BA is formed on the upper surface of the flange 102B where the sealing member 101 is placed. The lower end of the inspection pipe 102 opposite to the pressure sensor 20 side is connected to a device capable of vacuuming and / or applying pressure, such as a vacuum pump.

[0034] The housing 21 of the pressure sensor 20 and the inspection pipe 102 are clamped by a plurality of arc-shaped connecting members 110 when viewed from above. The connecting member 110 comprises a first member 111 having an insertion portion 111A that is inserted into a recess 29 of the housing 21 and engages with the inner wall surface of the recess 29, and a second member 112 having an engagement portion 112A that fits under the flange 102B of the inspection pipe 102 and engages with the lower surface of the flange 102B. The connecting member 110 also includes a bolt 113 that passes through a through hole in the second member 112 and screws into the first member 111. With this configuration, by rotating the bolt 113, the housing 21 and the inspection pipe 102 are clamped by the insertion portion 111A and the engagement portion 112A. This clamp causes the sealing member 101 to be sandwiched between the housing 21 and the inspection pipe 102, creating an airtight connection between the inlet space R2 of the pressure sensor 20 and the internal space R3 of the inspection pipe 102.

[0035] With the clamping mechanism 110 in place, the pressure of the gas introduced into the pressure sensor 20 is controlled by vacuuming and / or applying pressure via the inspection piping 102, while the electrical signal output from the conductive pin 24 is measured using a predetermined measuring instrument. Based on the measurement results and the pressure at that time, the characteristics of the pressure sensor 20 are derived. These characteristics are, for example, the relationship between the pressure value of the gas introduced into the pressure sensor 20 and the voltage value of the electrical signal output by the pressure sensor 20 at that pressure. Conventional methods can be used for the measurement and derivation of the characteristics. The content of the characteristics and the measurement method are arbitrary and not limited to those described above.

[0036] Subsequently, as shown in Figure 3, the pressure sensor 20 and the tubular member 50 to which the baffle 60 is attached are welded together (step S3), and the heater 30 and bracket 40 are fixed to the tubular member 50 by welding (step S4). Then, the control device 70 is attached to the bracket 40 (step S5). At this time, the control device 70 and the pressure sensor 20 are connected by wiring H1, and the control device 70 and the heater 30 are connected by wiring H2. At any time, the control device 70 stores the formula or table representing the above characteristics in its memory. As a result, the control device 70 reflects the inspection results of the above inspection. The control device 70 is configured to derive the pressure of the gas G in the space to be measured based on the voltage value of the electrical signal from the pressure sensor 20 and the formula or table stored in memory, and output it externally. As a result, the pressure (vacuum level) of the gas G can be derived using an algorithm that reflects the characteristics of the pressure sensor 20.

[0037] After that, the vacuum gauge 10 is completed after undergoing optional additional processes such as operational checks (step S6).

[0038] In the above embodiment, the tubular member 50, which is conventionally manufactured integrally with the pressure sensor 20 as part of the pressure sensor 20, is made separate from the pressure sensor 20 and joined to the pressure sensor 20 after inspection. This allows for the manufacture of pressure sensors 20 that can be used in various types of vacuum gauges, stockpiling them, and manufacturing vacuum gauges by joining different tubular members to the pressure sensor 20 according to the specifications of the vacuum gauge to be manufactured. For example, a tubular member having a fitting of the shape required by the vacuum gauge can be joined to the pressure sensor 20. Also, if the vacuum gauge is a non-heated type that does not require a heater 30, a tubular member that does not require a flange 52 can be joined to the pressure sensor 20. If the vacuum gauge does not require a baffle 60, a smaller tubular member than the tubular member 50 can be used because it does not require space to accommodate the baffle 60. In this way, it is not necessary to stock pressure sensors for all vacuum gauges, the number of pressure sensors in stock can be reduced, and inventory management becomes easier. Furthermore, since pressure sensors without connectors can be stored in a compact form, the space required for inventory management is also reduced.

[0039] The characteristics of the pressure sensor 20 cannot be inspected in the same way as in the conventional method because the pressure sensor 20 does not have a joint. Therefore, in this embodiment, during characteristic inspection, a connecting member 110 is used to connect the first cylindrical member 21A, which is the cylindrical part forming the inlet space R2 of the pressure sensor 20, and the inspection pipe 102 via a sealing member 101. The connecting member 110 has an insertion part 111A that is inserted into a recess 29 provided on the outer surface of the pressure sensor 20 and an engagement part 112A that engages with the inspection pipe 102. This makes it possible to inspect the characteristics of the pressure sensor 20, which does not have a joint.

[0040] A standard O-ring can also be used as the sealing member 101.

