CA2643695A1 - Method of resisting erosion in a pipe - Google Patents
Method of resisting erosion in a pipe Download PDFInfo
- Publication number
- CA2643695A1 CA2643695A1 CA 2643695 CA2643695A CA2643695A1 CA 2643695 A1 CA2643695 A1 CA 2643695A1 CA 2643695 CA2643695 CA 2643695 CA 2643695 A CA2643695 A CA 2643695A CA 2643695 A1 CA2643695 A1 CA 2643695A1
- Authority
- CA
- Canada
- Prior art keywords
- pipe
- iron
- powders
- aluminum oxide
- layer
- 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.)
- Abandoned
Links
- 238000000034 method Methods 0.000 title claims abstract description 33
- 230000003628 erosive effect Effects 0.000 title claims abstract description 18
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract description 103
- 239000000843 powder Substances 0.000 claims abstract description 55
- 229910052742 iron Inorganic materials 0.000 claims abstract description 51
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 claims abstract description 47
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 claims abstract description 41
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 claims abstract description 34
- 229910052721 tungsten Inorganic materials 0.000 claims abstract description 20
- 239000010937 tungsten Substances 0.000 claims abstract description 20
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims abstract description 17
- 229910052782 aluminium Inorganic materials 0.000 claims abstract description 16
- 238000001816 cooling Methods 0.000 claims abstract description 15
- 239000012809 cooling fluid Substances 0.000 claims abstract description 3
- 238000010438 heat treatment Methods 0.000 claims description 6
- 230000000977 initiatory effect Effects 0.000 claims description 4
- 238000000576 coating method Methods 0.000 abstract description 20
- 239000010410 layer Substances 0.000 description 28
- 239000011248 coating agent Substances 0.000 description 9
- 239000012530 fluid Substances 0.000 description 8
- 239000000463 material Substances 0.000 description 7
- 238000005299 abrasion Methods 0.000 description 4
- 230000015572 biosynthetic process Effects 0.000 description 4
- 239000011247 coating layer Substances 0.000 description 4
- 238000005260 corrosion Methods 0.000 description 4
- 230000007797 corrosion Effects 0.000 description 4
- 239000002826 coolant Substances 0.000 description 3
- 229910000831 Steel Inorganic materials 0.000 description 2
- 239000010959 steel Substances 0.000 description 2
- PNEYBMLMFCGWSK-UHFFFAOYSA-N Alumina Chemical group [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 239000000110 cooling liquid Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 238000010583 slow cooling Methods 0.000 description 1
- 238000007711 solidification Methods 0.000 description 1
- 230000008023 solidification Effects 0.000 description 1
- 238000009987 spinning Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- 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
- F16L58/08—Coatings characterised by the materials used by metal
-
- 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
- F16L9/00—Rigid pipes
- F16L9/14—Compound tubes, i.e. made of materials not wholly covered by any one of the preceding groups
Landscapes
- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Moulding By Coating Moulds (AREA)
Abstract
A method of resisting erosion in a pipe involves lining a pipe with aluminum and iron oxide powders which are ignited to subsequently form aluminum oxide and iron coatings on the inner surface of the pipe. Rotation of the pipe causes the heavier iron to be displaced radially outwardly relative to the aluminum oxide before the coatings cool and solidify. The quality of the coatings is improved by quickly cooling the pipe in a surrounding mold using a cooling fluid and subsequently releasing the mold in a radial direction of the pipe. The quality of the coatings is further improved by rotating the pipe until the powders are uniformly distributed prior to ignition of the powders. The quality of the coatings is yet further improved by igniting the powders with molten tungsten which ensures a fast and complete ignition of the powders.
Description
METHOD OF RESISTING EROSION IN A PIPE
FIELD OF THE INVENTION
The present invention relates to a method of resisting erosion in a pipe by lining a pipe to form an erosion resistant layer on an inner surface of the pipe.
BACKGROUND
In pipes for conveying fluid or materials therethrough and in containers for handling fluid or materials, the desirability of resisting erosion, abrasion and corrosion along an inner surface of the pipe or container is known for extending the life thereof. Conventional methods of lining pipes include spray-on coatings, however these tend to bond poorly and do not provide considerable resistance to erosion. Use of ceramic liners in pipes is also known, however this involves a complex process in which the liner is typically formed separately from the pipe and then later installed in the pipe in a time consuming and costly manner. In general, known erosion resistant coatings do not provide suitable resistance to erosion while being readily applied to pipes.
US Patent Application Publication No. 2003/0192613 by Zhen Wang discloses a Pipe and Method of Resisting Erosion, Abrasion and Corrosion in which a steel pipe is lined with iron and aluminum oxide by applying aluminum and iron oxide as powders and igniting the powders to form an exothermic and self-propagating reaction which fuses the resultant materials to the inner surface of the pipe.
When applying the pipe lining in the manner described in the prior publication, it is difficult to efficiently ignite the powders and distribute the materials evenly to obtain a uniform coating, resulting in a lower quality coating. Also, in order for the pipe to be released from the mold as described in the prior publication, the pipe and mold must be cooled slowly to prevent the pipe from being lodged in the mold, however the slow cooling can have a negative effect on lining quality.
