JP2010107477A - Temperature sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a contact type temperature sensor of high precision and responsibility, reduced in configuration space. <P>SOLUTION: The temperature sensor is provided with: a protection pipe 2 wherein a tip part with one end closed is protruded or contacted by surface to a piping through a sensor insert hole A penetrating a pipe wall of the piping 11, to form a space with the end face of the sensor insert hole, because of reduced wall thickness at a central pipe portion; a temperature detection element 1 which is fitted in the internal space at the tip part of the protection pipe, with a connection wire 7 from itself being taken out of an opening B at the rear end of the protection pipe; an O ring 3 provided in press-contacted manner between the protection pipe 2 and the sensor insert hole A; and a fixing plate 5 which fixes the protection pipe to the piping by pressurizing the rear end part after the protection pipe 2 is inserted from the rear end part of the sensor insert hole A. The outer peripheral surface of the protection pipe other than the surface contacting with a fluid in the piping is insulated by the outside air of the protection pipe, piping, O ring, and fixing plate. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a temperature sensor that measures the temperature of a fluid by inserting it into a fluid pipe through which a liquid or gas flows, and particularly relates to a temperature sensor in which a contact-type temperature detection element has a metal protective tube.

  The temperature sensor of the object to be measured includes a contact type and a non-contact type, and the contact type includes a temperature detection element such as a resistance temperature detector, a thermocouple, a thermistor, or an IC temperature sensor.

  In a temperature sensor including such a contact-type temperature detection element, a metal protective tube is generally used to protect the temperature detection element from an object to be measured.

  A temperature sensor 20 having a conventional protection tube as shown in FIG. 5 includes a temperature detection element 1, a cylindrical metal protection tube 12 in which the temperature detection element 1 is housed at the tip, and the protection tube 12. An insertion space 12a that extends in the axial direction of the tube and a signal line 17 that is inserted through the insertion space 12a and that is provided on the rear end side of the protective tube 12 and connects the temperature detection element 1 and a signal processing unit (not shown). Has been.

  Furthermore, the protective tube 12 is configured by a fixing plate 15 and a fixing screw 16 for inserting the protective tube 12 into a piping 11 or the like for flowing an object to be measured and fixing the protective tube 12 to the outer wall of the piping 11.

  The contact-type temperature sensor 20 having the metal protective tube 12 is attached so as not to be affected by the temperature of the pipe 11 passing through the protective tube 12 or the outside world in order to accurately measure the temperature of the object to be measured. Therefore, it is recommended that the insertion length L inside the pipe 11 is such that L ≧ 15 × D to 20 × D when the diameter of the protective tube 12 is D (for example, non-patent document). 1).

  In addition to accuracy, responsiveness to temperature changes may be important for the functions required of the temperature sensor 20, and the tip portion is made thin to improve responsiveness and strength against temperature changes. A tube is disclosed. (For example, refer to Patent Document 1).

  Further, the temperature detection apparatus includes a temperature sensor held in a housing such as a pipe and having a measurement range protruding from an end of the pipe, and is in an opening of a hollow body (including a fluid or gaseous medium). There is a temperature sensor for fluid detection comprising means for fixing one end.

In detail, a temperature sensor for a fluid in the hollow space of the pipe, in particular a flowing fluid or gaseous medium, which can be connected to the evaluation device via the plug-in device, In a temperature sensor arranged with a connecting member firmly inserted into a protective cylinder, the protective tube projects into an opening of a housing hollow space sealed at least at the tip with an elastic O-ring with respect to the external atmosphere. A detection element is arranged on one end of the circuit board extending in the longitudinal direction in the region of the tip of the protective tube, and is connected to an insertion device located at the opposite end of the circuit board via a conductive path. The device is surrounded by a collet (annular body) that is tightly coupled with the protective tube of the sensor housing, the collet comprising a screw that projects into the hollow space housing for fixing purposes In addition, there is a fluid temperature output sensor characterized in that the collet has a flange extending in the radial direction, and the flange provides a sealing O-ring as a pressing surface against the opening of the hollow space housing (for example, (See Patent Document 2).
Japanese Patent No. 3062429 JP 2002-48654 A (Incorporated Association) Japan Electric Measuring Instruments Manufacturers Association, "How to Use Thermometers Correctly", Nippon Kogyo Publishing, June 18, 1990, page 177

