JP6570201B2 - Micro heater with non-heat generating part - Google Patents

Description

  The present invention relates to a microheater having a non-heat generating portion among microheaters in which an inorganic insulating material powder is interposed in a metal sheath tube and a heating wire generating Joule heat by energization is accommodated.

  The micro-heater is a flexible heater in which an inorganic insulating material powder is interposed in a metal sheath tube and accommodates a heating wire that generates Joule heat when energized. The basic structure is shown in FIGS. 6 and 7. There are two types. FIG. 6 is a cross-sectional view showing a basic first general configuration of a conventional microheater, and FIG. 7 is a cross-sectional view showing a basic second configuration of the conventional microheater.

  6 (a) and 7 (a) are longitudinal sectional views, and FIG. 6 (b) and FIG. 7 (b) are EE cross-sections in FIG. 6 (a) and FIG. 7 (a), respectively. It is a figure of the FF cross section. However, the terminal sleeve 9 and the insulation coatings 13 and 15 of the lead wires 80 and 81 for supplying electricity are drawn in an outer shape, and FIG. 6 (b) and FIG. 7 (b) are shown in FIG. a), drawn at a larger scale than FIG.

  In the microheater 10 shown in FIG. 6, the heating wire 6 is accommodated in the metal sheath tube 5 with the inorganic insulating material powder 12 interposed therebetween, and terminal sleeves 9 are provided at both ends thereof. The conductors 14 and 16 exposed from the insulating coatings 13 and 15 of the lead wires 80 and 81 are connected to the terminal. In the metal outer frame of the terminal sleeve 9, the end of the heating wire 6 and the tips of the conductors 14 and 16 are connected so that moisture does not enter the inorganic insulating powder 12 and the insulation resistance does not decrease. A seal is provided.

  The microheater 20 shown in FIG. 7 differs from the microheater 10 shown in FIG. 6 in that the reciprocating heating wire 6 is accommodated in the metal sheath tube 5 with the inorganic insulating material powder 12 interposed therebetween. Is provided only on one side. The role of the terminal sleeve 9 is the same as that of the terminal sleeve 9 of FIG. 6, and the end of the heating wire 6 and the tips of the conductors 14 and 16 exposed from the insulating coatings 13 and 15 of the lead wires 80 and 81 in the metal outer frame. In addition, a seal is provided to prevent moisture from entering the inorganic insulating material powder 12 and lowering the insulation resistance.

  As a material of the heating wire 6 of the microheaters 10 and 20 in FIGS. 6 and 7, nichrome having a high resistivity and a large amount of heat generation is used except for special exceptions. Further, the specific structure inside the terminal sleeve 9 is typically the one shown in FIG. As shown in the figure, the end of the heating wire (reference numeral 22) and the conductor of the lead wire (reference numeral 13) in the metal outer frame (reference numeral 11) interpose an insulating material (reference numerals 14 and 17). The outer frame (reference numeral 11) is housed, and a seal (reference numeral 15) is provided at the end of the metal outer frame (reference numeral 11). In addition, in each terminal sleeve 9 in the structure of FIG. 6, the heating wire (reference numeral 22) and the conductor (reference numeral 13) of FIG. Here, the reference numerals in parentheses are those shown in FIG.

  When the object to be heated and the terminal seal are separated, for example, when the object to be heated is in the container, the terminal sleeve 9 in FIGS. 6 and 7 is usually placed outside the container, and the heating wire 6 and the inorganic insulating material powder A metal sheath tube 5 containing 12 is laid to the object to be heated in the container. In this case, in the microheaters 10 and 20 of FIG. 6 and FIG. 7 in which the heating wire 6 extends over the entire length in the metal sheath tube 5, the portions that do not need to be heated are also heated, and the microheaters 10 and 20 are unnecessary. Inconveniences such as damage to the equipment due to excessive power consumption and heating of the equipment in the container having a low heat-resistant temperature other than the object to be heated occur.

  In order to avoid such an adverse effect when the object to be heated and the terminal seal are separated from each other, conventionally, only the part that is heated in contact with the object to be heated generates heat and the other part does not generate heat. In many cases, micro heaters 11 and 21 shown in FIG. FIG. 8 is a cross-sectional view showing a basic first configuration of a conventional microheater having a non-heat generating portion, and FIG. 9 is a cross-sectional view showing a basic second configuration of a conventional micro-heater having a non-heat generating portion. 8 and 9 show the outer shapes of the insulation coatings 13 and 15 of the terminal sleeve 9 and the lead wires 80 and 81 as in FIGS. 6 and 7.