SUMMARY OF THE INVENTION
According to one aspect of the invention there is provided a method of resisting erosion in a pipe comprising:
providing a pipe having a tubular body;
surrounding the pipe with a pipe mold;
applying aluminum as a powder and iron oxide as a powder to an inner surface of the tubular body;
initiating an exothermic reaction between the aluminum and the iron oxide to form aluminum oxide and iron;
rotating the pipe about a longitudinal axis of the pipe to separate the aluminum oxide and the iron into a layer of the iron and a layer of the aluminum oxide;
cooling the aluminum oxide and the iron by applying a cooling fluid to the pipe mold to solidify the layer of the iron directly adjacent the inner surface of the tubular body and to solidify the layer of aluminum oxide adjacent an inner surface of the layer of the iron; and releasing the pipe mold from the pipe in a generally radial direction relative to the pipe.
By providing a radially releasable mold, the mold can be tighten secured about the pipe during formation of the coating layers and subsequent cooling to prevent deformation of the pipe while remaining readily releasable even when subjected to a very rapid cooling, for example by a cooling liquid.
Accordingly, the advantages of better quality coating layers achieved by rapid cooling with fluids can be achieved.
According to a further aspect of the present invention there is provided a method of resisting erosion in a pipe comprising:
providing a pipe having a tubular body;
surrounding the pipe with a pipe mold;
applying aluminum as a powder and iron oxide as a powder to an inner surface of the tubular body;
rotating the pipe about a longitudinal axis of the pipe at a prescribed speed for a prescribed duration to distribute the powders about the inner surface of the tubular body;
initiating an exothermic reaction between the aluminum and the iron oxide to form aluminum oxide and iron;
rotating the pipe about a longitudinal axis of the pipe to separate the aluminum oxide and the iron into a layer of the iron and a layer of the aluminum oxide;
cooling the aluminum oxide and the iron to solidify the layer of the iron directly adjacent the inner surface of the tubular body and to solidify the layer of aluminum oxide adjacent an inner surface of the layer of the iron.
By rotating the pipe before ignition at a prescribed speed and a prescribed duration of rotation, a more even distribution of material can be achieved for forming more uniform and better quality resultant coating layers on the pipe as compared to prior art configurations.
According to a further aspect of the present invention there is provided a method of resisting erosion in a pipe comprising:
providing a pipe having a tubular body;
surrounding the pipe with a pipe mold;
applying aluminum as a powder and iron oxide as a powder to an inner surface of the tubular body;
FIELD OF THE INVENTION
The present invention relates to a method of resisting erosion in a pipe by lining a pipe to form an erosion resistant layer on an inner surface of the pipe.
BACKGROUND
In pipes for conveying fluid or materials therethrough and in containers for handling fluid or materials, the desirability of resisting erosion, abrasion and corrosion along an inner surface of the pipe or container is known for extending the life thereof. Conventional methods of lining pipes include spray-on coatings, however these tend to bond poorly and do not provide considerable resistance to erosion. Use of ceramic liners in pipes is also known, however this involves a complex process in which the liner is typically formed separately from the pipe and then later installed in the pipe in a time consuming and costly manner. In general, known erosion resistant coatings do not provide suitable resistance to erosion while being readily applied to pipes.
US Patent Application Publication No. 2003/0192613 by Zhen Wang discloses a Pipe and Method of Resisting Erosion, Abrasion and Corrosion in which a steel pipe is lined with iron and aluminum oxide by applying aluminum and iron oxide as powders and igniting the powders to form an exothermic and self-propagating reaction which fuses the resultant materials to the inner surface of the pipe.
When applying the pipe lining in the manner described in the prior publication, it is difficult to efficiently ignite the powders and distribute the materials evenly to obtain a uniform coating, resulting in a lower quality coating. Also, in order for the pipe to be released from the mold as described in the prior publication, the pipe and mold must be cooled slowly to prevent the pipe from being lodged in the mold, however the slow cooling can have a negative effect on lining quality.
SUMMARY OF THE INVENTION
According to one aspect of the invention there is provided a method of resisting erosion in a pipe comprising:
providing a pipe having a tubular body;
surrounding the pipe with a pipe mold;
applying aluminum as a powder and iron oxide as a powder to an inner surface of the tubular body;
initiating an exothermic reaction between the aluminum and the iron oxide to form aluminum oxide and iron;
rotating the pipe about a longitudinal axis of the pipe to separate the aluminum oxide and the iron into a layer of the iron and a layer of the aluminum oxide;
cooling the aluminum oxide and the iron by applying a cooling fluid to the pipe mold to solidify the layer of the iron directly adjacent the inner surface of the tubular body and to solidify the layer of aluminum oxide adjacent an inner surface of the layer of the iron; and releasing the pipe mold from the pipe in a generally radial direction relative to the pipe.
By providing a radially releasable mold, the mold can be tighten secured about the pipe during formation of the coating layers and subsequent cooling to prevent deformation of the pipe while remaining readily releasable even when subjected to a very rapid cooling, for example by a cooling liquid.
Accordingly, the advantages of better quality coating layers achieved by rapid cooling with fluids can be achieved.
