Regarding the following seals, what hydraulic fluid is compatible with each? A) Butyl Rubber B) Neoprene and Buna-N
Skydrol and Petroleum
Where are filters installed in the hydraulic system?
Return line
What is an open center system? What is the fluid doing when system is idle?
an open center system is one having fluid flow, but no pressure in the system when the actuating mechanisms are idle
What regulates system pressure when a constant speed pump is in use?
Pressure Regulator
Gradual pressure build up is the advantage of which system?
Open Center System
How and why are non-pressurized reservoirs kept under a slight pressure?
are slightly pressurized slightly by thermal expansion and the return of fluid to the reservoir from the main system. This pressure ensures that there is a positive flow of fluids to the inlet ports of the pump
What supplies pressure to pressurized hydraulic reservoirs?
Bleed Air or Hydraulic Pump pressure
What items are needed in a reservoir module?
Filters, Check Valves, Test Port, Manual Bleed Valve, and Gauge Port
What elements make up an inline filter assembly?
Head Assembly, Bowls, Element
How do you keep hydraulic fluid from being contaminated while servicing and what is the most effective way?
Quick Disconnects and the use of a Hydraulic Filler Unit
Which type of filters is meant to be thrown away?
Micron Type Filter
How is a check valve identified?
Directional markings on outside of check valve.
Why would you use a hydraulic fuse?
to prevent loss of fluid, it detects a sudden increase in flow and shuts off the flow.
What problems would exist if you used a relief valve as a pressure regulator in a large hydraulic system?
Pump is constantly under load and the energy expanded in holding the valve off its seat causes heat build up.
Which valve is used to lower the systems pressure to a specific amount?
Pressure Reducer
What are the functions of an accumulator?
Dampen pressure surges, Store power, Aid or Supplement power pump, and Supply fluid of small internal leaks.
Which valve would be used to enable one unit to automatically set another unit in motion?
Sequence Valve
Can a power driven pump be mechanically actuated? yes or no
Yes, by a hand pump
Explain what the working mechanism is for a Gear Pump.
two meshed gears revolve in a housing
Explain what the working mechanism is for a Gerotor Pump.
internal gear rotor (7 wide teeth) and a spur driving gear (6 narrow teeth)
Explain what the working mechanism is for a Piston Pump.
Pumping Pistons
Explain what the working mechanism is for a Vane Pump.
four vanes (blades), a hollow steel rotor with slots for the vanes, and a coupling to turn the rotor.
How is displacement determined with a piston pump?
Size of Piston, Length of stroke, Number of Pistons.
On a variable displacement pump, what is the purpose of the pump compensator?
The pump output is changed automatically by a pump compensator.
Which valve switches fluid flow through an actuator?
Selector Valve, Direction Control Valve
Which valve allows a restricted flowing the opposite direction when closed and how does it work?
Orifice Check Valve, has a small calivrated orifice machined into it to let fluid flow back
Which valve only lets fluid flow in one direction and how is that direction identified?
Check Valve, an arrow on the outside of the housing.