Resistance temperature detector-equipped heater, heater-equipped construction element including same, and heater installation method

Abstract

The purpose of the present invention is to provide a resistance temperature detector-equipped heater which comprises a low-heat conductor provided between a resistance temperature detector and a sheet-shaped heater and which, when the resistance temperature detector-equipped heater is installed on the outer surface of a construction element such as piping and then electrified so that the temperature of the resistance temperature detector is set to a desired temperature, makes it possible to also set the temperature of the outer surface of the construction element to a temperature close to the desired temperature. The purpose is achieved by a resistance temperature detector-equipped heater comprising a sheet-shaped heater and a resistance temperature detector, said resistance temperature detector-equipped heater further comprising a low-heat conductor provided between the sheet-shaped heater and the resistance temperature detector, wherein the low-heat conductor has thermal conductivity with which the difference (T1-T2) between a temperature (T1) indicated by the resistance temperature detector and the temperature (T2) of the outer surface of a construction element during use is within ±3°C.

Description

Resistance temperature detector heater, heater-equipped construction body including the same, and heater installation method

[0001] The present invention relates to a heater with a resistance temperature detector, a heater-equipped installation body including the heater, and a heater installation method.

[0002] Conventionally, heater devices have been proposed for heating pipes, etc. For example, Patent Document 1 describes a heater device for heating an object having a two-dimensional or three-dimensional curved surface, such as a pipe, a valve, or other object, comprising a heater mat of heat-generating material composed of a flexible, substantially non-stretchable solid substrate, having an inner surface shaped and sized to surround the object and conform to the curved surface of the object, and an outer surface radially spaced from the inner surface, and further comprising a jacket immovably attached to the outer surface of the heater mat, the jacket being an elastic, stretchable, and compressible composite material formed by distributing air or gas bubbles throughout the solid material, the composite material having a lower density, higher elasticity and compressibility, lower thermal conductivity, a greater thickness, and sufficient elastic resistance to compression compared to the heater mat, so that when an external force deforming the heater mat is removed, the inner surface of the heater mat has an intrinsic memory for returning to a size and shape that can surround and conform to the curved surface of the object and maintain the size and shape.

[0003] Special Publication No. 2000-505582

[0004] When a sheet heater is installed on the outer surface of a pipe or other object and electricity is applied to adjust the sheet heater to a desired temperature, the temperature of the outer surface of the object tends to be lower than the temperature of the sheet heater. The inventors believe that this is mainly due to the formation of a gap between the sheet heater and the outer surface of the object. Therefore, if you want to adjust the outer surface of the object to a desired temperature, you need to set the temperature of the sheet heater higher than the desired temperature.

[0005] However, until now, it was necessary to measure the outer surface temperatures of the sheet heater and the applied object multiple times to determine how much higher the temperature of the sheet heater needed to be than the desired temperature in order to adjust the outer surface temperature of the applied object to the desired temperature.

[0006] The present invention aims to solve the above-mentioned problems. That is, the present invention aims to provide a heater with a resistance temperature detector that has a low thermal conductor between the resistance temperature detector and the sheet heater and is installed on the outer surface of an installed object such as a pipe, and then, by applying electricity, when the resistance temperature detector is set to a desired temperature, the temperature of the outer surface of the installed object can also be set to a temperature close to the desired temperature, as well as a heated installed object including the heater and a heater installation method.

[0007] The present inventors have conducted extensive research to solve the above problems and have completed the present invention. The present invention comprises the following (1) to (13). (1) A heater with a resistance temperature detector, comprising a sheet heater and a resistance temperature detector, and further comprising a low thermal conductor between the sheet heater and the resistance temperature detector, the low thermal conductor having a thermal conductivity such that the difference (T1 - T2) between the temperature (T1) indicated by the resistance temperature detector and the outer surface temperature (T2) of the applied body during use is within ±3°C. (2) A heater with a resistance temperature detector as set forth in (1) above, in which the relationship between the difference (T3 - T1) between the outer surface temperature (T3) of the sheet heater and the temperature (T1) indicated by the resistance temperature detector during use and the thermal conductivity (κ) of the low thermal conductor satisfies the following formula (1): Formula (1): κ = -(1.8 x 10 -3 )×(T3-T1±3)+(5.7×10 －2 (3) The heater with a resistance temperature detector according to (1) or (2) above, wherein the relationship between the difference (T3-T2) between the outer surface temperature (T3) of the sheet heater and the outer surface temperature (T2) of the applied body during use and the thermal conductivity (κ) of the low thermal conductor satisfies the following formula (2): κ=-(1.8×10 -3 )×(T3-T2±3)+(5.7×10 －2(4) The heater with a resistance temperature detector according to any one of (1) to (3) above, wherein the thermal conductivity of the low thermal conductor at room temperature is 0.01 to 0.06 W / m K. (5) The heater with a resistance temperature detector according to any one of (2) to (4) above, wherein the difference (T3 - T1) between the outer surface temperature (T3) of the sheet heater and the temperature (T1) indicated by the resistance temperature detector during use is 2.5 to 20°C. (6) The heater with a resistance temperature detector according to any one of (3) to (5) above, wherein the difference (T3 - T2) between the outer surface temperature (T3) of the sheet heater and the outer surface temperature (T2) of the applied body during use is 2.5 to 20°C. (7) A heated body having a resistance temperature detector heater installed on the outer surface of the body, wherein the resistance temperature detector heater has a sheet heater, a low thermal conductor, and a resistance temperature detector, and the heater is installed on the outer surface of the body so that the sheet heater is closer to the body and the resistance temperature detector is farther from the body, with the low thermal conductor between them, and the low thermal conductor has a thermal conductivity such that the difference (T1 - T2) between the temperature (T1) indicated by the resistance temperature detector and the outer surface temperature (T2) of the body during use is within ±3°C. (8) A heated body according to (7) above, wherein the relationship between the difference (T3 - T1) between the outer surface temperature (T3) of the sheet heater and the temperature (T1) indicated by the resistance temperature detector during use and the thermal conductivity (κ) of the low thermal conductor satisfies the following formula (1): Formula (1): κ = -(1.8 x 10 -3 )×(T3-T1±3)+(5.7×10 －2 (9) The heater-equipped body according to (7) or (8), wherein the relationship between the difference (T3-T2) between the outer surface temperature (T3) of the sheet heater and the outer surface temperature (T2) of the body during use and the thermal conductivity (κ) of the low thermal conductor satisfies the following formula (2): κ=-(1.8×10 -3 )×(T3-T2±3)+(5.7×10 －2(10) A heater-equipped body according to (9) above, wherein the difference (T3-T2) between the outer surface temperature (T3) of the sheet heater and the outer surface temperature (T2) of the body during use is 2.5 to 20°C. (11) A heater installation method for installing a heater with a resistance temperature detector, which includes a sheet heater, a low thermal conductor, and a resistance temperature detector, on the outer surface of an application body, comprising: a temperature measurement step of installing the sheet heater on the outer surface of the application body, adjusting the sheet heater to a temperature during use, and then measuring the outer surface temperature (T3) of the sheet heater and the outer surface temperature (T2) of the application body; and an adjustment step of selecting the low thermal conductor having a thermal conductivity such that the difference (T1-T2) between the temperature (T1) indicated by the resistance temperature detector and the outer surface temperature (T2) of the application body is within ±3°C, using a previously determined relational expression (T3-T2) between the outer surface temperature (T3) of the sheet heater and the outer surface temperature (T2) of the application body and the thermal conductivity (κ) of the low thermal conductor. and an installation step of installing the heater with a resistance temperature detector on the outer surface of the body to be installed so that the sheet heater is on the side closer to the body to be installed, the resistance temperature detector is on the side farther from the body to be installed, and the low thermal conductor selected in the adjustment step is between them. (12) The heater installation method according to (11) above, wherein the relationship between the difference (T3 - T2) between the outer surface temperature (T3) of the sheet heater and the outer surface temperature (T2) of the body to be installed, which is determined in advance in the adjustment step, and the thermal conductivity (κ) of the low thermal conductor is the following equation (2): Equation (2): κ = -(1.8 x 10 -3 )×(T3-T2±3)+(5.7×10 －2 (13) The heater installation method according to (11) or (12) above, wherein the relationship between the difference (T3-T1) between the outer surface temperature (T3) of the sheet heater and the temperature (T1) indicated by the resistance temperature detector when the heater with resistance temperature detector is in use and the thermal conductivity (κ) of the low thermal conductor satisfies the following formula (1): Formula (1): κ=-(1.8×10 -3 )×(T3-T1±3)+(5.7×10 －2 (14) A heater installation method according to any one of (11) to (13) above, wherein the object to be installed is a pipe.

