US20040007278A1

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Publication number: US20040007278A1
Application number: US10/164,850
Authority: US
Inventors: Robert Williams
Original assignee: Individual
Current assignee: Individual
Priority date: 2002-06-06
Filing date: 2002-06-06
Publication date: 2004-01-15

Abstract

A conduit defining a continuous conduit passage extending from a first opening to a second opening includes a plurality of flexible, tubular, corrugated sections, each defining at least a portion of the conduit passage therethrough. A plurality of tubular, non-corrugated sections are merged with at least one of the corrugated sections and define at least a portion of the conduit passage therethrough. The plurality of corrugated sections and the plurality of non-corrugated sections are arranged in alternating relation.

Description

FIELD OF THE INVENTION

The present invention relates to conduits and pipes and, more particularly, to conduits and pipes for forming bends.[0001]

BACKGROUND OF THE INVENTION

Polymeric pipes are commonly used for transporting water and other fluids. Pipes formed of polyvinyl chloride (PVC) and chlorinated polyvinyl chloride (CPVC) may be preferred in many applications because of their performance characteristics and relatively low cost. PVC and CPVC pipes are rigid and typically are difficult to bend without kinking. As a result, typically fittings must be used to accommodate more than nominal bends. Alternatively, heat may be used to soften a pipe for bending. However, heat bending may reduce the performance characteristics (e.g., the pressure rating) of the pipe if the pipe wall on the outside of the bend is stretched thin. As a consequence of the foregoing problems, flexible piping material such as cross-linked polyethylene (PEX) and other polyolefin-based pipes have been employed in applications where PVC or CPVC piping might otherwise be preferred. Moreover, PEX and other polyolefin-based pipes may also suffer from insufficient flexibility.[0002]

SUMMARY OF THE INVENTION

According to embodiments of the present invention, a conduit defining a continuous conduit passage includes a flexible, tubular, corrugated section defining at least a portion of the conduit passage therethrough. At least the corrugated section is formed of CPVC.[0003]

According to further embodiments of the present invention, a conduit defining a continuous conduit passage includes a flexible, tubular, corrugated section defining at least a portion of the conduit passage therethrough. At least the corrugated section is formed of cross-linked polyethylene (PEX).[0004]

According to further embodiments of the present invention, a conduit defining a continuous conduit passage extending from a first opening to a second opening includes a plurality of flexible, tubular, corrugated sections, each defining at least a portion of the conduit passage therethrough. A plurality of tubular, non-corrugated sections is provided. Each of the non-corrugated sections merges with at least one of the corrugated sections and defines at least a portion of the conduit passage therethrough. The plurality of corrugated sections and the plurality of non-corrugated sections are arranged in alternating relation.[0005]

According to further embodiments of the present invention, a conduit system includes first and second substantially rigid conduits. A third conduit is interposed between the first and second conduits. The third conduit includes a flexible, tubular, corrugated section. At least the corrugated section is formed of CPVC.[0006]

According to further embodiments of the present invention, a conduit includes first and second substantially rigid conduits and a third conduit interposed between the first and second conduits. The third conduit includes a flexible, tubular, corrugated section. At least the corrugated section is formed of PEX.[0007]

According to method embodiments of the present invention, a method for forming a conduit includes extruding a tubular pre-form of PVC, CPVC, or PEX. Thereafter, a corrugated section is formed in the pre-form.[0008]

According to further method embodiments of the present invention, a method for forming a conduit includes extruding a tubular pre-form of a thermoplastic. A corrugated section is formed in the pre-form. A non-corrugated section is formed in the pre-form such that the non-corrugated section is merged with the corrugated section.[0009]

According to further method embodiments of the present invention, a method for forming a conduit system includes providing a first conduit including a flexible, tubular, corrugated section. At least the corrugated section is formed of CPVC. Second and third substantially rigid conduits are coupled to opposed ends of the first conduit. The corrugated section is bent to form a bend between the second and third conduits.[0010]

