CA2162622A1 - Skinned double wall pipe and apparatus for making same - Google Patents
Skinned double wall pipe and apparatus for making sameInfo
- Publication number
- CA2162622A1 CA2162622A1 CA002162622A CA2162622A CA2162622A1 CA 2162622 A1 CA2162622 A1 CA 2162622A1 CA 002162622 A CA002162622 A CA 002162622A CA 2162622 A CA2162622 A CA 2162622A CA 2162622 A1 CA2162622 A1 CA 2162622A1
- Authority
- CA
- Canada
- Prior art keywords
- plastic
- pipe
- die
- skin
- wall
- 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
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
- F16L11/00—Hoses, i.e. flexible pipes
- F16L11/14—Hoses, i.e. flexible pipes made of rigid material, e.g. metal or hard plastics
- F16L11/15—Hoses, i.e. flexible pipes made of rigid material, e.g. metal or hard plastics corrugated
-
- 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
- B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
- B29C48/001—Combinations of extrusion moulding with other shaping operations
- B29C48/0013—Extrusion moulding in several steps, i.e. components merging outside the die
- B29C48/0015—Extrusion moulding in several steps, i.e. components merging outside the die producing hollow articles having components brought in contact outside the extrusion die
-
- 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
- B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
- B29C48/03—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the shape of the extruded material at extrusion
- B29C48/13—Articles with a cross-section varying in the longitudinal direction, e.g. corrugated pipes
-
- 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
- B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
- B29C48/16—Articles comprising two or more components, e.g. co-extruded layers
- B29C48/18—Articles comprising two or more components, e.g. co-extruded layers the components being layers
- B29C48/21—Articles comprising two or more components, e.g. co-extruded layers the components being layers the layers being joined at their surfaces
-
- 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
- B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
- B29C48/25—Component parts, details or accessories; Auxiliary operations
- B29C48/30—Extrusion nozzles or dies
- B29C48/303—Extrusion nozzles or dies using dies or die parts movable in a closed circuit, e.g. mounted on movable endless support
-
- 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
- F16L9/18—Double-walled pipes; Multi-channel pipes or pipe assemblies
-
- 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
- B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
- B29C48/03—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the shape of the extruded material at extrusion
- B29C48/09—Articles with cross-sections having partially or fully enclosed cavities, e.g. pipes or channels
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
- B29L2016/00—Articles with corrugations or pleats
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
- B29L2023/00—Tubular articles
- B29L2023/18—Pleated or corrugated hoses
- B29L2023/186—Pleated or corrugated hoses having a smooth internal wall
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
- B29L2023/00—Tubular articles
- B29L2023/22—Tubes or pipes, i.e. rigid
Abstract
An extrusion die for making skinned double wall pipe has an elongated tubular body into which flowing plastic is injected. The tubular body has first and second plastic flow channels in which the first flow channel guides the flowing plastic to a first extrusion orifice in the die for making outer pipe wall and the second flow channel guides the flowing plastic to a second extrusion orifice in the die for making the inner pipe wall. The die also includes an injection opening to at least one of the plastic flow channels through which further plastic is injected to form the skin on the pipe.
Description
SJ-gllg-CA 2 1 62 62 2 TITLE: SKINNED DOUBLE WALL PIPE AND APPARATUS FOR MAKING
SAME
FIELD OF THE INVENTION
The present invention relates to a skinned double wall pipe and an extrusion die for simultaneously making and applying the skin to the pipe.
BACKGROUND OF THE INVENTION
The use of double wall pipe is becoming more and more popular and these pipes which can vary tremendously in size have many benefits over pipes having a single wall construction.
Extrusion dies for forming double wall pipes have been available on the market for some time now. Although the design of these dies may vary from one manufacturer to another, they all typically include an upstream injector which feeds plastic to parallel spaced apart plastic flow lines from which the plastic is extruded to form inner and outer pipe walls. These pipes may have smooth walls or they may have different configurations, such as a ribbed wall or the like.
In many applications, virgin material is required even though less expensive recycled material is available.
However, due to its inherent make-up, this recycled material will not provide certain requirements, such as chemical stability and smoothness in the pipe wall.
Furthermore, it is very difficult to introduce coloring to a conventionally formed double wall pipe. Wall coloring of the pipe can be very useful for things such as pipe identification purposes, and the like.
