JPH06273073A - Detector for collapse of stacked saggers - Google Patents

Abstract

PURPOSE:To effectively prevent collapse of a material to be burned and a saggers and damage of a heater, a gas supply tube due to the collapse of the material to be burned and the saggers by accurately sensing collapse of stacked saggers. CONSTITUTION:A collapse detector for saggers S comprises of load detector 21 for detecting load values of a plurality of load detecting points 22A, 22B, 22C provided separately on a hearth 4 of a heat treating furnace 1, and a load comparator 9 for sensing collapse of the saggers S based on a load value detected by a load detector 21.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stack collapse detection device for detecting a stack collapse of a box loaded on the hearth of a heat treatment furnace.

[0002]

2. Description of the Related Art In order to prevent the collapse of objects to be fired or boxes in a heat treatment furnace and the damage of heaters and gas supply pipes due to these collapses, the heat treatment furnace detects collapsed loading of boxes Equipment is being incorporated.
Conventionally, such a stack collapse detection device is shown in FIG. This stack collapse detection device 50 is provided with a hearth 51
The outer end 52a of the ceramic tube 52 suspended along the outer surface of the box S loaded on the outer casing 52 is pulled out from the upper end of the furnace body 53, and the vibration sensor 54 is attached to the outer end 52a. In the figure, reference numeral 55 is a heater for heating the heat treatment furnace, 56 is a gas supply pipe for supplying an atmospheric gas into the heat treatment furnace, and 51a is a rotary shaft of the hearth 51.

The stack collapse detector 50 is designed to detect a stack collapse by detecting vibrations of the box S when the stack S collapses and comes into contact with the ceramic tube 52 by a vibration sensor 54.

[0004]

By the way, the above-described load collapse detection device 50 has a problem that the load collapse cannot be detected reliably because of poor accuracy. That is, the box S
The ceramic tube 52 interposed between the vibration sensor 54 and the vibration sensor 54 needs to be spaced 10 mm or more from the box S in order to prevent malfunction. This means that the box S has a horizontal direction of 1
If the lateral displacement does not exceed 0 mm, it means that the vibration sensor 53 does not operate. However, when the vibration sensor 53 detects the collapse of the load, the box S may have already collapsed to the point where it cannot be repaired. It was hard to say that the collapse of the stack can be detected with certainty.

Further, instead of directly detecting the collapse of the load, the vibration sensor 54 detects it through the ceramic tube 52, and there is a problem that the accuracy of detection is deteriorated due to the presence of such a ceramic tube 52. It was In order to compensate for the decrease in the detection accuracy, it is conceivable to increase the sensitivity of the vibration sensor 54, but doing so could cause malfunction due to vibrations generated in the heat treatment furnace itself or in the surroundings, and this did not solve the problem.

The present invention addresses such a conventional problem, and accurately detects the collapse of the loading of the box and collapses the object to be fired or the box and the heater and the gas supply pipe accompanying these collapses. The purpose is to reliably prevent damage to the.

[0007]

In order to achieve the above object, the present invention provides a stack collapse detection device for detecting stack collapse of a box loaded on the hearth of a heat treatment furnace, the stack collapse detectors being separated from each other on the furnace floor. And a load comparison unit for detecting a collapse of the box on the basis of the load value detected by the load detection unit. did.

[0008]

According to the above-mentioned structure, when the box is loaded on the hearth,
Since the load of the box is associated with each load detection point, it is detected by the load detection unit. When the box collapses, the load at each load detection point and the load difference between each load detection point change from the initial value. Therefore, if these changes are detected by the load comparison unit, the load collapse can be detected. .

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below with reference to an embodiment shown in FIGS. FIG. 1 is a cross-sectional view of a rotary hearth type heat treatment furnace incorporating a stack collapse detection device according to an embodiment of the present invention, and FIG. 2 is a plan view of a base plate which is a part thereof.

The rotary hearth type heat treatment furnace 1 of this embodiment has a cylindrical furnace body 3 in which a heat treatment chamber 2 having an open bottom is formed.
And a circular hearth 4 that closes the open bottom of the heat treatment chamber 2,
A heater 5 surrounding the hearth 4 and a gas supply pipe 6 for supplying an atmospheric gas into the heat treatment chamber 2 are provided. The hearth 4 can be rotated around its rotation axis 4a by a motor 7,
Further, the elevating mechanism 8 allows the heat treatment chamber 2 to move vertically.
You can move forward and backward. The operation of the heater 5, the motor 7, and the lifting mechanism 8 and the supply of the atmospheric gas are controlled by the control unit 9.

A base plate 10 having a rectangular shape in a plan view is arranged on the hearth 4. That is, a plurality of columns 11 are arranged in the hearth 4 so as to penetrate through the hearth 4 in the vertical direction, and four corners are supported by the upper ends of the columns 11 and the base plate 10 is arranged. A plurality of base plates 10 thus arranged on the hearth 4 are provided along the outer edge of the hearth 4. The boxes S are stacked on the base plate 10 in a plurality of upper and lower stages.

