GB2123515A - Method and apparatus for preventing corrosion in a pipe interior surface - Google Patents
Method and apparatus for preventing corrosion in a pipe interior surface Download PDFInfo
- Publication number
- GB2123515A GB2123515A GB08237058A GB8237058A GB2123515A GB 2123515 A GB2123515 A GB 2123515A GB 08237058 A GB08237058 A GB 08237058A GB 8237058 A GB8237058 A GB 8237058A GB 2123515 A GB2123515 A GB 2123515A
- Authority
- GB
- United Kingdom
- Prior art keywords
- pig
- pipe
- film
- interior surface
- synthetic resin
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C63/00—Lining or sheathing, i.e. applying preformed layers or sheathings of plastics; Apparatus therefor
- B29C63/26—Lining or sheathing of internal surfaces
- B29C63/34—Lining or sheathing of internal surfaces using tubular layers or sheathings
- B29C63/341—Lining or sheathing of internal surfaces using tubular layers or sheathings pressed against the wall by mechanical means
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
- F16L58/00—Protection of pipes or pipe fittings against corrosion or incrustation
- F16L58/02—Protection of pipes or pipe fittings against corrosion or incrustation by means of internal or external coatings
- F16L58/04—Coatings characterised by the materials used
- F16L58/10—Coatings characterised by the materials used by rubber or plastics
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Protection Of Pipes Against Damage, Friction, And Corrosion (AREA)
- Cleaning In General (AREA)
Abstract
A method for preventing corrosion in a pipe interior surface utilizes a pig normally used for cleaning a pipe. A tubular synthetic resin film (6) is attached to a first pig (2) and is disposed in the pipe by running of the first pig through the pipe. The tubular film is then caused to adhere tightly to the pipe interior surface by running a second pig through the tubular film. An apparatus for carrying out this method comprises a pig launcher (3) and a drum unit (5) connected to the pig launcher and having a drum (5a) for winding the tubular synthetic resin film thereon. The method is simple and inexpensive and the protective film thus formed enjoys a long life for preventing corrosion in the pipe. <IMAGE>
Description
SPECIFICATION
Method and apparatus for preventing corrosion in a pipe interior surface
This invention relates to a method and apparatus for preventing occurrence of corrosion or scale in an interior surface of a metal pipe.
Corrosion and scale in a steel or other metal pipe pose serious problems to the industry.
Assuming, for instance, that the cost of electric power required for supplying water to a factory is about M200,000 per month (calculated on the basis of 16 yen per kilowatt), if scale is deposited on the interior surface of the pipe in the thickness of 20 mm, the cost of the electric power increases to about#1 ,200,000 per month, which is extremely uneconomical.
in chemical industries, metal pipes used for waste liquid disposal suffer from corrosion in their interior surface to such a degree that the whole pipe system must be changed once every two years.
A conventional method for preventing corrosion in the pipe interior surface is to apply coating over the pipe interior surface within a limited range of the pipe. According to this method, a coating carrier and a nozzle connected thereto are introduced into the pipe and conveyed in the pipe while the coating is sprayed over the interior surface of the pipe. In this conventional method, however, the length of the pipe which can be coated is not more than about 50 m. Besides, this method cannot be applied at all to a bent pipe.
Moreover, small holes are subsequently formed in the coating applied to the pipe interior surface due to evaporation of the solvent in the coating and water comes into contact with the metal surface of the pipe through these small holes in the coating resulting in corrosion of the metal surface.
The life of the pipe therefore is limited by this corrosion. Further, there is also limitation in uses of such coated pipes because they cannot be used for feeding of chemicals which will melt the coating applied to the interior surface of the pipes and because they are low in heat resistivity.
There are other anticorrosion methods including ones utilizing electrodes and applying linings of a synthetic rubber or plastic material.
These alternative methods are limited in their use because of difficulty and high cost in the application and difficulty in maintenance after the application.
It is, therefore, an object of the present invention to provide a method for preventing corrosion in a pipe interior surface eliminating the above described disadvantages of the conventional anticorrosion methods.
It is another object of the invention to provide an apparatus for carrying out the invention most effectively.
