JPH0310049B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a detection tool that is attached to a continuous casting mold and used to detect the level of molten metal within the mold.

In the continuous casting method, it is necessary to maintain the amount of molten steel in the mold within a certain range, so in order to ascertain the level of molten steel, thermocouples are used to measure the temperature of each part of the mold, and then the molten steel level is determined. γ
Although there are radiation transmission methods, methods using electromagnetic coils and gamma rays require a lot of attached equipment, are inconvenient in terms of the working environment, and have an adverse effect on the human body, so methods using thermocouples are preferred and most commonly adopted.

However, currently used thermocouple methods for detecting molten steel levels include, for example, a method in which many thermocouples 2' are inserted into the outer wall of a mold body 1' as shown in Fig. A vertical hole 3' is opened in the mold body from the upper end surface of the body 1', and a side temperature terminal 5' having a large number of temperature sensing pins 4' as shown in FIG. 3 is arranged in the vertical hole, etc. Since the thermocouple is inserted into the mold body 1' itself, the mold body and the side temperature point must be quite far apart, resulting in poor side temperature accuracy and response. Each time a modification was made, the distance from the side temperature point to the surface of the mold body changed, and the measured value had to be calibrated each time.

The present invention aims to provide a molten metal level detection device that eliminates the above-mentioned drawbacks, and its gist is to provide a molten metal level detection device that is insulated around the periphery of a copper or copper alloy flat plate that constitutes a continuous casting mold. A plurality of signal wires are buried so that their tips face the side end surface of the plate that contacts the molten steel, and their base ends protrude from the other side end surface or top end surface of the plate, and the signal wire tips of the plate are buried. A heat-resistant and wear-resistant surface layer made of a material different from that of the plate body is installed on the side end surface where the surface layer is located and the tips of the signal wires are electrically connected, and the inside of the signal wires protruding outside the plate body is attached. A device for detecting the level of molten steel in a mold for continuous casting, characterized in that one of the signal wires is connected to another signal wire to form a closed circuit, and a potentiometer is placed in each of these closed circuits. In some cases, the material of the surface layer is the same as that of the surface layer.

Note that the surface layer may be a single layer or a multilayer, and when the material of the signal line is the same as that of the surface layer, it shall be the same as the bottom surface layer.

The molten steel level detector of the present invention is shown in Figs. 4 to 9 below.
To explain in detail with reference to the drawings, as shown in FIG. 4 or 5, there are a plurality of signal wires 2 whose peripheries are insulated in a flat plate 1 made of copper or copper alloy. It is built in so as to face one side end surface of the flat plate body 1. A heat-resistant and wear-resistant surface layer 3 made of nickel or nickel alloy is usually attached to the side end surface of the flat plate body 1 on the side where the tip of the signal wire 2 is located, and the surface layer 3 and the signal wire 2 and are electrically connected only at the tip of the signal line.

When such a molten steel level detector is actually used, it is attached to both sides of the short-side mold 4 and held between the long-side molds 5 and 5, as shown in FIGS. 6 and 7, for example. In this case, as shown in the figure, the molten steel level detector is mounted so that its surface layer 3 faces toward the inner surface of the mold, ie, the space through which the molten steel is to pass. For actual installation, it is most desirable to use a method in which a back frame (not shown) is provided behind the mold side and the mold is fixed to the back frame.
In that case, considering the convenience of drawing out the signal line 2 and connecting it to the instrument afterwards, the base end of the signal line 2 should be the fifth
As shown in the figure, the configuration that protrudes from the upper end surface of the flat plate body 1 is more preferable than the configuration shown in FIG.

