Solution System

N81785-UN-17OCT08

1 - Solution Tank

2 - Suction Valve

3 - Pressure Bypass / Rinse Valve

4 - Rinse Tank Quik-Fill™ Valve

5 - Solution System Quik-Fill Valve

6 - Centrifugal Pump

7 - Fill Strainer (30 Mesh Optional)

8 - Eductor Rinse Valve

9 - Eductor Hopper Valve

10 - Eductor Flow Rate Valve

11 - Agitation Flow Rate Valve

12 - Check Valve

13 - Rinse Tank

14 - Eductor Venturi

15 - Shut-Off/Solution Outlet Valve

16 - Agitation Solenoid Valve

17 - Boom Supply Line Strainer (50 Mesh Standard)

18 - Boom Supply Line Strainer (80 Mesh Optional)

19 - Solution Flowmeter

20 - Orifice Valve

21 - Boom Shut-off Valve

22 - Boom Section Shut-off Valves

23 - Pressure Transducer

24 - Spray Nozzles

25 - Eductor Hopper

26 - Wheel Speed Sensor (Left-hand Front Wheel)

27 - Hydraulic Motor

28 - Proportional Valve

29 - Radar

30 - CCU/SRC

31 - SprayStar Displays

32 - Pump Bleed Line

System Components

The solution spray system consists of solution tank (1), suction valve (2), Quik-Fill valve (5), fill strainer (7), pressure valve (3), centrifugal pump (6), boom supply line strainers (17,18), eductor hopper (25), orifice valve (20), boom section shut-off valves (22), and spray nozzles (4) mounted on the boom.

Solution tank is made from polyethylene and has a capacity of 2,271 L (600 gal). An access/fill cap is located at the top of the tank. At the side of the tank is a clear tube and graduated scale that indicates solution level in liters and gallons. Located at the bottom of the tank is the shut-off/solution outlet valve (15).

The suction valve has two functions:

• Directs solution from solution tank to solution pump.
• Directs clean water from rinse tank to solution pump.

The fill strainer located in the fill line is constructed of a noncorrosive material that should be cleaned as required. The solution pump is a centrifugal type that is driven by hydraulic motor (27). Engagement and disengagement of the pump is controlled by a switch located on the side console. Any air trapped in the pump is allowed to escape through a bleed-off line (32). This helps prevent pump cavitation.

Strainer(s) are located in the boom supply line before the solution flowmeter (19). The strainer(s) remove sediment before it reaches flowmeter and boom valves.

The boom shut-off valve (21) can be closed to aid in cleaning the boom supply line strainer(s) (17,18) and the flowmeter (19).

An orifice valve is located in the boom supply line. It is used to improve the control of the spray rate control system when smaller nozzles are used. The valve is set in open position for medium to high flow rates and in closed position for a flow rate of 100 Lpm (26 gpm) or less.

Agitation jets are in two locations on the bottom of the tank. The jet creates a vigorous fan type agitation throughout the tank to keep chemicals, such as wettable powders, in suspension. The agitation flow rate valve (11) is located under left-hand side of machine near the solution pump and can be adjusted to attain the desired agitation effect. The agitation solenoid valve (16), controlled by a switch on the console, can be used to turn the agitation on and off.

Pressure Bypass / Rinse valve does one of three things:

• Directs rinse water to the tank rinse nozzles
• Directs water or solution directly to the tank when filling sprayer with solution pump
• Stops solution from flowing to solution tank or tank rinse balls when spraying

The eductor flow rate valve (10) directs fill water through a eductor venturi (14) at top of the solution tank to create a vacuum to pull the chemical into the water stream. The eductor rinse valve (8) directs water to the hopper rinse and the jug rinse. The eductor hopper valve (9) allows chemical to be drawn from bottom of eductor hopper to top of solution tank.

Check valves (12) are used in the system to prevent solution from flowing in wrong direction.

Boom section shut-off valves (22) are motorized ball valves that cycle completely open or completely closed. The valves are operated by switches on the operator’s side console.

