CA2155036C - Pipeline pig and tooth therefor - Google Patents
Pipeline pig and tooth therefor Download PDFInfo
- Publication number
- CA2155036C CA2155036C CA002155036A CA2155036A CA2155036C CA 2155036 C CA2155036 C CA 2155036C CA 002155036 A CA002155036 A CA 002155036A CA 2155036 A CA2155036 A CA 2155036A CA 2155036 C CA2155036 C CA 2155036C
- Authority
- CA
- Canada
- Prior art keywords
- pig
- sleeve
- tooth
- shank
- pipeline
- 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.)
- Expired - Lifetime
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B08—CLEANING
- B08B—CLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL
- B08B9/00—Cleaning hollow articles by methods or apparatus specially adapted thereto
- B08B9/02—Cleaning pipes or tubes or systems of pipes or tubes
- B08B9/027—Cleaning the internal surfaces; Removal of blockages
- B08B9/04—Cleaning the internal surfaces; Removal of blockages using cleaning devices introduced into and moved along the pipes
- B08B9/053—Cleaning the internal surfaces; Removal of blockages using cleaning devices introduced into and moved along the pipes moved along the pipes by a fluid, e.g. by fluid pressure or by suction
- B08B9/055—Cleaning the internal surfaces; Removal of blockages using cleaning devices introduced into and moved along the pipes moved along the pipes by a fluid, e.g. by fluid pressure or by suction the cleaning devices conforming to, or being conformable to, substantially the same cross-section of the pipes, e.g. pigs or moles
- B08B9/0554—Diablo shaped pigs
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- Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Cleaning In General (AREA)
Abstract
Pipe cleaning pigs have a relatively short life expectancy and are ill adapted for cleaning any deposits harder than candle wax. A relatively simple solution to these problems involves a pipe cleaning pig including an elongated, one-piece, flexible, cylindrical body with hemispherical ends annular ribs integral with and extending outwardly from the body, longitudinal ribs extending between the annular ribs for strengthening the annular ribs and defining recesses with such annular ribs, and teeth in the recesses for engaging the interior of a pipe when the pig is moved through the pipe under fluid pressure.
Description
21~50~6 This is a divisional of Patent Application Serial No. 2,038,019, filed March 12, 1991.
This invention relates to a pig for cleaning a pipe or pipeline.
For the sake of simplicity, in the following, the term "pipeline" is used to describe a conventional pipeline or pipes used to convey fluids, e.g. in industrial heaters or cooling systems.
Pipelines are commonly used to transport, inter alia, a crude oil, gas, slurries or water. During use, the interior of a pipeline becomes coated which decreases flow through the pipeline. Typical coatings include paraffin, asphaltene, sediments, silica, coke, calcium or other salts and corrosion products which are often difficult or almost impossible to remove. The standard method of cleaning a pipeline is to drive a so-called pig through the pipeline using fluid pressure as the driving force. Pigs can also be used as dividers when transporting different materials through the pipeline, the pig simultaneously cleaning the interior of the pipeline.
Examples of pipeline cleaning pigs are described in United States Patents Nos. 2,447,966, issued to D.K. Stephens on August 24, 1948; 3,204,274, issued to M.M. Knapp on September 7, 1965; 3,277,508, issued to M.M. Knapp et al on October 1, 1968; 3,389,417, issued to M.M. Knapp et al on June 25, 1968; 3,538,531, issued to M.M. Knapp et al on November 10, 1970; 3,605,159, issued to H.J. Girard on September 20, 1971; 3,659,305, issued to M.D. Powers on May 2, 1972;
3,725,968, is6ued to M.M. Knapp et al on April 10, 1973;
3,863,287, issued to K.M. Knapp et al on February 4, 1975;
4,077,079, issued to M.M. Knapp on March 7, 1978; 4,244,073, issued to S. Sagawa on January 13, 1981; 4,509,222, issued to K.M. Knapp on April 9, 1985 and 4,603,449, issued to K.M.
Knapp on August 5, 1986.
In general, many existing pipeline pigs are incapable of cleaning deposits much harder than candle wax.
Those pigs which are adapted to clean hard deposits such as sediment and scale are not able to maintain a seal between separate products in a pipeline, and are prone to tearing on welds or other irregularities on the interior of the pipeline.
