H ydraulic C omponents

1. Hydraulic Components Advanced Hydraulics Don Gilliland

2. Hydraulic Components • Reservoirs • Accumulators • Pumps • Valves • Actuators • Conductors

3. Hydraulic Components • Reservoir Functions • Fluid Cooling • Contaminates to settle • Air to escape • Volumetric variance during Actuator operation • Heat Expansion

4. Reservoir Considerations • Atmospheric Venting In many fluid power systems, the only force acting on the hydraulic fluid to move fluid to the pump is the force of atmospheric air pressure. The vent in most fluid power reservoirs is thus critical. The fluid cannot flow out if the air cannot flow in. It is through the reservoir vent that atmospheric air pressure is applied on the hydraulic fluid. • Volumetric variance during Actuator operation Single and two way single rod cylinders both require different fluid volumes during system operation. The reservoir volume must allow for this variance.

5. Reservoir Considerations • Volumetric variance during 1 way Actuator operation • During advancing a controlled distance to the right • More fluid volume into cylinder from reservoir • Air only is forced out through a breather (Reservoir must lower) breather

6. Reservoir Considerations • Volumetric variance during 1 – way Actuator operation • During retracting to the left under load down force • More volume out back to reservoir • Air must go in breather (Reservoir level Raises) breather

7. Reservoir Considerations • Volumetric variance during 1 – way Actuator operation • Breather must have filtration • Keeps contaminates out of cylinder chamber and away from piston seals • Reservoir level change can be quite large breather

8. Reservoir Considerations • Volumetric variance during 2 way Actuator operation • During advancing a controlled distance to the right • More volume in than volume out • Due to Rod volume on right side

9. Reservoir Considerations • Volumetric variance during 2 way Actuator operation • During retracting same controlled distance to the left • More volume out than in • Due to Rod volume on right side

10. Reservoir Considerations • Fluid Cooling Heat is generated in hydraulic fluid from component motion and friction and when pressure forces molecules of fluid together. These molecules begin to rub on components and one another, generating friction and heat. The reservoir should be made of a heat dissipating material and be large enough to allow some motion slowing time to allow heat dissipation. • Contaminate Settling The reservoir should be large enough to allow some motion slowing time to allow contaminate settling during the fluid cooling process.

11. Reservoir Considerations • Fluid Cooling 

12. Reservoir Considerations • Contaminate Settling

13. Reservoir Considerations • Fill cap may be filtered breather and need periodic cleaning

14. Reservoir Leaks

15. Reservoir Leaks • A leaky or overrunning reservoir can spill hydraulic fluid. • The mess • DOT or EPA ramifications • Hydraulic fluid may be caustic with other vehicle system materials • Tires, brake linings, drive belts, wiring, insulation, and even Wheels or Battery Cases can be damaged by some hydraulic fluids.

16. Hydraulic Components • Reservoirs • Review • Next Accumulators • THE END