JPS6151234B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for preventing a suction head from falling in a device for removing scum generated in hot metal, molten steel, etc.

During melting operations in steel mills, foundries, etc., scum floats to the surface of the molten metal. Therefore, unless this scum is removed before pouring,
Introduces harmful ingredients and results in defective products.
Therefore, a suction head connected to a suction device such as a vacuum pump or an exhaust fan is brought above the molten metal surface, and the scum on the molten metal surface is absorbed into the head, and cooling water is injected onto this suction scum to cool it and solidify it. However, a method is used to eliminate the scum that has solidified by cooling. According to this, the drawbacks of the conventional method are solved, but if the scum gets too close to the molten metal surface, the scum that has been sucked into the suction port of the head will block the suction port, and will be sprayed into the head and upward. The cooling water that was being sucked into the suction head will no longer be suctioned and will drip onto the molten metal from within the head, causing the molten metal to adhere to the suction head and suction pipe, making it impossible to carry out subsequent scum suction work. .

The first safety feature of a scum removal device is that the suction head is not immersed in hot water, so it is a condition that the suction head does not fall for a long period of time even when the oil pressure is low or during a power outage.

In view of this point, the present invention takes into account that a drop in oil pressure is caused by an abnormality in the hydraulic pump or damage to the hydraulic circuit, and installs a pressure gauge with a contact point near the hydraulic pump to detect a drop in oil pressure due to an abnormality in the pump. A pressure gauge with contacts is installed in the supply oil path, and another pressure gauge with contacts is installed in the oil path between the vertical movement cylinder and the solenoid valve that switches the vertical movement cylinder to detect a drop in oil pressure due to oil path damage, and the output of these contacts is used to connect the vertical movement cylinder This invention proposes a suction head lowering prevention device that closes a pilot check valve interposed in the hydraulic circuit of the suction head to prevent the suction head from lowering under any circumstances.

An embodiment of the present invention will be described below based on the drawings. Reference numeral 1 denotes a suction head for suctioning scum which is movable in the vertical and horizontal directions, and its vertical movement is performed by a cylinder 2 for vertical movement. 3
A pilot check valve is connected to the upward movement chamber 2a of the cylinder 2 which acts to move the suction head 1 upward, and is connected through a stop valve 4 and a sequence valve 5 to a solenoid valve 6 for cylinder switching. Also, a lower movement chamber 2b of the cylinder 2 that acts to move the suction head 1 downward.
is connected to the cylinder switching solenoid valve 6 through a stop valve 7. Reference numeral 8 designates a switching valve interposed between the lower movement chamber 2b of the cylinder 2 and the pilot portion 3a of the pilot valve 3, and is energized when the hydraulic circuit is in operation to switch the switching valve to the pilot portion 3a of the pilot check valve 3. Pressurized oil is supplied to allow oil to drain from the upward movement chamber 2a of the cylinder 2. Furthermore, when the switching valve 8 is deenergized, the supply of pressure oil to the pilot section 3a is cut off, and the pilot check valve 3 closes the oil passage in the direction in which oil is drained from the upper movement chamber 2a. Lowering of the suction head 1 via 2 is prohibited. Note that the switching valve 8
Deenergization is performed by contact outputs from contact pressure gauges 12 and 14, which will be described later, or by a detection signal at the time of a power outage. Furthermore, when oil is supplied from the solenoid valve 6 to the upward movement chamber 2a of the cylinder 2, the sequence valve 5 smoothly performs the oil supply to allow the suction head 1 to rise rapidly, and drains oil from the upward movement chamber 2a of the cylinder 2 to the solenoid valve 6. This is to limit the speed of the drained oil and allow the suction head 1 to slowly descend. Oil is supplied to the lower moving chamber 2b or the upper moving chamber 2a of the cylinder 2 through the electromagnetic valve 6 from a hydraulic pump 10 driven by a motor 9. 11 is an unload relief valve.