  The temperature sensor disclosed in Patent Document 1 is an improved temperature responsiveness by reducing the thickness of the tip of the protective tube, but the insertion length may be increased to make it less susceptible to the influence of piping and outside air. Necessary, there is a problem that the fluid flow is stagnant and the components of the fluid are likely to adhere.

  In the temperature sensor disclosed in Patent Document 2, the temperature detection element is disposed on one end of a circuit board extending in the longitudinal direction in the region of the tip of the protective tube, and is opposite to the circuit board via a conductive path. The insertion device is coupled to the insertion device positioned in the section, and the insertion device is surrounded by a collet (annular body) firmly connected to the protective tube of the sensor housing, and is therefore highly resistant to vibration.

  However, the structure disclosed in Patent Document 2 is configured such that the collet portion of the sensor housing and the pipe are integrally adhered, and the protective tube that houses the temperature detection sensor on the circuit board is smaller than the collet portion. Therefore, the temperature of the fluid in the piping is easily conducted to the piping with a low thermal resistance, and therefore the temperature of the fluid is affected by the outside air and the temperature of the piping, so that the temperature of the fluid is accurate and the temperature detection element is heated at high speed. There is a problem that is not conducted.

  The present invention has been made to solve the above-described conventional problems, and is small in size and highly responsive, hardly affecting the flow of fluid, being hardly affected by the temperature of the outside air and piping. An object is to provide a contact-type temperature sensor.

  In order to achieve the above object, a temperature sensor according to claim 1 of the present invention is a contact-type temperature sensor that is inserted into a pipe through which a fluid in a liquid or gas state flows and measures the temperature of the fluid. From the sensor insertion hole penetrating the pipe wall of the pipe, a tip end portion closed at one end protrudes or comes into contact with the pipe, and the thickness of the central cylinder portion is reduced to provide a space between the sensor insertion hole end face The protective tube and the inner space of the tip of the protective tube are filled with a heat conductive adhesive or magnesium oxide (MgO), and the end thereof is fixed with an epoxy resin, and a connecting wire from itself is attached. The temperature detecting element taken out from the opening at the rear end of the protective tube, an O-ring provided in pressure contact between the protective tube and the sensor insertion hole, and the protective tube, the piping of the sensor insertion hole Insert from the outer wall side of the A fixing plate that presses the rear end of the protective tube to fix the protective tube to the pipe, and the outer peripheral surface of the protective tube other than being in contact with the fluid in the pipe is connected to the outside air of the protective tube and the Insulating the pipe from the O-ring and the fixing plate so that heat conducted from the fluid to the temperature detection element is less affected by outside air and the pipe and is quickly transferred. To do.