According to a further aspect of the present invention there is provided a method of resisting erosion in a pipe comprising:
providing a pipe having a tubular body;
surrounding the pipe with a pipe mold;
applying aluminum as a powder and iron oxide as a powder to an inner surface of the tubular body;
rotating the pipe about a longitudinal axis of the pipe at a prescribed speed for a prescribed duration to distribute the powders about the inner surface of the tubular body;
initiating an exothermic reaction between the aluminum and the iron oxide to form aluminum oxide and iron;
rotating the pipe about a longitudinal axis of the pipe to separate the aluminum oxide and the iron into a layer of the iron and a layer of the aluminum oxide;
cooling the aluminum oxide and the iron to solidify the layer of the iron directly adjacent the inner surface of the tubular body and to solidify the layer of aluminum oxide adjacent an inner surface of the layer of the iron.
By rotating the pipe before ignition at a prescribed speed and a prescribed duration of rotation, a more even distribution of material can be achieved for forming more uniform and better quality resultant coating layers on the pipe as compared to prior art configurations.
According to a further aspect of the present invention there is provided a method of resisting erosion in a pipe comprising:
providing a pipe having a tubular body;
surrounding the pipe with a pipe mold;
applying aluminum as a powder and iron oxide as a powder to an inner surface of the tubular body;
applying molten tungsten to the powders so as to initiate an exothermic reaction between the aluminum and the iron oxide to form aluminum oxide and iron;
rotating the pipe about a longitudinal axis of the pipe to separate the aluminum oxide and the iron into a layer of the iron and a layer of the aluminum oxide;
and cooling the aluminum oxide and the iron to solidify the layer of the iron directly adjacent the inner surface of the tubular body and to solidify the layer of aluminum oxide adjacent an inner surface of the layer of the iron.
Use of molten tungsten provides an accurate control of the ignition of the powders and provides a sufficiently elevated ignition temperature that fast and complete ignition of the material results in a more uniform and thus an improved quality of coating layers as compared to the prior art.
In one embodiment, the mold comprises an outer frame surrounding the pipe, spaced radially outwardly from the pipe and a plurality of support members spanning radially inwardly to support pipe an inner ends centrally in the outer frame.
In this instance, the support members are preferably releasable in radial direction of pipe relative to outer frame and the pipe.
The support members may comprise screws for releasing the mold by rotating the screws.
The support members are preferably located at circumferentially spaced positions about the pipe and at axially spaced positions along the pipe.
According to an alternative embodiment, the mold comprises a plurality of sections each extending along a length of the pipe and extending only partway about a circumference of the pipe such that the plurality of sections together fully surround the pipe about the circumference thereof. The pipe is preferably released from the mold in this instance by releasing at least some of sections in the radial direction from the pipe.
The method may further include rotating the pipe about the longitudinal axis of the pipe until the powders are uniformly distributed about the pipe prior to 5 igniting the powders.
The molten tungsten may be applied to the powders by inserting a tungsten wire into pipe and heating the tungsten wire until molten tungsten forms by passing an electrical current through the tungsten wire.
There may be provided an elongate conductive member supporting the tungsten wire at a free end thereof. In this instance, the conductive member is preferably inserted into the pipe prior to passing an electrical current through elongate conductive member to heat the tungsten wire so that the molten tungsten is formed and applied to the powders at a location in the pipe spaced inwardly from one end of the pipe towards a central portion of the pipe.
Some embodiments of the invention will now be described in conjunction with the accompanying drawings in which:
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is an end view of a pipe which has been lined.
Figure 2 is an end view of the pipe shown supported in a mold for rotating the pipe.
Figure 3 is a side elevational view of the pipe shown supported in the mold.
Figure 4 is a flow chart illustrating the order of operations for lining the pipe.
Figure 5 is a sectional elevational view of an ignition system for igniting the powders in the pipe.
Figure 6 is an end view of further embodiment of the pipe mold supporting the pipe therein.
Figure 7 is an end view of another embodiment of the pipe mold supporting the pipe therein.
In the drawings like characters of reference indicate corresponding parts in the different figures.
DETAILED DESCRIPTION
Referring the accompanying drawings there is illustrated a pipe generally indicated by reference numeral 10. The pipe 10 includes a lining 12 coating an inner surface 14 thereof to prevent erosion of the inner surface while also providing a durable corrosion and abrasion resistant layer.
The pipe 10 includes a generally tubular body surrounding a longitudinal axis of the pipe. Respective ends 16 of the pipe are open for communication with adjacent sections of pipe when connected in a pipeline. The pipe is thus suitably arranged for conveying fluids and the like therethrough. The tubular body of the pipe has a steel composition.
The lining 12 of the inner surface 14 of the pipe includes a layer of iron 18 and a layer of aluminum oxide 20. The layers are fused onto the pipe such that the layer of iron 18 is located directly adjacent the inner surface 14 of the tubular body of the pipe while the aluminum oxide layer 20 is positioned radially inwardly in reEation to the iron layer adjacent an inner surface of the iron layer.
The lining is applied to the pipe by an apparatus 22 arranged for coating the inner surface of the pipe. The apparatus includes a mold 24 which is supported on a suitable rotating mechanism 26. The mold 24 is arranged to snuggly receive the pipe 10 to be coated therein. The rotating mechanism 26 includes a drive wheel 28 for engaging an outer surface of the mold to rotate the mold and an idler wheel 30 for supporting the mold 24 rotatably thereon.
