JP3569834B2 - Operation control device for viscous fluid pump - Google Patents

Description

[0001]
[Industrial applications]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an operation control device for a viscous fluid pump used when a transportation pipe is blocked during transportation of a viscous fluid such as concrete to operate the viscous fluid pump.
[0002]
[Prior art]
A viscous fluid pump in which viscous fluid such as concrete in a hopper is alternately sucked and discharged by two fluid pressure feeding cylinders is provided with a slide valve type as a suction and discharge valve for switching between suction and discharge. A type employing a valve type is conventionally known.
[0003]
A conventional viscous fluid pump in which the suction and discharge valve is of a swing valve type, as shown in an example in FIG. 3, swings a swing pipe 13 in a hopper 1 provided with two suction and discharge ports 2 arranged side by side at a lower portion of a front surface. The two fluid pumping cylinders 3 and 4 are arranged so as to be movably accommodated and communicate with the two suction / discharge ports 2 in parallel. The two main hydraulic cylinders 6 and 7 are connected via the cleaning chamber 5, and the hydraulic pump pistons 8 and 9 housed in the hydraulic pump cylinders 3 and 4 are connected to the main hydraulic pistons in the main hydraulic cylinders 6 and 7. 10 and 11 are integrally connected via a single piston rod 12, and the main hydraulic pistons 10 and 11 are alternately advanced and retracted, whereby the fluid pressure feeding pistons 8 and 9 are alternately advanced and retracted. Fluid pressure feeding cylinders 3 and 4 alternately switch to suction and discharge. Yes in the so that the viscous fluid 15 in the fluid pumping cylinder became discharge side are to be pumped through the transport pipe 14 from the oscillating tube 13.
[0004]
In such a viscous fluid pump, when a blockage of the viscous fluid occurs, a reverse rotation operation is performed to return the viscous fluid 15 in the transport pipe 14 to the hopper 1 as a method of releasing the blockage. A pressure sensor 17 is provided on a supply side line portion 16a of a pressure oil supply / discharge line 16 to the main hydraulic cylinder 6 or 7, the pressure sensor 17 is connected to a controller 18, and a pressure oil supply is performed by a command from the controller 18. The reverse rotation operation is performed by switching the electromagnetic four-way valve 19 assembled in the discharge line 16. 20 is a sealed circuit, 21 is a tip hose, 22 is a hydraulic pump, and 23 is a tank.
[0005]
However, when the viscous fluid pump is operated in the reverse direction, if the transport pipe 14 has a rising portion and a height difference exists, a back pressure accompanying the height difference is applied to the viscous fluid 15 in the transport pipe 14 which is caused to flow backward by suction. Therefore, a push-back force due to the back pressure is further applied to the fluid-pressure-feeding piston 8 or 9 that is retracted by the reverse rotation operation. If the back pressure is excessive, the main hydraulic cylinder 6 or 7 or The problem that a large impact acts on a hydraulic device or the like is caused.
[0006]
Conventionally, as shown in an example in FIG. 4, a pilot switching valve 24 having a variable throttle portion 24a in which a throttle action is given to return of pressure oil by switching a port is incorporated in the pressure oil supply / discharge line 16. And, in order to operate the pilot switching valve 24, there is provided an electromagnetic valve 25 which is excited and switched at the time of reverse operation, and when the operation is switched to the reverse operation and the electromagnetic valve 25 is excited, the pilot switching valve 24 is activated by the pilot pressure. By being switched so that the variable throttle portion 24a is positioned on the return line portion 16b, the pressure oil returned to the tank 23 through the return line portion 16b is given a throttle effect, and thus the main hydraulic cylinders 6, 7 are provided. And the like, which can reduce the impact acting on the like.
[0007]
[Problems to be solved by the invention]
However, the throttle of the variable throttle portion 24a of the pilot switching valve 24 must be adjusted according to the magnitude of the back pressure of the viscous fluid flowing backward, but this adjustment depends on the experience and intuition. There is a problem that reliable control is difficult.
[0008]
In view of the above, according to the present invention, in the case where the viscous fluid causes blockage in the transport pipe and performs the reverse rotation operation, the amount of restriction of the return line portion is appropriately adjusted according to the magnitude of the back pressure acting on the viscous fluid flowing backward. It tries to be able to adjust.
