JPH0792338B2 - Tunnel furnace pusher drive - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pusher drive device for a tunnel furnace used for continuously pushing a trolley or a plate on which a product to be fired is placed into a furnace by a hydraulic pusher.

[0002]

2. Description of the Related Art In a pusher type tunnel furnace, firing is carried out while a truck or a base plate is continuously pushed into the furnace by a hydraulic pusher provided on the inlet side of the furnace.
In this case, since the pushing speed of the pusher directly becomes the conveying speed of the bed plate or the like in the furnace, the speed control of the pusher is performed by the flow control valve of the hydraulic circuit. However, speed control by such a flow control valve is apt to change speed due to fluctuations in oil temperature and deterioration of oil, especially when trying to push at a low speed, it is necessary to extremely reduce the oil flow rate. Is likely to occur.
For this reason, the transfer speed of the product to be fired in the furnace changes,
In some cases, overburning or underburning may occur and desired characteristics may not be secured.

Therefore, measures have been taken to stabilize the oil flow rate by attaching a cooler and a heater to the oil tank to stabilize the oil temperature, or by using a flow control valve with an oil temperature and oil pressure correction function. However, in the former method, the equipment cost is high and it is necessary to always flow the cooling water. Further, the latter method has a drawback that it can cope with changes in oil temperature and oil pressure, but cannot deal with changes in viscosity due to deterioration of oil.

[0004]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the prior art and allows the pushing speed of a hydraulic pusher to fall in a low speed range without being affected by a change in oil temperature or a change in oil viscosity. The purpose of the present invention is to provide a pusher drive device for a tunnel furnace that can be accurately controlled by.

[0005]

The first invention made to solve the above-mentioned problems is to integrally attach a linear scale plate having scales of equal pitch to a hydraulically driven pusher, and at the same time, to the furnace body side. A scale detecting means for sending a signal to the hydraulic circuit each time the scale is detected, and a predetermined dividing
Equipped with a timer that activates the pusher every cycle time
Well, when the pusher receives the signal from the scale detection means,
The present invention is characterized in that a feed speed control means for stopping is provided. It was also done to solve the same problem
The second invention is that a hydraulically driven pusher has an equal pitch.
If you attach the linear scale plate with the scale of
On the other hand, the furnace side has a hydraulic circuit every time the scale above is detected.
Flow connected in parallel with the scale detection means that sends a signal
The control valve responds to the signal from the scale detection means.
And a feed speed control means for opening and closing
It is something.

[0006]

The present invention will be described in more detail below with reference to the embodiments shown in the drawings. Fig. 1 shows the whole tunnel furnace.
Is a furnace body, 2 is a base plate on which the product to be fired 3 is placed, and a large hydraulically driven pusher 4 provided at the inlet of the furnace body 1 moves the base plates 2 one at a time into the furnace body 1 at low speed By pushing in, all the base plates 2 are moved toward the outlet to perform firing. In this embodiment, the size of the base plate 2 in the traveling direction is 32.
It is 0 mm, and the base plate 2 is pushed in by 320 mm in 160 seconds.

Although the pusher 4 is of a hydraulic drive type, it is not easy to control the pushing speed at the low speed as described above. Therefore, in the present invention, the linear scale plate 6 is integrally attached to the pusher head 5 of the pusher 4, and the speed is controlled by utilizing this. The linear scale plate 6 is a plate on which scales 7 of equal pitch are formed as shown in FIG. 2, and the lengths of the scale plates at both ends thereof are equal to the length of the base plate 2, and in the embodiment, 320 mm is set. It is divided into 16 parts every 20 mm.

On the other hand, a scale detecting means 8 for detecting the scale 7 is provided in the furnace body. In this embodiment, the scale is 7
Is a through hole formed in the linear scale plate 6 and is a scale detecting means 8
Is a photoelectric tube, but any other scale detecting means 8 such as a proximity switch or a limit switch can be used, and the scale 7 can also use any scale corresponding thereto.

As shown in FIG. 2, the hydraulic circuit according to the first embodiment of the invention includes a pump 9, a switching solenoid valve 10 for switching the direction of the pusher 4, a flow control valve 11, and an electromagnetic valve for fast-forwarding. When the solenoid valve 12 is in the position shown in FIG. 2, the pusher 4 is stopped. However, when the solenoid valve 12 receives a signal from the timer 13 connected thereto, hydraulic pressure is introduced into the rear end of the pusher 4 and the pusher 4 moves in the direction of the arrow.

The timer 13 divides the cycle time (160 seconds in the embodiment) of the operation of the pusher 4 by the number of intervals (16) of the scale 7 and divides the cycle time (160 seconds / 16 = 10 seconds). Solenoid valve for hydraulic circuit 1
2 sends a signal to start pusher 4. At the same time, it resets itself and starts counting the divided cycle time again. On the other hand, the solenoid valve 12 receives a stop signal every time the scale detecting means 8 detects the scale 7 and stops the pusher 4.