The mold is sufficiently rigid to resist pipe deformation when the pipe is heated as the coating is being applied to the inner surface thereof. The mold includes a tubular portion 32 which snuggly receives the pipe 10 therein and a pair of end portions 34 capping respective ends of the tubular portion. Each end portion generally comprises an annular flange which spans radially inwardly from the ends of the tubular portion 32 about a full circumference of the tubular portion so as to abut respective ends of the pipe 10 when the pipe is received within the tubular portion 32 of the mold. The end portions are suitably arranged for containing a small amount of liquid adjacent an inner surface of the pipe 10. The mold includes a cooling mechanism for cooling the mold to resist deformation when the pipe is heated.
The method of operating the apparatus 22 for coating the inner surface 14 of the pipe 10 begins by first mixing aluminum powder and iron oxide powder in a ratio of 8 Al to 3 Fe304. The pipe is received within the mold 24 and capped by the end portions 34 thereof. The aluminum and iron oxide powders are distributed evenly about the inner surface 14 of the pipe within the mold which is rotated about the longitudinal axis of the tubular body of the pipe 10 prior to igniting the powders. The pipe is rotated at a prescribed speed arranged to distribute the powders and for a prescribed duration prior to igniting the powders corresponding to a duration required to evenly and uniformly distribute the powders about the circumference of the pipe.
Heating and igniting the powders within the pipe initiates a self-propagating exothermic reaction to produce aluminum oxide and iron in the ratio of 4 A1203 to 9 Fe. The self-propagating reaction generates sufficient heat to melt the products of the reaction so that the aluminum oxide and iron flow freely about the inner surface 14 of the pipe as a fluid. Despite the high temperatures, the rigid insulated mold resists deformation of the pipe.
Continued rotation of the mold about a longitudinal axis of the pipe and the mold causes the heavier iron particles to be displaced radially outwardly in relation to the aluminum oxide by the centrifugal spinning forces. The iron thus deposits itself in an iron layer directly adjacent the inner surface 14 of the pipe while the lighter aluminum oxide forms a harder layer adjacent an inner surface of the layer of iron.
Rotation of the mold continues until the iron and aluminum oxide layers have sufficiently cooled so as to mostly solidify. The pipe 10 may then be removed from the mold 24.
Turning now to Figure 5, an ignition system is disclosed for igniting the powder. The ignition system uses a tungsten wire 50 which is heated inside the pipe to form a molten tungsten which serves to ignite the powder when the molten tungsten comes into contact with the powder. The molten tungsten is applied to the powder at a location within the pipe spaced inwardly from one end of the pipe towards or near a centre of the pipe in the longitudinal direction thereof.
The ignition system comprises an elongate conductive member 52 which supports the tungsten wire 50 at a free end thereof. The tungsten wire is supported electrically in series with the conductive member so that passing an electrical current through the conductive member from a source 54 serves to sufficiently heat the wire that the tungsten becomes molten tungsten. The source 54 comprises a suitable portable source for providing an electrical current to the elongate conductive member. As illustrated, the source is supported on wheels for ease of portability.
rotating the pipe about a longitudinal axis of the pipe to separate the aluminum oxide and the iron into a layer of the iron and a layer of the aluminum oxide;
and cooling the aluminum oxide and the iron to solidify the layer of the iron directly adjacent the inner surface of the tubular body and to solidify the layer of aluminum oxide adjacent an inner surface of the layer of the iron.
Use of molten tungsten provides an accurate control of the ignition of the powders and provides a sufficiently elevated ignition temperature that fast and complete ignition of the material results in a more uniform and thus an improved quality of coating layers as compared to the prior art.
In one embodiment, the mold comprises an outer frame surrounding the pipe, spaced radially outwardly from the pipe and a plurality of support members spanning radially inwardly to support pipe an inner ends centrally in the outer frame.
In this instance, the support members are preferably releasable in radial direction of pipe relative to outer frame and the pipe.
The support members may comprise screws for releasing the mold by rotating the screws.
The support members are preferably located at circumferentially spaced positions about the pipe and at axially spaced positions along the pipe.
According to an alternative embodiment, the mold comprises a plurality of sections each extending along a length of the pipe and extending only partway about a circumference of the pipe such that the plurality of sections together fully surround the pipe about the circumference thereof. The pipe is preferably released from the mold in this instance by releasing at least some of sections in the radial direction from the pipe.
The method may further include rotating the pipe about the longitudinal axis of the pipe until the powders are uniformly distributed about the pipe prior to 5 igniting the powders.
The molten tungsten may be applied to the powders by inserting a tungsten wire into pipe and heating the tungsten wire until molten tungsten forms by passing an electrical current through the tungsten wire.
There may be provided an elongate conductive member supporting the tungsten wire at a free end thereof. In this instance, the conductive member is preferably inserted into the pipe prior to passing an electrical current through elongate conductive member to heat the tungsten wire so that the molten tungsten is formed and applied to the powders at a location in the pipe spaced inwardly from one end of the pipe towards a central portion of the pipe.
