JP7216989B2 - Temperature calibrator and manufacturing method thereof - Google Patents

Description

The present invention relates to a temperature calibrator and its manufacturing method, and more particularly to a temperature calibrator with improved repeatability and its manufacturing method.

A temperature calibrator including a reference thermometer, a heating device, and a calibration block has been proposed as a device for calibrating a contact-type thermometer that is brought into contact with a temperature-measuring object to measure its temperature (see, for example, Patent Document 1). This temperature calibrator has a calibration block made of copper or a copper alloy.

U.S. Pat. No. 6,527,437

By the way, copper and copper alloys have the property of being gradually oxidized in the air to form an oxide film on the surface. Such an oxide film is likely to form when the temperature is relatively high.

Therefore, in the temperature calibrator described in Patent Document 1 whose calibration block is made of copper or copper alloy, when the temperature calibrator reaches a relatively high temperature (for example, 450 ° C.) during calibration of the contact thermometer, calibration As the block thermally expands, an oxide film forms on its surface. When the temperature of the calibration block returns to room temperature, the oxide film formed during thermal expansion shrinks and becomes easier to separate from the surface of the calibration block. In addition, when the oxide film peels off and the surface of the calibration block becomes uneven, the contact state with the thermometer changes, which is a factor in lowering the repeatability of calibration.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a temperature calibrator and a manufacturing method thereof that prevent oxidation of the surface of the calibration block and improve repeatability.

A temperature calibrator for achieving the above object comprises a reference thermometer, a heating device, and a calibration block. A calibration surface is formed on the temperature calibrator heated by the heating device, wherein the calibration block includes a main body portion and a covering portion, and includes the main body including the inner surface of the insertion hole formed in the main body portion. The entire surface of the part is covered so as to be sealed with the coating part, the material of the coating part has higher corrosion resistance than the material of the main body part, and the coefficient of linear expansion is the same as that of the material of the main body part. It is characterized by a value of 90% to 110% of the expansion coefficient.

A temperature calibrator manufacturing method for achieving the above object comprises a reference thermometer, a heating device, and a calibration block, wherein the calibration block includes an insertion hole into which the reference thermometer is inserted, In the manufacturing method of the temperature calibrator, which is heated by the heating device, the calibration block is formed by covering the entire surface of the main body of the pillar with the covering so as to be sealed. In the step of brazing the main body and the covering while the thickness of the covering is set to a thickness that can suppress deformation due to heat compression in brazing, the entire surface of the main body is a step of covering with the covering portion, and cutting in the direction of the column axis the covering portion on the side where the calibration surface is to be formed, of the portions covering both end surfaces of the main body portion in the direction of the column axis; reducing the thickness from the thickness that can suppress the deformation to the thickness that functions as the calibration surface.

According to the present invention, the entire surface of the main body of the calibration block, including the inner surface of the insertion hole and the calibration surface, has higher corrosion resistance than the main body, is less susceptible to oxidation, and has a degree of deformation during thermal expansion that is about the same as that of the main body. Oxidation of the entire surface of the main body can be prevented by forming a seal with the cover. This is advantageous for maintaining contact between the thermometer to be calibrated and the calibration surface, and repeatability can be improved without exchanging the calibration block.

1 is a perspective view illustrating an embodiment of a temperature calibrator of the present invention; FIG. FIG. 2 is a perspective view of the temperature calibrator of FIG. 1 viewed from section A; FIG. 2 is an explanatory diagram of an example of a method of manufacturing the temperature calibrator of FIG. 1; FIG. 10 illustrates another embodiment of the temperature calibrator of the present invention; FIG. 5 illustrates yet another embodiment of the temperature calibrator of the present invention;

The temperature calibrator of the present invention will be described below.

As illustrated in FIGS. 1 and 2, the temperature calibrator 1 of the embodiment of the invention comprises a reference thermometer 2, a heating device 3 and a calibration block 4. FIG. Note that the reference thermometer 2 and the heating device 3 are shown outside the calibration block 4 in FIG. 1 to avoid complication. In this embodiment, the direction parallel to the end face of the calibration block 4 in the column axis direction is the X direction, the direction parallel to the end face and perpendicular to the X direction is the Y direction, the X direction and the Y direction. The column axis direction (vertical direction), which is a vertical direction, is defined as the Z direction.

