JP7321519B2 - contact thermometer - Google Patents

Description

Article 30, Paragraph 2 of the Patent Act applies Published in the leaflet of the temperature sensor with built-in magnet MG series issued on January 22, 2019

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a contact thermometer, and more particularly to a contact thermometer that directly contacts an object to detect the temperature of the object.

Contact-type thermometers have been proposed that include a protective portion (also referred to as a guard member) that directly contacts an object to be detected and protects the detection portion and the object to be detected (for example, Patent Documents 1 and 2). reference).

JP-A-4-309825 JP 2014-178221 A

By the way, when the protection part arranged around the detection part comes into direct contact with the detection object, the heat of the detection object is transferred through the protection part, and the temperature of the part where the detection part comes into contact decreases. There is a problem that the measurement accuracy is lowered due to the occurrence of

In relation to this, it is conceivable to use a member having a thermal conductivity lower than that of metal for the protective portion to avoid deterioration in measurement accuracy. Examples of members having lower thermal conductivity than metals include resins such as polyimide resins and fluorine resins, and ceramics (non-metallic inorganic materials) such as glass and zirconia.

However, resin, which has a lower thermal conductivity than metal, may deteriorate or melt at high temperatures (e.g., 260°C or higher), making it unsuitable for protective parts. . On the other hand, ceramics do not change in quality or melt even in such a high temperature environment, but there is a risk of breakage due to thermal shock fracture due to abrupt temperature changes. In this way, if the protection section is made of a material having a lower thermal conductivity than metal in order to avoid the deterioration of the measurement accuracy, another problem arises in that the replacement frequency of the protection section increases.

SUMMARY OF THE INVENTION An object of the present invention is to provide a contact-type thermometer that reduces the replacement frequency of a protective part while avoiding deterioration in measurement accuracy.

The contact thermometer of the present invention, which achieves the above objects, has a main body such that a detecting portion for detecting the temperature of an object to be detected and a protective portion disposed around the detecting portion are in direct contact with the object to be detected. In the contact-type thermometer arranged at the tip of the, the protective part is a convex body having a contact surface that contacts the object to be detected and a joint surface that is joined to the main body, and has a thermal conductivity higher than that of metal. A low heat-resistant member and a covering member made of a metal covering the heat-resistant member are provided, and the covering member covers the entire surface of the protective portion and excludes the sides of the protective portion surrounding the joint surface. It is characterized in that gaps are formed on the sides .
Further, in the contact thermometer of the present invention, the detecting portion for detecting the temperature of the object to be detected and the protective portion arranged around the detecting portion are arranged at the tip of the main body so that they are in direct contact with the object to be detected. The protective part is a heat-resistant member having a lower thermal conductivity than metal, and has a convex body having a contact surface that contacts an object to be detected and a joint surface that is joined to the main body. A covering member made of a metal covering the heat-resistant member is provided, and the covering member comprises at least a first covering plate that constitutes the contact surface, and a second covering plate that is separate from the first covering plate. It is characterized by

According to the present invention, by forming the protection part from a heat-resistant member with low thermal conductivity, when the protection part comes into direct contact with the object to be detected, the temperature of the part that the detection part comes into contact with is suppressed and measured. A decrease in accuracy can be avoided. Furthermore, according to the present invention, by covering the heat-resistant member with a covering member made of metal as a countermeasure against thermal shock occurring in the heat-resistant member, it is possible to reduce the replacement frequency of the protective portion.

1 is a perspective view illustrating an embodiment of a contact thermometer; FIG. FIG. 2 is a perspective view illustrating the heat-resistant member of FIG. 1; 2 is a perspective view illustrating a first covering plate of the covering member of FIG. 1; FIG. 2 is a perspective view illustrating a second covering plate of the covering member of FIG. 1; FIG.

An embodiment of a contact thermometer will be described below with reference to the drawings. In the drawings, the X direction and the Y direction are directions perpendicular to each other on the horizontal plane, and the Z direction is the vertical direction. In addition, as for the drawings, the dimensions are changed so that the configuration is easy to understand, and the ratio of thickness, width, length, etc. of each member and each part does not necessarily match the ratio of what is actually manufactured.

Hereinafter, the high temperature in the present disclosure is exemplified by the temperature at which resins such as engineering plastics and super engineering plastics stipulated in the product safety standards established by the American Underwriters Laboratories are degraded or deformed. More specifically, high temperature means a temperature of 260° C. to 300° C. or higher.

