JPS62167812A - Method for controlling lifting for dh degassing - Google Patents

Abstract

PURPOSE:To enable smooth operation in the deceleration stage and to prevent the generation of a mechanical damage by gradually decreasing the discharge rate of a variable capacity type hydraulic pump and controlling the lifting speed of a hydraulic lifting device in the stage of transfer from a high speed region to a low speed region. CONSTITUTION:A control panel 23 generates an analog electric signal (b) and a comparator 30 emits a voltage difference b-d with a feedback signal (d) from a tilting angle detector 29 to a servocontrol amplifier 28 when a vacuum vessel 1 is at a top dead point position 34 and a start command signal (e) enters the control panel 23. The amplifier 28 controls a pilot valve 26, the valve 26 controls a control valve 25 and further the valve 25 controls a control cylinder 24, respectively, thereby proportionally changing the tilting angle theta to the electric signal (b). The tilting angle theta is maintained constant and the vacuum vessel 1 descends at the specified high speed when the signal (b) is made constant on gradual increase of the tilting angle theta. A deceleration command signal (g) enters the panel 23 and the signal (b) and the angle theta decrease gradually. The speed of the vessel 1 decreased and when the signal (b) is zero, the vessel 1 stops at a bottom dead point 35. The vessel 1 does not receive shock in the stage of stopping.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention provides a method for quickly and smoothly raising and lowering a vacuum chamber in vacuum degassing equipment, vacuum processing refining equipment, etc.
This invention relates to a method for controlling elevation in H degassing.

[Prior art 1 DI-1 degassing equipment, which has been conventionally used to remove impurity gas in molten metal, is rotatable via a vacuum chamber 1 and a fulcrum 2, as shown in Fig. 3, for example. A lever 4 supported by a vacuum tank 1 at one end and a counterweight 3 at the other end, and a hydraulic drive device 5 that drives the end of the lever 4 on the counterway 1 side up and down from below. The hydraulic drive device 5 includes a hydraulic cylinder 6, a hydraulic pump 7, a switching valve 8, an oil tank 9, and the like.

When operating the DH degassing equipment, the inside of the vacuum chamber 1 is kept in a vacuum and the bottom of the vacuum chamber is placed inside the pot 10. Shown in Figure 4 while submerged in $112? I drive the vacuum chamber 1 up and down in the vertical direction according to the gastric descent pattern (arrow a) to separate impure gas from the molten steel 12 sucked up into the chamber, and release this gas to the outside through the exhaust duct 13 provided at the top of the vacuum chamber 1] Ji
I want it to come out (arrow j). In addition, in Figure 4,
9 indicates a high speed region, 9 indicates a deceleration region, and Z indicates a stop period.

[Problem to be solved by the invention 1 However, the above-mentioned equipment had the following problems.

(1) Because the material involved in the vertical movement of the vacuum chamber 1 is very large (approximately 800 tons) and the control of the hydraulic pump 7 is insufficient, the vacuum chamber 1 moves from the high speed region x to the deceleration region y.
There is a risk that the shock will be large and mechanical damage will occur.

(fi) As a result of the previous item, the lifting speed of the vacuum chamber 1 is limited, and the processing capacity of the equipment cannot be fully utilized.

[Means for solving the problems] The present invention has been made to solve the above-mentioned problems.
The gist is that in the lift control method for DHI gas, which drives the vacuum chamber up and down using a hydraulic lifting device and uses the vacuum inside the vacuum chamber to suck up molten metal into the vacuum chamber and separate impurity gas, the discharge amount is A hydraulic lift device is driven using a program-controlled variable displacement ω-type hydraulic pump, and the discharge amount of the hydraulic pump is gradually decreased when the vacuum chamber is moved from a high-speed region to a deceleration region.

[Function] When moving the vacuum chamber from the high speed region to the deceleration region, the discharge amount of the variable displacement hydraulic pump is gradually reduced.
Inertial force can be reduced and operation can be made smoother. Furthermore, since the lifting speed in the high-speed region can be increased, the processing capacity of the equipment can be fully utilized.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings. In addition, in the figure, the same reference numerals and symbols are used for the same parts as the respective parts of the degassing equipment used when explaining the conventional example.

An example of a device for carrying out the method of the present invention will be explained with reference to FIGS. 1 and 2. In the figures, 21 is a variable displacement ω-type hydraulic pump, and 22 is a device that proportionally controls the tilting angle of this hydraulic pump 21. control device (shown in phantom), 2
3 receives and receives electrical signals from a transmitter (not shown), and sends a series of analog electrical signals (see the upper row of FIG. 2) to a control device v1 according to a program that defines changes in the tilt angle θ over time.
This is the control panel that sends data to 22.