The reference thermometer 2 is a device that satisfies the requirements of the 1990 International Temperature Scale (also called ITS-90) and is calibrated according to the method defined by the International Temperature Scale. As the reference thermometer 2, a resistance temperature detector is exemplified. The reference thermometer 2 is a straight-tube device inserted into the calibration block 4 .

The heating device 3 is a device for heating the calibration block 4 . The heating device 3 is a straight-tube-shaped device and is inserted into the calibration block 4 at a position below the insertion position of the reference thermometer 2 in the Z direction. The heating device 3 includes, for example, a nichrome wire (heating element) wound around a rod-shaped core member made of ceramics or the like in a coil shape, and the whole core member and the heating element are housed in a stainless steel protective tube. consists of

The heating device 3 may be spirally wound around the calibration block 4 around the outer peripheral surface of the main body 6 at a position below the insertion position of the reference thermometer 2 in the Z direction. A configuration in which the heating device 3 is arranged inside the heating device 4 is preferable because the necessary materials are small and the cost is low.

The calibration block 4 has a body portion 6 and a covering portion 7, and the entire surface of the body portion 6 is covered with the covering portion 7 so as to be sealed. The calibration block 4 is a cylindrical device as a whole, and has a calibration surface 5 on its upper end face (one end face) in the direction of the column axis. In the calibration block 4, insertion holes 8 and 9 penetrating the side surfaces of the column are formed in order from the upper side in the Z direction. In the present disclosure, the entire surface of body portion 6 includes the inner surfaces of insertion holes 8 and 9 formed in body portion 6 .

The main body 6 is a cylindrical member made of a thermally conductive material capable of transferring heat from the heating device 3 to the reference thermometer 2 and the calibration surface 5 . Copper or a copper alloy is exemplified as the material of the body portion 6 . The shape of the calibration block 4 and the main body 6 is not limited to a cylindrical body, and may be other columnar bodies such as prismatic bodies.

The covering portion 7 is a member formed of a material having higher corrosion resistance than the material of the body portion 6 and having a coefficient of linear expansion of 90% to 110% of the coefficient of linear expansion of the material of the body portion 6. . As a material of the covering portion 7, stainless steel is exemplified when the body portion 6 is made of copper or a copper alloy. If the coefficient of linear expansion of the material of the covering portion 7 is less than 90% of the coefficient of linear expansion of the material of the main body portion 6, the amount of thermal expansion of the main body portion 6 becomes excessive compared to the covering portion 7, and the heat of the main body portion 6 increases. There is a concern that a portion of the covering portion 7 may be damaged due to the expansion. When the coefficient of linear expansion of the material of the covering portion 7 exceeds 110% of the coefficient of linear expansion of the material of the main body portion 6, the amount of thermal expansion of the covering portion 7 becomes excessive compared to the main body portion 6, and the covering portion 7 and the main body portion There is a concern that the bonding strength of 6 will decrease. Therefore, the linear expansion coefficient of the material of the covering portion 7 is 90% to 110% of the linear expansion coefficient of the material of the main body portion 6 . The coefficient of linear expansion indicates the rate at which the length of an object expands per temperature when the temperature of the object rises within a preset temperature range (eg, 0° C. to 800° C.). Corrosion resistance is an index representing the resistance to oxidation of an object due to redox reactions with components in the surrounding environment. If the corrosion resistance is high, the object is difficult to oxidize.

The calibration surface 5 is a portion with which the temperature sensing part of the contact thermometer to be calibrated comes into contact. The thickness Ht between the upper surface of the main body part 6 and the calibration surface 5 is such that there is no irreversible deformation due to contact with the contact thermometer, and the positional relationship between the heating device 3, the reference thermometer 2, and the calibration surface 5 is A thickness that functions as a calibration surface 5 based on heat conduction is desirable. In the present disclosure, the thickness Ht between the upper surface of the body portion 6 and the calibration surface 5 is the sum of the thickness of the covering portion 7 and the thickness of the brazing filler metal 10 .

The insertion hole 8 is a hole into which the reference thermometer 2 is inserted in the X direction, and the insertion hole 9 is a hole into which the heating device 3 is inserted in the X direction. Both of the insertion holes 8 and 9 are cylindrical holes penetrating the body portion 6 and the cover portion 7, and are formed by, for example, boring. The reference thermometer 2 is inserted into the insertion hole 8 so that the temperature sensing part 2t at the tip of the reference thermometer 2 is located at a position halfway along the extension length (approximately at the center of the calibration block 4 in the X direction). inserted. A heating device 3 is inserted into the insertion hole 9 over the entire extension length thereof.

