HP Air Flashcards
HP air is divided into Which categories?
- HP Air = 276 bar
- Reduced HP = below 276 bar depending on the equipment
HP Air is divided into which areas?
- IMS ( inside machinery spaces)
2.OMS (Outside machinery spaces)
Services supplied with HP air
- Diesel generator starting
- GT starting
- Ship siren
- Breathing apparatus charging
- Weapons systems
- Hydraulic system accumulator charging
- Air driven machinery operation
- Cross-connection with LP Air system
Hamworthy compressor
- Air is compressed in 4 stages up to 300 bar, with intercooling after each stage
- Automatic plate type valves create a smooth airflow through each cylinder.
- Driven by an induction motor
HP System components
RINGMAIN
- A continuous loop of piping to which air is supplied,and from where services are connected
- Generally divided into 2 sections which can be isolated or connected together
HP Components
Isolating Valve
Allows sections of the ringmain and supply to services to be isolated when not in use,to allow maintenence or damage control
HP Components
Storage Bottles
- Reservoirs of pressurised air without the need for continuous operation of the compressors
HP Components
Reducing stations
- A big block of valves
- Reduces the 276 bar of pressure to a pressure required for specific services
HP Air components
HP & LP Cross-Connection
Emergency backup to the LP air system
HP Air compresser functions
Air inlet
- Takes air from an air treatment plant,to ensure clean air
- Filtered through a filter/silencer to remove fine particles
HP Air compresser functions
4 Compression stages
- Air enters first stage via a suction & discharge plate
- After each stage of compression air goes through a cooler & air pressure relief valve, set to 10% normal stage pressure
- All compression stages are indentical
HP Air compresser functions
Intercoolers
- Coolers fitted after every stage of compression to remove heat
- Also help remove oil & water from air by condensing the vapour passing through.
- Moisture drained every 30mins
- Water jacket safety valves prevent over pressurisation
HP Air compresser functions
Drains & Seperator columns
- All reciprocating compressors are fitted with drains after each stage of compression
- Seperator columns remove moisture from air, they are bottles and as air changes direction water falls to the bottom. drained by a valve every 30 min
HP Air compresser functions
Stage relief valve
Fitted to all 4 stages of the HPAC to prevent damage to system from overpressurisation
How does air compression work?
an air compressor forces more and more air into a space, increasing the pressure.compressed air provides kinetic energy
