Short Answer:

A fluid reservoir is a storage tank used in hydraulic or lubrication systems to hold the working fluid such as oil. It supplies the required fluid to the pump and also collects the returning fluid from the system. The reservoir helps maintain a constant fluid level and pressure during operation.

In addition to storage, a fluid reservoir also performs functions like heat dissipation, separation of air bubbles, and settling of contaminants. It ensures that the hydraulic or lubrication system works efficiently and smoothly without interruption.

Detailed Explanation:

Fluid Reservoir

A fluid reservoir is an essential component in hydraulic and lubrication systems. It acts as a container that stores the fluid required for the operation of the system. The reservoir not only provides fluid to the pump but also receives the fluid returning from the system after completing its work. The design and capacity of a fluid reservoir depend on the type of system, operating pressure, and total volume of fluid required.

1. Function of Fluid Reservoir:
   The fluid reservoir serves several important purposes that ensure the effective working of hydraulic systems. Some key functions are:

• Fluid storage: The main function of a reservoir is to store sufficient hydraulic fluid to meet the operating needs of the system. It ensures there is enough fluid for continuous circulation.
• Compensation for volume changes: During operation, fluid expands and contracts due to temperature changes. The reservoir compensates for these variations and maintains a steady fluid level.
• Cooling of fluid: When fluid passes through the hydraulic system, it becomes hot due to friction and pressure. The reservoir provides space for the fluid to cool before it is recirculated.
• Removal of air and contaminants: As fluid returns to the reservoir, it allows trapped air bubbles and dirt particles to settle down or escape, improving fluid quality.
• System pressure stability: The reservoir helps maintain a constant supply of fluid to the pump, ensuring smooth operation and preventing cavitation.

2. Construction of Fluid Reservoir:
   A typical fluid reservoir is made of metal, usually steel or aluminum, and is designed to withstand pressure and prevent leakage. The construction includes:

• Main tank: Holds the hydraulic fluid.
• Breather cap: Allows air exchange while preventing dust entry.
• Drain plug: Used to remove fluid during cleaning or maintenance.
• Baffle plates: Installed inside the tank to separate the returning and suction lines, ensuring air bubbles and contaminants settle down before fluid recirculation.
• Level indicator: Shows the fluid level to help in monitoring and refilling.
• Filler opening: Used for adding new fluid.
• Return and suction lines: The return line carries used fluid back to the reservoir, and the suction line carries fresh fluid to the pump.

3. Working of Fluid Reservoir:
   The fluid reservoir works as a central part of the hydraulic circuit. When the system operates, the pump draws fluid from the reservoir through the suction line. This fluid is pressurized and sent to different components such as actuators or cylinders to perform mechanical work.

After completing its task, the fluid returns to the reservoir through the return line. During this process, air bubbles escape to the surface, and solid impurities settle at the bottom. The reservoir also allows the fluid to cool before being reused. The continuous flow of fluid between the system and reservoir ensures stable pressure and efficient performance.

4. Types of Fluid Reservoirs:
   Fluid reservoirs are mainly classified based on their design and usage:

• Open reservoir: Exposed to atmospheric pressure and often used in small systems where low pressure is sufficient.
• Closed reservoir: Completely sealed and operates under pressure. Used in high-pressure hydraulic systems to prevent contamination and air entry.
• Pressurized reservoir: Contains compressed air or gas above the fluid to maintain constant pressure. Commonly used in aircraft and high-performance hydraulic systems.

Each type has its own application depending on system design and performance requirements.

5. Design Considerations for Fluid Reservoir:
   The design of a fluid reservoir must ensure safety, reliability, and ease of maintenance. Important design factors include:

• Capacity: The reservoir should hold 3 to 5 times the volume of fluid flow per minute of the pump.
• Material: It should resist corrosion and withstand operating temperatures.
• Shape: The shape should promote proper circulation and settling of contaminants.
• Ventilation: Proper breather filters should be used to prevent dirt from entering.
• Accessibility: The reservoir should allow easy inspection, cleaning, and refilling.

Good design prevents overheating, leakage, and contamination, ensuring long system life.

6. Importance of Fluid Reservoir:
   The reservoir plays a vital role in the performance and safety of hydraulic systems.

• It ensures an adequate fluid supply for the pump.
• It helps maintain pressure stability and fluid cleanliness.
• It prevents system overheating by allowing heat dissipation.
• It provides a settling area for air and impurities.
• It reduces the risk of pump damage due to fluid shortage.

Without a proper reservoir, the system would face irregular flow, contamination, and overheating problems, leading to poor efficiency and equipment failure.

Conclusion

A fluid reservoir is more than just a storage tank; it is a key component that supports efficient hydraulic operation. It stores, cools, cleans, and supplies fluid continuously to maintain stable system pressure. Proper design, capacity, and maintenance of the reservoir ensure reliability, prevent damage, and extend the service life of hydraulic and lubrication systems. Thus, the fluid reservoir is essential for the smooth and efficient working of all fluid power systems.