The insertion holes 8 and 9 may be bottomed cylindrical holes that are formed halfway through the inside of the calibration block 4, but they are formed as holes penetrating the column in the lateral direction of the calibration block 4. It is desirable that When formed as a through hole, the reference thermometer 2 and the heating device 3 can be taken out by pushing and pulling from either one of the two holes formed in the side surface of the calibration block 4. It is effective when the product is damaged or replaced. In particular, since the heating device 3 is inserted into the insertion hole 9 with almost no gap in order to suppress an increase in thermal resistance due to air between it and the calibration block 4, it is difficult to insert and remove it. The effectiveness of forming as

The covering portion 7 is joined to the main body portion 6 by brazing through hard solder 10 . Silver solder is exemplified as the hard solder 10 . If the brazing filler metal 10 covers the entire surface of the main body 6 , the main body 6 is sealed with both the covering part 7 and the brazing filler metal 10 , which is advantageous for securing the sealing performance of the main body 6 .

The covering portion 7 is configured by combining separate members 11 to 15 covering respective surfaces of the main body portion 6 . The calibration surface plate 11 is a cylindrical body that covers the upper end surface of the main body 6 in the direction of the column axis and constitutes the calibration surface 5 . The end face plate 12 is a cylindrical body that covers the lower end face of the main body 6 in the column axis direction and constitutes the end face of the calibration block 4 on the side opposite to the calibration surface 5 in the column axis direction. The end surface area of the calibration surface plate 11 is substantially the same as the end surface area of the end surface plate 12 . The cylindrical body 13 for cylindrical surface is a hollow cylindrical body that covers the side surface of the main body 6 and constitutes the side surface of the calibration block 4 . The insertion hole cylindrical bodies 14 and 15 are cylindrical members that are inserted into the insertion holes 8 and 9 respectively and constitute the entire inner surface of the calibration block 4 . The insertion hole cylindrical bodies 14 and 15 are joined to the entire inner surfaces of the insertion holes 8 and 9 with brazing filler metal 10, respectively. The reference thermometer 2 is inserted into the hollow portion 14a of the cylindrical body 14 for insertion hole. The heating device 3 is inserted into the hollow portion 15 a of the insertion hole cylindrical body 15 . When the insertion holes 8 and 9 are bottomed cylindrical holes formed halfway through the inside of the calibration block 4, the insertion hole cylindrical bodies 14 and 15 are bottomed cylindrical holes. It is formed as a member.

The thickness Ht is suitable for calibrating a contact thermometer. The calibration surface 5 is a surface with which the contact thermometer contacts and is exposed to the air. In other words, the thickness Ht should be within a range in which the thermal resistance between the upper surface of the main body 6 and the calibration surface 5 can be ignored, considering the presence of air with high thermal resistance.

The thickness (length in the column axis direction) h of the calibration surface plate 11 is the same as the thickness Ht between the upper surface of the main body 6 and the calibration surface 5 minus the thickness of the brazing filler metal 10. . The thickness h of the calibration surface plate 11 is smaller than the thickness H of the end plate 12 . The calibration surface plate 11 and the insertion hole cylindrical bodies 14 and 15 are formed thinner than the end surface plate 12 and the column surface cylindrical body 13 .

One ends of the reference thermometer 2 and the heating device 3 are connected to a temperature controller 18 via wires 16 and 17, respectively. The temperature controller 18 is a device that measures the voltage applied to the reference thermometer 2 and acquires the temperature of the reference thermometer 2 corresponding to the measured voltage. The temperature controller 18 also energizes the heating device 3 to cause the heating device 3 to generate heat. The amount of heat generated by the heating device 3 is in direct proportion to the amount of power supplied from the temperature controller 18 to the heating device 3 .

