Sensor device

Abstract

The rate of foreign matter accumulation is made different between the two pressure-receiving diaphragms. [Solution] The sensor device 10 comprises a sensor head 30 and a pressure sensing pipe 40. The sensor head 30 includes a plate-shaped baffle 36 and a porous baffle 37. The plate-shaped baffle 36 is positioned inside the pressure sensing pipe 31, facing the pressure-receiving diaphragm 32CA, and is positioned so as to come into contact with the fluid to be measured, which flows from the pressure sensing pipe 40 into the pressure sensing pipe 31 and heads toward the pressure-receiving diaphragm 32CA. The porous baffle 37 is also positioned inside the pressure sensing pipe 31, facing the pressure-receiving diaphragm 33CA, and comes into contact with the fluid to be measured, which flows from the pressure sensing pipe 40 into the pressure sensing pipe 31 and heads toward the pressure-receiving diaphragm 33CA. The porous baffle 37 is formed in a shape that is more likely to deactivate the fluid to be measured than the plate-shaped baffle 36.

Description

Technical Field

[0001] The present invention relates to a sensor device such as a vacuum gauge.

Background Art

[0002] As disclosed in Patent Document 1, a sensor device (vacuum gauge) for measuring the pressure of a fluid to be measured such as a gas is known. Such a sensor device includes a pressure sensor. The pressure sensor includes a pressure-receiving diaphragm that receives the pressure of the fluid to be measured, and is configured to convert the pressure received by this pressure-receiving diaphragm into an electrical signal. Further, the sensor device also includes a baffle against which the fluid to be measured hits before reaching the pressure-receiving diaphragm. When the fluid to be measured hits this baffle, the deposition of foreign substances on the pressure-receiving diaphragm due to the fluid to be measured is suppressed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Sensor devices have a fixed measurement range for pressure measurement. Therefore, when a wider range of pressure measurement is required, multiple sensor devices with different measurement ranges are used in combination. Also, to ensure redundancy in case of pressure sensor failure, it is conceivable to use multiple sensor devices with the same measurement range. Using multiple sensor devices in combination results in poor space efficiency in terms of installation space, and improvement in this regard is desirable. For example, in semiconductor manufacturing equipment, there is a tendency to employ compact pressure adjustment chambers, and improving the aforementioned space efficiency is important. Therefore, the inventors of the present invention conceived of mounting at least two pressure sensors on a single sensor device and providing a total of two baffles, one for each of the two pressure sensors, in order to improve space efficiency. Furthermore, the inventors of the present invention found that it is useful to use two different types of baffles to make the rate of accumulation of foreign matter caused by the measured fluid different between the pressure-receiving diaphragms of the two pressure sensors. For example, it is possible to detect malfunctions due to an increase in the amount of foreign matter accumulated in the pressure-receiving diaphragm with the faster accumulation rate.

[0005] The present invention aims to make the rate of foreign matter accumulation different between two pressure-receiving diaphragms. [Means for solving the problem]

[0006] The sensor device according to this invention comprises a sensor head including a first pipe extending in a first direction, a first pressure sensor fixed to a first end of the first pipe, and a second pressure sensor fixed to a second end of the first pipe different from the first end, and a second pipe extending in a second direction different from the first direction and connected in the middle of the first pipe, which guides the pressure of the fluid to be measured to the first pressure sensor and the second pressure sensor via the first pipe, wherein the first pressure sensor includes a first pressure receiving diaphragm that receives the pressure of the fluid to be measured and converts the pressure received by the first pressure receiving diaphragm into a first electrical signal, and the second pressure sensor includes a second pressure receiving diaphragm that receives the pressure of the fluid to be measured and converts the pressure received by the second pressure receiving diaphragm into a second electrical signal Instead, the sensor head further includes: a first baffle disposed inside the first pipe and facing the first pressure-receiving diaphragm, which reduces a first accumulation amount, which is the amount of foreign matter accumulated on the first pressure-receiving diaphragm, by contact with the fluid to be measured flowing from the second pipe into the first pipe and toward the first pressure-receiving diaphragm; and a second baffle disposed inside the first pipe and facing the second pressure-receiving diaphragm, which reduces a second accumulation amount, which is the amount of foreign matter accumulated on the second pressure-receiving diaphragm, by contact with the fluid to be measured flowing from the second pipe into the first pipe and toward the second pressure-receiving diaphragm, the second baffle being shaped to reduce the second accumulation amount by a larger amount than the reduction of the first accumulation amount by the first baffle. [Effects of the Invention]

[0007] According to the present invention, the rate of foreign matter accumulation can be made different between the two pressure-receiving diaphragms. [Brief explanation of the drawing]

[0008] [Figure 1] This is an exploded perspective view of a sensor device relating to one embodiment of the present invention. [Figure 2] This is an exploded perspective view of the sensor section of the sensor device. [Figure 3] This is an exploded perspective view of the heater covering the sensor head of the sensor unit. [Figure 4] This is a schematic cross-sectional view of the sensor device, and the inside of the sensor head is shown only in the cross-sectional view where appropriate, with only the cut end faces visible. [Figure 5] This is a schematic cross-sectional view of a part of the sensor device. [Figure 6] This is a perspective view of the pressure sensing pipe and two baffles of the sensor head. [Figure 7] This is an exploded perspective view of a perforated baffle cut in half. [Figure 8] This is an enlarged view of the X portion in Figure 7. [Figure 9] This is a block diagram of the main components of the sensor device. [Figure 10] This is a flowchart of the measurement and diagnostic process performed by the arithmetic circuit. [Modes for carrying out the invention]

[0009] (Summary of the embodiment) The inventors of the present invention have found the following: First, by using a dual number of pressure sensors in a sensor device for measuring the pressure of a fluid to be measured (e.g., a vacuum gauge), the overall size can be reduced compared to a sensor device with multiple sensors, each equipped with a single pressure sensor. In a sensor device with dual pressure sensors, the sensor head includes a first pipe extending in a first direction, and first and second pressure sensors fixed to both ends of this first pipe, respectively. Furthermore, a second pipe is connected to the first pipe to guide the pressure of the fluid to be measured to the first and second pressure sensors via the first pipe. The first pressure sensor has a first pressure-receiving diaphragm used to detect the pressure of the fluid to be measured, and the second pressure sensor has a second pressure-receiving diaphragm used to detect the pressure of the fluid to be measured.

[0010] In such a sensor device, first and second baffles are provided in the flow path of the fluid to be measured, facing the first and second pressure-receiving diaphragms, respectively. The first baffle functions as a barrier that the fluid to be measured encounters before it reaches the first pressure-receiving diaphragm. The fluid to be measured is also an active gas, and if the first baffle is not provided, when the fluid to be measured encounters the first pressure-receiving diaphragm, the active substances constituting the fluid react with the surface of the first pressure-receiving diaphragm and accumulate on the first pressure-receiving diaphragm as foreign matter. The first baffle has the function of reducing the amount of this foreign matter that accumulates. The second baffle functions as a barrier that the fluid to be measured encounters before it reaches the second pressure-receiving diaphragm. If the second baffle is not provided, when the fluid to be measured encounters the second pressure-receiving diaphragm, the active substances constituting the fluid react with the surface of the second pressure-receiving diaphragm and accumulate on the second pressure-receiving diaphragm as foreign matter. The second baffle has the function of reducing the amount of this foreign matter that accumulates.

