JPH01204101A - Safety device used for apparatus having conducting member and method of changing at least one of attitude and height of the member near power line - Google Patents

Abstract

PURPOSE: To warn an operator that a rig is in a dangerous state and prevent a conductive device from touching the electric power line by mistake by stopping at least one of the attitude and height of the conductive member from varying when the intensity of an electric field detected by a sensor fitted to the conductive member is larger than a specific value. CONSTITUTION: When a delic approaches the electric power line, an electric field produced around the electric power line induces a voltage corresponding to the intensity of the electric field in sensors 7-7n, and signals having an amplitude corresponding to the induced voltage are supplied to a multiplexer 14, which supplies their multiplexed signal to a narrow-band-pass filter and an amplifier 17. With a signal of higher than a specific safety level, the operation of an actuator means 32 is stopped, a braking machine actuator means 44 stops the movement of the delic, and an alarm 48 warns that the delic is approaching the electric power line. Consequently, the fatal accident that the delic touches the electric power line can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a safety device and a safety method, and more particularly to a safety device and method for use in conductive members used when power lines are present. It concerns safety methods.

[Summary of the invention]

According to the present invention, there is provided a safety device for use in a device that has a conductive member to which at least one sensor is attached, and that changes at least one of the posture and height of the conductive member during operation; A safety method is provided. Sensor No. 7 detects the electric field and generates a signal representing the strength of the electric field. Further changes in attitude and height of the conductive member are prevented in response to a signal from the sensor when the electric field strength is greater than a predetermined safety value.

Drilling and oil well maintenance workers raise the derricks and masts of drilling and workover rigs, and those derricks and masts are powered! (Fatal accidents have occurred when touching or approaching power lines. Safety issues are not unique to the oil industry;
equipment such as cherry bickers used by arborists and tree surgeons, or other industries where accidents occur where construction hoists and other conductive masts or devices accidentally contact power lines. It also exists in The device of the present invention is not limited to truck-mounted devices, but can also be applied in situations where electrically conductive members are raised when power lines are present. A conductive member for the purposes of the present invention is any member that is conductive or non-conductive in structure but has other conductive means such as wires and cables. The present invention provides a method to prevent this type of accident while alerting personnel that a rig is in a dangerous situation.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to the drawings.

Reference is first made to FIG. 1 in which a typical working conductive member, such as a derrick 3, is shown mounted on a truck 1 and raised to a working position by conventional means. One or more sensors, designated sensors 7.7A, 7n, are mounted at strategic points on the derrick 3. Those sensors are electrically connected to electronic device 10 . When the derrick 3 is raised and approaches power lines during normal operation, a voltage is induced in the sensors 7 to 7n by the electric field υ generated by those power lines, and a signal corresponding to the voltage is sent to the electronic device 10. given to. When the electric field strength exceeds a predetermined value, the electronic device 10 stops the derrick from rising and issues an acoustic and optical υ alarm as described below.

Refer now to FIG. When an electric field is present, sensor 7
= in provides the signal to the multiplexer 14 of the electronic bag &10. The multiplexer 14 multiplexes the applied signals every sampling period of about 1 second. The multiplexed signals are provided to a narrow band filter and amplifier 17. The narrow band filter and amplifier 17 filters the multiplexed signal so that only signals having frequencies approximately corresponding to the frequency of the power supplied by the power line are provided to the highest signal level detection circuit 23. The highest signal level detection circuit 23 is conventional and its details are not necessary for an understanding of the invention. Maximum signal level detection circuit 2
3 can stop the operation by an override signal from the override controller 25. The override controller 25 can be constituted by a simple open/close switch that receives a DC voltage and supplies the DC voltage to the highest signal level detection circuit 23.

In order to adjust the sensitivity of the highest signal level detection circuit 23, a sensitivity control signal generator 28 sends a signal to the highest signal level detection circuit 23.
give to Maximum signal level detection circuit 23 provides a braking signal to actuator means 32. The actuator means 32 is part of a conventional lifting means and the derrick 3
It also receives a hoist enable signal from the hoist enable signal means 37 when the hoist is being raised. The brake signal from actuator means 32 is provided to brake actuator means 44 and alarm 48. The alarm 48 emits an alarm at least one of an audible and/or optical alarm.

Next, the operation of the safety device of the present invention will be explained.

An operator desiring to raise the derrick 3 causes the hoist enable signal means 3T to supply a hoist enable signal to the actuator means 32 for raising the derrick 3. When the derrick 3 approaches a power line, the electric field generated around the power line induces a voltage in the sensor 7 to In that corresponds to the strength of the electric field, and multiplexes a signal having an amplitude corresponding to the induced voltage. The liquid is supplied to the container 14. Multiplexer 14 then provides the multiplexed signal to narrowband filter and amplifier 1T. The narrowband filter and amplifier 1T that received the multiplexed signal provides the filtered signal to the highest signal level detection circuit 23. Any one of the sensors T to In that produces a signal above a predetermined safety level causes the highest signal level detection circuit 23 to give a signal to the actuator means 32 to stop the operation of the actuator means 32 and to cause the actuator means 32 to control. A brake signal is provided to the motive actuator means 44 and alarm 48. The brake actuator means 44 then stops the movement of the derrick 3 and the alarm 48 warns that the derrick 3 is approaching the power line. If any one of the sensors 7 = 7n generates such a signal, and the operator determines that derrick 3 can be safely raised without contacting the power lines, then the operator An override signal is given to the highest signal level detection circuit 23 using a controller. The maximum signal level detection circuit is then deactivated allowing the actuator means 32 to continue raising the derrick 3. The operator also uses the override signal to lower the derrick 3 after it enters a strong electric field.

