JPH07146182A - Melt temperature measuring instrument - Google Patents

Abstract

PURPOSE:To measure the temperature of a desired depth of a melt by lowering a rod-shaped body to a distance equivalent to a temperature-measurement depth in reference to a position where the change rate of an apparent weight of the rod-shaped body changes. CONSTITUTION:An apparent weight change rate K2 of a molten steel 5 is set to a change rate setting equipment 42 and an insertion depth H is set to a depth setting equipment 51 and a rod-shaped body 8 of a rise edge position 24 is lowered 10 at a low speed. When the lower end face of the rod-shaped body 8 reaches the upper-side interface of a molten slag 6, an apparent weight w of the rod-shaped body 8 decreases by a ratio of K) for an amount of descent y due to the buoyancy. In this case, since the output value of a change rate calculation circuit 41 is equal to a ratio K1 (K1<K2), a comparison circuit 43 does not output an interface detection signal S. When a lower end face reaches an upper side interface 5a, the weight w of the molten steel 5 decreases with a ratio of K2 for the amount of descent y and a circuit 43 outputs a signal S. Then, the amount of descent of the rod-shaped body 8 is measured 6 based on the output y of a position detector 21 and the rod-shaped body 8 stops at that value h=H and then a temperature sensor 31 is retained at a temperature-measurement position R by a temperature-measurement command 62 for measuring the temperature of the molten steel 5.

Description

Detailed Description of the Invention

[0001]

This invention relates to an arc furnace for steelmaking, L
F, an apparatus for measuring a temperature of a desired depth of a molten metal such as an ash melting furnace or a molten slag.

[0002]

2. Description of the Related Art For example, in an arc furnace for steelmaking,
Since the upper surface of the molten steel cannot be observed in the state where the molten steel in the furnace body is covered with the molten slag during the operation of the furnace, the molten steel temperature at the position of the desired depth from the upper surface of the molten steel could not be measured. That is, in general, when measuring the temperature of molten steel, the operator grasps a long rod with a temperature sensor such as a thermocouple at the tip by hand, penetrates the slag layer and immerses it in the molten steel. The bathymetric depth from was inaccurate. There is also a type in which the above-mentioned rod is mechanically moved up and down by an elevation drive device, but since the rod lower end position is constant, the temperature measurement depth also changes when the molten steel level changes, and at the desired temperature measurement depth. Could not be measured.

[0003]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the prior art and aims to provide a melt temperature measuring device capable of measuring the temperature of a desired depth of the melt.

[0004]

A melt temperature measuring device according to the present invention comprises a rod-shaped body extending in the vertical direction, and a temperature measuring device having a temperature sensor attached to the rod-shaped body as a temperature measuring element.
An elevating / lowering device that drives the rod-shaped body up and down to immerse the lower part in the melt, a position detector that detects the vertical position of the rod-shaped body, and a weight detection that detects the apparent weight of the rod-shaped body. And a position signal from the position detector and a weight signal from the weight detector to measure the rate of change of the apparent weight with respect to the amount of vertical movement of the rod-shaped body, and when the value of the rate of change changes, an interface detection signal is output. Interface detection circuit that emits
A depth setter for setting the insertion depth of the rod-shaped body into the temperature measurement target melt layer at the time of temperature measurement, and an upper interface detection signal of the temperature measurement target melt layer detected by the interface detection circuit, And a temperature measurement control circuit that outputs a temperature measurement command signal to the temperature measurement device when the rod-shaped body is lowered by the insertion depth from the time of inputting a signal.

In the present invention, the apparent weight of the rod-shaped body refers to the gravity (actual weight) acting on the rod-shaped body minus the buoyancy acting on the rod-shaped body by immersion in the melt.

