A hydraulic hose is different than a rubber hose in many ways. This type of hose contains a braided stainless steel sleeve inside of its rubber outer covering. This sleeve allows the hydraulic hose to withstand great amounts of pressure. The couplings of a hydraulic hose are crimped on with a special machine to create a fitting that will withstand the high pressures under which the system operates.
Many hydraulic hoses are rubber coated with a woven or braided nylon or stainless steel sleeve on the exterior as well as on the interior of the hose. The outer protective covering prevents the hose from becoming cut or chaffed when coming in contact with another part of the machine. Often a hydraulic hose will also contain a flexible Teflon inner tube at the center.
A typical hydraulic system will consist of at least two hoses. One is for high pressure while the other is a low-pressure return hose. The hoses connect to a hydraulic pump and carry the hydraulic fluid to an apparatus that is hydraulically operated, such as a hydraulic cylinder. The pump is either electrically driver or driven by a vehicle's engine.
Many hydraulic hose fittings are of the quick-disconnect type. This allows a hydraulic hose to be removed and replaced without having to bleed the entire system of air. Many farming and construction implements utilize this type of quick-disconnecting fitting to aid in the changing of tools and power providers. For example, a hydraulic jack hammer can be used on a crane and then switched to be used on a skid steer type of tractor, such as a Bobcat.
Due to the reinforcing layers of a hydraulic hose, this type of hose is much stiffer and heavier than a non-hydraulic version. The hoses must be constructed to fit an application with slow, generous bends. Typical right angle bends are completed using a hard line fitting bent to the proper angle required. Many hydraulic hoses consist of multiple sections of flexible hose and hard lines connected in series.
Hydraulic hoses must also be able to withstand heat. Hydraulic systems often build up heat as the process of pumping the hydraulic fluid and operating the implements generate a great deal of heat. Hydraulic cooling systems are often incorporated into a hydraulic system. Resembling a small radiator or a finned cylinder, the cooling unit prevents the fluid from reaching a dangerous operating temperature.