  In order to achieve the above object, a temperature sensor according to claim 1 of the present invention is a contact-type temperature sensor that is inserted into a pipe through which a fluid in a liquid or gas state flows and measures the temperature of the fluid. From the sensor insertion hole that penetrates the pipe wall of the pipe, the protective tube in which the end portion closed at one end protrudes or is in contact with the pipe, and the heat conductive adhesive in the internal space of the tip portion of the protective pipe, Alternatively, the temperature detecting element that is filled with magnesium oxide (MgO) and the end thereof is fixed with an epoxy resin, and the connecting wire from itself is taken out from the opening at the rear end of the protective tube, the protective tube, and the sensor Insert the O-ring provided in pressure contact with the insertion hole and the protective tube from the outer wall side of the pipe of the sensor insertion hole, and press the rear end of the protective tube to attach the protective tube to the With a fixing plate The front end of the protective tube has a convex shape with a predetermined curvature, the protective tube cylinder is provided with a flange, and the outer periphery of the flange is filled with the O-ring having a diameter equal to or greater than the thickness of the flange. And the outer periphery of the protective tube are opposed to two insulating cylinders provided with a flange, sandwich the flange from both directions of the sensor insertion hole, press the fixing plate from the rear end of the protective tube, and Is insulated from the outside air and the piping, the rear end is pressed by the fixing plate to seal the sensor insertion hole, and the outer peripheral surface of the protective tube other than the surface contacting the fluid in the piping is The heat transmitted from the fluid to the temperature detection element is insulated from the outside air of the protective tube and the piping by the O-ring and the fixing plate, and is quickly affected by the outside air and the piping. It is characterized by doing so.

  As described above, according to the present invention, there is provided a contact-type temperature sensor that is less affected by the flow of fluid and less affected by the temperature of the outside air and piping and that is small and has good responsiveness. Can do.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a configuration diagram of a temperature sensor 10 according to the first embodiment. FIG. 1A shows a temperature sensor 10 that is inserted and attached from the outer wall side to a sensor insertion hole A that penetrates the pipe wall of the pipe 11 through which the object to be measured flows, and FIG. 11 is a detailed cross-sectional view of the temperature sensor 10 as viewed from the tube axis direction xx ′.

  The object to be measured flowing through the pipe 11 may be, for example, a liquid flowing through a pipe in a manufacturing process such as milk or juice in the food industry, or a gas flowing through a pipe such as a gas in a chemical plant. . Moreover, it does not necessarily flow, and may flow in a container or the like.

  The temperature sensor uses a contact-type temperature detection element such as a platinum resistance thermometer, thermistor, thermocouple, IC temperature sensor, etc. that are provided in close contact with the protective tube. The target is one that is inserted in or receives a temperature-sensitive surface from the object to be measured and receives the heat to measure the temperature of the fluid.

  An optimum temperature detection element is determined in advance depending on the temperature measurement range of the object to be measured.

  Here, the case where temperature measurement of the fluid flowing in the piping 11 provided in the manufacturing process of the food industry is performed as an object to be measured will be described as an example.

  In FIG. 1 (b), the tip of the one end closed protrudes or comes into contact with the pipe 11 from the sensor insertion hole A penetrating the pipe wall of the metal pipe 11 made of stainless steel or the like, and the thickness of the central cylinder portion is reduced. Then, a protective tube 2 made of metal such as stainless steel that forms a space between the end surface of the sensor insertion hole, and an epoxy-based high thermal conductive adhesive or magnesium oxide (MgO) in the inner space at the tip of the protective tube 2 ), The end portion thereof is fixed with an epoxy resin, and the temperature detecting element 1 for taking out the connecting wire 7 from itself from the opening B at the rear end portion of the protective tube 2, the protective tube 2 and the sensor insertion hole A The O-ring 3 made of silicon rubber or the like provided in pressure contact with the protective tube 2 and the protective tube 2 are inserted from the outer wall side of the pipe 11 of the sensor insertion hole A, and the rear end portion of the protective tube 2 is pressed. A fixing plate 5 for fixing the protective tube 2 to the piping 11; Et al made.

  The inner surface of the sensor insertion hole A and the outer surface of the protective tube 2 sandwich a spacer 4 made of an insulator such as Teflon (registered trademark), and fix the fixing plate 5 to the pipe 11 with screws 6.

  Further, the tip of the protective tube 2 has a convex shape with a predetermined curvature so that the fluid component does not adhere and the stagnation does not occur in the fluid flow. An O-ring 3 is inserted between the skirt and the pipe 11, and the rear end of the protective pipe 2 and the sensor insertion hole A are composed of an insulator 4 formed of Teflon (registered trademark) or the like and a fixing plate 5 having a predetermined strength. And is pressed from the rear end of the protective tube 2 and sealed in the sensor insertion hole A.