[0011] In this embodiment, the first baffle and the second baffle are of different types (structures), thereby enabling diagnosis of deterioration in measurement accuracy due to the accumulation of foreign matter on the diaphragm. Specifically, the following are considered.

[0012] There are two types of baffles: a flat plate baffle, which is a single plate-shaped baffle, and a porous baffle, which has many through-holes through which the fluid to be measured passes. Here, we assume that the flat plate baffle is placed opposite the first pressure-receiving diaphragm, and the porous baffle is placed opposite the second pressure-receiving diaphragm.

[0013] The flat baffle has a surface on which foreign matter accumulates when it comes into contact with the fluid being measured, reacting with the active substances constituting the fluid. This accumulation reduces the amount of foreign matter that accumulates on the first pressure-receiving diaphragm.

[0014] Each through-hole of the porous baffle is formed with a fine structure and a meandering shape. With such a structure, each through-hole forms a fine and long flow path as a flow path for the fluid to be measured. The fluid to be measured hits the inner wall surface of the through-hole many times as it passes through this through-hole, and as a result, it is deactivated. Due to this deactivation, the amount of foreign matter deposited on the second pressure-receiving diaphragm is reduced. The reduction amount of the deposited amount of this foreign matter is larger than the reduction amount by the plate-shaped baffle. Also, the amount of foreign matter deposited on the porous baffle due to the fluid to be measured is less than that on the flat baffle.

[0015] Also, between the first and second pressure sensors, at least a part of the pressure detection ranges overlaps. From these, when the same pressure measurement value cannot be obtained between the first pressure sensor and the second pressure sensor, it becomes reasonable to presume that there is a defect in the first pressure-receiving diaphragm on the flat baffle side where foreign matter is likely to accumulate a lot. That is, an additional function of defect diagnosis of the pressure-receiving diaphragm or pressure sensor using different types of baffles can be obtained.

[0016] (Details of the Embodiment) Hereinafter, the details of the embodiment of the present invention will be described with reference to the drawings. In this embodiment, the up-down direction, left-right direction, and front-back direction that are orthogonal to each other are set, but these directions are not intended to indicate the mounting direction of the sensor device. For example, the up-down direction may coincide with the horizontal direction depending on the orientation of the sensor device 10. Also, for a plurality of similar elements, only some of the elements are appropriately labeled.

[0017] The sensor device 10 shown in FIG. 1 is connected to a pipe connected to a pressure adjustment chamber (for example, a vacuum chamber) in a semiconductor control device or the like, and measures the pressure of the fluid to be measured (for example, the atmospheric pressure of a process gas) introduced from the pressure adjustment chamber into the pipe by a diaphragm that receives this pressure, and is configured as a diaphragm vacuum gauge.

[0018] The sensor device 10 includes a sensor unit 20 that detects the pressure of the fluid to be measured by converting the pressure into an electrical signal and outputs the detected pressure, i.e., the electrical signal indicating the pressure, as a pressure detection signal, and a control unit 90 that controls the operation of the sensor unit 20, processes the pressure detection signal from the sensor unit 20, and outputs the pressure of the fluid to be measured indicated by the pressure detection signal to the outside. The pressure of the fluid to be measured is measured by this pressure derivation. The control unit 90 includes a circuit board, connectors, communication modules, etc., for pressure derivation and external output, and a housing 91 that houses these. The housing 91 is simplified in Figure 1, and in reality, it has vents for cooling the circuit board and various connectors are attached to it.

[0019] As shown in Figures 1 to 3, the sensor unit 20 includes a sensor head 30, a pressure sensing pipe 40, a heater 50, a fixing mechanism 60, a heat insulating member 70, and a bracket 80.

[0020] As shown in Figures 3 and 4, the sensor head 30 comprises a cylindrical pressure-sensing pipe 31 extending in the left-right direction, pressure sensors 32 and 33 fixed to the openings at both ends of the pressure-sensing pipe 31, and insulators 34 and 35 fixed to the pressure sensors 32 and 33 by fasteners (not shown) or any joining method.

[0021] The upper end of a cylindrical pressure sensing pipe 40, which extends vertically, is connected to the middle of the pressure sensing pipe 31 (in this case, at the center in the left-right direction). The combination of pressure sensing pipes 31 and 40 forms a T-shape, with pressure sensing pipe 31 acting as the horizontal bar of a T and pressure sensing pipe 40 acting as the vertical bar of a T.

[0022] As shown in Figures 2 and 3, the pressure sensing pipe 40 has a joint 41 at its lower end. This joint 41 is connected to the piping. The pressure of the fluid to be measured, introduced from the piping to the pressure sensing pipe 40 via the joint 41, is introduced to the pressure sensors 32 and 33 via the pressure sensing pipe 31 (see also the cross-sectional view in Figure 4).

[0023] As shown in Figure 4, the pressure sensor 32 comprises a housing 32A, a support diaphragm 32B, a sensor element 32C, a plurality of conductive pins 32D, a plurality of spring contacts 32E, and a sealing member 32F. In the cross-sectional view of Figure 4, the plurality of conductive pins 32D and the plurality of spring contacts 32E are depicted as elevation views rather than cross-sections. The number of conductive pins 32D and spring contacts 32E is arbitrary. In Figure 4, the thicknesses of the support diaphragm 32B and the sensor element 32C (especially the pressure-receiving diaphragm 32CA, which will be described later) are exaggerated. The same applies to the pressure sensor 33.

[0024] The housing 32A comprises a cylindrical housing member 32AA, a plate-shaped housing member 32AB that covers the opening at one end (the right end in this case) of the housing member 32AA, and an annular housing member 32AC connected to the other end of the housing member 32AA. The housing members 32AA and 32AC support the support diaphragm 32B by sandwiching its peripheral edge. The support diaphragm 32B supports the sensor element 32C. Together with the support diaphragm 32B and the sensor element 32C, the housing members 32AA and 32AB form a reference pressure chamber (e.g., a vacuum chamber) R11 having a reference pressure (e.g., a vacuum pressure). The housing member 32AC is connected to one end (the right end) of the pressure sensing pipe. Together with the support diaphragm 32B and the sensor element 32C, the housing member 32AC forms a pressure chamber R12 to be measured. The pressure chamber R12 under test is connected to the internal space of the pressure sensing pipe 31, and the pressure of the fluid under test is transmitted to the pressure chamber R12 when the fluid under test flows into it from the pressure sensing pipe 31.

