Basic Systems Flashcards
What are systems?
A series of interconnecting pipes and components that will deliver a substance from one point to another
What is an open loop system?
The working fluid is consumed e.g. fuel, domestic fresh water
What is a closed loop system?
The working fluid is reused e.g. lub oil system, fresh water cooling system
What are the three types of tank?
Header tank, service tank, drain tank
What is a header tank for?
Reservoir to top up a system
What is a service tank for?
Supply of clean, water-free fuel
What is a drain tank for?
Collects oil returning from a system
What are the three types of gauge?
Contents gauge, gauge glass, sounding tube
What is a contents gauge for?
A clock/dial for how much fluid is in a tank
What is a gauge glass for?
Visual indication for tank level (press button to read)
What is a sounding tube for?
Used to measure the depth of liquid in a tank (dip tape and conversion chart)
What are strainers?
Used to remove large course particles, usually metal plates with holes in or a wire basket. Usually washable and re-usable
What does the type of pipework depend on?
Service being supplied (the fluid);
Operating temperature and pressures;
Other types of material used in the system
What are the 5 types of pipe?
Phosphor bronze
Copper
Copper nickel
Brass
Plastic
What are phosphor bronze pipes used for?
High pressure salt water (HPSW)
What are copper pipes used for?
Domestic fresh water
What are copper nickel pipes used for?
Lub oil
What are brass pipes used for?
Castings (valves, couplings, junctions, taps etc.)
What are plastic pipes used for?
Sewage/waste systems and pre-wet
What does the type of seal used depend on?
System pressure;
The fluid being used;
Temperatures involved
What are the 4 types of seal?
Gaskets
Mechanical seals
Keeler ring couplings
Gland packing
What are gaskets?
Used to create a seal between two flat surfaces. Can be made from various materials, including: Non Asbestos Fibre (NAF), paper, leather, cork, copper, rubber
What are mechanical seals used for?
Used on rotating components such as pump shafts
What are keeler ring couplings used for?
Used on high pressure air system pipework connections
What is gland packing?
Made of silicone, wool or wax depending on fluid type, pressure and temperature
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
What are the types of valve
Globe valve
Gate valve
Flap valve
Saunders valve
Ball seated cock
Relief valve
Reducing valve
Non-return valve
Pressure control valve
Remote operation valve
What are relief valves?
Used to prevent over pressurisation (prevents something bursting or being damaged if pressure gets too high by returning excess pressure back to the tank or before a pump)
What are reducing valves?
Used to reduce pressure for part of a system (rest of system still at higher pressure)
What are non-return valves?
Prevents reverse flow (common types - piston type and flap valve)
What are pressure control valves?
Maintains pressure in a system at a set level, monitors the outlet pressure from the valve (to adjust the valve position as required)
What are remote operation valves (ROV)?
Rod gearing to manually open or close a valve from another location or automated e.g. a solenoid operated valve
What are the two types of pump?
Positive displacement pumps and dynamic displacement pumps
What are positive displacement pumps?
Less flow, increases pressure e.g. gearwheel pump, rotary pump
What are dynamic displacement pumps?
Large flow, low pressure e.g. centrifugal pump and axial pump
What is a motor used for?
Converts electrical energy into mechanical motion to drive a pump
What types of system indicators are used?
Pressure and vacuum gauges - bourdon tube and manometer;
Tachometer;
Thermometer;
Flow meters;
Voltage meters
What are bourdon tubes?
Tube extends as pressure increases, moving a needle round a dial
What is a manometer?
U Tube - pressure increase pushes liquid round the U bend
What is a tachometer?
Measures rotational speed (e.g. speed of a motor or pump)
What are the three types of thermometer?
Fixed brass
Standard pocket
Clock/dial face
What are thermometer pockets?
A plug fitted to systems to screw in a fixed brass thermometer. Filled with oil to aid heat conduction
What are filters?
Used to remove small fine particles. Type used depends on system/fluid
What are the two types of filters?
Metallic - wire wool, steel plates and gauze screens. Reusable, can be washed and refitted when blocked
Absorbent - fabrics, felt, yarn, paper. Not reusable
What are accumulators?
They store potential energy (pressure) which is released as required, also used as pulsation - bladder (bag) type and piston type are the most common
What is Bernoulli’s Principle?
As the speed of a moving fluid increases, the pressure within the fluid decreases. Narrowing pipe: speed increases, pressure decreases. Widening pipe: speed decreases, pressure increases.