  6 and 7, the heating wire 6 made of nichrome having a high electrical resistivity generates heat over the entire length, whereas the microheaters 11 and 21 in FIGS. A heat generating part in which a heating wire 6 made of nichrome wire is housed, a non-heating part in which a non-heating wire 7 made of copper having a small heat generation due to its low electrical resistivity is housed, and an alloy of nichrome and copper It can be divided into an intermediate heating part where the part 19 exists. Except for the presence of the non-heat generating wire 7 and the alloy part 19, the same structure as that of the microheaters 10 and 20 in FIGS. 6 and 7 is used, and the same components are shown in FIGS. .

  In the microheaters 11 and 21 of FIGS. 8 and 9, by using only the portion that contacts and heats the object to be heated as a heat generating portion, wasteful power consumption is suppressed, and damage to the equipment due to unnecessary heating is avoided. be able to.

  6 to 9, the portion containing the metal wire such as the heating wire 6 and the non-heating wire 7 with the inorganic insulating material powder 12 interposed in the metal sheath tube 5 is often referred to as a micro heater cable. Hereinafter, the micro heater cable refers to this portion. As shown in FIGS. 7 and 8 of Patent Document 2, the microheater cable is first made thicker than the finished diameter, and this is reduced in diameter by die drawing or swaging, and the predetermined value shown in FIG. Finished in diameter micro heater cable.

  In the microheater having the non-heat generating portion shown in FIGS. 8 and 9, the metal wire accommodated when making the micro cable thicker than the finished diameter before the diameter reduction is formed at both ends of the heating wire 6 thicker than the finished diameter made of nichrome. A non-heating wire 7 made of copper having substantially the same diameter is butt welded.

  In the butt welding of the heating wire 6 and the non-heating wire 7, an alloy part of nichrome, which is the material of the heating wire 6, and copper, which is the material of the non-heating wire 7, inevitably occurs, and this alloy part is expanded after being reduced in diameter. The alloy part 19 becomes an intermediate heat generating part having an intermediate resistance between nichrome and copper.

  Note that the generation of Joule heat is not zero even with copper wires. Since the calorific value per unit length is proportional to the square of the applied current and the resistance value per unit length, the calorific value per unit length of two connected lines through which the same current flows is per unit length. It is proportional to the resistance value. If the two types of wires have the same diameter, the resistance value per unit length is proportional to the electrical resistivity, so the amount of heat generated per unit length is proportional to the electrical resistivity. 8 and 9, the electrical resistivity of copper is about 1.6% of that of nichrome. Therefore, the heat generation amount per unit length is about 1 of the heat generation amount per unit length of the heat generation portion. It is 6%. As described above, the non-heat generating line and the non-heat generating part generate heat although they are small compared to the heat generating line and the heat generating part. In the following, lines and portions that generate less heat than heat generation lines and heat generation parts are referred to as non-heat generation lines and non-heat generation parts, respectively.

JP 2010-257582 A JP 2017-1112079 A

  As is well known, it is difficult to weld dissimilar metals. As described above, in the conventional microheater having the non-heating portion shown in FIGS. 8 and 9, butt welding before the diameter reduction of the heating wire 6 made of nichrome and the non-heating wire 7 made of copper is necessary. is there.

  In this butt weld, a bulge of the alloy part 19 and a dent 22 of the non-heating wire 7 as shown in FIG. The reason for this is that the melting point of copper is lower than that of nichrome and the thermal conductivity of copper is high. Therefore, during butt welding, the copper melts extensively before being heated to the melting point of nichrome, and the copper melted by the surface tension. Still moves to the solid nichrome side, and after welding, the shape shown in FIG. 10 (a), that is, the non-heating wire 7 side of the alloy portion 19 swells around the entire circumference, It is considered that a dent 23 is formed on the entire circumference near the boundary, and when this is reduced to the finished diameter, the bulge of the alloy part 19 and the dent 22 of the non-heating line 7 in FIG.

  Since the thermal expansion coefficients of the nichrome heating wire 6 and the copper non-heating wire 7 are different from those of the inorganic insulating material powder 12 and the metal sheath tube 5, the heating wire 6 and the non-heating wire 7 are used when the micro heater is used. Tensile and compressive stresses are generated. This stress is particularly great when the temperature rises and falls when the temperature difference from the metal sheath tube 5 increases. When the temperature rises and falls repeatedly, the stress is broken at the portion where the diameter is reduced by the recess 22 of the copper non-heating wire 7. The conventional microheater having a non-heated part has a problem that may occur. If the temperature of the welded part is not sufficiently raised to eliminate the dent, the conduction between the heating wire 6 and the non-heating wire 7 becomes insufficient, and the temperature of this part rises excessively during use due to the presence of contact resistance. As a result, another problem of disconnection due to evaporation of the heating lines 6 and the non-heating lines 7 occurs.