[0025] The sensor element 32C introduces the fluid to be measured (more specifically, the pressure of the fluid to be measured) into the pressure chamber R12. The sensor element 32C includes a pressure-receiving diaphragm 32CA that receives the pressure of the fluid to be measured introduced inside. The pressure-receiving diaphragm 32CA faces the reference pressure chamber R11 and displaces with a degree of displacement corresponding to the difference between the pressure of the fluid to be measured and the reference pressure of the reference pressure chamber R11. The sensor element 32C converts the amount of displacement of the pressure-receiving diaphragm 32CA (i.e., the pressure received by the pressure-receiving diaphragm 32CA) into an electrical signal and outputs it. The sensor element 32C can be any type of pressure-sensitive element. The sensor element 32C may be a capacitive pressure-sensitive element that converts the amount of displacement of the pressure-receiving diaphragm 32CA into an electrical signal indicating a change in capacitance, or it may be a type of pressure-sensitive element that converts the amount of displacement of the pressure-receiving diaphragm 32CA into an electrical signal using one or more piezoelectric elements (not shown). In the former case, the sensor element 32C in Figure 4 further has a member to the right of the pressure-receiving diaphragm 32CA that forms a volume chamber into which the air pressure of the reference pressure chamber R11 is introduced.

[0026] Each of the multiple spring contacts 32E is connected to the sensor element 32C. Multiple conductive pins 32D are connected one-to-one with the multiple spring contacts 32E. The multiple conductive pins 32D are supported by the housing 32A, for example, by hermetic seals, passing through the housing member 32AC of the housing 32A. Each portion of the multiple conductive pins 32D that protrudes outside the housing 32A is covered and insulated by an insulator 34 fixed to the pressure sensor 32 and is connected to the control unit 90 via wiring (not shown).

[0027] The sealing member 32F seals the through-hole H1 of the housing member 32AA, which forms the reference pressure chamber R11. During the manufacturing of the pressure sensor 32, the reference pressure chamber R11 is evacuated through the through-hole H1. The sealing member 32F is provided to seal the through-hole H1 after the evacuation is complete.

[0028] With the above configuration, the pressure sensor 32 receives the pressure of the fluid to be measured, introduced via the pressure sensing pipes 40 and 31, with the pressure receiving diaphragm 32CA. The pressure received by the pressure receiving diaphragm 32CA is converted into an electrical signal, and this electrical signal is supplied to the control unit 90 via wiring as a pressure detection signal. The pressure sensor 32 detects the pressure by converting the pressure into an electrical signal. The control unit 90 processes the pressure detection signal and derives the pressure of the fluid to be measured indicated by the pressure detection signal. This completes the pressure measurement. The control unit 90 outputs the derived, i.e., measured, pressure to an external device via a connector (not shown).

[0029] The pressure sensor 33 has the same configuration as the pressure sensor 32. That is, the pressure sensor 33 comprises a housing 33A (housing members 33AA to 33AC), a support diaphragm 33B, a sensor element 33C, a plurality of conductive pins 33D, a plurality of spring contacts 33E, and a sealing member 33F. The housing members 33AA and 33AB of housing 33A, together with the support diaphragm 33B which is supported between housing members 33AA and 33AC, and the sensor element 33C which is fixed to and supported by the support diaphragm 33B, form a reference pressure chamber R21. The through hole H1 of housing member 33AA is sealed by the sealing member 33F. The housing member 33AC of housing 33A, together with the support diaphragm 33B and the sensor element 33C, forms a pressure chamber R22. The sensor element 33C includes a pressure receiving diaphragm 33CA. Each portion of the multiple conductive pins 33D that protrudes outside the housing 33A is covered and insulated by an insulator 35 fixed to the pressure sensor 33 and connected to the control unit 90 via wiring (not shown). With this configuration, the pressure sensor 33 converts the pressure of the fluid to be measured, introduced via the pressure sensing pipes 40 and 31, into an electrical signal (more specifically, an electrical signal indicating the displacement of the pressure-receiving diaphragm 33CA), and supplies this electrical signal as a pressure detection signal to the control unit 90 via multiple wires. The control unit 90 processes the pressure detection signal, derives the pressure of the fluid to be measured indicated by the pressure detection signal, and outputs it externally via a connector (not shown) or the like.

[0030] The pressure detection ranges for the fluid being measured by pressure sensors 32 and 33 are different from each other. Specifically, pressure sensor 32 has a low-pressure detection range, and pressure sensor 33 has a high-pressure detection range. This enables a wide range for the overall pressure detection range of the sensor device 10. The high-pressure detection range is located on the higher pressure side than the low-pressure detection range, but there is some overlap between the two pressure detection ranges. For example, the upper limit of the high-pressure detection range should be higher than the upper limit of the low-pressure detection range, the lower limit of the high-pressure detection range should be higher than the lower limit of the low-pressure detection range, and the lower limit of the high-pressure detection range should be lower than the upper limit of the low-pressure detection range. The pressure detection range is adjusted, for example, by the materials and / or thicknesses of the pressure-receiving diaphragms 32CA and 33CA.

[0031] As shown in Figures 4 to 6, the sensor head 30 further comprises a plate-shaped baffle 36 and a porous baffle 37.

[0032] The plate-shaped baffle 36 is formed as a single plate. The plate-shaped baffle 36 comprises a plate-shaped baffle body 36A and three protruding portions 36B extending radially from the baffle body 36A. In this embodiment, the baffle body 36A is formed in a disc shape, but it may be formed in a polygonal plate shape or the like. The three protruding portions 36B are fixed to the annular surface 31A of the inner surface of the pressure sensing pipe 31, which faces to the right and is the side of the pressure receiving diaphragm 32CA, by welding, screwing, etc. As a result, the plate-shaped baffle 36 is placed inside the pressure sensing pipe 31 and supported by the pressure sensing pipe 31. The plate-shaped baffle 36 faces the sensor element 32C of the pressure sensor 32, in particular the pressure receiving diaphragm 32CA. The plate-shaped baffle 36 has an in-plane direction perpendicular to the left-right direction, which is the direction in which the pressure sensing pipe 31 extends. The plate-shaped baffles 36 are provided parallel to the pressure receiving diaphragm 32CA. The plate-shaped baffle 36 is positioned inside the pressure sensing pipe 31, closer to the pressure sensor 32 than to the pressure sensing pipe 40. As a result, the baffle 36 is located upstream of the pressure sensor 32.

[0033] As shown by arrow A1 in Figure 4, the fluid to be measured, which flows from the pressure sensing pipe 40 into the pressure sensing pipe 31 and then towards the pressure sensor 32, hits the baffle 36 along the way and flows into the pressure chamber R12. Specifically, upon hitting the baffle 36, the fluid to be measured curves around the outer circumference of the baffle body 36A and flows into the pressure chamber R12 through the gap between the baffle 36 and the inner surface of the pressure sensing pipe 31. The fluid to be measured that has flowed into the pressure chamber R12 reaches the pressure sensor 32, and its pressure is detected. On the surface of the baffle 36 that the fluid to be measured hits (the side facing left), foreign matter accumulates due to the reaction between the surface and the active substance that makes up the fluid to be measured (active gas). This accumulation reduces the amount of active substance, and thus reduces the amount of foreign matter that accumulates on the pressure receiving diaphragm 32CA located downstream of the baffle 36.

