Lecture 9: Pumps (All Parts) Flashcards
(35 cards)
What is a positive displacement pump?
A positive displacement pump traps a fixed amount of fluid and forces it into a discharge pipe.
What are the two main categories of pumps?
Dynamic pumps and positive displacement pumps.
What is the difference between a centrifugal pump and a positive displacement pump?
Centrifugal pumps use kinetic energy, while positive displacement pumps use mechanical energy.
What are some common types of positive displacement pumps?
Reciprocating pumps, rotary pumps, and diaphragm pumps.
What is the difference between a reciprocating pump and a rotary pump?
Reciprocating pumps use a piston or plunger, while rotary pumps use a rotating mechanism.
What is the difference between a gear pump and a vane pump?
Gear pumps use interlocking gears, while vane pumps use sliding vanes.
What is the difference between a positive displacement pump and a positive displacement compressor?
Pumps move fluid, compressors move gas.
What is pump performance and how is it measured?
Pump performance is the ability to move fluid at a certain rate and pressure, measured by flow rate, head, power, and efficiency.
What is the difference between head and pressure in a pump system?
Head is the height a pump can lift fluid; pressure is the force a pump can exert on fluid.
What is the difference between a single-stage pump and a multi-stage pump?
Single-stage has one impeller, multi-stage has multiple, for higher head.
What is cavitation and how does it affect pump performance?
Cavitation is vapor bubble formation due to low pressure, which can damage pumps and reduce performance.
What is the difference between NPSHr and NPSHa in a pump system?
NPSHr is the minimum suction head to avoid cavitation, NPSHa is available head in the system.
What is the difference between a fixed displacement pump and a variable displacement pump?
Fixed delivers a fixed amount per cycle, variable adjusts output based on demand.
What is the difference between a diaphragm pump and a piston pump?
Diaphragm pump uses a flexible diaphragm, piston pump uses a rigid piston.
What is the difference between a positive displacement pump and a centrifugal pump in terms of flow rate and pressure?
Positive displacement pumps provide constant flow; centrifugal pumps vary flow with pressure.
What is the difference between a single-suction pump and a double-suction pump?
Single-suction has one inlet, double-suction has two for high flow rates.
What is the difference between a lobe pump and a screw pump?
Lobe pump uses interlocking lobes, screw pump uses a helical screw.
What is the difference between a positive displacement pump and a dynamic pump in terms of efficiency?
Positive displacement pumps are more efficient at low flow rates and high pressures; dynamic pumps are more efficient at high flow rates and low pressures.
What is the difference between a volute pump and a diffuser pump?
Volute pump has a spiral casing; diffuser pump has stationary vanes.
What is the difference between a canned motor pump and a magnetic drive pump?
Canned motor pump integrates motor and impeller; magnetic drive uses magnetic coupling.
What is the difference between a self-priming pump and a non-self-priming pump?
Self-priming can evacuate air and prime itself; non-self-priming needs a flooded suction line or external priming.
What is the difference between a horizontal pump and a vertical pump?
Horizontal has a horizontal shaft on a baseplate; vertical has a vertical shaft on a pedestal or sump.
What is the difference between a close-coupled pump and a frame-mounted pump?
Close-coupled has motor and impeller on a common shaft; frame-mounted has them on separate shafts with a coupling.
What is the difference between a single-phase motor and a three-phase motor?
Single-phase has one power phase for low power; three-phase has three phases for high power.