[0008] According to the present invention, a heater with a resistance thermometer sensor having a low thermal conductor between the resistance thermometer sensor and a sheet-type heater is installed on the outer surface of an installation body such as a pipe, and then by passing electricity through it, when the resistance thermometer sensor is set to a desired temperature, the outer surface temperature of the installation body can also be set to a temperature close to the desired temperature, as well as an installation body with a heater including the same and a heater installation method can be provided.

[0009] FIG. 1 is a schematic perspective view showing a heater of the present invention installed on the outer surface of an application body (pipe-shaped piping having a circular cross section). FIG. 2 is a schematic perspective view showing a heater of the present invention installed on the outer surface of an application body (pipe-shaped piping having a substantially rectangular cross section). FIG. 3 is a cross-sectional view (schematic perspective view) of the application body and sheet-type heater when cut in a direction perpendicular to the main surface of the sheet-type heater. FIG. 4 is a cross-sectional view (schematic perspective view) of a heater-equipped application body of the present invention when cut in a direction perpendicular to the main surface of the sheet-type heater. FIG. 5 is a graph showing the relationship obtained in the examples (the relationship between the difference (T3-T2) between the outer surface temperature (T3) of the sheet-type heater and the outer surface temperature (T2) of the application body, and the thermal conductivity (κ) of the low thermal conductor).

[0010] The present invention will be described. The present invention is a heater with a resistance temperature detector, which includes a sheet heater and a resistance temperature detector, and further includes a low thermal conductor between the sheet heater and the resistance temperature detector, the low thermal conductor having a thermal conductivity such that the difference (T1 - T2) between the temperature (T1) indicated by the resistance temperature detector and the outer surface temperature (T2) of the applied body during use is within ±3°C. Such a heater with a resistance temperature detector will be referred to hereinafter as the "heater of the present invention."

[0011] The present invention also provides a heated body comprising a resistance temperature detector-equipped heater installed on the outer surface of the body, the resistance temperature detector having a sheet heater, a low thermal conductor, and a resistance temperature detector. The heater is installed on the outer surface of the body so that the sheet heater is closer to the body and the resistance temperature detector is farther away, with the low thermal conductor between them. The low thermal conductor has a thermal conductivity such that the difference (T1 - T2) between the temperature (T1) indicated by the resistance temperature detector during use and the outer surface temperature (T2) of the body is within ±3°C. Such a heated body is hereinafter also referred to as the "heated body of the present invention." T1 - T2 is preferably within ±2°C, and more preferably within ±1.5°C. Having T1 - T2 within this range contributes to the temperature uniformity of the body. In the present invention, a temperature close to a desired temperature refers to a temperature within ±3°C of the desired temperature.

[0012] Furthermore, the present invention provides a heater installation method for installing a heater with a resistance temperature detector, which includes a sheet heater, a low thermal conductor, and a resistance temperature detector, on the outer surface of an installation body, the method comprising the steps of: installing the sheet heater on the outer surface of the installation body; adjusting the sheet heater to a temperature during use; and measuring the outer surface temperature (T3) of the sheet heater and the outer surface temperature (T2) of the installation body; and calculating a difference (T3-T2) between the outer surface temperature (T3) of the sheet heater and the outer surface temperature (T2) of the installation body, which is previously determined. This heater installation method includes an adjustment step of selecting a low thermal conductor having a thermal conductivity such that the difference (T1-T2) between the temperature (T1) indicated by the resistance temperature detector and the outer surface temperature (T2) of the application body is within ±3°C using a relational expression with the thermal conductivity (κ) of the low thermal conductor, and an installation step of installing the heater with resistance temperature detector on the outer surface of the application body so that the sheet heater is closer to the application body, the resistance temperature detector is farther from the application body, and the low thermal conductor selected in the adjustment step is located between them. This heater installation method will be referred to hereinafter as the "method of the present invention."

[0013] Hereinafter, when simply referring to "the present invention," it means any of the heater of the present invention, the heater-equipped body of the present invention, and the method of the present invention.

[0014] An overview of the present invention will be explained using Fig. 1. Fig. 1 is a schematic perspective view showing a heater 5 of the present invention installed on the outer surface of an application body 1. Specifically, the figure shows a sheet-type heater 2 installed on the outer surface of the application body 1, a low thermal conductor 3 installed on the outer surface of that, and a resistance temperature detector 4 installed on the outer surface of that.

[0015] In the present invention, the direction away from the construction body 1 is the outside, and the main surface that is on the outside of each part is the outer surface. The main surface opposite the outer surface is the inner surface.

[0016] 1, the heater 5 of the present invention is a portion consisting of the sheet heater 2, the low thermal conductor 3, and the resistance temperature detector 4. The heater 5 of the present invention installed on the outer surface of the work 1 is the heated work 10 of the present invention.

[0017] In Fig. 1, the construction body 1 is a metal pipe-like piping. In the present invention, the construction body 1 itself (including the interior of the construction body) is the object to be heated, and it is sufficient that the object to be heated can be heated by a sheet-like heater installed on the outer surface. In the present invention, the construction body may be, in addition to the piping shown in Fig. 1, for example, a planar construction body, a bellows piping, an elbow piping, etc.

[0018] The shape, size, material, etc. of the construction body 1 are not particularly limited. The construction body 1 shown in Fig. 1 is a metal pipe-like piping, and its cross section perpendicular to the longitudinal direction is circular, but as shown in Fig. 2, it may also be a pipe-like piping with a substantially rectangular cross section. When the construction body 1 is the piping shown in Figs. 1 and 2, it may have a length of, for example, 10 to 3000 mm, and a cross-sectional diameter (equivalent diameter of a circle with equal area) of 5 to 200 mm. The material of the construction body 1 is preferably metal, but may also be resin or ceramic.

[0019] In the embodiment shown in FIG. 2 , the outer surface of the application body 1′ (pipe) is uneven, making it difficult to closely attach the sheet-type heater 2′ to the outer surface of the application body 1′. In such cases, it is preferable to place a member 7 (e.g., a metal plate such as aluminum) with high thermal conductivity in the recessed portion of the outer surface of the application body 1′, as shown in FIG. 2 . It is preferable that such member 7 be in contact with both the outer surface of the application body 1′ and the inner surface of the sheet-type heater 2′. In this case, the sheet-type heater 2′ is installed so as to be in contact with the outer surface of the application body 1′ and the outer surface of member 7, and a low thermal conductor 3′ is installed on its outer surface, and a resistance temperature detector 4′ is installed on its outer surface, forming the heater 5′ of the present invention. Furthermore, the heater 5′ of the present invention installed on the outer surface of the application body 1′ (including member 7) is the heated application body 10′ of the present invention.

[0020] The low thermal conductor has a specific thermal conductivity, which is affected by factors such as the amount of gap between the sheet heater and the outer surface of the application body, as will be explained in detail later.

[0021] The low thermal conductor may be a PTFE fiber sheet, a silicone sheet, ceramic paper, an aerogel sheet, glass wool, or the like.

