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Teej jet boom pilot section control/ redball sprayer
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tedbear
Posted 7/4/2024 06:05 (#10797687 - in reply to #10796079)
Subject: RE: Teej jet boom pilot section control/ redball sprayer


Near Intersection of I-35 & I-90 Southern Mn.
When switching from a manual system to an automatic system attention needs to be made to the control valve style.

Many spray systems use a butterfly type control valve to control the rate. There are two general styles of plumbing that can be used.

The most straight forward method is to place the control valve in the product line after the flow meter to alter the restriction to the section valves and the ground. This is referred to as as "inline" or a "throttling" arrangement. It directly controls the flow rate.

Another plumbing arrangement uses a Tee prior to the flow meter with the control valve plumbed into one the branches of the tee. After the control valve that flow is directed back to the tank or inlet of the pump. This is referred to as "bypass" control. It indirectly controls the flow rate to the ground by providing an alternative low pressure route back to the tank or pump.

Either of these plumbing arrangements can be used with an automatic rate controller. There are sometimes advantages to using one or the other, BUT in either case the control valve must be the style that has working limit switches. These limit switches as the name implies "limit" the range of travel of the butterfly.

Many low end entry level systems where the operator controls the control valve manually do NOT have limit switches in them. This is not much of a problem with a simple systems since the operator soon figures out that if he pushes INCREASE too long, the pressure actually starts to decrease because the butterfly has gone past the maximum point. An automatic system is not able to "figure this out" and therefore a butterfly control valve must have working limit switches.

As an example, Raven makes both styles. They have a butterfly control valve without limit switches for their low end manual systems and butterfly control valves with limit switches for their automatic controller systems.

To determine if your control valve has limit switches, connect it directly to a 12V source and ground. The motor should run for a bit and then stop. Reversing the wires should cause the motor to run again but in the opposite direction and then eventually stop. The butterfly should travel from fully closed to mostly open at the limits. It should take about 8 seconds to go from one extreme to the other. If your valve behaves this way it is suitable for an automatic rate controller system.

If the motor continues to run and the butterfly goes round and round, your control valve is not suitable for the change.
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