  As a countermeasure for the problem that the diameter may be reduced by the recess 22 of the non-heating wire 7 and disconnection may occur during use, an alloy wire mainly composed of nickel having an intermediate thermal conductivity or melting point between copper and nichrome, In some cases, an alloy wire containing copper as a main component or a wire in which nickel is clad on copper is used as a relay wire between a heating wire and a non-heating wire. In this case, since a short relay wire is butt welded to a heating wire made of nichrome, and a copper non-heating wire is butt welded to the relay wire, the dent of the non-heating wire is reduced. However, the dent does not disappear at all, and the disconnection problem cannot be completely solved. Also, in this method, the electrical resistance of the relay wire is usually an intermediate value between nichrome and copper, so the relay wire becomes the intermediate heat generating portion shown in FIGS. 8 and 9, and the intermediate heat generating portion becomes longer. Problems arise. If the intermediate heat generating portion becomes longer, useless power consumption in this portion increases, and the adverse effect of increasing the possibility that a portion that should not be heated increases.

  The present invention has been made in view of the disconnection problem caused by the dent of the non-heat generation line caused by the welding of different metals in the conventional microheater having the non-heat generation section. It aims at providing a certain micro heater.

(First aspect)
A microheater having a non-heat generating portion according to the present invention,
A metal sheath tube with no change in outer diameter in the axial direction ;
A heating wire that is housed in a metal sheath tube and generates Joule heat when energized using Nichrome,
It is housed in a metal sheath tube, made of copper and made of non-heat generating wire having the same diameter as the heating wire,
A connecting tube that is housed in a metal sheath tube, made of metal and having an inner diameter that is substantially the same as the heating wire and the non-heating wire,
An inorganic insulating material powder filled between a metal sheath tube and a heating wire, a non-heating wire, and a connecting tube,
One end of the heating wire and one end of the non-heating wire are in contact with each other in the connecting pipe, and only the end of the heating wire that contacts the non-heating wire and the end of the non-heating wire that contacts at least the heating wire Is inside the connecting pipe, the inner surface of the connecting pipe is in contact with the inner heating wire and the outer surface of the non-heating wire, and the part where the non-heating wire exists is outside the connecting tube of the heating wire It is a non-heat generating part with a smaller heat generation amount.

  As described above, in the manufacture of the microheater cable, a thicker one than the finished diameter is first made, and the diameter is reduced by die drawing or swaging to finish the microheater cable having a predetermined diameter. A microheater without a non-heat generating part makes a long micro heater cable by reducing the diameter reduction ratio and cuts this to produce a large number of micro heaters, whereas a micro heater with a non-heat generating part Then, because the position of the heat generating part varies depending on the place to be used, and since there are heat generating part and non-heat generating part, it is not possible to cut a long micro heater cable and produce a large number of micro heaters, Usually, the diameter reduction rate is about one-half to one-third.

  Although the diameter reduction ratio in the manufacture of the microheater cable having the non-heat generating portion according to the present invention is about one half to one third, the heating wire, the non-heating wire and the connecting pipe before the diameter reduction are connected to the heating wire. A state where one end and one end of a non-heating wire having substantially the same diameter as the heating wire are in contact with each other, and an end portion of the heating wire contacting the non-heating wire in a connecting tube having an inner diameter where the heating wire and the non-heating wire can be barely inserted; And at least the end of the non-heat-generating wire in contact with the heat generating wire is temporarily fixed and welded so that the connecting tube is squeezed by the external force at the time of diameter reduction after the diameter is reduced. In a state where one end of the heating wire and one end of the non-heating wire are in contact with each other, there is an end portion in contact with the non-heating wire of the heating wire and at least an end portion in contact with the heating wire of the non-heating wire in the connecting pipe In addition, between the inner surface of the connecting pipe and the outer surface of the heating wire and non-heating wire, It is also fixed in tight contact with reduced diameter as were gaps.

  Preheated heating wire, non-heating wire and connecting tube can be temporarily welded, so spot welding can be used, and no conventional temperature increase is required until the entire cross-section is completely melted. Therefore, unlike the conventional microheater having a non-heat generating portion, the non-heat generating wire is not depressed, and the heat generating wire and the connecting tube are not depressed. Therefore, there is no fear that disconnection due to the dent of the non-heat generation line like the micro heater with the conventional non-heat generation portion will occur.