[0022] The low thermal conductor is preferably fixed to the outer surface of the sheet heater. There are no particular limitations on the method for fixing the low thermal conductor to the outer surface of the sheet heater, but it can be fixed using, for example, a conventionally known double-sided tape.

[0023] The shape, size, etc. of the low thermal conductor are not particularly limited, but it is necessary that the shape, size, etc. be such that the resistance temperature detector does not come into direct contact with the sheet heater.

[0024] A resistance temperature detector determines temperature by utilizing the property of metals or metal oxides that their electrical resistance changes with temperature. By using a resistance temperature detector as a sensor and combining it with a conventionally known temperature regulator, the temperature of a sheet heater can be controlled to a desired temperature.

[0025] In the present invention, a conventionally known resistance temperature detector can be used, for example, a resistance temperature detector using platinum.

[0026] The sheet heater may include a heat-generating layer that generates heat when electricity is applied. The sheet heater may be the heat-generating layer itself. The sheet heater may be a laminate formed by laminating an insulating layer, a heat-generating layer, and an insulating layer in this order. The sheet heater may also be a laminate further including a heat-insulating layer. When the sheet heater is disposed on the outer surface of the applied body, it is preferable to dispose the sheet heater so that the insulating layer is located closer to the outer surface of the applied body. The sheet heater may also be a laminate further including a thermal diffusion layer. When the sheet heater has a thermal diffusion layer, it is preferable to dispose the sheet heater so that the thermal diffusion layer is located closer to the outer surface of the applied body.

[0027] The insulating layer, the heat generating layer, the heat insulating layer and the thermal diffusion layer are each in a sheet form, and a laminate formed by adhering the main surfaces of two or more of these, including the heat generating layer, to each other can be made into a sheet heater.

[0028] <Heat-generating layer> The heat-generating layer is preferably disposed on the outer side of the insulating layer when viewed from the application body. The heat-generating layer is not particularly limited as long as it generates heat when an electric current is applied after attaching a sheet heater to the outer surface of the application body (other objects may be present between the sheet heater and the outer surface of the application body; the same applies below), and can apply heat to the application body itself or the inside of the application body.

[0029] The material of the heat generating layer is preferably stainless steel (for example, SUS304, SUS316, SUS316L), but may also be copper (Cu), aluminum (Al), nickel (Ni), nichrome, or carbon.

[0030] The heat generating layer is preferably made of a fibrous material, such as a metal mesh in the form of a sheet in which linear fibers are arranged substantially perpendicular to one another, a metal fiber nonwoven fabric in which metal fibers are arranged randomly, a metal fiber woven fabric, linear metal fibers, or tape-like metal fibers.

[0031] Here, the metal mesh may be, for example, a metal mesh of 200 to 500 mesh. The metal fiber nonwoven fabric may be, for example, a metal mesh of 1500 g / m 2Examples of suitable metal fiber woven fabrics include stainless steel fiber nonwoven fabrics (SUS316L needle punch web, manufactured by Nikko Techno Co., Ltd.). Examples of suitable metal fiber woven fabrics include SUS cloth (Naslon Cloth A, manufactured by Nippon Seisen Co., Ltd.). Examples of suitable linear metal fibers include filament yarn (Naslon 12-2000 / 3, manufactured by Nippon Seisen Co., Ltd.). Examples of suitable tape-shaped metal fibers include SUS tape (Naslon Tape B W16, manufactured by Nippon Seisen Co., Ltd.).

[0032] The thickness of the heat generating layer is preferably 10 to 600 μm, more preferably 20 to 150 μm, and from the viewpoint of flexibility and strength, preferably about 30 μm.

[0033] The shape and size of the main surface of the heat generating layer can be adjusted appropriately to match the size of the outer surface of the workpiece to which heat is applied.

[0034] The heat generating layer preferably has a specific electric resistance of 5 to 3000 μΩcm, more preferably 10 to 2500 μΩcm, where the specific electric resistance is determined in accordance with JIS K 7194.

[0035] The heat generating layer is preferably composed mainly of metal fibers, and more preferably composed only of metal fibers. Here, "mainly" means 70% by mass or more. In other words, the heat generating layer is preferably composed of 70% by mass or more of metal fibers. The proportion of metal fibers contained in the heat generating layer is more preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more. Furthermore, "composed only of metal fibers" means that 98% by mass or more of the metal fibers are metal fibers. By setting the proportion of metal fibers in the heat generating layer as described above, the heat generating layer 7 can fully exhibit its electrical conductivity and heat generating properties.

[0036] The proportion of metal fibers contained in the heating layer is determined by the following method: In an SEM image obtained by magnifying the surface of the heating layer by 1,000 times using a scanning electron microscope (SEM), the area of ​​all components within the field of view is determined using an image processing device, converted to a volume ratio by raising it to the power of 2 / 3, and then multiplied by the specific gravity to determine a mass ratio, thereby calculating the metal fiber content. If two or more types of metal fibers are contained, the content of each metal fiber is determined and the total value is used as the proportion of metal fibers contained in the heating layer.

[0037] The metal fibers are preferably metallic fibers having a cross-sectional equivalent circle diameter of 2 to 100 μm (preferably 5 to 20 μm) and a length of 2 to 20 mm. In an SEM image of the metal fiber obtained at 1000x magnification using a scanning electron microscope (SEM), 30 cross sections of the metal fiber are randomly selected from the image, the cross-sectional area (cross-sectional area) of the metal fiber is determined at each location, and the simple average is calculated. The average cross-sectional area is then used to calculate the cross-sectional equivalent circle diameter of the metal fiber. The heat-generating layer is preferably a sheet-like structure (metal fiber sheet) in which countless metallic fibers are intricately entangled. The metal fiber sheet may be composed solely of metal fibers, but may also contain other materials (e.g., resin fibers that function as binders) as long as they do not interfere with heat generation. Examples of binders include carbon, glass, and silicone resin. The metal fibers constituting the metal fiber sheet are in contact with each other to the extent that they are electrically conductive. It is preferable that the metal fibers are connected to each other at their contact points. For example, it is preferable that the metal fibers are fused to each other at their contact points by having a history of melting some of the metal fibers by sintering at a high temperature and then solidifying.

[0038] The metal fiber sheet is preferably a stainless steel fiber sheet due to its high heat resistance and chemical resistance. Examples of the stainless steel fiber sheet include a stainless steel fiber sheet (for example, Tommyfirec SS, manufactured by Tomoegawa Corporation).

[0039] The metal fiber sheet has a basis weight of 25 g / m 2It is preferable that the weight is 50 g / m or more. 2 It is preferable that the density is 1000 g / m or more. 2 It is preferable that the weight is 200 g / m or less. 2 It is more preferable that the basis weight of the metal fiber sheet is less than or equal to 100%. When the basis weight of the metal fiber sheet is within this range, the strength of the metal fiber sheet can be ensured and the contact points between the metal fibers can be made relatively uniform, so that the flexibility of the sheet heater of the present invention can be ensured and the strength of the heating layer can also be ensured. The basis weight is a value determined in accordance with JIS P 8124.

[0040] The thickness of the metal fiber sheet is preferably 10 to 600 μm, more preferably 20 to 150 μm, and from the viewpoint of flexibility and strength, preferably about 30 μm.

[0041] The density of the metal fiber sheet is 1.0 to 5.0 g / cm 3 is preferably 1.4 to 2.0 g / cm 3 More preferably, it is 1.7 g / cm 3 The density of the metal fiber sheet is preferably about 1 / 2 of the density (g / cm 3 ) in accordance with JIS P 8118. 3 )=Basic weight (g / m 2 ) / thickness (mm) × 1000. When the density of the metal fiber sheet is within this range, the strength of the metal fiber sheet can be ensured, and the contact points between the metal fibers can be made relatively uniform, so the strength of the heating layer can also be ensured.

