JPH08284810A - Operation controller for viscous fluid pump - Google Patents

Abstract

PURPOSE: To suitably adjust the throttle amount of a returning line part according to back pressure of viscous fluid to flow back in the reverse operation. CONSTITUTION: An electromagnetic four-way valve 19 is provided on a pressure oil supplying and discharging line 16 of main oil pressure cylinders 6, 7 for alternately switching intake and discharge valves, and the electromagnetic four-way valves 19 is switched as to reverse the operation when blockage is generated on viscous fluid 15 in a transporting piping 14. An electromagnetic proportional relief valve 26 is provided on a returning line part 16b of the pressure oil supplying and discharging line 16, and a back pressure sensor 29 for detecting back pressure of viscous fluid 15 to flow back in the reverse operation is attached to the transporting piping 14. A controller 30 is provided for adjusting the set pressure of the electromagnetic proportional relief valve 26 on the basis of a signal of the back pressure sensor 29.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an operation control device for a viscous fluid pump, which is used when the transportation pipe is clogged during the transportation of a viscous fluid such as concrete so as to operate the viscous fluid pump. It is about.

[0002]

2. Description of the Related Art A viscous fluid pump in which a viscous fluid such as concrete in a hopper is alternately sucked and discharged by two fluid pressure feeding cylinders is a slide valve type as a suction and discharge valve for switching suction and discharge. The one adopting the one of the above and the one of the swing valve type has been conventionally known.

A conventional viscous fluid pump having a swing valve type suction and discharge valve has a swing pipe in a hopper 1 in which two suction and discharge ports 2 are arranged side by side in a lower front portion as shown in FIG. 13 is swingably housed and the two suction / discharge ports 2 are provided.
, Two fluid pressure feeding cylinders 3 and 4 are arranged in parallel to communicate with each other, and the two fluid pressure feeding cylinders 3 and 4 are connected to two main hydraulic cylinders 6 via a cleaning chamber 5. Connect 7
The fluid pressure feeding pistons 8 and 9 housed in the fluid pressure feeding cylinders 3 and 4 are integrally connected to the main hydraulic pistons 10 and 11 in the main hydraulic cylinders 6 and 7 via one piston rod 12 respectively. , By alternately moving the main hydraulic pistons 10 and 11 forward and backward,
Are alternately moved forward and backward to allow fluid pressure feeding cylinders 3 and 4
Are alternately switched to suction and discharge, and the viscous fluid 15 in the fluid pressure feeding cylinder on the discharge side is pressure-fed from the rocking pipe 13 through the transportation pipe 14.

In such a viscous fluid pump, when clogging of the viscous fluid occurs, a reverse operation is performed to return the viscous fluid 15 in the transportation pipe 14 to the hopper 1 as a method of releasing it. As a means, a pressure sensor 17 is provided on the supply side line portion 16a of the 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 command is issued from the controller 18. An electromagnetic four-way valve 19 installed in the pressure oil supply / discharge line 16 is switched to perform a reverse rotation operation. 20 is a sealed circuit, 21 is a tip hose, 22 is a hydraulic pump, and 23 is a tank.

However, when the viscous fluid pump is reversely operated, if there is a rising portion in the transportation pipe 14 and there is a height difference, the transportation pipe 1 is made to flow backward by suction.
Since the back pressure due to the height difference is applied to the viscous fluid 15 in 4,
A pushing-back force due to the back pressure is further applied to the fluid pressure-feeding piston 8 or 9 which is retracted by the reverse rotation operation, and when the back pressure is excessive, the main hydraulic cylinder 6 or 7 or the hydraulic equipment. The problem that a big shock acts on etc. is caused.

