Hose

A wide range of standard and proprietary hoses have evolved to meet most every industrial and mobile-equipment need. Modern hydraulic hoses vary widely in terms of pressure ratings, temperature ranges, and materials, but all consist of three basic components: Tube, reinforcement, and cover.
The inner tube, made from synthetic-rubber compounds and composites, must be chemically compatible with a wide range of petroleum-based and biodegradable fluids. Special compounds may be required to handle fire-resistant fluids. The tube must also resist corrosion and deterioration and the effects of high or low temperatures.

Reinforcement allows the hose to handle fluid pressures and pressure spikes, and prevents premature hose bursts when properly used. It determines the working pressure of the hose. Hoses with low working pressures normally use textile-fiber reinforcement, while those handling higher pressures generally use high-strength steel wire.

Steel-reinforced hoses, in turn, fall into two categories: Braid and spiral. Wire-braided hose handles working pressures to 6, 000 psi, depending on size, with one or two braid layers. Spiral hose, which generally handles high pressures in larger diameters, has wire spiraled around the tube on a bias, with successive layers laid at opposing angles. There are typically four or six layers of steel reinforcement. In braid and spiral hose, rubber layers separate layers of steel wrap to ensure good adhesion throughout the hose wall.
The cover protects the tube and reinforcement from heat, abrasion, and corrosion, as well as environmental deterioration from heat, cold, UV light, and ozone. Covers are made from synthetic rubber, fiber braids, or a fabric wrap, depending on the application.