Hydraulic Reservoir

Hydraulic reservoir is an essential requirement of any hydraulic system as it is the fluid storehouse of the entire system. A hydraulic reservoir is basically a storage tank that is used to store liquids or gases used in hydraulic machines or fluid power applications. All hydraulic systems need a fixed quantity of liquid that is stored and reused as the entire hydraulic circuit works. That is the hydraulic circuit has a small part, which is used as a storage reservoir or tank. This can be installed on the machine itself or can found as a stand alone unit. But in both the cases, the design of the hydraulic fluid reservoir and implementation is very important. Infact, the efficiency of a well-designed hydraulic circuit depends greatly on the reservoir design. A poor tank or reservoir design will hamper the performance of the hydraulic circuit.

Functions of Hydraulic Reservoir Tanks

The hydraulic reservoir or tank is used to a number of functions in the hydraulic system:

• fluid storage
• separation of air
• dissipation of heat
• settling of contaminants

The hydraulic reservoir contains enough fluid to supply the normal, regular operating requirements of the hydraulic system , with an additional supply to replace the liquid lost through minor leaks. Besides this, hydraulic tanks or reservoirs allow the settling any contaminants or impurities and separation of air from the liquid before reuse in the hydraulic system.

Hydraulic Tank Shapes

• Cylindrical
• Rectangular
• T-shaped
• L-shaped

Materials of Construction

• Plastic
• Stainless steel
• Steel
• Aluminum

Installation of Hydraulic Reservoir

The mounted hydraulic reservoir is of better use than a separate stand alone unit. However, to get the maximum usage, the reservoir should be located above the pump so that the inlet of the pump is always flooded. This helps in improving the suction conditions of the pump, reducing the vortex flows and cavitation. The hydraulic tank should also be located in a well-ventilated area as it will improve the heat dissipation.

Hydraulic Fluid Reservoirs Capacity

They are available in a wide capacity range. The point to be noted that the reservoir should be large enough to bear and store the thermal expansion of fluids and changes in fluid level on account of normal system operation.

Features of Industrial Hydraulic Reservoir Tanks

There are wide variety of features available in hydraulic reservoirs.

• Pressurized devices are installed in hydraulic systems in case if there is not sufficient atmospheric pressure to maintain a net positive suction. In such cases, there are hydraulic reservoirs with both air-pressurized and liquid-pressurized devices.
• Some hydraulic reservoirs have relief valve which helps to keep the device at a safe operating pressure. There are hydraulic reservoirs coated with a rust-inhibiting feature.
• Some have a hinged or fully removable top.
• There are hydraulic reservoirs with internal temperature gauges, which is very popular.
• Foam-retarding diffusers are sometimes built into the hydraulic reservoir to prevent foaming or fluid blow-over.

Manufacturers also produce hydraulic reservoirs as per international standards by various organizations like the Joint Industrial Council (JIC), the American Society of Lubrication Engineers (ASLE), the National Fluid Power Association (NFPA), Deutsche Industrie Norm (DIN). The reservoirs in such cases are produced as per the sizing requirements and other technical considerations put forward by these organizations.