JP2869345B2 - Waste extrusion machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an extruder for reducing or reducing the volume of industrial waste and other various wastes with a screw.

[0002]

2. Description of the Related Art FIG. 4 shows a conventional electric motor driven waste extruder.
A pair of screws 4 are arranged in a casing provided with a casing 3 having a pair of shafts, and a shaft at the rear end of each screw 4 is connected to a pair of gears provided in a gear box 5 so that the two screws 4 are in opposite directions. Linked to rotate at the same speed.

[0003] 6 is an electric motor fixed on the rear of the base 1,
Reference numeral 7 denotes a speed reducer, and the output shaft of the electric motor 6 and the input shaft of the speed reducer 7 are linked by a belt-type transmission means 9. A coupling 10 connects the output shaft of the speed reducer 7 with the shaft of one of the gears in the gear box 5.

[0004] In the above conventional example, waste crushed in advance by an appropriate crusher is removed from the hopper 2 to the casing 3.
When the input shaft of the speed reducer 7 is rotated by the electric motor 6 through the transmission means 9 while being put into the gear box, and the gear in the gear box 5 is rotated by the output shaft through the coupling 10, the left and right parts integrated with this are rotated. Screw 4 rotates to knead the waste and send it forward while compressing. If the waste is like a thermoplastic, by kneading,
It is discharged from the outlet at the front end of the casing 3 while melting and reducing the volume by self-heating or heating by a heater attached to the casing 3.

In the method of controlling the supply amount in the above-described extruder, a change in load is detected based on a change in a current consumption value of the motor, and when the current value increases, the supply amount of the waste decreases, and When the value decreases, the supply feeder is controlled to increase the amount of waste supplied. 6 (a) and 6 (b) are graphs showing the driving torque of the electric motor used in the conventional example, and FIG.
The vertical axis represents the torque rate, the horizontal axis represents the number of revolutions [rpm], and the curve represents the case where the rated torque is set to 1.

FIG. 6 (b) shows the torque ratio when the direct start torque of the electric motor is set to 1, the vertical axis represents the torque ratio, the horizontal axis represents the rotational speed rpm, and the curve I represents the reactor start. And the curve II shows the torque when the current is 50%.

[0007]

In the above-described method of controlling the supply feeder by changing the current value, it takes a long time to change the load due to an increase or decrease in the amount of waste supplied. It may be overloaded.

Further, the stopping torque when the motor stops due to overload is about 200% of the rated torque of the motor, but the starting torque of the motor is about 110%, which is smaller than the stopping torque, so that the motor is reversed. May not be possible. In this case, there is a problem that the extruder must be disassembled, which is extremely troublesome.

However, in the case of an extruder driven by an electric motor,
In order to change the rotation speed of the screw or increase the torque according to the load fluctuation, the reduction gear must be a variable reduction gear, and a device that automatically switches this reduction ratio according to the load fluctuation is required. Extremely complex and expensive equipment is required.

For this reason, conventionally, in order to cope with fluctuations in load, the supply amount of waste is limited so that the average operating power is 50% to 70% of the motor output. Therefore,
There is a problem in that the processing capacity of the extruder cannot be fully exhibited, so that the processing capacity is low.

An object of the present invention is to solve the above-mentioned problems of the conventional extruder by driving the screw hydraulically.

[0012]

In order to solve the above-mentioned problems, the present invention comprises a hydraulic drive means as a drive means for an extruder, and the hydraulic drive means has a variable displacement as a pump for generating a drive hydraulic pressure. Hydraulic pressure was supplied using a constant output type, and when the rotational speed of the screw of the extruder changed due to the change in load, the rotational speed of the hydraulic drive unit was detected in synchronization with the change in the rotational speed of the screw. The operation speed of the supply feeder that supplies waste to the extruder by the signal is increased if the rotation speed of the hydraulic drive means decreases.
Rolling speed is lowered, and the PID controller for PID control so as to varying <br/> into opposite effect when the rotational speed increases provided by the hydraulic pressure changes in the hydraulic drive means overloading of the extruder A configuration is adopted in which a pressure switch for detection is provided to detect foreign matter caught by the screw.

