JP5368632B1 - Sheath thermocouple terminal head - Google Patents

Abstract

  The sheath thermocouple terminal head according to the present invention includes an outer frame body having a through hole for inserting a base end portion of the sheath thermocouple at a bottom portion, and a terminal fixture (6) provided in the outer frame body. And a pair of connection fittings (7) fixed to the terminal fixture, so that the cut surface of the sheath thermocouple is at the same position as the surface of the terminal fixture on the side where the connection fixture is provided. In addition, the terminal fixture holds the sheath thermocouple through a through hole formed in the terminal fixture, and the filling region of the insulating material powder at the proximal end of the sheath thermocouple is removed to the inside of the cut surface and sealed. The material (16) is sealed so that a recess is formed at the base end of the sheath thermocouple, and the ends of the pair of thermocouple wires are exposed in the recess, and the compensating lead wire is connected by the wiring screw (8). It is fixed to the connecting bracket, and the pair of connecting brackets bypass the sheath ( Each have a d), a portion of the fitting of the plate-like fitting, characterized in that it is connected by laser welding at the ends and vertical position of the pair of thermocouple wires.

Description

  The present invention relates to a sheath thermocouple terminal head for connecting a thermocouple element of a sheath thermocouple used in a highly corrosive gas atmosphere such as an incinerator, a blast furnace, and a heavy oil boiler, and a compensation conductor.

  A sheathed thermocouple is a metal sheath that contains a thermocouple wire with an inorganic insulating material powder such as magnesia or alumina interposed in a metal sheath, and is wired to guide the thermocouple wire and its signal to the receiver. There is a terminal head (also called a terminal box) as a mechanism for connecting the compensating lead wire.

  A structural example of a conventional terminal head is shown in FIGS. 4 (a) is a longitudinal sectional view of a connection structure between a conventional sheath thermocouple 2 and a terminal head 1, FIG. 4 (b) is a CC arrow view, and FIG. 4 (c) is FIG. It is DD sectional drawing of b). FIG. 5 is an external view of the outer frame 3 and the lid 4. FIGS. 5A, 5B, 5C, and 5D are a front view, a left side view, and a right side, respectively. It is a figure and a top view. In FIG. 4, the left half of the lid 4 is shown as an external view.

  As shown in FIGS. 4A to 4C, one end of the thermocouple wire 13 is exposed in the through hole of the metal mounting screw 5 screwed into the bottom opening of the outer frame 3. A sheath thermocouple 2 is inserted.

  In order to prevent the sheath thermocouple 2 from rotating in the circumferential direction, the sheath 14 of the sheath thermocouple 2 is welded to a cylindrical ridge 11 provided on the upper surface of the mounting screw 5 (see welded portion 12). .

  Inside the terminal head 1, a terminal plate 61 made of an electrical insulating material is attached to the outer frame body 3 by a plurality of fixing screws 101.

  The pair of thermocouple wires 13 exposed from the sheath 14 is covered with an insulating tube 21 in order to prevent contact with each other. The ends of the pair of thermocouple wires 13 inserted through the central through hole of the terminal plate 61 are connected to the terminal fittings 71 and 71 by wiring screws 9. The terminal fittings 71 and 71 are fixed to the terminal plate 61 by screws 102 and 102, respectively. Each terminal fitting 71, 71 is provided with another wiring screw 8, 8, and the wiring screw 8, 8 is compensated from a receiver (not shown) inserted from the side opening 17 of the outer frame 3. Conductor is connected.

  A lid 4 is screwed to the outer frame body 3, and the lid 4 is removed and wiring to the terminal fitting 71 is performed. As shown in FIGS. 5A to 5D, the chain 4 is lost by connecting the chain fixing screw 19 attached to the outer frame 3 and the chain fixing screw 20 attached to the lid 4 with a chain 18. Is to prevent.

  FIGS. 6A to 6D are longitudinal sectional views showing the processing steps of the proximal end of the sheath thermocouple, and FIG. 6E is a transverse sectional view of the sheath thermocouple. 6A, by cutting the proximal end of the sheath 14 of the sheath thermocouple 2 and removing the inorganic insulating material powder 15 therein, a pair of thermocouples are obtained as shown in FIG. 6B. The end of the strand 13 is stripped.