Some embodiments of the invention will now be described in conjunction with the accompanying drawings in which:
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is an end view of a pipe which has been lined.
Figure 2 is an end view of the pipe shown supported in a mold for rotating the pipe.
Figure 3 is a side elevational view of the pipe shown supported in the mold.
Figure 4 is a flow chart illustrating the order of operations for lining the pipe.
Figure 5 is a sectional elevational view of an ignition system for igniting the powders in the pipe.
Figure 6 is an end view of further embodiment of the pipe mold supporting the pipe therein.
Figure 7 is an end view of another embodiment of the pipe mold supporting the pipe therein.
In the drawings like characters of reference indicate corresponding parts in the different figures.
DETAILED DESCRIPTION
Referring the accompanying drawings there is illustrated a pipe generally indicated by reference numeral 10. The pipe 10 includes a lining 12 coating an inner surface 14 thereof to prevent erosion of the inner surface while also providing a durable corrosion and abrasion resistant layer.
The pipe 10 includes a generally tubular body surrounding a longitudinal axis of the pipe. Respective ends 16 of the pipe are open for communication with adjacent sections of pipe when connected in a pipeline. The pipe is thus suitably arranged for conveying fluids and the like therethrough. The tubular body of the pipe has a steel composition.
The lining 12 of the inner surface 14 of the pipe includes a layer of iron 18 and a layer of aluminum oxide 20. The layers are fused onto the pipe such that the layer of iron 18 is located directly adjacent the inner surface 14 of the tubular body of the pipe while the aluminum oxide layer 20 is positioned radially inwardly in reEation to the iron layer adjacent an inner surface of the iron layer.
The lining is applied to the pipe by an apparatus 22 arranged for coating the inner surface of the pipe. The apparatus includes a mold 24 which is supported on a suitable rotating mechanism 26. The mold 24 is arranged to snuggly receive the pipe 10 to be coated therein. The rotating mechanism 26 includes a drive wheel 28 for engaging an outer surface of the mold to rotate the mold and an idler wheel 30 for supporting the mold 24 rotatably thereon.
The mold is sufficiently rigid to resist pipe deformation when the pipe is heated as the coating is being applied to the inner surface thereof. The mold includes a tubular portion 32 which snuggly receives the pipe 10 therein and a pair of end portions 34 capping respective ends of the tubular portion. Each end portion generally comprises an annular flange which spans radially inwardly from the ends of the tubular portion 32 about a full circumference of the tubular portion so as to abut respective ends of the pipe 10 when the pipe is received within the tubular portion 32 of the mold. The end portions are suitably arranged for containing a small amount of liquid adjacent an inner surface of the pipe 10. The mold includes a cooling mechanism for cooling the mold to resist deformation when the pipe is heated.
The method of operating the apparatus 22 for coating the inner surface 14 of the pipe 10 begins by first mixing aluminum powder and iron oxide powder in a ratio of 8 Al to 3 Fe304. The pipe is received within the mold 24 and capped by the end portions 34 thereof. The aluminum and iron oxide powders are distributed evenly about the inner surface 14 of the pipe within the mold which is rotated about the longitudinal axis of the tubular body of the pipe 10 prior to igniting the powders. The pipe is rotated at a prescribed speed arranged to distribute the powders and for a prescribed duration prior to igniting the powders corresponding to a duration required to evenly and uniformly distribute the powders about the circumference of the pipe.
Heating and igniting the powders within the pipe initiates a self-propagating exothermic reaction to produce aluminum oxide and iron in the ratio of 4 A1203 to 9 Fe. The self-propagating reaction generates sufficient heat to melt the products of the reaction so that the aluminum oxide and iron flow freely about the inner surface 14 of the pipe as a fluid. Despite the high temperatures, the rigid insulated mold resists deformation of the pipe.
Continued rotation of the mold about a longitudinal axis of the pipe and the mold causes the heavier iron particles to be displaced radially outwardly in relation to the aluminum oxide by the centrifugal spinning forces. The iron thus deposits itself in an iron layer directly adjacent the inner surface 14 of the pipe while the lighter aluminum oxide forms a harder layer adjacent an inner surface of the layer of iron.
Rotation of the mold continues until the iron and aluminum oxide layers have sufficiently cooled so as to mostly solidify. The pipe 10 may then be removed from the mold 24.
Turning now to Figure 5, an ignition system is disclosed for igniting the powder. The ignition system uses a tungsten wire 50 which is heated inside the pipe to form a molten tungsten which serves to ignite the powder when the molten tungsten comes into contact with the powder. The molten tungsten is applied to the powder at a location within the pipe spaced inwardly from one end of the pipe towards or near a centre of the pipe in the longitudinal direction thereof.
The ignition system comprises an elongate conductive member 52 which supports the tungsten wire 50 at a free end thereof. The tungsten wire is supported electrically in series with the conductive member so that passing an electrical current through the conductive member from a source 54 serves to sufficiently heat the wire that the tungsten becomes molten tungsten. The source 54 comprises a suitable portable source for providing an electrical current to the elongate conductive member. As illustrated, the source is supported on wheels for ease of portability.
