JP2017009348A - Flow sensor - Google Patents

Abstract

A flow sensor is provided which is not easily affected by changes in ambient temperature.
SOLUTION: A housing 1 and a measurement piping section 3 disposed in the housing 1 and fixed to the housing 1 via elastic members 2A and 2B and having lower thermal elasticity than the housing 1 are provided. And a sensor chip 8 for detecting the flow rate of the fluid flowing through the measurement piping unit 3.
[Selection] Figure 1

Description

  The present invention relates to measurement technology, and more particularly to a flow sensor.

  Flow sensors that measure the flow rate of fluid are used in various situations. For example, in a medical field, a flow sensor is used to monitor a flow rate of a fluid such as a chemical solution or blood flowing in a catheter or an infusion tube. Further, in the semiconductor device manufacturing site, a flow sensor is used to monitor the flow rate of a fluid such as a solvent flowing in the tube. In the flow sensor, it has been proposed to arrange a semiconductor module including a heat source and a temperature sensor on an outer surface of a pipe through which a fluid flows (see, for example, Patent Document 1).

Special table 2003-532099 gazette

  An object is to provide a flow sensor that is less susceptible to changes in ambient temperature.

  According to an aspect of the present invention, (a) a housing, and (b) a measurement pipe that is disposed inside the housing and is fixed to the housing via an elastic member, and has low thermal elasticity compared to the housing. And a sensor chip that detects the flow rate of the fluid that flows in the measurement piping section.

  The flow sensor may further include a joint connected to the measurement piping unit, and the joint may be fixed to the housing via an elastic member. The joint includes a body part connected to the measurement pipe part, and a fixing part to be fitted to the outer periphery of the body part. The body part penetrates the end surface of the housing, and the fixing part fitted to the body part is an elastic member. It may be fixed to the end face of the housing via A thread may be provided on the outer periphery of the body portion of the joint, and the fixing portion of the joint may be a nut.

  Alternatively, the above flow sensor may further include a joint connected to the measurement pipe section and a joint holding section that holds the joint, and the joint holding section may be fixed to the housing via the elastic member. The joint holding part has an end surface through which the joint penetrates, the housing has a side surface that is parallel to the measurement pipe part, and the end surface of the joint holding part is fixed to the end part of the side surface of the housing through an elastic member. May be. A hook-shaped portion may be provided at an end portion of the side surface of the housing, and an end surface of the joint holding portion may be fixed to the hook-shaped portion at the end portion of the side surface of the housing via an elastic member.

  In the above flow sensor, the elastic member may include an elastic adhesive. The elastic adhesive may comprise silicone or fluorine. Alternatively, the elastic member may include a gasket. The gasket may be an O-ring.

  Alternatively, the flow sensor may further include a joint connected to the measurement pipe section, and the expansion / contraction member may be an expansion pipe section connected to the measurement pipe section provided in the joint. Furthermore, the telescopic pipe part may be a bellows.

  In the above flow sensor, the housing may be made of resin. The measurement piping part may be made of glass, metal, or resin.

  According to the present invention, it is possible to provide a flow sensor that is not easily affected by ambient temperature changes.

It is a typical sectional view of a flow sensor concerning a 1st embodiment of the present invention. It is a typical perspective view of a sensor chip of a flow sensor concerning a 1st embodiment of the present invention. It is typical sectional drawing of the sensor chip of the flow sensor which concerns on the 1st Embodiment of this invention seen from the III-III direction of FIG. It is a typical sectional view of a measurement piping part of a flow sensor concerning a 1st embodiment of the present invention. It is a typical sectional view of a modification of a flow sensor concerning a 1st embodiment of the present invention. It is a typical sectional view of a flow sensor concerning a 2nd embodiment of the present invention. It is a typical perspective view of the joint holding part of the flow sensor concerning a 2nd embodiment of the present invention. It is a typical perspective view of the housing | casing of the flow sensor which concerns on the 2nd Embodiment of this invention. It is a typical perspective view of the combination of the joint holding part and housing | casing of the flow sensor which concerns on the 2nd Embodiment of this invention. It is a typical sectional view of a flow sensor concerning a modification of a 2nd embodiment of the present invention. It is a typical sectional view of a flow sensor concerning a 3rd embodiment of the present invention. It is a typical sectional view of a flow sensor concerning a modification of a 3rd embodiment of the present invention.