[0006]

When the object is immersed in the melt, buoyancy acts on the object and the apparent weight of the object decreases. If this object is a rod-shaped body extending in the vertical direction and having a constant cross-sectional area, the buoyancy is proportional to the immersion depth of the rod-shaped body, and therefore, for example, as shown in FIG. 1 and FIG. As the body is dipped and dipped, the apparent weight w of the rod-shaped body decreases at a constant rate k ₁ with respect to the amount of immersion, and the rod-shaped body is formed in the melt 5 on the lower layer side beyond the lower interface. When descending and soaking,
The apparent weight w decreases with another ratio k ₂ (k ₂ > k _{1 because the} specific gravity of the melt on the lower layer side is naturally high).

According to the present invention, as described above, the apparent weight of the rod-shaped body changes at the inflection point (points P ₁ and P in FIG.
_In the present invention, the rate of change in the apparent weight of the rod-shaped body is measured and the position where the value of this rate of change changes is detected. Since this position corresponds to the inflection point, the rod-shaped body is further lowered by a distance corresponding to the temperature-measuring depth with reference to this position, and the temperature is measured by the temperature sensor attached to the rod-shaped body.

That is, in the melt temperature measuring apparatus of the present invention, when the rod-shaped body is driven downward by the elevating / lowering device, the interface detection circuit is rod-shaped based on the position signal of the position detector and the weight signal of the weight detector. An interface detection signal is output when the apparent weight value of the body changes, and the temperature measuring controller receives the upper interface detection signal of the melt layer to be measured, and then the rod shape is inserted by the depth setter. When the body descends, a temperature measurement command signal is issued, and the temperature measuring device receiving the signal measures the temperature of the desired depth of the melt.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIGS. In the figure, 1 is an arc furnace for steelmaking, 2 is a furnace body, 3 is a furnace lid, and scraps charged into the furnace body 2 from a charging port (not shown) are melted by the arc heat of the electrode 4 to melt steel (melting steel). No. 5), the temperature of the molten steel 5 is adjusted, and refining is performed by adding an additive material. 6 is a molten slag (molten material) formed on the upper side of the molten steel 5.

Reference numeral 8 denotes a rod-shaped body extending in the up-down direction that can be inserted into and removed from the furnace through a hole 3a formed in the center of the furnace lid 3. In this embodiment, a round bar-shaped refractory having a constant horizontal sectional area is used. There is.
Reference numeral 10 denotes an elevating and lowering drive device for vertically moving the rod-shaped body 8, which connects one end of the wire rope 13 wound around the deflecting wheels 11 and 12 axially supported by a frame (not shown) to the upper end of the rod-shaped body 8.
The other end is wound around a winding drum 15 which is driven to rotate by an electric motor 14. Reference numeral 16 is an operation control device of the electric motor 14.

A position detector 21 is composed of a pulse generator connected to the rotary shaft of the electric motor 14, and detects the vertical position of the rod 8 by the rotation angle of the winding drum 15 to generate a position signal y. Reference numeral 22 denotes a weight detector having a piezoelectric element as a detection element. The weight detector 22 detects the apparent weight of the rod-shaped body 8 which is changed by buoyant force when immersed in the molten slag 6 or the molten steel 5 below the rod-shaped body 8. Is detected as the tension of the weight signal w and the weight signal w is emitted. In this embodiment, the vertical position of the rod 8 is represented by the amount of descent from the reference position 25 which is the lower end face position of the rod 8 at the rising end position 24 shown by the chain line.

On the other hand, 31 is a temperature sensor comprising a protective tube type thermocouple attached to the lower end surface of the rod-shaped body 8, 32 is a thermometer output from the temperature sensor 31 converted from a millivolt meter to a temperature scale, and a measured temperature T is obtained. An output converter, 33 is a display (CRT) for displaying the measured temperature, and 34 is a printer for printing and recording the measured temperature, and the temperature measuring device 30 is constituted by these devices.