According to the invention, there is provided a method for preventing corrosion in a pipe interior surface comprising:
attaching an end portion of a tubular synthetic resin film to a first pig;
disposing the tubular synthetic resin film in the pipe by running the first pig through the pipe; and
running a second pig through inside of the tubular synthetic resin film disposed in the pipe to cause the film to adhere tightly to the pipe interior surface.
Further, according to the invention, there is provided an apparatus for preventing corrosion in a pipe interior surface comprising: a first pig to which an end portion of a tubular synthetic resin film can be attached; a second pig for pressing the tubular synthetic resin film to an interior surface of the pipe; a cylindrical pig launcher being capable of accommodating the pig and having an inlet for fluid for pushing the pig through the pipe; and a drum unit being connecfible to the rear end portion of the pig launcher and having a drum on which the tubular synthetic resin film can be wound.
The method according to the present invention is applicable to pipes of all purposes and all configurations including a long or bent pipe and a pipe with a step, is applicable in a very short period of time and at a remarkably low cost and the film thus formed is capable of enjoying a very long life. Since the deposition of the film is carried out by the running of the pig the speed of which is readily adjustable by adjusting the speed of the fluid under pressure, damage to the film or blocking of the film in the pipe due to an abrupt running of the film can be avoided by adjusting the speed of the fluid at an optimum valve. The protective film formed according to the method of the present invention is highly resistive to corrosion caused by chemicals.If the film made of fluorine-contained resin is used, the film can be used within the heat range of --2000CC-1 800 C.
In the accompanying drawings,
Fig. 1 is a sectional side elevation of an embodiment of the apparatus according to the invention;
Fig. 2 is a front view thereof;
Fig. 3 is a partly sectional view showing the process of causing the film to adhere to the pipe interior surface;
Fig. 4 is a sectional side elevation of another embodiment of the apparatus according to the invention;
Fig. 5 is a front view thereof;
Fig. 6(a) is a perspective view of the pig before attaching the film thereto; and
Fig. 6(b) is a side view of the pig after attaching the film thereto.
Referring first to Fig. 1, a steel pipe 1 in which a protective film is to be formed has a flange 1 a. A cylindrical pig launcher 3 is connected at its flange 3a to the flange 1 a of the pipe 1 by means of bolts 4. The pig launcher 3 is a device for launching a pig 2 which proceeds through the pipe for laying out a tubular synthetic resin film, as will be more fully described later. The launcher 3 has a water inlet 3b for supplying water under pressure for pushing the pig 2, a pressure gauge 3c and a pressure regulator valve 3d. The pig 2 loaded in the launcher 3 may be of any pig of known shape and material used for cleaning a pipe except that the pig 2 has a film fastening means 2a such as a wire rope for connecting the tubular synthetic resin film to the pig 2. This wire rope is buried in the pig 2 at one end thereof and is provided with a ring at the other end thereof.
A drum unit 5 to be connected to the pig launcher 3 comprises a housing 5c incorporating a drum 5b which is rotatably supported on a stationary shaft 5a through a roller bearing 5f and a cover 5d (Fig. 2). The housing 5c has a projecting portion 5e and the open end of the projection portion 5e has a flange Sg which can be connected to a flange 3e of the pig launcher 3 by means of bolts 7. The housing 5c has an air outlet valve 5b. Reference characters 12 and 13 designate packings.
A tubular synthetic resin film 6 for forming a pipe interior surface protective film is wound on the drum 5b in a flattened state. As the tubular synthetic resin film 6 to be used in the present invention, a tubular synthetic resin film having open ends, being slightly longer than the pipe in which the film is to be provided and having an outer diameter which is substantially equivalent to the inner diameter of the pipe is required. The tubular film may be made of a synthetic resin such, for example, as fluorine-contained resin, polyester resin, nylon and polyurethane resin. The thickness of the film may be chosen in a range between 0.1 mm and 10 mm depending upon the diameter of the pipe and the temperature of the fluid used in the pipe.
