JPH0135596Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a duct that serves as a transfer path when molten metal (hereinafter referred to as "molten metal") is transferred.

In metallurgy, casting, and other fields that handle molten metal, electromagnetic pumps are used as means for transporting the molten metal. This electromagnetic pump for molten metal has a structure as shown in FIG. 1, and consists of a duct 1 for introducing molten metal and a stator 2 disposed on the outer circumferential side of the duct 1. A coil 3 (primary winding) is wound around the stator 2. For example, if three coils are arranged offset in the longitudinal direction of the duct 1 and a three-phase alternating current is applied thereto, a rotating magnetic field will be generated in the duct 1. occurs. When molten metal is introduced into the duct 1, it acts as a secondary conductor and receives thrust in the longitudinal direction of the duct 1 under the action of the rotating magnetic field, and is transported in the same direction. This duct 1
A heater 5 is wrapped around the outer periphery of the metal, and preheats the molten metal therein so that it does not cool and solidify.

By the way, the molten metal transferred through duct 1, taking aluminum as an example, has a melting point of 660.
.degree. C., it has a higher temperature in the molten state, and the heater 5 that preheats the duct 1 from the outside also requires a heating temperature approximately close to this temperature. In addition to being exposed to such high temperatures, the duct 1 is also constantly susceptible to corrosion by molten metal. Therefore, metal materials cannot be used for the duct 1, and ceramic materials such as pottery are used exclusively, and in addition, the thickness of the duct 1 has a large effect on the magnetic field generated inside.
Do not make it larger than necessary. For this reason, the duct 1 is inevitably fragile and mechanically extremely weak.

For these reasons, relatively many accidents occur in electromagnetic pumps for molten metal, such as breakage of the duct 1 during operation, and this is considered to be the biggest problem with conventional ducts for transporting molten metal. Especially if duct 1 is damaged during molten metal transfer,
Molten metal leaks out of the duct 1 and flows into the stator 2, preheater 5, and other parts of the electromagnetic pump, causing a short circuit in the electric circuit, corrosion of metal parts, and even a fire hazard. Further, the molten metal flowing out of the duct 1 cools and solidifies in the air, and therefore adheres to various places, making it extremely difficult to remove.

This invention was made to solve the above-mentioned conventional problems with molten metal transfer ducts. By using special coating means, the thermal and mechanical weaknesses of each member can be reduced. The two elements complement each other to provide high strength and the ability to hold molten metal as a whole.This prevents accidents such as those mentioned above, and even if a breakage accident occurs, it can be prevented from occurring. The aim is to minimize the damage caused.

That is, in the present invention, in order to achieve the above object, in a molten metal transfer duct that introduces molten metal into a duct 1 made of a ceramic material and transfers it along the duct 1, the duct 1 A molten metal leak detector 6 is inserted between the duct 1 and the seal material 4 to detect leakage of molten metal. Metal coating on the outer periphery 5
The metal coating 5 is tightened in the hoop direction of the duct 1, and a preheater 7 is placed around the outer periphery of the metal coating 5.
A duct for transporting molten metal is provided in which the heater 7 is covered with a heat insulating material 8, and the heat insulating material 8 is covered with a metal tube 9.

In this case, the sealing material 4 is suitably made of mica.

Hereinafter, the configuration of this invention will be explained in detail based on illustrated embodiments.

As shown in FIGS. 1 and 2, the molten metal transfer duct according to this invention covers the outer periphery of the duct 1 with a sealing material 4 having a certain degree of flexibility and heat resistance.
Further, the outside thereof is covered with a metal coating 5, and this metal coating 5 is tightened in the direction of the hoop to apply stress. As the sealing material 4, it is preferable to wrap a mica sheet or other sheet-like heat-resistant and corrosion-resistant material around the duct 1, and it is particularly desirable to use a material with high insulation properties in view of the relationship with the molten metal leak detector described later. A material such as stainless steel is used for the metal coating 5. For example, a thin plate of stainless steel is wrapped in a tubular shape over the sealing material 4, and this is tightened and welded and fixed while applying stress in the hoop direction.

Further, a molten metal leak detector 6 is inserted between the duct 1 and the sealing material 4. The molten metal leak detector 6 of the illustrated embodiment has two conductors attached to the outer peripheral surface of the duct 1 in a mutually insulated state. Since the two conductors are short-circuited, a leakage state can be detected by electrically detecting this. In the case of Fig. 1, two conductors are attached in parallel to the longitudinal direction of the duct 1, and in the case of Fig. 2, they are wound spirally around the outer circumference of the duct 1 with a substantially constant interval. There is.

The embodiment shown in FIG. 1 shows a state in which the duct for transporting molten metal is applied to a part constituting an electromagnetic pump, and a preheater 7 is wrapped around the outer periphery of the metal coating 5. It is covered with a heat insulating material 8 having high heat insulation properties and heat resistance. Further, this heat insulating material is covered with a metal tube 9, and the stator 2 is formed on the outside of the metal tube 9. On the other hand, the embodiment shown in FIG. 2 is applied to a part that does not constitute an electromagnetic pump, a part that simply functions as a transfer path for molten metal, and in many cases the outer periphery of the metal coating 5 is Similarly, a preheater 7 is wrapped around the molten metal to prevent cooling of the molten metal.

In the molten metal transport duct according to this invention, the sealing material 4 and the metal coating 5 function as follows. First, the outer metal coating 5 protects the duct 1 from external impacts, etc., and also tightens the duct 1 due to the stress applied during installation, making the duct 1 mechanically brittle and lacking in tensile strength in the hoop direction. Supplements the strength of the objective. Therefore, the duct 1 becomes difficult to break and at the same time, even if some cracks or cracks develop, these cracks are prevented from further expanding due to the above-mentioned stress. Next, since the sealing material 4 has a certain degree of flexibility, it is tightened by the outer metal coating 5 and tightly adheres to the surface of the duct 1, absorbing external shocks and the like, and also absorbs some degree of stress. Even if cracks or holes appear, they are sealed to prevent molten metal from leaking.

As described above, in the molten metal transfer duct of this invention, the thermal and mechanical weaknesses of each member are mutually complemented, and high strength and molten metal holding function are obtained as a whole. . Therefore, the duct 1 becomes difficult to break, and even if a crack or crack occurs, the molten metal inside will not leak out immediately, thus preventing various troubles caused by leakage. can be kept to a minimum.

[Brief explanation of drawings]

The drawings all show examples of this invention. Fig. 1 is a partially peeled perspective half-sectional view showing the application of this invention to an electromagnetic pump for molten metal, and Fig. 2 is a partially peeled perspective view. , is a partially peeled perspective half-sectional view showing a state in which this invention is applied to parts other than the electromagnetic pump. 1...Duct, 4...Sealing material, 5...Metal coating.

Claims (1)

[Claims for Utility Model Registration] 1. A molten metal transport duct that introduces molten metal into a duct 1 made of ceramic material and transports it along the duct 1,
The outer periphery of the duct 1 is covered with a flexible and heat-resistant sealing material 4, and a molten metal leak detector 6 for detecting leakage of molten metal is inserted between the duct 1 and the sealing material 4. A metal coating 5 is placed on the outer periphery of the duct 1, and the metal coating 5 is tightened toward the hoop of the duct 1.
A molten metal transport duct characterized in that a preheater 7 is wound around the outer circumference of the duct, the heater 7 is covered with a heat insulating material 8, and the heat insulating material 8 is covered with a metal tube 9. 2. The duct for transferring molten metal according to claim 1, wherein the sealing material 4 is made of mica.