  The spacer 4 and the fixing plate 5 may be formed of an insulator such as plastic having a predetermined strength, and the spacer 4 and the fixing plate 5 may be integrated.

  Further, the space between the temperature detecting element 1 and the protective tube 2 is fixed with a high heat conductive adhesive to improve heat transfer.

  The temperature sensor configured in this way and inserted from the outer wall of the pipe 11 is attached to the outer peripheral surface of the protective pipe 2 other than the surface where the fluid in the pipe 11 is in contact with the outside air of the protective pipe 2 and the pipe 11 and the O-ring 3. Insulating and insulating with the spacer 4 or the fixing plate 5, the heat conducted from the fluid to the temperature detecting element 1 is hardly affected by the outside air and the piping 11, and quickly transfers the temperature of the fluid. be able to.

  Therefore, it is possible to provide a temperature sensor that is less likely to cause stagnation in the fluid flow, is small, has a good temperature responsiveness, and can measure the fluid temperature with high accuracy.

  FIG. 2 is a configuration diagram of the temperature sensor 10 according to the second embodiment. FIG. 2A is a diagram illustrating a sensor insertion hole A penetrating the pipe wall of the pipe 11 through which the object to be measured flows. FIG. 2B shows the details of the temperature sensor 10 in a cross-sectional view.

  2 that are the same as those in the first embodiment shown in FIG. 1 are denoted by the same reference numerals, and the description thereof is omitted.

  The second embodiment is different from the first embodiment in that the shape of the protective tube 2 in FIG. 1 is a structure that protrudes from the pipe 11, but the protective tube 2a shown in FIG. The shape of the surface is matched with the shape of the inner wall of the pipe 11 so that the protruding portion is pressed, and the entire temperature sensing surface of the temperature detecting element 1 is close to be provided at a distance of the thickness of the protective tube. It is in.

  That is, the front end portion of the protective tube 2a has a curved shape matching the curved inner wall surface of the pipe 11, the O-ring 3 is inserted between the front end skirt and the pipe 11, the rear end portion of the protective tube 2a and the sensor insertion hole. The sensor insertion hole A is sealed by insulating the space A from the rear end portion of the protective tube 2a by insulating the spacer 4 and the fixing plate 5 from each other.

  Therefore, it is difficult for stagnation to occur in the fluid flowing in the pipe 11, and a structure in which the temperature of the fluid is easily transferred to the temperature detection element 1 quickly and easily is possible.

  FIG. 3 is a configuration diagram of the temperature sensor 10 according to the third embodiment. FIG. 3A is a diagram illustrating a sensor insertion hole A that passes through the tube wall of the pipe 11 through which the object to be measured flows, and is inserted from the tube outer wall side. FIG. 3B shows the details of the temperature sensor 10 in a cross-sectional view as seen from the tube axis direction xx ′.

  3 that are the same as those in the first embodiment shown in FIG. 1 are denoted by the same reference numerals, and the description thereof is omitted.

  The third embodiment is different from the first embodiment in that the shape of the protective tube 2 in FIG. 1 is a structure protruding from the pipe 11, and the spacer 4 is interposed between the sensor insertion hole A and the fixing plate 5. 4, the protective tube 2c shown in FIG. 4 is formed so that the protective tube 2c has an umbrella shape and is inserted from the inside of the pipe 11, and is screwed from the outside of the partial pipe 11 of the umbrella handle. It is in the point made.

  Specifically, the protective tube 2c has an umbrella shape with a T-shaped cross section, the shape of the upper umbrella portion is a curved shape along the inner wall surface of the tube wall, the central portion of the handle is hollow, and The outer periphery of the bottom part is a screw part, an insulating plate 14a is sandwiched between the umbrella part and the inner wall, an O-ring 13a is inserted around the neck of the umbrella part, and the protective tube 2c is connected to the inner side of the sensor insertion hole A. The fixing plate 5 was pressed from the outer wall side of the pipe 11 and the screw portion was tightened with the spring washer 8a and the nut 8 to seal the sensor insertion hole A.