As illustrated in FIG. 1, a contact thermometer 10 according to the embodiment is a device that measures the temperature of an object to be detected (not shown). The contact-type thermometer 10 includes a head 11 disposed at the tip, a grip portion 12 disposed at the distal end of the head portion 11, and a signal line 13 led from the distal end of the grip portion 12 and connected to a temperature measuring device (not shown). The head 11 consists of a body 14 , a detection section 15 arranged at the tip of the body 14 , and a protection section 16 arranged around the detection section 15 .

The main body 14 is made of various materials such as stainless steel, fluororesin, glass cloth laminated plate, fernol resin, or polyimide resin, depending on the application. Using a material with low thermal conductivity, such as fernol resin or polyimide resin, is advantageous in suppressing heat transfer to the grip portion 12 through the main body 14 . It should be noted that the main body 14 does not come into direct contact with the object to be detected due to the detection portion 15 and the protection portion 16 .

The detection unit 15 is arranged in the center of the main body 14 when viewed in the Z direction, and directly contacts the detected object to detect the temperature of the contacted detected object. The detection unit 15 includes a contact plate 17 , a connecting member 18 and a temperature detection element 19 .

The contact plate 17 is formed of a thermal conductor such as a metal, extends in the Y direction, is pressed against the object to be detected and conducts heat from the object. and an opposite abutment surface. Connecting members 18 joined to both ends of the contact plate 17 in the Y direction protrude toward the protective portion 16 . is concatenated against The contact plate 17 is formed so as to be convexly curved toward the tip side in the Z direction in order to increase the adhesion with the object to be detected when it is pressed toward the object to be detected. In this embodiment, the contact plate 17 is configured to enhance the adhesion with the object to be detected by its own elastic force. Moreover, an urging member may be provided for elastically urging the contact plate 17 toward the tip side. The connection structure between the contact plate 17 and the protective portion 16 is not limited to the structure described above.

The temperature detecting element 19 has a temperature sensing part (also called temperature measuring junction) joined to the contact surface of the contact plate 17 . As the temperature detection element 19, type K using chromel for the positive electrode and alumel for the negative electrode, type E using chromel for the positive electrode and constantan for the negative electrode, and a platinum rhodium alloy (30% rhodium content) for the positive electrode. , - thermocouples of various types such as type B with platinum-rhodium alloy (6% rhodium content) in the poles, or various types such as platinum, nickel, copper, alloys of nickel and iron, and tungsten There are various types of temperature measuring resistors.

The protective portions 16 are arranged at both ends of the main body 14 in the X direction when viewed in the Z direction, and are arranged on both sides of the contact plate 17 of the detection portion 15 in the X direction. The number and arrangement of the protective portions 16 are not limited to this, and four protective portions 16 may be arranged at the four corners of the main body 14 when viewed in the Z direction. Further, a configuration may be adopted in which one protecting portion 16 having an annular shape when viewed in the Z direction is arranged so as to surround the detecting portion 15 .

The protective portion 16 is a convex body having a contact surface 16a that directly contacts the object to be detected at the tip in the Z direction and a joint surface 16b that is joined to the main body 14 at the end. The protective portion 16 of this embodiment forms a rectangular parallelepiped. In the present disclosure, a convex body is a solid that is convex, and includes a semi-cylinder and a hemisphere with curved surfaces in addition to convex polyhedrons including rectangular parallelepipeds and frustums whose boundaries are all straight lines. The contact surface 16a is arranged on the distal side of the contact surface of the contact plate 17, and directly contacts the detected object in a state in which the contact surface is pressed against the detected object and retracted toward the distal end. The shape of the protective portion 16 is not particularly limited as long as it is a convex body having a contact surface 16a and a joint surface 16b. Further, the contact surface 16a is desirably a surface parallel to the XY plane, but it is also possible to configure it with a cylindrical surface.

The protective portion 16 includes a heat-resistant member 20 and a covering member 30 , and the covering member 30 covers the heat-resistant member 20 . In the present disclosure, the configuration in which the covering member 30 covers the heat-resistant member 20 is not limited to the configuration in which the covering member 30 covers the entire outer surface of the heat-resistant member 20, and the outer surface of the heat-resistant member 20 is exposed to the outside. It shall include configurations that cover only the face. Moreover, the state in which the surface is covered is not limited to the state in which the entire surface is covered, but includes the state in which most of the area of the surface is covered and the remaining partial area is not covered.

