Hydraulic barriers use laser drilled holes

Protecting high value components from random surges of contaminants, in hydraulic, fuel and lubrication systems in aerospace applications, a new safety screen design has been adopted by MOD vehicles

Typically, wire mesh and sintered screen filters are the in-line devices, which offer protection by cleansing whole systems.

However, a highly resilient and more targeted alternative is available from Lee Products, the pioneers of the design and manufacture of miniature precision fluid control components.

The Hi-Bar series of safety screens from Lee Products are designed to complement the role of filters by providing optimum security and protection for individual high-value components in aerospace, defense and other critical applications.

These one-piece barriers are available in steel or aluminium and feature laser-drilled holes, a process which results in extremely accurate and evenly spaced holes of between 75 and 400 microns diameter and from 35 up to 37,000 holes per metal screen.

Fully clogged Hi-Bar screens can withstand pressures up to 518 bar without collapse and allow bi-directional oil flow.

One recent example of the successful application of these safety screens is Parker Hydraulics use of Lee safety screen in its revamped PM125 hydraulic pump, which is incorporated into the MoD fleet of armoured recovery vehicles, based upon the Chieftain tank design.

Hi-Bar safety screens are available in a number of variations including flange and boss mounted options offering benefits such as rugged, high strength performance, no burst or collapse at 7500 psid fully clogged, high contamination carrying capacity for maximum protection, combined with low lohm, high-flow capacity.

Editors Note: A lohm is Lee Products simple system of defining the fluid resistance of Lee hydraulic components.

Just as OHM is used in the electrical industry, Lee find that they can use a "liquid OHM", or "lohm" to good advantage.

As the lohm figure increases, so does the resistance of the valve or fluid obstruction increase.

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