Forming of a protective film on the pipe interior surface is effected in the following manner:
The pig launcher 3 is fixed to the pipe 1. The pig 2 is loaded in the pig launcher 3. An end portion 6a of the tubular synthetic resin film 6 wound on the drum 5b of the drum unit 5 is fastened to the film fastening means 2a of the pig 2. The drum 5 is then connected to the pig launcher 3. The pig 2 is now ready for launching.
Water under pressure is supplied from the water inlet 3b of the launcher 3. As the water W (shown in a shaded portion in Fig. 1 ) fills up the pig launcher 3 and the housing 5c of the drum unit 5 communicating therewith, air in the housing 5c is driven out through the air outlet valve 5h. As the supplying of water is continued after the pig launcher 3 and the housing 5c are filled with water, the pig 2 is pushed by the water and runs through the pipe 1 in the direction of arrow A in
Fig. 1. As the pig 2 runs through the pipe 1, the tubular synthetic resin film 6 is fed from the drum 5b and reaches from one end of the pipe 1 to the other end thereof.Supplying of the water is now stopped. the film 6 is disconnected from the pig 2 and the pig launcher 3 and the drum unit 5 are disengaged from the pipe 1. Then the film 6 is cut to a required length (the film of a predetermined length may be previously wound on the drum).
After disposing the film 6 in the pipe 1 in the above described manner, the end portion of the film 6 nearer to the pig launcher 3 is spread in such a manner that the end portion of the film 6 covers the entire surface of the flange 1 a of the pipe 1. A short pipe 8 is then placed on the end portion of the film 6 and fastened to the flange 1 a by a suitable fastening device such as bolts.
Another pig launcher 3' which is closed at the rear end thereof is connected to the short pipe 8. A vacuum pump VP is connected to the flange 1 b through a short pipe 9. Reference character 11 denotes a pig stopper attached to the flange 1 b for stopping the running of the pig at the end portion of the pipe 1.
After completion of the above step, a second pig 2' is loaded in the pig launcher 3'. Any normally used type of pig may be used as the pig 2'. As water is supplied from a water inlet 3'b of the pig launcher 3', the pig 2' is pushed to run through the pipe 1 in such a manner that it goes through the tubular film 6 from its spread end portion. Simultaneously with the running of the pig 2', the vacuum pump VP is actuated to remove water and air remaining in the pipe 1.Since the pig 2' is made of an elastic material such as a foam urethane and has a diameter slightly larger than the inner diameter of the pipe 1, the running of the pig 2' through the tubular film 6 causes the film to be spread and pressed against the pipe interior surface so that the water and air between the outer surface of the film 6 and the pipe interior surface are completely removed and the film 6 is caused to tightly adhere to the pipe interior surface to form a protective film for the pipe interior surface. While the water and air between the film 6 and the pipe interior surface can be removed by the running of the pig 2' without the operation of the vacuum pump PV, the removal of the water and air can be ensured if the running of the pig 2' is effected simultaneously with the operation of the vacuum pump PV.After forming of the protective film on the pipe interior surface, the pig 2', vacuum pump VP, short pipe 9 and pig stopper 11 are dismounted from the pipe 1 and the end portion of the film 6 is secured to the flange 1 b by means of a suitable member such as a short pipe (not shown).
A A modified embodiment of the apparatus according to the invention is illustrated in Figs.
4-6. In this embodiment, the same reference characters as in the embodiment shown in Figs.
1-3 are used to designate the same component parts and detailed description thereof will be omitted.
The drum unit 5 shown in Fig. 4 is different from the drum unit 5 shown in Fig. 1 in that the former is of an integral cylindrical configuration without the cover 5d as in Fig. 1 and has a film roll inlet 5h at the opposite side of the projecting portion 5e and also has a pig inlet 5i in the upper portion of the projecting portion 5e. Reference characters 5j and 5k designate air outlet valves.
The positions of the film roll inlet 5h and the pig inlet 5i are of course not restricted to those shown in Fig. 4.