As illustrated in FIG. 2, the heat-resistant member 20 is made of ceramics having a lower thermal conductivity than metal. The heat-resistant member 20 is preferably made of ceramics having a thermal conductivity lower than that of stainless steel, more preferably ceramics having a thermal conductivity lower than 15 W/m·k. The heat-resistant member 20 of this embodiment is a rectangular parallelepiped, and is composed of a front end surface 20a on the front end side in the Z direction, a terminal end surface 20b on the end side, two side surfaces 20c in the X direction, and two side surfaces 20d in the Y direction. The heat-resistant member 20 has a connecting hole 21 , a fastening hole 22 and a storage portion 23 . As the ceramics, those having high heat insulating properties in the high-temperature environment of the present disclosure are preferable, and glass and fine ceramics are exemplified. Examples of the heat-resistant member 20 include a rectangular parallelepiped formed by laminating a plurality of glass fiber fabrics or non-woven fabrics in the Z direction, and a rectangular parallelepiped formed of fine ceramics such as zirconia and cordierite.

The connecting hole 21 is formed in a side surface 20c of the heat-resistant member 20 facing the detecting portion 15, and is a hole into which the connecting member 18 is inserted. In this way, the connection hole 21 directly contacting the contact plate 17 and the connection member 18 is formed only in the heat-resistant member 20, and the connection member 18 has a non-contact structure with members other than the heat-resistant member 20. is desirable. This structure is advantageous in avoiding deterioration in measurement accuracy caused by heat transfer from the contact plate 17 via the connecting member 18 .

The fastening hole 22 is a through hole penetrating the heat-resistant member 20 in the Z direction, and a nut is embedded therein. After the heat-resistant member 20 is covered with the covering member 30, the fastening hole 22 and the through-hole formed in the main body 14 are communicated with each other, and a bolt is screwed from the distal end of the main body 14 to be screwed into the embedded nut. and is fastened to the main body 14 . It should be noted that a screw thread may be formed on the inner peripheral surface of the fastening hole 22 and a screw may be screwed from the distal end side of the main body 14 .

The housing portion 23 is arranged in the center of the end face 20b as viewed in the Z direction, and is formed by recessing the end face 20b from the end side toward the tip side, and the magnet 24 is housed therein. By storing the magnet 24 in the storage portion 23, it is possible to bring the contact plate 17 into close contact with the magnetic force when the object to be detected is a magnetic body. If the object to be detected is not a magnetic material, the magnet 24 may not be accommodated, and the accommodation portion 23 may not be formed.

The heat-resistant member 20 preferably has chamfered corners. In addition, it is preferable that the contact area between the tip surface 20a and the covering member 30 of the heat-resistant member 20 is small. Also, the contact area may be narrowed by forming a recess in the tip surface 20a.

As illustrated in FIGS. 3 and 4 , the covering member 30 is a member made of metal and consists of a first covering plate 31 and a second covering plate 32 . As the metal forming the coating member 30, a metal having heat resistance in the high-temperature environment of the present disclosure is preferable, and stainless steel and a nickel-based alloy are exemplified. The plate thickness of the metal plate forming the covering member 30 is preferably 1 to 6 times the plate thickness of the contact plate 17 of the detection unit 15 . If the plate thickness of the metal plate forming the coating member 30 is less than 1 times the plate thickness of the contact plate 17 of the detection unit 15, it is likely to be damaged and does not function as the protection unit 16. The amount of heat increases and measurement accuracy decreases.

The first covering plate 31 is made of a single metal plate, and when the metal plate is bent, it has three surfaces, namely, a tip surface 20a of the heat-resistant member 20 and two side surfaces 20d adjacent to both sides of the tip surface 20a in the Y direction. It is a member that covers the The first covering plate 31 has a tip surface covering piece 33, a side surface covering piece 34, a first fixed piece 35a, and a second fixed piece 35b.

The tip surface covering piece 33 is a portion that covers the tip surface 20 a , and the surface opposite to the side facing the tip surface 20 a serves as the contact surface 16 a of the protection portion 16 . The side surface covering pieces 34 are adjacent to both ends of the tip surface covering piece 33 in the Y direction, and cover the side surfaces 20 d while being bent with respect to the tip surface covering piece 33 . Further, the side surface covering piece 34 has a gap 36 which is a through hole at the boundary between the tip surface covering piece 33 and the side surface covering piece 34 .