A calibration principle of a contact thermometer to be calibrated using the temperature calibrator 1 will be described. This calibration is performed by heating the heating device 3 with the temperature sensing part of the contact thermometer to be calibrated in contact with the calibration surface 5, and based on the temperature of the reference thermometer 2 obtained by the temperature controller 18. This is done so that the estimated temperature of the calibration surface 5 and the temperature displayed on the contact thermometer to be calibrated match. T1 is the obtained temperature value of the reference thermometer 2, T2 is the set temperature of the heating device 3, a is the separation distance in the Z direction between the heating device 3 and the reference thermometer 2, and the separation in the Z direction between the heating device 3 and the calibration surface 5 Assuming that the distance is b, the estimated value T of the temperature of the calibration surface 5 is calculated by the following formula (1).

The amount of heat generated by the heating device 3 is transmitted to the reference thermometer 2 and the calibration surface 5 via the calibration block 4 . Since the calibration surface 5, the reference thermometer 2, and the heating device 3 are arranged in this order from the upper side in the Z direction, the amount of heat transmitted to the calibration surface 5 is smaller than that of the reference thermometer 2, and each device 2 , 3 and 5, the temperature decreases in the order of the heating device 3, the reference thermometer 2, and the calibration surface 5. The amount of heat transferred from the heating device 3 to the heat transfer objects 2 and 5 is in direct proportion to the distance between the heating device 3 and the heat transfer objects 2 and 5 . In other words, the temperature difference between the heating device 3 and the heat transfer objects 2 and 5 is in direct proportion to the distance between the heating device 3 and the heat transfer objects 2 and 5 . A temperature difference ΔT (=T2−T1) between the set temperature T2 of the heating device 3 and the obtained temperature value T1 of the reference thermometer 2 is a value corresponding to the separation distance a between the heating device 3 and the reference thermometer 2. Considering the relationship of direct proportion between the temperature difference and the distance, the temperature difference ΔT′ between the temperature T of the calibration surface 5 and the set temperature T2 of the heating device 3 is the distance b between the calibration surface 5 and the heating device 3 and the above is calculated by multiplying the ratio (=b/a) of the separation distance a by the temperature difference .DELTA.T, and is the second term on the right side of the formula (1). The temperature T of the calibration surface 5 is estimated and calculated by subtracting the temperature difference ΔT' from the set temperature T2 of the heating device 3, as in Equation (1).

The estimation calculation of the temperature T of the calibration surface 5 using the above formula (1) is performed by arranging the calibration surface 5, the reference thermometer 2, and the heating device 3 in order from the upper side in the Z direction in the calibration block 4, and This holds on the premise that the thickness between the upper surface and the calibration surface 5 is a thickness that allows heat transfer from the heating device 3 to the calibration surface 5 to the extent that equation (1) holds.

With such a configuration, it is possible to estimate and calculate the temperature T of the calibration surface 5 using a simple calculation formula such as Equation (1).

The contact-type thermometer to be calibrated is a thermometer that measures the temperature of the object to be measured by bringing its temperature sensing part into contact with the object to be measured, and the temperature sensing part is composed of a contact plate. A thermometer. This contact-type thermometer is different from a non-contact thermometer and an insertion-type thermometer that measure the temperature of a temperature-measuring object based on radiation from the temperature-measuring object.

As described above, the temperature calibrator 1 has a structure in which the entire surface of the calibration block 4 including the inner surfaces of the insertion holes 8 and 9 and the calibration surface 5 is covered with the covering portion 7 . Since the covering portion 7 has higher corrosion resistance than the main body portion 6 and is less likely to be oxidized, and the degree of deformation during thermal expansion is about the same as that of the main body portion 6, the sealed state can be maintained. Therefore, the temperature calibrator 1 can prevent the entire surface of the main body 6 from being oxidized. This is advantageous for maintaining the contact state between the thermometer to be calibrated and the calibration surface 5, and the repeatability can be improved without exchanging the calibration block 4. FIG. In addition, by preventing the oxidation of the entire surface of the body portion 6 by the covering portion 7, the volume of the body portion 6 gradually decreases due to peeling of the oxide film formed on the surface of the body portion 6, and the heat capacity decreases. You can prevent change. Therefore, the replacement frequency of the calibration block 4 is reduced, and the cost required for replacement of the calibration block 4 can be reduced.

In the temperature calibrator 1, the cover portion 7 is configured by combining separate members 11 to 15 covering the surfaces of the main body portion 6. As shown in FIG. Since the body portion 6 including the insertion holes 8 and 9 is sealed by the insertion hole cylindrical bodies 14 and 15, it is advantageous to seal the entire surface including the inner surface of the body portion 6 with the covering portion 7. .

