JPS62280486A - Drilling overload preventing control method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a defense excavation method, and particularly to a method for protecting the excavation equipment from overload when the excavation load becomes overload. The present invention relates to a control method for preventing overload of excavation.

[Conventional technology] When drilling a defense such as an offshore oil drilling rig, an offshore mineral resources drilling rig, or an onshore oil drilling rig, the drilling bit is rotated and the drilling bit uses its own weight to descend and drill the defense. I'm digging.

In this resistance excavation, the underground layers are not uniform in the excavation direction, and therefore the rotational load on the excavation bit varies depending on the strata.

Conventionally, the rotary machine internal combustion engine or electric motor was used to drive the drilling bit, and the load on the internal combustion engine or electric motor was manually adjusted by checking a torque meter or the like.

[Problems to be solved by the invention] However, since it is manual, the load cannot be adjusted accurately, and if an instantaneous overload occurs during excavation, the internal combustion engine for the rotary machine will stop due to the overload, and the excavation pit will be shut down. There is a problem in that it is not possible to prevent excessive wear of the drill pipe or bending of the drill pipe.

The present invention has been made in consideration of the above circumstances, and is an excavator capable of protecting the rotational drive means, the excavation bit, etc. from overload when the rotational load becomes overload when the excavation bit is rotationally driven. The purpose is to provide an overload prevention control method.

[Means and Effects for Solving the Problems 1] In order to achieve the above object, the present invention rotates a drilling bit with an internal combustion engine for a rotary machine and makes the drilling bit move downward by a digging drive means. In this method, the shaft torque of the internal combustion engine for the rotary machine is detected, and when the shaft torque reaches a set maximum value, the digging drive means stops the descent of the digging bit. , the shaft torque of the internal combustion engine for the rotary machine is detected, and when the shaft torque reaches the set maximum value, it is considered an overload and the digging driving means is stopped, the digging bit stops descending, and in this state, the rotary machine When the shaft torque of the internal combustion engine for the machine becomes small, the excavation drive means is driven again to cause the excavation drive to descend, thereby protecting the internal combustion engine for the rotary machine and the excavation bit from overload.

[Embodiments] Hereinafter, preferred embodiments of the excavation overload prevention control method according to the present invention will be described based on the accompanying drawings.

FIG. 1 shows an apparatus for carrying out the method of the present invention, in which 1 is a tower, which is installed on the ground 2 to be excavated.

A drill vibrator 3 is provided on the tower 1 so as to be movable up and down, and a drilling bit 4 is attached to the tip thereof. A wire 5 is connected to the upper end of the drill vibe 3, and the wire 5
It is hung on a pulley 6 provided at the top of the cypress 1 and is also wound around a drum 8 of an AC motor 7 for draw works, which is an excavation drive device.

Inside the tower 1, an internal combustion engine 9 for a rotary machine, which is a rotary drive means for rotating a drilling bit 4 via a drill vibrator 3, is provided. The drill vibrator 3 is rotated via the gear 11, and the drilling bit 4 is rotationally driven.

Shaft torque is detected by the overload control circuit 12 as a load of the internal combustion engine 9 for the rotary machine, and when the shaft torque reaches a set maximum value, a stop signal 13 is output to stop the rotation of the AC motor 7 for the draw works. It looks like this.

This overload control circuit 12 includes a shaft torque-current converter 15 that detects the shaft torque of the internal combustion engine 9 for a rotary machine and outputs a load current proportional to this shaft torque, and the shaft torque-current converter 15. and a set maximum load current value, and outputs a stop signal 13 when the load N current value exceeds the set value.

Next, this overload control circuit 12 will be explained in detail with reference to FIG.

The load current value outputted from the shaft torque-current converter 15 is a value proportional to the shaft torque of the internal combustion engine 9 for the rotary machine, and this current value is sent to the subtractor 18 by the resistor 17 as a voltage value input signal a. is input.

