JP2007209891A - Method for cleaning inside of pipe - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for cleaning the inside of a pipe which can easily and effectively clean the pipe. <P>SOLUTION: A first process consisting of the step of closing a valve A and a valve B arranged on the upstream end and the downstream end of the pipe 1 respectively and a step of reducing the pressure of the pipe 1 by a vacuum pump 6 and the step of opening the valve A on the upstream end of the pipe 1, and a second process having the step of pressurizing the pipe 1 by a compressor 3 after the valve A on the upstream end is closed and a step of opening the valve B on the downstream end, are provided. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for cleaning the inside of a pipeline such as a gas pipe.

  As a method of this type, there is a technique for removing and discharging deposits attached to the inner wall surface by inserting a pig into a pipe line, feeding a fluid such as gas from one side, and pumping the pig. (For example, refer to Patent Document 1).

  Since this method requires the pressure of the fluid to pump the pig, it can be applied to a high-pressure pipe capable of flowing a high-pressure fluid, but cannot be used for a medium-pressure pipe or a low-pressure pipe. .

  Therefore, as a cleaning method that can be used with medium-pressure pipes and low-pressure pipes, a clean tank that accumulates air, nitrogen, etc. is installed upstream of the pipe to be cleaned, and the gas that has accumulated in the tank is sent to the pipe to be cleaned. There was a cleaning method called flushing, in which the pipe line was cleaned by repeating the blow.

JP 2002-192096 A

  However, the cleaning method using flushing has a problem in that the cleaning efficiency depends on the conditions (capacity and pressure) of the tank, so that depending on the tank conditions, the required number of times of flushing is increased and the cleaning efficiency is deteriorated. Moreover, since the tank used for flushing needs the same capacity or more than the pipeline to be cleaned, for example, when the pipeline to be cleaned is 2 km, a tank having a length of 2 km or more must be installed. However, it was difficult to install the tank depending on the surrounding environment. In addition, when the pipe length is extremely long, it is impossible to clean the pipe by flushing. Even if a large-capacity tank can be installed, the tank itself must be clean. Therefore, the tank itself must be cleaned prior to the cleaning of the pipeline, which requires labor and cost.

  This invention is made | formed in view of such a point, and it aims at providing the cleaning method in a pipe line which can clean a pipe line simply and efficiently.

  The method for cleaning an inside of a pipeline according to the present invention includes a step of closing valves disposed at an upstream end and a downstream end of the pipeline, a step of reducing the pressure inside the pipeline by a vacuum pump, and a valve at the upstream end of the pipeline. A first step having an opening step, a second step having a step of accumulating pressure in the pipeline by a compressor after closing the upstream end valve, and a step of opening the downstream end valve. .

  Moreover, the cleaning method in a pipeline according to the present invention repeatedly performs the first step and the second step as one cycle.

  Further, in the pipe line cleaning method according to the present invention, the cleaning target pipe line is connected to the downstream end of the cleaned pipe line that has been cleaned by the first step and the second step, and the cleaned pipe line is flushed. A third step for closing the valves at both the upstream end and the downstream end of the cleaned pipeline, and a step of accumulating pressure in the cleaned pipeline with a compressor; And a fourth step having a step of opening a valve at the downstream end of the path.

  Moreover, the cleaning method in a pipeline according to the present invention repeatedly performs the third step and the fourth step as one cycle.

  As described above, according to the present invention, an air flow is generated in the main body of the pipe by bringing the inside of the pipe into a reduced pressure state or an accumulating state using a vacuum pump or a compressor, and then setting the open state. Since the pipe main body can be directly cleaned using the above, a tank which has been conventionally required is not necessary, and the equipment for cleaning can be greatly simplified. Further, since the tank is not used, cleaning of the tank itself becomes unnecessary, and the cleaning efficiency can be improved.

Embodiment 1 FIG.
FIG. 1 is an explanatory view of the principle of cleaning in the pipe line cleaning method of the present invention.
In FIG. 1, a valve A and a valve B are installed at an upstream end (left side in the figure) and a downstream end (right side in the figure) of a pipeline 1 to be cleaned. A vacuum pump is connected so that the inside of the pipe line 1 can be decompressed and accumulated.

Hereinafter, the cleaning method in the pipe line in the system configured as described above will be described.
The in-pipe cleaning method of the present example mainly includes a first step of flushing the upstream end side in the pipe 1 and a second step of mainly flushing the downstream end side in the pipe.