  Embodiments of the present invention will be described below. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, the drawings are schematic. Therefore, specific dimensions and the like should be determined in light of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

(First embodiment)
As shown in FIG. 1, the flow sensor according to the first embodiment includes a housing 1, a housing disposed inside the housing 1, and fixed to the housing 1 via the elastic members 2 </ b> A and 2 </ b> B. And a sensor chip 8 that detects the flow rate of the fluid flowing through the measurement pipe unit 3.

  The shape of the housing 1 is a pillar body such as a prism or a cylinder. Although the material of the housing | casing 1 is resin, for example, it will not be limited if thermal expansion / contraction (thermal expansion coefficient) is higher than the measurement piping part 3. FIG. A through hole is provided in the end surfaces 11 </ b> A and 11 </ b> B of the housing 1 facing the end of the measurement piping unit 3. The housing 1 protects the measurement piping unit 3 and the sensor chip 8 arranged inside.

  The material of the measurement pipe section 3 through which the fluid to be measured for flow rate flows is, for example, a metal such as glass or stainless steel, and a resin such as polyetheretherketone (PEEK). If (thermal expansion coefficient) is low, it will not be limited. For example, when the material of the measurement pipe part 3 is glass, the thermal conductivity is good, and therefore, temperature distribution measurement in the measurement pipe part 3 by the sensor chip 8 described later becomes easy.

  A joint 5 </ b> A that connects the measurement piping section 3 inside the housing 1 and the tube 6 </ b> A outside the housing 1 is inserted into the through hole of the end surface 11 </ b> A of the housing 1. The joint 5A includes a body portion 51A as a male screw provided with a thread on the outer periphery, and a fixing portion 52A as a female screw fitted to the body portion 51A. A nut or the like can be used as the fixing portion 52A.

  A joint 5B that connects the measurement piping portion 3 inside the housing 1 and the tube 6B outside the housing 1 is inserted into the through hole of the end surface 11B of the housing 1. The joint 5B includes a body portion 51B as a male screw provided with a thread on the outer periphery, and a fixing portion 52B as a female screw fitted to the body portion 51A. A nut or the like can be used as the fixing portion 52B.

  The tubes 6A and 6B are flexible tubes such as Teflon tubes, but are not particularly limited.

  For example, the fluid that has flowed through the tube 6A flows through the measurement piping portion 3 connected to the body portion 51A of the joint 5A through the through hole of the body portion 51A of the joint 5A connected to the tube 6A. The tube 6B connected to the body part 51B of the joint 5B flows through the through hole of the body part 51B of the joint 5B connected to the part 3.

  The outer diameter of the fixing portion 52A of the joint 5A is larger than the through hole provided in the end surface 11A of the housing 1, and the outer diameter of the fixing portion 52B of the joint 5B is the through hole provided in the end surface 11B of the housing 1. Bigger than. Therefore, the fixing parts 52A and 52B fastened to the body parts 51A and 51B of the joints 5A and 5B connected to the measurement pipe part 3 restrict the movement of the measurement pipe part 3 with respect to the housing 1.

  The fixing portion 52A of the joint 5A is fixed to the outer surface of the end surface 11A of the housing 1 via the elastic member 2A. Further, the fixing portion 52B of the joint 5B is fixed to the outer surface of the end surface 11B of the housing 1 via the elastic member 2B.

  The elastic members 2A and 2B are, for example, rubber-like elastic bodies, and are cured products of elastic adhesives. As the elastic adhesive, for example, a silicone-based adhesive or a fluorine-based adhesive can be used. The elastic member 2A is formed, for example, by tightening the fixing portion 52A to the vicinity of the end surface 11A of the housing 1 and hanging an elastic adhesive in the gap between the side surface of the fixing portion 52A and the end surface 11A of the housing 1. The elastic member 2B is formed, for example, by tightening the fixing portion 52B to the vicinity of the end surface 11B of the housing 1 and hanging an elastic adhesive in the gap between the side surface of the fixing portion 52B and the end surface 11B of the housing 1. The Young's modulus of the elastic members 2A and 2B is, for example, about 2 to about 5 MPa.