Reference numeral 40 denotes an interface detection circuit, which is a sampling time interval of a predetermined short time (for example, 0.1 seconds) tuned to a clock pulse, and changes the apparent weight change value Δw during the time interval of the rod-shaped body 8. A rate-of-change calculation circuit 41 that outputs an apparent rate of change in weight Δw / Δy by dividing by the amount of elevation Δy;
The apparent weight change rates k ₁ (within the molten slag 6 layers) and k ₂ (molten steel 5) corresponding to the increase rate of the buoyancy acting by entering the molten slag 6 layer and molten steel 5 layer below the rod-shaped body 8.
Change rate setting device 42 for setting any of (in the layer) according to the temperature measurement target melt layer, and the change rate Δw / Δy is k
_The interface detection signal S becomes equal to ₁ or k _2.
And a comparison circuit 43 for outputting

As shown in FIG. 2, the rate of change k ₁ and k ₂ is such that the rod 8 is lowered and the lower portion thereof is melted by the molten slag 6.
And the immersion weight of the molten steel 5, the apparent weight w of the rod 8 changes with respect to the descending amount y due to the buoyancy generated by the removal of these melts, and k ₁ is the ratio of the molten slag 6. To the value obtained by multiplying the weight by the cross-sectional area of the rod-shaped body 8,
k ₂ is equal to the value obtained by multiplying the specific weight of the molten steel 5 by the cross-sectional area of the rod-shaped body 8. The k ₁ and k ₂ used in the rate-of-change setting device 42 may be calculated by the above calculation based on actual measured values of specific weights, etc., but the rod-shaped body 8 is driven to descend and immersed in the molten slag 6 and the molten steel 5. It is preferable to use k ₁ and k ₂ obtained by performing a test run.

Reference numeral 51 sets the insertion depth H of the rod-shaped body 8 into the temperature-measured melt layer during temperature measurement (the distance from the upper interface of the temperature-measured melt layer to the lower end surface of the rod-shaped body 8). It is a depth setting device for. In this embodiment, the temperature sensor 3
Since 1 is attached to the lower end surface of the rod-shaped body 8, the insertion depth is equal to the temperature measurement depth. Reference numeral 60 denotes a temperature measurement control circuit, which outputs a stop command signal P ₁ to the operation control device 16 of the electric motor 14 when the lower end surface of the rod-shaped body 8 descends from the upper interface to the position of the insertion depth H, and The temperature measurement command signal P ₂ is output to the converter 32 of the measuring device 30, and the rod-shaped body 8 from the time when the interface detection signal S of the interface detection circuit 40 is input.
A descent amount measuring circuit 61 that measures the moving (falling) distance of the position detector 21 by counting the output pulses of the position detector 21, and the descent amount output value h of the circuit and the depth setting value H of the depth setting device 51 are compared. Then, when the two values become equal, the respective command signals P ₁ , P
_And a comparison circuit 62 for outputting ₂ .

The temperature of the molten steel at the temperature measuring position R of the depth H of the molten steel 5 is measured by the temperature measuring device 70 having the above-described structure as follows. First, the rate of change setter 42 is set to the rate of change k ₂ in apparent weight of the molten steel 5 as the temperature measurement target melt layer, and the depth setter 51 is set to the insertion depth H. Then, the rod-shaped body 8 at the rising end position 24 is driven to descend by the lifting drive device 10 at a low speed (for example, 10 cm / sec). While the lower end surface 8a of the rod-shaped body 8 is descending in the air, since the apparent weight w of the rod-shaped body 8 is constant equal to its own weight w ₀ , Δw / Δy is almost 0 (depending on the accuracy of each detector and the wire rope weight, etc.). Strictly not 0),
The interface detection circuit 40 does not generate an output.

When the lower end surface 8a of the rod-shaped body 8 reaches the upper interface (position y ₁ ) of the molten slag 6 layer, the buoyancy of the molten slag 6 begins to act upward, so that the apparent weight w with respect to the descending amount y. including reduction at a constant rate k _1, the change rate calculating circuit output value of 41 is substantially equal to k ₁ (k ₁ is strictly due accuracy or wire rope weight of the detectors
However, since this output value is smaller than the set value k ₂ of the change rate setter, the comparison circuit 43 does not output the interface detection signal.

