Smithco Turf Spraying Guide - Manual (Page 5)

1 APPLICATION
A. – PUMPS USED FOR SPRAYING TURF
he type of pump selected for the spraying is usually the determining factor in selecting
pressure variables used in spraying tasks.
Most dedicated spray vehicles (e.g., Spray Star 1600 & 3000, Toro Multipro 1100 & 5500) are
fitted with Centrifugal pumps. These are known as high volume/low pressure pumps. Typically 60-70
gallons of flow per minute at pressures up to 100 PSI.
 Characteristics of Centrifugal pumps:
Positives
1. They are relatively inexpensive.
2. Easy to replace and rebuild.
3. Can be pumped against a closed system, as they will bypass within the
volute.
4. Has a relatively small size to fit in many places.
5. Requires little horsepower to run.
6. Can use less expensive hydraulic agitation due to high flow rates.
Negatives
1. All the material pumped passes through the heart and critical components, so wear can be a
factor if a lot of abrasives (wetable powders) are used.
2. Considered a “throw-away” pump by a lot of end users.
3. Low Pressure means it cannot be used in some applications.
The other most common pump used is the Diaphragm-Piston pump. They are considered low
volume/high pressure pumps. Typically these will have volumes of 10, 14 or 20 gallons per minute with
pressures as high as 700 PSI. These are considerably more expensive.
 Characteristics of Piston-Diaphragm pumps:
Positives
1. All the material pumped passes through a special chamber, separated from critical components
by a rubberized diaphragm, so wear is not a factor if a lot of
abrasives (wetable powders) are used.
2. Mechanical parts of pumps (piston, gears, etc.) are enclosed
in an oil bath for lubrication and protection.
3. Usually has air-dampener included reducing pulsation in lines.
4. Useful in wider applications because of high-pressure
capabilities.
5. Easy to rebuild.
6. Considered a better pump by many end users.
Negatives
1. They are relatively expensive.
2. Much larger profile so harder to fit in manufacturing process.
3. Requires more horsepower to run.
4. Often requires mechanical agitation due to small flow rates.
5. Usually much noisier for operator environment.
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