  Subsequently, as shown in FIG. 6C, a depression is formed in the inorganic insulating material powder 15 at the end of the sheath 14 by blasting or the like. Then, as shown in FIG. 6D, the formed depression is filled with a sealing material 16 such as epoxy resin and cured. The sheath thermocouple 2 formed in this way is inserted into the outer frame 3 from the through hole of the mounting screw 5 as described above. The sealing material 16 is for preventing moisture from entering the filled portion of the inorganic insulating material powder 15 and deteriorating the insulation.

  As described above, the terminal plate 61 to which the terminal fittings 71 and 71 are attached is fixed in the outer frame 3, and the thermocouple wire exposed on the terminal fitting is screwed. Such a structure is common to conventional sheathed thermocouples with terminal heads. For example, it is a thermocouple terminal head that uses an insulator having two through holes through which a pair of thermocouple wires pass instead of an insulating powder. In Patent Document 1, it is fixed to an insulator (terminal plate). A terminal head is disclosed in which a temperature measuring element (thermocouple wire) is connected to the terminal block (screw terminal fitting). Non-Patent Document 1 discloses a terminal head 40 in which a thermocouple wire 43 is screwed to a terminal fitting 42 fixed to a terminal plate 41 as shown in FIG. Since any of the terminal heads described in these documents has a structure in which the exposed thermocouple element is screwed to the terminal fitting, the sheath thermocouple shown in FIGS. 6 (a) to 6 (d) is used. The base end machining is an indispensable work for connecting the thermocouple wire to the terminal fitting of the terminal head.

Japanese Utility Model Publication No. 63-135134

“The correct way to use a new thermometer” edited by Japan Electric Measuring Instruments Manufacturers Association, Fig.2.14

  When a sheath thermocouple having a small diameter (for example, 3.2 to 8 mm) is used in a highly corrosive gas atmosphere, since the sheath is thin, corrosion occurs to the inside of the sheath in a short period of use, and the sealing function is lost. For this reason, in a highly corrosive gas atmosphere such as an incinerator, a blast furnace, or a heavy oil boiler, a sheath thermocouple having a large diameter and a large sheath is often used.

  However, in order to expose the end of the thermocouple wire, the operation of cutting the end of the sheath when moving from FIG. 6 (a) to FIG. 6 (b) is performed with a small-diameter sheath thermocouple having an outer diameter of about 8 mm or less. This can be easily done by using a small hand-held tube cutter or the like to cut the base of the sheath to be cut and removing the sheath. It cannot be peeled off by a simple method, and requires a labor and time-consuming work of scraping and removing the entire sheath to be cut by a lathe.

  Moreover, even if the thermocouple wire is stripped to the state shown in FIG. 6B, the sheath thermocouple having a large diameter exceeding 20 mm has a strand diameter of 3 mm or more, and the strand diameter is large. It cannot be bent easily, and it is difficult to fix it to the terminal fitting with a wiring screw.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to easily connect a thermocouple wire to a connection fitting even when a large-diameter sheath thermocouple is used. An object of the present invention is to provide a sheathed thermocouple terminal head that can improve the efficiency of connection work.