When the rod-shaped body 8 continues to descend and its lower end surface 8a reaches the upper interface 5a of the molten steel 5 (= the lower interface of the molten slag 6, the position y ₂ ), buoyancy by the molten steel 5 begins to be exerted,
The apparent weight w is a constant ratio k ₂ (>
Since the decrease starts at k ₁ ), the output value of the change rate calculation circuit 41 becomes substantially equal to k ₂ , so the comparison circuit 43 outputs the interface detection signal S. As a result, the descending amount measuring circuit 6
1 measures the descending amount of the rod-shaped body 8 based on the output y of the position detector 22, and the descending amount output value h is the set value H of the depth setter 51.
When it becomes equal to, the comparison circuit 62 determines that the stop command signal P
₁ and temperature measurement command signal P ₂ are output.

As a result, the electric motor 14 is stopped for a predetermined short time (for example, 10 seconds), the temperature sensor 31 at the tip of the rod 8 is held at the temperature measuring position R, the temperature of the molten steel 5 is measured, and the measured temperature T is , Displayed on the display 33, and printed and recorded by the printer 34. Since the temperature measurement is completed as described above, the electric motor 14 may be moved upward to drive the rod-shaped body 8 upward and pulled out of the furnace.

As described above, the temperature of molten steel at a desired depth from the upper interface of the molten steel 5 which cannot be monitored and fluctuates up and down is easily and accurately measured without requiring troublesome manual work. can do. With this, it is possible to accurately know whether the heating amount of the molten steel 5 is excessive or insufficient,
It is possible to improve the thermal efficiency of the arc furnace 1 by appropriately controlling the amount of bubbling and stopping the energization of the electrodes.

The measured temperature T may be output to a device other than the display 33 and the printer 34, such as a computer for operating the arc furnace 1. When the slag temperature at the position of the desired depth of the molten slag 6 is measured by the temperature measuring device 70, the rate of change k ₁ may be set in the rate of change setter 42.

The present invention is not limited to the above-described embodiments. For example, the material and cross-sectional shape of the rod-shaped body may be other than those described above, and the interface detection circuit may have the apparent weight of the rod-shaped body. A circuit configuration other than the circuit of the above embodiment for comparing the change rate Δw / Δy and the set value by the change rate setting device may be provided. Further, the temperature measurement control circuit also subtracts the position (y _{2 in the} above embodiment) at the time of inputting the interface detection signal from the descending amount y of the rod 8 from the reference position 25 and the set value H of the depth setter. Other than the above embodiments, such as those having a circuit configuration for comparison, may be used.

In the above embodiment, the temperature was measured at one measurement position in the molten steel 5. However, a plurality of insertion depths are set by the depth setting device 51, and the temperature is sequentially measured at a plurality of temperature measurement depth positions. You may make it measure temperature. Further, in the above embodiment, the temperature sensor 31 is provided at the lower end surface position of the rod-shaped body 8 (offset amount = 0 described later), but as shown in FIG. 3, the temperature sensor 31 attached to the rod-shaped body 8 via the holder 81.
When the vertical position of is shifted upward (or downward) by the offset amount L with respect to the lower end surface 8a of the rod-shaped body 8, the value of the insertion depth H of the depth setting device 5 is the temperature measurement depth. The value may be a value obtained by adding the above offset amount L to H ₀ (subtracting when it is below the lower end surface 8a). Reference numeral 82 in the figure is a protective material made of a heat resistant material.