  Accordingly, the heat receiving area of the umbrella portion of the protective tube 2c is large, and the temperature of the fluid can be averaged to transfer heat to the temperature detecting element 1a. Therefore, temperature measurement that is not easily affected by variations in measurement locations can be performed.

  FIG. 4 is a configuration diagram of the temperature sensor 10 according to the fourth embodiment. FIG. 4A is a diagram illustrating a sensor insertion hole A penetrating the pipe wall of the pipe 11 through which the object to be measured is passed. FIG. 4B shows details of the temperature sensor 10 in a cross-sectional view as seen from the tube axis direction xx ′.

  4 that are the same as those in the first embodiment shown in FIG. 1 are denoted by the same reference numerals, and description thereof is omitted.

  The fourth embodiment is different from the first embodiment in that the shape of the protective tube 2 in FIG. 1 is that the spacer 4 is inserted between the sensor insertion hole A and the fixing plate 5 from the outer wall side of the sensor insertion hole A. The protective tube 2b shown in FIG. 4 is provided with a flange on the protective tube 2b, and the spacers 4a and 4b are fitted into the sensor insertion hole A from both sides of the sensor insertion hole A between the sensor insertion hole A and the fixing plate 5a. The O-ring 3a is disposed on the outer periphery of the flange, and the O-ring 3a is pressed by the fixing plate 5a.

  In the first embodiment, the thickness of the central tube portion is reduced to form a space between the end surface of the sensor insertion hole A. However, the space around the tube portion of the protective tube 2b and the end surface of the sensor insertion hole are spacers 4a, 4b. It is closely attached and does not form a space.

  That is, the front end portion of the protective tube 2b has a convex shape with a predetermined curvature, the protective tube tube portion is provided with a flange, and the outer periphery of the flange is filled with an O-ring 3a having a diameter equal to or greater than the thickness of the flange. And the outer periphery of the protective tube 2b, the two insulating cylinders provided with the flanges are opposed to each other, the flanges are sandwiched from both directions of the sensor insertion hole A, and the fixing plate 5a is pressed from the rear end of the protective tube 2b. 2b was insulated from the outside air and the piping 11, and the rear end portion was pressed by the fixing plate 5a to seal the sensor insertion hole A.

  Accordingly, the spacer 4a is attached to the outer periphery of the protective tube 2b in advance, press-fitted into the sensor insertion hole A, the O-ring 3a is attached, and the spacer 4b and the fixing plate 5a are pressed and attached from behind, so that the protective tube 2b A workability and a temperature sensor that is easy to assemble can be obtained.

  The present invention is not limited to the above-described embodiments, and may be any means that insulates and insulates the periphery of the protective tube other than the temperature sensing portion, and does not depart from the gist of the present invention. Various modifications can be made within the range.

The block diagram of Example 1 of the temperature sensor of this invention. The block diagram of Example 2 of the temperature sensor of this invention. The block diagram of Example 3 of the temperature sensor of this invention. The block diagram of Example 4 of the temperature sensor of this invention. The block diagram of the conventional temperature sensor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Temperature detection element 1a Thermal conductive adhesive 2, 2a, 2b, 2c, 12 Protective tube 3, 3a, 13a O-ring 4, 4a, 4b, 14a Spacer 5, 5a, 15 Fixing plate 6, 16 Fixing screw 7, 17 Connection line 8 Nut 8a Spring washer 10, 20 Temperature sensor 11 Piping

Claims (5)