The first fixing piece 35a is adjacent to the outer end of the side covering piece 34 in the Y direction, and is a portion that is hooked to the end surface 20b in a state where the side covering piece 34 is bent. A gap 36, which is a through hole, is formed at the boundary between the first fixing piece 35a and the side covering piece 34. As shown in FIG. The second fixing pieces 35b are adjacent to both ends of the tip surface covering piece 33 in the X direction, and are portions that are hooked on the side surface 20c in a state of being bent with respect to the tip surface covering piece 33 . Each of the first fixing piece 35a and the second fixing piece 35b does not need to cover the end surface 20b or the side surface 20c, and may be hooked to each surface. It is preferable that each of the first fixed piece 35a and the second fixed piece 35b has a small contact area with the second cover plate 32, which will be described later. It is advantageous to reduce the heat transfer amount of

The gap 36 is formed at each of the boundary between the tip surface covering piece 33 and the side surface covering piece 34 and the boundary between the side surface covering piece 34 and the first fixed piece 35a, which are the bent portions of the first covering plate 31 . The gap 36 functions as an escape hole for plastic deformation during bending of the first covering plate 31 and as an escape hole for strain due to thermal expansion during measurement. The gap 36 is an elongated through-hole that penetrates the metal plate forming the first covering plate 31 in the plate thickness direction (the Z direction in the drawing) and extends in the width direction (the Y direction in the drawing). exemplified. The shape of the gap 36 is not particularly limited as long as it functions as an escape hole both during bending and during measurement.

The second cover plate 32 is made of a single metal plate, and when the metal plate is bent, three faces are the end face 20b of the heat-resistant member 20 and the two side faces 20c adjacent to both sides of the end face 20b in the X direction. It is a member that covers the The second covering plate 32 has an end surface covering piece 37, side surface covering pieces 38a and 38b, and fastening through holes 39. As shown in FIG.

The terminal surface covering piece 37 is a portion that covers the terminal surface 20 b , and the surface opposite to the side facing the terminal surface 20 b serves as the joint surface 16 b of the protective portion 16 . The side surface covering piece 38a is adjacent to one end of the terminal surface covering piece 37 in the X direction, and covers the side surface 20c on the opposite side of the terminal surface covering piece 37 facing the detection unit 15 in a state of being bent. be.

The side surface covering piece 38 b is adjacent to the other end in the X direction of the terminal surface covering piece 37 and is a portion that covers the side surface 20 c that faces the detection unit 15 while being bent with respect to the terminal surface covering piece 37 . The side surface covering piece 38b has a shape that does not close the connecting hole 21 formed in the side surface 20c when viewed in the X direction. In the embodiment, the side covering piece 38a has a rectangular shape when viewed in the X direction, whereas the side covering piece 38b has a trapezoidal shape when viewed in the X direction. The shape of the side surface covering piece 38b is not limited to a trapezoid, but may be a rectangular shape similar to the shape of the side surface covering piece 38a. It's okay.

The fastening through-hole 39 is a through-hole that penetrates the terminal surface covering piece 37 and is formed so that the shaft of the bolt or screw that fastens the heat-resistant member 20 to the main body 14 can be inserted.

As illustrated in FIG. 1, the first covering plate 31 covers three surfaces, the tip surface 20a and both side surfaces 20d, of the heat-resistant member 20 in a state in which each piece is bent, and the first fixing piece 35a extends toward the end surface 20b. , and the second fixing piece 35b is caught on both side surfaces 20c. Thereby, the first cover plate 31 is fixed to the heat-resistant member 20 .

The second covering plate 32 covers three surfaces, the end surface 20b and both side surfaces 20c, of the heat-resistant member 20 to which the first covering plate 31 is fixed in a state where each piece is bent, and is fastened together with the heat-resistant member 20. fixed. The second cover plate 32 covers the first fixed piece 35a and the second fixed piece 35b together with the heat-resistant member 20, thereby preventing the fixed pieces from being unhooked.

In the state where the heat-resistant member 20 is covered with the covering member 30, each of the tip surface covering piece 33 and the side surface covering piece 34 of the first covering plate 31 and the side surface covering pieces 38a and 38b of the second covering plate 32 are separated from each other. A gap 40 is formed. This gap 40 is a gap formed by interposing the second fixed piece 35b of the first covering plate 31 between the side surface 20c of the heat-resistant member 20 and the side covering pieces 38a, 38b of the second covering plate 32. As shown in FIG. That is, the covering member 30 covers the entire surface of the protective portion 16, and gaps 36 and 40 are formed in the sides (also called corners) of the protective portion 16 excluding the sides surrounding the joint surface 16b.