The sheath thermocouple terminal head according to the present invention includes a thermocouple element and a pair of compensation of a sheath thermocouple in which a pair of thermocouple elements is accommodated via an insulating powder filled in a cylindrical sheath. A sheathed thermocouple terminal head for connecting a conductor,
An outer frame body having a through-hole for inserting a base end portion of the sheath thermocouple at the bottom, a terminal fixture provided in the outer frame body, and a pair of connections fixed to the terminal fixture With metal fittings,
The terminal so that the cut surface of the sheath thermocouple cut so as to cross the axial direction of the sheath thermocouple is at the same position as the surface of the terminal fixture on the side where the connection fitting is provided. The fixture holds the sheath thermocouple through a through hole formed in the terminal fixture,
The filling region of the insulating material powder at the proximal end of the sheath thermocouple is removed inward from the cut surface, and sealed with a sealing material in the form of a recess at the proximal end of the sheath thermocouple, The ends of the pair of thermocouple wires are exposed in the depression,
The compensation lead wire on the plus side of the pair of compensation lead wires is fixed to one connection fitting of the pair of connection fittings by a wiring screw, and the compensation lead wire on the minus side of the pair of compensation lead wires is fixed to the pair of connection fittings by a wiring screw. It is fixed to the other connection bracket,
Each of the pair of connection fittings has a detour portion that detours the sheath so as not to contact the sheath,
The plate-shaped part of the one connection fitting of the pair of connection fittings is connected by laser welding in a state perpendicular to the end of the thermocouple strand on the plus side of the pair of thermocouple strands, and the pair of connections The gist is that a part of the plate of the other connecting metal fitting of the metal fitting is connected by laser welding in a state perpendicular to the end of the thermocouple element on the minus side of the pair of thermocouple elements.

  The “same position” means that the cutting surface of the sheath thermocouple and the surface of the terminal fixture are exactly the same position, and the position where the distance between the cutting surface and the surface is substantially the same (for example, the distance) Is within 5 mm). In addition, the above “vertical state” means that the plate-shaped part of the connection fitting and the end of the thermocouple element are completely perpendicular, and the part and the end are substantially perpendicular (the part And the meaning that the acute angle formed by the terminal is, for example, 80 ° or more and less than 90 °.

  According to the sheath thermocouple terminal head according to the present invention, the filling region of the insulating material powder at the proximal end of the sheath thermocouple is removed inside the cut surface, and a recess is formed at the proximal end of the sheath thermocouple by the sealing material. By sealing in the formed form, the ends of the pair of thermocouple wires can be exposed in the recess.

  By adopting such a configuration, it is necessary in the present invention to cut off the end of the thick sheath, which has been a laborious and time-consuming work when using a conventional sheathed thermocouple terminal head for a large-diameter sheathed thermocouple. And not.

Further, the cut surface of the sheath thermocouple cut so as to cross the axial direction of the sheath thermocouple as described above is located at the same position as the surface of the terminal fixture on the side where the connection fitting is provided. The sheath thermocouple is held in the terminal fixture through its through hole, and the plate-shaped part of the connection fitting is connected by laser welding in a state perpendicular to the end of the thermocouple wire. Therefore, there is no need to bend a thick thermocouple wire to connect it to the connection fitting, which has been a difficult task when using a conventional sheathed thermocouple terminal head for a large-diameter sheath thermocouple. Laser welding of the plate part of the connection fitting and the thermocouple wire is only necessary by irradiating the welding laser beam from the upper part of the plate shape of the connection fitting contacting the thermocouple element. Absent.
Further, since each of the pair of connection fittings has a detour portion that bypasses the sheath so as not to contact the sheath, the connection fitting does not contact a sheath having a different potential from the thermocouple element. The measurement signal of the thermocouple is not affected by the sheath potential.

  Also, since the insulating powder removal region at the base end of the sheath thermocouple is sealed with a sealing material, it is possible to prevent insulation from deteriorating due to moisture entering the inside of the sheath thermocouple, as in the past. It is.

  In this invention, it is preferable that the inner wall of the said through-hole of the said terminal fixture and the sheath outer wall in the said sheath thermocouple are adhere | attached with the adhesive agent. The sheath thermocouple does not rotate in the circumferential direction with respect to the terminal fixture and does not move in the axial direction / radial direction, and the connection between the thermocouple element and the connection fitting is disconnected by these rotations and movements. This is because it can be prevented.

  In the present invention, at least one ridge or groove is provided on the inner surface of the outer frame body along the axial direction of the sheath thermocouple, and the groove or the groove is engaged with the ridge on the outer surface of the terminal fixture. And the terminal fixture is in the state in which the projection or the groove of the outer frame is engaged with the groove or the projection of the terminal fixture. It is preferable to be fixed to. This is because the terminal fixture can be prevented from rotating or moving with respect to the outer frame.

