GB1572323A - Hose construction - Google Patents

Description

(54) HOSE CONSTRUCTION (71) We, PARKER HANNIFIN CORPORA TION, a corporation organised and existing under the laws of the State of Ohio, United States of America, of 17325 Euclid Avenue, Cleveland, Ohio 44112, United States of America, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: - This invention relates to flexible composite hose.

Flexible hose used in automotive air conditioning systems is usually composed of a nylon core tube, a nylon reinforcement layer disposed about the core tube and a nylon outer sheath. Nylon exhibits excellent refrigerant retention qualities and relatively high strength. Thus, the resulting hose structure does retain the refrigerant passing therethrough and exhibits a relatively high burst strength. Nylon, however, is not resistant to battery acid and permits some moisture permeation. This lack of resistance of nylon to moisture permeation is especially detrimental to the operation of the air conditioning system since moisture will cause corrision in the system and may render the system inoperative due to the internal formation of ice. Nylon's lack of resistance to battery acid is also very detrimental since such acid will cause deterioration of the hose in a comparatively short period of time.

The present invention provides a solution to the aforementioned problem of lack of resistance of a hose to moisture and battery acid. This is accomplished by using polyethylene rather than nylon for the outer sheath of the hose.

The invention thus provides a flexible composite hose for conveying fluids under pressure comprising a core tube formed from Nylon 6/6-6 material, one or more layers of a synthetic polymeric fibre reinforcement material disposed about said core tube, and a polyethylene outer sheath disposed about said synthetic polymeric fibre reinforcement layer(s).

Polyethylene has a high resistance to moisture permeation and greatly retards moisture from passing through the wall of the hose into the air conditioning system, thus minimizing the formation of rust and corrosion in the system. Polyethylene also exhibits excellent resistance to oils and chemicals, and thus contact of the polyethylene outer sheath with battery acid will not cause deterioration of the hose structure. Combining this polyethylene outer sheath with a nylon core tube and a nylon reinforcement layer results in a flexible high strength air conditioning system hose which is resistant to the refrigerant passing therethrough, moisture infusion, and to battery acid, oil, and grease which might come into contact with the hose.

The drawing is a side view, broken away in successive structural layers, of a preferred hose made in accordance with the present invention.

The drawing shows a hose 10 having a core tube 12, one or more layers 14 of reinforcement material, and an outer sheath 16.

The core tube 12 is formed from plasticized Nylon 6/6-6 copolymer material.

Nylon 6/6-6 exhibits much greater resistance to permeation by halogenated refrigerants than materials heretofore used for the core tube, such as Nylon 11, synthetic rubber, or the like, and thus is ideally suited for applications where refrigerant retention is imperative. In addition, Nylon 6/6-6 is flexible resulting in a relatively flexible hose structure.

Reinforcement layer 14 is composed of synthetic filaments such as nylon, Dacron (Trade Mark), rayon, or Kevlar (Trade Mark) yarn. In the preferred embodiment of the invention, Nylon 6/6 yarn is used and may be braided or spirally wound about core tube 12. The inner surface of reinforcement layer 14 is bonded to the core tube 12 but not to outer sheath 16.

If more than one layer of reinforcement material is used, the first layer is bonded to the core tube, but each succeeding layer is not bonded to the immediately adjacent reinforcement layer or to the outer sheath 16. Any suitable method may be used for bonding the reinforcement layer 14 to core tube 12, such as solvents or adhesives.

The use of Nylon 6/6 yarn for the reinforcement layer 14 gives the resulting hose structure a moderately high burst strength while maintaining hose flexibility.

In addition, even though the hose is relatively flexible, the use of Nylon 6/6 for the reinforcement layer also increases the kink resistance of the hose.

Outer sheath 16 is formed from polyethylene material. In the preferred embodiment of the invention, a jacket of polyethylene is extruded over reinforcement layer 14 and pressed into the interstices of the braid and between the braid fibers to form a mechanical interlock with reinforcement layer 14. Polyethylene has a significantly higher resistant to moisture permeation than materials heretofore used for the outer sheath, such as nylon, Hytrel, polyurethane, or the like. Thus, the use of polyethylene for the outer sheath greatly retards the passage of moisture through the wall of the hose into the air conditioning system, thus minimizing the formation of ice and corrosion in the system.

Polyethylne is also relatively impervious to battery acid, oils, grease, and other contaminants normally found in the engine compartment, and thus contact of the hose with these contaminants will not result in hose deterioration. In addition, the use of polyethylene having a relatively high melting point, in excess of 250"F, and good stress crack resistance insures the integrity of the hose in an engine compartment installation. All of the aforementioned advantages of polyethylene makes it ideally suited for use as the outer sheath for a hose in an automotive air conditioning system.