An object of the present invention is to solve the above problems by providing a relatively simple pipe or pipeline pig, which can remove hard deposits from the interior of a pipeline.
Another object of the invention is to provide a pipeline pig which can maintain a seal between different products in a pipeline, i.e. the pig can be used to clean only or to clean a pipeline and simultaneously separate products in the pipeline.
According to one aspect, the present invention relates to a pipeline pig comprising:
a body formed of elastic material;
a plurality of sleeves anchored in the body;
a plurality of teeth disposed about and extending radially outward from the sleeves;
- 21550:~6 the teeth and the sleeves each having radially accessible means cooperating with each other to detachably secure each detachable tooth within a corresponding sleeve.
According to another aspect, the invention relates to a detachable tooth for use in combination with a pipeline pig having a central portion, the detachable tooth being attachable to a sleeve radially disposed in the central portion of the pipeline pig, for use in scraping scale from the inside of pipes, the detachable tooth comprising:
a shank;
a head carried on the shank;
the head including a hexagonal base and a scraping portion remote from the shank; and means on the shank for cooperating with the sleeve to detachably secure the detachable tooth within the sleeve.
The invention will be described in greater detail with reference to the accompanying drawings, which illustrate a preferred embodiment of the invention, and wherein:
Figure 1 is a side elevational view of a pig in accordance with the present invention in a section of pipeline;
Figure 2 is a longitudinal sectional view of the pig taken generally along line II-II of Fig. 1;
Figure 3 is a cross section of the pig taken generally along line III-III of Fig. 1;
Figure 4 is an isometric view of a tooth used in the pig of Figs. 1 to 3;
- 21~036 ~igure 5 is an exploded, isometric view of the tooth of Fig. 4; and Figure 6 is a cross-sectional view of a portion of a mold used to produce the pig of Figs. 1 to 3.
Referring to Figs. 1 to 3, the pig of the present invention which is generally indicated at 1 is intended for use in a pipeline, a section 2 of which is shown in Fig. 1 for cleaning the interior 3 thereof. The pig 1 includes a one-piece elongated, flexible, cylindrical body 4 with hemispherical ends 5. The body is symmetrical, permitting travel in both directions which is important when using the pig in industrial heaters and similar pipelines. The body 4 is formed, e.g. of polyethylene, polypropylene, rubber or polyurethane. The flexibility and hardness of the body 4 are adapted to the intended use.
A wide annular rib 7 is provided at the center of the body 4, and two narrower annular ribs 8 are provided nearer to the ends 5 of the body. Thin, longitudinal ribs 10 extend between the ribs 7 and 8. The annular ribs 7 and 8, and the longitudinal ribs 10 define the sides and ends of square recesses 11, each of which contains a tooth 12.
Another circumferential row of recesses 13 is provided on each side of the central ribs 7 ~only one row shown). Each of the recesses 13 also contains a tooth 12. Additional ribs or fingers 14 extend outwardly from the outer side edge of each end rib 8. The fingers 14 are spaced equidistant apart around the periphery of the body 4, and taper outwardly from a wide inner end having the same thickness as the ribs 7 and 8 to a narrow outer end 16 (Fig. 1). The fingers 14 lend strength to the ribs 8 in the longitudinal direction. The dimensions and numbers of ribs 7, 8 and 10 and fingers 14 may vary depending upon the use of the pig, e.g. the seal required for pig travel through the pipeline. Moreover, the ribs and fingers can be formed of different material and have a different hardness from each other and from the remainder of the body 4. For example, the use of harder end ribs 8 may be required because of the fact that the end ribs define the leading ribs in the direction of pig travel, and thus are subjected to higher forces than the rib 7.
Each tooth 12 includes an internally threaded anchor or sleeve 17 for mounting in the body 4, and a separate threaded shank 18 (Fig. 5) carrying a head 19 for mounting in the sleeve 17. The plates 21 and 22 may also be circular.
Hexagonal flanges or plates 21 and 22 are provided on the bottom and top ends, respectively of the sleeve 17. The plate 21 anchors the sleeve 17 in the body 4, and the plate 22 limits movement of the sleeve into the body 4. The head 19 has a hexagonal base and a pyramidal pointed end 24. The sleeve 17, and the shank 18 and head 19 are formed of metal, but depending upon the intended use, can also be formed of plastic.
