it is about basic concepts of pumps, classification and characterization curves
Centrifugal Pumps
Centrifugal Pumps
CENTRIFUGAL PUMPS
Full description
Centrifugal pump is a machine that helps in lifting water or any other liquid from lower level to higher level. Such types of pumps are used for a variety of applications such as waterfalls, founta...
Centrifugal Pumps Learning HVAC
Maker : Pompe Garbarino S.P.A
Comparing Reciprocating Pumps and Centrifugal Pumps
Descripción completa
Gland Packing for Centrifugal PumpsFull description
Rotor Rotor--Dynamic -Dynamic Pumps Rotor--dynamic Rotor -dynamic pumps can be broadly classified into three main types, there are: a) Centrifugal Cen enttrifu rifug gal pumps pum pump ps b) Mixed Mixe Mixed d flow flo flow pumps pump umps c) Axial Axial Axial flow flow pumps pump pumpss (also (als (also o known know known n as as as propeller prop propell eller er pumps)
1
Rotor--Dynamic Pumps Rotor
Rotor--Dynamic Pumps Rotor
2
Positive Displacement vs Centrifugal Positive Displacement
Centrifugal
Takes clearly defined volumes of fluid from the inlet side of the pump, and transfer the fluid to the delivery side
Relies on the hydrodynamic action of impellers, which are mounted onto the motordriven shaft to induce fluid flow from the inlet to the delivery side
Ability to hold pressure
Seals to prevent the fluid returning to the inlet side when the pump is stopped
Has no ability to sustain pressure when at rest; the inductive action relies entirely on the impeller motion
Ability to generate pressure
High pressure is generated by displacing the liquid against the resistance on the delivery side.
Limited pressure on the delivery side when kinetic energy is converted to pressure by the volute.
Enters axially from one side of impeller and flow radially outwards
Enters axially from both sides of impeller and flow radially outwards
Enter axially and flow axially outwards
Comparative capacity (flow rate)
Lower
Medium
Higher
Physical size
Propeller pumps can be very large
Comparative Higher (up to 16 pressure (flow rate) bars)
Medium
Lower
Number of impellers
Shaft could only fit one impeller
Shaft could only fit one impeller
Can be connected in series to increase pressure
5
Centrifugal Pump - Description Main parts: -
Impeller
-
Shaft
-
Impeller journal
-
Wear ring
-
Casing
-
Bearing Bush
-
Packing / Mechanical seal
-
Coupling spacer
-
Shaft coupling
Spaced coupled vs Closed coupled
6
Centrifugal Pumps ►
Design of centrifugal pumps can vary widely in details
►
Most have the characteristic volute shape of casing, necessary for efficient collection of the outflow from the impeller, converting the kinetic energy into pressure energy.
Mixed--flow Pump Mixed Main parts: - Impeller - Shaft - Impeller journal - Wear ring - Casing - Bearing Bush - Packing / Mechanical seal - Coupling spacer - Shaft coupling
7
Multi--Stage Centrifugal Pump Multi Main parts: -
Impeller
-
Shaft
-
Impeller journal
-
Wear ring
-
Casing
-
Packing / Mechanical seal
Multi--Stage Centrifugal Pump Multi Series of centrifugal pumps arranged to supply one another in series and thus progressively increase the discharge pressure. pressure. Applications: -DeepDeep-well cargo pumping (vertical), driven by electric motors or hydraulic motors outside the tanks - Boiler feed pump (horizontal)
8
Air--Priming Air ►
Centrifugal pumps are not selfself -priming
►
Require some means of removing air from the suction pipeline and filling it with liquid.
►
Purposes:
To avoid running the pump dry that could damage the sealing surfaces between journal and wearwear-rings To enable pumping (taking suction and deliver t he fluid) as soon as the pump is run
Air--Priming Air ►
Where the liquid to be pumped is at level higher than the pump,
►
Open an air cock near the pump suction will enable the air to be forced out as the pipeline fills up under the action of gravity.
If the pump is below sea water level, and sea water priming is permissible in the system,
Open a sea water injection valve and the air cock on the pump will effect priming.
9
Air--Priming Air ►
Air priming unit can be provided to individual pumps.
Air--Priming – Air – Methods (General)
Manual Filling
10
Air--Priming – Air – Methods (General)
Air--Priming – Air – Methods (General)
11
Air--Priming – Air – Methods (General)
Air--Priming Air ►
Central priming system may be connected to several pumping systems.
12
Axial--Flow Pumps Axial ►
Axial-flow (and semi Axialsemi--axialaxial-flow) pumps are frequently used for large volumes (capacity) and low heads (pressure).
►
They are simple and occupy little space.
►
It is an equivalent to a low low lift lift centrifugal pump.
Axial--Flow Pumps Axial ►
►
An axialaxial -flow pump uses a screw propeller to accelerate the liquid. The outlet passages and guide vanes are arranged to convert the velocity increase of the liquid into a pressure.
13
Axial--Flow Pumps Axial
Axial--Flow Pumps Axial ►
An axialaxial -flow pump uses a screw propeller to accelerate the liquid.
►
The outlet passages and guide vanes are arranged to convert the velocity increase of the liquid into a pressure.
►
They are reversible in flow direction provided that they are driven by a reversible primerprimer -mover.
14
Axial--Flow Pumps Axial ►
Pump casing is split either horizontally or vertically to provide access to the propeller.
►
A stuffstuff -box prevents leakage where the shaft leaves the casing.
►
A thrust bearing of tilting pad type is fitted on the drive shaft.
Axial--Flow Pumps Axial ►
The axialaxial-flow pump is used where large quantity of water at a low head is required.
►
In Steam Turbine ships, they are often used in condenser circulating or as a supplementary pump in condenser scoop circulating (since the pump offers little resistance to flow when idling).
►
With scoop circulation, the normal movement of the ship will draw in water; the pump would be in use only when the ship is moving slowly or stopped.