Therefore, conventionally, as shown in an example in FIG. 4, a pilot switching valve having a variable throttle portion 24a in the pressure oil supply / discharge line 16 is provided with a throttle action for returning the pressure oil by switching the port. In order to incorporate 24 and operate the pilot switching valve 24, a solenoid valve 25 that is excited and switched during reverse operation is provided. When the reverse operation is switched and the solenoid valve 25 is excited, pilot switching is performed by pilot pressure. The valve 24 is switched and the variable throttle portion 24a is positioned at the return line portion 16b, so that the tank 23 passes through the return line portion 16b.
The pressure oil returned to the
A system is adopted in which the impact acting on the main hydraulic cylinders 6, 7 etc. can be alleviated.

[0007]

However, the throttle of the variable throttle portion 24a of the pilot switching valve 24 must be adjusted according to the back pressure of the viscous fluid that flows backward, but this adjustment depends on experience and intuition. Therefore, there is a problem that it is difficult to perform reliable control according to the magnitude of the back pressure.

Therefore, according to the present invention, when the viscous fluid is clogged in the transportation pipe and the reverse operation is performed, the throttle amount of the return line portion is increased according to the back pressure acting on the viscous fluid flowing backward. Is to be able to adjust properly.

[0009]

In order to solve the above problems, the present invention provides two fluid pressure feeding cylinders for alternately sucking and discharging a viscous fluid by switching intake and discharge valves.
Two main hydraulic cylinders are alternately operated to move forward and backward, and when the viscous fluid is clogged inside the transportation pipe connected to the fluid pressure feeding cylinder via the suction and discharge valve, An electromagnetic proportional relief valve is provided at the return line portion of the pressure oil supply / discharge line to the two main hydraulic cylinders in the viscous fluid pump configured to perform the reverse operation by reversing the operation of the main hydraulic cylinder, and A back pressure sensor for detecting the back pressure of the viscous fluid that flows backward during reverse operation is attached to the transportation pipe, and further, the set pressure of the electromagnetic proportional relief valve is adjusted based on the signal of the back pressure sensor. It is configured to include the controller.

Further, instead of attaching the back pressure sensor to the transportation pipe, the back pressure sensor may be attached to the return line portion of the pressure oil supply / discharge line.

[0011]

[Function] When the viscous fluid is clogged inside the transportation pipe and the reverse operation is performed, the back pressure of the back-flowing viscous fluid is detected by the back pressure sensor, and the command from the controller based on the signal causes electromagnetic proportional The set pressure of the relief valve is adjusted. As a result, an appropriate throttling action is given to the return of the pressure oil, so that the reverse rotation operation is stably performed under the optimum conditions.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of the present invention, and like the one shown in FIG. 3, an electromagnetic system in the pressure oil supply / discharge line 16 is instructed by a controller 18 based on a signal from the pressure sensor 17. In the viscous fluid pump in which the four-way valve 19 is switched to enable the reverse operation, the pressure oil supply / discharge line 16
In the middle of the return line portion 16b to the tank 23, an electromagnetic proportional relief valve (in the embodiment, a cowter balance valve is shown)
26 is provided, and a line 28 for returning the pressure oil from the electromagnetic proportional relief valve 26 to the tank 23 is provided, and the line 28 is connected and shut off in the middle of the line 28.
The electromagnetic valve 27 is energized to shut off the line 28 when the viscous fluid pump is switched to the reverse rotation operation. By shutting off the line 28 by switching the solenoid valve 27, an electromagnetic proportional relief is provided. Valve 26 is O
An electromagnetic proportional relief that is operated N times and that has a back pressure sensor 29 attached to the root of the transportation pipe 14 and that adjusts the set pressure of the electromagnetic proportional relief valve 26 based on the detection value of the back pressure sensor 29. A controller 30 having a function as a valve amplifier is used instead of the controller 18.

In this embodiment, the back pressure sensor 29 is arranged so that the piston rod 31 projects outward on the wall portion of the transportation pipe 14 in accordance with the pressure of the viscous fluid 15, as shown in FIG. The wiper 34 of the potentiometer 35 is equipped with a displacement gauge 32 such as a spring cylinder, and the wiper 34 slides on the resistance element 33.
Is attached to the tip of the piston rod 31.

