JPS607218B2 - Fluid pipe rupture detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fluid pipe rupture detection device that can be used in a safety circuit of a remote-controlled hydraulic system, an automatically monitored hydraulic system, a general hydraulic system using a hydraulic power source, and particularly a continuous operation system. be.

Conventionally, when operating a hydraulic power source, a person directly turns on and off the power on the machine or remotely.

After the electric motor rotates and the hydraulic pump starts operating when the power is turned on, monitoring is limited to checking the pressure in the high-pressure side conduit from time to time. Therefore, when hydraulically driven equipment is operated remotely or when a single operator manages multiple equipment at the same time, sufficient monitoring is not possible, and accidents such as pipeline breaks have traditionally occurred. Even in such cases, the driver had no choice but to wait until the driver discovered the accident and stopped the hydraulic power source.

The present invention automatically monitors accidents in hydraulic equipment to minimize damage after an accident occurs.
Furthermore, the purpose is to improve work efficiency and safety by omitting the driver's monitoring work under normal conditions.

In order to achieve the above object, the present invention provides a flow detector in the low-pressure return line of the hydraulic power source, and detects whether there is a flow of working fluid in the return line by the flow detector. . On the other hand, on the load control side, a load operation detection means is installed to confirm that the hydraulic source is in an on-load state and that a control signal is being generated so that the load is driven by the high-pressure fluid discharged from the hydraulic source. It is being If the flow detector does not detect the flow of the working fluid in the load operation state detected by the load operation detection means,
When it is determined that a pipe line is damaged between the discharge pipe line and the return side pipe line of the hydraulic power source and fluid is leaking to the outside, for example, the electric motor of the hydraulic power source is stopped. An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing the configuration of an example of a device according to the present invention. In the figure, a hydraulic power source 1 includes an electric motor 2. As shown in FIG.

The electric motor 2 is controlled to start and stop by a start controller 3. Reference numeral 4 denotes a hydraulic pump, which is driven by an electric motor 2 to suck hydraulic oil in a hydraulic tank 6 through a suction filter 5, raise the pressure to a high pressure, and transfer the pressure oil from a high-pressure pipe 7 to a load 8 through a line filter 7a. supply to.

The upper limit of the hydraulic oil supply pressure at this time is controlled by the unload relief valve 9. The above is the general configuration of a hydraulic power source. The hydraulic fluid that has done work by driving a load 8 consisting of, for example, a hydraulic motor and a device controlled by a control valve is recovered into the hydraulic tank 6 via a low-pressure return line 10.
A flow detector 11 is installed in the middle of the return pipe 10. As shown in FIG. 2, this flow detector 11 includes, for example, a movable piece 11a that is movably attached to the end face of the low-pressure side return pipe 10 that opens to the hydraulic tank 6 so as to close the pipe. When the hydraulic oil is collected into the hydraulic tank 6 through the pipe line 10, the presence or absence of flow can be detected from the displacement of the movable piece 11a. To simplify the explanation, it is assumed that the flow detector 11 is configured to generate a signal a when there is an L flow, and not to generate a signal a when there is no flow. Returning to FIG. 1, reference numeral 12 denotes a manual operating device, which is used by the driver to switch the hydraulic circuit between on-load and unload states. When the manual operating device 12 switches to the on-road state, the signal b
occurs, and the solenoid valve 9a that controls the unload relief valve 9 is activated. As a result, the unload relief valve 9, which bypasses the hydraulic tank 6 and collects all the hydraulic oil to be discharged to the hydraulic pump 4 without increasing the pressure when the signal b is not generated, is activated to discharge by the signal b. Operates to increase oil pressure to the set upper limit. When the manual operation device 12 is switched to the fan load state,
The signal b disappears, the solenoid valve 9a returns to its original state, and the unload relief valve 9 again recovers the hydraulic fluid discharged from the hydraulic pump 4 into the hydraulic tank 6 without doing any work. The unload relief valve 9 is normally used to save power when the hydraulic system is intermittently operated, but it can be omitted from the circuit configuration when the hydraulic system is used continuously. On the other hand, the signal a of the flow detector 11 is transmitted to the signal amplifier 13.
The signal a' is amplified by the signal a' and transmitted to the signal comparator 14. The signal b of the manual operating device 12 is similarly transmitted to the signal comparator 14, and the comparator 14 determines from the signals a' and b that there is no hydraulic oil in the pipe line 10 when the hydraulic circuit is on-load. A state where there is no flow is determined, and when such a state occurs, a signal c is generated. 15 is a control discriminator;
This control discriminator 15 determines whether the state of the control valve inside the load 8 is such that hydraulic oil is allowed to flow through the pipes 7 and 1, and when the hydraulic oil is also in a state where it should flow, a signal is sent. generate d.

