JPH0321720B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is applied to large-diameter pipes for gas, water, etc. that are buried underground, and when workers enter the pipes to work. Related to pipe air conditioners.

[Conventional technology]

When a worker enters a large-diameter underground pipeline as described above to repair the pipeline, forced replenishment of fresh air is essential to purify the air inside the pipe. For this reason, during the above-mentioned pipe work, a large blower was installed on the ground to blow a large amount of air into the pipe.

[Problem to be solved by the invention]

By the way, in underground pipes, the temperature of the inner wall surface of the pipe is relatively low, so in summer when there is a large temperature difference between underground and above ground, or during the rainy season when humidity is high, the moisture in the air introduced by the blower can be reduced. There was a problem in that the water adhered to the inner wall surface of the pipe, causing dew condensation, which hindered work inside the pipe.

As a countermeasure to this problem, it is possible to eliminate the above-mentioned dew condensation phenomenon by pre-cooling the introduced air using an air cooling device such as a cooler. Since a large-scale air cooling system is required to carry out this process, the equipment cost becomes extremely high and it is difficult to put it into practical use.

An object of the present invention is to provide an in-pipe air conditioner for a large-diameter pipe line that does not require a large-scale air cooling device and is economically free from condensation.

[Means to solve the problem]

In order to achieve this object, the present invention provides a large-diameter pipeline buried underground, with above-ground openings provided in required sections during pipe processing work, and a worker entering the pipeline through the opening. When working, an air conditioner with an air pre-cooling mechanism is installed on the ground near the opening, and the air conditioner has an outside air inlet on its intake side and a return air intake that takes in air from inside the pipe. It has an air suction port and a control valve that adjusts the ratio of air intake from both suction ports, and the recirculation air suction port is communicated with the inside of the pipe through a duct, and the cold air discharge port of the air conditioner is flexibly connected to this. The air blower duct is characterized in that the tip opening of the air blower duct is opened at a position close to a worker who is drawn into the pipe line from the above-ground opening and works inside the pipe.

[Effect]

In such a configuration, the cold air sent from the air conditioning equipment is directly supplied to the position near the worker working in the pipeline through the flexible ventilation duct, so the work can be done even with a small amount of outside air intake. Forced supply of fresh air to persons is fully achieved.

In addition, the relatively low-temperature, dehumidified air in the underground pipes is returned to the air conditioning equipment, reducing the burden of cooling and dehumidifying the intake air on the air conditioning equipment. Since the air is again blown into the working area of the pipe from the air conditioner, the temperature inside the pipe in the working area is balanced with the temperature of the inner wall of the pipe, and dew condensation does not occur on the inner wall of the pipe in the working area.

As a result, the amount of air supplied from the air conditioning equipment into the pipes is small enough to ensure air circulation within the pipes in the local area where the worker is located, but the amount of air supplied from the air conditioning equipment to the pipes is small enough to meet the intended purpose. Since the forced supply of fresh outside air and the prevention of dew condensation can be achieved at the same time, large-scale air conditioning equipment is no longer required, and the equipment costs for air conditioning can be reduced. become.

〔Example〕

Hereinafter, one embodiment of the present invention will be described based on the accompanying drawings. In FIG. 1, reference numeral 1 denotes a large-diameter underground pipe that is long underground and has a diameter that allows a person to enter the pipe and perform work. During pipe repair work, this large-diameter pipe 1 is divided into required lengths (usually 300 to 500 m) as a single repair unit, and the required width is cut out in a pit 2 that opens above the ground. There is an opening through which the person can enter and exit.

An air conditioner 4 equipped with an air precooling mechanism is installed on the ground near the opening of the pit 2. This air conditioner 4 is equipped with an outside air suction port 4b that takes in outside air from the atmosphere, and a recirculation air suction port 4c that takes in air from inside the pipe line 1, on its suction side. These outside air suction ports 4b and recirculation air suction ports 4c are connected to the air suction chamber 4 in the air conditioning equipment 4.
d, and there are both suction ports 4b,
A butterfly type control valve 5 is provided to adjust the ratio of the amount of air taken in from the suction chamber 4c to the suction chamber 4d. In addition, a heat exchanger 4e provided inside the air conditioner 4
is provided with a drain port 4f on its lower side through which water droplets condensed on the heat exchange fins due to cooling action can be discharged to the outside, and has a cold air discharge port 4a on its side,
A blower 7 is provided there.

A flexible bellows-shaped air duct 3 is connected to the air outlet of the blower 7 provided in the air conditioning equipment 4. It is pulled into the pipe line 1, and the open end of the tip is open to a position near the operator who enters the pipe and works. In addition, a return air duct 6 is separately connected to the return air suction port 4c provided in the air conditioner 4, and the other end of this duct 6 is also drawn into the pipe line 1 via the pit 2, and is opened at its tip end. The air in the pipe 1 is drawn in and returned to the air conditioner 4. The return duct 6 may be introduced into the pipe line 1 in parallel with the blower duct 3 as shown in FIG. or connect to the air duct 3 as shown in Figure 3.
It may be connected to the opening of the conduit 1 into which the pipe is drawn.

