JP2003042856A - Temperature detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a temperature detector whose constitution is compact and which is superior in versatility, by a method wherein a sure heat conduction property to a shape memory alloy coil spring from an object to-be-temperature-detected can be always maintained irrespective of an ambient environment or its temperature change. SOLUTION: The temperature detector is provided with a tube body 1 which receives heat from the object 21 to-be-temperature-detected, the shape memory alloy coil spring 8 which is housed inside the tube body 1 so as to maintain a stored shape in a prescribed temperature range, a heat-conductive spring fixture 2 which comprises a trunk 3 having an outer circumferential face coming into contact with the inner surface of the tube body 1 and a screw thread part 4 screwed to one end of the coil spring 8 so as to hold it, a movable member 11 which comprises a screw thread part 13 screwed to the other end of the coil spring 8 so as to hold it in one end and which is arranged to be movable inside the tube body 1 to its axis center line, a display part 18 which is attached to the other end of the movable member 11 and which protrudes or retreats with reference to the tube body 1, and a bias spring 20 by which a spring force received by the movable body 11 due to the holding force of the stored shape of the coil spring 8 and a spring force in the opposite direction are added to the movable member 11. In the tube body 1, a part facing at least the fixture 2 and the outer circumference of the coil spring 8 in a shape stored state is formed of a heat-conductive material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a temperature detector used for, for example, detecting a decrease in the temperature of a steam pipe due to a malfunction of a steam trap attached to the steam pipe and performing a visible abnormality display. It is a thing.

[0002]

2. Description of the Related Art For example, when an operation failure occurs in a steam trap due to performance deterioration or failure, the condensate water accumulates excessively and the temperature of the steam pipe lowers. Therefore, conventionally, a temperature detector has been devised which simply detects the temperature of the steam pipe and visually displays whether the device is normal or abnormal based on the detected temperature. As this temperature detector, there is one that sets an approximate detection temperature by the memory shape of the coil spring made of shape memory alloy, and when the temperature detection target such as steam piping falls below the detection temperature, a visible warning It is designed to display and is used in many industrial fields. Examples of such a temperature detector include a pipe temperature display device disclosed in Japanese Patent Laid-Open No. 10-62267 (hereinafter referred to as a first prior art), and a drain discharge device operation disclosed in Utility Model Registration No. 2531859. An indicator (hereinafter referred to as a second conventional technology) and an operation indicator for a drain discharge device (hereinafter referred to as a third conventional technology) disclosed in Japanese Utility Model Registration No. 2531860 are known.

In the first prior art described above, a coil spring made of a shape memory alloy is wound around the outer circumference of a steam pipe of a temperature detection object, one end of which is fixed to the steam pipe, and the other end of the coil spring is attached. The movable ring is extrapolated so that it can move in the longitudinal direction of the steam pipe,
The biasing spring biases the movable ring in the direction in which the coil spring contracts, and the base end is engaged with the movable ring by the pointer.
Displays the temperature of the pipe according to the position of the movable ring. Thereby, the temperature of the pipe can be visually confirmed by the indicated value of the pointer.

In the second conventional technique, the upper end of a coil spring made of a shape memory alloy is fixed to a pin suspended in an outer cylinder attached to a steam pipe of a temperature detection object, and the lower end of the coil spring is fixed. The weight is suspended and the coil spring is expanded or contracted depending on the temperature of the outer cylinder, so that the weight is exposed to the outside of the outer cylinder or housed in the outer cylinder. With this, it is possible to see at a glance whether or not the steam pipe is at a predetermined temperature depending on whether or not the weight is exposed from the outer cylinder.

In the third conventional technique, the upper end of a coil spring made of a shape memory alloy is fixed to the upper part of the inner surface of an outer cylinder attached to the steam pipe of the temperature detection object, and the lower end of the coil spring is rotatable. The lever is connected between the fulcrum and the weight at one end, and the other end of the lever is connected to a marker movable in the marker guide along the outer cylinder via a connecting rod. Thereby, it is possible to visually recognize whether or not the steam pipe is at the predetermined temperature depending on whether or not the marker is exposed from the marker guide.