Variations of the present invention will be apparent to those having ordinary skill in the art and the invention is limited only by the scope of the following claims.

WHAT WE CLAIM IS: - 1. A flexible composite hose for conveying fluids under pressure comprising a core tube formed from Nylon 6/6-6 material, one or more layers of a synthetic polymeric fibre reinforcement material disposed about said core tube, and a polyethylene outer sheath disposed about said synthetic polymeric fibre reinforcement layer(s).

2. A flexible composite hose as defined in claim 1 wherein said synthetic polymeric fibre reinforcement material is Nylon 6/6 and said one or more layers of reinforcement material is in the form of a braid disposed about said core tube.

3. A flexible composite hose as defined in claim 1 wherein said synthetic polymeric fibre reinforcement material is Nylon 6/6 and said one or more layers of reinforcement material is in the form of a spiral wrap disposed about said core tube.

4. A flexible composite hose as defined in any preceding claim wherein said polyethylene outer sheath is comprised of polyethylene material extruded over said one or more layers of synthetic polymeric reinforcement material.

5. A flexible composite hose as defined in any preceding claim wherein said polyethylene material is received within the interstices of said one or more reinforcement layers forming a mechanical interlock between said outer sheath and said one or more reinforcement layers.

6. A flexible composite hose for conveying fluids under pressure, substantially as hereinbefore described with reference to the drawing.

7. A flexible composite hose according to any preceding claim, in an automotive air conditioning system.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (7)

**WARNING** start of CLMS field may overlap end of DESC **. Mark) yarn. In the preferred embodiment of the invention, Nylon 6/6 yarn is used and may be braided or spirally wound about core tube 12. The inner surface of reinforcement layer 14 is bonded to the core tube 12 but not to outer sheath 16. If more than one layer of reinforcement material is used, the first layer is bonded to the core tube, but each succeeding layer is not bonded to the immediately adjacent reinforcement layer or to the outer sheath 16. Any suitable method may be used for bonding the reinforcement layer 14 to core tube 12, such as solvents or adhesives. The use of Nylon 6/6 yarn for the reinforcement layer 14 gives the resulting hose structure a moderately high burst strength while maintaining hose flexibility. In addition, even though the hose is relatively flexible, the use of Nylon 6/6 for the reinforcement layer also increases the kink resistance of the hose. Outer sheath 16 is formed from polyethylene material. In the preferred embodiment of the invention, a jacket of polyethylene is extruded over reinforcement layer 14 and pressed into the interstices of the braid and between the braid fibers to form a mechanical interlock with reinforcement layer 14. Polyethylene has a significantly higher resistant to moisture permeation than materials heretofore used for the outer sheath, such as nylon, Hytrel, polyurethane, or the like. Thus, the use of polyethylene for the outer sheath greatly retards the passage of moisture through the wall of the hose into the air conditioning system, thus minimizing the formation of ice and corrosion in the system. Polyethylne is also relatively impervious to battery acid, oils, grease, and other contaminants normally found in the engine compartment, and thus contact of the hose with these contaminants will not result in hose deterioration. In addition, the use of polyethylene having a relatively high melting point, in excess of 250"F, and good stress crack resistance insures the integrity of the hose in an engine compartment installation. All of the aforementioned advantages of polyethylene makes it ideally suited for use as the outer sheath for a hose in an automotive air conditioning system. Variations of the present invention will be apparent to those having ordinary skill in the art and the invention is limited only by the scope of the following claims. WHAT WE CLAIM IS: -

1. A flexible composite hose for conveying fluids under pressure comprising a core tube formed from Nylon 6/6-6 material, one or more layers of a synthetic polymeric fibre reinforcement material disposed about said core tube, and a polyethylene outer sheath disposed about said synthetic polymeric fibre reinforcement layer(s).

2. A flexible composite hose as defined in claim 1 wherein said synthetic polymeric fibre reinforcement material is Nylon 6/6 and said one or more layers of reinforcement material is in the form of a braid disposed about said core tube.

3. A flexible composite hose as defined in claim 1 wherein said synthetic polymeric fibre reinforcement material is Nylon 6/6 and said one or more layers of reinforcement material is in the form of a spiral wrap disposed about said core tube.

4. A flexible composite hose as defined in any preceding claim wherein said polyethylene outer sheath is comprised of polyethylene material extruded over said one or more layers of synthetic polymeric reinforcement material.

5. A flexible composite hose as defined in any preceding claim wherein said polyethylene material is received within the interstices of said one or more reinforcement layers forming a mechanical interlock between said outer sheath and said one or more reinforcement layers.

6. A flexible composite hose for conveying fluids under pressure, substantially as hereinbefore described with reference to the drawing.

7. A flexible composite hose according to any preceding claim, in an automotive air conditioning system.