  According to the sheath thermocouple terminal head according to the present invention, since the thermocouple element can be connected to the connection fitting without bending the end of the thermocouple wire, even a large-diameter sheath thermocouple is similar to a small-diameter sheath thermocouple. The work of connecting the pair of wires to the connection fitting becomes easy. In addition, since it is not necessary to cut off the sheath in the end processing of the sheath thermocouple, even a large-diameter sheath thermocouple does not require labor and time for end processing, and work efficiency can be improved.

It is a longitudinal section showing a sheath thermocouple terminal head concerning the present invention. (A) is an AA arrow top view of FIG. 1, (b) is BB sectional drawing of (a). (A)-(c) is sectional drawing which shows the process of the edge part process of the sheath thermocouple which concerns on this invention, (d) is a cross-sectional view of a sheath thermocouple. (A) is the longitudinal cross-sectional view of the connection structure of the conventional sheathed thermocouple and a terminal head, (b) is a CC arrow top view of (a), (c) is D of (b) It is -D line longitudinal cross-sectional view. It is the external view of the outer frame body and lid | cover of the conventional terminal head, (a) is a front view, (b) is a left view, (c) is a right view, (d) is a top view. (A)-(d) is sectional drawing which shows the process process of the edge part processing of the conventional sheathed thermocouple, (e) is a cross-sectional view of a sheathed thermocouple. It is a figure which shows the other example of the conventional terminal head.

  Hereinafter, the present invention will be described in detail based on the embodiments shown in the drawings.

1. Overall Configuration of Sheath Thermocouple Terminal Head FIG. 1 is a longitudinal sectional view showing a sheath thermocouple terminal head 1 according to the present invention. In FIG. 1, the left half of the lid 4 is shown as an external view. In the following drawings, components having the same reference numerals as those in FIGS. 4 to 6 are given the same reference numerals, and description thereof may be omitted.

  As shown in FIG. 1, a pair of thermocouple wires 13 is accommodated via an insulating material powder 15 filled in a cylindrical sheath 14 of the sheath thermocouple 2.

  The sheath thermocouple terminal head 1 is also referred to as a terminal box, and is used to connect the thermocouple element 13 of the sheath thermocouple 2 and a compensation conductor (not shown), and the base end of the sheath thermocouple 2 is inserted through the sheath thermocouple terminal head 1. An outer frame body 3 provided with a through hole 3a for the bottom, a terminal fixture 6 provided in the outer frame body 3, and a pair of connection fittings 7 and 7 fixed to the terminal fixture 6. It is mainly equipped with.

  When the diameter of the through-hole 3a of the outer frame 3 is significantly larger than the outer diameter of the sheath thermocouple 2, the mounting screw 5 shown in FIG. Also good.

  The outer shape of the sheath thermocouple terminal head according to the present invention is basically the same as the conventional one shown in FIG. 5, and the cover 4 of the sheath thermocouple terminal head 1 is attached to the outer frame 3 by screwing. The end of the chain 18 is connected to chain fixing screws 19 and 20 provided on the outer frame 3 and the lid 4 respectively, thereby preventing the lid 4 from being lost.

2. Connection between Thermocouple Wire and Connection Fitting FIG. 2A is a plan view taken along the line AA in FIG. 1, and FIG. 2B is a cross-sectional view taken along line BB in FIG.

  As shown in FIG. 2, the connection fitting 7 is formed of a band-shaped metal plate, and as shown in FIG. 2B, a concave portion 7a bent in a U-shape is provided at the center thereof. 7a is embedded and fixed in a terminal fixture 6 made of an electrical insulating material.

  One end portion 7b of the connection fitting 7 is substantially perpendicular to the end of the thermocouple wire 13 via a detour portion 7d that bypasses the cutting edge 14a so as not to contact the cutting edge 14a on the proximal end side of the sheath 14. Each is connected.

