Using, structure and crimping hydraulic hoses
Hydraulic hoses, also called cables, pipes or tubes, are one of most inconspicuous but at the same time one of most important components of almost each hydraulic system. Two special metal fittings fixed to both ends are crucial parts of each hose.
Using hydraulic hoses as well as their construction - with particular reference to fittings - are briefly discussed below.
Using hydraulic hoses
Hydraulic hoses have a wide range of applications. They constitute crucial elements of all machines and devices in which fluids (oil, water, liquid solutions) or even compressed gases are a working substance. Hoses join various elements of hydraulic systems and enable proper functioning of the whole machines. They are widely used in industrial, building, mining machines, road, aerial and agricultural vehicles etc.
Depending on applications hoses differ mainly in diameters, permissible temperature and pressure working limits as well as in structure e.g. in a number of layers (braids).
Hydraulic hoses construction
A hydraulic hose usually has a circular cross-section. As it has to stand rapid changes of very high pressure its structure has to be very robust.
Stiff hydraulic hoses are made of metal. A typical good quality flexible hydraulic hose is usually built of:
● inner tube
● reinforcement layer (layers) i.e. braid (braids)
● outer casing
● fittings.
An inner tube is usually of synthetic rubber. It carries hydraulic fluid, is very smooth so flow resistance is realtively low.
Reinforcement layers are of textile materials or steel. They can be braided or spiral wound and reinforce the inner tube.
An outer casing is also crafted mainly of synthetic rubber. It protects the entire hose against mechanical or environmental damage.
Metal fittings differ in diameter and length of thread. They have to be firmly fixed to hose ends to prevent leakage.
Crimping hydraulic hoses
Fixing of fittings is called ‘crimping hoses’. Against all appearances, crimping hydraulic hoses is not a very complicated process. Crimping is aimed at joining all elements in an inextricable system.
First of all, one should cut a hose to a desired length. Then, suitable metal fittings are inserted into hose ends. Next, appropriate metal collets are put on fittings. Finally, collets are crimped on fittings.
To crimp hoses one can use special crimping machines. They can be operated manually or automatically. In some cases, even handheld crimping pliers will do.
If a fitting is damaged, one can cut off a hose end with this fitting, or cut through collets to remove the fitting, and fix another one. To avoid frequent damage, it is recommended to choose hoses according to their intended use and adjusted to operating conditions.
Summary
To sum up, one would say that practically any hydraulic system will not work well without hydraulic hoses. For this reason, proper crimping hoses is very important and has to be done very carefully by professionalists.