Process of PTFE Steel Lined Hydraulic Hose

Ordinary PTFE pipe will rupture when subjected to a pressure of about 40kg/cm2. When they are combined with steel wires, their pressure resistance is greatly improved. The maximum working pressure abroad reaches 700kg/cm2. Research shows that the compressive strength and impulse strength of the hose is not only related to the strength of the steel wire but also related to the braid angle. When the braid angle is 54°44″ in single-layer braiding, the steel wire does not stretch under internal pressure, the length and diameter of the hose do not change, and the pressure resistance is the best.

When used as a hose in the hydraulic system of the aviation industry, in order to prevent the inner tube from electrostatic breakdown during the flow of hydraulic oil, a small amount of conductive carbon black must be added to the PTFE inner tube. However, studies have found that adding carbon black does not completely prevent static electricity from discharging through the tube wall, and increases voids. In the 1960s, Atta’s company manufactured a composite tube body, that is, the inner layer of the tube is a uniform mixture of a certain proportion of conductive carbon black and PTFE, and the outer layer of the tube is pure PTFE. The inner layer of this type of tube has axial conductivity, so it can eliminate static electricity and prevent seepage.

The process: inner resin (contains conductive carbon black), outer resin → compact → pushing → drying → cooling → inspection → weaving → fitting → inspection.

PTFE steel wire composite hoses are mainly used for hydraulic systems, air-conditioning systems, fuel systems, and lubricating oil systems on aircraft. In the civil industry, it is suitable for rubber, plastic, pharmacy, clothing, shipbuilding, automobiles, machine tools, motors, diesel engines, papermaking, and other industries as soft connectors for hydraulic, vapor pressure, and steam delivery.