[0034] As shown in Figures 4, 6-8, the perforated baffle 37 is formed in a cylindrical shape overall and extends in the left-right direction, which is the direction in which the pressure sensing pipe 31 extends. In other words, the perforated baffle 37 has a central axis that extends in the left-right direction. Note that in the drawings, the perforated baffle 37 is depicted in a simplified manner. The perforated baffle 37 is fixed to the annular surface 31B of the inner surface of the pressure sensing pipe 31, which faces left, on the side of the pressure receiving diaphragm 33CA, by welding, screwing, etc. Thus, the perforated baffle 37 is positioned inside the pressure sensing pipe 31 and supported by the pressure sensing pipe 31. The perforated baffle 37 faces the sensor element 33C of the pressure sensor 33, in particular the pressure receiving diaphragm 33CA. The perforated baffle 37 is provided parallel to the pressure receiving diaphragm 33CA. The perforated baffle 37 is positioned inside the pressure sensing pipe 31, on the side of the pressure sensor 33 that is closer to the pressure sensing pipe 40. As a result, the porous baffle 37 is located upstream of the pressure sensor 33.

[0035] The perforated baffle 37 is configured as a laminated baffle including a plurality of plate-like members stacked in the left-right direction, which is the direction in which the pressure-sensing pipe 31 extends, by welding, thermocompression, screw fastening, etc. (see Figure 7 in particular). The plurality of plate-like members are stacked coaxially in the left-right direction. Each of the plurality of plate-like members has an in-plane direction perpendicular to the left-right direction and is parallel to the pressure-receiving diaphragm 33CA. The perforated baffle 37 comprises a first plate-like portion 37A, a cylindrical portion 37B extending to the right from the first plate-like portion 37A (in the direction opposite to the side of the pressure-receiving diaphragm 33CA), and a second plate-like portion 37C fixed to the right end of the cylindrical portion 37B.

[0036] The first plate-like portion 37A consists of a single plate-like member and is formed in a disc shape. The first plate-like portion 37A comprises a central portion 37AA and an annular peripheral portion 37AB surrounding the central portion 37AA. On the right main surface of the annular peripheral portion 37AB, that is, the main surface opposite to the surface facing the pressure-receiving diaphragm 33CA, a protrusion similar to the protrusion 37ZA described later is formed.

[0037] The cylindrical portion 37B extends to the right from the annular peripheral portion 37AB in the direction opposite to the direction toward the pressure-receiving diaphragm 33CA. The cylindrical portion 37B is cylindrical in shape. The cylindrical portion 37B has a central axis extending in the left-right direction. As shown in Figure 7, the cylindrical portion 37B is formed by stacking multiple donut-shaped plate members 37Z that have the same structure as each other. In Figure 7, only a portion of the multiple plate members 37Z is shown; in reality, more than 3 (for example, 20) plate members 37Z are stacked. In Figures 4 and 6, the cylindrical portion 37B is simplified and depicted as a single component, and lines indicating the stacked plate members 37Z, the through-holes 37H described later, etc. are omitted.

[0038] As shown in Figures 7 and 8, the plate-shaped member 37Z has a number of meandering linear protrusions 37ZA extending radially from the center of the plate-shaped member 37Z at intervals from each other, on the main surface opposite to the main surface facing the pressure-receiving diaphragm 33CA (the main surface facing to the right). In Figure 8, a dot pattern is applied to the top surface of the protrusions 37ZA for visibility. As shown in Figure 8, a space 37H is formed between adjacent protrusions 37ZA. When multiple plate-shaped members 37Z are stacked, the top surface of the protrusions 37ZA is joined or in close contact with the left side surface of the plate-shaped member 37Z to its right (the surface facing the pressure-receiving diaphragm 33CA). As a result, the space 37H between adjacent protrusions 37ZA becomes a through hole that penetrates the cylindrical portion 37B radially and has openings at both ends on the inner and outer surfaces of the cylindrical portion 37B. Hereafter, this through hole will also be referred to as the through hole 37H. With the above configuration, the cylindrical portion 37B is provided with numerous fine through-holes 37H, thereby giving the porous baffle 37 a porous structure. Each through-hole 37H is separated by adjacent meandering protrusions 37ZA, and thus extends meanderingly from the inner circumferential surface to the outer circumferential surface of the cylindrical portion 37B. Each through-hole 37H becomes a meandering flow path through which the fluid to be measured flows (see arrow A3 in Figure 8), as described later. As mentioned above, the first plate-like portion 37A also has protrusions similar to the protrusions 37ZA, thereby forming through-holes similar to the through-holes 37H. For convenience, these through-holes will also be called through-holes 37H.

[0039] The second plate-shaped portion 37C is formed in a disc shape and covers the cylindrical portion 37B from the right side (opposite side of the pressure-receiving diaphragm 33CA). As a result, the top of the convex portion 37ZA of the rightmost plate-shaped member 37Z of the cylindrical portion 37B is joined to or in close contact with the second plate-shaped portion 37C, thereby forming a through hole 37H. The second plate-shaped portion 37C has multiple through holes 37CA in its central part, which covers the central space of the cylindrical portion 37B.

[0040] As shown by arrow A2 in Figure 4, the fluid to be measured, after flowing from the pressure sensing pipe 40 into the pressure sensing pipe 31 and then toward the pressure sensor 33, strikes the porous baffle 37 along the way and flows into the pressure chamber R22. Specifically, the fluid to be measured flows from multiple through holes 37CA (Figures 6 and 7) in the second plate-shaped part 37C into the internal space of the cylindrical part 37B, passes through numerous through holes 37H (space 37H in Figure 8) in the cylindrical part 37B, and flows out into the outer space of the porous baffle 37, i.e., the pressure chamber R22 (see arrow A3 in Figure 8). The fluid to be measured that has flowed out into the pressure chamber R22 reaches the pressure sensor 33, and its pressure is detected. As the fluid to be measured flows parallel to the numerous meandering fine through holes 37H (meandering flow path), the fluid to be measured strikes the inner wall surface of the through holes 37H many times and is deactivated. This is due to the fineness of the through-holes 37H and the increased flow path length caused by their meandering shape. With this configuration, the porous baffle 37 suppresses the accumulation of foreign matter on itself while also reducing the amount of foreign matter accumulated on the pressure-receiving diaphragm 33CA. The effect of reducing foreign matter accumulation is greater with the porous baffle 37 than with the plate-shaped baffle 36. In other words, in this embodiment, foreign matter is more likely to accumulate on the pressure-receiving diaphragm 32CA facing the plate-shaped baffle 36 than on the pressure-receiving diaphragm 33CA facing the porous baffle 37.

[0041] The shape of the porous baffle 37 is arbitrary and may be formed in the shape of a polygonal prism, for example. In such a case, the first plate-like portion 37A and the second plate-like portion 37C may be formed in the shape of a polygon, and the cylindrical portion 37B may be formed in the shape of a polygonal cylinder. The protrusions 37ZA and through holes 37H may be shaped in a way that can deactivate the fluid to be measured, for example, they may be curved. The cylindrical portion 37B is a member having a number of through holes formed from the inner circumferential surface to the outer circumferential surface, and may be formed as a single integrally formed member. At least two of the first plate-like portion 37A, the cylindrical portion 37B, and the second plate-like portion 37C may be integrally formed as a single member.