The calibration surface plate 11 and the end surface plate 12 can be made of general-purpose stainless steel plates, and the column surface cylindrical body 13 and the insertion hole tubular bodies 14 and 15 can be made of general-purpose stainless steel pipes. , the material cost can be reduced.

A method of manufacturing the temperature calibrator 1 will be described with reference to FIG. This manufacturing method is composed of the following 1st to 6th steps, and may include at least the 4th and 6th steps. In the first step, the body portion 6 and the covering portion 7 are manufactured separately. The covering portion 7 is manufactured separately for each of the members 11-15. At this stage of the process, the calibration surface plate 11 is manufactured so that its thickness is greater than the thickness h of the completed calibration surface plate 11 shown in FIG. This thickness is a thickness that does not distort and deform the shape of the calibration surface plate 11 even when the calibration surface plate 11 is heated and pressurized (heated and compressed) in a later process. is set to a thickness that can suppress Since the calibration surface plate 11 and the end surface plate 12 are both cylindrical bodies, the thickness and bottom area of the calibration surface plate 11 at this stage of the process are the same as the thickness and bottom area of the end surface plate 12. The bottom area is preferable because the time required for manufacturing these members 11 and 12 can be shortened.

It is preferable to set the thickness of the end plate 12 to be the same as the thickness H of the completed end plate 12 shown in FIG.

Further, if the calibration block 4 and the body portion 6 are cylindrical, for example, the calibration block 4 can be manufactured by combining a copper round bar and a stainless steel pipe (cylinder) or plate. Therefore, it is preferable because the cost required for manufacturing can be suppressed.

At the stage of this process, insertion holes 8 and 9 for inserting the two insertion hole cylindrical bodies 14 and 15 are formed in the main body 6 and the column surface cylindrical body 13 .

In the second step, members 11 to 15 are arranged around the body portion 6, as shown in FIG. At this time, the calibration surface plate 11 is arranged below one end surface of the main body 6 in the columnar axis direction, and the end surface plate 12 is arranged above the other end surface of the main body 6 in the columnar axis direction in the Z direction. spaced apart. Since the compressive force F is applied to the covering portion 7 from the upper side in the Z direction in a later process, the object to which the compressive force F is directly applied is not the calibration surface plate 11 but the end surface plate 12, so that the compressive force F This is to reliably prevent deformation of the calibration surface plate 11 due to The column surface cylindrical body 13 is arranged so as to surround the entire column surface of the body portion 6 . After arranging the calibration surface plate 11, the end surface plate 12, and the column surface cylindrical body 13 around the main body 6, the two insertion hole cylindrical bodies 14 and 15 are inserted into the insertion holes 8 and 9, respectively. placed.

In the third step, a solid brazing filler metal 10 is applied to the upper end face in the Z direction of the calibration surface plate 11 and the other end face of the main body 6 .

In the fourth step, a compressive force F is applied to the end plate 12 from above in the Z direction while heating the main body portion 6, the covering portion 7 and the brazing filler metal 10 as a whole using a separate heater or the like. This heating is performed to such an extent that the solid state brazing filler metal 10 can be raised to and maintained at a temperature (for example, 450° C.) at which it changes to a liquid state. During this heating, the brazing filler metal 10 in a liquid state spreads due to the compressive force F and enters the gap between the main body portion 6 and the covering portion 7 . This heating and pressurization is performed for a sufficient time (for example, 5 minutes) so that the entire surface of the main body 6 is covered with the coating 7 via the brazing filler metal 10 . Since the thickness of the covering portion 7 is such that the covering portion 7 is not deformed even when the covering portion 7 is heated and compressed, the covering portion 7 is not deformed by the heating and compression.

In the fifth step, the main body portion 6, the covering portion 7 and the brazing filler metal 10 are all cooled down to about room temperature (25° C.). This cooling is performed using a separate cooling device (for example, a fan). Due to this cooling, the brazing filler metal 10 that has entered the gap between the main body 6 and the covering part 7 is solidified, and the covering part 7 is joined to the entire surface of the main body part 6 via the brazing filler metal 10 .

