Pneumatics Final Flashcards
What are the two categories of fluid power?
Hydraulics & pneumatics
What are the three things that fluid does?
- It flows
- Takes the shape of its container
- Exerts a pressure
Difference between liquids and gases?
Liquids have a fixed volume and cannot be compressed, gases can be compressed.
Definition of pressure?
Force per unit area
3 ways pressure can be created?
- Force applied
- Column of fluid
- Resistance to flow
Definition of a vacuum?
Any pressure less than atmospheric
Definition of an orfice?
Any restricted passage
The amount of flow through an orfice is determined by 4 thing?
- Size of orfice
- Viscosity of fluid
- Pressure drop
- Temperature
What is Boyles law?
As volume increases, pressure decreases
What slows down the cylinder at the end of its stroke?
Cushion valves
Check valves allow what?
Flow in only one direction
In a multistage compressor which piston is larger?
The 1st stage is always larger than the 2nd stage
What is the benefit of having a multistage compressor?
Builds more pressure.
Pressure is measured in what?
PSI
Flow rate in pneumatics is measured In what?
CFM
You control pressure at what 2 points?
At the compressor and after the receiver tank
What are the 3 types of center conditions?
- Blocked
- Exhaust
- Pressure
Flow controls are in 2 major categories, what are they?
- Fixed
- Adjustable
Give an example of fixed and adjustable flow controls.
Fixed - orfice plate
Adjustable - needle valve
This valve increases exhaust flow in a dcv?
Quick exhaust valve
Air is drawn into a fluid power motor by what?
The smallest volume chamber
To power a double acting cylinder you have to have at least a what?
4 way dcv
Formulas for pressure, force and area?
Force - P x A = F
Pressure - F/A =P
Area - P/F = A
What device cools between multistage compression?
Intercooler
Which device cools after compression?
Aftercooler
Which valve unloads pressure from compressor head when compressor shuts off?
Unloading valve
If unloading valve does not shut off than what is wrong?
Bad check valve
Most common non-positive displacement motor?
Centrifugal
Limiting flow in a fluid power system means you limit what?
Speed
Limiting pressure in a fluid power system means you limit?
Force
3 things that a valve controls?
- System pressure
- Direction of flow
- Rate of flow
Adjustable valve that only deals with down stream pressure is what?
Regulator
Non-adjustable valve that only deals with upstream pressure?
Safety relief valve
What do cushion valves protect against?
Shock and hammer
What are 3 types of contamination?
- Built in
- Generated
- Ingested
What does FRL stand for?
Filter, regulator, lubricator
Why do we use lubrication?
To lubricate seals, reduce friction and heat and to extend the life of something
What are good work practices?
Put parts on rags on their sides, wrap zip ties around hoses to be able to identify where they go.
What do you always have to have after an aftercooler?
Moisture separator
How should you always meter flow to a cylinder?
When in doubt meter out
Definition of a valve?
Consists of a body and a moving part which connects and disconnects within the body
Best place for a flow control?
At or close to the cylinder