That is, when considering a device that controls the angle of a rotating body as the load 8, if there is an input signal to a control valve, such as a servo valve, and the valve is open, the hydraulic pump 4 is connected to the pipes 7 and 10. It is determined that the discharged hydraulic oil is about to be flushed. In addition, the hydraulic motor cannot rotate even when the rotating body hits the stopper and the control valve is engaged, and as a result, all the hydraulic fluid discharged by the hydraulic pump 4 is collected into the hydraulic tank 6 via the unload relief valve 9 in the on-load state. In such a case, it is determined that the hydraulic oil cannot flow through the pipe 10, and the generation of the signal d is stopped.
Reference numeral 16 denotes an emergency stop discriminator, which determines whether or not the hydraulic power source 1 can be stopped in an emergency based on signals c and d, and generates a signal e when stopping is required.

That is, it is detected that the hydraulic circuit is in an on-load state, the load 8 is in a state where the device should be operated by receiving a supply of high-pressure hydraulic oil, and at this time, there is no flow of hydraulic oil in the return pipe 10. to decide. If all of the above conditions are met, a rupture accident has occurred in the high-pressure side pipe 7, the low-pressure side pipe 10, or a part of the oil line between them, and the hydraulic oil has leaked to the outside. means. Therefore, in such a state, the signal e activates the start controller 3 of the electric motor 2 to stop the electric motor 2. Note that although the above example uses a method of stopping the electric motor 2 to cut off the supply of hydraulic oil, it is also possible to install a control valve in the outlet pipe of the hydraulic power source,
It is also possible to use a method in which the supply of hydraulic pressure from the hydraulic source is stopped in response to the signal e from the emergency stop discriminator 16, and the pressure oil is directly recovered into the hydraulic tank 6 via the control valve.

Also, activate the alarm using signal e or signal c,
It may also be possible to notify the driver of the danger. As detailed above, when the shape and operation of a hydraulic device such as a multi-degree-of-freedom manipulator becomes complicated, there is a high risk that the plumbing hose will become entangled with members or external objects and break. Since circuit breakage is automatically detected, the hydraulic power source can be quickly stopped without waiting for the driver's decision, making the equipment safer and preventing oil from contaminating the surrounding area.

Furthermore, the driver's monitoring work becomes easier, and work efficiency can be improved.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the configuration of an example of the device of the present invention, and FIG. 2 is a diagram showing an example of a flow detector used in the device of the present invention. 1... Hydraulic source, 3... Starting controller, 4...
...Hydraulic pump, 8...Load, 9...
Unload relief valve, 10...Return pipe line, 1
1...Flow detector, 12...Manual operator, 14...Comparator, 15...Control judger, 16... Emergency stop discriminator. Sei 1 East 2

Claims (1)

[Claims] 1. A bypass circuit is provided in which pressure fluid from a hydraulic pump driven by an electric motor is supplied to a load through a high-pressure pipe, and return fluid from the load is discharged to a tank through a return pipe, and a relief valve is provided in the high-pressure pipe. In the connected hydraulic circuit system, a flow detector is provided in the return pipe to detect the flow of fluid in the pipe, and the relief valve is operated to load and unload the hydraulic circuit system. a comparator that outputs a signal based on the flow signal from the flow detector and the on-load signal from the manual controller; and a control discriminator that is connected to the load and detects the operation of the load. and an emergency stop discriminator that outputs a stop signal to the electric motor based on the load operation signal from the control discriminator and the signal from the comparator.