403 - Pumps Flashcards
Two types of pumps
Positive displacement pumps
Non-Positive displacement pumps
Types of positive displacement pumps
Reciprocating pumps
Rotary pumps
Types of reciprocating pumps
Piston pumps
Plunger pumps
Diaphragm pumps
Types of rotary pumps
Progressive cavity Sliding vane Lobe Gear Peristaltic Screw
Progressing cavity
Rolls liquid Very thick liquid 3 stages of rotor and cavity Solid size smaller than opening Takes up a large amount of space and is expensive Very gentle pumps
Progressive cavity advantages:
Self-priming/Suction lift Ability to vary capacity Non-pulsating flow Generates high pressure due to staging Abrasive fluids Handles high viscosity
Progressive cavity disadvantages:
Can’t run dry
Length of pump
Large foot print
Sliding vane pump
Unbalanced design
Allows for reverse flow, but need to reverse the check valve
Seals very well
Sliding vane pump advantages
Self-priming/Suction lift
Ability to vary capacity
Run dry for a short time
Handles low viscosities
Sliding vane pump disadvantages
Abrasive solids damage pump
Medium pressure capabilities
Material limitations
Not suitable for high viscosities
Lobe or Cam pump
Lobes don’t transfer power by touching each other, gears on the outside do that.
Lobe pump advantages
Self-priming/Suction lift
Ability to vary capacities
Reversible
Handles high viscosities
Lobe pump disadvantages
Abrasive resistance Pressure capabilities Stuffing box Jamming Pump efficiency Non-pulsating flow
External gear pump
Also known as trash pump
Becoming less common
External gear pump advantages
Self-priming/Suction lift High speed Ability to vary capacity Non-pulsating pump (depends on the speed) Run dry for a short time High temperature
External gear pump disadvantages
High pressure causes slip No solids allowed Abrasion High shear Low viscosity fluids
Internal gear pump
Very common
Similar to external gear pumps
Internal gear pump advantages
Ideal for high viscosity liquids
Constant non-pulsating flow
Self-priming/Suction lift
Low NPSH required
Internal gear pump disadvantages
High pressure causes slip No solids Not abrasive resistant High shear, metal to metal contact Low viscosity fluids
Screw pump
Not as common
Screws don’t touch
Very fast and very high volume
Screw pump advantages
Non-contacting
Non-pulsating flow
Run dry for a short time
High flow and high pressure
Screw pump disadvantages
Solids
Abrasions
High shear
Low viscosities fluids
Peristaltic pump
Pulse type
Medical industry
Peristaltic pump advantages
Self-priming/Suction lift Ability to vary capacity Handles "difficult" fluid Reversible Can run dry No seals
Peristaltic pump disadvantages
Pressure Temperature Short hose life Pulsation High HP requirement Less efficient
Air diaphragm pump
Valve goes back and forth due to differential pressure.
Real simple
Air diaphragm pump advantages
Self-priming/Suction lift Ability to vary capacity Handles abrasive and suspended solids Handles viscous liquids Run dry Length of pump No seals Submersible No efficiency loss due to air
Air diaphragm pump disadvantages
Pressure Noise Pulsation Limited by air flow and compressor Power consumption
Types of Non-Positive displacement pumps
Centrifugal pump
Volute pump
Diffuser pump
Concentric volute pump
Centrifugal pump
Pressure creating device
Converts velocity energy to pressure energy
Flow depends upon system characteristics
Volute pump designs:
Radial design
Mixed flow
Axial flow
Diffuser pump designs
Vertical turbine
Horizontal
Concentric volute designs
Regenerated turbine
High speed
Radial vane
Recessed impeller
Part A
Negative pressure inside the pumps pushes the fluid to the inside is the pump.
Part B
The impellers coverts velocity energy to pressure energy.
Part C
The fluid is at a maximum pressure energy.
Part D
The fluid leaves the impellers after reaching a max pressure energy.
Part E
The fluid is being discharged from the pump.