The conductive member 52 has a suitable cross sectional area and resistance so that the conductive member itself does not substantially overheat when passing electrical current therethrough to heat the tungsten wire at the free end of the conductive member. Ignition of the powder occurs by inserting the conductive member into the pipe from one end thereof so that the tungsten wire at the free end of the conductive member is located centrally within the pipe. When the electrical current is applied, and the wire forms molten tungsten, the molten tungsten will ignite the powder upon contact. When subsequently used, the tungsten wire is replaced with another tungsten wire for each ignition.
Turning now to Figures 6 and 7, further embodiments of the mold 24 are illustrated. In each instance the mold is arranged to be released in a radial direction relative to the pipe when removing the pipe from the mold, however the mold serves to tightly constrain the pipe in the radial direction about the full circumference thereof during the ignition of the powder and the subsequent cooling and solidification of the coatings on the inner surface of the pipe to prevent any deformation of the pipe. By permitting the mold to be released in a radial direction from the pipe, the material forming the coatings on the inner surface of the pipe can be cooled more quickly using a coolant fluid 56, for example water which is applied directly to the outside of the mold 24. Accordingly the mold and coatings cool much quicker than in prior art configurations to form a better quality lining without encountering subsequent problems of the deformation of the pipe and subsequent removal of the pipe from the mold as in prior art attempts.
Turning now more particularly to Figure 6, the mold in this instance comprises two separate mold portions 58 which are arranged to be readily releasable from one another. Each of the mold portions extends a full length of the pipe in the longitudinal direction while being arranged to extend only partway about a circumference of the pipe. The two mold portions are substantially equal in dimension in the circumferential direction so that each spans approximately half of the circumference of the overall circumference of the pipe. Opposing side edges of the 5 two mold portions are arranged to mate with one another in an interlocking and overlapping configuration in which one of the mold portions overlaps the other in a circumferential direction about the full length of the pipe to ensure that the mold can be constrained in a radial direction about the pipe during the formation of the coatings on the inner surface of the pipe. After cooling using a coolant fluid 56 as described 10 above, one or both of the mold portions is removed from the pipe in a radial direction of the pipe to permit the pipe to be released from the mold.
Turning now to figure 7, the mold 24 may alternatively comprise an external frame 60 which is generally tubular in shape and fully surrounds the pipe, but has an internal diameter which is greater than the external diameter of the pipe to define an annular gap therebetween with the external frame being spaced radially outward from the pipes.
A plurality of support members 62 are mounted on the external frame to span radially inward therefrom to a respective inner end 64 which engages the outer circumference of the pipe. The support members 62 are provided at a plurality of circumferentially and axially spaced positions relative to one another and relative to the pipe to fully surround and engage the pipe about the circumference thereof and along the length thereof for resisting deformation of the pipe during the formation of the coating on the inner surface thereof.
Each of the support members 62 is a threaded member or screw which is threadably received through a respective threaded bore in the external frame so that rotation of 'each support member 62 about its respective longitudinal axis causes the support member to be screwed inwardly and tightened in a radial direction inwardly towards the pipe when rotated in one direction while also being permitted to be screwed outwardly or loosened in a radially outward expanding direction relative to the pipe when rotated in the opposite direction.
Accordingly a pipe can be initially positioned within the external frame with the support members 62 being tightened about the pipe to constrain the pipe in the radial direction during formation of the coating thereon. After cooling of the external side of the mold using a coolant fluid 56 as noted above, the support members 62 can be turned to be released in a radially outward direction relative to the surrounding external frame which remains fixed and relative to the pipe so that the pipe can then be readily removed from the mold.
The method described herein may be adapted for various types of pipes or containers or other appliances for the similar purpose of resisting erosion by improving wear characteristics of the product being coated. Corrosion and abrasion resistant benefits of the aluminum oxide coating are also recognized.
Since various modifications can be made in my invention as herein above described, and many apparently widely different embodiments of same made within the spirit and scope of the claims without department from such spirit and scope, it is intended that all matter contained in the accompanying specification shall be interpreted as illustrative only and not in a limiting sense.
Turning now to Figures 6 and 7, further embodiments of the mold 24 are illustrated. In each instance the mold is arranged to be released in a radial direction relative to the pipe when removing the pipe from the mold, however the mold serves to tightly constrain the pipe in the radial direction about the full circumference thereof during the ignition of the powder and the subsequent cooling and solidification of the coatings on the inner surface of the pipe to prevent any deformation of the pipe. By permitting the mold to be released in a radial direction from the pipe, the material forming the coatings on the inner surface of the pipe can be cooled more quickly using a coolant fluid 56, for example water which is applied directly to the outside of the mold 24. Accordingly the mold and coatings cool much quicker than in prior art configurations to form a better quality lining without encountering subsequent problems of the deformation of the pipe and subsequent removal of the pipe from the mold as in prior art attempts.