In other words, in the fourth and fifth steps, the hard solder 10 is used to braze the covering portion 7 onto the entire surface of the body portion 6 . More specifically, brazing involves melting the hard solder 10 having a lower melting point than the melting points between the main body portion 6 and the covering portion 7 to be joined, and allowing the melted hard solder 10 to permeate and diffuse by capillary action. The main part 6 and the covering part 7 are joined together by cooling and solidifying the braze 10 . This brazing is an advantageous joining method for forming the calibration block 4 as a cylindrical body without irregularities because the body portion 6 and the covering portion 7 are less likely to be thermally deformed during joining compared to other joining methods. be.

In the sixth step, the thickness of the calibration surface plate 11, which is the covering portion 7 on which the calibration surface 5 is formed, is changed from the thickness H in the first step to the thickness h of the calibration surface plate 11 shown in FIG. The calibration surface plate 11 is thinned by cutting it by a thickness h1 (=Hh) in parallel with both end faces of the main body 6 in the direction of the column axis. This cutting is performed with the entire temperature calibrator 1 turned upside down and the end face plate 12 grounded on a workbench. The thickness h is a thickness that does not affect the heat transfer between the heating device 3 and the calibration surface 5 by the covering portion 7, more specifically, a thickness that satisfies the above formula (1). set. In addition, when the brazing filler metal 10 protrudes outside the outer surface of the calibration block 4, the protruding portion is cut off to form the calibration block 4 as a whole into a cylindrical body.

As described above, in the manufacturing method of the temperature calibrator of the present invention, at the stage of joining the body portion 6 and the covering portion 7, the thickness of the calibration surface plate 11 is set to a thickness that can withstand the heat and pressure required for joining. To improve durability of a front panel 11. - 特許庁After completion of this bonding, the thickness of the calibration surface plate 11 is reduced to the extent that the above equation (1) holds without affecting the heat transfer between the heating device 3 and the calibration surface 5. . As a result, deformation of the calibration surface plate 11 during manufacturing can be prevented, and the function of the calibration surface 5 can be maintained during calibration.

In this embodiment, the temperature calibrator 1 having one reference thermometer 2 is used as an example, but as illustrated in FIG. 4, a plurality of (three in FIG. The present invention can also be applied to the temperature calibrator 1 having In this case, the corresponding insertion hole cylinders are attached to the corresponding insertion holes 8a, 8b, 8c of the respective reference thermometers 21, 22, 23 connected to the temperature controller 18 via the wirings 16a, 16b, 16c. Shaped bodies 14a, 14b, and 14c are inserted. When n (n≧1) reference thermometers are inserted and arranged in the calibration block 4, the temperature of the reference thermometer 2k (k=1 to n) is T1 _k , the set temperature of the heating device 3 is T2, and the heating Assuming that the distance in the Z direction between the device 3 and the reference thermometer 2k is a _k , and the distance between the heating device 3 and the calibration surface 5 is b, the estimated value of the temperature of the calibration surface 5 is calculated by the following equation (2). be.

As in the case where only one reference thermometer 2 is provided in the calibration block 4, the temperature difference between the heating device 3 and the heat transfer objects 21, 22, 23, 5 is , 5 is directly proportional to the distance between . Using this relationship, the average temperature difference between the reference thermometer 2k and the heating device 3 is calculated. and the temperature difference between the heating device 3 (the second term on the right side of Equation 2). The temperature T of the calibration surface 5 is estimated and calculated by subtracting the above temperature difference from the set temperature T2 of the heating device 3 as shown in Equation (2).

In this case, since the temperature difference between the calibration plane 5 and the heating device 3 is calculated based on the average value of the temperature differences between the plurality of reference thermometers 2k and the heating device 3, the calibration plane 5 based on the temperature T2 of the heating device 3 The estimation accuracy of the temperature T of can be improved.

Further, as illustrated in FIG. 5, the entire upper end surface of the calibration surface plate 11 is covered with a coating film 19 made of ceramics, which is more durable than the coating portion 7, and the coating film 19 is It may be the calibration surface 5 of the calibration block 4 . The thickness of the coating film 19 is such that the total value Ht1 of this thickness, the thickness h of the calibration surface plate 11, and the brazing thickness functions as the calibration surface 5, in other words, the above equation (1) , (2) is established. Therefore, when the coating film 19 is formed, it is cut in the sixth step so that the calibration surface plate 11 is further thinned by the thickness of the coating film 19 . Furthermore, since the calibration surface plate 11 is joined to the main body 6 by brazing, it is preferable to reduce the thickness of the calibration surface plate 11 by cutting the thickness of the brazing material. In this case, the coating film 19 can prevent the calibration surface 5 from being damaged due to contact between the temperature sensing part of the thermometer to be calibrated and the calibration surface 5 while maintaining the function of the calibration surface 5 .