[0042] Metal fiber sheets can be manufactured by either a dry nonwoven fabric manufacturing method or a wet papermaking method. When manufactured by the wet papermaking method, numerous metallic fibers having a cross-sectional equivalent circle diameter of 2 to 100 μm and a length of 2 to 20 mm are stirred in a dispersion medium (water, organic solvent, etc.), and then an organic flocculant is added, and the mixture is formed into a sheet using a rectangular hand-made sheeting machine (manufactured by Toyo Seiki Co., Ltd., etc.), and the sheet is dried using a ferrotype dryer to a basis weight of 50 to 1100 g / m. 2A dried sheet of the above is obtained. Then, the sheet is fired at 400 to 1300° C. to obtain a metal fiber sheet. In principle, it is preferable that no organic flocculant remains in the metal fiber sheet.

[0043] <Insulating layer> When the sheet heater is attached to the outer surface of the application body, the insulating layer serves to electrically insulate the heating layer from the application body. Therefore, it is preferable that the insulating layer be made of a material with high insulating properties. Furthermore, if the sheet heater does not have a thermal diffusion layer, it is preferable that the insulating layer have thermal conductivity in addition to insulation properties.

[0044] The insulating layer is preferably made of, for example, PET (polyethylene terephthalate), PI (polyimide), PP (polypropylene), PE (polyethylene), PEN (polyethylene naphthalate), TAC (triacetyl cellulose), ceramic, etc., because these have high insulating properties. Among these, an insulating layer made of PI (polyimide) is preferred because of its excellent heat resistance and insulating properties.

[0045] The thickness of the insulating layer is not particularly limited, but is preferably 10 to 700 μm, more preferably 20 to 600 μm, and even more preferably 25 to 500 μm.

[0046] Here, the thickness of the insulating layer is determined by cutting the sheet heater in a direction perpendicular to its main surface, taking an enlarged photograph (200x magnification) of the cross section, measuring the thickness of the insulating layer at 100 randomly selected points on the enlarged photograph of the cross section, and calculating the simple average value of the measurements. The obtained average value is the thickness of the insulating layer.

[0047] The thickness of other layers (except the heat insulating layer described below) included in the sheet heater also means a value obtained by measuring using the same method as for the insulating layer.

[0048] The shape and size of the main surface of the insulating layer are not particularly limited. However, since the insulating layer serves to electrically insulate the heating layer from the application body when the sheet heater is attached to the outer surface of the application body, the size of the main surface of the insulating layer is usually the same as or larger than the main surface of the heating layer. Furthermore, the shape of the main surface of the insulating layer may usually be the same as or similar to the main surface of the heating layer.

[0049] <Thermal Insulation Layer> The thermal insulation layer is preferably disposed outside the insulating layer, which is located outside the heat generating layer as viewed from the construction body, in order to prevent heat leakage.

[0050] Examples of insulating materials that make up the insulating layer include fiber-based insulating materials (glass wool, rock wool, cellulose fiber, wool breath, etc.) and foam-based insulating materials (urethane foam, phenol foam, melamine foam, Teflon foam, polyimide foam, etc.).

[0051] The thickness of the heat insulating layer is not particularly limited, but is preferably 15 to 100,000 μm, more preferably 30 to 50,000 μm, and even more preferably 6,000 to 10,000 μm. The thickness of the heat insulating layer is measured at 30 points using a vernier caliper and the value obtained by simply averaging the measurements (average value).

[0052] The main surface of the heat insulating layer is usually larger than the main surface of the heat generating layer.

[0053] The heat insulating layer is disposed on the outside of the insulating layer, which is located on the outside of the heat generating layer, but it is preferable that the main surface (inner surface) of the heat insulating layer is not adhered to the main surface (outer surface) of the insulating layer. From the viewpoint of improving workability during installation and enabling easy removal of the heat insulating layer and the insulating layer after installation, it is preferable to partially secure the heat insulating layer and the insulating layer by sewing a part of them together, or to secure them with Velcro or buttons, etc. In this case, air is more likely to be present between the heat insulating layer and the insulating layer, which is expected to have the effect of further improving the heat insulating properties.

[0054] <Thermal diffusion layer> The sheet heater preferably further has a thermal diffusion layer between the installation body and the insulating layer. When the sheet heater further has a thermal diffusion layer, the heat generated by the heat generating layer can be diffused, and the outer surface of the pipe can be heated more uniformly.

[0055] The thermal conductivity of the thermal diffusion layer in its in-plane direction is preferably higher than that of the heat-generating layer in its in-plane direction. This is because the thermal diffusion ability is further enhanced. The thermal conductivity of the thermal diffusion layer is measured at room temperature using a known measurement method, such as a laser flash thermal diffusivity measurement (e.g., the LFA series manufactured by NETZSCH) or an optical AC thermal diffusivity measurement (e.g., the LaserPit series manufactured by Advance Riko).

[0056] The thermal diffusion layer is preferably made of a metal such as carbon, aluminum, copper, zinc, lead, gold, silver or alumina, or a ceramic such as aluminum nitride.

[0057] The thermal diffusion layer is preferably made of a carbon film, as this has excellent flexibility and high thermal conductivity in the extending direction.

[0058] It is also preferable that the thermal diffusion layer is made of a carbon film and the heat generating layer is made of an SUS fiber sheet, since this can avoid the effects of electrolytic corrosion that often occurs between metals during long-term use.

[0059] The thickness of the thermal diffusion layer is not particularly limited, but is preferably 5 to 300 μm, more preferably 15 to 200 μm, and even more preferably about 200 μm.

[0060] According to the heater of the present invention, the entire surface of the workpiece, such as a pipe, can be uniformly heated.

[0061] <Method of the Present Invention> The method of the present invention will be described with reference to the drawings. The method of the present invention is a heater installation method in which a heater with a resistance temperature detector, which includes a sheet heater, a low thermal conductor, and a resistance temperature detector as described above, is installed on the outer surface of an object to be installed.

[0062] The method of the present invention comprises a temperature measurement process, an adjustment process, and an application process. It is necessary to prepare a graph in advance to determine the thermal conductivity required for the low thermal conductor in the adjustment process. Therefore, we will first explain the graph creation process, which is the pre-process, and then explain the method of the present invention. It is not necessary to create a graph before carrying out the method of the present invention; once a graph is created, the graph creation process is not necessary the next time.

[0063] <Graph Creation Process> The graph creation process is a process for creating a graph showing the relationship between the difference (T3-T2) between the outer surface temperature (T3) of the sheet heater and the outer surface temperature (T2) of the applied body and the thermal conductivity in order to determine the thermal conductivity required for the low thermal conductor in the adjustment process of the method of the present invention.Once this graph has been created, it will not be necessary the next time the present invention is carried out.

[0064] FIG. 3 is a cross-sectional view (schematic perspective view) of the heater and sheet heater cut perpendicular to the main surface of the heater. In the graph creation process, the heater 22 is first installed on the outer surface of the heater 20, as shown in FIG. 3. Although not shown, a resistance temperature detector is installed on the outer surface of the heater. The resistance temperature detector is used as a sensor and can be combined with a conventionally known temperature regulator to adjust the temperature of the heater. The resistance temperature detector is then adjusted to the desired operating temperature. The operating temperature is determined by the desired temperature of the heater 20. After temperature adjustment, the temperature of the resistance temperature detector will be approximately equal to the temperature of the heater. The outer surface temperature (T3) of the heater 22 and the outer surface temperature (T2) of the heater 20 are then measured, and the difference (T3 - T2) is calculated.

[0065] There is no particular limitation on the method for measuring the outer surface temperature (T3) of the sheet-shaped heater 22. For example, the outer surface temperature (T3) can be measured by disposing a thermocouple on the outer surface of the sheet-shaped heater 22 or by using a radiation thermometer.