According to further method embodiments of the present invention, a method for forming a conduit system includes providing a first conduit including a flexible, tubular, corrugated section defining at least a portion of the conduit passage therethrough, wherein at least the corrugated section is formed of PEX. Second and third substantially rigid conduits are coupled to opposed ends of the first conduit. The corrugated section is bent to form a bend between the second and third conduits.[0011]

According to further method embodiments of the present invention, a method for forming a conduit system includes providing a corrugated conduit defining a continuous conduit passage and including a flexible, tubular, corrugated section defining a first portion of the conduit passage therethrough. The corrugated section is formed of a thermoplastic. A tubular, non-corrugated section is merged with the corrugated section at an end of the corrugate section. The non-corrugated section defines a second portion of the conduit passage. The corrugated conduit is installed in a building structure such that the corrugated conduit provides fluid communication between a supply of potable water and a dispenser.[0012]

Objects of the present invention will be appreciated by those of ordinary skill in the art from a reading of the figures and the detailed description of the preferred embodiments which follow, such description being merely illustrative of the present invention.[0013]

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a conduit according to embodiments of the present invention;[0014]

FIG. 2 is a cross-sectional view of the conduit of FIG. 1 taken along the line[0015]2-2;

FIG. 3 is a side view of a conduit system including the conduit of FIG. 1;[0016]

FIG. 4 is a side view of a conduit assembly according to embodiments of the present invention;[0017]

FIG. 5 is a side view of a conduit system including a portion of the conduit assembly of FIG. 4;[0018]

FIG. 6 is a schematic view of an apparatus for forming and packaging a conduit assembly according to embodiments of the present invention; and[0019]

FIG. 7 is a block diagram representing method embodiments of the present invention for forming the conduit of FIG. 1 and the conduit assembly of FIG. 4.[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention now is described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.[0021]

With reference to FIGS. 1 and 2, a[0022]

conduit

100 according to preferred embodiments of the present invention is shown therein. Theconduit100 may be used to form aconduit system17 as shown in FIG. 3. As discussed in more detail below, two or more of theconduits100 may be integrally formed and connected so as to form aconduit assembly10 as shown in FIG. 4.

As best seen in FIG. 2, the[0023]

conduit

100 includes a tubular, flexiblecorrugated section130 and a pair of integral, relatively rigid, tubular, non-corrugated

sections

112 and114 merged with and extending from opposed ends of thecorrugated section130. Theconduit100 defines

opposed end openings

140A and140B and a throughpassage140 extending between and fluidly connecting the

openings

140A and140B.

Portions

142,144 and146 of thepassage140 are defined within the

sections

112,130 and114, respectively. The overall length L1 of theconduit100 is preferably between about 14 and 52 inches.

The non-corrugated[0024]

sections

112,114 are preferably adapted to engage conventional piping of common or standard dimensions. The length L2 of each of the

non-corrugated sections

112 and114 is preferably at least about 2 inches. The nominal inner diameter D1 of the

sections

112 and114 is preferably at least 0.489 inch, and more preferably between about 0.489 and 2.149 inches. Each of the

non-corrugated sections

112,114 preferably has a nominal thickness T1 of at least 0.068 inch, and more preferably between about 0.068 and 0.113 inch.

The[0025]

corrugated section

130 includes a plurality of annular,concentric walls135.Adjacent walls135 are joined alongupper folds132 andlower folds134 to form a series of corrugations.

The distance W[0026]1 of adjacentupper folds132 is preferably between about 0.335 and 0.551 inch. The distance W2 between adjacentlower folds134 is preferably between about 0.335 and 0.551 inch. Thewalls135 preferably have a nominal thickness T2 of at least 0.068 inch, and more preferably between about 0.068 and 0.113 inch. The lower folds134 preferably have a thickness T3 of at least 0.068 inch, and more preferably between about 0.068 and 0.113 inch. The upper folds132 preferably have a thickness T4 at least 0.068 inch, and more preferably of between about 0.068 and 0.113 inch. The corrugations preferably have a height D2 (i.e., the radial distance from a givenupper fold132 to a given lower fold134) of between about 0.281 and 0.469 inch. The nominal inner diameters of thelower folds134 are preferably the same as the nominal inner diameter D1 of the

non-corrugated sections

112,114. Preferably, the wall thickness is substantially uniform along the full length L1 of theconduit100. The length L3 of thecorrugated section130 is preferably between about 10 and 40 inches, and more preferably of between about 10 and 12 inches.