[0013]

In the above construction, when the screw is rotated by the hydraulic drive means while the waste previously crushed by an appropriate crusher is put into the casing of the extruder of the present invention from the hopper, the screw is turned into the waste. Kneaded and sent forward while compressing. When the waste is a thermoplastic plastic, the waste is discharged from the lower outlet of the front end of the casing while being melted by self-heating by kneading or dissolved by heating by a heater mounted on the casing to reduce the volume.

In the above operation, when the load applied to the screw fluctuates, the rotation of the screw changes due to the action of the variable capacity constant output type pump, and at the same time, the operating speed of the waste supply feeder to the hopper of the casing changes. The amount of waste supplied is suitable for the number of rotations of the screw.
Further, since a change in the hydraulic pressure of the hydraulic drive means is always detected, if an overload is detected, the drive means is stopped to prevent breakage of the extruder.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. In the embodiment shown in FIG. 1, the same portions as those in the conventional example of FIG. 4 are denoted by the same reference numerals, and description thereof will be omitted. Only different portions will be described. In this figure, a hydraulic motor 11 is fixed on the rear end of the base 1 as hydraulic drive means, and its output shaft is connected to the shaft of one of the gears in the gear box 5. And the piping 12 to the hydraulic motor 11,
13 is connected to the hydraulic unit 14.

FIG. 2 shows an example of the hydraulic unit 14, wherein 21 is an oil tank, 22 is a variable displacement constant output type hydraulic pump, and 25 is a motor for driving the same. An oil feed pipe 23 is connected to a P port of a 4-port, 3-ponge electromagnetic switching valve 24. The oil drain pipe 26 connected to the T port of the switching valve 24 communicates with the tank 21 via a return filter 27 and an oil cooler 29.

In the case of the embodiment, the hydraulic pump 22 has an oil supply of 900 liters / liter when the hydraulic pressure is 70 kg / cm ^2.
In the case of min, 210 kg / cm ² , automatic control is performed so that the oil supply amount is 300 liter / min. The other two ports of the switching valve 24 are connected to pipes 12 and 13 from the hydraulic motor 11.

Reference numeral 30 denotes a bypass pipe passing through the oil feed pipe 23 and the oil drain pipe 26, and a relief valve 3 which operates at 210k in the middle thereof.
1. An on-load valve 32 is provided, and a pressure gauge 34 and a pressure switch 35 operating at 150 kg / cm ² are provided in a pipe 33 branched from the oil feed pipe 23. When this pressure switch is operated, the switching valve 24 is operated. A hydraulic circuit is configured to reverse the hydraulic motor 11.

Next, the operation of the above embodiment will be described. First, the operation of the hydraulic unit 14 is started, and the hydraulic pressure is increased to a predetermined pressure.
For example, when the electromagnetic switching valve 24 in the neutral position is positioned on the normal rotation side under the condition of 70 kg / cm ² , the hydraulic motor 11 starts normal rotation, and both screws 4 in the casing 3 start normal rotation with each other. Under the condition that the screw 4 has been operated for a certain period of time, FIG.
Feeder 36 starts operation, and waste is discharged from hopper 2
And is discharged from the discharge port while being kneaded and compressed by the screw 4.

As described above, when the hydraulic motor 11 starts rotating, the output signal of the tach generator 37 for detecting the rotation is input to the PID controller 39 of FIG. 3, and the power source 42 of the drive motor 41 of the feeder 36 is controlled by the controller 39. Is controlled by

In other words, if the rotation of the screw 4 is within the range of the set value of the tach generator 37, the motor 41 also continues the steady operation, but the input amount from the feeder 36 increases and the load on the screw 4 increases. When the rotation speed decreases, the output signal from the tach
The ID controller 39 operates to send a signal to the power supply 42 to reduce the operation speed, and the rotation of the motor 41 is reduced to reduce the supply amount from the feeder 36. As a result, when the load on the screw 4 decreases and the rotation speeds up, the feeder 3 operates in the opposite manner to the above.
The supply from 6 increases.