  In addition, even if the contact between the heating wire and the non-heating wire is insufficient and the contact resistance remains, the inner surface of the connecting tube is in close contact with the surface of the heating wire and the non-heating wire in the tube. Will not flow excessively during use.

  As described above, the heat generation amount per unit length is proportional to the resistance value per unit length. The resistance value of the part where there is a non-heating wire in the connecting pipe is the resistance value in which the resistance of the non-heating line and the connecting pipe are connected in parallel, so the resistance value per unit length is the resistance value of the non-heating line outside the connecting pipe. Less than the resistance value per unit length. This indicates that the portion having the non-heat generation line in the connecting pipe belongs to the non-heat generation portion, and the heat generation amount per unit length is smaller than that of the non-heating line outside the connection pipe.

  On the other hand, the resistance value of the portion where the heating wire is in the connecting pipe is a resistance value in which the resistance of the heating wire and the connecting pipe are connected in parallel. Therefore, the resistance value per unit length is the resistance value of the heating wire outside the connecting pipe. It is smaller than the resistance value per unit length and is usually larger than the resistance value per unit length of the non-heating wire outside the connecting pipe. Therefore, the amount of heat generated per unit length of the part where the heating wire is inside the connecting pipe is an intermediate amount between the heating line outside the connecting pipe and the non-heating line, and the part where the heating line is inside the connecting pipe becomes the intermediate heating part. Become.

  The intermediate heat generating part has a detrimental effect that wasteful power is consumed and a possibility that a portion that should not be heated is heated increases. However, in the microheater having the non-heat generating part of the present invention, heat is generated in the connecting pipe. By shortening the insertion length of the wire, the intermediate heat generating portion can be shortened, and by doing so, the adverse effects of the intermediate heat generating portion can be reduced.

(Second aspect)
In the microheater having a non-heat generating portion of the present invention, the non-heat generating wire in the connecting pipe may be only the end portion that contacts the heat generating wire of the non-heat generating wire. In this case, there is no fear of disconnection due to the dent of the non-heat generation line, and the effect in the first aspect in which an excessive temperature rise due to contact resistance does not occur is inherited as it is.

(Third aspect)
Furthermore, the non-heating line in the connecting pipe may be the entire length of the non-heating line. In this case as well, there is no fear of disconnection due to the depression of the non-heat generation line, and no excessive temperature rise due to contact resistance occurs. In addition, since the entire length of the non-heating line is in the connecting pipe, the heat generation amount per unit length of the non-heating part is smaller than that of the non-heating line not covered by the connecting pipe, as described above. Accordingly, useless heat generation and power consumption are eliminated.

(Fourth aspect)
The material of the connecting pipe is preferably nickel or copper. Nickel capillaries and copper capillaries are commercially available and easy to obtain, and it is economically advantageous to use nickel or copper as the material of the connecting tube.
When copper is used as the material of the connecting pipe, the electrical resistivity of copper is low. Therefore, there is a small amount of heat generated in the connecting pipe that becomes the intermediate heat generating part, and there is a non-heating line in the connecting pipe that becomes the non-heating part. The amount of heat generated is small. Therefore, the effect of reducing wasteful heat generation and power consumption is great.
In addition, the electrical resistivity of nickel is higher than copper but low as close to copper. By using nickel as the material of the connecting tube, the effect of suppressing wasteful heat generation and power consumption, even if not as high as copper, is great. .

  As described above, the microheater having a non-heat generating portion according to the present invention can eliminate the decrease in diameter due to the dent near the welded portion with the heat generating wire, which has conventionally occurred in the non-heat generating wire, and occurs during use. There is no fear of disconnection due to stress. In addition, even if the contact between the heating wire and the non-heating wire is inadequate and contact resistance remains, the current also flows through the connecting pipe, so that there is no undue temperature rise during use. There is also.

Sectional drawing which shows 1st Embodiment of the micro heater with a non-heat-generating part by this invention Sectional drawing which shows 2nd Embodiment of the microheater with a non-heating part by this invention Sectional drawing which shows 3rd Embodiment of the microheater with a non-heating part by this invention Sectional drawing which shows 4th Embodiment of the micro heater with a non-heat-generating part by this invention Sectional drawing which shows the boundary part of the exothermic line and non-exothermic line in 1st Embodiment of this invention Sectional drawing which shows the basic 1st structure of the conventional microheater Sectional drawing which shows the 2nd basic structure of the conventional microheater Sectional drawing which shows the 1st basic composition of the micro heater with the conventional non-heating part Sectional drawing which shows the 2nd basic structure of the conventional microheater with a non-heat-generating part Sectional drawing which shows the boundary part of the exothermic line and non-exothermic line in the basic 1st structure of the conventional microheater with a non-exothermic part

  First to fourth embodiments for carrying out the present invention will be described.