[0041] Since the bottom surface of the recess 29 is the surface that includes the joint between the first cylindrical member 21A and the second cylindrical member 21B that sandwich the sensor support portion 23, the diameter of the sensor support portion 23 (more specifically, the diameter of the portion of the sensor support portion 23 not sandwiched by the first cylindrical member 21A and the second cylindrical member 21B) becomes smaller than the maximum inner diameter of the inflow space R2, thereby improving the sensor characteristics of the sensor element 22, more specifically, improving pressure resistance and reducing temperature hysteresis. Furthermore, with the above configuration, the inner diameter of the reference vacuum chamber R1 can be reduced, and the volume of the reference vacuum chamber R1 can be reduced. This reduces the time required for the above-mentioned leak test and vacuuming. As shown in Figure 4, it is preferable that the outer shape (contour) of the pair of bases 23C and 23D that sandwich the thin plate 23B of the sensor support portion 23 when viewed from above match the outer shape of the sensor element 22 when viewed from above. Conventionally, the outer dimensions of the bases 23C and 23D were larger. By making the outer dimensions the same, the diameter of the sensor support portion 23 can be made smaller than before, which allows the pressure sensor 20 to be made smaller and the volume of the reference vacuum chamber R1 to be reduced. Consequently, this also shortens the time required for the above-mentioned leak test and vacuuming.

[0042] By providing the recess 29 while increasing the maximum inner diameter of the inflow space R2, the gas flow path that bypasses the baffle 60 can be lengthened, improving the sediment trapping efficiency.

[0043] Since the pressure sensor 20 does not have a joint, the pressure sensor 20 is compact, the temperature gradient distribution within the sensor itself can be reduced, and the influence of the temperature characteristics of the pressure sensor 20 during characteristic testing can be reduced.

[0044] To measure the temperature of the side surface of the pressure sensor 20 and to stabilize its characteristics by maintaining a constant sensor temperature, a heater may be wrapped around the side surface of the pressure sensor 20 during the above characteristic test to heat the pressure sensor 20 to a constant temperature.

[0045] The diameter of the conductive pin 24 can be increased to improve its rigidity. This prevents pin bending during inspection and allows for a structure that does not require the connection of cables or other components.

[0046] The clamp provided by the connecting member 110 as described above allows for easy and airtight connection between the inspection pipe 102 and the pressure sensor 20. The shape of the connecting member 110 is arbitrary. The connecting member 110 may be a donut-shaped member when viewed from above. The connecting member 110 may also be a "slotted" type, as shown in Figure 6, in which a groove is formed between the insertion portion 111A and the engaging portion 112A, and the distance between them is fixed.

[0047] The shape of the inspection piping is arbitrary, and the method of connecting the inspection piping to the pressure sensor 20 is also arbitrary.

[0048] As shown in Figure 5, an inspection pipe 202 may be used. The inspection pipe 202 comprises a cylindrical body 202A that forms an internal space R3, and an annular flange 202B that protrudes outward from the upper end of the body 202A. The inspection pipe 202 includes a cylindrical portion 202C that extends upward from the peripheral edge of the flange 202B and surrounds the first cylindrical member 21A of the pressure sensor 20.

[0049] The inspection pipe 202 and the pressure sensor 20 are connected by a connecting member 210. The connecting member 210 includes an annular (in this case, particularly cylindrical) retaining member 211 that holds down a sealing member 101 positioned between the cylindrical portion 202C of the inspection pipe 202 and the first cylindrical portion 21A of the pressure sensor 20. The connecting member 210 further includes a plurality of rod-shaped restricting members 212, such as cylinders. Each restricting member 212 includes an insertion portion 212A that is inserted into the recess 29 and engages with the inner wall of the recess 29, and an engagement portion 212B that engages with the cylindrical portion 202C through a through hole 202CA formed in the cylindrical portion 202C. Each restricting member 212 also includes a restricting portion 212C located between the insertion portion 212A and the engagement portion 212B, which restricts the upward movement of the retaining member 211. The number of restricting members 212 is arbitrary and may be one. Even with this configuration, the inlet space R2 of the pressure sensor 20 and the internal space R3 of the inspection pipe 202 are in airtight communication.

[0050] The regulating member 212 may be biased towards the pressure sensor 20 either directly by an elastic body or via a sliding member or the like. The regulating member 212 may be spherical or the like, rather than being rod-shaped.

[0051] As shown in Figure 6, an inspection pipe 302 may be used. The inspection pipe 302 comprises a cylindrical body 302A that forms an internal space R3, and an annular flange 302B that protrudes outward from the upper end of the body 302A. The inspection pipe 202 comprises a cylindrical portion 302C that extends upward from the periphery of the flange 302B and surrounds the first cylindrical member 21A of the pressure sensor 20. The cylindrical portion 302C is formed to a height that covers the lower part of the recess 29. A sealing member 101 is positioned in the lower part of the recess 29.