  As shown in FIG. 2 which is a perspective view and FIG. 3 which is a cross-sectional view seen from the III-III direction, the sensor chip 8 covers the cavity 66 on the substrate 60 on which the cavity 66 is provided. The insulating film 65 arranged and the heater 61 provided on the insulating film 65 are provided. Further, the sensor chip 8 is located on the upstream side of the measurement pipe section 3 shown in FIG. 1 with respect to the heater 61, the upstream side resistance temperature measuring element 62 shown in FIG. 2 and FIG. A temperature resistance element 63 and an ambient temperature sensor 64 provided on the upstream side of the upstream temperature measurement resistance element 62 are provided.

  The heater 61, the upstream temperature measuring resistance element 62, the downstream temperature measuring resistance element 63, and the ambient temperature sensor 64 are in thermal contact with the outer wall of the measurement piping section 3 shown in FIG. As shown in FIG. 4, which is a cross-sectional view as viewed from the longitudinal direction of the measurement piping unit 3, it contacts the upstream temperature measurement resistance element 62, the downstream temperature measurement resistance element 63, and the ambient temperature sensor 64. The part to do may be flat.

  A portion of the insulating film 65 shown in FIG. 3 that covers the cavity 66 forms a heat insulating diaphragm. The ambient temperature sensor 64 measures the temperature of the measurement piping unit 3 shown in FIG. The heater 61 shown in FIGS. 2 and 3 is disposed at the center of the insulating film 65 covering the cavity 66, and heats the measurement pipe section 3 so that the temperature is higher than the temperature measured by the ambient temperature sensor 64. . The upstream temperature measuring resistance element 62 is used for detecting the temperature upstream of the heater 61, and the downstream temperature measuring resistance element 63 is used for detecting the temperature downstream of the heater 61.

  Here, when the fluid in the measurement piping section 3 shown in FIG. 1 is stationary, the heat applied by the heater 61 shown in FIGS. 2 and 3 diffuses symmetrically in the upstream direction and the downstream direction. Accordingly, the temperatures of the upstream resistance temperature element 62 and the downstream resistance temperature element 63 are equal, and the electrical resistances of the upstream resistance temperature element 62 and the downstream resistance temperature element 63 are equal. On the other hand, when the fluid in the measurement piping section 3 shown in FIG. 1 flows from upstream to downstream, the heat applied by the heater 61 shown in FIGS. 2 and 3 is carried in the downstream direction. Therefore, the temperature of the downstream side resistance thermometer element 63 becomes higher than the temperature of the upstream side resistance thermometer element 62. Therefore, there is a difference between the electrical resistance of the upstream side resistance thermometer element 62 and the electrical resistance of the downstream side resistance thermometer element 63. The difference between the electrical resistance of the downstream resistance temperature element 63 and the electrical resistance of the upstream temperature resistance element 62 has a correlation with the flow velocity of the fluid in the measurement pipe section 3 shown in FIG. Therefore, the flow rate of the fluid flowing through the measurement pipe section 3 shown in FIG. 1 is obtained from the difference between the electrical resistance of the downstream resistance temperature element 63 and the upstream resistance resistance element 62 shown in FIGS. .

As a material of the substrate 60 shown in FIGS. 2 and 3, silicon (Si) or the like can be used. As a material of the insulating film 65, silicon oxide (SiO ₂ ) or the like can be used. The cavity 66 is formed by anisotropic etching or the like. Further, platinum (Pt) or the like can be used as the material of the heater 61, the upstream temperature measuring resistance element 62, the downstream temperature measuring resistance element 63, and the ambient temperature sensor 64, and can be formed by a lithography method or the like. .

  In the flow sensor according to the first embodiment described above, the thermal expansion / contraction of the measurement piping unit 3 is lower than that of the housing 1 shown in FIG. The thermal expansion can be larger than that of the measurement pipe portion 3. Therefore, if the measurement pipe part 3 is temporarily fixed inside the housing 1 without using the elastic members 2A and 2B, stress is generated in the fixed part due to the difference in thermal expansion and contraction, and in some cases, deformation or breakage occurs. May occur, and impurities may enter the inside of the housing 1 or lead to a decrease in pressure resistance of the joint. On the other hand, according to the flow sensor according to the first embodiment, the elastic members 2A and 2B can suppress the stress that may be caused by the difference in thermal elasticity between the casing 1 and the measurement piping unit 3. Become.