The[0027]

conduit

100 may be formed of any suitable polymeric material. According to certain preferred embodiments, theconduit100 is formed of CPVC. When formed of CPVC, theconduit100 is particularly well suited for use in pressurized hot water piping. Preferably, the material of theconduit100 has a modulus of elasticity of at least 360,000 psi and, more preferably, of between about 360,000 and 400,000 psi.

When formed of CPVC, the[0028]

conduit

100 preferably has a burst pressure of at least 250 psi at 180° F. When formed of PVC, theconduit100 preferably has a burst pressure of at least 630 psi at 73° F. Preferably, theconduit100 is constructed so as to meet or exceed ASTM Standard F1970-01, revision 2001, when formed of CPVC. Preferably, theconduit100 is constructed so as to meet or exceed ASTM Standard D2241-00, revision 2000, when formed of PVC. Preferably the conduit meets or exceeds ASTM Standard D1784-99A.

With reference to FIG. 3, the[0029]

conduit

100 may be used in the following manner to form aconduit system17. The

non-corrugated sections

112 and114 are inserted into the open ends of substantially rigid

tubular conduits

12 and14, respectively. The

conduits

12,14 may be of conventional construction and are preferably formed of PVC or CPVC. Thecorrugated section130 is bent to form abend16 between the

conduits

12 and14. It will be appreciated that the

conduits

12 and14 may be coupled to the

sections

112 and114 by other techniques.

When formed of CPVC, the[0030]

corrugated section

130 is preferably adapted to bend at an angle of at least 90 degrees relative to straight while maintaining a burst pressure of at least 250 psi at 180° F. When formed of PVC, thecorrugated section130 is preferably adapted to bend at an angle of at least 90 degrees relative to straight while maintaining a burst pressure of at least 630 psi at 73° F.

With reference to FIG. 4, a plurality of the[0031]

conduits

100 may be serially connected to form anintegral conduit assembly10. More particularly, theconduit assembly10 includes a series ofcorrugated sections130 and extended,non-corrugated sections110 arranged in alternating relation. Eachnon-corrugated section110 corresponds to the

non-corrugated sections

112 and114 ofadjacent conduits100.

A[0032]

single conduit

100 may be provided by cutting theconduit100 from theconduit assembly10. Alternatively, two or more of theconduits100 may be cut from theconduit assembly10 such that the two ormore conduits100 are still connected or theconduit assembly10 may be used as a whole. For example, with reference to FIG. 5, aconduit assembly10A consisting of twoconduits100 joined at an extendednon-corrugated section110 is shown therein. Thenon-corrugated section112 of thefirst conduit100 and thenon-corrugated section114 of thesecond conduit100 are coupled to the

conduits

12 and14, respectively. Each of thecorrugated sections130 is bent to form a combinedbend19. Conduit systems according to the present invention may be formed using conduit assemblies consisting of greater than twoconduits100, for example, to form sharper bends without overstressing the conduit assembly.

According to preferred methods of the present invention and with reference to FIGS. 6 and 7, the[0033]

conduit

100 orconduit assembly10 may be formed using the following methods and anapparatus160. Suitable raw material (e.g., CPVC compound in pellet or powder form) is provided to anextruder162. Theextruder162 is preferably a twin screw extruder. A continuous,tubular conduit pre-form102 is extruded from the extruder162 (Block170). Preferably, the pre-form102 has substantially the same inner and outer diameters as the

non-corrugated sections

112 and114. The pre-form102 is preferably generated at a rate of at least 15 feet per minute.

The pre-form[0034]102 is directed to acorrugator166, which is preferably in-line with theextruder162. Preferably, the pre-form102 extends continuously from theextruder162 to thecorrugator166. Thecorrugator166 forms the corrugations of thecorrugated section130 in the pre-form102 (Block172). More particularly, thecorrugator166 intermittently engages the pre-form102 to form thecorrugated sections130 at spaced apart locations along the length of the pre-form102 such that uncorrugated sections corresponding to thesections110 remain between thecorrugated sections130. Preferably, the pre-form102 extends along substantially a single axis all the way from the exit of theextruder162 to the downstream end of the portions of thecorrugator166 that engage the pre-form102 (e.g., the mold dies). Preferably, the pre-form102 is maintained at a temperature in the range of between about 350 and 450° F. from theextruder162 to thecorrugator166.

The[0035]

corrugated sections

130 are formed by thecorrugator166 while the pre-form102 is heat-softened (i.e., in its plasticized condition). Preferably, the pre-form102 is still heat softened (i.e., plasticized) from the heat of theextruder162. Auxiliary heaters (e.g., in the corrugator166) may be used to soften the pre-form102 for the corrugating step. Preferably, the sections of the pre-form102 in which the corrugations are formed are at a temperature of between about 350 and 450° F. during the step of molding the corrugations into the pre-form102. Preferably, the pre-form is cooled in thecorrugator166 such that the exiting tube has a temperature of between about 125 and 175° F.

The[0036]

corrugator

166 may form thecorrugated sections130 using a combination of a mold and a vacuum. The vacuum is provided in the mold to draw the pre-form102 into the mold dies, the mold dies having the shape of the desiredcorrugated section130.

The[0037]

corrugator

166 may form thecorrugated sections130 using a combination of a mold and pressure or blow molding. A pressurized fluid, for example, air, is provided inside the pre-form102 to prevent or limit collapse of the pre-form102 as the mold dies are compressed about the pre-form102. The mold dies have the shape of the desiredcorrugated section130.

A[0038]

continuous conduit assembly

10 is thereby produced from thecorrugator166. After cooling, theconduit assembly10 may thereafter be packaged in desired fashion (Block174). Theconduit assembly10 may be wound onto aroll168 to form apackage11. Alternatively, theconduit assembly10 may be cut to desired lengths including one ormultiple conduits100.

The conduits and conduit assemblies of the present invention may be used to convey potable water. The conduit and conduit assemblies may convey the potable water from a suitable source of potable water such as a water storage container or a water supply pipe (e.g., a municipal water line) to a suitable dispenser such as a faucet. Preferably, such conduit formed of CPVC is installed in a building structure to convey potable pressurized hot water (i.e., water having a temperature in the range of between about 120 and 160° F.). Such conduit formed of PVC may be installed in the building structure to convey potable pressurized cold water (i.e., water having a temperature in the range of between about 40 and 80° F.). The building structure may be a residential or commercial structure.[0039]

According to further embodiments of the present invention, conduits and integral conduit assemblies as described above may be formed of suitable thermoplastic materials other than PVC or CPVC. Such conduits and conduit assemblies may be formed in the same manner and otherwise of the same construction as described above with regard to the[0040]

conduit

100 and theconduit assembly10. The selected thermoplastic material is preferably well-suited for use in pressurized water piping. It is particularly contemplated that conduits and conduit assemblies as described above may be formed of cross-linked polyethylene (PEX) in place of PVC or CPVC. While PEX may have significant inherent flexibility, the corrugated sections provide additional flexibility to facilitate installation and longevity.

The foregoing is illustrative of the present invention and is not to be construed as limiting thereof. Although a few exemplary embodiments of this invention have been described, those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiments without materially departing from the novel teachings and advantages of this invention. Accordingly, all such modifications are intended to be included within the scope of this invention. Therefore, it is to be understood that the foregoing is illustrative of the present invention and is not to be construed as limited to the specific embodiments disclosed, and that modifications to the disclosed embodiments, as well as other embodiments, are intended to be included within the scope of the invention.[0041]

Claims

That which is claimed is:

1. A conduit defining a continuous conduit passage and comprising:

a) a flexible, tubular, corrugated section defining at least a portion of the conduit passage therethrough;

b) wherein at least the corrugated section is formed of CPVC.