(First embodiment)
FIG. 1 is a sectional view showing a first embodiment of a microheater having a non-heat generating portion according to the present invention, FIG. 1 (a) is a longitudinal sectional view, and FIGS. 1 (b) and 1 (c) are respectively diagrams. It is the AA cross section of 1 (a), and a BB cross section. However, the terminal sleeve 9 and the insulation coatings 13 and 15 of the lead wires 80 and 81 in FIG. 1A are drawn in outlines, and FIG. 1B and FIG. It is drawn at a large scale. In addition, the reference numerals in the drawings are the same as those in FIGS. 6 to 9 for components having the same functions as those of the conventional microheater shown in FIGS. 6 to 9, and this is also shown in FIG. It is the same.

  In the microheater 1 having a non-heat generating portion of the first embodiment, an inorganic insulating material powder 12 is interposed in a metal sheath tube 5 and a heating wire 6 that generates Joule heat by energization using nichrome, and copper is used. A non-heating wire 7 made of the same material and the same diameter as the heating wire 6 and a heating wire 6 made of nickel and the inner diameter of the heating wire 6 and a connecting tube 8 having the same diameter as the non-heating wire 7 are accommodated. One end and one end of the non-heat generating wire 7 are in contact with each other, and the end portion of the heat generating wire 6 that contacts the non-heat generating wire 7 and the end portion of the non-heat generating wire 7 that contacts the heat generating wire 6 are connected in the connecting tube 8. The inner surface of the connecting tube 8 is in contact with the outer surfaces of the heating wire 6 and the non-heating wire 7 inside.

  Terminal sleeves 9 are provided at both ends of the metal sheath tube 5, the inorganic insulating material powder 12, and the metal sheath tube 5 other than the connecting tube 8, and lead wires 80 and 81 for energizing the terminal sleeve 9. The structure in which the conductors 14 and 16 exposed from the insulating coatings 13 and 15 are connected is the same as that of the microheater 11 having the conventional non-heat generating portion shown in FIG. In addition, the structure in the terminal sleeve 9 made the heating wire shown with the code | symbol 22 in FIG. 1 of the patent document 1 and the conductor shown with the code | symbol 13 by the same applicant as this patent application one each. Structure.

  In this embodiment as well as in the prior art, in the production of the part called microheater cable in which the heating wire 6, the non-heating wire 7 and the connecting tube 8 are accommodated with the inorganic insulating material powder 12 interposed in the metal sheath tube 5, As shown in the figure, a thicker one than the finished diameter is first made, and the diameter is reduced to one-half to one-third by die drawing or swaging to finish a micro heater cable having a predetermined outer diameter.

  The heating wire 6, the non-heating wire 7 and the connecting tube 8 before the diameter reduction can be inserted with the heating wire 6 and the non-heating wire 7 barely in contact with one end of the heating wire 6 and one end of the non-heating wire 7. In the connecting pipe 8 having the inner diameter, the end of the heating wire 6 that contacts the non-heating wire 7 and the end of the non-heating wire 7 that contacts the heating wire 6 are temporarily fixed and welded. After the diameter reduction, the shape shown in FIG. 1 is obtained.

  Since the heating wire 6, the non-heating wire 7 and the connecting tube 8 before the diameter reduction may be temporarily fixed, spot welding can be used, and there is no need to raise the temperature until the entire cross-section is completely melted. For this reason, there is no dent in the non-heat generation line unlike the conventional microheater having the non-heat generation part, and no dent is generated in the heat generation line 6 and the connecting pipe 8. Therefore, there is no fear that disconnection due to the dent of the non-heat generation line like the micro heater with the conventional non-heat generation portion will occur.

  Further, even if there is a slight gap between the inner surface of the connecting tube 8 and the heating wire 6 and the non-heating wire 7 and the outer surface before the diameter reduction, they are in close contact with each other due to the diameter reduction. Therefore, even if the contact between the heating wire 6 and the non-heating wire 7 is insufficient and the contact resistance remains, the inner surface of the connecting tube 8 is in close contact with the surfaces of the heating wire 6 and the non-heating wire 7 in the tube. The current also flows through the connecting tube 8 and has an attendant advantage that an excessive temperature rise due to contact resistance during use does not occur.