A current reference device 19 consisting of a variable resistor connected to a positive power source is connected to the subtracter 18, and a current reference voltage signal corresponding to the load current value at the rated load state of the internal combustion engine 9 for the rotary machine is preliminarily connected. It is input to the subtracter 18. Subtractor 1
8 is a signal a output from the shaft torque-current converter 15
A signal C corresponding to the overload current of the internal combustion engine 8m@9 for the rotary machine is outputted to the integrator 20 by subtracting the current reference signal S set by the R flow reference device 19.

The integrator 20 integrates the voltage signal corresponding to the overload current if the overload state of the internal combustion engine 9 for the rotary machine continues, and decreases the voltage signal by that amount if the load becomes below the rated load.
The output signal d is input to the upper limit comparator 21.

An upper limit reference device 22 such as a variable resistor connected to a positive power source is connected to the upper limit comparator 21, and the upper limit reference device 22 corresponds to a preset overload capacity of the internal combustion engine 9 for the rotary machine. The upper limit reference voltage signal (set maximum load signal) e is input to the upper limit comparator 21. Upper limit comparator 2
1, the signal d from the integrator 20 is the upper limit reference voltage signal e
When it is larger, a signal f is sent to excite the third relay coil 23, and the third relay contact 24 thereof is closed.

On the other hand, the power line 25 of the AC motor 7 for draw works
A first relay contact for overload prevention (B contact) 26 and a second relay contact for activation (A contact) 27 are connected in series, and a first relay contact for activating the first relay contact for overload prevention 26 is connected in series.
The third relay coil 28 is opened and closed by the upper limit comparator 21.
A second relay coil 30 that is connected in series with the relay contact 24 to the control power source 29 and that operates the second starting relay contact 27 is connected to the control power source 2 in series with the push button switch 31.
Connected to 9. Further, an auxiliary second relay contact 32 for self-holding the second relay contact 27 is connected in parallel to the push button switch 31.

In the above, as shown in FIG. 1, the drilling bit 4 is
It is rotated by an internal combustion engine 9 for a rotary machine, which is a rotational driving means, and at the same time, the wire 5 is paid out from an AC motor 7 for a drawworks, which is an excavation driving means, and its drum 8, and the wire 5 is dug downward.

When the shaft torque of the internal combustion engine 9 for the rotary machine is detected by the shaft torque-current converter 15 of the overload 11 control circuit 12 during excavation of this defense valve, and the detected value reaches the set maximum value indicating an overload, The overload detection circuit 16 outputs a stop signal 13 to the draw works AC motor 7, and the rotation of the motor 117 is stopped. As a result, the feeding of the wire 5 is stopped, and the drilling bit 4 rotates while substantially stopping at the digging position. Note that when this AC electric motor 117 for drawworks is stopped, the tank movement 1117 can rotate freely, but the wire 5 is not fed out by a speed reduction device from the electric motor to the drum 8, or by a reverse rotation prevention device built into the drum 8. is now suspended.

Thereafter, when the shaft torque of the rotary machine internal combustion engine 9 decreases, the overload prevention control circuit 12 sends a stop signal 13
is released, the draw works AC motor 7 is started again, and the digging bit 4 is allowed to descend.

This will be explained in detail with reference to signal waveform diagrams in FIGS. 2 and 3.

FIG. 3 shows each signal a of the overload control circuit 12 shown in FIG.
-f shows each voltage waveform change.

First, the internal combustion engine 9 for the rotary machine is started, and when the push button switch 31 is pressed, the second relay coil 30 for starting is energized, its second relay contact 27 is closed, and the AC electric motor 117 for the draw works is activated. will be activated.

In this case, the auxiliary second relay contact 32 is also closed at the same time, so even if the pushbutton switch 31 is opened, the second relay coil 30 remains energized, and its second relay contact 27 remains closed. has been done. In order to manually stop the draw works AC motor 7, a push button switch (not shown) is pressed to open the second relay contact 27.

In this way, the internal combustion engine 9 for the rotary machine and the AC power supply for the drawworks! ! When the l1 machine 7 is driven, the excavation bit 4 descends and excavates the defense valve.

During this excavation, a signal a proportional to the shaft torque of the internal combustion engine 9 for the rotary machine is output from the shaft torque-current converter 15, and the signal from the current reference device 19 is subtracted by the subtractor 18.