[0009]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the present invention is configured such that two fluid pressure feeding cylinders for alternately sucking and discharging a viscous fluid by switching suction and discharge valves are alternately advanced and retracted by two main hydraulic cylinders. And when the viscous fluid is blocked in the transport pipe connected to the fluid pressure feeding cylinder via the suction / discharge valve, the operation of the two main hydraulic cylinders is reversed to perform the reverse rotation operation. An electromagnetic proportional relief valve is provided in the return line portion of the pressure oil supply / discharge line to the two main hydraulic cylinders in the viscous fluid pump as described above, and the back of the viscous fluid flowing backward during reverse operation is provided in the transport pipe. A back pressure sensor for detecting pressure is attached, and further a controller is provided which adjusts the set pressure of the electromagnetic proportional relief valve based on a signal from the back pressure sensor.
[0010]
Further, instead of attaching the back pressure sensor to the transport pipe, a configuration in which a back pressure sensor is attached to the return line portion of the pressure oil supply / discharge line may be adopted.
[0011]
[Action]
When the viscous fluid is clogged inside the transport pipe and the reverse operation is performed, the back pressure of the viscous fluid flowing backward is detected by the back pressure sensor, and the command of the electromagnetic proportional relief valve is issued by the controller based on the signal. The set pressure is adjusted. As a result, an appropriate throttling action is given to the return of the pressure oil, and the reverse operation is stably performed under the optimum conditions.
[0012]
【Example】
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0013]
FIG. 1 shows an embodiment of the present invention. As shown in FIG. 3, an electromagnetic four-way valve 19 in a pressure oil supply / discharge line 16 is controlled by a command from a controller 18 based on a signal from a pressure sensor 17. In the return line portion 16b of the pressurized oil supply / discharge line 16 to the tank 23 in the viscous fluid pump in which the reverse rotation operation can be performed by switching between the electromagnetic proportional relief valve (a counter balance valve in the embodiment). 26), and a line 28 for returning pressurized oil from the electromagnetic proportional relief valve 26 to the tank 23 is provided. An electromagnetic valve 27 for communicating and shutting off the line 28 is provided in the middle of the line 28. When the viscous fluid pump is switched to the reverse operation, it is excited so as to cut off the line 28, and the line 28 is cut off by the switching of the solenoid valve 27 so that the electromagnetic Example: The relief valve 26 is turned on, a back pressure sensor 29 is attached to the root of the transport pipe 14, and the set pressure of the electromagnetic proportional relief valve 26 is set based on the detection value of the back pressure sensor 29. A controller 30 having a function as an electromagnetic proportional relief valve amplifier for adjusting is used instead of the controller 18.
[0014]
In the present embodiment, as shown in FIG. 2, the back pressure sensor 29 is a spring cylinder in which the piston rod 31 projects outward on the wall of the transport pipe 14 in accordance with the pressure of the viscous fluid 15. And a wiper 34 of a potentiometer 35 in which a wiper 34 slides on a resistance element 33 is attached to a distal end of the piston rod 31.
[0015]
During the normal operation of the viscous fluid pump, the solenoid of the solenoid valve 27 is not excited, and the solenoid proportional relief valve 26 is not operated. Is returned from the electromagnetic proportional relief valve 26 of the return line portion 16b to the tank 23 via the line 28 and the electromagnetic valve 27 without being subjected to the throttling action.
[0016]
Now, when the viscous fluid 15 is blocked in the transport pipe 14, a pressure increase is detected by the pressure sensor 17 of the supply side line portion 16a, and a signal thereof is input to the controller 30, and a command from the controller 30 is issued. The reverse operation is performed by switching the electromagnetic type four-way valve 19 at the same time. At this time, simultaneously, a switching command is sent from the controller 30 to the electromagnetic valve 27 to cut off the line 28, so that the electromagnetic proportional relief valve 26 is activated. Thereby, the pressure oil flowing through the return line portion 16b is returned to the tank 23 while being subjected to the throttling action by the electromagnetic proportional relief valve 26.
