HOSE CONSTRUCTION AND METHOD OF MAKING SAME

摘要

1477433 Curing a corrugated, reinforced pipe DAYCO CORP 28 April 1975 [11 July 1974] 17570/75 Heading B5A [Also in Division F2] A method of making a hose construction having axially spaced convolutions comprises forming an elastomeric base tube 15, applying a reinforcing layer 20 concentrically around said base tube, applying an elastomeric cover tube 16 around said layer semi-curing said assembly, placing said semi-cured assembly in a mold device having axially spaced convolutions comprising its wall means, and final forming and final curing said semi-cured assembly by urging said assembly against said wall means while subjecting said assembly to a controlled environment to form said axially spaced convolutions in said .hose construction defined by alternating crests and troughs; the crests andtroughs produced are of a predetermined wall thickness due to said semi-curing step preceding said final forming step. The base tube is formed by an extrusion process and the reinforcing layer is knitted around the said tube which is supported by a pressurized fluid. The cover tube is extruded over the reinforcing layer using a cross-head extruder. The semi-curing is achieved at a temperature of about 275‹ F. for a time of about 10 minutes and the final curing step is achieved using internal steam at a temperature of about 335‹ F. for a time of about. 10 minutes with the mold surface being heated to about 315‹ F. A helical spring wire (27) Fig. 2 (not shown) is inserted inside the hose as a reinforcing member. Preferably the layer 20 is applied as a single layer of 2200 denier rayon in a knitted lockstitch with 8-9 courses per inch, or from any suitable material including natural fibres and synthetic fibres, including fibreglass. The elastomeric material could be a natural or a synthetic rubber. Such materials include natural rubber, rubber-like butadiene-styrene and butadiene-acrylonitrile copolymers, neoprene, other rubber-like butadiene polymers and copolymers, and copolymers and terpolymers based on ethylene and propylene. Vulcanizable rubbers are compounded so that they may be cured or vulcanized under heat using sulphur or other known agents, depending upon the specific material.