  1 shows an example in which the fixing portions 52A and 52B of the joints 5A and 5B are arranged on the outside of the housing 1, but as shown in FIG. The fixing parts 52A and 52B may be arranged. In this case, the fixing portion 52A of the joint 5A is fixed to the inner surface of the end surface 11A of the housing 1 via the elastic member 2A. Further, the fixing portion 52B of the joint 5B is fixed to the inner surface of the end surface 11B of the housing 1 via the elastic member 2B.

  1 and 5 may be gaskets such as O-rings, for example. In this case, for example, the expansion members 2A and 2B, which are gaskets, are first brought into contact with the end surfaces 11A and 11B of the housing 1, respectively, and then the fixing portions 52A and 52B are disposed so as to sandwich the expansion members 2A and 2B. You may clamp | tighten to the vicinity of end surface 11A, 11B.

(Second Embodiment)
As shown in FIGS. 6 to 8, the flow sensor according to the second embodiment includes a casing 101 having side surfaces 104A and 104B, and a casing 101 disposed inside the casing 101, and the casings via the elastic members 12A and 12B. The measurement piping part 3 fixed to the body 101 and having low thermal elasticity as compared with the casing 101 and the sensor chip 8 for detecting the flow rate of the fluid flowing in the measurement piping part 3 are provided.

  The flow sensor according to the second embodiment further includes a joint holding part 110 including end faces 111A and 111B that hold the joints 5A and 5B connected to the measurement pipe part 3, and the joint holding part 110 is shown in FIG. As shown in FIG. 4, the casing 101 is fixed via the elastic members 12A and 12B.

  As shown in FIG. 7, the joint holding part 110 includes a rectangular bottom surface 112 and end faces 111A and 111B provided with openings through which the joints 5A and 5B pass. The end surfaces 111 </ b> A and 111 </ b> B are disposed perpendicular to the bottom surface 112 on both short sides of the bottom surface 112, for example. The end surfaces 111A and 111B may be slidable with respect to the bottom surface 112.

  As shown in FIG. 8, the housing 101 includes a rectangular upper surface 103 and side surfaces 104A and 104B. For example, the side surfaces 104 </ b> A and 104 </ b> B are connected to both long sides of the upper surface 103 perpendicularly to the upper surface 103. The side surfaces 104A and 104B are parallel to the measurement piping unit 3 shown in FIG.

  As illustrated in FIG. 9, the joint holding unit 110 and the housing 101 are combined so that the bottom surface 112 of the joint holding unit 110 and the top surface 103 of the housing 101 face each other. Here, as shown in FIG. 6, the end surfaces 111A and 111B of the joint holding portion 110 are fixed to the end portions of the side surfaces 104A and 104B of the housing 101 via the elastic members 12A and 12B.

  The flanges 102A and 102B are provided at the ends of the side surfaces 104A and 104B of the housing 101, and the end surfaces 111A and 111B of the joint holding unit 110 are connected to the side surfaces 104A and 104B of the housing 101 via the elastic members 12A and 12B. It may be fixed to the hook-shaped portions 102A and 102B at the ends of the two.

  Other components of the flow sensor according to the second embodiment are the same as those of the first embodiment. Also with the flow sensor according to the second embodiment, the elastic members 12A and 12B can suppress the stress that may be caused by the difference in thermal elasticity between the housing 1 and the measurement piping unit 3.

  In FIG. 6, the inner sides of the opposing end surfaces 111A and 111B of the joint holding portion 110 and the outer sides of the hook-shaped portions 102A and 102B at the end portions of the side surfaces 104A and 104B of the housing 101 connect the elastic members 12A and 12B. The example fixed via is shown. On the other hand, as shown in FIG. 10, the outer sides of the opposing end surfaces 111A and 111B of the joint holding portion 110 and the inner sides of the flanges 102A and 102B at the end portions of the side surfaces 104A and 104B of the housing 101 are expanded and contracted. It may be fixed via the members 12A and 12B.

(Third embodiment)
As shown in FIG. 11, the flow sensor according to the third embodiment includes a housing 1, a housing disposed inside the housing 1, and fixed to the housing 1 via the elastic members 200 </ b> A and 200 </ b> B. And a sensor chip 8 that detects the flow rate of the fluid flowing through the measurement pipe unit 3.