[0017]
In the above description, when the transport pipe 14 is in the upright state, a push-back force due to the back pressure is applied to the viscous fluid 15 which is about to flow backward into the fluid pressure feeding cylinder 3 or 4 by the reverse rotation operation. At this time, a back pressure is detected by a back pressure sensor 29 attached to the root of the transport pipe 14, and a control command is sent from the controller 30 to the electromagnetic proportional relief valve 26 based on the signal, so that the electromagnetic proportional relief The set pressure of the valve 26 is adjusted according to the back pressure. Therefore, an appropriate throttling effect can be given to the pressure oil returned to the tank 23 through the return line portion 16b by the electromagnetic proportional relief valve 26, and the impact due to the back pressure acting on the main hydraulic cylinders 6, 7 and the like can be reduced. Can be eased.
[0018]
In a viscous fluid pump, a blockage problem is an unavoidable phenomenon, and a reverse operation is required to cancel the problem. However, as described above, the magnitude of the back pressure of the viscous fluid 15 flowing backward causes the electromagnetic proportional relief to occur. By performing control to increase or decrease the set pressure of the valve 26, a reliable and stable reverse operation can be performed even during unmanned operation.
[0019]
In the above embodiment, the case where the back pressure sensor 29 is attached to the transport pipe 14 is shown. However, as shown by a two-dot chain line in FIG. 1, the back pressure sensor 29 is attached to the return line portion 16b of the pressure oil supply / discharge line 16. Of course, various changes can be made without departing from the scope of the present invention.
[0020]
【The invention's effect】
As described above, according to the operation control device for a viscous fluid pump of the present invention, an electromagnetic proportional relief valve is provided in a return line portion of a pressure oil supply / discharge line to a main hydraulic cylinder, and a transport pipe or a return line portion is provided. A back pressure sensor is attached, and the set pressure of the electromagnetic proportional relief valve can be adjusted by a command from a controller based on the signal of the back pressure sensor. When the operation is performed, an appropriate throttling action according to the back pressure of the viscous fluid flowing backward can be given to the pressure oil on the return side. Even if it does, an excellent effect that the impact acting on the main hydraulic cylinder and the like can be reduced and a stable reverse operation can be performed under the optimum condition is exhibited.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing one embodiment of an operation control device for a viscous fluid pump of the present invention.
FIG. 2 is an enlarged view showing an example of a back pressure sensor.
FIG. 3 is a schematic diagram showing an example of a conventional example.
FIG. 4 is a schematic diagram showing another example of the conventional example.
[Explanation of symbols]
3, 4 Fluid pressure feeding cylinder 6, 7 Main hydraulic cylinder 14 Transportation pipe 16 Pressure oil supply / discharge line 16b Return line 26 Electromagnetic proportional relief valve 29 Back pressure sensor 30 Controller

Claims (2)

The two fluid pressure feeding cylinders for alternately sucking and discharging the viscous fluid by switching the suction / discharge valve are alternately moved forward and backward by two main hydraulic cylinders, and the fluid pressure feeding is performed via the suction / discharge valve. When the viscous fluid is blocked inside the transport pipe connected to the cylinder for operation, the two main hydraulic cylinders are reversed in operation to perform a reverse rotation operation so that the two main hydraulic cylinders are operated in reverse. An electromagnetic proportional relief valve is provided on the return line portion of the pressure oil supply / discharge line to the main hydraulic cylinder, and a back pressure sensor for detecting a back pressure of a viscous fluid flowing backward during the reverse rotation operation is attached to the transport pipe, An operation control device for a viscous fluid pump, further comprising a controller that adjusts a set pressure of the electromagnetic proportional relief valve based on a signal of the back pressure sensor. 2. The viscous fluid pump operation control device according to claim 1, wherein a back pressure sensor is attached to a return line portion of the pressure oil supply / discharge line instead of attaching the back pressure sensor to the transport pipe.

Images