2. The conduit ofclaim 1 further including:

a) a tubular, non-corrugated section merged with the corrugated section at an end of the corrugated section;

b) wherein the non-corrugated section defines a second portion of the conduit passage.

3. The conduit ofclaim 2 wherein the non-corrugated section is formed of CPVC.

4. The conduit ofclaim 2 wherein the non-corrugated section has a nominal wall thickness of at least 0.068 inch.

5. The conduit ofclaim 2 wherein the non-corrugated section has a nominal inner diameter of at least 0.489 inch.

6. The conduit ofclaim 2 wherein the non-corrugated section has a length of at least about 2 inches.

7. The conduit ofclaim 2 including:

a) a second tubular, non-corrugated section merged with the corrugated section at a second end of the corrugated section;

b) wherein the second non-corrugated section defines a third portion of the conduit passage.

8. The conduit ofclaim 7 including a second tubular, corrugated section merged with the second non-corrugated section at an end of the second non-corrugated section opposite the first corrugated section.

9. The conduit ofclaim 1 wherein the corrugated section has a nominal wall thickness of at least 0.068 inch.

10. The conduit ofclaim 1 wherein the corrugated section has a nominal inner diameter of at least 0.489 inch.

12. The conduit ofclaim 1 wherein the corrugated section has a length of between about 10 and 40 inches.

13. The conduit ofclaim 1 wherein the conduit has a burst pressure of at least 250 psi at 180° F.

14. The conduit ofclaim 1 wherein the conduit meets or exceeds ASTM F1970-01, revision 2001.

15. The conduit ofclaim 1 wherein the conduit is formed of CPVC having a modulus of elasticity of at least 360,000 psi.

16. A conduit defining a continuous conduit passage and comprising:

b) wherein at least the corrugated section is formed of cross-linked polyethylene (PEX).

17. The conduit ofclaim 16 further including:

18. The conduit ofclaim 17 wherein the non-corrugated section is formed of PEX.

19. The conduit ofclaim 17 wherein the non-corrugated section has a length of at least about 2 inches.

20. The conduit ofclaim 17 including:

21. The conduit ofclaim 20 including a second tubular, corrugated section merged with the second non-corrugated section at an end of the second non-corrugated section opposite the first corrugated section.

22. A conduit defining a continuous conduit passage extending from a first opening to a second opening and comprising:

a) a plurality of flexible, tubular, corrugated sections each defining at least a portion of the conduit passage therethrough; and

b) a plurality of tubular, non-corrugated sections each merged with at least one of the corrugated sections and defining at least a portion of the conduit passage therethrough;

c) wherein the plurality of corrugated sections and the plurality of non-corrugated sections are arranged in alternating relation.

23. The conduit ofclaim 22 wherein each of the corrugated sections and the non-corrugated sections is formed of a thermoplastic.

24. The conduit ofclaim 23 wherein each of the corrugated sections and the non-corrugated sections is formed of CPVC.

25. The conduit ofclaim 24 wherein the conduit meets or exceeds ASTM F1970-01, revision 2001.

26. The conduit ofclaim 23 wherein each of the corrugated sections and the non-corrugated sections is formed of PVC.

27. The conduit ofclaim 26 wherein the conduit meets or exceeds ASTM D2241-00, revision 2000.

28. The conduit ofclaim 23 wherein each of the corrugated sections and the non-corrugated sections is formed of PEX.

29. The conduit ofclaim 22 wherein the conduit is formed of PVC or CPVC having a modulus of elasticity of at least 360,000 psi.

30. A conduit system comprising:

a) first and second substantially rigid conduits; and

b) a third conduit interposed between the first and second conduits, wherein:

the third conduit includes a flexible, tubular, corrugated section; and

at least the corrugated section is formed of CPVC.

31. A conduit system comprising:

a) first and second substantially rigid conduits; and

b) a third conduit interposed between the first and second conduits, wherein:

the third conduit includes a flexible, tubular, corrugated section; and

at least the corrugated section is formed of PEX.

