If possible, the reservoir design should be such that any entrained air is released before the fluid is passed to the system inlet. A baffle can be used to increase the flow circulation and hence improve the air release. It also reduces the fluid move­ment due to motion of the reservoir itself.

Passing the return flow through a diffuser in the reservoir reduces the fluid velocity and, by directing the fluid away from the bottom of the reservoir, reduces the re-entrainment of solid contaminant and water from the bottom of the reser­voir. Transient changes in the fluid level and the release of air require the fitment of a breather. This must contain a filter that is sized to the minimum requirements of the system. It is preferable that the fluid is filtered during topping-up or replenishing.

Figure 1. Hydraulic Reservoir