The operation of the device of the first invention thus constructed is as follows. First, when the pusher 4 starts up, the timer 13 starts counting time at the same time, but since the hydraulic circuit supplies the hydraulic pressure to the pusher 4 without extremely reducing the oil flow rate, the pusher 4 moves at a relatively high speed. However, a linear scale plate 6 is integrally attached to the pusher 4, and the linear scale plate 6 also moves together with the pusher 4. And the scale 7 next to the starting position
Is detected by the scale detecting means 8, a stop signal is sent to the solenoid valve 12, and the pusher 4 stops at the position moved by one scale (20 mm). This stopped state continues until the divided cycle time (10 seconds) elapses, but when the divided cycle time elapses, the timer 13 restarts the solenoid valve 1.
2, the pusher 4 is moved, and the pusher 4 advances 20 mm to the position where the next scale 7 is detected by the scale detecting means 8.

In this way, according to the present invention, the pusher 4 can be accurately moved by one scale (20 mm) for each divided cycle time (10 seconds). And 1
When the pusher 4 moves up to 6 scales (320 mm), the pushing of one base plate is completed. At the same time, one base plate 2 is pushed out from the outlet side of the furnace body 1, and this is detected by the limit switch 14 at the furnace body outlet, and the switching solenoid valve 10 of the hydraulic circuit is switched to set the pusher 4 to the final position. The same operation is repeated thereafter.

As described above, the feed rate control means can accurately move the pusher 4 by one scale for each divided cycle time, and as a whole, accurately moves the pusher 4 by a predetermined distance during a predetermined cycle time. be able to. Moreover, the stop position for each divided cycle time can be set with extremely high accuracy by the scale 7 and the scale detecting means 8, and the operation of the pusher 4 between the scales 7 can be lowered by the flow control valve as in the conventional case. Since it is not necessary to control the speed, it is possible to always perform stable operation without being affected by changes in oil temperature and oil pressure.

FIG. 3 shows an embodiment of the second invention .
The pump 9 and the switching solenoid valve 10 for switching the direction of the pusher 4 are the same as in the first embodiment of the invention, but instead of the timer 13, three flow control valves 14, 15, 16 are provided. It is provided. These flow control valves are connected in parallel, and the flow control valve 14 is always open, but the flow control valves 15 and 16 can be opened / closed according to a signal from the scale detecting means 8. . Reference numeral 17 is a hydraulic circuit for moving the pusher 4 forward and backward at high speed, but the description thereof is omitted because it is not directly related to the present invention.

The operation of the feed rate control means of the second invention is as follows. That is, the graduation detecting means 8 detects the movement of the pusher 4 for each graduation and compares the time t required to move the graduation with the preset division cycle time T. If t≈T, the flow control valves 14 and 15 are left open. However, if t <T, the pusher 4 moves too fast, so the flow control valve 15 is closed. As a result, the oil will flow only through the flow control valve 14,
The flow rate decreases and the pusher 4 moves slowly. Conversely t
If> T, the pusher 4 moves too slowly, so the flow control valve 16 is also opened. As a result, the flow rate of the hydraulic circuit increases and the pusher 4 moves faster.

As described above, according to the second aspect of the invention , the feed speed can be finely adjusted for each divided cycle time without stopping the movement of the pusher 4, and the flow control valves 14, 15 arranged in parallel are provided. Since the speed is adjusted by opening and closing 16, there is no risk of speed changes due to oil temperature fluctuations or oil deterioration, unlike the conventional one using a single flow control valve.

[0017]

As described above, according to the present invention, the pushing speed of the pusher can be accurately and stably carried out even in the low speed region, whereby the conveying speed of the product to be fired in the furnace can be improved. Since it can be made uniform, there is no risk of overburning or underburning.
Further, according to the present invention, since it is not affected by the change of the oil temperature and the change of the viscosity of the oil unlike the conventional case, the equipment cost can be reduced. Therefore, the present invention, as a pusher driving device for a tunnel furnace that solves the conventional problems, has a great contribution to the industrial development.

[Brief description of drawings]

FIG. 1 is a sectional view of an entire tunnel furnace showing an embodiment of the present invention.

FIG. 2 is a control circuit diagram showing a main part of an embodiment of the first invention .

FIG. 3 is a control circuit diagram showing a main part of an embodiment of the second invention .

[Explanation of symbols]

 4 Pusher 6 Linear scale plate 7 Scale 8 Scale detection means 13 Timer 14 Flow control valve 15 Flow control valve 16 Flow control valve

Claims (2)

[Claims] 1. A linearly scaled plate having graduations of equal pitch is integrally attached to a hydraulically driven pusher, and a graduation detecting means for sending a signal to a hydraulic circuit each time the graduation is detected on the furnace body side. , Predetermined division cycle time
Includes a timer that activates the pusher each time to detect the scale
A pusher driving device for a tunnel furnace, comprising: a feed rate control means for stopping the pusher when receiving a signal from the means . 2. A hydraulically driven pusher having an equal pitch.
Attaching a linear scale plate with a scale to it
In addition, the hydraulic circuit is sent to the furnace side every time the scale is detected.
And a flow detector connected in parallel.
Depending on the signal from the scale detection means, the control valve
And a feed speed control means for opening and closing.
Pusher drive device for tunnel furnace .