SUMMARY OF THE INVENT ION
The present invention provides a skinned double wall pipe and an apparatus for making skinned double wall pipe.
The provision of a skin on a double wall pipe provides numerous benefits which are not possible with conventionally unskinned double wall pipes. By way of example only, in cases where specific pipe properties are required for conveying material through the pipe, these properties can be provided by introducing a pipe skin formed from virgin material which will produce the required properties while the main walls of the pipe may be made from a much less expensive recycled material. As other examples, coloring agents, stabilizers, etc. can also be provided on the pipe through the use of the skin rather than being in the main body of the pipe.
The apparatus for forming double wall skinned pipe comprises an extrusion die having an elongated tubular body into which flowing plastic is injected. The tubular body is formed with first and second plastic flow channels. The first flow channel guides the flowing plastic to a first extrusion orifice in the die for making the outer pipe wall and the second flow channel guides the flowing plastic to a second extrusion orifice in the die for making the inner pipe wall. In addition, the die includes an injection opening to at least one of the plastic flow channels through which further plastic is injected to form the skin on the pipe. This injection opening can be provided to the first plastic flow channel for forming skin on the outer wall of the pipe or to the second plastic flow channel for forming a skin on the inner pipe wall or to both the first and the second plastic flow channels for forming a skin on both the outer and the inner pipe walls.
BRIEF DESCRIPTION OF THE DRAWINGS
The above as well as other advantages and features of the present invention will be described in greater detail according to the preferred embodiments of the present invention in which;
Figure 1 is a sectional view through the plastic flow region of an extruder die according to a preferred embodiment of the present invention;
Figure 2 is an enlargement of the skin injection region from the extruder die in Figure 1;
Figure 3 is a sectional view through one side of a double wall pipe made in accordance with a preferred embodiment of the present invention;
Figure 4 is a sectional view through the plastic flow region of an extruder die modified from that shown in Figure 1;
Figure 5 is a sectional view through one side of a double walled pipe made from the die of Figure 4;
Figure 6 is a sectional view through one side of a double wall pipe modified from that shown in Figure 5.
DETAILED DESCRIPTION ACCORDING TO THE PREFERRED
EMBODIMENTS OF THE PRESENT INVENTION
Figure 1 shows a section of an extruder die generally indicated at 1. This die has an upstream end 3 into which plastic material is fed by an injector in a flowing state. The die includes an elongated tubular region generally indicated at 5 downstream of the injection end. Tubular region 5 is formed by an outer tube wall 7, an inner tube wall 9 and a middle wall 11 between the two tube walls 7 and 9. The plastic as it flows down the extruder die, is divided into a first plastic flow channel 13 between walls 7 and 11 and into a second plastic flow channel 15 between walls 9 and 11. Channel 13 feeds to an extrusion orifice 17 while channel 15 feeds to an extrusion orifice 19.
The plastic flowing from the first extrusion orifice 17 will form the outer pipe wall while the plastic flowing from the second extrusion orifice 19 will form the inner pipe wall. The shape of the pipe will be determined by the shape of the mold surfaces (not shown) into which the plastic flows from the two extrusion orifices. By way of example only, figure 3 shows a double wall pipe generally indicated at 21 having a ribbed outer wall 23 and a flat inner wall 27. This is only one of many shapes that can be used when working with the extruder die of figure 1.
Returning to figure 1, an extrusion device generally indicated at 31 is in the form of a ring wrapping around the outer tube wall 7. Tube wall 7 is provided with an injection opening 33 into the flow channel 13. Injector 31 and the injection opening 33 are also well seen in figure 2 of the drawings. Here, it should be noted that injector 31 is located upstream of the first extrusion orifice 17 but downstream of the main injector end 3 of the die into which the plastic is injected for forming the pipe walls.
A second injection opening 39 is provided through the inner tube wall 9 to plastic flow channel 15.
A small channel 41 supplied plastic by an injection path through a spider interiorly of the tubular housing which feeds to an accumulator chamber 37 that, in turn feeds the injection opening 39.
Here, it should be noted that injection opening 39 is upstream of the second extrusion orifice 19.