Further, the elevating / lowering device 10 is, for example, as shown in FIG.
As shown in, a guide roller 9 is attached to a frame (not shown).
A long metal rod 9 supported by 1 so as to be able to move up and down.
The rod-shaped body 8 is fixed to the lower end of the connector 2 via the connector 93, and the rod 92 is connected to the chain 96 wound around the sprockets 94 and 95, so that the sprocket 95 is driven by the electric motor 97.
It may be configured to be driven by. 22 is an electric motor 9
7 is a weight detector composed of a torque sensor interposed between the output shaft of 7 and the sprocket 95, and 21 is a position detector composed of a pulse generator similar to the above-mentioned embodiment.

The rod-shaped body 8 in FIG. 4 is a round rod-shaped molded body in which a metal tube holder 98 having a temperature sensor 31 attached to the lower end is surrounded by a refractory material 99 as a protective material. Similarly to the case of FIG. 3, the offset amount L with respect to the lower end surface 8a of the temperature sensor 31 is set to the temperature measurement depth H.
_{The value} of the insertion depth H of the depth setter 5 may be set by adding to ₀ .

In the above embodiment, the temperature measuring control circuit 8 outputs the stop command signal P ₁ to temporarily stop the rod-shaped body 8. However, when a temperature sensor having a high temperature measuring sensitivity is used, It is also possible to continue descending toward the next lower temperature measuring position without outputting the stop command signal, or to immediately reverse and raise the rod-shaped body 8.

The present invention can also be applied to an apparatus for measuring the temperature of a desired depth position of an arbitrary layer of a melt composed of one layer or three or more layers.

[0028]

As described above, according to the present invention,
It is possible to measure the temperature of the melt at a desired depth position, and particularly to easily and easily measure the temperature at the desired depth of the lower melt layer of the plurality of melt layers in a laminated state which has been difficult in the past. Can be measured accurately.

[Brief description of drawings]

FIG. 1 is a device system diagram of a temperature measuring device showing an embodiment of the present invention.

FIG. 2 is a diagram showing the relationship between the apparent weight of a rod-shaped body and the vertical position in the apparatus of FIG.

FIG. 3 is a schematic front view (partially cutaway) of a rod-shaped portion showing another embodiment of the structure for mounting the temperature sensor on the rod-shaped body in the apparatus of FIG.

FIG. 4 is a schematic front view (partially cutaway) of a lifting drive device and a rod-shaped body showing another embodiment of the lifting drive device and the rod-shaped body in the apparatus of FIG.

[Explanation of symbols]

5 ... Molten steel (melt), 5a ... Upper interface, 6 ... Molten slag (melt), 8 ... Rod-shaped body, 10 ... Lift drive device, 13 ...
Wire rope, 14 ... Electric motor, 21 ... Position detector, 22
... weight detector, 30 ... temperature measuring device, 31 ... temperature sensor, 40 ... interface detecting circuit, 51 ... depth setting device, 60 ... temperature measuring control circuit, 70 ... temperature measuring device, 92 ... rod, 96
… Chains, 97… motors.

Claims (1)

[Claims] 1. A vertically extending rod-shaped body, a temperature measuring device having a temperature sensor attached to the rod-shaped body as a temperature measuring element, and the rod-shaped body being driven up and down to immerse the lower portion in the melt. An elevating and lowering drive device, a position detector that detects the vertical position of the rod-shaped body, a weight detector that detects the apparent weight of the rod-shaped body, a position signal from the position detector, and a weight from the weight detector. An interface detection circuit that receives a signal to measure the rate of change of the apparent weight with respect to the amount of vertical movement of the rod and issues an interface detection signal when the value of the rate of change changes, and a temperature measurement target of the rod during temperature measurement. A depth setter for setting the insertion depth into the melt layer, and an upper interface detection signal of the melt layer to be temperature-measured by the interface detection circuit, which receives the signal from the time when the signal is input and the insertion depth is equal to the depth. When the rod is lowered, the temperature A temperature measuring control circuit for outputting a temperature measuring command signal to the temperature measuring device, the melt temperature measuring device.