The control device 22 includes a control cylinder 24 that drives a swash plate (not shown) of the hydraulic pump 21 to change the tilt angle θ, a control valve 25 that supplies control pressure oil to the control cylinder 24, and this control valve. Send the electric signal C to the pilot valve 26 of 25,
The servo amplifier 28 that drives the spool 27 of the control valve receives an analog electric signal sent from the control panel 23 and an electric signal (feedback signal) d equivalent to the actual tilt angle sent from the tilt angle detector 29. a comparator 30 for comparing and outputting the difference to the servo amplifier 28; It consists of a pressure oil supply pump 32 for Ib1Jtll, an oil tank 33, etc., and a control valve 25, a pilot valve 26, and a servo amplifier 28 constitute a proportional control valve.

Next, the implementation of this method and the operation of the above-mentioned control system will be explained. Now, when the vacuum W11 is at the top dead center position 34, the start command signal e is sent from the transmitter to the control board 23.
, the control 20 panel 23 generates the analog electrical signal shown in the upper part of FIG. The servo amplifier 28 controls the pilot valve 26, and the pilot valve 26 controls the control valve 25.
Further, the control valves 25 respectively control the 1llll# cylinders 24, and the tilting angle θ changes in proportion to the magnitude of the analog electrical signal.

In this way, the tilting angle θ increases successively, and after the elapse of time t1, the analog electrical signal becomes constant, and therefore the tilting angle θ
is also held constant, and the vacuum chamber 1 is maintained at a constant high speed (approximately 15ffi).
/1ain) to make a downward movement.

Then, after a predetermined time t2 has elapsed after the activation command signal C is issued, the deceleration command signal g is inputted to the control I panel 23, the analog electric signal S gradually decreases, and the tilt angle θ also gradually decreases. The speed of the vacuum chamber is reduced as shown in FIG. 2, and when the analog electrical signal 1 becomes zero, the vacuum chamber 1 stops at the bottom dead center position 35 with zero acceleration. Therefore, there is almost no shock when the vacuum chamber 1 stops, and there is no risk of damage.

After that, when the command signal to start raising the vacuum WJ1 is issued, the control panel 23 emits another analog electric signal h (see the upper part of Fig. 2), and the vacuum chamber 1 rises according to this signal, and continues for a predetermined period of time. When , the vehicle decelerates sequentially and stops at the top dead center position 34 with zero acceleration.

Since the analog electric signals S and H are all set in consideration of the operating characteristics of the hydraulic system and the inertia purchase price of the moving object, it is possible to realize i1+ control according to the program.

It should be noted that the present invention is not limited only to the above-described embodiments, and it goes without saying that various changes can be made without departing from the gist of the present invention.

"Effects of the Invention" As described above, the present invention exhibits the following excellent effects.

(D) When transitioning from a high-speed range to a low-speed range, the discharge amount of the variable displacement hydraulic pump is gradually reduced to control the lifting speed of the hydraulic lift drive device, so operation during deceleration is performed smoothly and damage can be avoided. can be prevented.

0) By increasing the vertical speed of the vacuum chamber in the high-speed region, processing capacity can be increased and the degassing effect can be enhanced.

[Brief explanation of drawings]

1 and 2 show an embodiment of the present invention, FIG. 1 is an explanatory diagram of a hydraulic and electric circuit showing an example of an apparatus for carrying out the method of the present invention, and FIG. 2 is an explanatory diagram of a hydraulic and electric circuit. FIG. 3 is an explanatory diagram showing the correspondence between the analog electrical signal generated by the 5111 and the vertical movement of the vacuum chamber, FIG. 3 is an explanatory diagram of a conventional DH degassing device, and FIG. 4 is an explanatory diagram of the vertical movement pattern of the vacuum chamber. In the figure, 1 is a vacuum chamber, 6 is a hydraulic cylinder, 12 is molten steel, 2
1 indicates a variable displacement hydraulic pump.

Claims (1)

[Claims] 1) In a lifting control method for DH degassing, in which a hydraulic lifting device is used to drive the vacuum chamber up and down and the vacuum inside the chamber is used to suck up molten metal into the vacuum chamber and separate impurity gas, the discharge amount is controlled by a program. Lifting control in DH degassing, characterized in that a hydraulic lifting device is driven using a variable displacement hydraulic pump, and the discharge amount of the hydraulic pump is gradually reduced when the vacuum chamber is moved from a high speed region to a deceleration region. Method.