GB761670A - Improvements in or relating to fire hose - Google Patents

Abstract

Fire hose having a thin impervious lining of polyvinyl chloride is made by introducing into the jacket of the hose a tube of gelled polyvinyl chloride composition containing between 35 per cent and 65 per cent by weight of polyvinyl chloride of high molecular weight, a suitable plasticizer, and not more than 10 per cent of other matter, and having specified characteristics of viscosity, ultimate tensile strength and elongation-at-break, into the jacket of the hose, the tube having an external diameter considerably less than the internal diameter of the jacket and a wall thickness substantially exceeding the thickness of the intended lining, and thereafter admitting fluid under pressure to the interior of the tube to expand it into contact with the jacket, and heating the tube to bond it to the jacket. The tube may be expanded by the admission of cold air under pressure, and hot air or steam then gradually introduced, and the fluid pressure maintained while the tube cools. In an example, a hose of 2.5 inches bore is treated internally with a polyvinyl chloride-to-fabric adhesive, by introducing the latter into one end of the jacket of the hose and then introducing this end into the nip of a pair of driven rollers. The jacket was then inflated and the adhesive allowed to dry. An extruded polyvinyl chloride tube of 1.5 inches outside diameter and .025 inches wall thickness was drawn into the jacket by means of a cord, and air at room temperature and 45 lbs. per sq. in. pressure introduced into the tube; when the tube and jacket were fully stretched, the air was replaced, without releasing the pressure, by hot air at 108 DEG C. to 110 DEG C., and the heating maintained for 20 minutes, after which the pressure was released. Suitable polyvinyl chloride compositions are quoted. Specification 538,455 [Group XXVIII] is referred to.