DRIPPER COMPARISONS  Introduction 
Drippers Comparison
A farmer and his crop care not about the specifics and technical details of a dripper. It out of the dripper that they care about. They need a dripped supply of water into the  shaped root zone on demand during the life of the crop. This dripped supply may not v decrease over time. It must be accurate and constant over the crop’s life. This is the es Article supplied by Netafim of a dripper to a farmer.  
A dripper is a dripper is a dripper? Not really. We know in reality, that there is a vast d
Introduction The Turbulence Coefficient drippers and specifically dripper quality; sometimes for good reasons and other times  A farmer and his crop care not about the specifics and A dripper’s structural features can be defined as an inlet filter, quality dripper may be defined as one that emits a predetermined flow rate that is acc technical details of a dripper. It is what comes out of the an inlet orifice, a flow path whose shape is a labyrinth with dripper that they care about. Theyconstant over its intended life.   need a dripped supply of teeth, an exit ‘bath’ and finally an orifice that is made through water into the wetted bulb-shaped root zone on demand the wall of the drip line from which the droplet leaves the ARISONS  A method has now been devised to quantify these common features and formulates a score during the life of the crop. This dripped supply may not vary or irrigation system and goes into the root zone. evaluate a drippers quality and make an educated choice that best suits the application in question. Features that contribute to keeping a dripper clean and working are essentially those  decrease over time. It must be accurate and constant over the The concept simply involves two aspects: the dripper’s net filtration area and its Turbulence to the dripper’s quality. The main structural features, such as the filtration area, the la crop’s life. This is the essential feature of a dripper to a farmer. With the exception of the inlet filter, the Turbulence Coefficient. Coefficient embraces all of these structural features of a width, and length, are common to all drippers. These are all measurable. Other featur The Turbulence Coefficient s crop care not about the specifics and technical details of a dripper. It is what comes  A dripper is a dripper is a dripper? Not really. We know in dripper that contribute to dripper quality. In essence, the A dripper’s structural features can be defined as an inlet filter, an inlet orifice, a flow path whose anti�root intrusion and anti�siphon devices are unique to a specific dripper and they ar er that they care about. They need a dripped supply of water into the wetted bulb� reality, that there is a vast difference in drippers and higher theanTurbulence Coefficient, lower the shape is a labyrinth with teeth, exit ‘bath’ and finally an orifice that the is made through the dripper’s wall of drip line fromsensitivity which the droplet the irrigation and goesits intoability the root zone. measurable.  specifically dripper quality; sometimes for good reasons the and to leaves clogging and system the better to maintain its e on demand during the life of the crop. This dripped supply may not vary or  other times not. A good quality dripper may be defined as constant rate over Coefficient its intended life. This achieved by With the exception of the inlet flow filter, the Turbulence embraces all of these is structural features of a dripper that contribute to dripper quality. Inin essence, the higher thethat Turbulence me. It must be accurate and constant over the crop’s life. This is the essential feature  one that emits a predetermined flow rate that is accurate and the vortexes that develop the labyrinth create a self  Coefficient, the lower the dripper’s sensitivity to clogging and the better its ability to maintain its cleaning stream which purges contaminants out of the dripper.  farmer.  constant over its intended life. constant flow rate over its intended life. This is achieved by the vortexes that develop in the labyrinth that create a self-cleaning stream which purges contaminants out of the dripper.
Features that contribute to keeping a dripper clean and The higher the Turbulence The higher thethe Turbulence Coefficient, better the Coefficient, better the quality. To work out thethe Turbulence pper is a dripper? Not really. We know in reality, that there is a vast difference in  Coefficient, simply follow theTo formula below: working are essentially those that contribute to the dripper’s quality. work out the Turbulence Coefficient, simply follow ecifically dripper quality; sometimes for good reasons and other times not. A good  quality. The main structural features, such as the filtration the formula below: 254 ∗ đ?‘ƒđ?‘ƒ ∗ (đ?‘Šđ?‘Š ∗ đ??ˇđ??ˇ)² area, the labyrinth depth, width, and length, are common to may be defined as one that emits a predetermined flow rate that is accurate and  đ??žđ??ž = đ?‘ đ?‘ ∗ đ?‘„đ?‘„² all drippers. These are all measurable. Other features, such s intended life.   Turbulence Coefficient Coefficient as anti-root intrusion and anti-siphon devices are uniqueK to a K - Turbulence P pressure differential through the labyrinth in metres specific dripper and they are not measurable. P - pressure differential through the labyrinth in metres W width of labyrinth water passage in mm ntribute to keeping a dripper clean and working are essentially those that contribute  W- width of water labyrinth D depth of labyrinth passage water in mm passage in mm N number of teethofin labyrinth the labyrinth water passage in mm A method has now been devised to quantify these common D- depth quality. The main structural features, such as the filtration area, the labyrinth depth,  Q labyrinth flow rate in litres per hour features and formulates a score to evaluate a drippers quality N- number of teeth in the labyrinth h, are common to all drippers. These are all measurable. Other features, such as  and make an educated choice that best suits the application in Q - labyrinth flow rate in litres per hour Let us look at how these elements impact the Turbulence Coefficient and thereby the quality of a on and antiâ€?siphon devices are unique to a specific dripper and they are not  question. dripper. Letofus at how these elements impact the Turbulence The depth and width thelook labyrinth: the greater, the better. The concept simply involves two aspects: the dripper’s net Coefficient and thereby the quality of a dripper. At 10 m pressure, the flow rate is 1.0 litre per hour through a labyrinth with 44 teeth and width x filtration area and its Turbulence Coefficient. depth dimensions of 0.60mm x 0.59mm. The resulting Turbulence Coefficient is 7.2.
 
Figure 1. The filter at the inlet to a modern boatâ€?shaped nonâ€?PC dripper 254 ∗ 10 ∗ (đ?&#x;Žđ?&#x;Ž. đ?&#x;”đ?&#x;”đ?&#x;”đ?&#x;” ∗ đ?&#x;Žđ?&#x;Ž. đ?&#x;“đ?&#x;“đ?&#x;“đ?&#x;“)² đ??žđ??ž =
44 ∗ 1.0²
đ??žđ??ž = 7.2
However, increasing the labyrinth depth and width by 0.01mm to 0.61mm x 0.60mm but keeping all other measurements the same, the Turbulence Coefficient would increase to 7.7 đ??žđ??ž =
 
254 ∗ 10 ∗ (đ?&#x;Žđ?&#x;Ž. đ?&#x;”đ?&#x;”đ?&#x;”đ?&#x;” ∗ đ?&#x;Žđ?&#x;Ž. đ?&#x;”đ?&#x;”đ?&#x;”đ?&#x;”)² 44 ∗ 1.0² đ??žđ??ž = 7.7
 
Figure 1. The filter at the inlet to a modern boat-shaped non-PC dripper Figure 2. The labyrinth of a non-PC dripper with the exit ‘bath’ to the left, where a hole igure 1. The filter at the inlet to a modern boat�shaped non�PC dripper  Figure 2. The labyrinth of a non�PC dripper with the exit ‘bath’ to the left, where a h would be made through the dripperline wall for the droplet to exit the irrigation system made through the dripperline wall for the droplet to exit the irrigation syst
 
30
The Overflow - Spring 2019