The operation of the extruder die is as follows:
A parison of plastic material is injected into the die at the injection end 3. This plastic flows along the two flow channels 13 and 15. While the plastic is in a hot flowing state, skinning material is introduced to the channel 13 through the injection opening 33 which is fed by injection device 31. The material injected through injection opening 31 flows directly onto the exterior surface of the plastic material already flowing through channel 13. This ski nni ng material, because of its heated state, then bonds with the plastic material already in the channel which is also in the heated state to form a co-extrusion at the extrusion orifice 17. This co-extrusion comprises the outer pipe wall 23 and a skin 25 on the outer pipe wall as seen in figure 3 of the drawings. The skin 25 is formed from the material which is injected at injection opening 33.
In order to provide skin to the interior surface of the pipe, skinning material is introduced in a flowing state by an injection device which may be similar to device 31 along channel 41 to the accumulator chamber 37 which then feeds injection opening 39. This skinning material meets with the plastic already flowing in flow channel 15 and coats the interior of the plastic material. The two materials bind with one another to form a co-extrusion at the extrusion orifice 19. Figure 3 of the drawings shows the inner pipe wall 27 provided with an interior skin 29.
It is desirable to have the ability to vary the thickness of the skin on the pipe or to even eliminate the skin entirely. Figure 2 of the drawings shows the outer tube wall as including a tube wall section 35 having a threaded end 37 which engages with the threaded end 8 of the tube wall 7. This threaded connection of the tube wall section 35 allows it to be moved axially of the die to adjust the gap of injection opening 31 or, if desired, to SJ-gll9-CA 2 1 62622 completely close the injection opening. Similar or o~her adjustment systems can also be provided at the injection opening 39.
It should be noted that although the drawings show that the injection opening for the outer skin and the injection opening for the inner skin are at different locations along the length of the die, they can also be located at the same location within the die directly opposite one another.
It should also be appreciated that other adjustment systems can be used for adjusting or varying the gap in either of the injection openings.
The description above relates to the application of a skin to the outer surface of the outer pipe wall and the inner surface of the inner pipe wall. Figure 4 on the other hand shows a die 44 for the application of a skin between the two pipe walls and Figure 5 shows the actual pipe or tube formed using the device of Figure 4.
The basic construction of the die of Figure 4 is very similar to the die shown in Figure 2. It includes an outer die wall 47, a middle die wall 51 and an interior die wall 49 with plastic flow channels 53 and 55 being located between the various different die walls. However rather than including skin injection paths to the outer side of the outer plastic flow channel and to the inner side of the inner plastic flow channel, die 44 is provided with a spider 57 which carries a skin injection path 58 to an accumulator and injection opening 59. This injection opening injects to the inside of the outer plastic flow channel 53 to produce a double wall pipe 61 having an outer pipe wall 65, an inner pipe wall 63 and a skin 67 which acts as a bonding agent or adhesive to hold the two pipe walls together where they meet as shown in Figure 5.
Although Figure 4 shows the injection of the skin to the inner side of the outer plastic flow channel, the die can also easily be set up to inject the skin to the outer side of the inner flow channel to produce a pipe 71 as shown in Figure 6 having an inner pipe wall 73, an outer pipe wall 75 and a skin 77. This is achieved by relatively minor modifications to the spider 58 and by having the injection opening 59 open onto the inner rather than the outer plastic flow channel.
It will be clearly understood from the description above, that a double wall pipe made in accordance with the present invention can use recycled, less expensive plastic material in the formation of the main pipe walls while being coated with a skin made from virgin material and giving the pipe required properties for different applications. The skin, however, is much thinner than the main pipe walls and therefore substantially reduces the cost of the pipe in comparison to pipe made completely from virgin material. In addition, coloring agents, stabilizers, etc. can be added to the pipe through the use of the pipe skin.
Although various preferred embodiments of the present invention have been described herein in detail, it will be appreciated by those skilled in the art, that variations may be made thereto without departing from the spirit of the invention or the scope of the appended claims.
SAME
FIELD OF THE INVENTION
The present invention relates to a skinned double wall pipe and an extrusion die for simultaneously making and applying the skin to the pipe.
BACKGROUND OF THE INVENTION
The use of double wall pipe is becoming more and more popular and these pipes which can vary tremendously in size have many benefits over pipes having a single wall construction.
Extrusion dies for forming double wall pipes have been available on the market for some time now. Although the design of these dies may vary from one manufacturer to another, they all typically include an upstream injector which feeds plastic to parallel spaced apart plastic flow lines from which the plastic is extruded to form inner and outer pipe walls. These pipes may have smooth walls or they may have different configurations, such as a ribbed wall or the like.