With reference to Fig. 6, the sleeves 17 are molded into the body using a mold (not shown), each half 25 of which contains threaded holes for receiving threaded sleeve holders 26. The sleeves 17 are mounted on the holders 26 in the mold cavity before the mold is closed. The mold is closed, and the body 4 is molded. The mold is opened, the holders 26 are removed and the body 4 is removed from the mold. The shanks 18 are threaded into the sleeves 17 to complete the pig.
In use, the pig is inserted into a pipe, and is S propelled therethrough by a fluid (gas or liquid) pressure gradient within the pipe. Pressure acting on one end of the pig body 4 causes expansion of the pig against the internal surface of the pipe, so that the teeth 12 are caused to scrape the interior surface of the pipe to dislodge material therefrom. Although it is not shown in Fig. 1, the outer diameter of the pig is normally equal to or slightly larger than the interior diameter of the pipe, so that the outer surface of the pig body 4 is forced against the internal surface of the pipe. As they become worn, the heads 19 of the teeth 12 can be moved outwardly by rotating the shank 18 in the sleeve 17, or removed and replaced. The plates 21 and 22 resist removal of the teeth 12 from the body 4, and prevent driving of the head 19 into the body 4.
Because the body 4 of the pig is symmetrical, the pig can be caused to reciprocate in a pipe for removing scale from an area with large accumulations. In cases where the pig is used to separate different materials in a pipeline, the teeth 12 can be omitted.
It will be appreciated that the recesses in the body of the pig can be circular rather than square or rectangular.
Moreover, the top plate on the tooth sleeve can be cup shaped or concavo/convex, so that it is recessed in the body for - 21a~036 certain uses-. The geometry of the head 19 of each tooth can also be different from that described above.
This invention relates to a pig for cleaning a pipe or pipeline.
For the sake of simplicity, in the following, the term "pipeline" is used to describe a conventional pipeline or pipes used to convey fluids, e.g. in industrial heaters or cooling systems.
Pipelines are commonly used to transport, inter alia, a crude oil, gas, slurries or water. During use, the interior of a pipeline becomes coated which decreases flow through the pipeline. Typical coatings include paraffin, asphaltene, sediments, silica, coke, calcium or other salts and corrosion products which are often difficult or almost impossible to remove. The standard method of cleaning a pipeline is to drive a so-called pig through the pipeline using fluid pressure as the driving force. Pigs can also be used as dividers when transporting different materials through the pipeline, the pig simultaneously cleaning the interior of the pipeline.
Examples of pipeline cleaning pigs are described in United States Patents Nos. 2,447,966, issued to D.K. Stephens on August 24, 1948; 3,204,274, issued to M.M. Knapp on September 7, 1965; 3,277,508, issued to M.M. Knapp et al on October 1, 1968; 3,389,417, issued to M.M. Knapp et al on June 25, 1968; 3,538,531, issued to M.M. Knapp et al on November 10, 1970; 3,605,159, issued to H.J. Girard on September 20, 1971; 3,659,305, issued to M.D. Powers on May 2, 1972;
3,725,968, is6ued to M.M. Knapp et al on April 10, 1973;
3,863,287, issued to K.M. Knapp et al on February 4, 1975;
4,077,079, issued to M.M. Knapp on March 7, 1978; 4,244,073, issued to S. Sagawa on January 13, 1981; 4,509,222, issued to K.M. Knapp on April 9, 1985 and 4,603,449, issued to K.M.
Knapp on August 5, 1986.
In general, many existing pipeline pigs are incapable of cleaning deposits much harder than candle wax.
Those pigs which are adapted to clean hard deposits such as sediment and scale are not able to maintain a seal between separate products in a pipeline, and are prone to tearing on welds or other irregularities on the interior of the pipeline.
An object of the present invention is to solve the above problems by providing a relatively simple pipe or pipeline pig, which can remove hard deposits from the interior of a pipeline.
Another object of the invention is to provide a pipeline pig which can maintain a seal between different products in a pipeline, i.e. the pig can be used to clean only or to clean a pipeline and simultaneously separate products in the pipeline.