During normal operation of the viscous fluid pump, the solenoid valve 2
Since the solenoid 7 is not excited, the electromagnetic proportional relief valve 26 is not operating. Therefore, the pressure oil on the return side due to the forward and backward movements of the main hydraulic cylinders 6 and 7 is not electromagnetic on the return line portion 16b. It is returned from the proportional relief valve 26 to the tank 23 via the line 28 and the solenoid valve 27 without being subjected to the throttling action.

Now, when the viscous fluid 15 is clogged inside the transportation pipe 14, the pressure sensor 17 in the supply side line portion 16a.
The pressure increase is detected by the controller, the signal is input to the controller 30, and the electromagnetic four-way valve 19 is switched by the command from the controller 30 to perform the reverse rotation operation. At this time, the controller 30 simultaneously A switching command is sent to the solenoid valve 27 to cut off the line 28, whereby the solenoid proportional relief valve 26 is activated. As a result, 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.

In the above, when the transportation pipe 14 is in the upright state, the fluid pressure feeding cylinder 3 is driven by the reverse rotation operation.
Alternatively, a back-pressure pushing-back force is added to the viscous fluid 15 that is about to be backflowed into
Back pressure sensor 29 attached to the root of the transport pipe 14
The back pressure is detected by, and the control command is sent from the controller 30 to the electromagnetic proportional relief valve 26 based on the signal, so that the set pressure of the electromagnetic proportional relief valve 26 is adjusted according to the back pressure. . Therefore, the return line portion 1
The electromagnetic proportional relief valve 26 can apply an appropriate throttling action to the pressure oil returned to the tank 23 through the 6b, and the impact due to the back pressure acting on the main hydraulic cylinders 6 and 7 can be mitigated. .

In the viscous fluid pump, the problem of obstruction is unavoidable, and reverse operation is required to clear the problem.
By controlling to increase or decrease the set pressure of the electromagnetic proportional relief valve 26 depending on the magnitude of the back pressure of 5, the reliable and stable reverse operation can be performed even in the unmanned operation.

Although the back pressure sensor 29 is attached to the transportation pipe 14 in the above embodiment, it is attached to the return line portion 16b of the pressure oil supply / discharge line 16 as shown by the chain double-dashed line in FIG. Needless to say, various modifications may be made without departing from the scope of the present invention.

[0020]

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 the return line portion of the pressure oil supply / discharge line to the main hydraulic cylinder,
Further, a back pressure sensor is attached to the transportation pipe or the return line portion, and the set pressure of the electromagnetic proportional relief valve can be adjusted by a command from the controller based on the signal of the back pressure sensor. When the reverse operation is performed due to clogging of the viscous fluid, an appropriate throttling action according to the back pressure of the viscous fluid that flows backward can be applied to the pressure oil on the return side. Even if a large back pressure is generated due to the difference, the impact acting on the main hydraulic cylinder or the like can be alleviated, and a stable reverse rotation operation can be performed under optimum conditions, which is an excellent effect.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an 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 Transport piping 16 Pressure oil supply / discharge line 16b Return line section 26 Electromagnetic proportional relief valve 29 Back pressure sensor 30 Controller

Claims (2)

[Claims] 1. Two fluid pressure feeding cylinders for alternately sucking and discharging viscous fluid by switching intake and discharge valves.
Two main hydraulic cylinders are alternately operated to move forward and backward, and when the viscous fluid is clogged inside the transportation pipe connected to the fluid pressure feeding cylinder via the suction and discharge valve, An electromagnetic proportional relief valve is provided at the return line portion of the pressure oil supply / discharge line to the two main hydraulic cylinders in the viscous fluid pump configured to perform the reverse operation by reversing the operation of the main hydraulic cylinder, and A back pressure sensor for detecting the back pressure of the viscous fluid that flows backward during reverse operation is attached to the transportation pipe, and further, the set pressure of the electromagnetic proportional relief valve is adjusted based on the signal of the back pressure sensor. An operation control device for a viscous fluid pump, comprising: 2. The operation control device for a viscous fluid pump 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 transportation pipe.