When the molten steel level detector of the present invention is incorporated into a continuous casting mold as described above, the interface between the flat plate body 1 and the surface layer 3 attached to one end surface of the plate body 1 has the thermoelectric potential of both materials. There is a thermoelectromotive force determined only by the difference between It is determined by the temperature on the surface layer 3. Therefore, as shown in FIG. (preferably one taken out from a place) or a plurality of each between the conductor 2S drawn out from a part of the mold or back frame where the temperature change is as small as possible and the plurality of signal wires 2a, 2b, 2c...2g. Closed circuit 2S-2a, 2S-2b, 2S-2c
...2S-2g, and by arranging a potentiometer in each circuit and measuring the potential difference generated in each circuit, each signal line 2a, 2b, 2
c... Flat plate body 1 at the part where the tip of 2g is arranged
The thermoelectromotive force generated at the interface between the surface layer 3 and the surface layer 3 can be measured. Next, use this method to generate thermoelectromotive force (potential difference)
This section explains how to measure and detect the molten steel level.

As mentioned above, there are multiple signal lines 2 in the vertical direction of the mold.
A, 2b, 2c...2g are arranged to form a closed circuit with the conducting wire 2S, and the potential difference Ei that occurs between the signal wire and the conducting wire is such that the distance from the top layer of the mold is Yi. Since a plurality of signal lines are provided, a plurality of Yi can be selected, so the Ei obtained for each type of Yi is obtained, and a graph as shown in FIG. 9 is obtained.
From the graph shown in Figure 9, the maximum potential difference Em
The molten steel level surface at that point is determined by finding the position Ym that indicates Ym and adding a constant value H (which can be measured in advance) determined by the size and shape of the mold to Ym.

As described above, according to the present invention, since the measurement point is very close to the molten steel, the obtained values are accurate and the response is quick. In addition, since it is used by being incorporated into a mold, even if an accident such as a signal wire breakage occurs, it is easy to deal with it because only a partial replacement is required without replacing the entire mold.

Furthermore, when a continuous casting mold is used with the short side mold 4 sandwiched between the long side molds 5, 5, as shown in FIG. 6, the short side mold 4 causes width contraction and the short side mold 4 A gap is created at the joint between the long-side mold 5 and the long-side mold 5, so if the gap becomes large enough, the surface of the short-side mold 4 must be repaired. If the tool is assembled in advance and only that part is replaced when shrinkage occurs, there will be very little modification to the surface of the short side mold 4, and the life of the mold can be extended accordingly. It is. This problem of width shrinkage of the short side mold 4 is caused by heat and is particularly noticeable in the meniscus area, so it is also possible to incorporate the molten steel level detector of the present invention only in the meniscus area or only above the meniscus area. .

In addition, in the molten steel level detection device of the present invention, if the material of the signal wire is the same as that of the surface layer, when extracting the thermoelectromotive force existing at the interface between the surface layer and the flat plate, the signal wire itself Since this method does not constitute any thermocouple and merely functions to transmit the thermoelectromotive force at the interface to the outside, rapid measurement is possible regardless of the wire diameter of the signal wire.

[Brief explanation of the drawing]

Figures 1 and 2 are explanatory diagrams showing the conventional molten steel level detection method, Figure 3 is the same temperature measuring terminal, Figures 4 and 5 are explanatory diagrams of the molten steel level detector of the present invention, respectively, and Figure 6 is an explanatory diagram showing the conventional molten steel level detection method. 7 and 7 are explanatory diagrams showing the same usage state, FIG. 8 is an explanatory diagram showing the same molten steel level detection method, and FIG. 9 is a graph explaining the same molten steel level detection method.

Claims (1)

[Scope of Claims] 1. A plurality of signal wires whose peripheries are insulated are arranged in a flat plate made of copper or copper alloy constituting a mold for continuous casting, and the side end surface of the plate whose tips are in contact with the molten steel of the plate is provided. The proximal end is buried so as to protrude from the other side end surface or upper end surface of the plate, and a heat-resistant,
A closed circuit in which a wear-resistant surface layer is attached so that the surface layer and the tips of the signal wires are electrically conductive, and one of the signal wires protruding outside the board is connected to the other signal wires. A device for detecting the level of molten steel in a mold for continuous casting, characterized in that a potentiometer is arranged in each of these closed circuits. 2. The molten steel level detector in a continuous casting mold according to claim 1, wherein the signal line is made of the same material as the surface layer.