JP4812455B2 - Protective tube for molten metal temperature measurement and molten metal thermometer - Google Patents

Description

  The present invention relates to a molten metal temperature measuring protective tube and a molten metal thermometer.

  In order to measure the molten metal temperature of non-ferrous metals such as aluminum, zinc, and copper, and alloys thereof, protective tubes that contain temperature detection elements such as thermocouples are conventionally known. This molten metal temperature measuring tube is used by being immersed in the molten metal. For example, it is difficult to react with a metal oxide such as silica, alumina, alumina / silica, zirconia, or molten metal such as silicon carbide or silicon nitride. It is obtained by applying a coating material obtained by dispersing a material powder in an aqueous solution such as water glass or silica sol / alumina sol to a tube surface such as a cast iron tube and drying and solidifying it.

  However, such a protective tube may cause cracking or peeling in the coating material due to an impact during handling or a difference in thermal expansion between the cast iron tube during temperature measurement, or may adhere to the coating material. When removing and cleaning the molten oxide, the coating material may be peeled off or lost. For this reason, for example, when used for measuring the temperature of a melting furnace or holding furnace in aluminum die casting, the coating material needs to be reapplied approximately every one week, which is not only cumbersome but also drying after application. Since processing is required, spare parts must be prepared so as not to hinder the operation, and there is a problem in terms of cost.

In addition to the above-described protection tube for the temperature detection element, a ceramic protection tube such as silicon nitride is also known (for example, Patent Document 1). Ceramic protection tubes can be used for a long time while immersed in the molten metal, which eliminates maintenance problems, but not only increases manufacturing costs, but also has the problem of being susceptible to mechanical shock. In addition, there is a possibility that damage may occur in an operation of attaching to a melting furnace or a holding furnace or an operation of removing attached molten oxide.
JP 2002-249380 A

  Accordingly, an object of the present invention is to provide a molten metal temperature measuring protective tube and a molten metal thermometer excellent in durability and impact resistance.

The object of the present invention is a molten metal temperature measuring protective tube capable of accommodating a temperature detecting element for measuring a molten metal temperature, a tube body having openings at both ends, and a ceramic cap for closing one end side of the tube body. And a reinforcing material that covers the tube main body and the cap, and the reinforcing material impregnates a base material sheet made of glass fiber with a glassy coating agent, and the entire surface of the base material sheet is coated with glass This is achieved by a molten metal temperature measuring protective tube formed by covering with a coating film of the agent.

In warm protective tube measuring the melt, the cap preferably includes an end surface abutting step portion of the tube body on the inner peripheral surface. In addition, it is preferable that the cap is attached to the pipe body via a flange portion provided on the outer peripheral surface of the pipe body. Further, the cap is preferably made of a silicon carbide material.

  The object of the present invention is achieved by a molten metal thermometer in which a temperature detecting element is accommodated in each of the above-described molten metal temperature measuring protective tubes.

  ADVANTAGE OF THE INVENTION According to this invention, the protective tube for molten metal temperature measurement and the molten metal thermometer which are excellent in durability and impact resistance can be provided.

  Hereinafter, actual forms of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a side view showing a partial section of a molten metal temperature measuring protective tube according to an embodiment of the present invention.

  As shown in FIG. 1, the molten metal temperature measuring protective tube 1 includes a tube body 10, a cap 20 that closes one end of the tube body 10, and a reinforcing member 30 that covers the tube body 10 and the cap 20. Yes.

  The pipe body 10 is made of a metal material such as ordinary steel, stainless steel, cast iron, and has openings at both ends. The tube body 10 has a cap 20 attached to one end side, and a temperature detection element (not shown) such as a thermocouple, a resistance temperature detector, or a thermistor is inserted from the other end side.