  One end 7 b of the connection fitting 7 and the end of the thermocouple element 13 are connected to each other at a contact portion (laser welding portion) 22 by laser welding. In addition, in order to perform laser welding, what is necessary is just to irradiate a laser beam from the upper part of the connection metal fitting 7, and it is not a difficult operation | work. On the other hand, one end of a compensation conductor (not shown) is connected to the other end 7 c of the connection fitting 7 by a wiring screw 8.

  With the configuration as described above, the thermocouple element 13 and the compensating conductor are connected to each other in the connection fitting 7 without the connection fitting 7 coming into contact with the sheath 14 whose potential may be different from that of the thermocouple strand 13. One of the connection fittings 7 and 7 connects the plus-side thermocouple element 13 and the plus-side compensation conductor, and the other of them connects the minus-side thermocouple element 13 and the minus-side compensation conductor. , And the thermoelectromotive force of the thermocouple element 13 is transmitted to a receiver (not shown) via the compensation conductor.

  The shape of the connection fitting 7 in FIG. 2 shows an example, and is not limited to this. A part of the connection fitting 7 is fixed to the terminal fixture 6 to avoid contact with the sheath 14. Any connection fitting 7 having a shape that can be obtained and that can be laser-welded with the thermocouple element 13 and that has a mechanism capable of connecting a compensating conductor is included in the technical scope of the present invention.

  As described above, in the present invention, it is necessary to bend the thick thermocouple wire 13 of the large-diameter sheath thermocouple, which has been difficult when the conventional sheath thermocouple terminal head is used for the large-diameter sheath thermocouple. Therefore, even with a large-diameter sheath thermocouple, the one end portion 7b of the connection fitting 7 can be easily connected to the end of the thermocouple wire 13 in the same manner as the small-diameter sheath thermocouple.

  The inner wall of the through hole 6a of the terminal fixture 6 for inserting the sheath thermocouple 2 and the outer wall of the sheath 14 are bonded with an adhesive. Therefore, the sheath thermocouple 2 does not rotate in the circumferential direction with respect to the terminal fixture 6 and does not move in the axial direction or the radial direction. There is no risk of welding coming off.

  The upper flange 6 b of the terminal fixture 6 is fixed to the outer frame 3 of the sheath thermocouple terminal head 1 with screws 10. For this reason, the terminal fixture 6 is prevented from rotating and moving with respect to the outer frame body 3.

  In addition to the above, in the present invention, the ridge 23b is provided on the inner surface of the outer frame 3 along the vertical direction (the axial direction of the sheath thermocouple 2), and this is provided on the outer surface of the lower cylindrical portion of the terminal fixture 6. The vertical groove 23a is engaged. In FIG. 2A, in order to show the engagement state between the groove 23a of the terminal fixture 6 and the ridge 23b of the outer frame 3, the groove 23a and the ridge 23b on the back are also shown by dotted lines for convenience. Show.

  Since such an engagement structure is provided, a rotational force in the circumferential direction is applied to the sheath thermocouple 2, and when the sheath thermocouple 2 has a large diameter, a large rotational moment is applied to the terminal fixture 6 due to the large diameter. Even if transmitted from the pair, the terminal fixture 6 does not rotate with respect to the outer frame body 3 by the double means of the screw fixing of the terminal fixture 6 to the outer frame body 3 and the engagement structure.

  The shape of the terminal fixture 6 is not limited to that shown in FIG. 2, and there is a through-hole for inserting the sheath thermocouple 2, and the sheath outer wall and the inner wall of the through-hole can be bonded. What is necessary is just to be provided with the groove part engaged with the protruding item | line 23b of the outer frame body 3. FIG.

  Moreover, as said engaging structure, a groove part is provided in the vertical direction in the inner surface of the outer frame 3, and this shall be engaged with the convex strip provided in the outer surface of the lower cylindrical part of the terminal fixture 6. FIG. You can also.

3. Processing Process of End Processing of Sheath Thermocouple FIGS. 3A to 3C are longitudinal sectional views showing a processing process of end processing of the sheath thermocouple 2 according to the present invention, and FIG. It is a cross-sectional view of a pair.

