Pipes and tubular conduits – Flexible – Braided – interlaced – knitted or woven
Reexamination Certificate
1999-01-29
2001-10-16
Brinson, Patrick (Department: 3752)
Pipes and tubular conduits
Flexible
Braided, interlaced, knitted or woven
C138S127000, C138S141000, C138S137000, C138S153000
Reexamination Certificate
active
06302150
ABSTRACT:
TECHNICAL FIELD
The subject invention relates to hose construction. More specifically, the subject invention relates to a method for constructing a hose assembly having an inner fluorocarbon polymer liner and reinforcing layer thereabout.
BRIEF DESCRIPTION OF THE RELATED ART
Hose assemblies for conveying fuel and other corrosive materials are well known in the art. Such assemblies are exposed to a variety of fuel mixtures, fuel additives, and caustic materials in addition to being exposed to extreme temperatures. Thus, such hose assemblies must be resistant to chemical, environmental, and physical degradation as a result of chemical exposure, environmental exposure to heat, and physical degradation resulting from bending and repeated movement or forces applied to the assembly.
Polymeric fluorocarbon materials such as polytetrafluoroethylene possess the requisite chemical and temperature resistant properties for most fuel hose applications. Unfortunately, polymeric fluorocarbon materials exhibit relatively poor tensile and hoop strengths. As a consequence, such fluorocarbon materials are prone to kinking. Such kinking remains permanent and provides a continual resistance to the fluid flow through the hose assembly. Moreover, as a result of a fluorinated material's low tensile strength, attachment or securing of coupling members to the hose assembly is substantially compromised.
Various approaches have been described for offering additional strength to a polymeric fluorocarbon liner. One approach involves braiding fibers about the inner fluorocarbon liner. The braided fibers offer additional strength to the fluorocarbon liner resulting in a hose assembly that resists kinking. Examples of such approaches are disclosed in U.S. Pat. No. 5,124,878 issued Jun. 23, 1992, U.S. Pat. No. 5,142,782, issued Sep. 1, 1992, and U.S. Pat. No. 5,192,476 issued Mar 9, 1993, all assigned to the assignee of the subject invention.
The hose assembly described in the '878 patent includes an inner fluorocarbon polymeric liner, a braided reinforcing layer disposed about the exterior of the inner liner, and is characterized by including an organic polymeric material dispersed in the reinforcing layer which connects the reinforcing layer to the inner liner thereby providing a hose assembly which is stronger and more kink resistant.
Both the '782 and '476 patents disclose methods for producing a hose assembly of the type shown in the '878 patent. The '782 patent discloses a method of making a lightweight hose assembly including the steps of extruding an inner liner, applying a braided reinforcing material having gaps extending therethrough about the inner liner. The inner liner and the braided layer are then passed through a reservoir containing a solution of a fluorocarbon polymer. After the solvent is removed, the fluorocarbon polymer coating is dispersed throughout the braided layer and bonds the braided layer to the inner fluorocarbon liner.
The '476 patent discloses a method of forming a hose assembly in which an inner liner of a fluorocarbon material is extruded and then passed through a reservoir containing a dispersion including a fluorocarbon polymer material. A reinforcing layer is then braided about the exterior of the inner liner to form a braided layer having the dispersion thereabout such that the dispersion penetrates the interstitial spaces of the braided layer. Subsequently, the assembly is heated to remove the solvent and the braided reinforcing layer is then bonded to the fluorocarbon polymer inner liner.
The methods disclosed in the '782 and '476 patents yield a highly desirable and excellent performing hose assembly, however, the steps of applying the fluorocarbon polymer dispersion to the inner liner can allow some of the fluorocarbon polymer dispersion to enter the interior of the hose where it may cause problems when the hose assembly is used in a desired application. Additionally, the hose assemblies discussed above preferably utilize non-melt extrudable fluorocarbon polymers for the inner liner. These non-melt extrudable fluorocarbon polymer materials typically possess a higher permeation rate than do melt extrudable fluorocarbon polymer materials. That is, the ability of volatile fluids or gases to escape through the wall of the inner liner is greater with non-melt extrudable fluorocarbon based hose assemblies. Additionally, non-melt extrudable fluorocarbon materials are not as easily adapted to recycling or reuse of the material as are melt-extrudable fluorocarbon materials.
An additional example of strengthening an inner fluorocarbon liner with an outer liner while also increasing flexibility is shown in U.S. Pat. No. 3,023,787 to Phillips et al. The Phillips et al. patent discloses a convoluted hose assembly having a fluorocarbon inner liner constructed of many layers of helically wrapped Teflon® tape. Convoluted hoses are typically employed because they provide flexibility to a fluorocarbon hose assembly, however, convoluted hose assemblies have inherent weaknesses. A reinforcing strip consisting of reinforcing fibers coated with a plastic material is wrapped about the inner layer to provide additional strength to the assembly due to the inherent weakness of wrapped convoluted core construction. In its final assembly, a metal braid is applied to the outside of the hose assembly to impart greater strength.
Hose assemblies of the type described in the Phillips et al. patent have several inherent drawbacks. First, because the inner liner is formed by helically wrapping layers of a fluorocarbon tape, it requires a greater amount of fluorocarbon material to be utilized in order to construct the inner liner which adds to both the cost of constructing the hose assembly and to the labor intensity of constructing the hose assembly. Other drawbacks associated with hoses of the type disclosed in the Phillips et al. patent includes failure of seams created by helically wrapping layers of Teflon® tape. These failures occur due to inherent weaknesses in bonding the seams created by the overlapping layers of tape which, under internal pressures and prolonged movement are prone to leakage or to bursting. In addition, the seams create undulations within the inner liner which cause disruption in the flow of liquids therein which could give rise to increased electrical charge buildup within the hose.
Therefore, it would be desirable to have a method for constructing a fluorocarbon hose assembly which eliminates the necessity for liquid fluorocarbon polymer dispersions in order to bond reinforcing layers to a fluorocarbon liner.
Further, it would be desirable to have a hose assembly which includes a polymeric fluorocarbon inner liner which is resistant to kinking while additionally possessing greatly increased bending properties while maintaining the overall integrity of the hose assembly.
SUMMARY OF THE INVENTION AND ADVANTAGES
In accordance with the present invention, there is provided a method for constructing a hose assembly. The method includes the steps of disposing a reinforcing layer having interstitial spaces extending therethrough about a tubular inner liner and dispersing the tubular inner lines into the interstitial spaces and bonding the reinforcing layer to the inner liner.
Additionally, accordingly to the present invention, there is provided a hose assembly including an extruded, smooth bore tubular inner liner including a melt extrudable polymeric fluorocarbon material having an external surface and a reinforcing layer having gaps extending therethrough disposed about the external surface. The external surface of the inner liner is dispersed into the reinforcing layer and bonds the reinforcing layer to the external surface of the inner liner.
REFERENCES:
patent: Re. 35527 (1997-06-01), Martucci
patent: 323149 (1885-07-01), Holt
patent: 334951 (1886-01-01), Holt
patent: 2690769 (1954-10-01), Brown
patent: 3023787 (1962-03-01), Phillips et al.
patent: 4092897 (1978-06-01), Lalikos et al.
patent: 4104095 (1978-08-01), Shaw
patent: 419
Martucci Norman S.
Mathew Boney A.
Brinson Patrick
Kohn & Associates
Teleflex Fluid Systems
LandOfFree
Hose assembly / and method for making same does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Hose assembly / and method for making same, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Hose assembly / and method for making same will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2606639