[0006]

However, in the first prior art, since the coil spring made of a shape memory alloy is wound directly around the outer circumference of the steam pipe, the temperature-detected body is a cylinder like the steam pipe. In addition to being limited to the body, the diameter and length of the coil spring need to be changed according to the difference in the diameter or length of the steam pipe, so that it cannot be a general-purpose temperature detector. Also, the shape memory alloy coil spring is exposed to the outside air when it is installed outdoors, so even when the cold air in the winter is received, the temperature of the steam pipe is higher than the set value. However, the temperature of the coil spring may fall below the set value, causing malfunction. Therefore, in general, as a means for preventing wasteful heat dissipation of the steam pipe, it is often done to wind a belt-shaped heat insulating material around the steam piping to shield it from the outside air, but when the exposed coil spring is covered with the heat insulating material. Since the heat insulating material presses the coil spring, there is a problem that the operation of the coil spring is hindered. Further, a movable part is provided between the coil spring wound around the outer circumference of the steam pipe and the bias spring so as to be movable in the longitudinal direction of the steam pipe, and the movable part is rotatably attached to the display part. Since the base end of the pointer needs to be engaged, the mounting work is troublesome.

On the other hand, in the second prior art, since the weight is used instead of the bias spring in the first prior art, vertical installation is a condition, and the installation direction and size of the applicable equipment such as the steam trap are large. Depending on the size, the range of use may be limited, but the shape and dimensions of the outer cylinder and the coil spring made of shape memory alloy can be standardized regardless of the size of the steam trap, making it a general-purpose temperature detector. Has the advantage of being compactly summarized.

On the other hand, the shape memory alloy coil spring is attached with its upper end hooked on a thin pin hung on the peripheral wall of the outer cylinder. Therefore, the heat receiving means of the coil spring is radiant heat from the outer cylinder. It is necessary to hermetically seal the inside of the outer cylinder as a basic configuration because there is no choice but to rely only on this. Even with such a configuration, since the heat transfer to the coil spring is poor only by radiation, the temperature followability of the shape memory alloy coil spring with respect to the temperature change of the outer cylinder remains a problem, and the coil spring is A considerable amount of time elapses before reacting to the temperature change, and a change in the shape of the coil spring with respect to the temperature of the outer cylinder tends to be deviated, resulting in low temperature detection sensitivity. Further, the third conventional technique also has substantially the same problem as the above-described second conventional technique.

The present invention has been made in view of the conventional problems described above, and it is possible to always maintain a reliable heat transfer from the temperature-detected body to the coil spring made of a shape memory alloy regardless of the outside air environment and its temperature change. The purpose of the present invention is to provide a temperature detector having a compact structure and excellent versatility.

[0010]

In order to achieve the above object, a temperature detector according to one aspect of the present invention includes a cylindrical body which comes into contact with a temperature-detected body to receive heat, and a cylindrical body which is housed in the cylindrical body. A coil spring made of a shape memory alloy that retains a memorized shape in a predetermined temperature range, a body having an outer peripheral surface that is fixed in contact with the inner surface of the tubular body, and one end of the coil spring screwed together. A heat-conducting spring fixture having a screw portion that holds one end portion, and a screw portion that is screwed to the other end portion of the coil spring and holds the other end portion at one end portion, and in the tubular body A movable member disposed so as to be movable in the axial direction, and a display unit attached to the other end of the movable member for displaying by protruding outward or immersing inward with respect to the cylindrical body. ,
A bias spring for applying to the movable member a spring force in a direction opposite to the spring force received by the movable member by the stored holding force of the coil spring, and the tubular body includes at least the spring fixture and the shape. The portion facing the outer circumference of the coil spring in the memory state is formed of a heat conductive material.