  As shown in an enlarged view in FIG. 2, the cap 20 has a ring-shaped step portion 22 on the inner peripheral surface, and the end surface of the pipe body 10 is in contact with the step portion 22. Since the cap 20 houses and protects the temperature measuring part of the temperature detecting element, the cap 20 is required to have excellent thermal responsiveness in order to quickly transmit the temperature of the molten metal. For this reason, the cap 20 is preferably made of ceramic. In particular, the silicon carbide (SiC) material has excellent properties such as strength, heat resistance, corrosion resistance, oxidation resistance, thermal conductivity, and availability. Therefore, it is preferable. The ceramic constituting the cap 20 is not necessarily required to be dense and dense, and can be manufactured at a low sintering temperature using a low-cost raw material. Although the height of the cap 20 is not specifically limited, For example, it is 20-100 mm. A soft paste-like refractory material such as a patching material or a castable material is supplied around the insertion portion of the tube main body 10 to the cap 20 to ensure that the molten metal enters the tube main body 10 and the cap 20. It is preferable to prevent it.

  As shown in FIGS. 1 and 2, the reinforcing member 30 is a base sheet 32 that is formed in a cylindrical shape so as to cover the outer peripheral surfaces of the pipe body 10 and the cap 20, and an application that covers the surface of the base sheet 32. And a film 34. In the present embodiment, the cap 20 is covered with the reinforcing material 30 so that the front end surface of the cap 20 is exposed in order to improve the thermal conductivity. However, the entire cap 20 may be covered. .

  The base material sheet 32 consists of glass fibers, such as a glass sleeve, a glass woven fabric, and a glass nonwoven fabric, and the glass composition of glass fiber can illustrate preferably E glass, S glass (T glass), etc. The base sheet 32 is set to have an inner diameter that is approximately the same as or slightly smaller than the outer diameter of the tube body 10, and comes into close contact with the outer surface of the tube body 10 after being attached to the tube body 10.

  The glass fiber gaps in the base sheet 32 are pre-impregnated with a heat-resistant glassy coating agent by application, dipping, or the like before being attached to the tube body 10. Examples of the heat resistant glassy coating agent include metal oxides such as silica, alumina, alumina / silica, zirconia, and refractory powders that hardly react with molten metal such as silicon carbide and silicon nitride. Silicate) or silica sol / alumina sol dispersed in an aqueous solution can be used. The refractory powder described above is preferably obtained by pulverizing a fibrous material in order to increase the coating strength of the coating material.

  The coating film 34 is formed on the surface of the base sheet 32 by applying a glassy coating agent having heat resistance. The heat-resistant glassy coating agent is preferably applied uniformly over the entire surface of the substrate sheet 32, and is preferably repeated a plurality of times with the viscosity adjusted appropriately. The thickness of the coating film 34 thus obtained from the surface of the base sheet 32 is preferably about 0.2 to 1.0 mm. Examples of the glassy coating agent applied to the surface of the base sheet 32 may be the same as the glassy coating agent impregnated in the base sheet 32.

  As shown in FIG. 3, the molten metal temperature-measurement protective tube 1 having the above-described configuration inserts the temperature detection element 40 and accommodates the temperature-measurement unit 42 so as to be positioned in the cap 20, thereby A total of 2 is obtained. The periphery of the temperature detection element 40 inside the tube body 10 and the cap 20 may be filled with a filler having good thermal conductivity and insulating properties such as magnesium oxide powder.

  The temperature detection element 40 uses a thermocouple in this embodiment, and uses a thermocouple wire covered with a plurality of insulated pipes, but a general-purpose sheathed thermocouple covered with a stainless steel pipe, etc. Further, other temperature detection elements such as a resistance temperature detector and a thermistor can also be used.

  According to the molten metal temperature measuring protective tube 1 of the present embodiment, the reinforcing material 30 covering the tube main body 10 includes a base material sheet 32 made of glass fibers impregnated with a heat-resistant glassy coating agent, and a base material sheet 32. And a coating film 34 of a heat-resistant glassy coating agent formed on the surface of the tube, it is possible to prevent deterioration due to penetration of the molten metal into the tube main body 10 and to prevent impact and Peeling and cracking of the coating agent due to thermal expansion can be prevented, and furthermore, peeling and loss of the coating agent when removing the adhered molten oxide can be prevented. As a result, durability and impact resistance are improved and long-term continuous use can be performed.

  In addition, since the vicinity of the temperature measuring portion 42 that particularly needs to be protected in the temperature detecting element 40 is covered with the ceramic cap 20 and the reinforcing material 30, the durability of the portion that is always immersed in the molten metal is more reliably ensured. Can be increased.

