Compressor

Question 1

What are the 2 types of compressors?

Answer 1

Positive displacement

Dynamic

Question 2

What are the 2 types of reciprocating compressors?

Answer 2

Piston and diaphragm

Question 3

What are the 2 types of rotary compressors?

Answer 3

Sliding vane

Screw

Question 4

What are the 2 types of dynamic compressors?

Answer 4

Centrifugal and axial

Question 5

How does a reciprocating compressor work?

Answer 5

1. Volume increases in the cylinder
2. This pressure difference causes a valve to open
3. Air enters the cylinder while closing the outlet valve
4. As the piston is forced up, the volume of air in the cylinder is reduced -compression
5. inlet closes and outlet opens allowing compressed air to be released

Question 6

How does a simple spring valve work?

Answer 6

It’s a non return valve and the pressure acts on a spring which allows it to open and air to enter

Question 7

How does a Reed valve work?

Answer 7

It’s a one direction/ non return valve which opens and closes due to changing pressure across both sides

Question 8

How does a double acting compressor work?

Answer 8

Produce a more even supply of air than a single, uses two sets of valves

Question 9

What is a cross head?

Answer 9

Keeps the piston rod perpendicular

Question 10

What are the advantages of a multi stage compressor?

Answer 10

Efficiency
Less heat
Less wear on parts

Question 11

How does a diaphragm compressor work?

Answer 11

Piston is separated from the suction chamber but still moves in a reciprocating motion

This prevents the air becoming contaminated with oil and other dirt

Question 12

Why is oil injected into the rotary vane compressor?

Answer 12

Cool the air
Lubricate the air
Provide a seal between the vanes and stator walls

Question 13

How does the rotary vane compressor work?

Answer 13

Air is drawn in from the atmosphere and trapped between the rotating vanes

Vanes are then pushed in and the volume reduces increasing the pressure

Highest pressure of air is released to the compressor outlet

Question 14

How does a screw compressor operate?

Answer 14

As rotary revolve, air is drawn into the large volumes which is then forced through rotors where the volume gets smaller and the air is compressed

Question 15

What is the screw compressor available in?

Answer 15

Oil flooded or dry versions

Question 16

What is the purpose of an oil bridges in a rotor?

Answer 16

Provide a seal and assist in transferring mechanical energy

Question 17

How does a dynamic compressor work?

Answer 17

Air is drawn into the compressor abs takes place due to acceleration, pressure is increased by kinetic energy

Question 18

How does a centrifugal compressor work?

Answer 18

Air is trapped between blades and is then accelerated, this throws air outwards leaving the blade tips with increased Velocity and pressure

Then enters a diffuser and collecter where air becomes a higher pressure

Question 19

How does an axial compressor work?

Answer 19

Utilises centrifugal force to compress atmospheric air which is moved axially , compression takes place as volume gets smaller