A pig 2 used in this embodiment has a reduced diameter portion 2a as shown in Figs. 6(a) and 6(b). For attaching the film 6 to the pig 2, the rear end portion 2b and the reduced diameter portion 2a of the pig 2 are covered by the spread end portion 6a of the film 6 as shown in Fig. 6(b). The film 6 is tied to the reduced diameter portion 2a by means of a wire rope 2c which in turn is covered by a plastic tape 2d. The tying means for tying the film 6 to the pig 2 is not limited to the wire rope 2c but other fastening device may be used. It should also be noted that the plastic tape 2d is not an essential component. The tying of the film 6 to the pig 2 is effected outside of the drum unit 5 by drawing the end portion of the film 6 out of the pig inlet 5i.The pig 2 to which the film 6 is attached is loaded into the pig launcher 3 through the pig inlet 5i and the drum unit 5.
The method according to the present invention can be carried out also by an apparatus which, instead of using the drum unit 5, uses a pig launcher 3 which has a closed rear end portion formed with a slit for inserting the tubular plastic film 6. In the above described embodiments, water under pressure is used to push the pigs 2 and 2' to run through the pipe 1. It is possible to use a compressed air, instead of water, to push the pigs 2 and 2'. In the case where the compressed air is used, however, a suitable lubricant needs to be applied on the pipe interior surface, for friction between the pipe interior surface and the film is much larger in the case where the compressed air is used than in the case where water is used. The advantage of using the water for pushing the pig is apparent, particularly in a bent pipe, for the water performs the function of the lubricant between the pipe interior surface and the film.
The above description has been made with respect to a case where a single layer of film is formed on the pipe interior surface. A multi-layer protective film may be formed by repeating the above described process for a desired number of times.
Claims (7)
1. A method for preventing corrosion or scale in a pipe interior surface comprising:
attaching an end portion of a tubular synthetic resin film to a first pig;
disposing the tubular synthetic resin film in the pipe by running the first pig through the pipe; and
running a second pig through inside of the tubular synthetic resin film disposed in the pipe to cause the film to adhere tightly to the pipe interior surface.
2. A method as defined in Claim 1 wherein the running of the first and second pigs is caused by water supplied under pressure from behind the pigs.
3. An apparatus for preventing corrosion in a pipe interior surface comprising:
a first pig to which an end portion of a tubular synthetic resin film can be attached;
a second pig for pressing the tubular synthetic resin film to an interior surface of the pipe;
a cylindrical pig launcher being capable of accommodating the pig and having an inlet for fluid for pushing the pig through the pipe; and
a drum unit being connectible to the rear end portion of the pig launcher and having a drum on which the tubular synthetic resin film can be wound.
4. An apparatus as defined in Claim 3 which further comprises means for attaching the tubular synthetic resin film to the first pig.
5. An apparatus as defined in Claim 3 wherein said first pig has a reduced diameter portion and a portion of the first pig is covered by the synthetic resin film and tied in the reduced diameter portion.
6. A method for preventing corrosion in a pipe interior surface substantially as hereinbefore described and exemplified.
7. An apparatus for preventing corrosion in a pipe interior surface substantially as hereinbefore described and exemplified.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP280282A JPS58121388A (en) | 1982-01-13 | 1982-01-13 | Method and apparatus for preventing corrosion of inner wall of pipe |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB2123515A true GB2123515A (en) | 1984-02-01 |
| GB2123515B GB2123515B (en) | 1985-09-11 |
Family
ID=11539503
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB08237058A Expired GB2123515B (en) | 1982-01-13 | 1982-12-31 | Method and apparatus for preventing corrosion in a pipe interior surface |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JPS58121388A (en) |
