• Pump viscosity correction
• Impeller cuts
• How to change the pump performance
• Centrifugal pump introduction
• Cavitation
• Right impeller selection
• Pump installation
• Vertical turbine pump
• Tops for specifying pumps
• Determine between end suction pump and double suction pump
• Understanding the NPSH
• Axially split case pump

• Axially split case pump
• Single stage centrifugal pump
• Multisage ring section pump
• Submersible & sewage pump
• Petroleum chemical pump
• Barrel (double) case pump
• Self-priming pump
• Vertical turbine pump
• API610 / ISO13709 Pump

The performance of centrifugal pumps will vary when viscous liquids are pumped. For medium and high viscosities, the power requirement increases considerably, whilst the head and to a lesser extent the flowrate, is reduced.

With the aid of correction diagram mentioned below, the characteristics of a centrifugal pump pumping viscous liquids can be calculated providing the characteristic for pumping water is known. Conversely, the diagram may also be used to select a pump for given requirements.

The correction factors established from the diagram are sufficiently accurate for general application within the limits given. If more accurate values are required, then a test should be performed with the particular liquid.

Due to the considerable loss of efficiency when pumping viscous liquids when using centrifugal pumps, it is recommended that other types of pump be considered (e.g. rotary positive displacement pumps), which could give more economical running costs. The limits for centrifugal pumps are:

For discharge nominal diameter:
< 50 approx 120 to 300 mm²/s
< 150 approx 300 to 500 mm²/s
> 150 approx 800 mm²/s

Like all other pump munuacturers on the world, Hankia Pump also establish the performance curve of the petroleum chemical pumps, based on clean water. But there is conflict that petroleum chemical pumps are usually applied to liquid with high viscosity and high temperature. Therefore tt is significant the correct the petroleum chemical pumps' performance data by referring to the data based on clean water that is already tested and known. The following chart give the correction factors for petroleum chemical pumps that is apporved being effecitive in general application.