  The amount of heat generated per unit length is proportional to the resistance value per unit length. Since the resistance value of the portion where the non-heating wire 7 is present in the connecting pipe 8 is a resistance value in which the resistance of the non-heating wire 7 and the connecting pipe 8 is connected in parallel, the resistance value per unit length is the connecting pipe 8. It is smaller than the resistance value per unit length of the outer non-heating line 7. This indicates that the portion where the non-heat generating wire 7 is present in the connecting pipe 8 belongs to the non-heat generating portion, and the heat generation amount per unit length is smaller than that of the non-heating wire 7 outside the connecting tube 8. . Accordingly, all portions where the non-heat generating line 7 is present become non-heat generating portions.

  On the other hand, the resistance value of the portion where the heating wire 6 is in the connecting tube 8 is a resistance value in which the resistance of the nichrome heating wire 6 and the nickel connecting tube 8 are connected in parallel. Is smaller than the resistance value per unit length of the nichrome heating wire 6 outside the connecting tube 8, and is usually larger than the resistance value per unit length of the non-heating wire 7 outside the connecting tube 8. Therefore, the heat generation amount per unit length of the portion where the heating wire 6 is in the connecting pipe 8 is an intermediate amount between the heating wire 6 outside the connecting pipe 8 and the non-heating wire 7, and the heating wire in the connecting pipe 8. A portion having 6 is an intermediate heat generating portion, and a portion having the heating wire 6 outside the connecting tube 8 is a heat generating portion.

  The intermediate heat generating portion has a detrimental effect that wasteful power is consumed and the possibility that a portion that should not be heated is heated increases. However, the microheater 1 having the non-heat generating portion of the present invention is shown in FIG. Thus, by shortening the insertion length of the heating wire 6 into the connecting tube 8, the intermediate heat generating portion is shortened, thereby reducing the adverse effects of the intermediate heat generating portion and making them substantially harmless.

  Regarding the material of this embodiment, the heating wire 6, the non-heating wire 7 and the connecting tube 8 are as described above, and the heating wire 6 generates heat by using nichrome having a high electrical resistivity and a large calorific value as in the conventional case. The heat generation amount of the part is equal to that of the conventional micro heater, and the heat generation amount of the non-heat generation part 7 is made low by using copper having a low electrical resistivity to limit the wasteful power consumption. Is the same as the conventional one.

  Further, regarding the material of the connecting tube 8, a nickel thin tube and a copper thin tube are commercially available and easily available, and it is economically advantageous to use nickel or copper as the material of the connecting tube 8. In this embodiment, the material of the connecting pipe 8 is nickel. However, since the electrical resistivity of nickel is as low as that of copper, a portion where the heating wire 6 is present in the connecting pipe 8 serving as an intermediate heat generating part, a non-heat generating part. There is an advantage that the amount of heat generated in the portion where the non-heating line 7 is present in the connecting pipe 8 becomes low, and wasteful heat generation and power consumption are suppressed to a low level, though not as high as copper.

  The material of the connecting pipe 8 may be copper which is economically advantageous. Since the electrical resistivity of copper is lower than that of nickel, wasteful heat generation and power consumption are reduced as compared with the case where nickel is used as a material.

  As for other materials, the metal sheath tube 5 is SUS316, and the inorganic insulating material powder 12 is magnesia. These two materials are not limited to this, and the materials may be changed depending on the use conditions such as temperature.

  Regarding the cross-sectional shape, the outer diameter of the metal sheath tube 5 of the present embodiment is 3.2 mm, the inner diameter is 2.56 mm, the outer diameter of the heating wire 6 and the non-heating wire 7 is 0.77 mm, and the thickness of the connecting tube 8 is 0.3 mm and the outer diameter of the connecting tube 8 is 1.37 mm. The inner diameter of the metal sheath tube 5 and the outer diameters of the heating wire 6 and the non-heating wire 7 are shown in FIG. 6 and the microheater 10 with the outer diameter of the conventional metal sheath tube 5 shown in FIG. In addition, the standard inner diameter of the metal sheath tube 5 and the standard outer diameters of the heating wire 6 and the non-heating wire 7 of the microheater 11 having a non-heating portion with an outer diameter of the conventional metal sheath tube 5 of 3.2 mm It is almost the same.