| GB (1) | GB2123515B (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2597782A1 (en) * | 1986-04-28 | 1987-10-30 | Sagawa Sizuo | Method for lining a pipe with a flexible cylindrical film |
| GB2193289B (en) * | 1986-02-20 | 1990-09-26 | Trest Juzhvodoprovod | Method of applying a protective coating to the inside surface of a pipeline wall and a device for carrying out the method |
| GB2238369A (en) * | 1988-01-19 | 1991-05-29 | Colin Brown | Encasing bundles of tubes in a sheath |
| US5412858A (en) * | 1988-01-19 | 1995-05-09 | Brown; Colin | Method of encasing bundles of tubes |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2017194078A (en) * | 2016-04-18 | 2017-10-26 | 株式会社ディスコ | Process of manufacture of double piping |
Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB714105A (en) * | 1951-08-18 | 1954-08-25 | Accumulatoren Fabrik Ag | Improvements in or relating to lined metal tubes |
| GB807413A (en) * | 1955-06-27 | 1959-01-14 | Tubovit Societa Per Azioni | Improved process for applying a thermoplastic inner lining to pipes made of non-thermoplastic material |
| GB1205170A (en) * | 1968-12-18 | 1970-09-16 | Ajinomoto Kk | Improvements in or relating to lining tubular members |
| GB1261952A (en) * | 1968-11-04 | 1972-02-02 | Raymond Muir Bremner | Pipe relining method |
| GB1266708A (en) * | 1968-11-04 | 1972-03-15 | ||
| GB1315468A (en) * | 1970-05-06 | 1973-05-02 | Northern Illinois Gas Co | Tools for app-ying internal pipe seals |
| GB1433932A (en) * | 1972-06-06 | 1976-04-28 | Du Pont | Method of lining a pipe structure and pulling head therefor |
| GB2018384A (en) * | 1978-04-05 | 1979-10-17 | Cahuzac D | Sheath for forming an internal lining for a conduit and a process for using the sheath |
| GB2065263A (en) * | 1979-11-22 | 1981-06-24 | Kankyo Kaihatsu Kk | Apparatus for reinforcing and repairing a pipe line |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5524324B2 (en) * | 1975-01-11 | 1980-06-28 | ||
| JPS5837891B2 (en) * | 1977-11-30 | 1983-08-19 | 大阪瓦斯株式会社 | Method for coating the inner surface of existing conduits |
| JPS5519574A (en) * | 1978-07-29 | 1980-02-12 | Osaka Gas Co Ltd | Internal lining of pipe |
-
1982
- 1982-01-13 JP JP280282A patent/JPS58121388A/en active Pending
- 1982-12-31 GB GB08237058A patent/GB2123515B/en not_active Expired
Patent Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB714105A (en) * | 1951-08-18 | 1954-08-25 | Accumulatoren Fabrik Ag | Improvements in or relating to lined metal tubes |
| GB807413A (en) * | 1955-06-27 | 1959-01-14 | Tubovit Societa Per Azioni | Improved process for applying a thermoplastic inner lining to pipes made of non-thermoplastic material |
| GB1261952A (en) * | 1968-11-04 | 1972-02-02 | Raymond Muir Bremner | Pipe relining method |
| GB1266708A (en) * | 1968-11-04 | 1972-03-15 | ||
| GB1205170A (en) * | 1968-12-18 | 1970-09-16 | Ajinomoto Kk | Improvements in or relating to lining tubular members |
| GB1315468A (en) * | 1970-05-06 | 1973-05-02 | Northern Illinois Gas Co | Tools for app-ying internal pipe seals |
| GB1433932A (en) * | 1972-06-06 | 1976-04-28 | Du Pont | Method of lining a pipe structure and pulling head therefor |
| GB2018384A (en) * | 1978-04-05 | 1979-10-17 | Cahuzac D | Sheath for forming an internal lining for a conduit and a process for using the sheath |
| GB2065263A (en) * | 1979-11-22 | 1981-06-24 | Kankyo Kaihatsu Kk | Apparatus for reinforcing and repairing a pipe line |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2193289B (en) * | 1986-02-20 | 1990-09-26 | Trest Juzhvodoprovod | Method of applying a protective coating to the inside surface of a pipeline wall and a device for carrying out the method |
| FR2597782A1 (en) * | 1986-04-28 | 1987-10-30 | Sagawa Sizuo | Method for lining a pipe with a flexible cylindrical film |
| GB2238369A (en) * | 1988-01-19 | 1991-05-29 | Colin Brown | Encasing bundles of tubes in a sheath |
| GB2238369B (en) * | 1988-01-19 | 1991-09-18 | Colin Brown | Method for encasing bundles of tubes |
| US5412858A (en) * | 1988-01-19 | 1995-05-09 | Brown; Colin | Method of encasing bundles of tubes |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS58121388A (en) | 1983-07-19 |
| GB2123515B (en) | 1985-09-11 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 19991231 |