JPH03185388A - Method for detecting branch part of embedded piping - Google Patents

Abstract

PURPOSE:To accurately detect the position of the connection part of a branched metal pipe by investigating a measuring range where a voltage or current measured value largely changes or an electric resistance value largely changes. CONSTITUTION:Electrode rods 8 are used as detecting electrode rods 8B and the voltage or current value between a pair of the detecting electrode rods 8B is measured. This voltage or current measuring process is executed two or more times in such a state that a measuring range is altered in the longitudinal direction of an embedded metal pipe 1. From the voltage or current values obtained in the voltage or current measuring process executed two or more times or the voltage or current measured values, it is judged where the connection part 13 of a branched metal pipe 12 is present in the longitudinal direction of the embedded metal pipe 1 on the basis of the change state of the electric resistance value and measuring range calculated by a meter or operation.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention provides a method for connecting buried metal pipes for city gas, etc., even when fluid transport continues, while connecting to the buried metal pipes and leading them to the ground. The present invention relates to a method for detecting where branched metal pipes are connected.

[Conventional technology]

Conventionally, the positions of buried metal pipes and branch metal pipes have been confirmed using detectors such as pipe locators and radar locators that utilize magnetic fields from metal pipes, and the positions of the connections between these pipes have been determined.

[Problem to be solved by the invention]

However, near the joint between the two pipes, the magnetic fields generated by both pipes interact with each other, making it impossible to accurately confirm the positions of the two pipes. Excavation work required a lot of money and time.

An object of the present invention is to enable accurate detection of the position of a branch part of a buried pipe from the ground.

[Means to solve the problem]

The characteristic means of the present invention is to bring a power electrode rod inserted into the ground from the ground surface into contact with a buried metal pipe, and to connect a branch metal pipe that is connected to the buried metal pipe and led out to the ground, and to connect a power source to the power electrode rod. connecting the detection electrode rods inserted into the ground from the ground surface to the buried metal pipe, and the voltage value between the pair of detection electrode rods that are in contact with each other at two points in the longitudinal direction of the buried metal pipe. or measuring the amount of current, performing the voltage or current measurement process multiple times with the measurement range changed in the longitudinal direction of the buried metal, and measuring the voltage or current obtained in the multiple voltage or current measurement processes. or the state of change in the electrical resistance value determined from the measured voltage or current values, and the measurement range, in which direction in the longitudinal direction of the buried metal pipe the connection part of the branch metal pipe exists. Its purpose is to determine the following:

[For production]

When a power supply electrode is connected to the buried metal pipe, a power source is connected to the branch metal pipe and the power supply electrode, and a pair of detection electrodes are brought into contact with the buried metal pipe, one or both of the detection electrodes However, only when there is contact between the connection part of the branch metal pipe and the contact position of the power electrode rod, the voltage value and current amount between both detection electrode parts become a certain value.

Therefore, the process of measuring the voltage value or current amount between a pair of detection electrodes is performed multiple times while changing the measurement range in the longitudinal direction of the buried metal pipe, and the voltage or current measurement value is determined in any measurement range. By checking whether there has been a large change or whether the electrical resistance value has changed significantly, the position of the connection part of the branch metal pipe can be accurately detected.

Then, you can narrow the gap between both detection electrodes to find out in more detail where the connection part of the branch metal pipe is within the detected measurement range, or By making the interval sufficiently small, the position of the connection part of the branch metal pipe can be detected within a narrow range.

〔Effect of the invention〕

As a result, we have developed a method for detecting the location of a branch part of a buried pipe that is excellent in terms of economy and workability, by accurately detecting the connection position of a branch metal pipe to a buried metal pipe, and by quickly and inexpensively digging out the connection part. I was able to establish it.

〔Example〕

An embodiment is shown in FIGS. 1 and 2.

(a) As shown in Figure 1 (a), a buried metal pipe (1
) and branch metal pipe (12) with a detector (2) such as a pipe locator or radar locator, and check the insertion position of the electrode rod in the buried metal pipe (1).
2) so that it spans both sides of the connection part (13).

(b) As shown in FIG. 1 (+1), a hole is made in the paved road (4) using a core extraction tool (3) at the insertion position of the electrode rod.

(c) As shown in Fig. 1 (c), in each drilling hole, the ground is excavated with the water jet from the nozzle (5), muddy water and pebbles are removed with the suction machine (6), and the buried metal pipe is removed. Form an underground hole (7) that reaches 1).

(d) As shown in FIG. 1(d), the electrode rod (8) inserted into the ground from the ground surface in each of the underground holes (7) is brought into contact with the buried metal pipe (1).

At this time, a meter (9) is connected to the first electrode (8a) and second electrode (8b) provided in an electrically insulated state on the electrode rod (8), and the electrode is measured by measuring voltage, current or resistance. Stick (8
) is electrically connected to the buried metal pipe (1).

If the electrode rod (8) is not electrically connected to the buried metal pipe (1) due to mackerel, etc., it may be buried by rotating or poking the electrode rod (8), or by water jetting or sandblasting. The metal tube (1) is treated to remove rust and the like, and the electrode rod (8) is electrically connected to the buried metal tube (1).

0) One end of the electrode rod (8) is used as a power electrode rod (8A), which is connected to the buried metal pipe (1), and the branch metal pipe (12) led out to the ground and the power source electrode rod (8A)
Connect a DC, pulse or AC power source (4) to the power supply.

(F) Using the other electrode rod (8) as a sensing electrode rod (8B>), measure the voltage value or current amount between the pair of sensing electrode rods (8B).

Then, the voltage or current measurement process is performed using the buried metal (1).
Execute multiple times with the measurement range changed in the longitudinal direction.

(g) Based on the voltage or current measurement values obtained in the above-mentioned multiple voltage or current measurement steps, or the state of change in the electrical resistance value determined from the voltage or current measurement values by a meter or calculation, and the measurement range. Then, it is determined in which longitudinal direction of the buried metal pipe (1) the connecting portion (13) of the branch metal pipe (12) is present.

In other words, one or both of the pair of detection electrode rods (8B) is in contact between the connection part (13) of the branch metal tube (12) and the contact position of the power supply electrode rod (88). , the voltage value and current amount between both detection electrodes (8B) will be a certain value, and both detection electrodes (8B) will connect to the connection part (1) of the branch metal tube (12).
3) and the contact position of the power supply electrode (8A), the voltage value and current amount between both detection electrodes (8B) will be zero, and as shown in Figure 2. As shown, the voltage or current measurement value changes greatly between the measurement range where the connection part (13) of the branch metal pipe (12) exists and the measurement range next to it, and the electrical resistance value also changes greatly. Therefore, it is possible to determine in which measurement range the connection part (13) of the branch metal pipe (12) exists.

[Another example]

Next, another embodiment will be described.

Insert the electrode rod (8) into the ground from the ground surface to the buried metal pipe (
The specific means for contacting 1) can be changed as appropriate. For example, by drilling an underground hole with a drill or using an electrode rod (8).
may be pushed into the ground, or the step of measuring voltage, current, etc. and the step of installing some of the sensing electrode rods (8B) may be performed simultaneously.

When performing the voltage or current measurement process multiple times, the order in which the measurements are performed can be freely selected.

The installation interval of the detection electrode rods (8) may be substantially constant or irregular, and may be wide or narrow.

If the installation interval is wide, the connection part (1) of the branch metal pipe (12)
Within the measurement range where 3) is detected, the measurement range may be further narrowed using the same method to more accurately detect the position of the connection part (13) of the branch metal pipe (12).

The buried metal pipe (1) may be for city gas, water, or any other type.

Incidentally, although reference numerals are written in the claims section for convenient comparison with the drawings, the present invention is not limited to the structure shown in the accompanying drawings.

[Brief explanation of drawings]

The drawings show embodiments of the present invention, and FIG. 1(a) or (a) is a conceptual diagram of the construction procedure, and FIG. 2 is an explanatory diagram of the branch position determination method. (1)...Buried metal pipe, (8A)...
Electrode rod for power supply, (8B)... Electrode rod for detection, (
12)...Branch metal pipe, (13)...
Connection part.

Claims (1)

[Claims] A branch metal pipe that is connected to the buried metal pipe (1) by bringing a power electrode rod (8A) inserted into the ground from the ground surface into contact with the buried metal pipe (1) and led out to the ground. (12) and the power supply electrode (8A), and the detection electrode (8B) inserted into the ground from the ground surface is brought into contact with the buried metal pipe (1), and the The voltage value or the amount of current between the pair of detection electrode rods (8B) that are in contact with each other at two locations in the longitudinal direction of the metal tube (1) is measured, and the voltage or current measurement process is performed on the buried metal (1). Changes in the voltage or current measurement values obtained in the multiple voltage or current measurement steps, or the electrical resistance values obtained from these voltage or current measurement values, performed multiple times with the measurement range changed in the longitudinal direction. Branch part detection of buried piping, which determines in which longitudinal direction of the buried metal pipe (1) the connection part (13) of the branch metal pipe (12) exists based on the state and the measurement range Law.