[0042] The way the pressure-receiving diaphragm 32CA is displaced by the pressure of the fluid being measured changes depending on the amount of foreign matter accumulated on the pressure-receiving diaphragm 32CA. Therefore, as the amount of accumulated foreign matter increases, the measurement error of the pressure of the fluid being measured, as measured by the control unit 90 using the pressure sensor 32, increases. This also applies to the pressure-receiving diaphragm 33CA and the sensor element 32C. As explained above, the amount of foreign matter accumulated on the pressure-receiving diaphragm 33CA is less than that on the pressure-receiving diaphragm 32CA, so the measurement error is larger on the pressure sensor 32. In this embodiment, the difference in the amount of foreign matter accumulated is used to diagnose the deterioration of pressure measurement due to foreign matter on the pressure sensor 32 side. This point will be described later.

[0043] As shown in Figures 3 to 5, the heater 50 is formed in a cylindrical shape that covers the sensor head 30 which extends in the left-right direction, and has an opening 50A through which the pressure sensing pipe 40 passes. The heater 50 heats the sensor head 30, in particular the pressure sensors 32 and 33, when measuring the pressure of the fluid to be measured. The heater 50 operates as a single heater and is shared for heating the pressure sensing pipe 31 and the pressure sensors 32 and 33, respectively.

[0044] The heating of the heater 50 is controlled by the control unit 90 shown in Figure 1. Specifically, the control unit 90 uses the temperature detected by the temperature sensor S (see Figure 4), which is located in the sensor head 30 and connected to the control unit 90 via wiring not shown, as a feedback value to feedback control the power supplied to the heater 50 so that the detected temperature approaches the target temperature. The target temperature is preset as the temperature at which the temperature of the sensor head 30, particularly the pressure sensors 32 and 33, is the same as the temperature of the fluid being measured. The position of the temperature sensor S is arbitrary. The temperature sensor S may be located inside the sensor head 30, for example, in the reference pressure chamber R11 or R21, or inside the pressure sensing pipe 31, or on the heater 50. Since the heater 50 is configured as a single heater, it is controlled by one temperature control using one temperature sensor S.

[0045] The heater 50 comprises a heater body 51 and 52 that generate heat, and support members 53 and 54 that support the heater body 51 and 52, respectively. These members are provided with semicircular notches that form an opening 50A.

[0046] Each of the heater bodies 51 and 52 is formed in a semi-cylindrical shape. The heater bodies 51 and 52 are connected to the control unit 90 by wiring (not shown) and generate heat uniformly when power is supplied from the control unit 90. This heat heats the sensor head 30, particularly the pressure sensors 32 and 33 and the pressure-conducting pipe 31. The control unit 90 acquires the temperature detected by the temperature sensor S (see Figure 4) by wiring (not shown) and uses the acquired temperature as a feedback value to feedback control the power supplied to the heater bodies 51 and 52 so that the detected temperature approaches the target temperature. The target temperature is preset as the temperature at which the temperature of the sensor head 30, particularly the pressure sensors 32 and 33, is the same as the temperature of the fluid being measured. The heater bodies 51 and 52 have a structure in which, for example, a heating wire passes through the inside for generating heat. The cross-sections of the heater bodies 51 and 52 in Figure 5 are shown in a manner in which the internal structure such as the heating wire is omitted.

[0047] The support member 53 is formed in a semi-cylindrical shape to match the shape of the heater body 51. The support member 53 supports the heater body 51 in such a manner that its outer circumferential surface supports the inner circumferential surface of the heater body 51. Support methods include joining the outer and inner circumferential surfaces with adhesive or adhesive tape, or fixing with screws. Similarly, the support member 54 is formed in a semi-cylindrical shape to match the shape of the heater body 52. ​​The support member 54 supports the heater body 52 in such a manner that its outer circumferential surface supports the inner circumferential surface of the heater body 52.

[0048] The heater 50 is fixed to the sensor head 30 by a fixing mechanism 60. The fixing mechanism 60 has cylindrical bosses 61 and 62 that protrude in the front-rear direction from the outer surface of the sensor head 30 (specifically, the center of the pressure sensing pipe 31 in the left-right direction), and screws 63 and 64 that are screwed into the bosses 61 and 62, respectively. In Figure 5, the screws 63 and 64 are shown in elevation views, not cross-sections.

[0049] As shown in Figures 3 and 5, the support members 53 and 54 of the heater 50 are screwed to bosses 61 and 62 with screws 63 and 64, respectively, while supporting the heater bodies 51 and 52. This fixes the heater 50 to the sensor head 30.

[0050] The heat insulating member 70 surrounds the sensor head 30 and the heater 50, reducing the heat dissipation from the heater 50 to the outside when heating the sensor head 30. As shown in Figures 2 and 4, the heat insulating member 70 comprises a substantially disc-shaped insulating material 71 that covers the sensor head 30 and the heater 50 from above, a support member 72 that supports the insulating material 71 from below, and a cylindrical support member 73 that supports the support member 72. The heat insulating member 70 further comprises a cylindrical insulating material 74 that surrounds the sensor head 30 and the heater 50 in the front, back, left, and right directions, and a substantially disc-shaped insulating material 75 that covers the sensor head 30 and the heater 50 from below.

[0051] The thermal insulation materials 74 and 75 are placed inside the support member 73. Thermal insulation material 74 is positioned on top of thermal insulation material 75. The support member 72 is provided with through-holes 72A through which multiple wires that electrically connect the control unit 90 and the sensor head 30 pass. Part of the through-holes 72A is blocked by the thermal insulation material 74, and the wires pass through the remaining part that is not blocked by the thermal insulation material 74. The thickness of the thermal insulation material 74 may be increased so that it completely covers the through-holes 72A. In this case, the wires are arranged to pass through the through-holes 72A, pushing aside the thermal insulation material 74.

[0052] The thermal insulation materials 71, 74, and 75 may consist of a combination of a flexible thermal insulation material body that provides thermal insulation and a thin plate member that adds rigidity to the thermal insulation material body. The thermal insulation material 75 has a through hole 75A in the center into which the pressure sensing pipe 40 is inserted. The thermal insulation material 75 also has a notch 75B for expanding the diameter of the through hole 75A. This allows the joint 41 to pass through the through hole 75A by expanding the diameter of the through hole 75A when the pressure sensing pipe 40 is passed through the thermal insulation material 75.

[0053] As shown in Figures 1, 2, and 4, the bracket 80 includes a plurality of bracket members 81 and 82 that face each other in the left-right direction from which the sensor head 30 extends and are combined with each other, and is formed as a whole into a cup shape. This bracket 80 is fixed to the control unit 90 while housing the sensor head 30, the upper part of the pressure sensing pipe 40, the heater 50, the fixing mechanism 60, and the heat insulating member 70. Here, it is fixed to the housing 91 of the control unit 90 by screws (not shown).