  Further, a step portion 22 is formed on the inner peripheral surface of the cap 20, and the end surface of the tube body 10 is in contact with the step portion 22, so that the joint portion between the tube body 10 and the cap 20 is brought into close contact. It is possible to prevent the molten metal from entering the cap 20 with certainty. Moreover, since the insertion length of the pipe | tube main body 10 to the cap 20 can be made constant, the dimensional accuracy of the protective tube 1 for molten metal temperature measurement can be improved.

  As mentioned above, although one Embodiment of this invention was explained in full detail, the specific aspect of this invention is not limited to the said embodiment. For example, the molten metal temperature measuring protective tube 1 of the present embodiment has a configuration in which a step portion 22 is formed on the inner peripheral surface of the cap 20 and the end surface of the tube main body 10 is in contact with the step portion 22. 4, the inner peripheral surface of the cap 20 is formed to be a tapered taper portion 24, and when the tube body 10 is pushed into the cap 20, the entire outer edge of the cap 20 is the inner periphery of the tube body 10. It can also be configured to be in close contact with the surface.

  Further, the molten metal temperature measuring protective tube 1 of the present embodiment is equipped with a ceramic cap 20 at one opening end of the tube main body 10, but uses a bottomed tube main body with one end closed. By doing so, a configuration without the cap 20 is also possible. In this case, it is preferable to cover the tube body with the reinforcing material 30 including the bottom portion that closes the tube body.

  Further, in the molten metal temperature measuring protective tube 1 of the present embodiment, the tube body 10 and the cap 20 are attached to the flange portion 18 provided on the outer peripheral surface in the vicinity of one end of the tube body 10 as shown in FIG. The cap 20 can be securely attached by this. In FIG. 5, the flange portion 18 has a ring-shaped holding portion 18a extending toward the end portion at the outer peripheral edge, and is configured to hold the outer peripheral surface of the cap 20 by the holding portion 18a. Further, a ring-shaped configuration that does not include the holding portion 18a may be used. If the flange portion 18 is configured to come into contact with the end surface of the cap 20, the insertion length of the tube body 10 into the cap 20 can be made constant without providing the step portion 22, and the molten metal temperature measuring protective tube. It is possible to reduce the variation of each product regarding the length of one.

It is a side view which shows the protection tube for molten metal temperature measurement concerning one Embodiment of this invention in a partial cross section. It is the elements on larger scale of the molten metal temperature-measurement protection tube shown in FIG. FIG. 2 is an exploded view of a molten metal thermometer using the molten metal temperature measuring protection tube shown in FIG. 1. It is the elements on larger scale which show the modification of the protection tube for molten metal temperature measurement shown in FIG. It is the elements on larger scale which show the other modification of the protection pipe for molten metal temperature measurement shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Protective tube for molten metal temperature measurement 2 Molten metal thermometer 10 Tube main body 20 Cap 22 Step part 30 Reinforcement material 32 Base material sheet 34 Coating film 40 Temperature detection element

Claims (6)

A temperature measuring protective tube that can accommodate a temperature detecting element for measuring the temperature of the molten metal,
A tube body having openings at both ends, a ceramic cap that closes one end side of the tube body, and a reinforcing material that covers the tube body and the cap ,
The reinforcing material is formed by impregnating a glassy coating material into a base material sheet made of glass fiber and covering the entire surface of the base material sheet with a coating film of the glassy coating material for temperature measurement protection tube. The molten metal temperature measuring protective tube according to claim 1, wherein the base sheet has an inner diameter set smaller than an outer diameter of the pipe body. The said cap is a protective tube for molten metal temperature measurement of Claim 1 or 2 which equips an inner peripheral surface with the step part contact | abutted with the end surface of the said pipe | tube main body. The molten metal temperature measuring protective tube according to any one of claims 1 to 3, wherein the cap is attached to the pipe main body through a flange portion provided on an outer peripheral surface of the pipe main body. The molten metal temperature measuring protective tube according to any one of claims 1 to 4, wherein the cap is made of a silicon carbide material. A molten metal thermometer in which a temperature detection element is accommodated in the molten metal temperature measuring protective tube according to claim 1.

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