A contact-type temperature sensor that is inserted into a pipe through which a fluid in a liquid or gas state flows and measures the temperature of the fluid,
From the sensor insertion hole penetrating the pipe wall of the pipe, a tip end closed at one end protrudes or comes into surface contact with the pipe, and the wall thickness is reduced between the sensor insertion hole end face by reducing the thickness of the central cylinder part. The protective tube to be formed;
A heat conductive adhesive or magnesium oxide (MgO) is filled in the inner space of the front end portion of the protective tube, and the end portion thereof is fixed with an epoxy resin. The temperature detecting element taken out from the opening;
An O-ring provided in pressure contact between the protective tube and the sensor insertion hole;
The protective tube is inserted from the outer wall side of the pipe of the sensor insertion hole, and includes a fixing plate that presses the rear end of the protective pipe and fixes the protective pipe to the pipe.
Insulate the outer peripheral surface of the protective tube other than the surface in contact with the fluid in the piping by the O-ring and the fixing plate from the outside air of the protective tube and the piping,
A temperature sensor characterized in that heat conducted from the fluid to the temperature detection element is less affected by outside air and the piping and is transferred quickly.   The front end of the protective tube has a convex shape with a predetermined curvature, and the O-ring is inserted between the bottom of the convex surface of the front end and the pipe, and between the rear end of the protective tube and the sensor insertion hole. The temperature sensor according to claim 1, wherein the fixing plate is insulated and the rear end portion is pressed by the fixing plate to seal the sensor insertion hole.   The front end of the protective tube has a curved shape matching the curved inner wall surface of the pipe, the O-ring is inserted between the bottom of the curved surface of the front end and the pipe, and the rear end of the protective tube and the sensor are inserted. 2. The temperature sensor according to claim 1, wherein a gap between the holes is insulated by the fixing plate, and the rear end portion is pressed by the fixing plate to seal the sensor insertion hole. The protective tube is an umbrella shape having a T-shaped cross section, the shape of the upper umbrella portion is a curved shape along the inner wall surface of the tube wall, the central portion of the handle of the umbrella is hollow, and The outer periphery of the bottom is a screw part,
An insulating plate is sandwiched between the umbrella part and the inner wall, and the O-ring is inserted around the neck of the umbrella part,
The protection tube is inserted from the inner wall side of the sensor insertion hole, the fixing plate is pressed from the outer wall side of the pipe, and the screw portion is tightened with a nut to seal the sensor insertion hole. The temperature sensor according to 1. A contact-type temperature sensor that is inserted into a pipe through which a fluid in a liquid or gas state flows and measures the temperature of the fluid,
From the sensor insertion hole that penetrates the pipe wall of the pipe, the protective pipe projecting or contacting the tip of the one end closed into the pipe;
A heat conductive adhesive or magnesium oxide (MgO) is filled in the inner space of the front end portion of the protective tube, and the end portion thereof is fixed with an epoxy resin. The temperature detecting element taken out from the opening;
An O-ring provided in pressure contact between the protective tube and the sensor insertion hole;
The protective tube is inserted from the outer wall side of the pipe of the sensor insertion hole, and includes a fixing plate that presses the rear end of the protective pipe and fixes the protective pipe to the pipe.
The distal end portion of the protective tube has a convex shape with a predetermined curvature, the protective tube tube portion is provided with a flange, the outer periphery of the flange is filled with the O-ring having a diameter greater than the thickness of the flange, and the O-ring The outer periphery of the protective tube is opposed to two insulating cylinders provided with flanges, the flange is sandwiched from both directions of the sensor insertion hole, the fixing plate is pressed from the rear end of the protective tube, and the protective tube is Insulate from outside air and the pipe, press the rear end portion with the fixing plate to seal the sensor insertion hole,
Insulate the outer peripheral surface of the protective tube other than being in contact with the fluid in the piping from the outside air of the protective tube and the piping with the O-ring and the fixing plate,
A temperature sensor characterized in that heat conducted from the fluid to the temperature detection element is not easily affected by outside air or the piping and is transferred quickly.

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