Compressors Flashcards by Zach Hamm

What is the biggest concern with compressors?

Moisture

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What is the most important thing on a Compressor / pneumatic system?

Volume of air

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How are compressors classified??

Principle operations
Their motion

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What is maximum pressure control.?

It prevents further compression one the required maximum is reached

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What is an unloading device?

’ It consist of a set of fingers controlled by a pilot line from the systems air pressure

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What are other methods to controlling the maximum air pressure of the Compressor?

Throttling the air intake
Using an variable speed drive
Using an pressure switch

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Where would axial compressors be used?

Gas turbines

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What are some benefits of an axial compressor?

High efficiency
Large Mass of flow capacity

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What are 2 disadvantages of axial compressors?

Large pressure rising make them complex
Expensive

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What is the purpose of a diahgram in a compressor ?

Prevent short cycling of air
Stop air from leaking from one side to the other

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What are a few things lubricants must have (4)?

Excellent protection from rust and corrosion
Good demulsibility to shed water that enters the lube system
Prevention of acidity, sludge, deposit formation
Good foam control

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What does BDC stand for?

Bottom dead centre

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What style of piston rings ave found in both single-acting and double acting compressors?

Compressor rings

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What are the three measurements that must be made on an overhauled channel value?

End clearance
Side clearance
Lift

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What value is best suited for high speed services?
A. Feather
B. Channel value
C. Dampenend disc value
D. Concentric Ring value

C. Dampenend disc valve

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Why is it a mistake to clean the value before inspecting it?

Because you can erase valuable clues such as leaks, and foreign parts

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Why should you rotate the compressor at least once prior to starting up?

Ensuring nothing is hitting, binding or rubbing

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A pressure differential causes this component to open/ close?

Valves

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What is the primary function of the distance piece?

Prevent contamination between the cylinder gases and the oil from the crankcase

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What Motion does a crankshaft convert of the prime mover? What then does a prime mover convent to?

Rotary
Reciprocating

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Where are intercoolers located?

Between stages

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Where are aftercoolers located?

After final stage of compression

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When are reciprocating compressors used?

When High Compression ratios are required per stage with high flow rates and where process fluid is relatively dry

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What are the two classifications of industrial compresses

Intermittent (Pd)
continuous flow( c )

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What is a stator?

Comprised of a series of blades attacked to the casing walls

What is the purpose of a shroud?

Provide support for the longer stator vanes at the inlet to provide a gas seal between the rotating and stationary.

What does VVCP stand for?

Variable volume clearance pocket

When measuring a cylinder bore to check for wear , it is important to measure in the area of?

Ring travel

Compared to a dry liner, a wet liner would have thicker or thinner wall thickness?

Thicker

What is the function of Rod packing?

To prevent leakage from the cylinder along the piston Rod.

What type of cut does a pressure breaker have?

Radial cut

The Dots on piston rings, do they go up or down? (Block test)

They go up

How could you make an Compressor more efficient?

Preheating air

Why is a jog or bump test performed on a compressor?

To check rotation

What will happen is a servo value is stuck in the closed position?

The unloader value never gets an oil signal to tell it to close so the Compressor is always trying to supply the full volume of air

How is the operation of the control system set at any specific pressure?

Spring setting on the servo valve

What component contains the inlet/outlet ports in a wet sliding vane compressor?

Stator

Where is the servo valve located in a sliding vane compressor?

Oil reservoir

Where is the unloader valve located?

After inlet hose but before the rotor

Which valve May be used to unload the compressor for ease of starting?

Safety relief valve

What does it mean for a compressor to have a built -in pressure ratio?

That its not adjustable

What is the only major moving part in a sliding vane compressor?

Rotor assembly

What are the two main categories of screw compressors

Wet screw Dry screw

Which rotor is the driver on a screw compressed

Male rotor

What 4 things determine the capacity of a screw compressor?

Rotor length Diameter Lobe (flute) design Speed

What determines the discharge pressure of a screw compressor?

Length of the compression path along the lobes and flutes but for most part determine by the location of the inlet and/or discharge ports

Which component does the air enter after leaving the oil-flooded Compressor?

Separator

Which valve operates like the thermostat in a motor vehicle ?

Thermal mixing valve

What is a screw compressors simplest type of control system?

Online/offline

What does VFD stand for?

Variable frequency drive

When being proper maintained , how many hours in between majoroverhauls can the Compressor experience?

80,000 to 100,000 hrs

What could result in a compressor when there is a stuck blowdown valve?

Low air delivery

What is the most common cause of high discharge air temperature in a liquid cooled compressor?

A restriction of flow of the cooling air through the radiator

What is pressure ratio (PR)?

Is the ratio of the absolute Compressor incoming air pressure to the absolute compressor discharge pressure.

What does A pressure valve do?

Keeps air from back flowing Males sure all systems are running before adding pressure

At what pressure with the valve stay open? (Sliding vane compressor)?

60Psi

What does aux mean?

Nice to have

What does Ann mean?

Must have

What do oil return valves do?

Prevents hydraulic locking Prevent pump from being over pressurized

What is another name for vacuum pump ?

Negative pressure (below 14.7)

What does A vacuum relief valve do?

Prevent a vacuum buildup within the rotor area and to prevent the vanes to become unstable and chatter or bounce around

How do lobe/roots blowers move air?

One moved an fixed volume of air from one side of the blower to the other as the lobes rotate

When are timing gears used?

Dry applications

Why use three lobe blowers? (4)

Increase efficient Less slip Less noise less leakage

What is an unloading device?

Allows the drive to run with the least hp demand when it reaches maximum fair pressure

What does adiabatic mean?

An process or condition where Heat dosent leave or enter a system

What does ISOthermal mean?

Involving or containing a constant temperature

What is the purpose of an diagram in a compressor?

Prevent short cycling Stop air from leaking from one side to the other