In many applications, virgin material is required even though less expensive recycled material is available.
However, due to its inherent make-up, this recycled material will not provide certain requirements, such as chemical stability and smoothness in the pipe wall.
Furthermore, it is very difficult to introduce coloring to a conventionally formed double wall pipe. Wall coloring of the pipe can be very useful for things such as pipe identification purposes, and the like.
SUMMARY OF THE INVENT ION
The present invention provides a skinned double wall pipe and an apparatus for making skinned double wall pipe.
The provision of a skin on a double wall pipe provides numerous benefits which are not possible with conventionally unskinned double wall pipes. By way of example only, in cases where specific pipe properties are required for conveying material through the pipe, these properties can be provided by introducing a pipe skin formed from virgin material which will produce the required properties while the main walls of the pipe may be made from a much less expensive recycled material. As other examples, coloring agents, stabilizers, etc. can also be provided on the pipe through the use of the skin rather than being in the main body of the pipe.
The apparatus for forming double wall skinned pipe comprises an extrusion die having an elongated tubular body into which flowing plastic is injected. The tubular body is formed with first and second plastic flow channels. The first flow channel guides the flowing plastic to a first extrusion orifice in the die for making the outer pipe wall and the second flow channel guides the flowing plastic to a second extrusion orifice in the die for making the inner pipe wall. In addition, the die includes an injection opening to at least one of the plastic flow channels through which further plastic is injected to form the skin on the pipe. This injection opening can be provided to the first plastic flow channel for forming skin on the outer wall of the pipe or to the second plastic flow channel for forming a skin on the inner pipe wall or to both the first and the second plastic flow channels for forming a skin on both the outer and the inner pipe walls.
BRIEF DESCRIPTION OF THE DRAWINGS
The above as well as other advantages and features of the present invention will be described in greater detail according to the preferred embodiments of the present invention in which;
Figure 1 is a sectional view through the plastic flow region of an extruder die according to a preferred embodiment of the present invention;
Figure 2 is an enlargement of the skin injection region from the extruder die in Figure 1;
Figure 3 is a sectional view through one side of a double wall pipe made in accordance with a preferred embodiment of the present invention;
Figure 4 is a sectional view through the plastic flow region of an extruder die modified from that shown in Figure 1;
Figure 5 is a sectional view through one side of a double walled pipe made from the die of Figure 4;
Figure 6 is a sectional view through one side of a double wall pipe modified from that shown in Figure 5.
DETAILED DESCRIPTION ACCORDING TO THE PREFERRED
EMBODIMENTS OF THE PRESENT INVENTION
Figure 1 shows a section of an extruder die generally indicated at 1. This die has an upstream end 3 into which plastic material is fed by an injector in a flowing state. The die includes an elongated tubular region generally indicated at 5 downstream of the injection end. Tubular region 5 is formed by an outer tube wall 7, an inner tube wall 9 and a middle wall 11 between the two tube walls 7 and 9. The plastic as it flows down the extruder die, is divided into a first plastic flow channel 13 between walls 7 and 11 and into a second plastic flow channel 15 between walls 9 and 11. Channel 13 feeds to an extrusion orifice 17 while channel 15 feeds to an extrusion orifice 19.
The plastic flowing from the first extrusion orifice 17 will form the outer pipe wall while the plastic flowing from the second extrusion orifice 19 will form the inner pipe wall. The shape of the pipe will be determined by the shape of the mold surfaces (not shown) into which the plastic flows from the two extrusion orifices. By way of example only, figure 3 shows a double wall pipe generally indicated at 21 having a ribbed outer wall 23 and a flat inner wall 27. This is only one of many shapes that can be used when working with the extruder die of figure 1.
Returning to figure 1, an extrusion device generally indicated at 31 is in the form of a ring wrapping around the outer tube wall 7. Tube wall 7 is provided with an injection opening 33 into the flow channel 13. Injector 31 and the injection opening 33 are also well seen in figure 2 of the drawings. Here, it should be noted that injector 31 is located upstream of the first extrusion orifice 17 but downstream of the main injector end 3 of the die into which the plastic is injected for forming the pipe walls.
A second injection opening 39 is provided through the inner tube wall 9 to plastic flow channel 15.
A small channel 41 supplied plastic by an injection path through a spider interiorly of the tubular housing which feeds to an accumulator chamber 37 that, in turn feeds the injection opening 39.