[0054] Here, the details of diagnosing the deterioration of pressure measurement on the pressure sensor 32 side will be explained. This diagnosis is performed by the calculation circuit 95 shown in Figure 9, which is mounted on the circuit board of the control unit 90. The calculation circuit 95 may consist of a processor such as a CPU (Central Processing Unit). The processor may include an ASIC (Application Specific Integrated Circuit) and / or an FPGA (Field Programmable Gate Array). In diagnosing the deterioration of pressure measurement, the pressure measured by the pressure sensor 33, which includes a pressure-receiving diaphragm 33CA with a slow rate of foreign matter accumulation due to the porous baffle 37, is used as a reference, and this pressure is compared with the pressure measured by the pressure sensor 32, which includes a pressure-receiving diaphragm 32CA with a fast rate of foreign matter accumulation due to the plate-shaped baffle 36. If the two are far apart, it is diagnosed that a large amount of foreign matter has accumulated on the pressure-receiving diaphragm 32CA, and that the pressure measurement by the pressure sensor 32 has deteriorated.

[0055] When the calculation circuit 95 receives pressure detection signals from pressure sensors 32 and 33, it performs the measurement diagnostic processing shown in Figure 10. Specifically, the calculation circuit 95 derives (measures) the pressure of the non-measured fluid as the first pressure based on the pressure detection signal received from pressure sensor 32, and derives (measures) the pressure of the non-measured fluid as the second pressure based on the pressure detection signal received from pressure sensor 33 (step S11). Subsequently, the calculation circuit 95 determines whether the derived second pressure falls within the overlapping range where the pressure detection range of pressure sensor 32 and the pressure detection range of pressure sensor 33 overlap (step S12). If the second pressure falls within the overlapping range (step S12: Yes), the calculation circuit 95 compares the derived first pressure and second pressure and determines whether they are the same or different (step S13). The difference between the two is determined by whether the difference between the first pressure and the second pressure exceeds a predetermined threshold. If the difference is less than or equal to the predetermined threshold, they are determined to be the same. If the difference is greater than a predetermined threshold, the two are determined to be different (the dissociation between them is large).

[0056] If the calculation circuit 95 determines that the first pressure and the second pressure are the same (step S13; same), it means that the amount of foreign matter accumulated on the pressure-receiving diaphragm 32CA is still small and the pressure measurement has not deteriorated. In such a case, the calculation circuit 95 outputs the first or second pressure, selected according to a predetermined criterion, as the measurement result of the pressure of the fluid being measured (step S14). The external output includes transmitting the pressure to a display device connected to the sensor device 10, a host device, a user terminal, etc. The external output also includes displaying the pressure on a predetermined display device (hereinafter the same).

[0057] If the calculation circuit 95 determines that the first pressure and the second pressure are different (step S13; same), the amount of foreign matter accumulated on the pressure-receiving diaphragm 32CA increases, and the pressure measurement deteriorates. In such a case, the calculation circuit 95 outputs the second pressure as the measured pressure of the fluid being measured, and also outputs information indicating that a large amount of foreign matter has accumulated on the pressure-receiving diaphragm 32CA (step S15). An example of such information is that the pressure measurement of the pressure sensor 32 has deteriorated due to the accumulation of foreign matter.

[0058] If the calculation circuit 95 determines that the derived second pressure is not within the overlapping range where the pressure detection range of pressure sensor 32 and the pressure detection range of pressure sensor 33 overlap (step S12; No), then either the first pressure or the second pressure is an abnormal value outside the pressure detection range. The calculation circuit 95 outputs the pressure that is not an abnormal value, i.e., the pressure within the pressure detection range, as the measured pressure of the fluid to be measured (step S16).

[0059] Next, the response speed of pressure detection based on the relationship between the pressure sensors 32 and 33 and the baffles 36 and 37 will be described. The response speed refers to the period from when the pressure of the fluid to be measured changes until the changed pressure is detected by the first pressure sensor or the second pressure sensor. As described above, the pressure detection range of the pressure sensor 32 is located on the lower pressure side than the pressure detection range of the pressure sensor 33. Here, the flow of the fluid to be measured changes from viscous flow to molecular flow as the pressure becomes lower. And the ease of flow of the fluid to be measured decreases as it changes from viscous flow to molecular flow. Therefore, the lower the pressure sensor is configured to detect the pressure of the low-pressure fluid to be measured, that is, the more the pressure detection range is on the lower pressure side, the lower the response speed (the longer the period). Further, when the plate-shaped baffle 36 and the porous baffle 37 are placed with respect to the same pressure sensor, the porous baffle 37 has a longer length of the flow path through which the fluid to be measured flows, so the response speed is slower accordingly. In the present embodiment, since the plate-shaped baffle 36 with a relatively fast response speed is arranged for the pressure sensor 32 on the low-pressure side with a relatively slow response speed, and the porous baffle 37 with a relatively slow response speed is arranged for the pressure sensor 33 on the high-pressure side with a relatively fast response speed, the difference in response speed between the pressure sensors 32 and 33 is reduced. Incidentally, the distance between the pressure-receiving diaphragm and the baffle (the space capacity between them) also affects the response speed. Specifically, the longer the distance, the lower the response speed. Therefore, the difference in response speed may be adjusted by the distance D1 (FIG. 4) between the plate-shaped baffle 36 and the pressure-receiving diaphragm 32CA and the distance D2 (FIG. 4) between the porous baffle 37 and the pressure-receiving diaphragm 33CA. For example, when D1 = D2 and the response speed of the pressure sensor 32 on the low-pressure side is still slow, D1 < D2 may be set. When D1 = D2 and the response speed of the pressure sensor 32 on the low-pressure side reverses the response speed of the pressure sensor 33, D2 < D1 may be set.

[0060] Furthermore, when pressure control is performed to approach a vacuum state, such as in semiconductor manufacturing equipment, and pressure measurement is performed by the sensor device 10, pressure fluctuations tend to occur during the transient state of pressure control at pressures that fall within the pressure detection range of the high-pressure pressure sensor 33 from the perspective of normal control operation. Therefore, if a high-speed response of pressure measurement to pressure fluctuations during the transient state of pressure control is prioritized over the difference in response speed mentioned above, it is preferable to use the plate-shaped baffle 36 on the high-pressure pressure sensor 33 side and the porous baffle 37 on the low-pressure pressure sensor 32 side to further increase the response speed of the pressure sensor 33 side.

[0061] As described above, the sensor device 10 according to this embodiment comprises a sensor head 30 and a pressure sensing pipe 40. The sensor head 30 includes a pressure sensing pipe 31 extending in the left-right direction (first direction) and pressure sensors 32 and 33 fixed to both the left and right ends of the pressure sensing pipe 31 (one end in the left-right direction and the other end different from this end (in this case, the opposite end)). The pressure sensing pipe 40 extends in the up-down direction (second direction) perpendicular to the left-right direction and is connected to the middle of the pressure sensing pipe 31, and guides the pressure of the fluid to be measured to the pressure sensors 32 and 33 via the pressure sensing pipe 31. The pressure sensor 32 includes a pressure-receiving diaphragm 32CA that receives the pressure of the fluid to be measured, and detects the pressure by converting the pressure received by the pressure-receiving diaphragm 32CA into an electrical signal. Furthermore, the pressure sensor 33 includes a pressure-receiving diaphragm 33CA that receives the pressure of the fluid to be measured, and detects the pressure by converting the pressure received by the pressure-receiving diaphragm 33CA into an electrical signal. The sensor head 30 further includes a plate-shaped baffle 36 and a porous baffle 37. The plate-shaped baffle 36 is positioned inside the pressure-sensing pipe 31 and faces the pressure-receiving diaphragm 32CA, and reduces the first accumulation amount, which is the amount of foreign matter accumulated on the pressure-receiving diaphragm 32CA, by contact with the fluid to be measured that flows from the pressure-sensing pipe 40 into the pressure-sensing pipe 31 and heads toward the pressure-receiving diaphragm 32CA. The porous baffle 37 is positioned inside the pressure-sensing pipe 31 and faces the pressure-receiving diaphragm 33CA, and reduces the second accumulation amount, which is the amount of foreign matter accumulated on the pressure-receiving diaphragm 33CA, by contact with the fluid to be measured that flows from the pressure-sensing pipe 40 into the pressure-sensing pipe 31 and heads toward the pressure-receiving diaphragm 33CA. Furthermore, the porous baffle 37 is shaped to reduce the second deposit amount by a larger amount than the reduction in the first deposit amount by the plate-shaped baffle 36.

