What is rubber hydraulic hose?
Rubber hydraulic hose is made of a combination of various materials from rubber, polyurethane, polyethylene, nylon and natural or synthetic fibers. Hoses are built based on application and performance. Hydraulic hoses consist of an inner tube, one or more layers of reinforcement, and an outer cover. Each constituent should be selected with the intended application in mind. Typical operating and performance parameters include the size, temperature, fluid type, pressure-holding capacity and environment, to name a few. The inner tube contains the fluid and keeps it from leaking to the outside. The type of hydraulic fluid generally dictates the tube material. Usually it is nitrile or synthetic rubber for petroleum-based hydraulic oil. The cover protects the reinforcement layer. One consideration when determining the cover material is resistance to attack from outside influences like chemicals, salt water, steam, UV radiation and ozone. Common cover materials include nitrile, neoprene and PVC, among others.
Rubber hydraulic hoses are a common and important component of countless industrial and mobile machines. It serves as the plumbing that routes hydraulic fluid between tanks, pumps, valves, cylinders and other fluid-power components. And if specified properly and not overly abused, hose can work trouble-free for hundreds of thousands of pressure cycles.
Rubber hydraulic hose is often referred to by the type of reinforcement: “braided” or “spiral.” In either case, reinforcement layers are tightly wrapped upon the tube with special winding machines. Applying the cover over the reinforcement completes the hose.
Braided hoses are constructed, as the name implies, by cross-braiding alternating rows of textile or synthetic fibers or steel wires at specific opposing angles around the tube. Most low-pressure rubber hoses have a textile-braided construction and either rubber or woven-textile covers. They’re generally for pressures to about 1,000 psi and typically handle hydraulic fluids, diesel fuel, lubricating oil and ethylene glycol. They’re also commonly used for water or compressed air.
Braided steel-wire hose comes with one or two reinforcement layers. When two layers are used, a rubber layer separates the two. Common types, such as widely used SAE 100 R1 and SAE100 R2 versions, are often referred to as “1-wire” and “2-wire” hose, respectively. These products are considered medium-pressure hoses, for use from about 1,000 to 5,000 psi—depending on the number of reinforcement layers and the size. They are used on many types of industrial machinery and construction equipment, as well as on heavy-duty trucks and fleet vehicles.
Spiral-wound hydraulic hose is for demanding, high-pressure applications, generally from about 4,000 to 8,000 psi. They have alternating, tightly wound spiral layers of high-tensile steel wire. The wires in the second layer are laid at an opposing angle to the first, and the pattern repeats for each subsequent layer.
Two types are 4-wire and 6-wire versions, based on the number of reinforcing layers. Four-layer spiral wound hydraulic hose is extremely strong and is common in high-pressure, large-diameter hose assemblies. Six-wire hose is used for even more-extreme requirements. Inner-diameter sizes tend to run from about 0.38-in. to 2.0 to 3.0-in. ID, depending on the manufacturer and specific type.