  In the first step, first, (1) both the valve A and the valve B arranged on the upstream end side and the downstream end side of the pipe line 1 are fully closed, and a vacuum pump (not shown) is driven to depressurize the pipe line 1. And make negative pressure. (2) The valve A is fully opened. As a result, outside air is sucked into the pipe line 1 from the valve A side, the dust 10 in the pipe line 1 is brought closer to the downstream end side, and the upstream end side in the pipe line 1 can be mainly cleaned.

  In the second step, first, (1) both the valve A and the valve B are fully closed, a compressor (not shown) is driven, the pipe 1 is filled with pressure, and pressure is accumulated. (2) The valve B is fully opened. As a result, the gas in the pipeline 1 is diffused out of the pipeline 1 through the valve B. At this time, the dust 10 brought to the valve B side in the pipe line 1 is also diffused out of the pipe line 1 together with the gas, and the downstream end side in the pipe line 1 can be mainly cleaned. By repeatedly performing the first step and the second step as one cycle, the entire inside of the pipe line 1 can be cleaned more cleanly.

Hereinafter, a specific system to which the pipe line cleaning method of the present invention is applied will be described.
FIG. 2 is a diagram showing a construction example of a system to which the in-pipe cleaning method of the present invention is applied. FIG. 2A shows an example of system construction when performing the first step, and FIG. 2B shows an example of system construction when performing the second step. Further, the valve A1 and the valve A2 in FIG. 2 correspond to the valve A in FIG. 1, and the valve B corresponds to the valve B in FIG. FIG. 2 shows an example in which a gas pipe embedded in the ground is to be cleaned. In the example of FIG. 2, the left side in the figure is the upstream end side of the flushing, and the right side in the figure is the downstream end side.

  The upstream end and the downstream end of the pipe line 1 are exposed from the excavation portion 20 excavated in the ground, and can be connected to temporary pipes 2, 5, and 7 described later. Further, both end faces 1a and 1b of the pipe line 1 are closed. A valve A1 and a valve A2 are provided on the upstream end side of the pipe line 1, and a compressor unit 3 having a compressor 3a and a dehumidifier 3b is connected to the valve A1 via a temporary pipe 2. . The valve A2 is connected to a temporary pipe 4 that communicates with the atmosphere, and the opening or closing of the atmosphere can be switched by opening and closing the valve A2. Further, a vacuum pump 6 is further connected to the upstream end side of the pipe line 1 through a drawing pipe 5 and a valve C. In addition, in the system of the 2nd process shown to FIG. 2 (B), although the vacuum pump 6 is removed, of course, you may install as it is, without removing.

  Further, a temporary pipe 7 and a silencer 8 are connected to the downstream end side of the pipe line 1, and a valve B is connected to the temporary pipe 7 in the middle. Then, by opening the valve B, the pipe line 1 can communicate with the atmosphere. In addition, a soundproof net 9 is provided around the silencer 8 and has a configuration in consideration of noise to the surroundings.

Here, an example of the specifications of the entire system in this example is as follows. The diameter of the pipe line 1 is 600 A, the length is 2 km, the negative pressure of the vacuum pump 6 is 10 kPa (−1 kgf / cm ² ) at maximum, and the compressor 3 a The maximum pressure is 0.7 MPa.

  The cleaning method in the pipeline in the system configured as described above is basically the same as the method described with reference to FIG. 1. First, as a first step, the valves A1, A2 and B are closed and the valve C is closed. The vacuum pump 6 is driven in the open state, and the inside of the pipe line 1 is depressurized to a negative pressure. Then, after closing the valve C, the valve A2 is opened. As a result, the atmosphere is sucked into the pipe line 1 through the temporary pipe 4, and the dust attached to the inner surface of the pipe line 1 is brought closer to the downstream end side of the pipe line 1. Thereby, the upstream end side in the pipe line 1 can be mainly cleaned.

  Next, as a second step, the valves A2 and B are closed and the compressor unit 3 is driven in a state where the valve A1 is opened. Then, the valve B is opened. Thereby, the dust adhering to the inner surface of the pipe line 1 and the dust floating in the pipe line 1 pass through the temporary pipe 7 and the valve B together with the gas in the pipe line 1 and are diffused into the atmosphere via the silencer 8. The Thereby, the downstream end side in the pipe line 1 can be mainly cleaned. By repeatedly performing the first step and the second step as one cycle, the inside of the pipe line 1 can be cleaned more cleanly.