According to the embodiment configured in this way, the air conditioner 4 uses fresh outside air in the atmosphere taken in through the outside air suction port 4b, and pipe air inside the underground pipe 1 taken in through the recirculation air suction port 4c. is inhaled at a required flow rate by adjustment by the control valve 5. After this intake air is cooled in a heat exchanger 4e provided in the air conditioner 4, the cold air discharge port 4a is cooled.
The air is sent into the large-diameter pipe line 1 by the air blower 7 through the air duct 3, and is blown directly to the work area of the worker working inside the pipe.

When the air is blown directly to the worker's work area in this way, even a small amount of outside air intake is sufficient to forcibly supply fresh air to the worker inside the pipe.

In addition, the air conditioner 4 supplies air in the underground pipe 1, which is relatively low temperature and dehumidified and dry, to the duct 6.
This recirculation reduces the burden of cooling and dehumidifying the air conditioner 4, especially during the summer and rainy seasons, and at the same time, the air in the pipe 1 that is in such low temperature and dehumidified condition is recirculated from the air conditioner 4 into the pipe. By blowing air into the working area, the temperature inside the pipe in that working area is brought into equilibrium with the temperature on the inner wall of the pipe, and dew condensation does not occur on the inner wall of the pipe in the working area.

As a result, the amount of air supplied from the air conditioner 4 into the pipe line 1 is small enough to ensure air circulation within the pipe in the local area where the worker is located. Since the purpose of forcibly replenishing fresh outside air and preventing the occurrence of dew condensation on the inner wall of the pipe can be achieved at the same time, a large-scale air conditioner 4 is no longer necessary.

Note that if the outside air in the atmosphere is low humidity and low temperature, the control valve 5 is controlled to stop the recirculation of air from inside the pipe line 1, and only the outside air is taken in and sent into the pipe line 1 through the ventilation floor 7. Bye. At this time, the heat exchange action provided in the air conditioner 4 may be stopped.

〔Effect of the invention〕

As explained above, the present invention connects the return air suction port 4c of the air conditioner 4 installed above ground with the inside of the underground pipe 1 through the duct 6, and
The cold air outlet 4a is formed by drawing the tip opening of the blower duct 3 connected thereto into the conduit 1 from the ground opening and opening at a position near the worker.
The following effects can be obtained.

(1) First, the cold air sent from the air conditioner 4 is blown directly into the worker's work area inside the pipe, so even a small amount of outside air can be taken in.
Forced supply of fresh air to workers can be fully achieved.

(2) In addition, the relatively low temperature and dehumidified air in the underground pipe 1 is returned to the air conditioner 4 above ground, thereby cooling the intake air in the air conditioner 4.
At the same time, the burden of dehumidification is reduced, and since such recirculated air is again blown into the working area inside the pipe by the air conditioner 4, the temperature inside the pipe in the working area is brought into equilibrium with the temperature on the inside wall of the pipe. Condensation phenomenon no longer occurs on the inner wall of the pipe in the working area.

(3) As a result, the amount of air supplied from the air conditioner 4 into the pipe 1 is small enough to ensure air circulation within the pipe in the local area where the worker is located. As a result, the intended purpose of forcibly supplying fresh outside air and preventing dew condensation from occurring on the inner walls of the pipes can be achieved at the same time, making it unnecessary to use large-scale air conditioning equipment 4, making it more economical. The excellent effect of achieving air conditioning within a large-diameter pipe and greatly reducing equipment costs for air conditioning can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a schematic side view, partially in section, of an embodiment of the present invention, and FIGS. 2 and 3 are schematic side views showing other examples of arrangement of the return duct. 1...Large diameter pipe line, 2...Pit, 3...Blower duct, 4...Air conditioner, 4a...Cold air discharge port,
4b...Outside air suction port, 4c...Recirculation air suction port,
4d...Air suction chamber, 4e...Heat exchange chamber, 4f...
...Drain port, 5...Control valve, 6...Return duct, 7
...Air blower.

Claims (1)

[Scope of Claims] 1. In a large-diameter pipe buried underground, openings above the ground are provided in the required sections for processing work inside the pipe, and when a worker enters the pipe through the opening and works, An air conditioner with an air pre-cooling mechanism is installed on the ground near the opening, and the air conditioner has an outside air intake port and a recirculation air intake port that takes in air from inside the pipe on the intake side. , and a control valve that adjusts the air intake ratio from both suction ports, the recirculation air suction port is connected to the inside of the pipeline through a duct, and the cold air discharge port of the air conditioner is connected to a flexible air blower. The inside of a large-diameter pipe line, characterized in that a duct is connected to the air duct, and the tip opening of the air duct is opened at a position near a worker who is drawn into the pipe line from the above-ground opening and works inside the pipe. Air conditioner.