Compressors Flashcards
A double acting piston is connected directly to the connecting rod? True or false?
False it is connected to the CrossHead
The purpose of a crosshead is to keep the………… Centred in the packing throughout the full stroke
Piston rod
What causes reciprocating compressor valves to open?
The pressure differential
Intercoolers are used on double…………. Compresses to cool the air
Stage
List the three components that the Alberta boilers safety association requires to be installed on every air receiver?
Safety relief valve
Pressure gage
Drain
If there is any possibility of a blockage in a compressed air system what must be installed on the pressure side
The safety relief valve
Compressor capacity is usually determined by the amount of gas that enters the suction inlet in a given period of time?
True or false?
True
A two-stage compressor must compress the gas on both sides of the piston?
True or false
False it can be single acting
Double acting compresses compress the gas on both sides of the piston? True or false?
True
0° Kelvin is equal to 273°C?
True or false
True
Atmospheric pressure at sea level is equal to how many of each of the following?
Bar?
Psi?
Kpa?
Bar=1
Psi=14.7
kPa=101.4
You calculate gauge pressured by adding 14.7 to an absolute scale reading?
True or false
False, You subtract 14.7psi
Compressed air operates in much the same manner as well in a hydraulic system except for two major differences, what are these two differences?
Gases are compressible
Gases expand to fill any container
List the three ways air pressure can be increased?
Heat it
Reduce the volume
Add more gas into a confined space
Define pascal’s law
Pressure in a confined static fluid acts equally and in all directions at right angle of 90°
When pressure is increased in an enclosed space, The Temperature:
Increases
If the flow rate is Constant and the velocity is decreased, there will be a………. In pressure.
Increase
With an increase in altitude, hey compressor needs………….. Power to drive the compressor.
Less
The combined gas law demonstrates the relationship between three variables before and after compression. State the formula that shows the relationship.
P1xV1/T1=P2xV2/T2
Which compressor has the power pistons and the compression pistons sharing the same crankshaft?
The integral
List the two reciprocating compressors are particularly suited to oil free delivery.
Labyrinth and diaphram
Positive displacement compresses work on the principle of trapping a specific volume of air and then reducing that volume to get a higher pressure? True or false?
True
How do you compresses move gases work?
They raise the gas pressure
What is displacement?
Displacement is the total volume of air actually moved out of the compression cylinder in a given unit of time.
What is pressure ratio
Pressure ratio is a ratio of the absolute discharge pressure compared to the absolute intake pressure.
What is Volumetric efficiency?
Volumetric efficiency is a ratio of the actual compressor capacity compared to the calculated displacement and is expressed as a percentage
What is swept volume
Swept volume refers to the volume of air that is swept or pushed out of the cylinder on the compression stroke
What is clearance volume?
Clearance volume refers to the space between the piston and the cylinder head when the piston is at top dead center.
Standard cubic foot
Hey standard foot of gas is the amount of gas that fills one cubic foot volume exactly at standard conditions
What is staging
Single stage compression refers to those compresses in which compression from initial to final pressure is completed in one single step or stage.
What is a single acting compressor
Compression occurs on only one side of the piston, or compression occurs on only one stroke for every revolution of the crank shaft.
What is a double acting compressor
Compression stroke occurs on each stroke of the piston (on both sides) or compression occurs on two strokes for every revolution of the crankshaft
What is venting
Before work on a compressed air system the pressure inside must be vented.
What is a clearance pocket
Clearance pocket increases the clearance volume to reduce the compresses efficiency.
What is Rod loading?
Rod loading refers to the sum of the suction and discharge pressures acting on both sides of a double acting compress piston
What is Rod reversal
Rod reversal is a reciprocating compressor term that has to do with the alternate compression and tension forces of the piston rod during operation