Uniformity in Spot-Spitter Systems
Nonuniformity is your enemy if you operate a nursery or a grow operation. If some plants get more water than others when you irrigate, you need to run your system long enough to satisfy the plants in your lowest flow rate containers. That means plants in your highest flow rate containers are over irrigated - wasting water, nutrients and money. Even worse, over-irrigation negatively affects plant health. Pressure Compensating Spot-Spitter PC Assemblies give your operation the well-known Spot-Spitter spray pattern, while ensuring every plant gets exactly the same amount of water every time you irrigate. Use Spot-Spitter PC Assemblies for your highest value crops and most demanding applications.
The Spot-Spitter PC Assembly
Each PC Assembly includes a “Compensating, No-Leak” (CNL) barbed flow regulator on one end which plugs directly into your supply lateral, and a 3 or 4 foot length of spaghetti tubing which connects to a Spot-Spitter on the other end. Compensatingmeans that each Spitter outputs the same flow rate at any line pressure between 25 and 60 psi. No Leakmeans flow shuts off whenever pressure is below 10 psi, so all Spitters on each zone turn on and off simultaneously when you irrigate.
Advantages of CNL in Spot-Spitter Systems
Without CNL, even a well-designed irrigation system has many sources of nonuniformity. Pressure losses cause plants at the end of each row to get less water than those at the beginning. This can be minimized with large diameter laterals, but then consider that not all Spitters turn on at the same time as the lateral fills up at the beginning of each irrigation set. Again, the plants at the beginning of the line get more water than the plants at the end. This is a big challenge in high-frequency irrigation (several short irrigation sets per day) where fill-up time can be a significant percentage of the entire irrigation time.
Uniformity without CNL is an even bigger challenge if your rows are not perfectly level. Plants at the lowest point of each row get over-irrigated, first because pressure is higher at the lowest points, and second because your lines drain to the lowest point each time you turn your system off. In some layouts on sloping terrain good uniformity without CNL is simply not possible.
Primerus PC Assemblies solve all of these problems and deliver the same amount of water to every plant in your operation. If pressure is higher at the beginning of each row than at the end, pressure compensation keeps flow rates the same. Lateral fill-up time doesn’t affect uniformity because all Spitters turn on simultaneously when the lateral is completely full and up to 10 psi. Finally, water does not drain to the low points because flow shuts off as soon as pressure turns off – laterals remain full between irrigations.
Spot-Spitter PC Options
The PC Assembly is available in two flow capacities to cover most of the Spot-Spitter line. The Low Flow PC Assembly works with the Light Green, Orange, Brown and Grey Spitters. The High Flow PC Assembly works with the Dark Green and Blue Spitters. Currently there is no PC Assembly that works with the Black Spitter.
When to use PC Assemblies
PC Assemblies can add significant cost to your system so they should only be used if needed. As an example, the combined price on Grow Irrigation for a 48” pre-cut spaghetti tubing length and a Spot-Spitter is $.261 while a 48” PC Assembly and a Spot-Spitter is $.585 – about double the cost. However, if you your layout includes large elevation changes or if you are high frequency irrigating, PC Assemblies may be the only way to get the uniformity your crops need. And the higher value your crop, the more critical irrigation uniformity is.
The Spot-Spitter PC Assembly can be an important tool for improving irrigation system performance if it is used in the right applications.