Here, it should be noted that injection opening 39 is upstream of the second extrusion orifice 19.
The operation of the extruder die is as follows:
A parison of plastic material is injected into the die at the injection end 3. This plastic flows along the two flow channels 13 and 15. While the plastic is in a hot flowing state, skinning material is introduced to the channel 13 through the injection opening 33 which is fed by injection device 31. The material injected through injection opening 31 flows directly onto the exterior surface of the plastic material already flowing through channel 13. This ski nni ng material, because of its heated state, then bonds with the plastic material already in the channel which is also in the heated state to form a co-extrusion at the extrusion orifice 17. This co-extrusion comprises the outer pipe wall 23 and a skin 25 on the outer pipe wall as seen in figure 3 of the drawings. The skin 25 is formed from the material which is injected at injection opening 33.
In order to provide skin to the interior surface of the pipe, skinning material is introduced in a flowing state by an injection device which may be similar to device 31 along channel 41 to the accumulator chamber 37 which then feeds injection opening 39. This skinning material meets with the plastic already flowing in flow channel 15 and coats the interior of the plastic material. The two materials bind with one another to form a co-extrusion at the extrusion orifice 19. Figure 3 of the drawings shows the inner pipe wall 27 provided with an interior skin 29.
It is desirable to have the ability to vary the thickness of the skin on the pipe or to even eliminate the skin entirely. Figure 2 of the drawings shows the outer tube wall as including a tube wall section 35 having a threaded end 37 which engages with the threaded end 8 of the tube wall 7. This threaded connection of the tube wall section 35 allows it to be moved axially of the die to adjust the gap of injection opening 31 or, if desired, to SJ-gll9-CA 2 1 62622 completely close the injection opening. Similar or o~her adjustment systems can also be provided at the injection opening 39.
It should be noted that although the drawings show that the injection opening for the outer skin and the injection opening for the inner skin are at different locations along the length of the die, they can also be located at the same location within the die directly opposite one another.
It should also be appreciated that other adjustment systems can be used for adjusting or varying the gap in either of the injection openings.
The description above relates to the application of a skin to the outer surface of the outer pipe wall and the inner surface of the inner pipe wall. Figure 4 on the other hand shows a die 44 for the application of a skin between the two pipe walls and Figure 5 shows the actual pipe or tube formed using the device of Figure 4.
The basic construction of the die of Figure 4 is very similar to the die shown in Figure 2. It includes an outer die wall 47, a middle die wall 51 and an interior die wall 49 with plastic flow channels 53 and 55 being located between the various different die walls. However rather than including skin injection paths to the outer side of the outer plastic flow channel and to the inner side of the inner plastic flow channel, die 44 is provided with a spider 57 which carries a skin injection path 58 to an accumulator and injection opening 59. This injection opening injects to the inside of the outer plastic flow channel 53 to produce a double wall pipe 61 having an outer pipe wall 65, an inner pipe wall 63 and a skin 67 which acts as a bonding agent or adhesive to hold the two pipe walls together where they meet as shown in Figure 5.
Although Figure 4 shows the injection of the skin to the inner side of the outer plastic flow channel, the die can also easily be set up to inject the skin to the outer side of the inner flow channel to produce a pipe 71 as shown in Figure 6 having an inner pipe wall 73, an outer pipe wall 75 and a skin 77. This is achieved by relatively minor modifications to the spider 58 and by having the injection opening 59 open onto the inner rather than the outer plastic flow channel.
It will be clearly understood from the description above, that a double wall pipe made in accordance with the present invention can use recycled, less expensive plastic material in the formation of the main pipe walls while being coated with a skin made from virgin material and giving the pipe required properties for different applications. The skin, however, is much thinner than the main pipe walls and therefore substantially reduces the cost of the pipe in comparison to pipe made completely from virgin material. In addition, coloring agents, stabilizers, etc. can be added to the pipe through the use of the pipe skin.
Although various preferred embodiments of the present invention have been described herein in detail, it will be appreciated by those skilled in the art, that variations may be made thereto without departing from the spirit of the invention or the scope of the appended claims.