According to one aspect, the present invention relates to a pipeline pig comprising:
a body formed of elastic material;
a plurality of sleeves anchored in the body;
a plurality of teeth disposed about and extending radially outward from the sleeves;
- 21550:~6 the teeth and the sleeves each having radially accessible means cooperating with each other to detachably secure each detachable tooth within a corresponding sleeve.
According to another aspect, the invention relates to a detachable tooth for use in combination with a pipeline pig having a central portion, the detachable tooth being attachable to a sleeve radially disposed in the central portion of the pipeline pig, for use in scraping scale from the inside of pipes, the detachable tooth comprising:
a shank;
a head carried on the shank;
the head including a hexagonal base and a scraping portion remote from the shank; and means on the shank for cooperating with the sleeve to detachably secure the detachable tooth within the sleeve.
The invention will be described in greater detail with reference to the accompanying drawings, which illustrate a preferred embodiment of the invention, and wherein:
Figure 1 is a side elevational view of a pig in accordance with the present invention in a section of pipeline;
Figure 2 is a longitudinal sectional view of the pig taken generally along line II-II of Fig. 1;
Figure 3 is a cross section of the pig taken generally along line III-III of Fig. 1;
Figure 4 is an isometric view of a tooth used in the pig of Figs. 1 to 3;
- 21~036 ~igure 5 is an exploded, isometric view of the tooth of Fig. 4; and Figure 6 is a cross-sectional view of a portion of a mold used to produce the pig of Figs. 1 to 3.
Referring to Figs. 1 to 3, the pig of the present invention which is generally indicated at 1 is intended for use in a pipeline, a section 2 of which is shown in Fig. 1 for cleaning the interior 3 thereof. The pig 1 includes a one-piece elongated, flexible, cylindrical body 4 with hemispherical ends 5. The body is symmetrical, permitting travel in both directions which is important when using the pig in industrial heaters and similar pipelines. The body 4 is formed, e.g. of polyethylene, polypropylene, rubber or polyurethane. The flexibility and hardness of the body 4 are adapted to the intended use.
A wide annular rib 7 is provided at the center of the body 4, and two narrower annular ribs 8 are provided nearer to the ends 5 of the body. Thin, longitudinal ribs 10 extend between the ribs 7 and 8. The annular ribs 7 and 8, and the longitudinal ribs 10 define the sides and ends of square recesses 11, each of which contains a tooth 12.
Another circumferential row of recesses 13 is provided on each side of the central ribs 7 ~only one row shown). Each of the recesses 13 also contains a tooth 12. Additional ribs or fingers 14 extend outwardly from the outer side edge of each end rib 8. The fingers 14 are spaced equidistant apart around the periphery of the body 4, and taper outwardly from a wide inner end having the same thickness as the ribs 7 and 8 to a narrow outer end 16 (Fig. 1). The fingers 14 lend strength to the ribs 8 in the longitudinal direction. The dimensions and numbers of ribs 7, 8 and 10 and fingers 14 may vary depending upon the use of the pig, e.g. the seal required for pig travel through the pipeline. Moreover, the ribs and fingers can be formed of different material and have a different hardness from each other and from the remainder of the body 4. For example, the use of harder end ribs 8 may be required because of the fact that the end ribs define the leading ribs in the direction of pig travel, and thus are subjected to higher forces than the rib 7.
Each tooth 12 includes an internally threaded anchor or sleeve 17 for mounting in the body 4, and a separate threaded shank 18 (Fig. 5) carrying a head 19 for mounting in the sleeve 17. The plates 21 and 22 may also be circular.
Hexagonal flanges or plates 21 and 22 are provided on the bottom and top ends, respectively of the sleeve 17. The plate 21 anchors the sleeve 17 in the body 4, and the plate 22 limits movement of the sleeve into the body 4. The head 19 has a hexagonal base and a pyramidal pointed end 24. The sleeve 17, and the shank 18 and head 19 are formed of metal, but depending upon the intended use, can also be formed of plastic.
With reference to Fig. 6, the sleeves 17 are molded into the body using a mold (not shown), each half 25 of which contains threaded holes for receiving threaded sleeve holders 26. The sleeves 17 are mounted on the holders 26 in the mold cavity before the mold is closed. The mold is closed, and the body 4 is molded. The mold is opened, the holders 26 are removed and the body 4 is removed from the mold. The shanks 18 are threaded into the sleeves 17 to complete the pig.