[0066] In addition, the method for measuring the outer surface temperature (T2) of the application body 20 is not particularly limited. For example, the outer surface temperature (T2) can be measured by placing a thermocouple between the outer surface of the application body 20 and the inner surface of the sheet-like heater 22, or by using a radiation thermometer.

[0067] Next, using the same applied body and sheet heater used to obtain T3-T2, a resistance temperature detector 27 is installed on the outer surface of the sheet heater 23 via a low thermal conductor 25 having an arbitrary thermal conductivity, as shown in Figure 4. The resistance temperature detector 27 is used as a sensor, and the temperature of the resistance temperature detector 27 can be adjusted in combination with a conventionally known temperature regulator.

[0068] After installation, the resistance temperature detector 27 is adjusted to the desired temperature during use. The low thermal conductor 25 is then adjusted while measuring the temperatures T1 and T2 so that the difference (T1-T2) between the temperature (T1) indicated by the resistance temperature detector 27 and the outer surface temperature (T2) of the construction body 21 is within ±3°C. When T1-T2 is within ±3°C, the thermal conductivity of the low thermal conductor alone is measured at room temperature using a known measurement method, such as laser flash thermal diffusivity measurement (e.g., the LFA series manufactured by NETZSCH) or optical AC thermal diffusivity measurement (e.g., the LaserPit series manufactured by Advance Riko). Specific methods for adjusting the thermal conductivity of the low thermal conductor 25 include stacking multiple low thermal conductors using double-sided tape or changing the type of low thermal conductor.

[0069] After obtaining the values ​​of T3 - T2 and thermal conductivity, the desired operating temperature of the resistance thermometer is changed and the above procedure is repeated to obtain another value of T3 - T2 and thermal conductivity. By repeating this procedure, multiple values ​​of T3 - T2 and thermal conductivity can be obtained. By plotting these values ​​with T3 - T2 on the X axis and thermal conductivity (κ) on the Y axis, a graph showing the relationship between T3 - T2 and the thermal conductivity (κ) of the low thermal conductor can be created, as shown in Figure 5, for example. This graph is processed using the least squares method to calculate, for example, the slope and intercept of a linear function. By inputting the calculated slope and intercept into the equation κ = a(T3 - T2 ± 3) + b, where a is the slope and b is the intercept, it is possible to obtain, for example, equation (2) of the present invention: κ = -(1.8 x 10 -3 )×(T3-T2±3)+(5.7×10 －2 ) can be obtained. Furthermore, since T1-T2 is within ±3°C, the following relational expression can be obtained: κ = -(1.8 × 10 -3 )×(T3-T1±3)+(5.7×10 －2) also holds. The relational expression does not have to be a linear function, and may be an expression other than expression (2).

[0070] The graph created in the graph creation process was based on the discovery that the approximate agreement between the temperature (T1) indicated by the resistance temperature detector and the outer surface temperature (T2) of the object being treated (i.e., a temperature close to the desired temperature) depends on the thermal conductivity of the low thermal conductor. Additionally, the thermal conductivity of the low thermal conductor when the temperature (T1) indicated by the resistance temperature detector and the outer surface temperature (T2) of the object being treated can be approximately equalized is correlated with T3 - T2. By creating such a graph in advance, the thermal conductivity value of the low thermal conductor can be determined from the T3 - T2 value obtained in the temperature measurement process of the present invention, for example, using the relationship between T3 - T2 and the thermal conductivity (κ) of the low thermal conductor, as shown in Figure 5. In other words, by using a low thermal conductor having this thermal conductivity value, the temperature (T1) indicated by the resistance temperature detector and the outer surface temperature (T2) of the object being treated can be approximately equalized. Specifically, the difference (T1-T2) between the temperature (T1) indicated by the resistance thermometer and the outer surface temperature (T2) of the workpiece can be kept within ±3°C.

[0071] <Temperature Measurement Process> In the temperature measurement process, as shown in FIG. 3, a sheet-type heater 22 is installed on the outer surface of the heater 20. Although not shown, a resistance temperature detector is installed on the outer surface of the heater. The resistance temperature detector is used as a sensor and can be combined with a conventionally known temperature regulator to adjust the temperature of the heater. Next, the resistance temperature detector is adjusted to the temperature during use. The temperature during use is determined by the desired temperature of the heater 20. For example, if the desired temperature of the heater 20 is 100°C, the temperature measurement process involves applying electricity to the heating layer of the heater so that the outer surface temperature (T3) of the heater is 100°C or close to this temperature, thereby adjusting the temperature of the resistance temperature detector. After the temperature adjustment, the temperature of the resistance temperature detector will be approximately the same as the temperature of the heater 22.

[0072] After the outer surface temperature (T3) of the sheet heater reaches the desired temperature (preferably after the temperature has stabilized), the outer surface temperature (T2) of the application body 20 is measured.

[0073] From the thus determined T3 and T2, the difference between them (T3-T2) can be calculated.

[0074] <Adjustment Process> FIG. 4 is a cross-sectional view (schematic perspective view) of the heater-equipped structure of the present invention cut in a direction perpendicular to the main surface of the sheet heater.

[0075] As shown in Figure 4, in a heater-equipped construction 30 of the present invention, a resistance temperature detector 27 is installed on the outer surface of a sheet-type heater 23 via a low thermal conductor 25. The resistance temperature detector 27 is used as a sensor, and the temperature of the resistance temperature detector 27 can be adjusted by combining it with a conventionally known temperature regulator. Because the low thermal conductor 25 is present between the sheet-type heater 23 and the resistance temperature detector 27, the actual outer surface temperature (T3) of the sheet-type heater 23 is higher than the temperature (T1) indicated by the resistance temperature detector 27. Alternatively, if the amount of current flowing through the sheet-type heater 23 is controlled so that the resistance temperature detector 27 reaches a predetermined temperature, the actual outer surface temperature (T3) of the sheet-type heater 23 will be higher than the predetermined temperature.

[0076] On the other hand, the outer surface temperature (T2) of the application body 21 tends to be lower than the outer surface temperature (T3) of the sheet-type heater 23. The inventors believe that this is mainly due to the occurrence of a gap between the sheet-type heater 23 and the outer surface of the application body 21.

[0077] In the adjustment step, a low thermal conductor is selected using the relational expression previously determined in the graphing step. The relational expression, such as that shown in FIG. 5, expresses the relationship between the difference (T3-T2) between the outer surface temperature (T3) of the sheet heater and the outer surface temperature (T2) of the workpiece, and the thermal conductivity (κ) of the low thermal conductor. Using this relational expression, a low thermal conductor is selected that has a thermal conductivity (e.g., the y-value of the linear function shown in FIG. 5) such that the difference (T1-T2) between the temperature (T1) indicated by the resistance temperature detector and the outer surface temperature (T2) of the workpiece is within ±3°C, based on T3-T2 obtained in the temperature measurement step.

[0078] <Installation process> In the installation process, a low thermal conductor with a specific thermal conductivity selected as described above is used. Then, a heater with a resistance temperature detector is installed on the outer surface of the installation body so that a sheet heater is located on the side closest to the installation body, a resistance temperature detector is located on the side farther away, and the low thermal conductor selected in the adjustment process is located between them. A temperature regulator is attached to the resistance temperature detector.

[0079] <Heater of the Present Invention> The heater of the present invention is a heater with a resistance temperature detector, comprising a sheet-type heater and a resistance temperature detector as described above, and further comprising a low thermal conductor between the sheet-type heater and the resistance temperature detector. The low thermal conductor has a thermal conductivity such that the difference (T1 - T2) between the temperature (T1) indicated by the resistance temperature detector and the outer surface temperature (T2) of the applied body during use is within ±3°C. By the method described in the adjustment step of the method of the present invention, a low thermal conductor with a thermal conductivity such that T1 - T2 is within ±3°C can be selected.