Further, if an excessive load is applied to the screw 4 due to an excessive foreign substance biting between the screws 4 during the above operation, the oil pressure in the oil feed pipe 23 rises and the pressure switch 35 operates. The switching valve 24 is switched to the reverse rotation side. As a result, when the foreign matter is no longer caught, the hydraulic pressure drops, the pressure switch 35 returns, the switching valve 24 also returns to the normal rotation side, and the hydraulic motor 11 returns to normal operation.

When the action of the pressure switch 35 due to the above-mentioned foreign matter biting occurs three times in succession, the PID controller 3
9 is determined to be abnormal, and the biting failure is indicated by a failure display lamp, an alarm sound, etc., and the hydraulic motor 11 and the supply feeder 36 are displayed.
To stop. FIG. 5 is a graph showing the torque characteristics of the variable displacement constant output hydraulic pump, in which the vertical axis represents the hydraulic pressure P and kg / cm.
^{2. The} horizontal axis indicates the discharge rate Q, l / min.

In the above-described embodiment, the operation power can be constantly operated at 80 to 100% of the rated output of the electric motor for driving the hydraulic motor. In the case of an easily processable product, the number of rotations of the screw increases, the operation speed of the supply feeder increases, and the throughput can be increased. In the case of a difficult-to-treat object, since the operation is performed by lowering the rotation speed of the screw and increasing the torque, an overload stop (biting) does not occur with a slightly difficult object. Since the torque at the time of the reverse rotation is larger than the torque of the screw at the time of stopping the normal rotation due to the biting, the biting can be easily eliminated. Stable operation is possible even for wastes whose physical properties (difficulty of treatment) are not uniform.

[0025]

As described in detail above, the extruder of the present invention drives the hydraulic drive means with a variable displacement constant output type pump to rotate the screw, the load fluctuates, and the rotational speed of the screw decreases. it is so arranged to change the driving speed of the rotational speed synchronization with the supply feeder to a change in the change, the supply amount of the waste which is suitable for the rotational speed of the scan clew is obtained.

[Brief description of the drawings]

FIG. 1 is a partially longitudinal plan view of an embodiment.

FIG. 2 is a hydraulic circuit diagram of the above.

FIG. 3 is also a control system diagram

FIG. 4 is a partially longitudinal plan view of a conventional example.

FIG. 5 is a table showing torque characteristics of a hydraulic pump.

FIG. 6 is a table showing the driving torque of the electric motor.

[Explanation of symbols]

 2 Hopper 4 Screw 5 Gear Box 11 Hydraulic Motor 14 Hydraulic Unit 22 Hydraulic Pump 24 Solenoid Switching Valve 35 Pressure Switch 36 Supply Feeder 39 PID Controller

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) B29B 17/00-17/02 B09B 3/00 B29C 47/92 B30B 9/14

Claims (1)

(57) [Claims] 1. An extruder configured to reduce or solidify waste volume, comprising a hydraulic drive unit as a drive unit, wherein the hydraulic drive unit is a variable displacement constant output type as a pump for generating hydraulic pressure. When the rotation speed of the screw of the extruder changes due to a change in load and the rotation speed of the screw of the extrusion molding machine changes, the signal indicating the rotation speed of the hydraulic drive means is synchronized with the change in the rotation speed of the screw. The operation speed of the supply feeder that supplies waste to the extruder is operated if the rotation speed of the hydraulic drive unit decreases.
A PID controller is provided for performing PID control so as to reduce the speed and change the operation to the opposite operation when the rotation speed increases, and a pressure switch for detecting an overload of the extruder based on a change in the hydraulic pressure of the hydraulic drive means is provided. A waste extruder, characterized in that foreign matter caught by a screw is detected.