||Centrifugal Pumps (non-positive
In centrifugal pumps, spray solution enters through the center of the rotating impeller that's driven at speeds up to 6000 RPM. Spray Solution is forced to the outer edge of the housing. This centrifugal force is what delivers the liquid to the nozzle. Traditionally thought of as low-to-medium pressure pumps, this type of pump can deliver high flow rates. Because centrifugal pumps have minimum surfaces to wear, and no valves, they are very durable; easy to maintain and well suited for pumping abrasive and corrosive materials.
|Chemical Transfer Pumps
||Chemical Transfer Pumps|
For economical and reliable delivery of herbicides and chemicals.
Diaphragm Pumps (positive
Because of their design, diaphragm pumps provide excellent handling of abrasive and corrosive materials. The pumping cylinders are separated from the piston chambers by a synthetic diaphragm. This keeps the spray solution from contacting and corroding the internal pump components. Diaphragm pumps are compact, self-priming and produce medium-to-high pressures with flow rates ranging from 3.5 to 62 GPM. Driven by PTO, electric or gas engines, diaphragm pumps are used for a variety of agricultural, horticultural and pest control spraying applications.
Hand pumps are used by mounting on barrels, trucks or any place fluids need to be transfered. Can be used for applying herbicides, insecticides, fungicides or fertilizers.
Roller Pumps||Roller Pumps
Roller pumps are the number one all-round choice by farmers throughout the world. The rollers revolve inside the pump housing to force the spray solution through the outlet to the nozzle. Roller pumps have a low initial cost and are extremely versatile. Roller pumps are self-priming and easily adapt to PTO or gas engine drives.
|Piston Pumps||Piston Pumps
Piston pumps are not unlike an engine. That is, they have a shaft, pistons and "intake" and "exhaust" valves. On the down-stoke, the inlet valve opens, filling the chamber with solution. On the up stoke, the outlet valve opens, and the piston forces the solution to the nozzle. Piston pumps deliver relatively low flow rate (up to 10 GPM) at high pressure (up to 400 PSI). The replaceable piston cups can be of leather, fabric or Buna-N rubber, depending on the type of solution to be sprayed. They can be driven by PTO, gas engine or electric motor. Their low volume/high pressure capability permits use in general spraying as well as task-oriented applications such as spraying fence rows and ditches and hydrostatic testing.
"Positive displacement" vs. "non-positive displacement"
Most pumps can be divided into to general categories: "positive displacement" and "non-positive displacement. Roller,
diaphragm and piston pumps are positive displacement. That is, the flow from the pump is directly proportional to the pump speed. This
positive flow is why all positive displacement pump hook-ups must include a relief
bypass line between the pump outlet and nozzle-shutoff valve.
Centrifugal and turbine pumps are non-displacement. In these pumps, a rotating impeller creates a centrifugal force that feeds the liquid through the
system instead of capturing and discharging a fixed volume "per stroke" as roller, pistons or diaphragms would do. Therefore, if
the outlet is closed, the impeller simply continues to rotate harmlessly. That is why special relief valves are not required in centrifugal or turbine pump systems.