  FIG. 5 is a cross-sectional view showing the boundary between the heat generating wire and the non-heat generating wire in the first embodiment of the present invention. FIG. 5 (a) is a cross section before the diameter reduction at the time of manufacturing the microheater cable, and FIG. FIG. 5C is an enlarged view of a portion surrounded by a chain line in FIG. FIG. 5 shows an example in which laser beam welding is used to temporarily fix the heating wire 6, the non-heating wire 7 and the connecting tube 8 before diameter reduction. Reference numeral 18 in the drawing denotes a temporary fixing portion by spot welding between the connecting pipe 8 and the heating wire 6. If the contact between the heating wire 6 and the non-heating wire 7 is not ensured by the method of reducing the diameter, a temporary spot welding for keeping the heating wire 6 and the non-heating wire 7 indicated by reference numeral 24 is added. When the welded portion rises from the outer diameter of the heating wire 6 and the non-heating wire 7, the raised portion is deleted by belt polishing. In FIG. 5B, the spot welds 18 and 24 are not shown because they are difficult to scale. Of course, temporary welding spot welding of the connecting pipe 8 and the non-heat generating wire 7 may also be added.

  As a modification of the connecting tube 8, the outer diameter is made substantially the same as that of the heating wire 6 and the non-heating wire 7, and the portion of the heating wire 6 and the non-heating wire 7 that enters the connecting tube 8 is narrowed as the inner diameter is reduced. May be.

(Second Embodiment)
FIG. 2 is a cross-sectional view showing a second embodiment of the microheater having a non-heat generating portion according to the present invention, and shows a cross-sectional view in the longitudinal direction. The radial cross section of the portion where the non-heat generating wire 7 is present in the pipe of the connecting pipe 8 is the same as FIG. Components having the same functions as those of the conventional microheater shown in FIGS. 6 to 9 are denoted by the same reference numerals as those in FIGS.

  The difference between the microheater 2 having the non-heat generating portion of the present embodiment shown in FIG. 2 and the microheater 1 having the non-heat generating portion of the first embodiment is that the entire length of the non-heat generating wire 7 is in the pipe 8. It is. By doing so, the heat generation amount per unit length of the non-heat generating portion is smaller than that of the non-heat generating wire 7 not covered with the connecting pipe 8 of the first embodiment, as described above. Wasteful heat generation and power consumption are eliminated as compared with the micro heater 1 having the non-heat generating portion of the embodiment.

  Other features, effects, materials, and cross-sectional dimensions are the same as in the first embodiment, and a description thereof is omitted.

(Third embodiment)
FIG. 3 is a cross-sectional view showing a third embodiment of a microheater having a non-heat generating portion according to the present invention, FIG. 3 (a) is a longitudinal cross-sectional view, and FIGS. 3 (b) and 3 (c) are diagrams. It is CC cross section of 3 (a), DD cross section. However, the terminal sleeve 9 and the insulation coatings 13 and 15 of the lead wires 80 and 81 in FIG. 3A are drawn in outline, and FIG. 3B and FIG. 3C are obtained from FIG. Drawing at a large scale is the same as FIG. Also, the reference numerals in the figure denote the same components as those in the conventional microheater shown in FIGS. 6 to 9, as in FIGS. 6 to 9.

  The radial cross section of the portion where the non-heat generating wire 7 is present in the connecting tube 8 in FIG. 3A is the same as FIG. Components having the same functions as those of the conventional microheater shown in FIGS. 6 to 9 are denoted by the same reference numerals as those in FIGS.

  The difference between the microheater 3 having the non-heat generating portion of the third embodiment shown in FIG. 3 and the microheater 1 having the non-heat generating portion of the first embodiment is that the heating wire 6 and the non-heating wire 7 are the metal sheath tube 5. In the same manner as the microheater 21 having the conventional non-heat generating part shown in FIG. 9, the ratio of the cross-sectional dimensions is different from the point of reciprocation and the point that the terminal sleeve 9 is provided only on one side. Is a point.

  The structure in the terminal sleeve 9 is the structure shown in FIG. 1 of Patent Document 1, and the conductor 14 exposed from the insulating coatings 13 and 15 of the lead wires 80 and 81 for energization is provided on the terminal sleeve 9. , 15 are connected to each other in the same structure as the conventional micro heater 21 having a non-heat generating portion shown in FIG.

