Method of and apparatus for impregnating fabric reinforcement structures with a liquid impregnant

Claim 3

A method according to claim 1 wherein said reinforcement structure is made of textile material.

Claim 4

A method according to claim 1 wherein said reinforcement structure is made of non-textile material.

Claim 5

A method according to claim 3 wherein said liquid elastomer-forming composition comprises components which react and set to form a polyurethane.

Claim 6

A method according to claim 3 wherein said liquid elastomer-forming composition comprises a functional group-tipped liquid butadiene/acrylonitrile copolymer rubber and an epoxy resin.

Claim 7

A method according to claim 3 wherein the viscosity of the liquid elastomer-forming reaction composition is less than 10 NS/m 2 at the impregnating temperature.

Claim 8

A method according to claim 6 wherein the viscosity of the liquid elastomer-forming reaction composition is less than 5 NS/m 2 at the impregnating temperature.

Claim 9

A method according to claim 7 wherein the viscosity of the liquid elastomer-forming reaction composition is less than 1 NS/m 2 at the impregnating temperature.

Claim 10

A method according to claim 1 wherein said reinforcement structure is tubular and internally supported on a mandrel.

Claim 11

A method according to claim 9 wherein the reinforcement structure is applied to a tubular inner liner of elastomeric material which is internally supported on a mandrel.

Claim 12

A method according to claim 10 wherein the reinforcement structure comprises one or more layers of reinforcement material.

Claim 13

A method according to claim 11 wherein the or each reinforcement layer comprises a braid.

Claim 14

A method according to claim 11 wherein the or each reinforcement layer comprises a spiral winding.

Claim 15

A method according to claim 11 wherein the or each reinforcement layer has an at least 60% coverage.

Claim 16

A method according to claim 14 wherein the or each reinforcement layer has an at least 75% coverage.

Claim 17

A method according to claim 11 wherein a plurality of reinforcement layers are applied successively without any intermediate layer of material.

Claim 18

A method according to claim 11 wherein a plurality of reinforcement layers are applied with a material permeable to the impregnant provided between successive reinforcement layers.

Claim 19

A method according to claim 1 or 2 wherein the cure of the impregnant is aided by the application of heat.

Claim 20

Apparatus for impregnating an elongate fabric reinforcement structure with an impregnant which is liquid at impregnation temperature and chemically reacts to form an elastomer, said apparatus comprising an applicator head having a substantially vertical elongate through bore for the passage of said reinforcement structure to be impregnated, a supply inlet opening into the lower end of said bore adapted for connection to a source of said liquid impregnant for supplying said liquid impregnant to said inlet and means within said bore for effecting a seal with said reinforcement structure passing through said bore, said applicator head being constructed and arranged such that in use said reinforcement structure is advanced downwards through said bore and said liquid impregnant supplied to said bore forms a column within said bore in which said impregnant entering said column is continuously displaced upwards along the length of said column and said reinforcement structure is continuously advanced in the opposite direction.

Claim 21

Apparatus for impregnating an elongate fabric reinforcement structure with an impregnant which is liquid at impregnation temperature and chemically reacts to form an elastomer, said apparatus comprising an applicator head having a substantially vertical elongate through bore for the passage of said reinforcement structure to be impregnated, a supply inlet opening into the lower end of said bore adapted for connection to a source of said liquid impregnant for supplying said liquid impregnant to said inlet and means within said bore for effecting a seal with said reinforcement structure passing through said bore, said applicator head being constructed and arranged such that in use said reinforcement structure is advanced downwards through said bore and said liquid impregnant supplied to said bore forms a column within said bore in which said impregnant entering said column is continuously displaced upwards along the length of said column and said reinforcement structure is continuously advanced in the opposite direction.

Claim 22

Apparatus according to claim 19 wherein said seal means is provided adjacent to and downstream of the position at which said supply inlet opens into said bore.

Claim 23

Apparatus according to claim 19 wherein said seal means comprises a flexible ring member made of elastomeric material defining a central opening through which the reinforcement structure passes.

Claim 24

Apparatus according to claim 21 wherein said seal means is provided with a plurality of leakage openings.

Claim 25

Apparatus according to claim 22 wherein said leakage openings are defined by circumferentially spaced cuts in the elastomeric material defining the periphery of said central opening.

Claim 26

Apparatus according to claim 19 wherein said applicator head includes a fluid chamber surrounding said bore.

Claim 27

Apparatus according to claim 19 wherein the dimensions of said bore are such as to provide limited clearance between the outer surface of said reinforcement structure and said bore over at least that portion of the bore which contains said column of impregnant.

Claim 28

Apparatus according to claim 25 wherein said clearance is from 1 to 2 mm.

Claim 29

Apparatus according to claim 26 wherein said clearance is greater than 2 mm in the vicinity of said supply inlet.

Claim 30

The apparatus of claim 19 in which the volume of said bore available for the liquid impregnant is such that the average residence time of said impregnant in the bore is significantly less than the setting time of the impregnant under conditions prevailing in the applicator head.