For liquid and slurry transportation, a centrifugal pump is the best choice. It is a compatible and simple device. In most occasions, these pumps are well known in the performance, size, feasibility and mobility. For household and industrial purpose, the first selection of pumping device is always a centrifugal pump. For heavy duty and other than fluids like greasy substances it is not preferred.
Small centrifugal pumps are most used devices in utility section of process industries. Its application is widely seen in water and liquids transport in the household and municipalities.
Centrifugal pumps are available in two types:
- Horizontal centrifugal pumps
- The vertical centrifugal pump used for pumping out the groundwater from well and even from the sumps
Centrifugal pump manufacturers are interested to manufacture a pump with more efficiency. By Computation Fluid Dynamics (CFD) the parameters effects studied to improve its performance and durability. One of the innovations of the CFD designing is that the pump impellers are the now replaceable to old install pump to increase its efficiency increased. This avoids the need of replacing the whole pump set up. The industrial centrifugal pump is on the same track in redesign make them assemble forever maintenance.
Multistage centrifugal pump high-pressure discharge pumps constructed to produce high pressures that nearly meet the pressure of reciprocating compressors. However, it should be equipped with surge tank, air valve and pressure relief valve for safety.
Centrifugal pumps operation
The performance and duty of centrifugal pumps operation in series is explained below by pumping theory. To know centrifugal pump working, its parts, selection and troubleshooting can be understood from below presentation. PPT of Centrifugal pumps operations, selection, types and performance. This includes centrifugal pump curve application in the determination of centrifugal pump efficiency
For same casing different type of impellers like the paddle, closed/open or propeller types can be fitted. Each performance is unique with respect to fluid they handle. Impellers blade angle is very crucial in designing it manipulates power consumption and pumping head. Its surface smoothness has a great impact on the lifespan of the pump.
Rule of thumb:
- Pump performance drops directly with the increase in fluid viscosity, impeller corrosion.
- Hydraulic efficiency drops with an increase in pumping head and power consumption.
Frequent problems with the centrifugal operation:
- Gasket leak
- Bearing failure
- Impeller corrosion
- Pump trips
- Negative pressure build up
Centrifugal pumps selection:
|Pumping medium||Suitable pump MOC type/ impellers|
|Acidic/ Corrosive||Polymer impeller centrifugal pump|
|Basic/ Corrosive||Polymer with blade/paddle impellers|
|Slurry/ viscous||Axial ﬂow impeller /Helical screw|
|Paste/ denser||Gear type|
|Colloidal||Stainless steel casing and impeller|
|Emulsion||Volute casing and open impeller|
|Electrolytic||Volute casing with closed impeller|
|High-temperature||Cast iron casing with blade type impellers|
|Low temperature/ cryogenic||Polymer with high duty smooth blades|
|Gas-liquid dispersion||Anti-cavity type system pump|
Scientific discoveries in centrifugal manufacturing units:
Scientifically a fluid can be transported from one level to another level if kinetic energy is added. This ideology brought up the application of centrifugal action induced into the fluid. By the geometric shape of the volute, fluid passes along the impeller towards the volute surface and gain kinetic energy. Fluid moves towards the discharge with high pressure than the suction.
Primitive centrifugal pumps have a leakage problem between the gaps of rotating shaft and the casing. It led to another scientific discovery of mechanical seals. All modern pumps are fitted with graphite or polymer facing mechanical seals.
Engineering designs of centrifugal pumps for unique application:
Engineering a system that induces kinetic energy to the fluid and makes it move from low-pressure level to high pressure brought the centrifugal pump by rotation technique. Centrifugal pump design is made based on the fluid is going to handle and duty requirement. The cryogenic centrifugal pump is used for pumping liquids that are at negative temperature.
Variable speed drive system: This is awesome engineering technique of controlling the motor speed to enhance the power saving.
Application of centrifugal pump for continuous operations:
- Water distribution system
- Oil and gas industries
- Power plants
Technology that improves the performance of centrifugal pumps:
CFD is a top simulation and design tool used for study the effects and factor that influence the operation of Centrifugal pump. The analysis is done for flow behaviour, the influence of geometric parameters. An equation like Reynolds-averaged Navier–Stokes is the best suitable equation and k-e two-equation turbulence model study the behaviour of fluids.
Concepts that require better research and design for better centrifugal pumps operation:
- Mechanical seal