The limitation of a fuel oil pump feeding a burner may often be the suction side. With higher suction lift the "vacuum" in the suction line will evaporate the light fractions of the fuel oil - and the pump starts to choke.
In general there are two types of fuel feeding pumps
- single stage pumps
- double stage pumps
A single stage pump consist of only one set of pumping gears and the lift capacity is limited compared to the two stage fuel pump with double set of pumping gears.
- a single-stage pump is suited for low-level lifts up to 5 - 10 inches of vacuum
- a two-stage pump is suited for medium-level lifts up to 10 - 15 inches of vacuum
Higher "vacuum" levels requires use of separate lifting pumps and dedicated feeding reservoirs to the fuel pumps.
The total "vacuum" in a fuel oil suction line can roughly be estimated to
- 1 inch of vacuum for each foot of lift
- 1 inch of vacuum for each 90o elbow
- 1 inch for each 10 feet of 3/8 inch horizontal suction pipe
- 1 inch for each 20 feet of 3/8 inch horizontal suction pipe
Boiler house topics, fuels like oil, gas, coal, wood - chimneys, safety valves, tanks - combustion efficiency.
Combusting testing of fuel oil and gas burners.
Pot types, gun types and rotary types fuel burners.
Combustion values in Btu/gal for fuel oils No.1 to No.6.
Classification of gas oil based on BS 2869 - Specification for fuel oils for agricultural, domestic and industrial engines and boilers.
Viscosities and densities of ISO - and equivalent SAE grade oils.
Recommended max. flow velocities on the delivery side when pumping light oils.
Viscosities of fuel oils vs. temperature.
Suction Specific Speed can be used to determine stable and reliable operations for pumps with max efficiency without cavitation.
Recommended max. pump suction flow velocity for viscous fluids.
Recommended max. water flow velocities on suction sides of pumps.