Turning now more particularly to Figure 6, the mold in this instance comprises two separate mold portions 58 which are arranged to be readily releasable from one another. Each of the mold portions extends a full length of the pipe in the longitudinal direction while being arranged to extend only partway about a circumference of the pipe. The two mold portions are substantially equal in dimension in the circumferential direction so that each spans approximately half of the circumference of the overall circumference of the pipe. Opposing side edges of the 5 two mold portions are arranged to mate with one another in an interlocking and overlapping configuration in which one of the mold portions overlaps the other in a circumferential direction about the full length of the pipe to ensure that the mold can be constrained in a radial direction about the pipe during the formation of the coatings on the inner surface of the pipe. After cooling using a coolant fluid 56 as described 10 above, one or both of the mold portions is removed from the pipe in a radial direction of the pipe to permit the pipe to be released from the mold.
Turning now to figure 7, the mold 24 may alternatively comprise an external frame 60 which is generally tubular in shape and fully surrounds the pipe, but has an internal diameter which is greater than the external diameter of the pipe to define an annular gap therebetween with the external frame being spaced radially outward from the pipes.
A plurality of support members 62 are mounted on the external frame to span radially inward therefrom to a respective inner end 64 which engages the outer circumference of the pipe. The support members 62 are provided at a plurality of circumferentially and axially spaced positions relative to one another and relative to the pipe to fully surround and engage the pipe about the circumference thereof and along the length thereof for resisting deformation of the pipe during the formation of the coating on the inner surface thereof.
Each of the support members 62 is a threaded member or screw which is threadably received through a respective threaded bore in the external frame so that rotation of 'each support member 62 about its respective longitudinal axis causes the support member to be screwed inwardly and tightened in a radial direction inwardly towards the pipe when rotated in one direction while also being permitted to be screwed outwardly or loosened in a radially outward expanding direction relative to the pipe when rotated in the opposite direction.
Accordingly a pipe can be initially positioned within the external frame with the support members 62 being tightened about the pipe to constrain the pipe in the radial direction during formation of the coating thereon. After cooling of the external side of the mold using a coolant fluid 56 as noted above, the support members 62 can be turned to be released in a radially outward direction relative to the surrounding external frame which remains fixed and relative to the pipe so that the pipe can then be readily removed from the mold.
The method described herein may be adapted for various types of pipes or containers or other appliances for the similar purpose of resisting erosion by improving wear characteristics of the product being coated. Corrosion and abrasion resistant benefits of the aluminum oxide coating are also recognized.
Since various modifications can be made in my invention as herein above described, and many apparently widely different embodiments of same made within the spirit and scope of the claims without department from such spirit and scope, it is intended that all matter contained in the accompanying specification shall be interpreted as illustrative only and not in a limiting sense.
Claims (20)
1. A method of resisting erosion in a pipe comprising:
providing a pipe having a tubular body;
surrounding the pipe with a pipe mold;
applying aluminum as a powder and iron oxide as a powder to an inner surface of the tubular body;
initiating an exothermic reaction between the aluminum and the iron oxide to form aluminum oxide and iron;
rotating the pipe about a longitudinal axis of the pipe to separate the aluminum oxide and the iron into a layer of the iron and a layer of the aluminum oxide;
cooling the aluminum oxide and the iron by applying a cooling fluid to the pipe mold to solidify the layer of the iron directly adjacent the inner surface of the tubular body and to solidify the layer of aluminum oxide adjacent an inner surface of the layer of the iron; and releasing the pipe mold from the pipe in a generally radial direction relative to the pipe.
providing a pipe having a tubular body;
surrounding the pipe with a pipe mold;
applying aluminum as a powder and iron oxide as a powder to an inner surface of the tubular body;
initiating an exothermic reaction between the aluminum and the iron oxide to form aluminum oxide and iron;
rotating the pipe about a longitudinal axis of the pipe to separate the aluminum oxide and the iron into a layer of the iron and a layer of the aluminum oxide;
cooling the aluminum oxide and the iron by applying a cooling fluid to the pipe mold to solidify the layer of the iron directly adjacent the inner surface of the tubular body and to solidify the layer of aluminum oxide adjacent an inner surface of the layer of the iron; and releasing the pipe mold from the pipe in a generally radial direction relative to the pipe.
2. The method according to Claim 1 including forming the mold to comprise an outer frame surrounding the pipe, spaced radially outwardly from the pipe and a plurality of support members spanning radially inwardly to support pipe an inner ends centrally in the outer frame, the support members being releasable in radial direction of pipe relative to outer frame.
3. The method according to Claim 2 wherein the support members comprise screws and the method includes releasing the mold by rotating the screws.
4. The method according to any one of Claims 1 through 3 including locating the support members at circumferentially spaced positions about the pipe.
5. The method according to any one of Claims 1 through 4 including locating the support members at axially spaced positions along the pipe.
6. The method according to Claim 1 including forming the mold to comprise a plurality of sections each extending along a length of the pipe and extending only partway about a circumference of the pipe such that the plurality of sections together fully surround the pipe about the circumference thereof, and releasing at least some of sections in the radial direction from the pipe.
7. The method according to Claim 1 including rotating the pipe about the longitudinal axis of the pipe at a prescribed speed for a prescribed duration prior to igniting the powders to distribute the powders about the inner surface of the tubular body.
8. The method according to Claim 1 including rotating the pipe about the longitudinal axis of the pipe until the powders are uniformly distributed about the pipe prior to igniting the powders.
9. The method according to Claim 1 including applying molten tungsten to the powders to initiate the exothermic reaction between the aluminum and the iron oxide to form the aluminum oxide and the iron.