  Regarding the cross-sectional shape, the outer diameter of the metal sheath tube 5 of the present embodiment is 3.2 mm, the inner diameter is 2.56 mm, the outer diameter of the heating wire 6 and the non-heating wire 7 is 0.31 mm, and the thickness of the connecting tube 8 is The outer diameter of the connecting tube 8 is 0.15 mm and 0.61 mm. The inner diameter of the metal sheath tube 5 and the outer diameter of the heating wire 6 are the microheater 20 having the outer diameter of the conventional metal sheath tube 5 shown in FIG. 7 of 3.2 mm and the conventional metal sheath shown in FIG. In accordance with the standard inner diameter of the metal sheath tube 5 and the standard outer diameter of the heating wire 6 and the non-heating wire 7 of the microheater 21 having the non-heating portion with the outer diameter of the tube 5 of 3.2 mm. Yes.

  Other features, effects, and materials are the same as in the first embodiment, and the shape of the boundary between the heating wire 6 and the non-heating wire 7 is also the same as in FIG.

(Fourth embodiment)
FIG. 4 is a cross-sectional view showing a fourth embodiment of a microheater having a non-heating portion according to the present invention, and shows a cross-sectional view in the longitudinal direction. The radial cross section of the portion where the non-heat generating wire 7 is present in the pipe of the connecting pipe 8 is the same as FIG. Components having the same functions as those of the conventional microheater shown in FIGS. 6 to 9 are denoted by the same reference numerals as those in FIGS.

  The difference between the microheater 4 having the non-heat generating portion of the present embodiment shown in FIG. 4 and the microheater 3 having the non-heat generating portion of the third embodiment is that the entire length of the non-heat generating wire 7 is in the pipe 8. It is. By doing so, the heat generation amount per unit length of the non-heat generating portion is smaller than that of the non-heat generating wire 7 not covered with the connecting pipe 8 of the third embodiment, as described above. Wasteful heat generation and power consumption are eliminated as compared with the microheater 3 having the non-heat generating portion of the embodiment.

  Other features, effects, materials, and cross-sectional dimensions are the same as in the first embodiment, and a description thereof is omitted.

  As described above, the finished diameter of the microheater cable in the four embodiments, that is, the outer diameter of the metal sheath tube 5 is 3.2 mm, but the mainstream of the microheater cable conventionally used in the industry is 1.6 mm to The microheater cable of the microheater having a non-heat generating portion according to the present invention may have the same outer diameter as before, and the diameter of the heating wire 6 and the non-heating wire 7 according to the outer diameter. The inner and outer diameters of the tube 8 can be changed.

  The total length of the microheater cable and the position and length of the heat generating part are determined by the use conditions such as the distance between the terminal sleeve and the heating object, the size of the heating object, and the predetermined restrictions are Absent.

1 Micro heater with non-heat generating part (first embodiment)
2 Micro heater with non-heat generating part (second embodiment)
3 Micro heater with non-heating part (Third embodiment)
4 Micro heater with non-heat generating part (4th embodiment)
5 Metal sheath tube 6 Heating wire 7 Non-heating wire 8 Connecting tube 9 Terminal sleeve 12 Inorganic insulation powder 80, 81 Lead wire 13, 15 Lead wire insulation coating 14, 16 Lead wire conductor

Claims (4)

A metal sheath tube with no change in outer diameter in the axial direction ;
A heating wire that is housed in the metal sheath tube and generates Joule heat by energization using Nichrome as a material,
Accommodated in the metal sheath tube, made of copper and made of a non-heating wire having the same diameter as the heating wire;
A connecting tube housed in the metal sheath tube, made of metal and having an inner diameter substantially the same as that of the heating wire and the non-heating wire;
An inorganic insulating material powder filled between the metal sheath tube and the heating wire, the non-heating wire, and the connecting tube,
One end of the heating wire and one end of the non-heating wire are in contact with each other in the connecting pipe, and only the end portion of the heating wire that contacts the non-heating wire, and at least the heating wire of the non-heating wire, and an end portion of contact there with the connecting tube, the inner surface of該繋technique tube is in contact to the outer surface of the emitting heat rays and non-heating wire in the interior, the present portion of the non-heating wire, heat generating A microheater having a non-heat generating portion, characterized in that the non-heat generating portion has a smaller amount of heat generation than a portion of the wire outside the connecting pipe.   2. The microheater having a non-heat generating portion according to claim 1, wherein the non-heat generating wire in the connecting pipe is only an end portion of the non-heat generating wire that contacts the heat generating wire.   The microheater with a non-heat generating portion according to claim 1, wherein the non-heat generating wire in the connecting pipe is the entire length of the non-heat generating wire. 2. The microheater having a non-heat generating portion according to claim 1, wherein a material of the connecting pipe is nickel or copper.

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