Reference Signs List 1 temperature calibrator 2 reference thermometer 3 heating device 4 calibration block 5 calibration surface 6 main body 7 cover 8 reference thermometer insertion hole 9 heating device insertion hole 10 brazing filler metal 11 calibration surface plate 12 end surface plate 13 Cylindrical body 14 for cylindrical surface 14a Cylindrical body for insertion hole for reference thermometer Hollow part 15 Cylindrical body 15a for insertion hole for heating device Hollow parts 16, 17 Wiring 18 Temperature controller 19 Coating film

Claims (7)

A reference thermometer, a heating device, and a calibration block, wherein the calibration block is formed with an insertion hole into which the reference thermometer is inserted and a calibration surface on which the thermometer to be calibrated measures temperature, and the heating device In a temperature calibrator heated by
The calibration block includes a main body and a cover, and the entire surface of the main body including the inner surface of the insertion hole formed in the main body is covered with the cover so as to be sealed,
Temperature calibration characterized in that the material of the covering part has higher corrosion resistance than the material of the main body part, and its linear expansion coefficient is a value of 90% to 110% of the linear expansion coefficient of the material of the main body part vessel. the insertion hole is disposed between the calibration surface and the heating device;
The thickness of the covering portion between the calibration surface and the body portion is the ratio of the distance between the heating device and the reference thermometer and the distance between the heating device and the calibration surface to the heating device and the ratio of the temperature difference between the reference thermometer and the temperature difference between the heating device and the calibration surface. The insertion hole is arranged between the calibration surface and the heating device, the covering portion is joined to the main body portion via hard solder, and a gap between the calibration surface and the main body portion is provided. The total thickness of the coating portion and the brazing filler metal is the ratio of the distance between the heating device and the reference thermometer and the distance between the heating device and the calibration surface, and the heating device and the ratio of the temperature difference between the reference thermometer and the temperature difference between the heating device and the calibration surface . the calibration block includes a coating film having a hardness higher than that of the coating portion;
The insertion hole is arranged between the calibration surface and the heating device, the covering portion is joined to the main body portion via hard solder, and the calibration surface covers the covering portion. The total thickness of the thickness of the coating film between the calibration surface and the main body portion, the thickness of the coating portion, and the thickness of the hard solder is determined by the heating device and the reference thermometer. and the ratio of the distance between the heating device and the calibration surface to the ratio of the temperature difference between the heating device and the reference thermometer and the temperature difference between the heating device and the calibration surface. The temperature calibrator of claim 1 , wherein the temperature is 5. The temperature calibrator according to claim 3 , wherein the brazing filler metal covers the entire surface of the main body. The calibration block forms a column, the calibration surface is formed on one end face in the direction of the column axis, and the insertion hole is formed through the side surface of the column,
The covering part is
a calibration surface plate that constitutes the calibration surface; an end surface plate that constitutes an end surface opposite to the one end surface; a column surface cylindrical body that constitutes a side surface of the column; The temperature calibrator according to any one of claims 1 to 5 , wherein the temperature calibrator comprises a cylindrical body for an insertion hole forming a surface. A reference thermometer, a heating device, and a calibration block, wherein the calibration block is formed with an insertion hole into which the reference thermometer is inserted and a calibration surface on which the thermometer to be calibrated measures temperature, and the heating device A method of manufacturing a temperature calibrator heated by
The step of creating the calibration block by sealingly covering the entire surface of the main body portion of the column with the covering portion;
The main body and the covering part are brazed in a state where the thickness of the covering part is set to a thickness that can suppress deformation due to heat compression in brazing, and the entire surface of the main body part is covered with the covering part. a covering process;
The deformation can be suppressed by cutting the thickness of the covering portion on the side forming the calibration surface of the covering portion covering both end surfaces of the body portion in the columnar axis direction in the columnar axis direction. and a step of reducing the thickness from a thickness to a thickness that functions as the calibration surface.

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