The rotary hearth type heat treatment furnace 1 is equipped with a stack collapse detection device 20. The load collapse detection device 20 includes a load detection unit 21 arranged at the lower ends of three columns 11 out of a total of four columns 11 supporting the base plate 10, and a load of the box S detected by the load detector 21. And a load comparison unit for detecting a collapse of the loading of the box S based on the above. In the present embodiment, the function of the load comparison unit is incorporated in the control unit 9. Further, in the present embodiment, the load detection unit 21 is made of an elastic body (strain gauge) that is elastically deformed by a load.
And a load cell for measuring a load by measuring a change in resistance value of the electric resistor. Further, in the present embodiment, the upper end of each of the columns 11 on which the load detecting unit 21 is arranged has a load detecting point 22.
A, 22B, 22C. Furthermore, the load signal detected by the load detector 21 is transferred to the controller 9 by a wireless mechanism (not shown).

Next, the heat treatment of the objects to be heat-treated and the stack collapse detection operation by the hearth rotary type heat treatment furnace 1 will be described.
First, the hoisting mechanism 8 is driven to lower the hearth 4, and then the box S in which an object to be heat-treated (not shown) is mounted on each base plate 10.
Then, the elevating mechanism 8 is driven again to raise the hearth 4 and the box S is stored in the heat treatment chamber 2. When the housing of the box S is completed, the load at each load detection point 22A, 22B, 22C is detected by the load detection unit 21, and the load signal is transferred to the control unit 9. The control unit 9 that has received the load signal from the load detection unit 21 calculates the load difference between the load detection points 22A-22B and the load difference between the load detection points 22B-22C, and stores them as initial load differences. deep.

When the above preparatory operation is completed, the atmosphere gas is supplied from the gas supply pipe 6, the heater 5 is used for heating (the heating by the heater 5 is carried out as preheating before carrying in the box S), and the motor 7 is used for the hearth 4. Then, the heat treatment operation of the heat treatment object in the box S is started.

During such a heat treatment operation, the control unit 9 fetches the load signal from each load detection unit 21 at regular time intervals, and based on the loaded load signal, between the load detection points 22A-22B at the present time, And load detection point 22B-2
Calculate the load difference between 2C. Furthermore, the calculated load difference at the present time and the initial load difference are compared, and if the difference between the initial value and the current value is within a predetermined value, it is determined that the collapse of the stack has not occurred, and the heat treatment work is performed. continue. On the other hand, if the difference between the initial value and the current value is equal to or greater than the predetermined value, it is determined that the stack collapse has occurred, the heat treatment work is stopped, and the box S
Correct the stacking posture of. That is, when it is determined that the stack collapse has occurred, the heating of the heater 5 is stopped. Then, after naturally cooling the heat treatment chamber 2 to a workable low temperature, the elevating mechanism 8 is driven to lower the hearth 4, and the stacking posture of the boxes S on the hearth 4 is corrected to a normal state.

The load collapse of the box S is thus detected, and the load collapse detecting device 20 detects the load detection point 22.
The load of the box S in A, 22B, and 22C is measured almost directly in the vertical direction, though the support 11 is used. Further, as the load detection unit 21, a load measuring device having a high measurement accuracy, which is a load cell, can be used. Therefore, it is possible to obtain a measurement accuracy within 1%, which is almost three times higher than the conventional one.

Since the load detecting points 22A, 22B and 22C are set at three of the four corners of the base plate 10, even if the box S collapses in any direction of about 360 °, the collapse of the stack can be detected. .

By the way, in the above embodiment, the initial load difference between the load detection points 22A, 22B and 22C calculated based on the load value detected by the load detection unit 21 is compared with the current load difference. However, the present invention is not limited to this, and the initial value of the load value itself and the present time value are compared at each of the load detection points 22A, 22B, 22C, and the difference is a predetermined value. If it is above,
It may be determined that the stack is collapsed.

Further, in the above embodiment, the load detecting unit 2
Although a total of three 1s are provided, the number of the load detection units 21 installed may be more than that, or may be two.

[0020]

As described above, according to the present invention, the load collapse is detected by measuring the change in the load associated with the load collapse of the box, so that the detection accuracy is improved.
Therefore, it is possible to reliably prevent the fired material and the box from collapsing due to the collapse of the box and the damage to the heater and the gas supply pipe due to the collapse.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing the structure of a heat treatment furnace including a stack collapse detection device according to an embodiment of the present invention.

FIG. 2 is a plan view of a base plate which is a part of the embodiment.

FIG. 3 is a vertical cross-sectional view of a heat treatment furnace including a conventional stack collapse detection device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 rotary heat treatment furnace 4 hearth 9 control unit (load comparison unit) 20 stack collapse detection device 21 load detection unit 22A, 22B, 22C load detection point

Claims (1)

[Claims] 1. A stack collapse detection device for detecting a stack collapse of a box (S) loaded on a hearth (4) of a heat treatment furnace (1), which is separated from each other on the hearth (4). Of the load detection points (22A, 22B, 22C) provided on each of the load detection points (22A, 22B, 22C), and a box (S) based on the load values detected by the load detection section (21). ). A stack collapse detection device comprising: a load comparison unit (9) for detecting a stack collapse.