Theory 1 Flashcards
What is the definition of a system?
A system is a series of interconnecting pipes and components that will deliver a substance from one point to another.
What are the two types of systems?
- Open loop
- Closed loop
What is an open loop?
The working fluid is consumed e.g. Fuel, domestic fresh water
What is a closed loop?
The working fluid is re-sued e.g. lub oil system, fresh water cooling system
Name 3 types of tanks? And what their purpose is?
- Header Tank- Reservoir to top up a system.
- Service tank- supply of clean, water free fuel.
- Drain tank- collects oil returning from a system.
Name 3 types of tank gauges? And what their purpose is?
- Contents gauge- (clock/dial) How much fluid is in a tank.
- Gauge glass- Visual indication to tank level (press the button to read)
- Sounding tube- Used to measure the depth of liquid in a tank (Dip tape)
What is a Strainer?
Removes large course particles, usually metal plates with holes in or a wire basket.
What are the benefits of a strainer?
Usually washable and re-useable
What dose the type of pipework depend on?
- service being supplied (the fluid)
- operating temperatures and pressures
- other types of material used within the system(what the pipework might fit into)
Name the different types of pipework and the services they do?
- Phosphor bronze- High pressure salt water
- Copper - Domestic Fresh water
- Copper Nickel- Lub Oil
- Brass- Castings (valves, couplings, junctions, taps)
- Plastic- Sewage/waste systems and pre-wet
What dose the type of seal used depend on?
pressure
fluid being used
temperatures involved
Name the types of seals used? And a discription?
- Gaskets – Create a seal between two flat surfaces, can be made from various materials including Non Asbestos Fibre (NAF) – Paper – Leather – Cork – Copper - Rubber
- Mechanical Seals – Used on rotating components such as pump shafts
- Keeler Ring Couplings – Used on High Pressure Air system pipework connections
- Gland packing – Silicone, wool, wax – dependent on fluid type, pressure and temp
What is the purpose of valves?
To provide a method of controlling flow or pressure of a fluid or to provide a means of isolating various systems or components.
Name the different types of valves?
globe valve
gate valve
flap valve
Saunders valve
Ball seated cock
Relief Valve
Reducing Valve
Non-return Valve
Pressure Control valve
ROV (remote operation valve)
What is a relief valve?
Prevents over pressurisation
What is a reducing valve?
Reduces pressure for a part of a system
What is a non-return valve?
Prevents reverse flow
What is a pressure control valve?
Maintains pressure in a system at a set level, monitors the outlet pressure from the vavle.
What is an ROV (remote operation valve)?
Rod gearing to manually open or close a valve from another location or automated
What are the two types of pumps used on ship?
Positive displacement
Dynamic Displacement