In use, the pig is inserted into a pipe, and is S propelled therethrough by a fluid (gas or liquid) pressure gradient within the pipe. Pressure acting on one end of the pig body 4 causes expansion of the pig against the internal surface of the pipe, so that the teeth 12 are caused to scrape the interior surface of the pipe to dislodge material therefrom. Although it is not shown in Fig. 1, the outer diameter of the pig is normally equal to or slightly larger than the interior diameter of the pipe, so that the outer surface of the pig body 4 is forced against the internal surface of the pipe. As they become worn, the heads 19 of the teeth 12 can be moved outwardly by rotating the shank 18 in the sleeve 17, or removed and replaced. The plates 21 and 22 resist removal of the teeth 12 from the body 4, and prevent driving of the head 19 into the body 4.
Because the body 4 of the pig is symmetrical, the pig can be caused to reciprocate in a pipe for removing scale from an area with large accumulations. In cases where the pig is used to separate different materials in a pipeline, the teeth 12 can be omitted.
It will be appreciated that the recesses in the body of the pig can be circular rather than square or rectangular.
Moreover, the top plate on the tooth sleeve can be cup shaped or concavo/convex, so that it is recessed in the body for - 21a~036 certain uses-. The geometry of the head 19 of each tooth can also be different from that described above.
Claims (5)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A pipeline pig comprising:
a body formed of elastic material;
a plurality of sleeves radially disposed about and anchored in the body;
a plurality of teeth disposed about the body and extending coaxially from the sleeves;
the teeth and the sleeves each having means cooperating with each other to detachably secure each detachable tooth within a corresponding sleeve.
a body formed of elastic material;
a plurality of sleeves radially disposed about and anchored in the body;
a plurality of teeth disposed about the body and extending coaxially from the sleeves;
the teeth and the sleeves each having means cooperating with each other to detachably secure each detachable tooth within a corresponding sleeve.
2. The pipeline pig of claim 1 in which the means includes the teeth having a threaded shank and the sleeves being threaded.
3. The pipeline pig of claim 1 in which the sleeves are secured in recesses in the body.
4. A detachable tooth for use in a pipeline pig having a central portion and a sleeve radially disposed in said central portion, the detachable tooth comprising:
a shank;
a head carried on the shank;
the head including a hexagonal base and a scraping portion remote from the shank; and means on the shank for cooperating with the sleeve to detachably secure the tooth within the sleeve.
a shank;
a head carried on the shank;
the head including a hexagonal base and a scraping portion remote from the shank; and means on the shank for cooperating with the sleeve to detachably secure the tooth within the sleeve.
5. The detachable tooth of claim 4 in which the sleeve has interior threads and the detachable tooth has exterior threads forming the means on the shank to detachably secure the tooth within the sleeve.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2038019 CA2038019C (en) | 1991-03-12 | 1991-03-12 | Pipeline pig and method of cleaning a pipe |
Related Parent Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2038019 Division CA2038019C (en) | 1991-03-12 | 1991-03-12 | Pipeline pig and method of cleaning a pipe |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2155036A1 CA2155036A1 (en) | 1992-09-13 |
| CA2155036C true CA2155036C (en) | 2000-10-31 |
Family
ID=4147167
Family Applications (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2038019 Expired - Lifetime CA2038019C (en) | 1991-03-12 | 1991-03-12 | Pipeline pig and method of cleaning a pipe |
| CA002155036A Expired - Lifetime CA2155036C (en) | 1991-03-12 | 1991-03-12 | Pipeline pig and tooth therefor |
Family Applications Before (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2038019 Expired - Lifetime CA2038019C (en) | 1991-03-12 | 1991-03-12 | Pipeline pig and method of cleaning a pipe |
Country Status (1)
| Country | Link |
|---|---|
| CA (2) | CA2038019C (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| PT975444E (en) | 1997-02-28 | 2005-03-31 | Watts Robert | INJECTOR SCRAPER WITH SOFT |
-
1991
- 1991-03-12 CA CA 2038019 patent/CA2038019C/en not_active Expired - Lifetime
- 1991-03-12 CA CA002155036A patent/CA2155036C/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| CA2038019C (en) | 1995-08-08 |
| CA2155036A1 (en) | 1992-09-13 |
| CA2038019A1 (en) | 1992-09-13 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKEX | Expiry |