In this temperature detector, heat is transferred from the object to be detected to the coil spring made of a shape memory alloy through the cylindrical body, the body of the spring fixture and the screw part by heat conduction, and the temperature of the object to be detected is constant. When a range, for example, a certain value or more is held, the coil spring that receives heat from this temperature-detecting body by heat conduction also maintains a predetermined temperature range, for example, a shape memory temperature or higher, and a previously stored shape (for example, contraction). The shape is maintained and the movable member is pulled by the shape retaining force of the coil spring against the spring force of the bias spring, and the display unit is housed in the cylinder. If the object to be detected is out of a certain range, for example, if it falls below a certain temperature, the temperature of the coil spring becomes
Since the holding force of the memory shape cannot be maintained outside the predetermined temperature range, the bias spring overcomes the spring force of the coil spring and moves the movable member in the direction away from the coil spring. Accordingly, the display unit attached to the movable member projects or retracts from the cylindrical body and visually displays that the temperature detection target is out of the constant temperature range.

Further, in this temperature detector, the outer peripheral surface of the body of the spring fixture comes into contact with the inner surface of the cylindrical body which comes into contact with the temperature-detected body to receive heat, and is fixed at a relative position where a large heat-receiving area is secured. Furthermore, since one end of the coil spring is screwed into the screw part of the spring fixture, the one end is stable compared to the case where the coil spring is simply wound around an annular groove having a smooth circumferential surface. Since the contact area, that is, the heat receiving area is increased, the heat received by the tubular body from the temperature detection target is efficiently transferred to the coil spring by heat conduction. In addition, since the coil spring also receives heat by radiant heat from the inner surface of the cylindrical body, the coil spring reacts accurately and quickly when the temperature detection target temperature falls below or above the detection temperature, and changes its shape. Further, since the coil spring is housed in the cylinder, it is not easily affected by the temperature change of the outside air even when installed outdoors. Furthermore, each component is configured to be housed in a cylinder, and when mounting, it is only necessary to perform a simple work of fixing the cylinder by bringing the cylinder into contact with the temperature detection target, so that it is versatile. It can be used as a simple temperature detector. Further, the tubular body can be made compact by standardizing the shape and the dimension regardless of the shape and the dimension of the temperature detection object.

In a preferred embodiment of the invention,
The spring fixture is provided with a guide portion that is inserted into the hollow portion of the coil spring and restricts the radial movement of the coil spring. As a result, the coil spring is prevented from coming into strong contact with the inner surface of the tubular body during the contracting operation and operates smoothly, and the coil spring is arranged as close to the inner surface of the tubular body as possible. Thus, the radiant heat from the inner surface of the tubular body can be efficiently received by the coil spring. The gap between the inner surface of the cylindrical body and the outer peripheral portion of the coil spring is preferably 0.5 to 2.0 mm. The gap is 0.
If it is less than 5 mm, the coil spring may strongly contact the inner surface of the tubular body, and if it exceeds 2.0 mm, it becomes difficult for the coil spring to efficiently receive radiant heat from the inner surface of the tubular body.

In another preferred embodiment of the present invention, the movable member is further fixed to the inner surface of the cylindrical body, the movable member is movably inserted in the axial direction, and one end of the bias spring is supported. Equipped with a bias support.
Since the bias spring supports the bias spring and the movable member and stabilizes the position, the spring force of the bias spring is set to a required value so that the coil spring is out of the predetermined temperature range and the shape holding force (spring When the force is lost, the movable member can be reliably moved by the spring force of the bias spring.

In another preferred embodiment of the present invention, a spring pressing tool for pressing the coil spring against the threaded portion of at least one of the spring fixing tool and the movable member from the outside in the radial direction is further provided. . As a result, the coil spring is brought into close contact with the screw portion to increase the contact area, heat is efficiently transferred from the screw portion to the coil spring by heat conduction, and the coil spring is prevented from coming off from the screw portion when contracting. It is possible to reliably prevent the movable member from moving smoothly.