[0080] In the heater of the present invention, it is preferable that the relationship between the difference (T3-T1) between the outer surface temperature (T3) of the sheet heater during use and the temperature (T1) indicated by the resistance temperature detector, and the thermal conductivity (κ) of the low thermal conductor, satisfies the following formula (1): Formula (1): κ=-(1.8×10 -3 )×(T3-T1±3)+(5.7×10 －2 )

[0081] In the heater of the present invention, it is preferable that the relationship between the difference (T3-T2) between the outer surface temperature (T3) of the sheet heater and the outer surface temperature (T2) of the applied body during use and the thermal conductivity (κ) of the low thermal conductor satisfies the following formula (2): κ=-(1.8×10 -3 )×(T3-T2±3)+(5.7×10 －2 )

[0082] In the heater of the present invention, it is preferable that the thermal conductivity of the low thermal conductor at room temperature is 0.01 to 0.06 W / m·K.

[0083] In the heater of the present invention, it is preferable that the difference (T3-T1) between the outer surface temperature (T3) of the sheet heater and the temperature (T1) indicated by the resistance temperature detector during use is 2.5 to 20°C.

[0084] In the heater of the present invention, it is preferable that the difference (T3-T2) between the outer surface temperature (T3) of the sheet heater and the outer surface temperature (T2) of the applied body during use is 2.5 to 20°C.

[0085] <Heated Body of the Present Invention> The heated body of the present invention is a heated body comprising a heater with a resistance temperature detector as described above, installed on the outer surface of the body. The heater with a resistance temperature detector includes a sheet heater, a low thermal conductor, and a resistance temperature detector, and the heater with a resistance temperature detector is installed on the outer surface of the body so that the sheet heater is closer to the body and the resistance temperature detector is farther from the body, with the low thermal conductor between them. The low thermal conductor has a thermal conductivity such that the difference (T1 - T2) between the temperature (T1) indicated by the resistance temperature detector during use and the outer surface temperature (T2) of the body is within ±3°C. A low thermal conductor with a thermal conductivity such that T1 - T2 is within ±3°C can be selected by the method described in the adjustment step of the method of the present invention.

[0086] In the heater-equipped structure of the present invention, it is preferable that the relationship between the difference (T3-T1) between the outer surface temperature (T3) of the sheet heater during use and the temperature (T1) indicated by the resistance temperature detector, and the thermal conductivity (κ) of the low thermal conductor, satisfies the following formula (1): Formula (1): κ=-(1.8×10 -3 )×(T3-T1±3)+(5.7×10 －2 )

[0087] In the heater-equipped body of the present invention, it is preferable that the relationship between the difference (T3-T2) between the outer surface temperature (T3) of the sheet heater and the outer surface temperature (T2) of the body during use and the thermal conductivity (κ) of the low thermal conductor satisfies the following formula (2): κ = -(1.8 x 10 -3 )×(T3-T2±3)+(5.7×10 －2 )

[0088] In the heater-equipped application body of the present invention, it is preferable that the difference (T3-T2) between the outer surface temperature (T3) of the sheet heater and the outer surface temperature (T2) of the application body during use is 2.5 to 20°C.

[0089] The present invention will be specifically described below with reference to examples, but the present invention is not limited to the examples described below.

[0090] 1. Graph Creation Step An experiment was conducted to determine in advance the relationship equation (the relationship equation between the difference (T3-T2) between the outer surface temperature of the sheet heater (T3) and the outer surface temperature of the applied body (T2) and the thermal conductivity (κ) of the low thermal conductor) to be used in the adjustment step of the method of the present invention. That is, the graph creation step was first performed.

[0091] First, a heat generating layer was prepared with insulating layers attached to both main surfaces. The heat generating layer was made of SUS paper (SUS316L, thickness: 30 μm), and the insulating layer was made of PI film (Kapton 100EN (manufactured by DuPont-Toray Co., Ltd.), thickness: 25 μm). Using these, a laminate (sheet-shaped heater) was produced in which a first insulating layer, a heat generating layer, and a second insulating layer were laminated in this order.

[0092] Next, a resistance temperature detector was installed on the outer surface of the sheet heater. A platinum sensor with a measurement range of -200 to 660°C was used as the resistance temperature detector. The sheet heater was attached to the resistance temperature detector using double-sided tape (Kapton (registered trademark) 760H, manufactured by Teraoka Seisakusho Co., Ltd.) to create a heater with a resistance temperature detector without a low thermal conductor. A temperature regulator was attached to the resistance temperature detector. The heater with a resistance temperature detector without a low thermal conductor was then attached to the outer surface of the applied body. The first insulating layer of the sheet heater was attached to the surface of the applied body. Next, electricity was applied to the heating layer, and the resistance temperature detector was adjusted to the desired temperature. A thermocouple was installed on the outer surface of the second insulating layer, and the outer surface temperature (T3) of the sheet heater was measured. A thermocouple was also installed on the outer surface of the applied body, and its outer surface temperature (T2) was measured. After the adjusted temperature stabilized, the temperature difference (T3 - T2) was calculated.

[0093] Next, a PTFE fiber sheet (Tomyfirec PA-5LH, manufactured by Tomoegawa Corporation, thickness: 480 μm) and double-sided tape (Kapton (registered trademark) 760H, manufactured by Teraoka Seisakusho Co., Ltd.)) were used, and the ratio of their amounts (layering amounts) was changed to obtain low thermal conductors with various thermal conductivities. That is, a PTFE fiber sheet can be bonded to another PTFE fiber sheet using double-sided tape, and by adjusting the number of double-sided tapes used or the number of layers of PTFE fiber sheets, low thermal conductors with various thermal conductivities can be obtained.

[0094] Next, the sheet heater fabricated as described above was prepared, and a resistance temperature detector was installed on the outer surface of the second insulating layer of this sheet heater via one of the low thermal conductors obtained above. A platinum sensor with a measurement range of -200 to 660°C was used as the resistance temperature detector. The sheet heater and the low thermal conductor were attached to each other using double-sided tape (Kapton (registered trademark) 760H, manufactured by Teraoka Seisakusho Co., Ltd.). A temperature controller was attached to the resistance temperature detector.

[0095] Next, electricity was applied to the heating layer, and the resistance thermometer was adjusted to the desired temperature. It was then confirmed whether the difference (T1 - T2) between the temperature (T1) indicated by the resistance thermometer and the outer surface temperature (T2) of the applied body was within ±3°C. If this was not the case, the installed low thermal conductor was replaced with the low thermal conductor obtained above, and the optimal low thermal conductor was found to achieve T1 - T2 within ±3°C. The thermal conductivity of the low thermal conductor alone when T1 - T2 was within ±3°C was measured at room temperature using a laser flash thermal diffusivity meter (NETZSCH LFA series).

[0096] After obtaining the values ​​of T3 - T2 and thermal conductivity, the desired operating temperature of the resistance thermometer sensor is changed and the above procedure is repeated to obtain another value of T3 - T2 and thermal conductivity. By repeating this procedure, multiple values ​​of T3 - T2 and thermal conductivity are obtained. These values ​​are plotted with T3 - T2 on the X axis and thermal conductivity (κ) on the Y axis to create a graph such as that shown in Figure 5. This graph is processed using the least squares method to calculate the slope and intercept of the linear function. The calculated slope and intercept are input into the equation κ = a(T3 - T2 ± 3) + b, where a is the slope and b is the intercept, and the equation (2) of the present invention is obtained: κ = -(1.8 x 10 -3 )×(T3-T2±3)+(5.7×10 －2 ) was obtained. Furthermore, since T1-T2 was within ±3°C, the formula (1): κ = -(1.8 × 10 -3 )×(T3-T1±3)+(5.7×10 －2 ) also holds.