[0062] With the above configuration, since a plate-shaped baffle 36 and a porous baffle 37 are employed, the rate of foreign matter accumulation can be made different between the two pressure-receiving diaphragms 32CA and 33CA. Furthermore, this enables the diagnosis of pressure measurement deterioration on the pressure sensor 32 side and adjustment of the response speed. Thus, this embodiment provides high added value to the sensor device 10.

[0063] The two types of baffles used in the sensor device 10 can be any type of baffle, as long as they are configured to cause different rates of foreign matter accumulation on the two opposing pressure-receiving diaphragms. For example, one of the two types of baffles may be plate-shaped, as in the plate-shaped baffle 36 described above, and the other baffle may be a porous baffle 37, comprising a plate-shaped portion (37A) facing the pressure-receiving diaphragm (33CA) and a cylindrical portion (37B) extending from the annular peripheral edge (37AB) of the plate-shaped portion in the opposite direction to the pressure-receiving diaphragm. The cylindrical portion may be configured to have multiple through-holes (especially a number of minute through-holes such as through-hole 37H) that allow the fluid to be measured to flow from the internal space of the cylindrical portion to the outer peripheral space (R22) and reach the pressure sensor 33. Furthermore, each of the multiple through-holes may be formed in a fine meandering shape as described above, so as to cause the fluid to be measured to meander. This makes it easier to deactivate the fluid being measured. Furthermore, although the specific shape is arbitrary, it is preferable to form the other baffle in a shape that deactivates the fluid being measured more easily than the other baffle. This makes it possible to make the amount of reduction in foreign matter accumulation different between the two pressure-receiving diaphragms.

[0064] Furthermore, the sensor device 10 includes a calculation circuit 95. The calculation circuit 95 derives the pressure received by the pressure-receiving diaphragm 32CA as the first pressure based on the electrical signal (pressure detection signal) from the pressure sensor 32, and derives the pressure received by the pressure-receiving diaphragm 33CA as the second pressure based on the electrical signal (pressure detection signal) from the pressure sensor 33. The pressure detection range of the pressure sensor 32 and the pressure detection range of the pressure sensor 33 include an overlapping range where they overlap. The pressure detection range of the pressure sensor 32 and the pressure detection range of the pressure sensor 33 may completely match, rather than partially, in order to ensure redundancy of the pressure sensors. When the second pressure is within the overlapping range, the calculation circuit 95 determines whether the first pressure and the second pressure are different, and if it determines that they are different, it outputs information indicating that a large amount of foreign matter has accumulated on the pressure-receiving diaphragm 32CA. This makes it possible to diagnose deterioration in pressure measurement on the pressure sensor 32 side.

[0065] The pressure detection range of pressure sensor 32 may be located on the lower pressure side or the higher pressure side than the pressure detection range of pressure sensor 33. The former reduces the difference in response speed between pressure sensors 32 and 33 to pressure fluctuations of the fluid being measured. The latter allows for pressure measurement that quickly follows pressure fluctuations on the high-pressure side. One of the pressure detection ranges, the high-pressure side or the low-pressure side, may have a wider range than the other, and this one may encompass the entirety of the other. This also ensures redundancy.

[0066] The positions of baffles 36 and 37 can be changed, but as shown in Figure 4, the plate-shaped baffle 36 is preferably positioned inside the pressure sensing pipe 31 on the side of the pressure sensor 32 (i.e., to the right) of the pressure sensing pipe 40. Furthermore, the porous baffle 37 is also preferably positioned inside the pressure sensing pipe 31 on the side of the pressure sensor 33 (i.e., to the right) of the pressure sensing pipe 40. This shortens the distances D1 and D2 and also provides the following effect: Each fluid to be measured, which flows in from the pressure sensing pipe 40 and is divided into left and right portions in the pressure sensing pipe 31, can strike baffles 36 and 37 from a direction perpendicular to baffles 36 and 37 (left and right direction) or a direction close to that direction. This makes it easier for foreign matter contained in the fluid to be measured to accumulate on baffles 36 and 37, and reduces the amount of foreign matter that accumulates on the pressure receiving diaphragms 32CA and 33CA.

[0067] The housing members 32AC and 33AC of the pressure sensors 32 and 33 may be considered as part of the pressure sensing pipe 31, and these housing members 32AC and 33AC may support the baffles 36 and 37. In this case, the pressure sensors 32 and 33 do not have the pressure chambers R12 and R22 to be measured, and these are considered to be provided in the pressure sensing pipe 31.

[0068] The present invention has been described above with reference to embodiments and modifications, but the present invention is not limited to the above embodiments and modifications. The shapes of each of the above elements can be changed as appropriate. Furthermore, 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 within a non-contradictory range.

