Irrigation Pumps
Of all the inherent risks farmers must contend with - frost, insects, weeds, and disease--insufficient rainfall may cause the most trouble. A reliable irrigation system, however, can help balance the unpredictable forces of nature.
A critical component of any irrigation system is the irrigation pump. Because it has several advantages over other fuels, propane is widely used to power irrigation pumps in all types of agricultural applications.
- Environmental benefits
- Propane pumps can produce the same amount of power as gasoline or diesel engines, but with fewer emissions.
- Propane presents minimal risks to livestock, aquifers, ground water supplies, and soil because it is nontoxic and insoluble in water.
- Propane will not leave the dangerous and sometimes toxic residues that may be left by liquid fuels.
- Operational advantages
- A propane engine¹s speed, or RPM, can be adjusted up or down depending on irrigation need. Unless specially equipped with variable speed drives, electric motors operate at a constant speed.
- Longer life: Engine parts and oil remain cleaner much longer.
- Greater storability: Propane can be stored for extended periods of time, while gasoline or diesel tends to turn rancid over time.
End Suction Centrifugal Pump
Types
Most propane-fueled irrigation pumps are centrifugal pumps, of which there are three basic types:
- End suction pumps are the most common type. They are installed (either horizontally or vertically) on a pad above the high-water level.
- Deep well turbine pumps and propeller pumps are mounted under water. Water is pumped up a shaft by a motor.
- Turbine pumps are used primarily for larger pump applications.
- Propeller pumps are used for low-lift, high flow-rate conditions, but multi-stage pumps are available.
Comparison of Propane Pumps
| Type of Pump |
Advantages |
Disadvantages |
| End Suction Pump |
- High efficiency over a range of operating conditions
- Simple, economical and easy to install
|
- Suction lift is limited - needs to be within 20 vertical feet of water surface
|
| Deep Well Turbine Pump |
- Adapted specifically for wells
- Provides efficient high flow rates
- No priming needed
- Can be used where water surface fluctuates
|
- Higher initial cost than end suction pumps
- Difficult to install, inspect, and repair
- Repair and maintenance more costly than for end suction pumps
- Impellers must be periodically adjusted
|
| Propeller Pump |
- Simple construction
- Suitable for portable operation
- Efficient pumping at very large flow rate
|
- Not suitable for suction lift
- Intake submergence depth critical
|
Cost
Irrigation systems (including pump selection) must be custom designed and engineered in a total package to meet the physical characteristics and requirements of each farming operation. The total cost will depend on specifics, such as crop, climate, soils, and water availability. Propane pumps are comparable in price to diesel and gasoline pumps but may qualify for government rebates offered specifically for equipment powered by alternative fuels.
Research and Development
The Propane Education & Research Council funded the development of the "Jasper" engine with TermiNOXTM, an exceptional solution for providing low-emissions, high-powered energy for pumping irrigation water. The propane Jasper engine, developed jointly by Jasper Alternative Fuels of Indiana and Engine Control Systems of Canada, burns 60 percent cleaner that its diesel equivalent. The California Air Resources Board certified the engine in February 2001.