[0097] 2. Example 1 2-1. Temperature Measurement Process A resistance temperature detector was installed on the outer surface of the sheet heater, which was a laminate formed by laminating the first insulating layer, the heat-generating layer, and the second insulating layer in this order. A platinum sensor with a measurement range of -200 to 660°C was used as the resistance temperature detector. The sheet heater and the resistance temperature detector were attached using double-sided tape (Kapton (registered trademark) 760H, manufactured by Teraoka Seisakusho Co., Ltd.)) to form a heater with a resistance temperature detector without a low thermal conductor. A temperature controller was attached to the resistance temperature detector. The heater with a resistance temperature detector without a low thermal conductor was then attached to the outer surface of the installation body. The first insulating layer of the sheet heater was attached to the surface of the installation body. The installation body was a cylindrical pipe 1 with a diameter of 27.2 mm, a length of 300 mm, a wall thickness of 2.8 mm, and made of stainless steel. Next, electricity was applied to the heating layer of the sheet-type heater, and the temperature of the resistance temperature detector was adjusted to 120°C. A thermocouple was then installed on the outer surface of the second insulating layer, and the outer surface temperature (T3) of the sheet-type heater was measured. A thermocouple was also installed on the outer surface of the cylindrical pipe 1, and the outer surface temperature (T2) of that thermocouple was measured. After the adjusted temperature stabilized, the temperature difference (T3 - T2) was calculated, and was found to be 3°C.

[0098] 2-2. Adjustment process Next, the thermal conductivity when T3 - T2 was 3°C was confirmed using the graph in Figure 5, and it was found that, among the low thermal conductors made of PTFE fiber sheets with various thermal conductivities obtained above, it was optimal to select a low thermal conductor made of a single PTFE fiber sheet.

[0099] 2-3. Installation Process Next, a resistance temperature detector was installed on the outer surface of the second insulating layer of the same sheet-type heater used in the temperature measurement process, via a low thermal conductor consisting of a single PTFE fiber sheet, to obtain a heater with a resistance temperature detector 1. Here, a platinum sensor with a measurement range of -200 to 660°C was used as the resistance temperature detector. In addition, the sheet-type heater consisting of a single low thermal conductor and the resistance temperature detector were attached using double-sided tape (Kapton (registered trademark) 760H, (manufactured by Teraoka Seisakusho)). A temperature controller was attached to the resistance temperature detector. Next, the above-mentioned heater with a resistance temperature detector 1 was attached to the outer surface of the cylindrical pipe 1, to obtain a heater-equipped installation body 1. Here, the first insulating layer of the sheet-type heater was attached to the surface of the cylindrical pipe 1.

[0100] 2-4. Evaluation Electricity was applied to the heat generating layer of the heater-equipped application body 1 obtained, and the temperature of the resistance thermometer was adjusted to 120°C. After the adjusted temperature stabilized, the difference (T1-T2) between the temperature indicated by the resistance thermometer (T1) and the outer surface temperature of the application body (T2) was confirmed to be 0.7°C.

[0101] 3. Example 2 3-1. Temperature Measurement Process A resistance temperature detector was installed on the outer surface of the sheet-type heater used in Example 1. A platinum sensor with a measurement range of -200 to 660°C was used as the resistance temperature detector. The sheet-type heater was attached to the resistance temperature detector using double-sided tape (Kapton (registered trademark) 760H, manufactured by Teraoka Seisakusho Co., Ltd.)) to create a heater with a resistance temperature detector without a low thermal conductor. A temperature regulator was attached to the resistance temperature detector. Next, the heater with a resistance temperature detector without a low thermal conductor was attached to the outer surface of the heater body. Here, the first insulating layer of the sheet-type heater was attached to the surface of the heater body. The heater body was a cylindrical pipe 2 with a diameter of 42.7 mm, a length of 300 mm, a wall thickness of 3.5 mm, and made of stainless steel. Next, electricity was applied to the heating layer of the sheet-type heater, and the resistance temperature detector was adjusted to a temperature of 120°C. A thermocouple was installed on the outer surface of the second insulating layer to measure the outer surface temperature (T3) of the sheet heater. A thermocouple was also installed on the outer surface of the cylindrical pipe 2 to measure its outer surface temperature (T2). After the adjusted temperature stabilized, the temperature difference (T3 - T2) was calculated and found to be 17°C.

[0102] 5, the thermal conductivity when T3-T2 was 17°C was confirmed. It was found that, among the low thermal conductors made of PTFE fiber sheets with various thermal conductivities obtained above, a low thermal conductor made of three PTFE fiber sheets was optimal. The three-layer low thermal conductor was one in which the PTFE fiber sheets were attached to each other with double-sided tape (Kapton (registered trademark) 760H, manufactured by Teraoka Seisakusho Co., Ltd.).

[0103] 3-3. Installation Process Next, a resistance temperature detector was installed on the outer surface of the second insulating layer of the same sheet heater used in the temperature measurement process, via a low thermal conductor consisting of three PTFE fiber sheets, to obtain a heater with a resistance temperature detector 2. Here, the same platinum sensor as in Example 1 was used as the resistance temperature detector. The three-layer low thermal conductor sheet heater and the resistance temperature detector were attached using double-sided tape (Kapton (registered trademark) 760H, manufactured by Teraoka Seisakusho Co., Ltd.). A temperature controller was attached to the resistance temperature detector. Next, the above-mentioned heater with a resistance temperature detector 2 was attached to the outer surface of the cylindrical pipe 2, to obtain a heater-equipped installation body 2. Here, the first insulating layer of the sheet heater was attached to the surface of the cylindrical pipe 2.

[0104] 3-4. Evaluation Electricity was applied to the heat generating layer of the heater-equipped application body 2 obtained, and the temperature of the resistance thermometer was adjusted to 120°C. After the adjusted temperature stabilized, the difference (T1-T2) between the temperature indicated by the resistance thermometer (T1) and the outer surface temperature of the application body (T2) was confirmed to be 2.5°C.

[0105] 4. Example 3 4-1. Temperature Measurement Step A resistance temperature detector was installed on the outer surface of the sheet heater used in Example 1. A platinum sensor with a measurement range of -200 to 660°C was used as the resistance temperature detector. The sheet heater was attached to the resistance temperature detector using double-sided tape (Kapton (registered trademark) 760H, manufactured by Teraoka Seisakusho Co., Ltd.) to create a heater with a resistance temperature detector without a low thermal conductor. A temperature regulator was attached to the resistance temperature detector. Next, an aluminum plate serving as an installation jig with a cross-sectional thickness of 1 mm, a cross-sectional width of 30 mm, and a depth of 100 mm was attached to the outer surface of the first insulating layer of the heater with a resistance temperature detector without a low thermal conductor using double-sided tape (Kapton (registered trademark) 760H, manufactured by Teraoka Seisakusho Co., Ltd.), and then attached to the outer surface of the installation body as shown in Figure 2. Here, the outer surface of the first insulating layer of the sheet heater was attached to a portion of the installation body. The installation object used was a square pipe 1 having a length of 40 mm, a depth of 100 mm, and made of aluminum, as shown in Figure 2A. Next, electricity was applied to the heating layer of the sheet heater, and the resistance temperature detector was adjusted to a temperature of 120°C. A thermocouple was then installed on the outer surface of the second insulating layer, and the outer surface temperature (T3) of the heating layer was measured. A thermocouple was also installed on the outer surface of the square pipe 1 that contacted the aluminum plate, and the outer surface temperature (T2) was measured. After the adjusted temperature stabilized, the temperature difference (T3 - T2) was calculated, and was found to be 10°C.

[0106] 5, the thermal conductivity when T3-T2 was 10°C was confirmed. It was found that, among the low thermal conductors made of PTFE fiber sheets with various thermal conductivities obtained above, a low thermal conductor made of two PTFE fiber sheets was optimal. The two-sheet low thermal conductor was one in which the PTFE fiber sheets were attached with double-sided tape (Kapton (registered trademark) 760H, manufactured by Teraoka Seisakusho Co., Ltd.)).