  As shown in FIGS. 3A and 3D, the sheath thermocouple 2 includes a sheath 14, a pair of thermocouple wires 13 housed in the sheath 14 in a non-contact manner, and a sheath 14. And the inorganic insulating material powder 15 filled in. Note that cutting to bring the base end of the sheath thermocouple 2 into the state shown in FIG. 3A is easy even when the diameter is large, by using a motor-driven cutting device.

  First, the dent 15a of FIG. 3B is formed by digging into the inorganic insulating material powder 15 at the base end of the sheath 14 by blasting or the like. Subsequently, in order to prevent moisture from entering the sheath 14 and the inorganic insulating material powder 15, a sealing material 16 such as an epoxy resin is poured into the recess 15 a and cured. Here, by making the amount of the sealing material 16 poured into an amount smaller than the volume of the recess 15a, the surface of the sealing material 16 is positioned below the cut surface at the base end portion of the sheath thermocouple, as shown in FIG. . Thereby, the terminal of the thermocouple strand 13 can be exposed in the sheath thermocouple cut surface.

  In the conventional sheathed thermocouple terminal head, in order to expose the end of the thermocouple wire, the operation of cutting the end of the sheath when moving from FIG. 6 (a) to FIG. 6 (b) is about 8 mm in outer diameter. The following small-diameter sheath thermocouples could be easily done by using a small hand-held tube cutter, etc., and cutting the base of the sheath to be cut out and removing the sheath. Then, since the sheath becomes thick, it cannot be peeled off by such a method, and a labor and time-consuming operation of scraping and removing the entire sheath cut by a lathe is necessary.

  In the present invention, since the end of the thermocouple wire 13 exposed at the cut surface of the sheath thermocouple can be used as described above, conventionally, a large-diameter sheath thermocouple has been time-consuming and time-consuming work. The operation of peeling off the thick sheath is not required in the present invention.

4). Assembly Order First, the sheath thermocouple 2 processed as shown in FIG. 3C is inserted into the single outer frame body through the through hole 3a provided at the bottom of the outer frame body 3.

  Next, after an adhesive made of epoxy resin is applied to a predetermined region on the outer surface of the sheath 14, the through hole 6 a of the terminal fixture 6 is applied until the end of the thermocouple element 13 contacts one end 7 b of the connection fitting 7. The sheath thermocouple 2 is inserted, and the terminal fixture 6 and the sheath thermocouple 2 are bonded in this state.

  Subsequently, the connection fitting 7 and the end of the thermocouple element 13 are welded and connected by irradiating a laser beam for welding from above the contact portions 22.

  And it integrated with the sheath thermocouple 2 so that the two groove parts 23a formed in the outer surface of the terminal fixture 6 may each be engaged with the two convex strips 23b formed in the inner surface of the outer frame 3. The terminal fixture 6 is pulled into the outer frame 3, and two metal fixing screws 10 are inserted into the screw holes of the flange 6 b of the terminal fixture 6 to fix the terminal fixture 6 to the outer frame 3.

  Finally, the compensation conductor is inserted into the outer frame 3 from the opening 17 on the side of the outer frame 3, the tip of the compensation conductor is fixed to the connection fitting 7 with the wiring screw 8, and the lid 4 is attached to the outer frame 3. And the outer frame 3 is closed.

  The above is a mode for carrying out the present invention. However, the present invention is not limited by the above embodiment as a matter of course, and it is needless to say that the present invention can be carried out with appropriate modifications within a range that can meet the gist of the present invention. All of these are possible within the scope of the present invention.

  Hereinafter, the present invention will be described more specifically with reference to examples. The present invention is not limited by the following examples, and can of course be implemented with appropriate modifications within a range that can be adapted to the above-described gist. Included in the range.

  The sheath thermocouple 2 of the embodiment according to the present invention has a large diameter of 22 mm (outer diameter), the thickness of the sheath 14 is 2.2 mm, and the diameter of the thermocouple wire 13 is 3.2 mm. is there.

  Magnesia powder was used as the inorganic insulating material powder 15, stainless steel was used as the material of the sheath 14, and the type of the thermocouple element 13 was K type. In addition, the type of the tip temperature measuring section of the sheath thermocouple 2 is an ungrounded type, and its base end is processed in the procedure shown in FIG. 3 described above, and an epoxy resin is used as the sealing material 16.

