[Air Systems and Controls] Flashcards
Compressors may be either single-acting (compression on one stroke per revolution) or double-acting (compression on both strokes per revolution) NOTE: This means that compression is taking place on both sides of the piston and that each end of the cylinder is fitted with suction and discharge valves.
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What is high pressure PSI?
1,000 PSI to 5,000 PSI
What air distribution system is used for different purposes such as TLI systems and air hose connections?
Nonvital air
Which type of control system regulates the pressure in the air receiver by controlling the output of the compressor without stopping or changing the speed of the unit?
Constant-speed control
What are the two types of valves commonly used in high-pressure air compressors
1) Strip or feather valve
2) Disk-type valve
Describe the W-type low-pressure reciprocating air compressor
3-cylinder and 2-stage (2 first-stage and 1 second-stage)
What does the compressing element of a reciprocating air compressor consist of?
1) Cylinder
2) Piston
3) Air valves
What type of driving unit connection is it when flexible couplings are used to join the driving unit to the compressor when the speed of the compressor and the speed of the driving unit are the same?
Direct-couple drive
What are installed on air compressors for the removal of all but the friction loads on the compressors?
Unloading systems
What is low pressure PSI?
150 PSI or less
What keeps the compressed air from forcing oil back into a lubricator?
Check valve
What type of bottoms do vertically-mounted receivers have and why?
Convex, to permit proper draining of accumulated moisture, oil, and foreign matter
How are compressors classified?
1) Capacity (high or low) of compressing element
2) Source or driving power
3) Method by which the driving unit is connected to the compressor (belt-driven, direct-connected)
4) Whether air delivered is oil-free or non-oil-free
What is the heart of any compressed air system?
Air compressor
How are most medium-pressure and high-pressure compressors cooled?
By the ship’s auxiliary freshwater supply or by seawater pulled from the ship’s fire main or machinery cooling water service mains
What are air receivers called in high-pressure air systems? What are multiple connected ones called?
Air flasks
Air banks
What are the classifications of air compressors?
1) Duplex
2) Single-stage
3) Multi-stage
4) Horizontal
5) Angle
6) Vertical
What is the reservoir of oil that the oil pump draws from?
Oil sump
What are the characteristics of a high-pressure reciprocating compressor?
1) Motor-driven
2) Liquid-cooled
3) 3- to 6-stage (most are 4)
4) Single-acting
5) Vertical