Axial Piston Fixed A4FO

The A4FO pump is designed to be used in open circuits. The axial piston unit must be filled with hydraulic fluid and air bled during commissioning and operation. This must also be observed following a longer standstill as the axial piston unit may empty via the hydraulic lines.

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Particularly in the installation position „drive shaft upwards“, filling and air bleeding must be carried out completely as there is, for example, a danger of dry running. For sizes 22 and 28, the pump housing is internally connected to the suction chamber. A separate drain line from the housing to the reservoir is not needed. A drain line is required for sizes 71 to 500. If a shared drain line is used for several units, make sure that the relevant case pressure is not exceeded. The shared drain line must be dimensioned to ensure that the maxi-mum permissible case pressure of all connected units is not exceeded in any operational circumstances, particularly at cold start. If this is not possible, separate drain lines must be laid if necessary.

To achieve favourable noise values, decouple all connecting lines using elastic elements and avoid above-reservoir installation. In all operating conditions, the suction lines and the drain lines must flow into the reservoir below the minimum fluid level. The permissible suction height hS results from the overall loss of pressure. However, it must not be higher than hS max = 800 mm. The minimum suction pressure at port S must not fall below 0,8 bar absolute during operation either. When designing the reservoir, ensure that there is adequate spacing between the suction line and the drain line. This minimizes oil turbulence and carries out degassing, which prevents the heated hydraulic fluid from being sucked directly back in again.

Installation position :
See the following examples 1 to 8. Additional installation positions are available upon request.

Below-reservoir installation (standard)
Below-reservoir installation is when the axial piston unit is installed outside of the reservoir below the minimum fluid level.