For example, if the input signal a changes as shown in the graph (△) in Figure 3, and the signal a is subtracted from the reference signal, the output signal C of the subtractor 18 will be as shown in the graph (B). It becomes like this.

The signal d obtained by integrating this output signal C by the integrator 20 has a voltage waveform shown in graph (C), and this is input to the upper limit comparator 21. When compared with the reference voltage signal e, when the signal d exceeds the signal e, the signal d becomes the signal e as shown in graph (D).
The signal f is output only for the time t1 exceeding .

As a result, the third relay coil 23 shown in FIG. 2 is energized, and when its third relay contact 24 is closed, the first overload prevention relay coil 28 is energized, thereby opening the first relay contact 26. The power supply to the draw works AC motor 7 is stopped from the power supply line 25, and the rotation of the motor 7 is stopped.

After this, as shown in graph (C), when the signal d from the integrator 20 becomes lower than the upper limit reference signal e, the upper limit comparator 2
1 output signal f becomes zero potential, and the third relay coil 2
3 is de-energized, the third relay contact 24 is opened, and the first relay coil 28 for overload prevention is cut off from the two control power supplies, so the first relay contact 26 is closed and the draw works AC is turned on again. Tia machine 7 will be activated.

As described above, by detecting the shaft torque of the rotary machine internal combustion engine 9 and stopping the rotation of the draw works AC motor 7 when the shaft torque reaches the set maximum value, the internal combustion engine 9 for the rotary machine The drilling bit 4 can be protected from overload.

Note that a circuit 41 as shown in FIG. 4 can also be used as the overload detection circuit 16. That is, the load current output from the shaft torque-current converter 15 is A/D':]
After the signal is converted into a digital signal by an inverter 42, it is input to a computer 43. The computer 43 stores in advance a current reference value input from the keyboard 44 and an upper limit reference value corresponding to the overload capacity of the internal combustion engine 9 for the rotary machine, and a digital signal input from the A/D converter 42. is subtracted by the current reference value and then integrated, and the magnitude relationship between the integrated value and the upper limit reference value is compared. As a result of the comparison, only when the integral value exceeds the upper limit reference value, the computer 43 outputs the control signal 45 and the contact 46 is opened, thereby stopping the power supply to the AC motor 7 for draw works, and the electric power! ! 17 is stopped. Further, when the integral value becomes equal to or less than the upper limit reference value, the output of the control signal 45 from the computer 43 is stopped, the contact 46 returns to the open state, and the draw works AC motor 7 is started again. Note that the current reference value and upper limit reference value inputted to the computer 43 from the keyboard 44 are displayed on the CRT 47, so that they can be checked at any time.

[Effects of the Invention] As is clear from the detailed description above, the present invention exhibits the following excellent effects.

(1) The shaft torque of the internal combustion engine for the rotary machine that rotates the drilling bit is detected, and when the shaft torque reaches the maximum setting value, the digging drive means stops lowering the drilling bit. Overload of the internal combustion engine for the rotary machine can be automatically prevented.

(D) Since overload of the internal combustion engine for the rotary machine can be prevented, excessive wear of the drilling bit can be prevented and bending of the drill pipe can also be prevented.

(3) Efficient excavation can be achieved and safety is improved through automation.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing an example of a device implementing the method of the present invention, Fig. 2 is a detailed diagram of the overload control circuit of Fig. 1, and Fig. 3 is a voltage waveform of each signal in the circuit of Fig. 2. 4 are configuration diagrams showing other examples of the overload control circuit. In the figure, 4 is an excavation bit, 7 is an AC motor for draw works which is an excavation drive means, 9 is an internal combustion engine for a rotary machine, and 12 is an overload control circuit. 4: Drilling bit 7: Diagram 1 for draw works

Claims (1)

[Claims] In a method of excavating a defense by rotating an excavation bit with an internal combustion engine for a rotary machine and moving the excavation bit downward with an excavation drive means, the shaft torque of the internal combustion engine for a rotary machine is detected, and the shaft torque is An excavation overload prevention control method characterized in that the excavation drive means stops the descent of the excavation bit when the set maximum value is reached.