Liquid fertilizer pump and delivery system
Fertilizer pump
 
Fixed-rate CDS-John Blue piston pump

Fixed-rate CDS-John Blue piston pump

Fixed-rate Demco double-piston pump

Fixed-rate Demco double-piston pump

The 12 and 16-row 1770NT and 1790 Planters utilize a CDS-John Blue ground-driven piston pump for liquid fertilizer.  Both fixed-rate and variable-rate piston pumps are available.  The positive displacement of the single piston, variable stroke pump ensures consistency in the fertilizer delivery row-to-row.  Application of fertilizer is not dependent on ground speed and is not affected by viscosity of fertilizer solutions, which is an advantage of this pump compared to the squeeze pump.
 
The 24-row 1770NT comes with half-width disconnect capabilities. The fixed rate system utilizes a Demco double-piston pump.  The variable rate system utilizes two CDS-John Blue piston pumps.
 
The piston pump is constructed of cast iron with stainless steel components to reduce corrosion. Components that are subjected to abrasion are chrome-plated for increased wear. Strainers are used to trap foreign material to reduce plugging.
 
Following are the maximum fertilizer rates that can be achieved by each model.


 Model

 Fixed-rate piston pump

 Variable-rate piston pump

 1770NT 12-Row

 37.6 gallons/acre

 37.6 gallons/acre

 1770NT 16-Row

 37.6 gallons/acre

 37.6 gallons/acre

1770NT 24-Row

 31.0 gallons/acre

 47.3 gallons/acre

 1790

 28.4 gallons/acre

 28.4 gallons/acre


Following are the minimum fertilizer rates that can be achieved by each model.

 Model

 Fixed-rate piston pump

 Variable-rate piston pump

 1770NT 12-Row

 2.4 gallons/acre

 2.4 gallons/acre

 1770NT 16-Row

 2.4 gallons/acre

 2.4 gallons/acre

1770NT 24-Row

 3.2 gallons/acre

 2.7 gallons/acre

 1790

 3.3 gallons/acre

 3.3 gallons/acre


NOTE: For better fertilizer flow consistency when operating the fertilizer system at low rates, this might require some modifications to the delivery system.
Fertilizer rate chart located on planter

Fertilizer rate chart located on planter

The system design of the piston pump makes for easy operation and adjustment. The chain-driven pump with a double sprocket assembly provides easy changeover from high to low fertilizer application rates. The application rate of the liquid fertilizer is set by referring to the rate decal and adjusting the pump setting.  Fertilizer rates on planters equipped with variable rate fertilizer can be adjusted from the GreenStarTM display, or rates can be controlled automatically via prescriptions written in ApexTM.

 
Delivery system
 
Piston pump with flow divider

Piston pump with flow divider

The function of the delivery system is to deliver consistent amounts of fertilizer to each opener.  Two types of delivery systems are available for the piston pump on 1770NT and 1790 Planters: manifold (high-pressure) and flow divider (low-pressure) .  The high pressure manifold is used in conjunction with the unit-mounted single disk opener, which is an injection opener.  After the coulter slices a trench a nozzle located behind the coulter injects fertilizer into the ground.  Different sizes of nozzles are utilized depending on fertilizer rate and ground speed.  The flow divider, located immediately after the piston pump, is a low-pressure system that is utilized with the frame-mounted, single-disk fertilizer opener and unit-mounted, double-disk fertilizer opener.  The internal components of the flow divider distribute the fertilizer in equal amounts to each opener.
Check valve

Check valve

Check valves, located just before the opener, improve row-to-row variance and eliminate the leaking of fertilizer from the openers when the planter is raised.  Check valves are included with all fertilizer systems when the pump is ordered with the delivery system.  On high pressure systems a 10-psi check valve is utilized.  On low pressure systems a 1-psi check valve is utilized.
 
Last Updated : 01-Apr-2010