Hydraulic components - Reservoir

Videos

The lifeblood of every hydraulic system is hydraulic fluid. This fluid required to drive the hydraulic system is stored in a reservoir/tank. The size of the reservoir will vary depending on the hydraulic system and application used for. Air trapped inside the fluid will cause problems like aeration. So, a reservoir is designed in such a way to remove trapped air and to cool the pressurized hydraulic fluid. Also, extra space is provided in the system to avoid overfilling as a result of oil expansion. A rim at the filler neck of most of the reservoir is the maximum limit for filling. Another method to prevent overfilling include checking the fluid level using a glass or plastic sight gage, a tube, or a dipstick. Vented reservoir and pressurized reservoir are the two categories of the reservoir. The vented reservoir is open to the atmospheric pressure and the air enters and escapes through the vent line of the reservoir. A filter is integrated on the vent line to remove contamination from the atmosphere. Such reservoirs are placed at the highest point of the hydraulic system to provide maximum gravity/force to the flow. High altitude applications like aircraft use pressurized reservoirs to store hydraulic fluids. The fluid will be closed to the atmosphere and pressurized.

Hydraulic reservoirs can be made of:

steel stainless steel aluminium plastic

Hydraulic reservoirs vary in terms of capacity, but need to be large enough to accommodate the thermal expansion of fluids and changes in fluid level due to normal system operation.

A efficient reservoir should have the following properties:

A large surface area to transfer heat from the fluid to the surrounding environment Enough volume to let returning fluid slow down from a high entrance velocity. This lets heavier contaminants settle and entrained air escape A physical barrier (baffle) that separates fluid entering the reservoir from fluid entering the pump suction line Air space above the fluid to accept air that bubbles out of the fluid Access to remove used fluid and contaminants from the system and to add new fluid Space for hot-fluid expansion, gravity drain-back from a system during shutdown, and storage of large volumes needed intermittently during peak periods of an operating cycle, A convenient surface to mount other system components, if practical.