The spray nozzles, located on the center frame and boom, meter, atomize and dispense the solution into specific patterns. Solution flow is metered by the size of the orifice in the nozzle tip. Within limits, solution flow through a nozzle can be increased or decreased by adjusting system pressure.

Most nozzles are designed for optimum performance at specific pressures. However, the range of adjustment is relatively narrow. Line pressures too high or too low will affect atomizing the solution and create variations in the spray pattern. The solution atomizes when the liquid is forced through the orifice in the nozzle. The shape of the spray pattern is determined by the shape of the orifice.

The rinse tank (13) can be loaded with clean water for rinsing solution system.

System Operation

When the pump is activated, solution is drawn from the solution tank, through the suction valve. The pump pushes the solution through the boom supply line strainers and flowmeter to the boom section shut-off valves, and to the agitation flow rate valve for agitation.

When the boom section shut-off valves are open, the solution flows to the nozzles, where it is atomized and sprayed.

The flowmeter in the boom supply line sends an electronic signal to the CCU/SRC (30), which compares that signal to the operator-programmed application rate. If there is a difference in the signal from the flowmeter and the programmed rate, the compensator in the proportional valve assembly (23) will open or close as needed until the system is stabilized at the target rate.

When the compensator opens, more hydraulic oil is sent to the hydraulic motor, causing the solution pump to increase its flow. When the compensator closes, less hydraulic oil is sent to the hydraulic motor, causing the solution pump to decrease its flow.

The Spray Rate Controller (SRC) provides the ability to maintain application within a range of application rates while changing speeds. Application rate consistency depends on a number of things such as nozzle tip size, application rate, and rate of speed change. The SRC provides quick response, but some differences in application rates can be observed if the operator makes rapid speed changes or operates at the extremes of the solution pressure range.

Principle parts of the SRC system are a speed sensor (either a wheel speed sensor (26) on left front wheel motor or a radar speed sensor (29) at front of machine), the spray rate controller, a variable speed solution pump, flowmeter, and a solution pressure transducer (23). The speed sensor and flowmeter provide speed and flow rate information to the spray rate controller. The spray rate controller provides target (programmed by the operator) application rates by analyzing speed and flow data, and then making appropriate adjustments to the variable solution pump.

The spray rate controller is part of the Chassis Computer Unit/Spray Rate Control Unit (CCU/SRC) located under the floor plate inside the cab. The spray rate controller has an internal warning system that alerts the operator if the actual flow rate varies from the programmed flow rate by 20% of actual or more for 10 seconds. The SRC system is a volume-regulating system, so pressures displayed on the SprayStar display (31) may vary at a given ground speed.

The solution pressure required for a given application rate is determined by speed and nozzle tip size. Before attempting to use the SRC, refer to a nozzle tip calculator or nozzle tip selection charts, and make sure the spray boom is equipped with spray tip nozzles that will provide desired application rates at desired pressures and speeds. Ground speed variation is limited by the operating pressure range of the nozzle tips.

The “Master On/Off” button located on the multifunction control handle is an integral part of the SRC system. When “Off” is pushed, electrical power closes the boom section shut-off valves and the variable solution pump slows to maintain spray-off pressure (as set by the operator).

Solution may continue to spray from the boom for a short period of time after “Master Off” is pushed. This is due to pressure remaining in the line. The time interval that spray will continue flowing depends upon pressure in the spray line, boom hose lengths and routings, nozzle tip size, and use of nozzle check valves. In order to compensate for the boom shut-off lag time, “Master Off” should be pressed prior to reaching the turnrow.

Once “Master On” has been pressed, if the machine is moving slowly or is not moving, the variable solution pump will maintain the minimum solution pressure as set by the operator. This may result in an application rate that is higher than the target rate (programmed by the operator). Likewise, if the machine is moving too fast, the variable solution pump will maintain the maximum solution pressure. This may result in an application rate that is lower than the target rate.