Although the above description relates to an example in which the apparatus of the present invention utilizes a large number of sensors, it is also possible to use a single sensor mounted at a suitable front location on the derrick 3. In that case, the multiplexer 14 is not needed and the signal from one sensor can be applied directly to the narrowband filter and amplifier 1T.

Although FIGS. 3A, 3B, 3C, and 3D show sensor T with different structures, the structure of sensor T is not limited to the structure shown in those figures. The sensor may have any structure as long as it generates a signal representing the strength of the electric field when placed in the electric field.

The present invention described above has the advantage that the derrick is lifted from one position to another during operation, and there is a risk of contact with power lines while the derrick is in operation, which could injure or kill the operator of the derrick. Safety devices for use in derricks or equipment using electrically conductive structures that may be used for safety purposes.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a truck-mounted derrick having the safety device of the present invention, FIG. 2 is a block diagram of the safety device shown in FIG. 1, and FIGS. 3A to 3D are used in the safety device of the present invention. 1 is a schematic diagram illustrating the various possible constructions; 7, TAI7n...sensor, 14**se multiplexer, 17--...narrowband filter and amplifier, 23-
... Maximum signal level detection circuit, 25. Fist... Override controller, 28... Sensitivity control signal device, 32. Fist... Actuator means, 37.. Hoist enable signal means, 44-. - Brake actuator means, 48.0... Alarm. Patent Applicant: Texaco Development Corporation

Claims (8)

[Claims] (1) In a safety device used in a device that has a conductive member (3) and changes at least one of the posture and height of the conductive member during operation, detects an electric field and expresses the strength of the electric field. a sensor (7) attached to the conductive member (3) to generate a signal; and a sensor (7) connected to the sensor (7) to generate a signal from the sensor (7) when the strength of the detected electric field is greater than a predetermined value. blocking means (23, 32,
44) A safety device used in a device having a conductive member, characterized by comprising: (2) In the safety device according to claim 1, the sensor (7)
characterized in that it has at least one sensor, the electric field induces a voltage in the sensor with an amplitude corresponding to its strength, and said sensor (7) generates the induced voltage as said signal. safety equipment. (3) A safety device according to claim 1 or 2, in which one end of the conductive member (3) is in a fixed position and the other end can be raised to a higher level and lowered from that higher level. Safety device, characterized in that said sensor (7) is attached to said electrically conductive member (3) at or near the movable end of the electrically conductive member. (4) A safety device as claimed in claim 3, comprising actuator means (32) for moving the conductive member (3) to change the attitude of the conductive member (3) in response to a hoist signal; and hoist enable means (37) for providing a hoist signal to the actuator means in response to activation by the actuator means. a maximum signal level which provides a control signal to the actuator means when the signal from this sensor exceeds a predetermined level so as to prevent movement of the conductive member (3) and cause the actuator means (32) to provide a braking signal; Detection means (23)
and brake actuator means (44) for braking the movement of the electrically conductive member (3) in response to a brake signal from the actuator means (32) so as to prevent further changes in said attitude. A safety device characterized by: (5) A safety device according to claim 4, wherein the blocking means (23, 32, 44) are adapted to filter the signal from the sensor (7) so as to obtain a signal having a frequency approximately corresponding to the frequency of the electric field. sensor and highest signal level detection means (
Safety device characterized in that it further comprises a filter (17) connected between (23). (6) A safety device according to claim 5, wherein the actuator means (32) is connected to the actuator means (32) for providing an alarm to the operator of the device in response to the braking signal, and for providing an electrically conductive electric field having a strength greater than a predetermined safety value. A safety device further comprising an alarm (48) that warns an operator that the member (3) has entered. (7) providing at least one sensor at or near the conductive member that generates a signal representative of the strength of the electric field when the electric field is present; moving the conductive member until at least one of the heights is reached or until the sensor generates a signal indicating that the conductive member has entered an electric field having a strength greater than a predetermined safe value; A method for safely changing at least one of the attitude and height of a conductive member near a power line, comprising: (8) In a safety device used in a device that has a conductive member (3) and changes at least one of the posture and height of the conductive member during operation, detects an electric field and indicates the strength of the electric field. A sensor (7) attached to the conductive member (3) for generating a signal, and a sensor (7) connected to the conductive member (3) when the conductive member (3) enters an electric field having a strength higher than a predetermined safety value. An alarm device (23, 32, 4) that sometimes issues an alarm in response to a signal from a sensor
4) A safety device for use in a device having a conductive member, characterized by comprising: