WO1995030854A1 - Tuyau metallique a enroulement helicoidal et a agrafe laterale radiale - Google Patents

Tuyau metallique a enroulement helicoidal et a agrafe laterale radiale Download PDF

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Publication number
WO1995030854A1
WO1995030854A1 PCT/US1995/005895 US9505895W WO9530854A1 WO 1995030854 A1 WO1995030854 A1 WO 1995030854A1 US 9505895 W US9505895 W US 9505895W WO 9530854 A1 WO9530854 A1 WO 9530854A1
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WO
WIPO (PCT)
Prior art keywords
pipe
spirally wound
approximately
recited
wound pipe
Prior art date
Application number
PCT/US1995/005895
Other languages
English (en)
Inventor
James R. Andre
Original Assignee
W.E. Hall Company
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by W.E. Hall Company filed Critical W.E. Hall Company
Publication of WO1995030854A1 publication Critical patent/WO1995030854A1/fr

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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
    • F16L9/00—Rigid pipes
    • F16L9/16—Rigid pipes wound from sheets or strips, with or without reinforcement
    • F16L9/165—Rigid pipes wound from sheets or strips, with or without reinforcement of 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
    • F16L11/00—Hoses, i.e. flexible pipes
    • F16L11/14—Hoses, i.e. flexible pipes made of rigid material, e.g. metal or hard plastics
    • F16L11/16—Hoses, i.e. flexible pipes made of rigid material, e.g. metal or hard plastics wound from profiled strips or bands

Definitions

  • the present invention relates generally to pipe products and more particularly to relatively small diameter spirally wound metal pipe products having a radially extending lock seam specifically sized, configured and spaced along the length of the pipe to optimize the load bearing capacity relative to the weight and cost thereof.
  • Pipe for use in sewers, storm drains, penstocks, culverts, and other low head applications is well know .
  • Corrugated metal pipe has been commonly used in such applications due to its relative low cost and light weight.
  • corrugated metal pipe exhibits poor fluid hydraulic characteristics and is susceptible to degradation when subjected to exposure to corrosive fluids and/or sewer fumes.
  • corrugated metal pipe is unsuitable for use in sanitary and/or sewer applications and is of a generally limited use in high hydraulic flow rate applications.
  • Concrete pipe has also been utilized in the prior art for culvert and similar applications since it is less susceptible to corrosion than metal pipes and has superior hydraulic characteristics.
  • concrete pipe is generally undesirable because it is heavier and more expensive than corrugated metal pipe.
  • the increased weight of concrete pipe makes it more difficult to handle and install and additionally increases the shipping cost associated therewith.
  • Such spiral ribbed pipe typically comprises helically wound sheet metal, typically formed of galvanized steel, having an axially oriented lock seam which joins adjacent edges of the sheet metal together.
  • Plural rectangular or deltoid shaped radially extending helical ribs are provided between the lock seams which significantly strengthen the pipe wall to withstand the substantial compression force encountered in underground burial applications.
  • the relative width, depth and spacing of such ribs is maintained within parameters which optimize fluid hydraulics and structural capabilities within the pipe. Due to the superior strength and improved hydraulic characteristics of Applicant's spiral ribbed pipe, such spiral ribbed pipe has gained widespread acceptance and has enjoyed substantial commercial success in the marketplace, becoming an industry standard for metal pipe products.
  • the cost efficiencies of such spiral ribbed pipe are typically optimized for pipe diameters between the range of 36 inches and 20 feet.
  • the rectangular or deltoid shaped ribs formed on such spiral ribbed pipe necessarily require a substantial quantity of sheet metal to be utilized in its formation.
  • Such sheet metal usage of course significantly contributes to the overall cost of the resultant pipe.
  • the sheet metal utilized to form the ribs comprise a smaller proportion of the total material utilized to form the pipe than at smaller diameters, i.e., less than 36 inches.
  • the use of Applicant's spiral ribbed pipe has generally been limited to applications requiring pipe diameters exceeding 36 inches.
  • plastic pipe has recently been introduced into the marketplace which has gained widespread acceptance.
  • Such prior art plastic pipe finds particular acceptance in those applications where a diameter of 24 inches or less is required.
  • plastic pipe has proven to structurally degrade over time due to the compressive forces exerted by over-burden in burial applications.
  • both the tensile strength and the modulus of elasticity of such plastic pipe rapidly decreases, i.e., downwardly creeps upon continuous application of the compressive forces associated in underground burial applications.
  • plastic pipe has been found to deform or even structurally collapse, thereby either partially or fully obstructing fluid flow therethrough. Due to this relatively rapid structural deterioration of plastic pipe, large quantities of such plastic pipe must frequently be excavated and replaced. As those skilled in the art will appreciate, such excavation and replacement of plastic pipe is extremely costly.
  • the present invention specifically addresses and alleviates the above-mentioned deficiencies associated in the prior art. More particularly, the present invention comprises a relatively small diameter (i.e., less than 36 inches) spirally wound metal pipe adapted for underground burial applications, specifically configured so as to optimize fluid hydraulics and the load bearing capacity thereof while minimizing the weight and cost thereof, i.e., minimizing the amount of material used in the construction thereof.
  • the small diameter spirally wound pipe of the present invention is fabricated from an elongate sheet of ductile material, e.g., sheet metal, having first and second edge portions which are shaped and crimped to form a radially extending lock seam.
  • the height of the lock seam (i.e., that distance which the lock seam extends radially outward from the pipe wall), the axial distance between adjacent lock seams, and the gauge of the sheet metal are all specifically selected in a manner which optimizes the load bearing capacity of the pipe while minimizing the weight and production cost thereof.
  • the load bearing capacity of the pipe of the present invention is dependent upon the gauge of the sheet metal utilized, the height of the radially extending lock seam, and the distance between adjacent locks seams. Since the amount of material utilized in the fabrication of the pipe is likewise dependent upon these factors, optimization of the load bearing capacity of the pipe in view of its weight produces a cost effective resultant pipe product. Thus, not only is the pipe of the present invention less expensive to fabricate than Applicant's spiral ribbed pipe, but because of its more efficient usage of thinner gauge sheet metal thus lighter weight, the pipe of the present invention is additionally less expensive to transport and install. As such, optimization provides substantial cost benefits which have heretofore been absent in the art.
  • a radially extending lock seam in the present invention provides increased strength and improved hydraulics in small diameter pipe superior to plastic pipe. It has been found that for pipe diameters of approximately 6 to 36 inches, particularly diameters between approximately 6 and 24 inches, a radially extending lock seam sized to extend between 3/8 and 1-1/2 inches from the pipe wall provides optimal strength for underground pipe applications formed from sheet material having a thickness of between approximately 16 and 22 gauge. Further, specific optimization have been achieved when the lock seams are spaced 6 inches apart for 20 gauge galvanized sheet steel, 9 inches apart for 18 gauge galvanized sheet steel, and 12 inches apart for 16 gauge galvanized sheet steel and when the lock seam has a height of approximately 1/2 inch in each instance.
  • the radially extending lock seam is formed by a pair of radially extending U-shaped member formed along opposite edges of the sheet metal.
  • the second U- shaped member is positioned so as to substantially envelop the first U-shaped member and is tightly crimped thereto in a fashion which securely locks the first and second portions together.
  • the first and second U-shaped members are preferably formed, i.e., bent in a common direction to result in a lock seam having four adjacent width of gauge sheet material.
  • the first U-member preferably includes a void formed near the base thereof and the second U-shaped member is preferably crimped such that a portion of the second U-shaped member extends into the void so as to increase the integrity of the lock seam.
  • the first and second U-shaped members may alternatively be bent in opposite directions from one another if desired.
  • the pipe of the present invention may additionally include one or more bowed ribs optionally formed in the sheet material to extend generally parallel to and intermediate adjacent lock seams. Such bowed ribs may reduce undesirable oil canning deformation and additionally tend to prevent denting of the pipe, wall during handling, transportation, and storage thereof.
  • the pipe of the present invention may include plural longitudinally extending ribs, preferably formed in a chevron or corrugation-like configuration between adjacent lock seams.
  • the longitudinally extending ribs also tend to prevent denting of the pipe during handling, transportation and storage thereof.
  • the longitudinally extending ribs may either be formed perpendicular to the length of the elongate sheet metal material from which pipe sections are formed, i.e., extend across the width thereof, or alternatively may be formed at an angle to the longitudinal axis of the elongate ductile material from which the pipe sections are formed, preferably at the helix angle of the pipe so as to be parallel to the longitudinal axis of the resultant pipe.
  • the pipe of the present invention is formed of galvanized sheet steel or aluminized steel type II sheet material such as that manufactured by ARMCO Steel of Middletown, Ohio.
  • aluminized steel type II sheet material such as that manufactured by ARMCO Steel of Middletown, Ohio.
  • various other ductile materials, particularly metals, are likewise suitable for use in the present invention.
  • the pipe of the present invention may be formed of polymer coated sheet steel such as that disclosed in pending United States Patent Application Serial Number 07/736,108, filed on July 26, 1991 entitled METAL PIPE WITH INTEGRALLY FORMED LINER AND METHOD OF FABRICATING THE SAME, the disclosure of which is expressly incorporated herein by reference.
  • the present invention contemplates the use of high performance invert coatings to prolong service life of the pipe.
  • Figure 1 is a perspective view of a first embodiment of the spirally wound metal pipe of the present invention, showing the radially extending lock seams and arcuate bowed ribs thereof;
  • Figure 2 is a cross-sectional view of the wall of the spirally wound metal pipe of Figure 1, showing the first and second U-shaped members which form the lock sea s and also showing a bowed rib formed in the wall thereof;
  • Figure 3a is an enlarged cross-sectional view of a lock seam of Figures 1 and 2;
  • Figure 3b is an enlarged cross-sectional view of an alternative lock seam construction;
  • Figure 4 is a cross-sectional view of a six inch wide ductile sheet material of Figures 1 and 2 having a single bowed rib formed therein;
  • Figure 5 is a cross-sectional view of a second embodiment of the present invention comprising nine inch wide ductile sheet material having two bowed ribs formed therein;
  • Figure 6 is a cross-sectional view of a third embodiment of the present invention comprising twelve inch wide ductile sheet material having three bowed ribs formed therein;
  • Figure 7 is a perspective view of a fourth embodiment of the spirally wound pipe of the present invention, showing the lock seams and longitudinally extending ribs thereof;
  • Figure 8 is a fragmentary perspective view of the elongate sheet of ductile material from which the spirally wound pipe of the present invention is formed, having chevron shaped longitudinal ribs formed therein;
  • Figure 9 is a cross-sectional view of the chevron shaped ribs of Figure 8 taken along lines 9-9 of Figure
  • Figure 10a is a fragmentary top view of elongate sheet material having chevron shaped ribs formed thereon perpendicular to the longitudinal axis thereof;
  • Figure 10b is a fragmentary top view of an elongate sheet of ductile material having chevron shaped ribs formed thereon at the helix angle of the pipe to be formed therefrom, such that the chevrons extend parallel to the longitudinal axis of a pipe section formed therewith as shown in Figure 7;
  • Figure 11 is a cross sectional view of an alternative corrugation-like configuration of the longitudinally extending ribs;
  • Figures 12 and 13 graphically compare the fill heights for the various profiles for 18 and 24 inch diameter pipes
  • Figures 14 and 15 plot pipe weights versus fill heights
  • Figure 16 is a schematic illustration of a pipe section utilizing the alternative configuration of the lock seam which is shown in Figure 3b;
  • Figures 17 and 18 graphically plot the efficiency of pipe sections in over-burden, i.e, burial conditions
  • Figure 19 is a listing of the calculated sectional properties for the three pipe profiles of the present invention and for standard contemporary corrugated pipe;
  • Figure 20 is a listing of the results of the fill height calculations for the three pipe profiles of the present invention and for standard contemporary corrugated pipe;
  • Figure 21 lists the calculated weights for 18 and 24 inch diameter pipe
  • Figures 22 and 23 tabulate effective properties for pipe having upstanding lock seams with intermediate arcuate shaped ribs
  • Figures 24-26 tabulate maximum pipe diameters and corresponding maximum over-burden fill heights.
  • Figure 27 tabulates the gross area of the various different pipe sections
  • Figure 28 tabulates the optimum pipe sections for over-burden, i.e., burial conditions
  • Figure 29 tabulates the optimum pipe sections for embankment conditions.
  • the spirally wound metal pipe of the present invention utilizes specific configurations of the height of a radially extending lock seam, axial distance between adjacent lock seams, and sheet metal gauge, so as to optimize the load bearing capacity of the pipe while simultaneously minimizing the amount of material required in the fabrication thereof.
  • both the cost and weight of the pipe of the present invention are minimized for a given load bearing capacity.
  • Specific configurations of spirally wound pipe have been found for relatively small pipe diameters, i.e., diameters between 6 and 36 inches which provide maximum load bearing capacity with minimum metal usage.
  • FIG. 1 there is shown a first embodiment of the small diameter spirally wound pipe of the present invention which is formed from an elongate sheet of ductile material 10a having a width of approximately six inches (dimension A of Figure 4). Opposite edges 12 and 14 of the ductile sheet material are joined during the pipe formation process upon a conventional pipe mill (not shown) to form a radially extending lock seam 16 which extends helically along the axial length of the pipe.
  • the lock seam 16 is formed by a radially extending first U-shaped member 18 formed along the first edge 12 and a radially extending second U-shaped member 20 formed along the second edge 14 of the sheet material 10a which cooperate with one another such that the second U-shaped member substantially envelops the first U-shaped member 18 and captures the first U-shaped member 18 therein.
  • the spirally wound pipe may further comprise at least one bowed or arcuate shaped rib 17 extending generally parallel to and formed intermediate adjacent lock seams 16.
  • the rib 17 bows outwardly, i.e., is convex as viewed from outside of the pipe so as to increase hydraulic efficiency.
  • the use of such bowed ribs additionally makes the spirally wound pipe more resistant to being dented, such as tends to occur during handling, shipping, and storage thereof.
  • the ductile sheet material 10a preferably comprises galvanized steel or aluminum type II sheet material having a gauge thickness of 16, 18, 20 or 22 gauge. However, those skilled in the art will recognize that various other materials are likewise suitable.
  • Fabrication of the spirally wound pipe of the present invention is effectuated in a generally conventional process wherein the ductile sheet material 10a is first removed from a roll (not shown) upon which it is supplied via a conventional uncoiler (not shown) .
  • the ductile material subsequently passes through one or more conventional profile roll formers (not shown) to form the first 18 and second 20 U-shaped members and the bowed rib 17.
  • the ductile material is then fed to a pipe mill (not shown) having a seam crimper and pipe former which simultaneously helically winds the ductile material into a length of pipe while crimping the second U-shaped member 20 over the first U-member 18 to form the lock seam 16.
  • the first U-shaped member 18 preferably includes a void 22 adjacent one end thereof.
  • a portion of the second U-member 20 is preferably crimped to extend into the void 22 formed by the first U-shaped member 18 to in effect form an abutment shoulder which prohibits disengagement of the U-shaped members and thereby securely lock adjacent edges of the sheet metal together.
  • the first 18 and second 20 U-shaped members are preferably bent in a common direction, (i.e., clockwise direction as illustrated in Figures 2 and 3).
  • the lock seam 16 extends between approximately three eighths and one and one half inches, preferably approximate one half inch, radially.
  • the first 18b and second 20b U-shaped members may alternatively be bent in opposite directions, rather than in the same direction as illustrated in Figure 3a.
  • a portion of the second U- shaped member 20b is then crimped into a void 22b formed by the first U-shaped member 18b.
  • the spirally wound pipe of the present invention comprises relatively small diameter spirally wound pipe (i.e., diameter between 6 and 36 inches) specifically sized and configured so as to optimize the load bearing capacity thereof while minimizing the weight and cost thereof. Calculations have provided optimal combinations of lock seam height, distance between adjacent lock seams, and sheet metal thickness. Three specific examples of such optimal configurations are illustrated in Figures 4-6 below.