10. The method according to Claim 9 including applying the molten tungsten to the powders by inserting a tungsten wire into pipe and heating the tungsten wire until molten tungsten forms.
11. The method according to Claim 10 including heating the tungsten wire by passing an electrical current through the tungsten wire.
12. The method according to Claim 9 including applying the molten tungsten to the powders at a location in the pipe spaced inwardly from one end of the pipe towards a central portion of the pipe.
13. The method according to Claim 9 including providing an elongate conductive member, supporting a tungsten wire at a free end of the elongate conductive member, inserting the elongate conductive member into the pipe, and passing an electrical current through elongate conductive member to heat the tungsten wire and form the molten tungsten at a location in the pipe spaced inwardly from one end of the pipe.
14. A method of resisting erosion in a pipe comprising:
providing a pipe having a tubular body;
surrounding the pipe with a pipe mold;
applying aluminum as a powder and iron oxide as a powder to an inner surface of the tubular body;
rotating the pipe about a longitudinal axis of the pipe at a prescribed speed for a prescribed duration to distribute the powders about the inner surface of the tubular body;
initiating an exothermic reaction between the aluminum and the iron oxide to form aluminum oxide and iron;
rotating the pipe about a longitudinal axis of the pipe to separate the aluminum oxide and the iron into a layer of the iron and a layer of the aluminum oxide;
cooling the aluminum oxide and the iron to solidify the layer of the iron directly adjacent the inner surface of the tubular body and to solidify the layer of aluminum oxide adjacent an inner surface of the layer of the iron.
providing a pipe having a tubular body;
surrounding the pipe with a pipe mold;
applying aluminum as a powder and iron oxide as a powder to an inner surface of the tubular body;
rotating the pipe about a longitudinal axis of the pipe at a prescribed speed for a prescribed duration to distribute the powders about the inner surface of the tubular body;
initiating an exothermic reaction between the aluminum and the iron oxide to form aluminum oxide and iron;
rotating the pipe about a longitudinal axis of the pipe to separate the aluminum oxide and the iron into a layer of the iron and a layer of the aluminum oxide;
cooling the aluminum oxide and the iron to solidify the layer of the iron directly adjacent the inner surface of the tubular body and to solidify the layer of aluminum oxide adjacent an inner surface of the layer of the iron.
15. The method according to Claim 14 including rotating the pipe about the longitudinal axis of the pipe until the powders are uniformly distributed about the pipe prior to igniting the powders.
16. A method of resisting erosion in a pipe comprising:
providing a pipe having a tubular body;
surrounding the pipe with a pipe mold;
applying aluminum as a powder and iron oxide as a powder to an inner surface of the tubular body;
applying molten tungsten to the powders so as to initiate an exothermic reaction between the aluminum and the iron oxide to form aluminum oxide and iron;
rotating the pipe about a longitudinal axis of the pipe to separate the aluminum oxide and the iron into a layer of the iron and a layer of the aluminum oxide;
and cooling the aluminum oxide and the iron to solidify the layer of the iron directly adjacent the inner surface of the tubular body and to solidify the layer of aluminum oxide adjacent an inner surface of the layer of the iron.
providing a pipe having a tubular body;
surrounding the pipe with a pipe mold;
applying aluminum as a powder and iron oxide as a powder to an inner surface of the tubular body;
applying molten tungsten to the powders so as to initiate an exothermic reaction between the aluminum and the iron oxide to form aluminum oxide and iron;
rotating the pipe about a longitudinal axis of the pipe to separate the aluminum oxide and the iron into a layer of the iron and a layer of the aluminum oxide;
and cooling the aluminum oxide and the iron to solidify the layer of the iron directly adjacent the inner surface of the tubular body and to solidify the layer of aluminum oxide adjacent an inner surface of the layer of the iron.
17. The method according to Claim 16 including applying the molten tungsten to the powders by inserting a tungsten wire into pipe and heating the tungsten wire until molten tungsten forms.
18. The method according to Claim 17 including heating the tungsten wire by passing an electrical current through the tungsten wire.
19. The method according to Claim 16 including applying the molten tungsten to the powders at a location in the pipe spaced inwardly from one end of the pipe towards a central portion of the pipe.
20. The method according to Claim 16 including providing an elongate conductive member, supporting a tungsten wire at a free end of the elongate conductive member, inserting the elongate conductive member into the pipe, and passing an electrical current through elongate conductive member to heat the tungsten wire and form the molten tungsten at a location In the pipe spaced inwardly from one end of the pipe.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2643695 CA2643695A1 (en) | 2008-10-27 | 2008-10-27 | Method of resisting erosion in a pipe |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2643695 CA2643695A1 (en) | 2008-10-27 | 2008-10-27 | Method of resisting erosion in a pipe |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2643695A1 true CA2643695A1 (en) | 2010-04-27 |
Family
ID=42126249
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2643695 Abandoned CA2643695A1 (en) | 2008-10-27 | 2008-10-27 | Method of resisting erosion in a pipe |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2643695A1 (en) |
-
2008
- 2008-10-27 CA CA 2643695 patent/CA2643695A1/en not_active Abandoned
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| Date | Code | Title | Description |
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