Claims (7)
1. An extrusion die for making skinned double wall pipe having an inner and an outer pipe wall, said die having an elongated tubular body into which flowing plastic is injected, said tubular body being formed with first and second plastic flow channels, the first flow channel guiding the flowing plastic to a first extrusion orifice in said die for making the outer pipe wall and the second flow channel guiding the flowing plastic to a second extrusion orifice for making the inner pipe wall, said die also including an injection opening into at least one of said plastic flow channels and through which further plastic is injected to form a skin on the pipe, said injection opening having an adjustable gap to vary thickness of the skin and said tubular body including a wall portion which is movable longitudinally of said tubular body to adjust said gap.
2. An extrusion die as claimed in claim 1 wherein said injection opening is provided in said first plastic flow channel upstream of said first extrusion orifice to form the skin on the outer pipe wall.
3. An extrusion die as claimed in claim 1 wherein said injection opening is provided in said second plastic flow channel upstream of said second extrusion orifice to form the skin on the inner pipe wall.
4. An extrusion die as claimed in claim 1 including injection openings in both of said plastic flow channels to form the skin on both the inner and the outer pipe walls.
5. An extrusion die for making skinned double wall pipe having an inner and an outer pipe wall, said die having an elongated tubular body into which flowing plastic is injected, said tubular body being formed by first and second plastic flow channels the first flow channel guiding the flowing plastic to a first extrusion orifice in said die for making the outer pipe wall and the second flow channel guiding the flowing plastic to a second extrusion orifice for making the inner pipe wall, said die also including an injection opening into one of said plastic flow channels and through which further plastic flows to form a skin which is thinner than and which is located between said inner and outer pipe walls and attached to at least one of said pipe walls.
6. A double wall thermoplastic pipe having an inner and outer pipe wall with a skin which is reduced in thickness relative to said pipe walls, said skin being located between and adhering said inner and outer pipe walls to one another.
7. A double wall pipe as claimed in Claim 6, wherein said skin is made from a different material from said pipe walls.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US08/337,031 US5542834A (en) | 1994-11-10 | 1994-11-10 | Skinned double wall pipe and apparatus for making same |
| US08/337,031 | 1994-11-10 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2162622A1 true CA2162622A1 (en) | 1996-05-11 |
Family
ID=23318803
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002162622A Abandoned CA2162622A1 (en) | 1994-11-10 | 1995-11-10 | Skinned double wall pipe and apparatus for making same |
Country Status (2)
| Country | Link |
|---|---|
| US (2) | US5542834A (en) |
| CA (1) | CA2162622A1 (en) |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| RU2142092C1 (en) * | 1995-04-03 | 1999-11-27 | Упонор Б.В. | Riffled tube manufacturing method and riffled tubes manufactured by means of this method |
| US5773035A (en) * | 1996-07-01 | 1998-06-30 | Alfacel S.A. | Tubular cellulosic casing die |
| US5846575A (en) * | 1997-03-17 | 1998-12-08 | Lupke; Manfred A. A. | Pipe forming mandrel with multiple sleeve inner tube |
| DE19724113A1 (en) * | 1997-06-09 | 1998-12-10 | Ralph Peter Dr Hegler | Composite pipe with molded pipe sleeve and method for its production |
| US6174478B1 (en) | 1998-09-25 | 2001-01-16 | Silver-Line Plastics Corporation | Method and apparatus for simultaneous extrusion of two triple-wall pipes |
| US6533564B1 (en) * | 1999-02-10 | 2003-03-18 | Jowat Corporation | Apparatus for forming adhesive cartridges |
| US7074027B2 (en) * | 2001-02-19 | 2006-07-11 | Starita Joseph M | Extrusion die and method for forming dual wall corrugated plastic pipe and dual wall plastic pipe having a foam annular core |