  • the width, dimension A, of the sheet of ductile material is approximately 6 inches and one bowed rib 17 is optionally formed therein intermediate adjacent lock seams 16.
  • the lock seams 16 (defined by the first 18 and second 20 U-shaped members) are approximately 1/2 inch in height and the sheet metal of which the pipe is formed is 20 gauge in thickness.
  • the width, dimension B, of the sheet of ductile material is approximately 9 inches and two bowed ribs 17a and 17b are optionally formed therein intermediate adjacent lock seams 16.
  • the lock seams 16 (defined by the first 18 and second 20 U-shaped members) are approximately 1/2 in height and the sheet metal of which the pipe is formed is 18 gauge in thickness.
  • the width, dimension C, of the sheet of ductile material is approximately 12 inches and three bowed ribs 17a, 17b, and 17c are formed therein intermediate adjacent lock seams 16.
  • the lock seams 16 (defined by the first 18 and second 20 U-shaped members) are approximately 1/2 in height and the sheet metal of which the pipe is formed is 16 gauge in thickness.
  • longitudinally extending ribs 30 may be provided which extend parallel to the longitudinal axis of the pipe section.
  • the longitudinally extending ribs 30 are preferably formed to extend intermediate adjacent lock seams 16 of the pipe or may extend completely throughout the width of the sheet material as indicated by the phantom lines in Figure 8 and 10a.
  • the bowed ribs 17 of Figure 1 may additionally be utilized, in which case the longitudinally extending ribs 30 would extend intermediate adjacent lock seams 16 and/or bowed ribs 17.
  • Those skilled in the art will recognize that various combinations of bowed ribs 17 and longitudinally extending ribs 30 are suitable.
  • the longitudinally extending ribs 30 both increase the resistance to denting and also provide stress relief during the cold forming process so as to mitigate deformation of the ductile material, or oil canning, proximate the lock seams 16.
  • the longitudinally extending ribs 30 formed within the elongate sheet of ductile material 10 may be configured as a chevron shaped protrusion from the pipe section.
  • the distance between the peaks of adjacent chevrons, dimension D, is typically sized between approximately 1/2 and 3 inches, and preferably approximately 1 inch, while the height of each chevron, dimension E, is typically sized between 1/16 and 1/4 inch, preferably approximately 1/8 inch.
  • the longitudinally extending ribs 30 may be formed such that they are perpendicular to the longitudinal axis of the elongate sheet of ductile material utilized to form a pipe section.
  • the longitudinally extending ribs 30 are formed perpendicular to the longitudinal axis of the elongate sheet of ductile material, the resulting ribs of the pipe section are not parallel to the longitudinal axis of the pipe section, but rather are offset therefrom by an angle approximately equal to the helix angle of the pipe section.
  • the ribs 30 may be formed at an angle to the longitudinal axis of the elongate sheet of ductile material approximately equal to the helix angle of the finished pipe section.
  • the resulting longitudinally extending ribs 30 thereof are approximately parallel to the longitudinal axis of the finished pipe section.
  • the longitudinally extending ribs 30 may alternatively be formed as corrugations 32 formed in the elongate sheet of ductile material 10.
  • the center to center spacing i.e., distance between adjacent peaks, shown as dimension F, is typically between approximately 1/4 inch and 1 inch, and preferably approximately 1/2 inch.
  • the depth of the corrugations, shown as dimension G is between approximately 0.015 and 0.100 inch, preferably approximately .050 inch.
  • the decimal thicknesses for galvanized sheet steel are as follows: 0.036 inch (20 gauge), 0.046 inch (18 gauge), and 0.054 inch (16 gauge).
  • the decimal thicknesses for bare steel are as follows: 0.0326 inch (20 gauge), 0.0426 (18 gauge), and 0.536 (16 gauge).
  • effective section properties were calculated according to the provisions of the Design Specifications for Cold- Formed Steel Structural Members (American Iron and Steel Institute, 1986 and 1989).
  • fill heights i.e., over-burden height, for all of the profiles were calculated according to the provisions of ASTM Standard Practice A796 based on H20 live loads.
  • pipe weights were calculated for selected diameters to compare the various profiles.
  • the 6 x 1/2 provided the greatest effective area and moment of inertia for the resultant pipe product. Compared to the 1-1/2 x 1/4, the 6 x 1/2 profile had a smaller effective area but a greater moment of inertia. Thus, it should result in lower maximum fill heights but larger maximum pipe diameters.
  • Figure 20 shows the result of the fill height calculations.
  • pipe weights are plotted versus fill heights to allow a comparison of the profiles.
  • the required gauge is noted in the figure with a parenthesis to indicate where a trench installation is required.
  • Figure 14 shows that the least weight 18-inch diameter pipe would be the 1-1/2 x 1/4 profile followed by the 12 x 1/2, 9 x 1/2, and 6 x 1/2. All of these could be used in 20 gauge sheet stock, but the first two would require a trench installation.
  • the sheet stock gauge required increases and varies with the pipe profile.
  • Figure 15 illustrates that the least weight 24- inch diameter pipe would be the 20 gauge 6 x 1/2, followed by the 18 gauge 9 x 1/2, the 16 gauge 1-1/2 x 1/4, and the 16 gauge 12 x 1/2.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Rigid Pipes And Flexible Pipes (AREA)

