JPH0216276Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a consumable thermocouple, and particularly to a consumable immersion thermocouple suitable for use in measuring the temperature of molten metal.

(Prior art) An example of a consumable immersion thermocouple that measures the temperature by immersing it in molten metal is the Utility Model Publication No. 43-29680.
Publication No. 45-9600, Publication No. 9600, Publication No. 45-
Publication No. 18236, Japanese Patent Publication No. 48-42200, etc. are known.

(Problem to be solved by the invention) In this type of thermocouple, the thermocouple wire is usually protected by a quartz glass tube, but due to its manufacturing process, the dimensions of the quartz glass tube, especially the inner and outer diameters, are precisely controlled. It is difficult to manufacture, and therefore, when positioning the glass tube with the support, the engaging part of the support with the glass tube may be damaged, or the glass tube may be damaged.
Alternatively, there have been problems in that the clearance between the two is too large, making it impossible to obtain the desired positioning accuracy, and that processing costs increase in order to improve the accuracy of the outer diameter of the glass tube.

(Structure of the invention) The present invention has been made in order to solve the above-mentioned problems. A thermocouple, in which one end of a quartz glass tube surrounding a thermocouple wire is engaged with and positioned in a resin support integrally provided with the housing and having a hollow portion having a cut and a stepped portion. A consumable thermocouple is provided.

The cut portion reliably grips the quartz tube even if the outer diameter of the quartz tube varies, and the stepped portion enables accurate positioning of the quartz tube in the longitudinal direction.

(Example) FIG. 2 is a schematic diagram of a consumable thermocouple according to the present invention, in which 1 is a thermocouple plug body (housing),
It is inserted and fixed into one end of an elongated protective tube 2 such as a paper tube. The protective tube 2 is made by cutting a paper tube base paper of approximately 0.7 mm into a ribbon shape, applying adhesive to the ribbon, and wrapping it spirally to a wall thickness of approximately 6 mm.

FIG. 1 is an enlarged sectional view showing a portion of the housing 1 in FIG. 2. Reference numeral 3 denotes a relatively thin cylindrical housing body with a bottom, and a flange 12 is provided at the outer end (left end in the figure). 4 is a U-shaped quartz glass tube with an outer diameter of about 3 mm, inside which is a thin thermocouple wire 5 made of platinum wire and platinum/rhodium wire.
5 is passed through the tube 4, and the joint portion of both wires 5, 5 constituting a hot junction is located approximately at the center of the U-shape of the tube 4.
The thermocouple wires 5, 5 are connected to connector pins 6, 6 made of compensating conductive wire material, and the connector pins 6, 6 are connectors that penetrate the bottom surface of the housing body 3 and are integrally molded and protrude outward from the bottom surface. It is bent along the body 7 to form connectors 8,8. The connectors 8, 8 are preferably connected to a complementary female connector (not shown), so that the thermoelectromotive force generated when the thermocouple is used is guided to the outside from the right end of the protective tube 2 in FIG.

A support 9 according to the invention projects inwardly from the bottom of the housing body 3. The support 9 has a first cavity 14 having a stepped portion 15 as shown in FIG.
, a second cavity 17 connected to the first cavity via the stepped portion, and the first and second cavities 1
4 and 17, and a hollow portion 18 having a cut 16 that diametrically passes through the holes 4 and 17, and a tapered surface 13 is provided on the inner surface of the distal end of the hollow portion 18. As shown, the cut 16 extends from the tip of the support 9 to the bottom surface or stepped portion 15 of the first cavity 14 and further to the cavity 1.
It extends in the axial direction to a position beyond the bottom surface of 7.
One end of the quartz glass tube 4 is inserted into the hollow portion 18 and held in position. In this example,
Next to the first cavity 14, a second cavity 17 having a smaller diameter than the first cavity is provided via a stepped part 15,
Although the cutout 16 is formed beyond the bottom of the second cavity 17, this configuration is not absolutely necessary. When the housing, that is, the support body 9 is molded from a relatively rigid resin, it is constructed as in this embodiment so that it can expand to accommodate the insertion of the quartz tube and easily receive it. However, if a resin material with relatively low rigidity is used, the second cavity 17 is not provided in order to provide sufficient clamping force to the quartz tube.

After the quartz glass tube 4 is positioned and held by the support 9, the interior of the housing body 3 is filled with cement 10 having fireproof and electrically insulating properties.
Cement 10 may be any commonly used alumina-rich cement. Reference numeral 11 denotes a metal cap, which is generally made of an extremely thin iron plate plated with tin. The cap 10 has a hat shape and is caulked and fixed to the flange 12 of the housing body 3.