Reference numeral 12 denotes a pressure gauge with a contact point provided in the oil passage between the stop valve 4 and the sequence valve 5 via a gauge damper 13, which detects a drop in oil pressure due to oil passage damage and generates a contact output. 14 is hydraulic pump 1
This is a pressure gauge with a contact point installed in the supply oil path near 0 via a gauge damper 15, and detects a drop in oil pressure due to pump abnormality and generates a contact output.

On the other hand, the hydraulic pump 10 is connected to a manual switching valve 19 through a flow control valve 16, an angle check valve 17, and a solenoid valve 18, and the two port outputs of the manual switching valve 19 are connected to a throttle check valve 20,
It is connected through 21 to the input side of stop valves 4 and 7 provided in the oil passage of the cylinder 2. 2
2 is an accumulator connected to the input side of the solenoid valve 18 through a stop valve 23;
9 for emergency driving of the cylinder 2.

While the hydraulic circuit is currently operating, the switching valve 8 is energized;
The pilot check valve 3 is released from closing, and the suction head 1 is freely raised and lowered by the cylinder 2. When an abnormality occurs in the hydraulic pump 10 or the hydraulic circuit, resulting in a drop in oil pressure, and the contact pressure gauge 14 or 12 detects this and generates a contact output, the switching valve 8 is deenergized and positioned at the position shown in the figure. Return to the pilot section 3 of the pilot check valve 3.
The pressure oil supplied to cylinder a is discharged and
The oil passage in the direction in which pressure oil is discharged from the upward movement chamber 2a is closed, and the suction head 1 is prohibited from lowering through the cylinder 2 under any circumstances. Also, in the event of a power outage, the switching valve 8 is deenergized and returns to the position shown in the figure, and the pilot check valve 3 is similarly closed to prohibit lowering of the suction head 1.

When the suction head 1 is prohibited from descending, the solenoid valve 6 is set to the neutral position to close the oil passage from the hydraulic pump 10 to the cylinder 2, and then the stop valve 23 is opened and the accumulator 22 is set to the manual switching valve. If you contact 19, manual switching valve 1
By manual operation 9, the suction head 1 can be raised in an emergency manner via the cylinder 2. In addition, by deenergizing the switching valve 8, slow descent can be performed in an emergency.

As described above, according to the present invention, when the oil pressure is low, the suction head for suctioning scum can be prohibited from descending for a long period of time, so that the suction head does not accidentally get too close to the upper surface of the molten metal or immerse in the molten metal. In addition, the lowering can be similarly prohibited even during a power outage, and the solenoid valve 6 and cylinder 2
The cylinder 2 can be raised by the manual valve 19 in any case if there is no circuit breakage during the period.

[Brief explanation of the drawing]

The drawing is a configuration diagram showing an embodiment of the present invention. 1... Suction head for scum suction, 2...
Vertical movement cylinder, 2a, 2b...Upper movement and lower movement chamber, 3...Pilot check valve, 3a...Pilot part, 5...Sequence valve, 6...Solenoid valve, 8...Switching valve, 10... Hydraulic pump, 12,
13...Pressure gauge with contacts.

Claims (1)

[Claims] 1. A pilot check valve and a sequence valve are provided in an oil passage connected to an upper movement chamber that acts to raise the suction head of a cylinder that drives a suction head for scum suction that is movable in the vertical direction, and Between the oil passage connected to the lower movement chamber that acts to lower the suction head and the pilot part of the pilot check valve, when the cylinder is operated, the pilot part is supplied with oil and the oil passage is closed by the pilot check valve. A switching valve is provided which is energized to release the
Furthermore, pressure gauges with contacts are provided in the oil passage between the pilot check valve and the sequence valve and in the supply oil passage near the oil supply pump, and the switching valve is deenergized by the contact output of the pressure gauge with contacts that occurs when the oil pressure decreases. 1. A suction head lowering prevention device for a scum removal device, characterized in that the oil passage is closed via a pilot check valve to prevent the suction head from lowering.