Hydraulics- Pumps- Hoses Flashcards
Rotary pumps are what type of displacement?
positive displacement
What is the most common type of rotary pump?
the gear type pump
What are the 5 types of rotary pumps?
Gear, vane, screw, sliding shoe, multiple piston
What may result from improper design, excessive suction lift, improper piping
cavitation
What are the disadvantages of a centrifugal pump?
suction lift and sensitivity to head and speed
What is the best and most modern way to align pumps?
laser optical
Shelf life of hoses
10 years
Flexible hoses must not be twisted during installation because
The service life of the hose would be reduced and fitting may become loose
What happens to flexible hose under pressure?
length contracts and diameter expands
Beta 5 = _____ the removal of what %?
Beta 5=10 removes 90%
Beta 10 = ___ removes what %?
beta 10 = 50 removes 98%
What are the 4 basic types of hydraulic pumps
Vane, piston ,gear, screw
What is the most common liquid contamination of hydraulic fluid?
Water
What are the five flow control valves?
Stop, globe, needle, Gate, plug cocks
at what contamination level will water show cloudiness in hydraulic fluid?
Cloudiness at .03%
What is the max allowable water content in hydraulic oil?
500ppm
What pump is seldom used, simplest of pumps, 600 psi or less?
Gear pump
What pump is rugged and highly efficient, range of 6,000 PSI or more?
Piston
What PUMP IS EFFICIENT AND Small 2,000 psi?
Vane
What pump is used for power transmission in sub 3,00 psi?
Screw
Hydraulic motors are commonly used with what type pumps?
Vane and piston
What is pressure?
The direct result of resistance of fluid flow
What chapter of the M9000 is the flex hose program?
505 flex hose program
Hose slack in a hydraulic hose should be between?
5-8%
When making a hose tag what should be on the tag?
Replacement date
What is cavitation?
When absolute static pressure drops below the liquid’s vapor pressure
What is done for BECCE’s to prevent damage from a too realistic scenario?
Dry run
What percentage of working pressure do you test a temporary hose to?
200%
Which hose is not part of a hose log?
Outboard hoses
When do you change hydraulic oil?
every 500 hours of operation
What position do vanes get stuck in?
Retracted position
What are the 4 positions of a DCV?
Open, Closed, Floating, tandem
When grit or debris is caught in a vane pump what happens?
Vane is stuck in retracted position
The difference between inlet and outlet pressure at full flow (rated capacity)?
Full flow differential pressure(set pressure)
Cavitation in piston pump on initial startup?
Restricted inlet to the pump
Hydraulic strainers are located where?
Before pumps or at the reservoir fills
Hydraulic filters are located where?
after the pump, return line, before entering the reservoir, and bypass loop
What is the most desirable flow in a hydraulic system?
Laminar flow
What is the least desirable flow in a hydraulic system?
Turbulent flow
How often do you check viscosity in hydraulic oil?
Systems used daily-check semi annually or
any less check annually
What is the greatest effect on viscosity in hydraulic oil?
Heat
Selecting the correct hydraulic connector or fitting depends on what?
Fluid mediation
A fitting in a hydraulic hose can be connected in which ways?
Crimped or swaged
What is the preferred viscosity index for most hydraulic systems?
90 above