[0052] The inspection pipe 302 and the pressure sensor 20 are clamped together by a plurality of arc-shaped connecting members 310 when viewed from above. Each connecting member 310 includes an insertion portion 311 that is inserted into the upper part of the recess 29 of the housing 21, and an engagement portion 312 that fits under the flange 302B of the inspection pipe 302 and engages with the lower surface of the flange 302B. The housing 21 and the inspection pipe 302 are clamped together by the insertion portion 311 and the engagement portion 312 via the sealing member 101. Even with this connection, the inlet space R2 of the pressure sensor 20 and the internal space R3 of the inspection pipe 302 are in airtight communication.

[0053] Various modifications may be applied to the above embodiments. For example, the shape of each component can be arbitrarily changed. For instance, a cylindrical shape may be changed to a polygonal tube shape with a polygonal cross-section, or vice versa. Each component may consist of a single integrally formed part, or it may be a combination of multiple parts.

[0054] Although the present invention has been described above with reference to embodiments and modifications, the present invention is not limited to the above embodiments and modifications. For example, the present invention includes various modifications to the above embodiments and modifications that can be understood by those skilled in the art within the scope of the technical concept of the present invention. The configurations listed in the above embodiments and modifications can be combined as appropriate to the extent that they do not contradict each other. [Explanation of symbols]

[0055] 10...Vacuum gauge, 20...Pressure sensor, 21...Housing, 21A...First cylindrical member, 21B...Second cylindrical member, 21C...Lid member, 22...Sensor element, 23...Sensor support part, 23A...Through hole, 24...Conductive pin, 29...Recess, 30...Heater, 31...Fixing part, 40...Bracket, 41...Cylindrical part, 42...Protruding part, 43...Through hole, 50...Tubular member, 51...Cylindrical part, 52...Flange, 53...Flange, 54...Lower end (one end), 55...Upper end (other end), 60...Baffle, 70...Control device, 101...Sealing member, 102...Inspection piping, 102A...Main body, 102B...Flange, 102BA...Recess 110...Connecting member, 111...First member, 111A...Insertion part, 112...Second member, 112A...Engaging part, 113...Bolt, 202...Inspection piping, 202A...Main body, 202B...Flange, 202C...Cylindrical part, 202CA...Through hole, 210...Connecting member, 211...Pressing member, 212...Regulating member, 212A...Insertion part, 212B...Engaging part, 212C...Regulating part, 302...Inspection piping, 302A...Main body, 302B...Flange, 302C...Cylindrical part, 310...Connecting member, 311...Insertion part, 312...Engaging part, G...Gas, H1...Wiring, H2...Wiring, R1...Reference vacuum chamber, R2...Inflow space, R3...Internal space.

Claims

1. A pressure sensor comprising a reference vacuum chamber and an inlet space into which gas from a space to be measured flows, and a first step of connecting the cylindrical portion forming the inlet space and an inspection pipe via a sealing member, the inlet space of the pressure sensor which converts the pressure difference between the reference vacuum chamber and the inlet space into an electrical signal, The process further includes a second step of performing a vacuum or applying pressure to the inflow space via the inspection piping after the first step, and inspecting the characteristics of the pressure sensor. The cylindrical portion is configured such that one end is formed as a joint for a vacuum gauge on which the pressure sensor is mounted, and the other end of a tubular member that introduces the gas flowing in from the one end to the other end is joined to it. In the first step, the cylindrical portion and the inspection pipe are connected by a connecting member having an insertion portion that is inserted into a recess provided on the outer surface of the pressure sensor and an engagement portion that engages with the inspection pipe. The housing of the pressure sensor comprises two members joined together, sandwiching the peripheral edge of the sensor support portion that supports the sensor element. One of the two members includes the cylindrical portion, The recess has a bottom surface that includes the joint between the two members. Method for inspecting pressure sensors.

2. A pressure sensor comprising a reference vacuum chamber and an inlet space into which gas from a space to be measured flows, and a first step of connecting the cylindrical portion forming the inlet space and an inspection pipe via a sealing member, the inlet space of the pressure sensor which converts the pressure difference between the reference vacuum chamber and the inlet space into an electrical signal, The process further includes a second step of performing a vacuum or applying pressure to the inflow space via the inspection piping after the first step, and inspecting the characteristics of the pressure sensor. The cylindrical portion is configured such that one end is formed as a joint for a vacuum gauge on which the pressure sensor is mounted, and the other end of a tubular member that introduces the gas flowing in from the one end to the other end is joined to it. In the first step, the cylindrical portion and the inspection pipe are connected by a connecting member having an insertion portion that is inserted into a recess provided on the outer surface of the pressure sensor and an engagement portion that engages with the inspection pipe. The inspection piping has a flange protruding from the upper end when the pressure sensor side is facing upward, The sealing member is sandwiched between the cylindrical portion and the flange. The insertion portion engages with the inner wall surface of the recess, The engagement portion engages with the lower surface of the flange, The connecting member clamps the pressure sensor and the inspection pipe with the insertion portion and the engagement portion. Method for inspecting pressure sensors.