Abstract

Un tuyau à enroulement hélicoïdal et de diamètre relativement peu important se compose d'une feuille allongée d'un matériau ductile dotée d'une configuration hélicoïdale, comprenant une agrafe latérale radiale (16) réunissant les parties marginales opposées de la feuille allongée. L'épaisseur calibrée du matériau ductile, la hauteur radiale de l'agrafe et la distance entre les agrafes adjacentes sont spécifiquement déterminées et configurées de façon à produire un tuyau dont la capacité de charge est optimalisée, tandis que son coût et son poids sont réduits au minimum. L'agrafe est formée par un premier élément radial en U (18), ménagé le long d'une première partie marginale de la feuille, et par un second élément radial en U (20), ménagé le long de la seconde partie marginale de la feuille, ces deux éléments étant sertis de façon que le second entoure sensiblement le premier afin de verrouiller ensemble les deux parties marginales.
PCT/US1995/005895 1994-05-10 1995-05-09 Tuyau metallique a enroulement helicoidal et a agrafe laterale radiale WO1995030854A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US24092494A 1994-05-10 1994-05-10
US08/240,924 1994-05-10

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Publication Number Publication Date
WO1995030854A1 true WO1995030854A1 (fr) 1995-11-16

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102016119604A1 (de) * 2016-10-14 2018-04-19 Schlemmer Gmbh Kabelummantelung und Kabelbaum
US20190128518A1 (en) * 2017-10-26 2019-05-02 Olympia Chimney Supply, Inc. Flexible Chimney Liner
EP3479917A1 (fr) * 2017-11-03 2019-05-08 Pacific Roller Die Company, Inc. Noyau tubulaire et procédé
US10933455B2 (en) 2016-07-07 2021-03-02 Pacific Roller Die Company, Inc. Tubular core and method
CN115316186A (zh) * 2022-09-09 2022-11-11 徐玮彬 土质边坡植树固坡匹配使用的圆管桩

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3435852A (en) * 1966-05-16 1969-04-01 Vulcan Australia Flexible ducting
US3865146A (en) * 1974-03-22 1975-02-11 Johns Manville Helically wound tubing and method of forming the same
US4029129A (en) * 1976-03-26 1977-06-14 Laffie Harper Helical pipe lock seam

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3435852A (en) * 1966-05-16 1969-04-01 Vulcan Australia Flexible ducting
US3865146A (en) * 1974-03-22 1975-02-11 Johns Manville Helically wound tubing and method of forming the same
US4029129A (en) * 1976-03-26 1977-06-14 Laffie Harper Helical pipe lock seam

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10933455B2 (en) 2016-07-07 2021-03-02 Pacific Roller Die Company, Inc. Tubular core and method
DE102016119604A1 (de) * 2016-10-14 2018-04-19 Schlemmer Gmbh Kabelummantelung und Kabelbaum
US20190128518A1 (en) * 2017-10-26 2019-05-02 Olympia Chimney Supply, Inc. Flexible Chimney Liner
EP3479917A1 (fr) * 2017-11-03 2019-05-08 Pacific Roller Die Company, Inc. Noyau tubulaire et procédé
CN115316186A (zh) * 2022-09-09 2022-11-11 徐玮彬 土质边坡植树固坡匹配使用的圆管桩
CN115316186B (zh) * 2022-09-09 2023-10-03 徐玮彬 土质边坡植树固坡匹配使用的圆管桩

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