[0107] 4-3. Installation Process Next, a resistance temperature detector was installed on the outer surface of the second insulating layer of the same sheet heater used in the temperature measurement process, via a low thermal conductor consisting of two PTFE fiber sheets, to obtain a heater with a resistance temperature detector 3. Here, the same platinum sensor as in Example 1 was used as the resistance temperature detector. The two-layer low thermal conductor sheet heater and the resistance temperature detector were attached using double-sided tape (Kapton (registered trademark) 760H, manufactured by Teraoka Seisakusho Co., Ltd.). A temperature controller was attached to the resistance temperature detector. Next, an aluminum plate, the same installation jig as used in the temperature measurement process, was attached to the outer surface of the first insulating layer of the sheet heater of the resistance temperature detector-equipped heater 3 using double-sided tape (Kapton (registered trademark) 760H, manufactured by Teraoka Seisakusho Co., Ltd.), and then attached to the outer surface of the square pipe 1 as shown in FIG. 2 to obtain a heater-equipped installation body 3. Here, the first insulating layer of the sheet heater was attached to a part of the square pipe 1 and the surface of the aluminum plate.

[0108] 4-4. Evaluation Electricity was applied to the heating layer of the obtained heater-equipped construction body 3, and the temperature of the resistance thermometer was adjusted to 120°C. After the adjusted temperature stabilized, the difference (T1-T2) between the temperature (T1) indicated by the resistance thermometer and the outer surface temperature (T2) of the square pipe 1 was confirmed to be 1.8°C.

[0109] From the above, it is possible to provide a heater with a resistance thermometer that has a low thermal conductor between the resistance thermometer and the sheet-type heater and is installed on the outer surface of an installation body such as a pipe, and then by passing electricity through it, when the resistance thermometer is set to the desired temperature, the temperature of the outer surface of the installation body can also be set to a temperature close to the desired temperature, as well as a heater-equipped installation body including the same and a heater installation method.

[0110] This application claims priority based on Japanese Patent Application No. 2024-54494, filed March 28, 2024, the disclosure of which is incorporated herein in its entirety by reference.

[0111] REFERENCE SIGNS LIST 1, 1' Attached body 2, 2' Sheet heater 3, 3' Low thermal conductor 4, 4' Resistance temperature detector 5, 5' Heater of the present invention 7 Member with high thermal conductivity 10, 10' Attached body with heater of the present invention 20 Attached body 22 Sheet heater 21 Attached body 23 Sheet heater 25 Low thermal conductor 27 Resistance temperature detector 30 Attached body with heater of the present invention

Claims

1. A heater with a resistance thermometer sensor, comprising a sheet heater and a resistance thermometer sensor, and further comprising a low thermal conductor between the sheet heater and the resistance thermometer sensor, wherein the low thermal conductor has a thermal conductivity such that the difference (T1-T2) between the temperature (T1) indicated by the resistance thermometer sensor during use and the outer surface temperature (T2) of the applied body is within ±3°C.

2. The heater with a resistance temperature detector according to claim 1, wherein the relationship between the difference (T3 - T1) between the outer surface temperature (T3) of the sheet heater during use and the temperature (T1) indicated by the resistance temperature detector, and the thermal conductivity (κ) of the low thermal conductor, satisfies the following formula (1): κ = -(1.8 x 10 -3 )×(T3-T1±3)+(5.7×10 －2 ) 3. The heater with a resistance temperature sensor according to claim 1 or 2, wherein the relationship between the difference (T3 - T2) between the outer surface temperature (T3) of the sheet heater and the outer surface temperature (T2) of the applied body during use and the thermal conductivity (κ) of the low thermal conductor satisfies the following formula (2): κ = -(1.8 x 10 -3 )×(T3-T2±3)+(5.7×10 －2 ) 4. A heater with a resistance temperature sensor according to any one of claims 1 to 3, wherein the thermal conductivity of the low thermal conductor at room temperature is 0.01 to 0.06 W / m·K.

5. A heater with a resistance temperature detector as described in any one of claims 2 to 4, wherein the difference (T3 - T1) between the outer surface temperature (T3) of the sheet-type heater during use and the temperature (T1) indicated by the resistance temperature detector is 2.5 to 20°C.

6. A heater with a resistance temperature sensor as described in any one of claims 3 to 5, wherein the difference (T3 - T2) between the outer surface temperature (T3) of the sheet heater and the temperature (T2) of the applied object during use is 2.5 to 20°C.

7. A heated construction body having a heater with a resistance temperature detector installed on the outer surface of the construction body, wherein the heater with a resistance temperature detector has a sheet-type heater, a low thermal conductor, and a resistance temperature detector, and the heater with a resistance temperature detector is installed on the outer surface of the construction body so that the sheet-type heater is on the side closer to the construction body and the resistance temperature detector is on the side farther from the construction body, and the low thermal conductor is between them, and the low thermal conductor has a thermal conductivity such that the difference (T1 - T2) between the temperature (T1) indicated by the resistance temperature detector during use and the outer surface temperature (T2) of the construction body is within ±3°C.

8. The heated structure according to claim 7, wherein the relationship between the difference (T3-T1) between the outer surface temperature (T3) of the sheet heater during use and the temperature (T1) indicated by the resistance temperature detector, and the thermal conductivity (κ) of the low thermal conductor, satisfies the following formula (1): κ=-(1.8×10 -3 )×(T3-T1±3)+(5.7×10 －2 ) 9. The heater-equipped body according to claim 7 or 8, wherein the relationship between the difference (T3 - T2) between the outer surface temperature (T3) of the sheet heater and the outer surface temperature (T2) of the body during use and the thermal conductivity (κ) of the low thermal conductor satisfies the following formula (2): κ = -(1.8 x 10 -3 )×(T3-T2±3)+(5.7×10 －2 ) 10. A heater-equipped object according to claim 9, wherein the difference (T3-T2) between the outer surface temperature (T3) of the sheet heater and the outer surface temperature (T2) of the object during use is 2.5 to 20°C.

11. A heater installation method for installing a heater with a resistance temperature detector, which comprises a sheet heater, a low thermal conductor, and a resistance temperature detector, on the outer surface of an installation body, comprising: a temperature measurement step of installing the sheet heater on the outer surface of the installation body, adjusting the sheet heater to the temperature during use, and then measuring the outer surface temperature (T3) of the sheet heater and the outer surface temperature (T2) of the installation body; and an adjustment step of selecting the low thermal conductor having a thermal conductivity such that the difference (T1 - T2) between the temperature (T1) indicated by the resistance temperature detector and the outer surface temperature (T2) of the installation body is within ±3°C, using a previously determined relational expression for the difference (T3 - T2) between the outer surface temperature (T3) of the sheet heater and the outer surface temperature (T2) of the installation body, and the thermal conductivity (κ) of the low thermal conductor. a construction step of installing the heater with resistance temperature detector on the outer surface of the workpiece so that the sheet heater is on the side closer to the workpiece, the resistance temperature detector is on the side farther away, and the low thermal conductor selected in the adjustment step is located between them.

12. The heater installation method according to claim 11, wherein the relationship between the difference (T3-T2) between the outer surface temperature (T3) of the sheet heater and the outer surface temperature (T2) of the applied body, which is determined in advance in the adjusting step, and the thermal conductivity (κ) of the low thermal conductor is expressed by the following formula (2): Formula (2): κ=-(1.8×10 -3 )×(T3-T2±3)+(5.7×10 －2 ) 13. The heater installation method according to claim 11 or 12, wherein the relationship between the difference (T3 - T1) between the outer surface temperature (T3) of the sheet-type heater and the temperature (T1) indicated by the resistance temperature detector when the heater with resistance temperature detector is in use, and the thermal conductivity (κ) of the low thermal conductor satisfies the following formula (1): Formula (1): κ = -(1.8 x 10 -3 )×(T3-T1±3)+(5.7×10 －2 ) 14. A heater installation method according to any one of claims 11 to 13, wherein the object to be installed is a pipe.

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