Cleaning and liquid contact with solids – Processes – Using solid work treating agents
Reexamination Certificate
2002-12-10
2004-04-27
El Arini, Zeinab (Department: 1746)
Cleaning and liquid contact with solids
Processes
Using solid work treating agents
C134S006000, C134S007000, C134S16600C, C134S16900A
Reexamination Certificate
active
06726778
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a method for cleaning and renovating pipelines, in particular for cleaning and renovating pipelines which are difficult to access, such as pipelines buried underground, installed in walls, and the like
BACKGROUND OF THE INVENTION
As is well known, after pipelines have been in use for some time incrustation accumulates therein, which arises partly from salts in the fluids passing therethrough and partly from corrosion of the pipelines. The incrustation usually further includes thick and tough deposits of micro-organisms such as algae, bacteria, etc., which steadily increase over time. The pipelines can be cleaned by chemical cleaning, knocking and mechanical cleaning. These cleaning methods have their disadvantages and negative affects on the pipelines, or have limited applicabilities. A popularly used method is to clean the inner surface of the pipelines by supplying a fluid stream containing abrasive agents such as sand, through the pipelines so that the abrasive agents impinge upon the inner surfaces of the pipelines to remove the deposits thereon.
Examples of applying this method for pipeline cleaning are described in U.S. Pat. No. 1,890,164, entitled SAND BLASTING METHOD AND APPARATUS and issued to Rosenberger on Dec. 6, 1932, U.S. Pat. No. 2,087,694, entitled CLEANING PIPE and issued to Malmros on Jul. 20, 1937, U.S. Pat. No. 3,073,687, entitled METHOD FOR THE CLEANING OF PIPELINES and issued to McCune on Jan. 15, 1963 and U.S. Pat. No. 5,924,913, entitled PROCESS FOR RENOVATING PIPES and issued to Reimelt on Jul. 20, 1999.
More especially, in United Kingdom patent application 2,140,337, which is entitled CLEANING AND LINING A PIPE and published on Nov. 28, 1984, Shinno describes a method for renovating a pipe which comprises cleaning an internal surface of the pipe by supplying a fluid stream containing at least entrained abrasive agents and thereafter lining the pipe by introducing into the pipe a mixed stream of paint and air to deposit paint on the cleaned internal surface of the pipe. The mixture stream used in Shinno's cleaning and lining process is subjected to pulsations in a predetermined cycle and at a predetermined pulsation rate. Shinno states that in a conventional system, when a flow speed of the mixture stream reaches 30-100 m/sec, the air current is turbulent, and the flow speed near the inner surface of the pipe is slower than the flow speed at the center portion of the pipe. Shinno therefore suggests using a rotating vane as a pulsation-generating apparatus installed within the pipeline to be cleaned in order to reduce the fluid speed difference between the flow through the center of the pipe and the flow near the inner surface of the pipe. The suggested flow speed is 20-100 m/sec. Shinno's system is relatively complicated and it is not convenient to install the pulsation-generating apparatus in pipelines. The pulsation-generating apparatus installed in the pipelines can cause fluid flow resistance which is not desirable. The length of the pipelines which can be cleaned according to Shinno is about 30-100 meters, therefore more than 10 vertical holes would have to be dug in streets when, for example a one kilometer length of pipeline buried underground is to be cleaned. This is not satisfactory. Therefore a simple and efficient method for cleaning and renovating pipelines is desirable.
SUMMARY OF THE INVENTION
One object of the present invention is to provide a pipeline cleaning and renovating method in order to clean and renovate pipelines effectively.
In accordance with one aspect of the present invention, a method of cleaning a pipeline having open entry and exit ends, comprises steps of introducing a plurality of abrasive particulates into the pipeline from the entry end thereof by means of pressurized fluid; and controlling a flow of the pressurized fluid at the entry end of the pipeline to induce a substantially helical flow pattern along an inner surface of the pipeline, thereby causing a substantial amount of the abrasive particulates to move along the inner surface of the pipeline.
In accordance with another aspect of the present invention, a method of cleaning a pipeline having open entry and exit ends, comprises steps of introducing a plurality of abrasive particulates into the pipeline from the entry end thereof by means of pressurized air; introducing a liquid into the pipeline from the entry end thereof and thereby generating or increasing a moisture content of the liquid in a flow of the pressurized air; and controlling the flow of the pressurized air at the entry end of the pipeline to induce a substantially helical flow pattern along an inner surface of the pipeline, thereby causing a substantial amount of the abrasive particulates to move along the inner surface of the pipeline.
The method preferably comprises a further step after the pipeline is cleaned, of introducing a coating material into the pipeline by, for example an air flow in a substantially helical flow pattern along the inner surface of the pipeline, thereby moving a substantial amount of the coating material in the substantially helical flow pattern on and along the inner surface of the pipeline.
The substantially helical flow pattern is preferably obtained by controlling the speed of the air flow. In accordance with Applicant's test results, the flow speed through a pipeline reaches about 40 m/sec-100 m/sec the air flow is rotated to create a substantially helical flow pattern, although other flow patterns may jointly exist. The substantially helical flow pattern in the pipeline causes a substantial amount of the abrasive particulates or the coating material to move along the inner surface of the pipeline such that the inner surface of the pipeline is effectively cleaned or coated.
The pipeline cleaning and renovating method of the present invention advantageously provides very effective cleaning results for a relatively long length of pipelines at one time and uniform coating to the inner surface of the cleaned pipelines in order to protect the surface from incrustation for a relatively long period of time. The pipeline cleaning and renovating process is relatively easy to conduct which results in less labour and time consumption and thereby, lowers costs.
Other advantages and features of the present invention will be better understood with reference to the preferred embodiment of the present invention described hereinafter.
REFERENCES:
patent: 1890164 (1932-12-01), Rosengerger
patent: 2087694 (1937-07-01), Malmros
patent: 2089597 (1937-08-01), Carter
patent: 3073687 (1963-01-01), McCune
patent: 3082073 (1963-03-01), McAnneny
patent: 4583585 (1986-04-01), Estienne et al.
patent: 4684296 (1987-08-01), Horii et al.
patent: 4776794 (1988-10-01), Meller
patent: 4816296 (1989-03-01), Gibson
patent: 5007461 (1991-04-01), Naf
patent: 5013368 (1991-05-01), Maroy et al.
patent: 5045352 (1991-09-01), Mueller
patent: 5499659 (1996-03-01), Naf
patent: 5674323 (1997-10-01), Garcia
patent: 5783256 (1998-07-01), Matsuda et al.
patent: 5924913 (1999-07-01), Reimelt
patent: 6027572 (2000-02-01), Labib et al.
patent: 6155751 (2000-12-01), Lane et al.
patent: 2311049 (2001-10-01), None
patent: 000027980 (1981-05-01), None
patent: 2140337 (1984-11-01), None
patent: 449800 (1975-05-01), None
Wang Xiao Jun
Wang Xiao Ming
Bachman & LaPointe
El Arini Zeinab
JE Cleanpress Ltd. Co.
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