In a preferred embodiment, the support 9 has an outer diameter of 4 to
5 mm, the depth of the tapered surface 13 is 1 to 1.5 mm, the first cavity 14 has an inner diameter of 2.5 to 3 mm, a depth of 3 to 2.5 mm, the second
The cavity 17 has an inner diameter of 2 to 2.5 mm and a depth of 5 mm or more, and the cut 16 has a width of 1 to 1.5 mm and a depth of 10 mm or more. One end of the quartz glass tube 4 is inserted into the first cavity 14, is positioned by hitting the stepped portion 15, and is clamped by the elastic force of the support 9, but the clamping force at that time is are the material, wall thickness, and cut 1 of the support body 9
By appropriately selecting the depth etc. of the quartz glass tube 6, a desired clamping force can be obtained even if the outer diameter of the quartz glass tube 4 changes. Note that the width of the cut 16 becomes smaller as it approaches the outer end in the completed molding state due to the thermal contraction of the resin, which is advantageous for clamping.

The material of the support body 9 is styrene resin, its diameter is 4.5 mm, the first cavity 14 has an inner diameter of 2.8 mm and a depth of 3 mm, the second cavity 17 has a depth of 7 mm, and the cutout 16 is 12 mm.
mm, and when the housing body 3 is molded,
A quartz glass tube 4 having an outer diameter of 3 mm±0.3 mm could be easily inserted using a mechanical insertion device and could be securely positioned and clamped. This made it possible to maintain a constant amount of protrusion of the quartz glass tube after cement fixation. Furthermore, the production tolerance of the quartz glass tube can be made sufficiently large, making it possible to reduce the price by about 20%. In addition, since the tapered surface 13 serves as a guide surface, it has become possible to insert and fix using a mechanical method.
The insertion process time was reduced to about 1/3 compared to the manual insertion method.

During use, a holding rod (not shown) having a female connector at its tip is inserted into the protective tube 2 to electrically and mechanically connect it to the housing 1, and the thermocouple is immersed in the molten metal. The cap 11 is melted, and the thermocouple senses heat through the quartz glass tube 4, generating a thermoelectromotive force in the thermocouple wires 5, 5, which is taken out to the outside via the holding rod, and the temperature is detected. Ru.

(Effects of the invention) As mentioned above, according to the invention, (a) it is possible to increase the tolerance of the outer diameter of the quartz glass tube compared to conventional ones, and the price of the quartz glass tube is significantly reduced; It became possible to do so.

(b) Furthermore, as mentioned above, the cut 16 extends beyond the bottom of the cavity 14, that is, the stepped part 15, with which the end surface of the quartz tube is brought into contact, so that when inserting the quartz tube into the cavity 17, The hollow portion can be opened sufficiently to ensure that the end face of the quartz tube comes into contact with the stepped portion 15, so that the quartz tube can be accurately positioned in the longitudinal direction. Thereby, the amount of protrusion of the quartz glass tube after cement fixation can be maintained accurately. Further, since the stepped portion 15 is shaped to receive the end face of the quartz tube over almost its entire circumference, the posture when the quartz tube is installed is stable, and the quartz tube can be installed at an angle with respect to the support 9. This prevents defects such as poor fixation.

(c) Mechanical insertion and fixation became possible, significantly improving productivity.

[Brief explanation of drawings]

Fig. 1 is a longitudinal cross-sectional view showing the main parts of the consumable thermocouple according to the present invention, Fig. 2 is a schematic longitudinal cross-sectional view of the consumable thermocouple according to the present invention, and Fig. 3 is a longitudinal cross-sectional view and an end view of the support. . DESCRIPTION OF SYMBOLS 1... Housing, 2... Protection tube, 3... Housing body, 4... Quartz glass tube, 5, 5... Thermocouple wire, 9... Support body, 18... Hollow part, 14...
...First void, 15...Stepped portion, 16...Cut, 13...Tapered surface.

Claims (1)

[Claims for Utility Model Registration] 1. A consumable device constructed by inserting and fixing a temperature measuring element into one end of a protective tube, which has a U-shaped quartz glass tube with a thermocouple wire inserted into a housing with an open end. In the type thermocouple, a strut extending from the bottom surface of the housing toward the opening side is integrally formed in the housing, a hole is formed from the tip of the strut to a predetermined depth in the axial direction, and the inner surface of the tip of the strut is formed. A tapered surface is provided on one end of the quartz tube, and a groove extending in the axial direction from the tip of the column to a position beyond the bottom of the hole is formed through the column in the diametrical direction. A consumable thermocouple characterized by being attached to the bottom of a hole, positioning and holding the quartz tube. 2. The hole communicates with the first hole via a first hole extending from the tip of the support column to a predetermined depth in the axial direction, and a step formed at the bottom of the first hole, and a second hole having a smaller diameter than the first hole and extending to a predetermined position in the direction, the quartz tube is abutted against the step, and the groove extends beyond the bottom surface of the second hole. ing,
A consumable thermocouple according to claim 1 of the utility model registration claim.