32. A method for forming a conduit, the method comprising:

a) extruding a tubular pre-form of PVC, CPVC, or PEX; and

b) forming a corrugated section in the pre-form.

33. The method ofclaim 32 wherein the pre-form is formed of CPVC.

34. The method ofclaim 32 wherein the pre-form is formed of PVC.

35. The method ofclaim 32 wherein the pre-form is formed of PEX.

36. The method ofclaim 32 wherein the conduit is formed to meet or exceed ASTM D1794-99A.

37. The method ofclaim 32 wherein the step of forming the corrugated section is performed in-line with the step of extruding the pre-form.

38. The method ofclaim 32 wherein said step of forming a corrugated section includes forming corrugations in the pre-form while the pre-form is plasticized.

39. The method ofclaim 38 wherein said step of forming a corrugated section includes:

a) compressing the pre-form with at least one mold adapted to form the corrugations; and

b) pressurizing an interior passage of the pre-form with a pressurizing fluid while the mold is compressing the pre-form to limit displacement of walls of the pre-form into the interior passage.

40. The method ofclaim 38 wherein said step of forming a corrugated section includes:

a) positioning at least one mold adjacent the pre-form, the mold being adapted to form the corrugations; and

b) applying a vacuum to draw at least a portion of the pre-form into the mold to thereby form the corrugations.

41. A method for forming a conduit, the method comprising:

a) extruding a tubular pre-form of a thermoplastic;

b) forming a corrugated section in the pre-form; and

c) forming a non-corrugated section in the pre-form such that the non-corrugated section is merged with the corrugated section.

42. The method ofclaim 41 wherein the pre-form is formed of CPVC.

43. The method ofclaim 41 wherein the pre-form is formed of PVC.

44. The method ofclaim 41 wherein the pre-form is formed of PEX.

45. A method for forming a conduit system, said method comprising:

providing a first conduit including a flexible, tubular, corrugated section defining at least a portion of the conduit passage therethrough, wherein at least the corrugated section is formed of CPVC;

coupling second and third substantially rigid conduits to opposed ends of the first conduit; and

bending the corrugated section to form a bend between the second and third conduits.

46. The method ofclaim 45 wherein the first conduit includes a second corrugated section connected to the first corrugated section by an integral non-corrugated section, and further including bending the second corrugated section to form the bend.

47. The method ofclaim 46 including cutting the first conduit from a conduit assembly including a third corrugated section, said step of cutting including separating the first conduit from the third corrugated section.

48. A method for forming a conduit system, said method comprising:

providing a first conduit including a flexible, tubular, corrugated section defining at least a portion of the conduit passage therethrough, wherein at least the corrugated section is formed of PEX;

49. The method ofclaim 48 wherein the first conduit includes a second corrugated section connected to the first corrugated section by an integral non-corrugated section, and further including bending the second corrugated section to form the bend.

50. The method ofclaim 49 including cutting the first conduit from a conduit assembly including a third corrugated section, said step of cutting including separating the first conduit from the third corrugated section.

51. A method for forming a conduit system, the method comprising:

a) providing a corrugated conduit defining a continuous conduit passage and including:

a flexible, tubular, corrugated section defining a first portion of the conduit passage therethrough, the corrugated section being formed of a thermoplastic; and

a tubular, non-corrugated section merged with the corrugated section at an end of the corrugate section, the non-corrugated section defining a second portion of the conduit passage; and

b) installing the corrugated conduit in a building structure such that the corrugated conduit provides fluid communication between a supply of potable water and a dispenser.

52. The method ofclaim 51 wherein the corrugated section is formed of CPVC.

53. The method ofclaim 51 wherein the corrugated section is formed of PVC.

54. The method ofclaim 51 wherein the corrugated section is formed of PEX.

55. The method ofclaim 51 wherein the step of installing includes bending the corrugated section to form a bend.

56. The method ofclaim 51 further including connecting at least one substantially rigid conduit to the corrugated conduit such that the rigid conduit also provides fluid communication between the supply of potable water and the dispenser.