As described above, in the contact thermometer 10 of the present embodiment, the protective portion 16 that protects the object to be detected and the detection portion 15 is composed of the heat-resistant member 20 having a lower thermal conductivity than metal and the metal that covers the heat-resistant member 20. A covering member 30 is provided. Therefore, the direct contact of the covering member 30 with the object to be detected at a high temperature can alleviate the sudden temperature distribution inside the heat-resistant member 20 and suppress the heat-resistant member 20 from being damaged by thermal shock.

Moreover, even if the heat-resistant member 20 is damaged by cracks due to thermal shock, or by collapsing, peeling, or the like, the covering member 30 covering the heat-resistant member 20 can prevent scattering of broken pieces of the heat-resistant member 20 and deformation of the outer shape. can.

In other words, by configuring the protection part 16 with the heat-resistant member 20 having a low thermal conductivity, when the protection part 16 comes into direct contact with the object to be detected, the temperature of the part where the detection part 15 contacts is suppressed and measurement is performed. A decrease in accuracy can be avoided. In addition to this, as described above, by covering the heat-resistant member 20 with the covering member 30 as a countermeasure against thermal shock occurring in the heat-resistant member 20, the replacement frequency of the protective portion 16 can be reduced.

It is desirable that the measurement accuracy covering member 30 covers the entire surface of the protective portion 16 and that gaps 36 and 40 are formed in the sides of the protective portion 16 excluding the side surrounding the joint surface 16b. According to this configuration, the coating member 30 is made thin to reduce the amount of heat transferred from the object to be detected, thereby avoiding deterioration in measurement accuracy. Distortion caused by the strain is relieved, and deformation of the outer shape of the protection portion 16 can be suppressed. Although the measurement accuracy is lower than that of the embodiment, the thickness of the covering member 30 may be set to a thickness capable of suppressing deformation due to thermal expansion, and the covering member 30 may be configured in a box shape with no gaps on all sides.

In addition, the covering member 30 includes a first covering plate 31 covering three surfaces, that is, the tip surface 20a of the heat-resistant member 20 and two side surfaces 20d adjacent to both sides of the tip surface 20a in the Y direction, the terminal surface 20b of the heat-resistant member 20 and the It is desirable to be composed of two side surfaces 20c adjacent to both sides in the X direction of the end surface 20b and a second covering plate 32 covering three surfaces. In this way, by configuring the covering member 30 with at least the first covering plate 31 that constitutes the contact surface 16a and the second covering plate 32 that is separate from the first covering plate 31, the amount of heat transfer from the object to be detected is is advantageous for reducing The covering member 30 may be composed of a single metal plate, although the measurement accuracy is lower than that of the embodiment.

10 contact-type thermometer 14 body 15 detector 16 protector 20 heat-resistant member 30 covering member

Claims (3)

A contact-type thermometer arranged at the tip of a main body so that a detecting portion for detecting the temperature of an object to be detected and a protective portion arranged around the detecting portion are in direct contact with the object to be detected,
The protection part is a convex body having a contact surface that contacts the object to be detected and a joint surface that is joined to the main body, and is made of a heat-resistant member having a lower thermal conductivity than metal and a metal that covers the heat-resistant member. and a covering member, the covering member covering the entire surface of the protective portion, and a gap being formed in a side of the protective portion excluding a side surrounding the joint surface among the sides of the protective portion. Contact thermometer. 2. A contact thermometer according to claim 1 , wherein said covering member comprises at least a first covering plate forming said contact surface and a second covering plate separate from said first covering plate. A contact-type thermometer arranged at the tip of a main body so that a detecting portion for detecting the temperature of an object to be detected and a protective portion arranged around the detecting portion are in direct contact with the object to be detected,
The protection part is a convex body having a contact surface that contacts the object to be detected and a joint surface that is joined to the main body, and is made of a heat-resistant member having a lower thermal conductivity than metal and a metal that covers the heat-resistant member. a covering member, wherein the covering member comprises at least a first covering plate forming the contact surface, and a second covering plate separate from the first covering plate. Total.

Images