  As described above, according to the first embodiment, the vacuum pipe 6 and the compressor 3 are used to place the inside of the pipe line 1 in a reduced pressure state or a pressure accumulation state, and then in an open state, thereby generating an air flow in the pipe body. Since the pipe main body can be directly cleaned using the generated air flow, a tank that has been necessary in the past is unnecessary, and the equipment for cleaning can be greatly simplified. That is, in the case of the cleaning method using the tank, as described above, it is necessary to install a tank having a capacity equal to or larger than that of the pipe line 1, whereas in this example, the vacuum pump 6 and the compressor unit 3 are installed. Since only the connection is required, the facility can be simplified. Further, since the tank is not used, it is possible to eliminate the need for cleaning in the tank, which has been conventionally required, and the cleaning efficiency can be improved.

Embodiment 2. FIG.
In the second embodiment, the pipe line 1 cleaned by the cleaning method of the first embodiment is used as a flushing tank.

FIG. 3 is a diagram illustrating a construction example of a system to which the in-pipe cleaning method according to the second embodiment is applied. In FIG. 3, the same parts as those in FIG.
First, the upstream end of the pipeline 30 to be cleaned is connected to the downstream end of the cleaned pipeline 1 cleaned by the cleaning method of the first embodiment via the valve B1 that opens and closes the cleaned pipeline 1. To do. The temporary pipe 7 is connected to the downstream end of the cleaning target pipe line 30 and communicates with the atmosphere via the silencer 8.

  In the system configured as described above, when cleaning the pipe 30 to be cleaned, the compressor unit 3 is driven with the valves A2 and B1 closed and the valve A1 opened, following the second step of the first embodiment. Then, pressure is stored in the cleaned pipeline 1 by filling the pressure (third step). Then, the valve B1 is opened (fourth step). Thereby, the dust remaining in the cleaning target pipe line 30 and the dust floating in the cleaning target pipe line 30 pass through the temporary pipe 7 together with the gas filled in the pipe line 1 and pass through the silencer 8 in the atmosphere. Escaped to. Thereby, the inside of the cleaning target pipeline 30 can be cleaned. By repeatedly performing the third process and the fourth process as one cycle, the inside of the cleaning target pipe line 30 can be cleaned more cleanly.

  Here, the second embodiment is different from the first embodiment in that the pipe line 1 itself cleaned by the cleaning method of the first embodiment is used as a tank. When a tank is used for pipe cleaning, there is a problem that it is difficult to install a tank having a required capacity as described in the prior art. However, according to the second embodiment, the pipe 1 to be installed is originally used as a tank, so that there is no inconvenience that the installation is difficult unlike the case where the tank is newly installed for cleaning. . Moreover, using the pipe line 1 as a tank corresponds to the fact that flushing using a large-capacity tank is possible, so that cleaning can be performed effectively even with a small number of repetitions, and the cleaning efficiency is improved. Is possible.

It is principle explanatory drawing of the cleaning of the in-pipe cleaning method of Embodiment 1 of this invention. It is a figure which shows the construction example of the system to which the cleaning method in a pipe line of Embodiment 1 of this invention is applied. It is a figure which shows the construction example of the system to which the cleaning method in a pipe line of Embodiment 2 of this invention is applied.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Pipe line 1a Both-ends surface 2 Temporary piping 3 Compressor unit 3a Compressor 3b Dehumidifier 4 Temporary piping 5 Pull-out piping 6 Vacuum pump 7 Temporary piping 8 Silencer 9 Soundproof net 10 Dust 20 Excavation part 30 Pipe line to be cleaned

Claims (4)

A first step comprising: closing a valve disposed at each of an upstream end and a downstream end of the pipeline; depressurizing the inside of the pipeline with a vacuum pump; and opening a valve at the upstream end of the pipeline; ,
An in-pipe cleaning method comprising: a second step of accumulating pressure in the pipe line by a compressor after closing the upstream end valve and opening the downstream end valve.   The in-pipe cleaning method according to claim 1, wherein the first step and the second step are repeated as one cycle. The cleaning target pipe is connected to the downstream end of the cleaned pipe that has been subjected to the first step and the second step and cleaned, and the cleaned pipe is used as a flushing tank,
A third step comprising: closing both upstream and downstream valves of the cleaned line; and accumulating pressure in the cleaned line with the compressor;
The in-pipe cleaning method according to claim 1, further comprising a fourth step including a step of opening a valve at a downstream end of the cleaned pipe line. The in-pipe cleaning method according to claim 3, wherein the third step and the fourth step are repeated as one cycle.

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