  In the third embodiment, the expansion members 200A and 200B are expansion pipe portions such as bellows connected to the measurement pipe portion 3 provided in the joints 5A and 5B. Other components of the flow sensor according to the third embodiment are the same as those of the first embodiment. Also with the flow sensor according to the third embodiment, the elastic members 200A and 200B can suppress the stress that may be caused by the difference in thermal elasticity between the casing 1 and the measurement piping unit 3.

  In FIG. 11, an example in which the fixing portion 52A of the joint 5A is fixed to the outer surface of the end surface 11A of the housing 1 and the fixing portion 52B of the joint 5B is fixed to the outer surface of the end surface 11B of the housing 1 is shown. Indicated. On the other hand, as shown in FIG. 12, the fixed portion 52A of the joint 5A is fixed to the inner surface of the end surface 11A of the housing 1, and the fixed portion 52B of the joint 5B is fixed to the inner surface of the end surface 11B of the housing 1. It may be fixed.

(Other embodiments)
As mentioned above, although this invention was described by embodiment, it should not be understood that the description and drawing which form a part of this indication limit this invention. From this disclosure, various alternative embodiments, embodiments, and operation techniques should be apparent to those skilled in the art. For example, if the temperature range of the measurement piping unit 3 is known, the ambient temperature sensor 64 shown in FIGS. 2 and 3 may be omitted. Thus, it should be understood that the present invention includes various embodiments and the like not described herein.

DESCRIPTION OF SYMBOLS 1,101 Housing | casing 2A, 2B, 12A, 12B, 200A, 200B Elastic member 3 Measuring piping part 5A, 5B Joint 6A, 6B Tube 8 Sensor chip 11A, 11B End surface 51A, 51B Body part 52A, 52B Fixed part 60 Substrate 61 Heater 62 Upstream temperature measuring resistor element 63 Downstream temperature measuring resistor element 64 Ambient temperature sensor 65 Insulating film 66 Cavity 102A, 102B Cone-shaped part 103 Upper surface 104A, 104B Side surface 110 Joint holding part 111A, 111B End surface 112 Bottom surface

Claims (13)

A housing,
A measurement piping section that is disposed inside the housing and is fixed to the housing via an elastic member, and has low thermal elasticity compared to the housing,
A sensor chip for detecting the flow rate of the fluid flowing in the measurement pipe section;
A flow sensor. It further comprises a joint connected to the measurement pipe section,
The joint is fixed to the housing via the elastic member;
The flow sensor according to claim 1. The joint is
A body part connected to the measurement pipe part, a fixing part fitting with the outer periphery of the body part,
With
The body portion penetrates the end face of the housing;
The fixing portion fitted to the body portion is fixed to an end surface of the housing via the elastic member.
The flow sensor according to claim 2.   The flow sensor according to claim 3, wherein a thread is provided on an outer periphery of the body portion, and the fixing portion is a nut. A joint connected to the measurement pipe section;
A joint holding part for holding the joint, and
The joint holding part is fixed to the housing via the elastic member;
The flow sensor according to claim 1. The joint holding portion includes an end surface through which the joint passes,
The housing includes a side surface that is parallel to the measurement pipe section,
An end surface of the joint holding portion is fixed to an end portion of the side surface of the housing via the elastic member.
The flow sensor according to claim 5. A hook-shaped portion is provided at an end of the side surface of the housing,
An end surface of the joint holding portion is fixed to a hook-shaped portion at an end portion of the side surface of the housing via the elastic member.
The flow sensor according to claim 6.   The flow sensor according to claim 1, wherein the elastic member includes an elastic adhesive.   The flow sensor of claim 8, wherein the elastic adhesive comprises silicone or fluorine.   The flow sensor according to claim 1, wherein the elastic member includes a gasket.   The flow sensor according to claim 10, wherein the gasket is an O-ring. It further comprises a joint connected to the measurement pipe section,
The expansion / contraction member is an expansion / contraction pipe connected to the measurement pipe provided in the joint,
The flow sensor according to claim 1.   The flow sensor according to claim 12, wherein the telescopic pipe portion is a bellows.