| WO2002081957A1 (en) * | 2001-04-04 | 2002-10-17 | Hancor, Inc. | Corrugation structure for pipe |
| NO20025536D0 (en) * | 2002-11-18 | 2002-11-18 | Norsk Hydro As | Flexible tubing, e.g. a tube bellows |
| DE102004037088B3 (en) * | 2004-07-30 | 2006-04-13 | Veritas Ag | Flexible hose, preferably charge air hose for motor vehicles |
| DE102006018374A1 (en) * | 2006-04-20 | 2007-10-25 | Drossbach Gmbh & Co Kg | Corrugated pipe made of thermoplastic material |
| CN102245954B (en) * | 2008-10-10 | 2014-01-15 | 迪亚能源股份有限公司 | Flexible multi-walled tubing assembly |
| US9662826B2 (en) * | 2013-08-12 | 2017-05-30 | Prinsco, Inc. | Coilable dual wall corrugated pipe and related method |
| JP6529584B2 (en) * | 2015-05-28 | 2019-06-12 | 三菱電機株式会社 | Flexible Tube |
| DE102016119332B4 (en) * | 2016-10-11 | 2021-06-24 | DROSSBACH Maschinenbau GmbH | Multi-layer corrugated plastic pipe |
| CN108799645A (en) * | 2018-09-01 | 2018-11-13 | 湛江市霞山信佳橡塑制品有限公司 | A kind of water-flowing device of four-layer structure |
| US11701035B2 (en) | 2019-10-28 | 2023-07-18 | Bruce M. Landy | Noninvasive blood glucose detector and method using IR |
| CN112361093B (en) * | 2020-11-17 | 2022-09-13 | 重庆四通八达管业有限公司 | Implanted early-warning reinforced basalt fiber composite pipeline and preparation process |
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|---|---|---|---|---|
| US2957201A (en) * | 1957-07-12 | 1960-10-25 | Continental Can Co | Extrusion die for two-ply seamless plastic tubing |
| US4342612A (en) * | 1978-03-10 | 1982-08-03 | Titeflex Corporation | Method of making a preformed semirigid plastic hose wrapped with a wire spiral |
| US4249875A (en) * | 1978-09-15 | 1981-02-10 | Cosden Technology, Inc. | Co-extrusion apparatus and method for producing multiple-layered thermoplastic pipe |
| US4269234A (en) * | 1979-05-18 | 1981-05-26 | Tri State Culvert Corporation | High strength pipe |
| DE3164861D1 (en) * | 1980-05-06 | 1984-08-23 | Grohe Kg Hans | Flexible reinforced plastic hose, in particular shower hose, and its method of manufacture |
| US4629650A (en) * | 1982-12-30 | 1986-12-16 | Asahi Kasei Kogyo Kabushiki Kaisha | Process for producing molded thermoplastic resin |
| US4627844A (en) * | 1985-10-30 | 1986-12-09 | High Voltage Engineering Corporation | Tri-layer tubing |
| US4812348A (en) * | 1986-06-11 | 1989-03-14 | Volkswagen Ag | Torsion-stressed component part of superposed fiber layers |
| SU1585613A1 (en) * | 1987-03-31 | 1990-08-15 | Предприятие П/Я Ю-9034 | High-pressure metal hose |
| US4789327B1 (en) * | 1988-02-25 | 2000-07-18 | Corma Inc | Adjustable pipe extrusion die with internal cooling |
| US5148837A (en) * | 1988-05-30 | 1992-09-22 | Uponor N.V. | Pipe for relining underground pipelines |
| US5108682A (en) * | 1990-07-24 | 1992-04-28 | Bridgestone/Firestone, Inc. | Coextrusion apparatus and method using an elastic die for varying the outer profile of a tubular extrudate |
| DE4210482A1 (en) * | 1992-03-31 | 1993-10-07 | Wilhelm Hegler | Method and device for the continuous production of a composite pipe with a pipe socket |
| US5284184A (en) * | 1992-04-14 | 1994-02-08 | Itt Corporation | Corrugated multi-layer tubing having at least one fluoroplastic layer |
| US5469892A (en) * | 1992-04-14 | 1995-11-28 | Itt Automotive, Inc. | Corrugated polymeric tubing having at least three layers with at least two respective layers composed of polymeric materials dissimilar to one another |
| US5439454A (en) * | 1992-05-14 | 1995-08-08 | Baxter International Inc. | Coextruded medical grade port tubing |
| DE9319879U1 (en) * | 1993-12-23 | 1994-03-17 | Inventa Ag | Sequentially co-extruded coolant line |
| DE9319880U1 (en) * | 1993-12-23 | 1994-03-17 | Inventa Ag | Blow molded coolant line |
| US5611373A (en) * | 1995-04-27 | 1997-03-18 | Handy & Harman Automotive Group, Inc. | Laminated fuel line and connector |
-
1994
- 1994-11-10 US US08/337,031 patent/US5542834A/en not_active Expired - Lifetime
-
1995
- 1995-11-10 CA CA002162622A patent/CA2162622A1/en not_active Abandoned
-
1996
- 1996-07-25 US US08/687,184 patent/US5803132A/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| US5542834A (en) | 1996-08-06 |
| US5803132A (en) | 1998-09-08 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued |