JPH0450607A - Method for measuring extension of pipe line - Google Patents

Abstract

PURPOSE:To measure not only the shortest extension but also an extension of another path by transmitting a second sound while reception following first reception of a first sound, for example second reception, is being noticed. CONSTITUTION:First, a transmitter/receiver 2 at a measurement starting point A supplies a first sound f1 into a pipe 1 and this is received by a transmitter/ receiver 3 at a measurement ending point B. Then at the measurement ending point B, the transmitter/receiver 3 supplies a second sound f2 into the pipe 1 a constant time period after the first sound f1 was first received by the transmitter/receiver 3, and this is received by the transmitter/receiver 2 at the measurement starting point A. When the second sound f2 is received at the measurement starting point A, an extension of the pipe is calculated by the following equation based on time required from transmission of the first sound f1 until the reception of the second sound f2 at the measurement starting point A, time required from the reception of the first sound f1 until transmission of the second sound f2 at the measurement ending point B and sound speed in fluid flowing in the pipe (gas in this case).

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for measuring the length of a pipe, such as a gas pipe, a water pipe, etc.

(Conventional technology) Conventionally, underground pipes such as gas pipes and water pipes are not exposed, so there are limited methods for directly measuring the length of the wire, such as pushing a wire inside the pipe and measuring the length of the wire. Two methods have been adopted: one method is to measure the length of a lightweight string by passing it through the pipe using the force of the wind.

(Problem to be solved by the invention) However, if the underground pipe is a gas pipe, the former method requires a special jig to prevent the gas inside the pipe from coming out. In the latter method, the gas inside must be discharged to the outside before the work is carried out.

The present invention has been made in view of the above-mentioned problems of the prior art, and its purpose is to eliminate the internal gas from being discharged.
Furthermore, the present invention aims to provide a method that can easily measure the length of a buried pipe without using any special jig.

(Means for Solving the Problems) In order to achieve the above object, in the buried pipe extension measurement method of the present invention, a first sound is emitted and flows into the pipe from the measurement start point of the pipe, and at the measurement end point. After receiving the first sound, a second sound is emitted and flows into the pipe from the end point, the second sound is received at the start point, and the first sound is received at the measurement start point.
From the time required from transmitting the sound to receiving the second sound, and the time required from receiving the first sound to transmitting the second sound at the end point, the starting point is determined. , the average round trip time required for the sound to propagate between the end points is determined, and the length of the pipeline is determined based on this average time and the speed of sound in the fluid flowing within the pipeline.

(Function) According to the pipe length measurement method of the present invention configured as described above, the sound transmitting and receiving part into the pipe is composed of a microphone and a speaker. By attaching the tube through the tube and opening the valve during measurement, the length of the tube can be measured without releasing the gas inside the tube.

(Example) Hereinafter, an example of implementation of the present invention will be described based on the drawings.

1 in the figure is an underground pipe such as a gas pipe, for example, from a desired point A (hereinafter referred to as measurement start point A) to a desired position B (hereinafter referred to as measurement end point B) of the buried pipe 1. When trying to measure the length of a pipe, the transmitter/receiver devices 2 and 3 are installed at the measurement start point A and the measurement end point B, respectively, and first, the first sound f1 flows into the pipe 1 by the transmitter/receiver device 2 at the measurement start point A. This is received by the transmitting/receiving device 3 at the measurement end point B.

Subsequently, at the measurement end point B, after a certain period of time from when the transmitting/receiving device 3 first receives the first sound f1, the transmitting/receiving device 3 causes a second sound f2 to flow into the pipe 1, and this is transferred to the measurement starting point. A's transmitting/receiving device 2 receives it.

When the second sound f2 is first received at the measurement starting point A,
The time required from the transmission of the first sound f1 to the reception of the second sound f2 at the measurement start point A, the time required from the reception of the first sound f1 to the transmission of the second sound f2 at the measurement end point B, the tube 1 The length of the pipe is calculated using the following formula based on the speed of sound in the fluid (gas in this case) flowing inside.