[0016]

Preferred embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a vertical sectional view showing a temperature detector TD according to an embodiment of the present invention. In the figure, a cylindrical body 1 which is an outer case of the temperature detector TD is formed in a cylindrical shape by aluminum, which is a material having heat conductivity, that is, high thermal conductivity,
The outer surface of the temperature detection target (not shown) is fixedly attached in such a manner that its outer surface is in direct contact with the temperature detection target and receives heat from the temperature detection target. At the one end side (the left end side in the figure) of this tubular body 1, the tubular body 1
Similarly, a spring fixture 2 made of aluminum is fitted and fixed. The spring fixture 2 includes a body portion 3 having an outer peripheral surface to be crimped to the inner peripheral surface of the tubular body 1, and a screw portion 4 having a thread groove formed on the outer peripheral surface having a smaller diameter than the body portion 3.
And a guide portion 7 having a diameter smaller than that of the screw portion 4 and formed in a rod shape having a circular cross section.

The coil spring 8 made of a shape memory alloy has one end portion (the left end portion in the drawing) screwed into the threaded portion 4 of the spring fixture 2 to be locked, and the outer peripheral portion of the one end portion. Since the elastic force of the spring pressing tool 9 attached in the covering arrangement is applied from the outside in the radial direction, the spring pressing tool 9 is pressed against and held by the screw portion 4. That is, the spring pressing tool 9
As shown in the front view and the right side view of FIGS. 2A and 2B, a rectangular metal plate is curved in an arc shape having an inner diameter slightly smaller than the outer diameter of the coil spring 8 to have a C-shape. It was formed. Further, as shown in FIG. 4, which is an enlarged view of a part of FIG. 1, the coil spring 8 has a diameter slightly larger than the height of the screw thread 4 a having a trapezoidal cross section of the screw portion 4 and has a diameter larger than that of the screw thread 4.
It is fitted into the thread groove 4b in a state of slightly protruding from a. The spring pressing tool 9 is slightly elastically deformed to the expanded diameter state and externally fitted to the coil spring 8, so that the spring pressing tool 9 is pressed against the outer peripheral portion of the coil spring 8 protruding from the screw thread 4a by the restoring force due to the deformation, and The spring 8 is pressed against the thread groove 4b so as not to separate.

A bias support 10 is fixed to the inner peripheral surface of the cylindrical body 1 shown in FIG. 1 closer to the other end (right end in FIG. 1) than the central portion. This bias support 10 is shown in FIG.
As shown in the front view and the right side view of (b), it is a ring-shaped member having a relatively large thickness and having a side surface shape in which a cutout portion 10b is formed in a part of a circular shape. It has a slightly large outer diameter, and is deformed into a state in which the central hole 10a is slightly reduced in diameter and press-fitted into the cylindrical body 1, so that the restoring force due to the deformation causes the inner peripheral surface of the cylindrical body 1 to move. It is fixed by crimping.

A movable member 11 is housed in the tubular body 1 movably in the axial direction from the center portion to the other end portion (right end portion in FIG. 1) of the tubular body 1 shown in FIG. This movable member 1
Reference numeral 1 denotes a shaft portion 12 slidably inserted into a center hole 10a of a bias support 10 and a holding screw portion 13 continuously provided at one end portion (left end portion in FIG. 1) of the shaft portion 12.
And a mounting screw portion 14 projecting from the other end of the shaft portion 12 are integrally formed. In the holding screw portion 13,
The other end of the coil spring 8 is screwed and locked, and the elastic force of the spring pressing tool 17 attached so as to cover the outer peripheral portion of the coil spring 8 is applied to the coil spring 8 from the outside in the radial direction. Since the coil spring 8 is applied, the coil spring 8 is pressed against the screw portion 4 and held so as not to be separated. The structure and operation of the spring pressing tool 17 are the same as those of the spring pressing tool 9 on the screw portion 4 side of the spring fixing tool 2.

At the other end of the shaft portion 12 of the movable member 11, a cylindrical display portion 18 is screwed into a female screw portion 18a of the display screw portion 18 with a washer 19 interposed therebetween. It is lined up. The outer surface of the display unit 18 is
In this embodiment, it is colored red. A bias spring 20 formed of a compression coil spring is wound around the shaft portion 12 and interposed between the bias support body 10 and the display portion 18.

The shape memory temperature of the coil spring 8 (the limit temperature at which the memorized shape is exhibited) is, for example, 70 ° C. In this embodiment, it is shown in FIG. 1 in a predetermined temperature range of 70 ° C. or higher. In addition to maintaining the memorized shape in the contracted state, the spring force (holding force) for maintaining the memorized shape disappears and softens when the temperature falls outside a predetermined temperature range, for example, at a temperature of 60 ° C or less due to the influence of hysteresis. Become.

Next, the operation of the temperature detector TD will be described. For example, as shown in FIG. 5, the temperature detector TD is attached in parallel to the outer surface of the steam pipe 31 to which the steam trap 30 is attached and fixed by a metal band 32. At this time, the coil spring 8 in FIG. 1 is at approximately room temperature and the spring force for maintaining the memory shape has disappeared, so the movable member 11 receives the spring force of the bias spring 20 and is indicated by the arrow A in FIG. Moved in the direction,
The holding screw portion 13 is positioned at the position indicated by the chain double-dashed line in contact with the bias support 10, and the display portion 18 projects outside the cylinder 1 as indicated by the chain double-dashed line.

When the steam trap 30 to which the temperature detector TD is attached operates normally and the pipe 31 is kept at a certain temperature or higher, the pipe 31 to the barrel 1 and the body 3 of the spring fixture 2 are connected. The heat is transferred to the coil spring 8 via the screw portion 4 by heat conduction, and the radiant heat from the inner peripheral surface of the pipe 31 is transferred to the coil spring 8. As a result, when the coil spring 8 rises to a temperature of 70 ° C or higher,
The movable member 11 is moved to the position shown in FIG. 1 by pulling the movable member 11 against the spring force of the bias spring 20 due to the large shape-retaining force generated at the time of contraction while restoring the memorized shape of the contracted state. Pull it to the position where it is completely contained in 1. After that, when the steam trap 30 continues to operate normally and the temperature of the pipe 31 continues to be maintained above a certain value, the coil spring 8 continues to maintain the memorized shape of the contracted state. Is held in a state of being housed in.

When the steam trap 30 shown in FIG. 5 has a malfunction or malfunction such as a malfunction, the condensate water accumulates too much and the temperature of the pipe 31 falls below a certain value. When the temperature of the coil spring 8 in FIG. 1, which receives heat from the pipe 31, drops below 60 ° C., the holding force for maintaining the memory shape disappears and becomes soft. Therefore, the movable member 11 is moved by the spring force of the bias spring 20 to the position where the holding screw portion 13 contacts the bias support body 10, and the display portion 18 projects from the cylindrical body 1. Therefore, the operator visually recognizes that the display portion 18 whose outer peripheral surface is colored red protrudes from the cylinder body 1, and at a glance that the steam trap 30 is malfunctioning due to a functional deterioration or a failure. Can judge.

In this temperature detector TD, the contact area between the tubular body 1 and the body portion 3 and the contact between the screw portion 4 and the coil spring 8 in the heat transfer path from the tubular body 1 receiving the heat from the pipe 31 to the coil spring 8. All areas are set large. That is, in the spring fixture 2, the jig is pushed into the cross-shaped groove 3a of the body 3 to expand the body 3, and then the body 3 is press-fitted into the tubular body 1. The entire outer peripheral surface of the body portion 3 is in close contact with the inner peripheral surface of the cylindrical body 1 as a heat transfer surface by being attached. In addition, the thread groove 4 of the screw portion 4
As shown in FIG. 4, one end of the coil spring 8 fitted in b protrudes radially outward with a protrusion width p of about 0.1 mm with respect to the top surface of the screw thread 4a of the screw portion 4, and this protrusion The outer peripheral portion is pressed radially inward by the spring pressing tool 9.

Therefore, the cylindrical body 1 and the body portion 3, and the screw portion 4 and the one end portion of the coil spring 8 are in contact with each other with a relatively large contact area, and a high heat transfer property is secured.
Further, since the coil spring 8 is arranged such that the gap c between its outer peripheral portion and the inner surface of the cylindrical body 1 is close to about 0.5 to 2 mm, the radiant heat from the inner peripheral surface of the cylindrical body 1 is generated. The heat is efficiently transmitted to the coil spring 8 and a heat retaining effect is obtained by the radiant heat. As a result, the heat of the cylindrical body 1 is effectively and efficiently transmitted to the coil spring 8, and the temperature changes while accurately following the temperature of the cylindrical body 1. Moreover, since the coil spring 8 is housed in the tubular body 1, it is hardly affected by the temperature change of the outside air even when it is installed outdoors. Therefore, the temperature detector TD can accurately detect and display the malfunction of the steam trap 30 based on the temperature change of the pipe 31 of FIG. Also, the coil spring 8
When the cylindrical body 1 reaches a temperature corresponding to the shape memory temperature of the coil spring 8, it quickly restores the contracted state of the memory shape.

Further, in general, the coil spring 8 made of a shape memory alloy is less likely to receive heat evenly in its entirety at all times, and the expansion and contraction operation involves a meandering and complicated movement in relation to the movable member 11. It is easy to become. On the other hand, in the temperature detector TD, the guide portion 7 of the spring fixture 2 inserted in the hollow portion of the coil spring 8 regulates the coil spring 8 so as not to be displaced radially outward. As a result, the coil spring 8 smoothly expands and contracts along the longitudinal direction of the tubular body 1 even if partial temperature unevenness occurs due to uneven heat reception. Further, since the guide portion 7 suppresses the outward displacement in the radial direction during the expansion / contraction operation of the coil spring 8, the above-described coil spring 8 is placed close to the inner surface of the cylindrical body 1 in a small gap c. Easy to do. If there is no guide part 7,
When the coil spring 8 expands and contracts, the coil spring 8 meanders and comes into contact with the inner surface of the tubular body 1, and the friction during the contact easily causes a malfunction.
The guide portion 7 may have a length extending to a position where the holding screw portion 13 of the movable member 11 that moves when the coil spring 8 contracts does not come into contact.

Further, in the temperature detector TD, each constituent member is housed in the cylinder 1, and the cylinder 1 is brought into contact with a temperature detection object such as a steam pipe at the time of mounting. Since it is only necessary to fix it, it is possible to make the diameter and length of the cylindrical body 1 uniform regardless of the shape and size of the temperature detection target, and to use it as a general-purpose temperature detector. can do.

In the above embodiment, the case where the cylindrical body 1 and the spring fixture 2 are made of aluminum, which is a material having a high thermal conductivity, has been described. However, another metal having a high thermal conductivity, such as copper, is used. You may form. Further, even if the spring fixture 2 is formed by using brass whose thermal conductivity is slightly lower than that of aluminum or copper, the same effect as described above can be obtained. Furthermore, in the above-described embodiment, the tubular body 1 is an integral body, but for example, the spring fixture 2 in the tubular body 1 is used.
And a portion facing the outer periphery of the coil spring 8 in the shape memory state (contracted state in this example), that is, in this embodiment,
The screw portion 1 for holding the movable member 11 in the contracted state of the coil spring 8 from the mounting portion of the spring fixture 2 (the left end portion of the tubular body 1).
The part corresponding to the arrangement position of 3 is made of a material having a high thermal conductivity, the other part is made of a material having a low thermal conductivity such as heat resistant resin, and the two parts are joined to form a cylindrical body. It may be formed, and in that case, the effect of suppressing the heat radiation from the cylindrical body 1 is obtained. Furthermore, this temperature detector T
The means for attaching D to the temperature-detected body is not limited to the metal band 32 of the embodiment, but may be formed according to the shape of the temperature-detected body.
A leaf spring, a stopper with a magnet, or a heat resistant adhesive can be used.

Further, in the above-mentioned embodiment, the case where the display portion 18 is projected from the cylindrical body 1 to indicate the malfunction of the steam trap 30 when the coil spring 8 becomes below the shape memory temperature is exemplified. As the coil spring 8 made of a shape memory alloy, a coil spring 8 of a type that has a memory shape in an expanded state when the temperature becomes higher than the shape memory temperature is used. The display unit 18 is resisted against the spring force of the bias spring 20 composed of a tension spring.
May be projected to indicate that the steam trap 30 is operating normally. In that case, it is preferable that the outer peripheral surface of the display unit 18 is colored and displayed in blue.
By visually recognizing the blue display, it can be confirmed that the steam trap 30 is operating normally.

[0031]

As described above, according to the temperature detector of the present invention, the heat of the temperature detection object is efficiently transmitted to the coil spring, and the coil spring is also affected by the radiant heat from the inner wall of the cylindrical body. Since the coil spring receives the heat, the coil spring follows the temperature of the temperature-detected body, and reacts accurately and quickly to change its shape. Further, since the coil spring is housed in the cylinder, it is hardly affected by the temperature change of the outside air even when it is installed outdoors. Further, each component is configured to be housed in the cylinder, and when mounting, it is only necessary to perform a simple work of fixing the cylinder by bringing the cylinder into contact with the temperature detection target. The body can be made compact by standardizing the shape and dimensions regardless of the shape and dimensions of the temperature detection object, and can be used as a general-purpose temperature detector.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing a temperature detector according to an embodiment of the present invention.

2 (a) and 2 (b) are respectively a front view and a right side view showing a spring pressing tool in the temperature detector of the above.

3 (a) and 3 (b) are respectively a front view and a right side view showing a bias support in the temperature detector of the above.

FIG. 4 is an enlarged view of a part of FIG.

FIG. 5 is a front view showing a mounting state of the above temperature detector.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Cylindrical body, 2 ... Spring fixing tool, 3 ... Body part, 4 ... Spring fixing tool screw part, 7 ... Guide part, 8 ... Coil spring, 9, 17 ...
Spring pressing tool, 10 ... bias support, 11 ... movable member,
13 ... Retaining screw part (screw part of movable member), 18 ... Display part, 20 ... Bias spring, 31 ... Steam pipe (temperature detection object), TD ... Temperature detector.

Claims (5)

[Claims] 1. A cylindrical body that comes into contact with a temperature-detecting body to receive heat, a coil spring made of a shape memory alloy that is housed in the cylindrical body and holds a memory shape within a predetermined temperature range, and an inner surface of the cylindrical body. A heat-conducting spring fixture having a body portion having an outer peripheral surface that is fixed by contacting with the screw and a screw portion that is screwed into one end portion of the coil spring and holds the one end portion, and the other end of the coil spring. A movable member disposed at one end thereof so as to be screwed into the end portion and holding the other end thereof, the movable member being movably arranged in the axial direction of the tubular body, and attached to the other end portion of the movable member. And a display unit for displaying by protruding outward or immersing inward with respect to the cylindrical body, and a spring force applied to the movable member in a direction opposite to the spring force received by the holding force of the stored shape of the coil spring. A bias spring for applying a spring force to the movable member, A temperature detector in which at least a portion of the cylindrical body facing the outer circumference of the spring fixture and the coil spring in a shape memory state is formed of a heat conductive material. 2. The temperature detector according to claim 1, further comprising a guide portion, which is inserted into the hollow portion of the coil spring and restricts radial movement of the coil spring, in the spring fixture. . 3. The temperature detector according to claim 1, wherein the gap between the inner surface of the cylindrical body and the outer peripheral portion of the bias spring is set to 0.5 to 2.0 mm. 4. The bias member according to claim 1, wherein the movable member is fixed to an inner surface of the cylindrical body, the movable member is movably inserted in the axial direction, and one end of the bias spring is supported. Temperature detector with a biasing support. 5. The spring pressing device according to claim 1, further comprising a spring pressing device that presses the coil spring against a screw portion of at least one of the spring fixing device and the movable member from outside in a radial direction with elastic force. Temperature detector.