In brief
A hydraulic hose is a flexible pressure line consisting of inner tube, reinforcement and cover that carries hydraulic fluid between moving components.
Contents
What is Hydraulic hose?
Hydraulic hoses connect components that move or vibrate relative to each other, such as cylinders on presses, slewing drives in conveying equipment or tools on injection moulding machines. An oil-resistant inner tube carries the medium, a reinforcement of steel wire braid or spiral absorbs the pressure, and the cover protects against abrasion, ozone and weathering. With crimped fittings, this becomes a hose assembly.
Key ratings are nominal size, maximum operating pressure, temperature range, minimum bend radius and media compatibility. Common types are described in EN 853 (braid-reinforced), EN 856 (spiral-reinforced) and EN 857 (compact braided hoses); SAE types are also widespread. Fittings differ in connection form, for example sealing cone with O-ring or thread with sealing cone.
Hoses age even without visible damage. Causes of failure are falling below the bend radius, torsion, chafing, heat and pressure peaks. A burst can endanger people through escaping oil; regular inspection and timely replacement are therefore mandatory. For maintenance, it pays to keep a register of all hose assemblies with installation location, type, length and installation date. Inspection dates and replacement needs can then be planned from it.
In practice: maintenance and procurement
The layline printed on the hose and the fitting designation contain the most important data for reproduction. In addition, the overall length, connection forms at both ends, offset angle for elbow fittings and the manufacturing date of the hose assembly are needed.
Synonyms and abbreviations: hydraulic hose assembly · high-pressure hose · hose assembly · 2SN hose
Frequently asked questions
What information is needed for a new hydraulic hose?
The hose type or standard, nominal size, operating pressure, overall length including fittings, connection form and thread at both ends, the offset angle for elbow fittings, as well as medium and temperature are needed. The layline on the hose and the stamping on the fitting provide most of the data. Photos of both ends avoid misunderstandings.
How long may a hydraulic hose be used?
Hydraulic hose assemblies are subject to ageing and may not be used indefinitely. Rules of the German statutory accident insurance institutions and manufacturer information contain recommendations on the period of use, which are adjusted according to the stress involved. The decisive factor is the operator’s risk assessment; visible damage requires immediate replacement, regardless of age.
What do 1SN, 2SN or 4SH mean for hydraulic hoses?
The codes designate hose types from European standards. SN types are reinforced with one or two layers of steel wire braid and are intended for medium pressures. SP and SH types have several layers of steel wire spiral and withstand higher pressures and pressure impulses. The permissible pressure also depends on the nominal size.
How can a damaged hydraulic hose be recognised?
Warning signs are cracks or blisters in the cover, exposed braid, kinks, deformation, damp patches and leakage at the fitting. A displaced or corroded fitting also indicates a problem. Such hose assemblies should be replaced immediately.