3. A pressure sensor comprising a reference vacuum chamber and an inlet space into which gas from a space to be measured flows, and a first step of connecting the cylindrical portion forming the inlet space and an inspection pipe via a sealing member, the inlet space of the pressure sensor which converts the pressure difference between the reference vacuum chamber and the inlet space into an electrical signal, The process further includes a second step of performing a vacuum or applying pressure to the inflow space via the inspection piping after the first step, and inspecting the characteristics of the pressure sensor. The cylindrical portion is configured such that one end is formed as a joint for a vacuum gauge on which the pressure sensor is mounted, and the other end of a tubular member that introduces the gas flowing in from the one end to the other end is joined to it. In the first step, the cylindrical portion and the inspection pipe are connected by a connecting member having an insertion portion that is inserted into a recess provided on the outer surface of the pressure sensor and an engagement portion that engages with the inspection pipe. The inspection piping comprises a flange protruding from the upper end when the pressure sensor side is oriented upward, and a cylindrical portion extending upward from the peripheral edge of the flange and surrounding the cylindrical portion of the pressure sensor. The aforementioned connecting member is An annular retaining member that holds down the sealing member, which is positioned between the cylindrical portion of the inspection pipe and the cylindrical portion of the pressure sensor, A restricting member comprising: an insertion portion; an engagement portion that engages with the cylindrical portion of the inspection pipe through a through hole that penetrates the cylindrical portion of the inspection pipe; and a restricting portion located between the insertion portion and the engagement portion that restricts the upward movement of the retaining member, Method for inspecting pressure sensors.

4. A pressure sensor comprising a reference vacuum chamber and an inlet space into which gas from a space to be measured flows, and a first step of connecting the cylindrical portion forming the inlet space and the inspection piping via a sealing member, the inlet space of the pressure sensor which converts the pressure difference between the reference vacuum chamber and the inlet space into an electrical signal, The process further includes a second step of performing a vacuum or applying pressure to the inflow space via the inspection piping after the first step, and inspecting the characteristics of the pressure sensor. The cylindrical portion is configured such that one end is formed as a joint for a vacuum gauge on which the pressure sensor is mounted, and the other end of a tubular member that introduces the gas flowing in from the one end to the other end is joined to it. In the first step, the cylindrical portion and the inspection pipe are connected by a connecting member having an insertion portion that is inserted into a recess provided on the outer surface of the pressure sensor and an engagement portion that engages with the inspection pipe. The inspection piping comprises a flange protruding from the upper end when the pressure sensor side is oriented upward, and a cylindrical portion extending upward from the peripheral edge of the flange and surrounding the cylindrical portion of the pressure sensor. The cylindrical portion of the inspection pipe has a height that covers the lower part of the recess, The sealing member is positioned in the lower portion of the recess, The insertion portion is inserted into the upper part of the recess, The engagement portion engages with the lower surface of the flange, The connecting member clamps the pressure sensor and the inspection pipe via the sealing member between the insertion portion and the engaging portion. Method for inspecting pressure sensors.

5. A method for manufacturing a vacuum gauge, comprising a method for inspecting a pressure sensor according to any one of claims 1 to 4, A third step involves joining the tubular member to the cylindrical portion of the pressure sensor, A fourth step is to reflect the inspection results from the second step in a control unit mounted on the vacuum gauge together with the pressure sensor. A method for manufacturing a vacuum gauge.

6. A pressure sensor comprising a reference vacuum chamber and an inflow space into which gas from a space to be measured flows, which converts the pressure difference between the reference vacuum chamber and the inflow space into an electrical signal, A sensor element that converts the pressure difference into an electrical signal, A sensor support portion that supports the aforementioned sensor element, The housing comprises a cylindrical portion forming the inflow space, with one end formed as a joint for a vacuum gauge on which the pressure sensor is mounted, and the other end of a tubular member that introduces the gas flowing in from the one end to the other end being joined thereto, The housing comprises two members joined together, sandwiching the peripheral edge of the sensor support portion. One of the two members includes the cylindrical portion, A recess is formed on the outer surface of the housing, with the surface including the joint between the two members as its bottom surface. Pressure sensor.

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