Hose and Pipe

Rigid Pipes (Steel Pipes).

Because of its high performance, steel-galvanized pipes are widely used in hydraulic pipe installations, particularly in the systems applying static and high pressures.  When selecting a pipe, the thickness of the pipe wall must be taken into consideration as it determines the pipe tension.  The pipes with thicker wall can accommodate a higher inner pressure.  Therefore, it is important to consider the size of the pipe and the system pressure when replacing a hydraulic pipe with a new one.  Use the pipe of a correct size or in accordance with the design.  The procedure for replacing a pipe is as follows:

  • Replace the old pipe with a new one of similar design and material.
  • If possible, avoid any sharp bending in construction.
  • All of the components must be joined using threaded joint in anticipation of the pressure and tension working on the pipe.
  • The new pipe must be free from corrosion and slags.

The assembly of a hydraulic system must be done in such away for easy dismantlement and efficient  use of space

Notes:

BENAR = CORRECT

SALAH = INCORRECT

Hoses (flexible pipes)

Hoses used in hydraulic systems are commonly coated with fibres, electrometric material or braided wires.  Hydraulic hoses are widely used in hydraulic systems because they are easy to install and are able to absorb shocks and engine vibrations.  However, installation of hoses is much more expensive than that of rigid pipes.

Hoses are commonly used in industry and automotive assemblies in accordance with SAE specification.  Two types of hydraulic hose that are most commonly used include that with single braided wires (SAE 100R1) and that with double braided wires (SAE 100R2).

In selecting a hydraulic hose, the following factors must be taken into consideration:

  • The size of the hose must match the quantity of fluid.
  • The pressure and the temperature inside the system.

The selection of hose pressure rating is based on the operating pressure of the system.  The hose must be able to resist the maximum peak pressure during normal operation of the system.  The hydraulic oil temperature must also be taken into consideration when selecting a hose.

Hose Fittings

There are two types of fitting commonly used in a hydraulic system, namely:

  1. Connectors – a part of a hose having a socket and a nipple.
  2. Adaptor – a separated part that connects the fitting to another pipe connector

Recommended Installation

If the hoses are considered expensive, steel pipes are preferable because they are reusable and easy to repair.  The hoses are suitable for short distance installation and are able to absorb shocks.

Hydraulic fittings should be made of steel.  The fittings used for inlets, return lines and outlets can be made of formable iron.

Correct installation is important to prevent leakage, contamination and noisy operation.

Table: hose length tolerance for hydraulic system according to DIN 20066

Table : Hose materials and operating temperature according to DIN 20066

Table: Hose total length for a certain radius according to DIN 20066.

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