T = tr + t 2 + t 3A = v@t tl + j2: Time required for sound to propagate in the pipe (round trip) t3; The time T required to emit the second sound f2; from the time the first sound f was emitted at the measurement starting point A to the second sound f2;
time t required to receive the sound f2; average V of the round trip time required for the sound to propagate in the pipe; sound speed l in the fluid in the pipe; extension of the pipe; and the measurement starting point. The transmitting/receiving device 2 at location A includes, for example, a conventionally known oscillating section 2a, a transmitting and receiving amplifier section 2b, a 2CN input detection section 2d, a speaker 2! , a microphone 2 (etc.), and a timer 21i that counts the time from the transmission of the first sound f1 to the reception of the second sound f2.
, a calculation section 2h that calculates the pipeline extension using the above-mentioned calculation formula, a display section 2j that displays the value calculated by the calculation section 2h, etc., and the transmitting/receiving device 3 at the measurement end point B is connected to the starting point A.
Similar to the transmitting/receiving device 2, it includes an oscillating section 3a, a transmitting and receiving amplifier section 3b, a 3cs input input section 8tl, a speaker 3e,
In addition to being equipped with a microphone 31 etc., for example, the first sound f1
Timer 3g that counts time from reception, first sound f1
It is provided with a control section 3j, etc., which activates the oscillating section 3a and modulates the frequency after a predetermined period of time has elapsed from reception.

These transmitting/receiving devices 2.3 are attached to the pipe 1 via valves 4.5 at a measurement start point A and a measurement end point B, respectively.

The valve 4.5 is opened only during measurement.

In the embodiment described above, the first
A second sound is emitted a predetermined time after the first sound f1 is received, and the second sound is also emitted at the measurement starting point A.
The round-trip propagation velocity between the start and end points of the sound was determined based on the time when the sound f2 was first received.

The second sound f2 is transmitted based on the second reception, or the second or fourth reception, and accordingly, the second sound f2 is transmitted at the measurement starting point A for the second time. Alternatively, the time required from transmitting the first sound f1 to receiving the second sound f2 may be calculated based on the second and fourth times the sound is received. Alternatively, the time required for a round trip for specific sounds such as the first and second sounds may be determined.

By doing so, it becomes possible to measure the extension of another route in addition to the shortest route extension between the measurement start point A1 and the measurement end point 8.

For example, in Fig. 5, the first signal transmitted at measurement starting point A
Naturally, there is a time difference between when the sound f1 reaches the measurement end point B via the shortest route a and when it reaches the measurement end point B via a second route other than the shortest route a. At the end point B, f□ that has come via the shortest route a is first received, and then, with a slight time delay, fl that has come via the second route is received again.

Therefore, at the measurement end point B, the second sound f is emitted twice after a predetermined period of time after receiving the first sound f1 emitted at the measurement start point A.
- At the force measurement starting point A, the second sound f2 transmitted twice at the measurement end point B is received, and when the first f2 is received and the second f2 is If we calculate the time from transmitting the first sound f□ to receiving the second sound f2 for each of the two degrees received, we can find the shortest route between the measurement start point A1 and the measurement end point 8. The extension of a and the extension of the second path can be measured respectively.

(Effects) Since the present invention is constructed as described above, the following effects can be achieved.

(1) A speaker that allows sound to flow into the pipe and a microphone that receives the sound propagated inside the pipe are attached to the pipe via a valve, and the valve is opened during measurement to release the fluid inside the pipe to the outside. The length of the conduit can be measured without

(2) The propagation speed of sound varies depending on the flow of fluid in the pipe, but by calculating the average round trip propagation time, the influence of the flow of fluid in the pipe is canceled out, so even if there is a flow velocity in the pipe, the sound propagation speed changes over time. If the fluctuations are small, the pipe length can be measured.

(3) In addition to emitting the second sound based on the first reception of the first sound at the measurement end point, we also pay attention to the reception after the first reception of the first sound, for example, the second reception. second
In addition to the shortest extension, by transmitting the sound of
Other path lengths can also be measured.

[Brief explanation of drawings]

Fig. 1 is a conceptual diagram of a pipe length measurement method showing an embodiment of the present invention, Fig. 2 is a functional block diagram showing an example of a transmitting/receiving device installed at a starting point position, and Fig. 3 is a transmitting/receiving device installed at an end point position. FIG. 4 is a functional block diagram showing an example of the device, FIG. 4 is a time chart, and FIG. 5 is a conceptual diagram when measuring the extensions of the shortest route and the second route. A: Measurement start point B: Measurement end point 1: Pipe

Claims (1)

[Claims] A first sound is emitted and flowed into the pipe from the measurement start point of the pipe, and after the first sound is received at the measurement end point, a second sound is emitted and flowed into the pipe from the end point. The time required to receive the sound at the above-mentioned starting point, emit the first sound at the measurement start point and receive the second sound, and the time required to receive the second sound after receiving the first sound at the end point. 2. A method for measuring the length of a pipe line, characterized in that the length of the pipe line is determined based on the time required to emit the sound and the speed of sound in the fluid flowing in the pipe line.