precess tech Flashcards
(17 cards)
whats an example of a linear valve
gate valve, globe valve
whats an example of a 1/4 turn valve
ball valve
what are the differences between ball valve and gate valve
ball valve- rotates a ball with a hole to open/close the flow, 1/4 turn (90 degrees), compact, fast, higher cost, gate valve- moves a gate up and down to start or stop flow. linear, requires more space, slow, lower cost.
what are pros of a gate valve
low pressure drop
durable for infrquent opeartion
good for full flow applications
what are cons of a gate valve
slow to operate
not suitable for throttling
bulkier and taller
what are pros of a ball valve
quick to operate
excellent sealing
compact and low maintanence
what are cons of a ball valve
not suitable for throttling
seats can wear if used partially open
more expensive
how does a steam turbine work
water is heated in a closed vessal- boiler, to produce steam ( around 550 degrees) with pressure as high as 3500 psi.
hot steam is passed through the nozzle.
directs the steam onto turbine blades.
thermal to kinetic to mechanical.
shaft is rotated by the mechanical energy resulting in wokr.
steam is cooled and recycled.
what are the parts of the centrifugal pump
shaft, impeller, volute, wear rings, packing box.
what does the shaft in a centrifugal pump do
most items are mounted on shaft that transmits the power and supports the impellar and other rotating parts. usually stainless steel, has good ersion/ corrosion resistence and is strong
what does the impeller do in a centrifugal pump
is the main rotating part that provides the centrifugal accelerator the liquid. has vanes that push the liquid. transmits energy into the fluid. closer impeller: more efficien, cleans liquids. openn impeller/l suits fluids contains solids. fitted inside the volute cassing
what does the volute do in a centrifugal pump
a curve shaped funel increaaes in cross sectional area as it approaches to the discharge port, as the area increases, volute reduces the velocity of the liquid and increases the pressure. kinetic energy to pressure energy.
what do the wear rings in a centrifugal pump do?
maximise efficiency by reducing leakage, less pump mainatnence, replaceable
what does the packing box do in a centrifugal pump
provides a seal to reduce leaks filled with elxible low friction and non abrasive materials. shaft is protected by sleeve.
how does the shaft convert energy
prime mover energy to mechanical
how does the impeller convert energy
mechanical to fluid kinetic
how does the volute casing convert energy
kinetic to pressure
