The present invention relates to a method of cleaning the inside of a coil pipe(s) of a heat exchanger and, more specifically, to a method of cleaning the inside of the cooling coil pipe(s) or heating coil pipe(s) of the heat exchanger by forcing water and ice to flow in the coil pipe(s) for removing off dirt deposits such as slime, sludge and residue.
As well known, a heat exchanger transfers heat from a heat transfer medium (e.g., water or steam) passing through in a coil pipe(s) to other medium (e.g., air or water) flowing along the outside of the coil pipe(s) to cool or heat the latter. Dirt deposited in the coil pipe(s) results in a decrease in working efficiency of the heat exchanger. For example, the decreased cooling or heating ability of air conditioners is resulted in most cases from dirt deposits in the cooling or heating coil pipe(s). Namely, the dirt deposited in the coil pipe(s) may prevent the heat exchange between the heating or cooling medium flowing therein and the air flowing along the outside of the coil pipe(s). The buildup of slime, sludge and residue in the coil pipe(s) may also reduce the passage of heat transfer medium (cold or hot water in case of air conditioner) in the coil pipe(s), resulting in lowering the flow rate of the medium flowing therein than the nominal value necessary for achieving designed temperature difference between two fluids cannot be achieved.
For example, a cooling coil pipe(s) or heating coil pipe(s) of a heat exchanger (for chilled or hot water) of an air conditioner may be severely fouled in 10-15 years' use. This results in lowered cooling or heating capacity and shortening the service life of the device. To recover the capacity of the air conditioner, it is usually conducted to increase the airflow rate, wash the fin side (air side) of the heat exchanger coil pipe(s) with high-pressure water and, in rare cases, clean the inside of the heat exchanger coil pipe(s) (heat transfer side) with cleaning agent.
As described above, a heat exchanger coil pipe(s) is usually cleaned by washing its outside wall (air side) and, in rare cases, by flushing its inside wall (water side) with chemical solution. With regard to waste piping, the present applicant has proposed washing the inside of waste pipes with ice cubes in Japanese Patent Publication No. 1-28625.
However, the use of cleaning chemicals is accompanied by a risk of corroding the inside wall of the heat exchanger coil pipe(s) and polluting the environment with waste solution containing residue of chemicals. Therefore, there has been desired a method of cleaning the inside of heat exchanger coil pipe(s), which is friendly both to the heat exchanger coil pipe(s) and the ecological environment. The present invention is directed to a cleaning method that can satisfy the above-described requirements.
An object of the present invention is to provide a method of cleaning the inside of a heat exchanger coil pipe(s), which comprises a suction pump, a waste water collecting tank, a suction hose for connection between a heat transfer medium inlet or outlet of the heat exchanger coil pipe(s) and an inlet port of the waste water collecting tank and an ice supply hose provided at its one end with a hopper and connected at its other end to the outlet or inlet of the heat exchanger coil pipe(s), whereby the inside of the coil pipe(s) is cleaned with ice and water supplied thereto from the hopper through the ice supply hose, which by suction from the suction pump passes through the coil pipe(s) and enters into the waste water collecting tank.
Another object of the present invention is to provide a method of cleaning the inside of a heat exchanger coil pipe(s), whereby the cleaning is repeated in reverse direction by exchanging the connection of the inlet or outlet of the coil pipe(s) to the suction hose for the connection to the ice supply hose and by supplying ice and water into the coil pipe(s) and collecting the waste into the tank.
Another object of the present invention is to provide a method of cleaning the inside of a heat exchanger coil pipe(s), wherein the waste-and-wash water passing the heat exchanger coil pipe(s) is visually monitored in the transparent portion of the ice supply hose.
Another object of the present invention is to provide a method of cleaning the inside of a heat exchange coil pipe(s), whereby a mixture of ice and water, prepared in the ratio of 1 (ice) to 4˜6 (water), is supplied from the hopper into the coil pipe(s).
Another object of the present invention is to provide a method of cleaning the inside of a heat exchange coil pipe(s), whereby ice is prepared in form of cubes each having a side length corresponding to ⅓-⅔ of an inner diameter of the coil pipe(s) to be cleaned.
The present invention relates to a method of cleaning the inside of a heat exchanger coil pipe(s) as described above. In
On completion of the connections of the cleaning system as shown in
As described above, according to the present invention, the ice and water (ice only, water only or a mixture of ice and water may be used in practical cases) is forced by suction from the suction pump to flow through the heat exchanger coil pipe(s) in which rust, fur and slime deposited on the inner wall of the coil pipe(s) are removed off by the impact of collision of ice cubes therewith and washed out by water stream together with sludge (dust and sand), weld slugs and pipe-cut chips remaining in the coil pipe(s).
As described above, according to the present invention, it is possible to:
The cleaning method according to the present invention offers the following advantages:
The results of experiments indicate tat a mixture of ice and water, which was prepared in a ratio of 1 (ice): 5 (water), is suitable and the suitable size (one side length) of an ice cube corresponds to ⅓-⅔ of die inside diameter of a coil pipe(s) to be internally washed (for example, if the inside diameter of the coil pipe(s) is 15 mm, it is recommended to prepare ice cubes each having a side length of 5 to 10 mm)
The suction hose 13 having a transparent portion 13′ through which the dirty degree of waste-and-wash water can be visually observed to easily judge the result of cleaning.
After cleaning the inside of the coil pipe(s) in the condition shown in
While washing the inside of coil pipes 4, the inner wall of the coil pipes 4 cannot be damaged by ice cubes since ice is softer than the copper coil pipes 4 and water can serves as lubricant. High negative pressure (vacuum) is created in the inside of the coil pipes by suction from the suction pump to achieve effective flushing with ice and water, removing dirt deposits from the inside wall of the coil pipes 4. The sticky dirt deposits can be washed away by repeating several times flushing with ice and water alternating the flushing direction, i.e., from the top to the bottom of the coil pipe and from the bottom to the top thereof.
Number | Date | Country | Kind |
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2003-135595 | May 2003 | JP | national |
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Number | Date | Country | |
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20040226580 A1 | Nov 2004 | US |