[0069] (Note) A configuration based on the above embodiment and its modifications is described below as an example. (Note 1) A sensor head including a first pipe extending in a first direction, a first pressure sensor fixed to a first end of the first pipe, and a second pressure sensor fixed to a second end of the first pipe different from the first end, The system includes a second pipe that extends in a second direction different from the first direction and is connected to the first pipe midway, and which guides the pressure of the fluid to be measured to the first pressure sensor and the second pressure sensor via the first pipe, The first pressure sensor includes a first pressure-receiving diaphragm that receives the pressure of the fluid to be measured, and converts the pressure received by the first pressure-receiving diaphragm into a first electrical signal. The second pressure sensor includes a second pressure-receiving diaphragm that receives the pressure of the fluid to be measured, and converts the pressure received by the second pressure-receiving diaphragm into a second electrical signal. The aforementioned sensor head is A first baffle is positioned inside the first pipe, facing the first pressure-receiving diaphragm, and reduces the first accumulation amount, which is the amount of foreign matter accumulated on the first pressure-receiving diaphragm, by contact with the fluid to be measured that flows from the second pipe into the first pipe and heads toward the first pressure-receiving diaphragm. A second baffle is disposed inside the first pipe, facing the second pressure-receiving diaphragm, and reduces the second accumulation amount, which is the amount of foreign matter accumulated on the second pressure-receiving diaphragm, by contact with the fluid to be measured that flows from the second pipe into the first pipe and toward the second pressure-receiving diaphragm, and the second baffle is formed in a shape that reduces the second accumulation amount by a larger amount than the reduction amount of the first accumulation amount by the first baffle, further comprising: Sensor device. (Note 2) The system further includes a calculation circuit that derives the pressure received by the first pressure-receiving diaphragm as the first pressure based on the first electrical signal, and derives the pressure received by the second pressure-receiving diaphragm as the second pressure based on the second electrical signal. The first pressure detection range of the first pressure sensor and the second pressure detection range of the second pressure sensor include overlapping ranges that overlap with each other. The calculation circuit, when the second pressure is within the overlapping range, determines whether the first pressure and the second pressure are different, and if it determines that the first pressure and the second pressure are different, outputs information indicating that the first deposit amount is large. The sensor device described in Appendix 1. (Note 3) The first pressure detection range of the first pressure sensor is located on the lower pressure side than the second pressure detection range of the second pressure sensor. The sensor device described in Appendix 1 or 2. (Note 4) The first pressure detection range of the first pressure sensor is located on the higher pressure side than the second pressure detection range of the second pressure sensor. The sensor device described in Appendix 1 or 2. (Note 5) At least one of the first pressure detection range of the first pressure sensor and the second pressure detection range of the second pressure sensor is a range that encompasses the entirety of the other. A sensor device as described in any of the appendices 1 to 4. (Note 6) The second baffle is formed in a shape that is more likely to deactivate the fluid being measured than the first baffle. A sensor device as described in any of the appendices 1 to 5. (Note 7) The first baffle is plate-shaped, The second baffle comprises a plate-shaped portion facing the second pressure-receiving diaphragm and a cylindrical portion extending from the annular peripheral edge of the plate-shaped portion in the direction opposite to the second pressure-receiving diaphragm. The cylindrical portion has a plurality of through holes that allow the fluid to be measured to flow from the internal space of the cylindrical portion to the outer space, thereby reaching the second pressure sensor. Each of the plurality of through holes is formed in a fine meandering shape, and is shaped to cause the fluid to be measured to meander. A sensor device as described in any of the appendices 1 to 6. [Explanation of Symbols]

[0070] 10...Sensor device, 20...Sensor unit, 30...Sensor head, 31...Pressure sensing pipe, 31A,31B...Annular surface, 32...Pressure sensor, 32A...Housing, 32AA,32AB...Housing member, 32AC...Housing member, 32B...Support diaphragm, 32C...Sensor element, 32CA...Pressure receiving diaphragm, 32D...Conductive pin, 32E...Spring contact, 32F...Sealing member, 33...Pressure sensor, 33A...Housing, 33AA~33AC...Housing member, 33B...Support diaphragm, 33C...Sensor element, 33CA...Pressure receiving diaphragm, 33D...Conductive pin, 33E...Spring contact, 33F...Sealing member, 34,35...Insulator, 36...Plate baffle, 36A...Baffle body, 36B...Protruding part, 37...Porous baffle, 37A...First plate-shaped part, 37A A...Central part, 37AB...Annular peripheral part, 37B...Cylindrical part, 37C...Second plate-shaped part, 37CA...Through hole, 37H...Through hole (space), 37Z...Plate-shaped member, 37ZA...Protrusion, 40...Pressure sensing pipe, 41...Joint, 50...Heater, 50A...Opening, 51,52...Heater body, 53,54...Support member, 60...Fixing mechanism, 61,62...Boss, 63,64...Screw, 70...Insulation member, 71...Insulation material 72...Support member, 72A...Through hole, 73...Support member, 74,75...Insulation material, 75A...Through hole, 80...Bracket, 81,82...Bracket member, 90...Control unit, 91...Housing, 95...Calculation circuit, A1,A2,A3...Arrow, D1,D2...Distance, H1...Through hole, R11...Reference pressure chamber, R12...Measured pressure chamber, R21...Reference pressure chamber, R22...Measured pressure chamber, S...Temperature sensor.

Claims

1. A sensor head including a first pipe extending in a first direction, a first pressure sensor fixed to a first end of the first pipe, and a second pressure sensor fixed to a second end of the first pipe different from the first end, The system includes a second pipe that extends in a second direction different from the first direction and is connected to the first pipe midway, and which guides the pressure of the fluid to be measured to the first pressure sensor and the second pressure sensor via the first pipe, The first pressure sensor includes a first pressure-receiving diaphragm that receives the pressure of the fluid to be measured, and converts the pressure received by the first pressure-receiving diaphragm into a first electrical signal. The second pressure sensor includes a second pressure-receiving diaphragm that receives the pressure of the fluid to be measured, and converts the pressure received by the second pressure-receiving diaphragm into a second electrical signal. The aforementioned sensor head is A first baffle is positioned inside the first pipe, facing the first pressure-receiving diaphragm, and reduces the first accumulation amount, which is the amount of foreign matter accumulated on the first pressure-receiving diaphragm, by contact with the fluid to be measured that flows from the second pipe into the first pipe and heads toward the first pressure-receiving diaphragm. A second baffle is disposed inside the first pipe, facing the second pressure-receiving diaphragm, and reduces the second accumulation amount, which is the amount of foreign matter accumulated on the second pressure-receiving diaphragm, by contact with the fluid to be measured that flows from the second pipe into the first pipe and toward the second pressure-receiving diaphragm, and the second baffle is formed in a shape that reduces the second accumulation amount by a larger amount than the reduction amount of the first accumulation amount by the first baffle, further comprising: Sensor device.

2. The system further includes a calculation circuit that derives the pressure received by the first pressure-receiving diaphragm as the first pressure based on the first electrical signal, and derives the pressure received by the second pressure-receiving diaphragm as the second pressure based on the second electrical signal. The first pressure detection range of the first pressure sensor and the second pressure detection range of the second pressure sensor include overlapping ranges that overlap with each other. The calculation circuit determines whether the first pressure and the second pressure are different when the second pressure is within the overlapping range, and if it determines that the first pressure and the second pressure are different, it outputs information indicating that the first deposit amount is large. The sensor device according to claim 1.

3. The first pressure detection range of the first pressure sensor is located on the lower pressure side than the second pressure detection range of the second pressure sensor. The sensor device according to claim 1.

4. The first pressure detection range of the first pressure sensor is located on the higher pressure side than the second pressure detection range of the second pressure sensor. The sensor device according to claim 1.

5. At least one of the first pressure detection range of the first pressure sensor and the second pressure detection range of the second pressure sensor is a range that encompasses the entirety of the other. The sensor device according to claim 1.

6. The second baffle is formed in a shape that is more likely to deactivate the fluid being measured than the first baffle. The sensor device according to claim 1.

7. The first baffle is plate-shaped, The second baffle comprises a plate-shaped portion facing the second pressure-receiving diaphragm and a cylindrical portion extending from the annular peripheral edge of the plate-shaped portion in the direction opposite to the second pressure-receiving diaphragm. The cylindrical portion has a plurality of through holes that allow the fluid to be measured to flow from the internal space of the cylindrical portion to the outer space, thereby reaching the second pressure sensor. Each of the plurality of through holes is formed in a fine meandering shape, and is shaped to cause the fluid to be measured to meander. The sensor device according to claim 1.

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