  The terminal fixture 6 uses PBT (Polybutyleneterephthalate) resin as a material. When the terminal fixture 6 is injection-molded, the terminal fixture 6 is fixed by embedding the concave portion 7a of the connection fitting 7 made of a belt-like stainless steel plate. did. The outer frame 3 and the lid 4 of the sheath thermocouple terminal head 1 were made of aluminum die cast.

  The structure of the sheath thermocouple terminal head according to the present invention is not limited to the case of connecting the thermocouple element wire of the sheath thermocouple and the compensating lead wire as described above. It can also be used effectively to connect a conducting wire to be fed.

DESCRIPTION OF SYMBOLS 1 Sheath thermocouple terminal head 2 Sheath thermocouple 3 Outer frame body of terminal head 3a Through hole 4 Terminal head lid 5 Mounting screw 6 Terminal fixture 6a Through hole 7 Connecting metal fitting 7a Concave 7b One end 7c The other end 7d Detour Part 8 Wiring screw for compensating lead wire 9 Wiring screw for thermocouple element wire 10 Screw for fixing terminal fixing 11 Projection of mounting screw 12 Welding part 13 Thermocouple element wire 14 Sheath 15 Inorganic insulating material powder 16 Sealing material 17 Side opening of terminal head outer frame 18 chain 19 Chain fixing screw for terminal head outer frame 20 Chain fixing screw for terminal head lid 21 Insulating tube 22 Laser welded part (contact part)
23a Groove 23b Projection 61 Terminal plate 71 Terminal fitting 101 Terminal plate fixing screw 102 Terminal fitting fixing screw

Claims (3)

A sheath thermocouple terminal head for connecting the thermocouple element and a pair of compensating conductors of a sheath thermocouple in which a pair of thermocouple elements is accommodated via an insulating powder filled in a cylindrical sheath There,
An outer frame body having a through-hole for inserting a base end portion of the sheath thermocouple at the bottom, a terminal fixture provided in the outer frame body, and a pair of connections fixed to the terminal fixture With metal fittings,
The terminal so that the cut surface of the sheath thermocouple cut so as to cross the axial direction of the sheath thermocouple is at the same position as the surface of the terminal fixture on the side where the connection fitting is provided. The fixture holds the sheath thermocouple through a through hole formed in the terminal fixture,
The filling region of the insulating material powder at the proximal end of the sheath thermocouple is removed inward from the cut surface, and sealed with a sealing material in the form of a recess at the proximal end of the sheath thermocouple, The ends of the pair of thermocouple wires are exposed in the depression,
The compensation lead wire on the plus side of the pair of compensation lead wires is fixed to one connection fitting of the pair of connection fittings by a wiring screw, and the compensation lead wire on the minus side of the pair of compensation lead wires is fixed to the pair of connection fittings by a wiring screw. It is fixed to the other connection bracket,
Each of the pair of connection fittings has a detour portion that detours the sheath so as not to contact the sheath,
The plate-shaped part of the one connection fitting of the pair of connection fittings is connected by laser welding in a state perpendicular to the end of the thermocouple strand on the plus side of the pair of thermocouple strands, and the pair of connections A plate-shaped part of the other connecting metal fitting of the metal fitting is connected by laser welding in a state perpendicular to the end of the negative thermocouple element of the pair of thermocouple elements. Terminal head.   The sheath thermocouple terminal head according to claim 1, wherein an inner wall of the through hole of the terminal fixture and an outer wall of the sheath of the sheath thermocouple are bonded with an adhesive. At least one ridge or groove is provided on the inner surface of the outer frame body along the axial direction of the sheath thermocouple, and the outer surface of the terminal fixture is engaged with the groove or the groove engaged with the ridge. Ridges are provided,
3. The terminal fixture is fixed to the outer frame body in a state where the ridges or the groove portions of the outer frame body are engaged with the groove portions or the ridge portions of the terminal fixture. 4. The sheath thermocouple terminal head described in 1.

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