Understanding The Features That Determine Dripper Success

Key Features Defining Dripper Success in Irrigation Systems  

When technical dripper data is shared, we are confronted by terms that describe certain engineering features, namely K (A); X (B); KD; K (Turbulence coefficient), and Filtration area. These features determine how well a dripper does its job. Understanding them enables us to compare how different drippers do the same job.

Remember the following to navigate technical data:

K (A): Flow rate constant

This is a number specific to each dripper, which is used in flow rate calculations.

X (B): Pressure exponent - The lower the better

A lower pressure exponent will eventually translate to less flow variation along the dripline. This will allow you to use smaller pipes at lower costs while ensuring greater uniformity in water delivery.

KD: Head Loss

This value describes the extent to which the dripper impedes the flow and increases pressure loss in the dripline. It is influenced by dripper size and pipe diameter. The KD of a dripper can be considered neither a disadvantage nor a disadvantage.

K: Turbulence coefficient - The higher the better

A higher turbulence coefficient (K) translates to a more turbulent flow path in the dripper, reducing the clogging risk. Nonetheless, factors such as labyrinth depth, width, length (number of teeth), and design and manufacturing excellence are determining factors on how efficient the dripper is at keeping itself clean.

Depth and width of the labyrinth: The wider and deeper, the better

Length of the labyrinth: The shorter, the better

Filtration area: The bigger the better

The larger the area of a dripper’s filter, the more area is available for contaminants to accumulate therein and the longer it will take for contaminants to completely cover the filtration area. Therefore, the dripper with the larger filtration area comes with longevity benefits.

Let's learn more about the turbulence coefficient and its impact

According to Chandrakant Ramani, Product Manager at Netafim India, a good quality dripper emits a predetermined flow rate that is accurate and constant over its intended lifespan. To achieve this goal of efficiency, a dripper must be kept clean. A dripper’s ability to stay clean is determined by the turbulence coefficient and the effective filtration area. 

Remember, a dripper needs to reduce its inlet pressure from 1 bar to 0 bar and get 1 ℓ/h through it. A complicated mathematical equation explains the pressure difference from the inlet of the dripper flow path to the outlet. All we however need to understand is that the pressure difference comprises two aspects:

• Turbulence
• Friction loss

Pressure loss = turbulence + friction loss

It is important to understand the interaction between these two aspects. Jerry explains that the less turbulence the dripper can create, the more it has to resort to friction loss to create the necessary pressure loss. The more turbulence (the greater the value of K), the better the dripper is at keeping clean.

Consider the following facts:

• The greater the depth and the width of a dripper labyrinth, the better. A wider and deeper labyrinth results in a higher K value.
• The shorter the length of the dripper labyrinth, the better. The addition of teeth to dripper labyrinths creates turbulence, resulting in a turbulent flow and not a laminar flow. This keeps particles in suspension, allowing them to pass through the dripper. A shorter labyrinth has fewer teeth, resulting in a higher turbulence coefficient (K). The less teeth we have to use to create the necessary friction loss, the better.

There is one more secret factor that makes the difference between a good-quality dripper and a poor-quality dripper if technical aspects such as labyrinth width, depth, length, and the number of teeth are equal.

This is the design and manufacturing of the dripper. If the design and manufacture of a dripper labyrinth is not optimal, the turbulence coefficient (K) will be lower and the dripper will need to resort to friction loss to achieve the required pressure loss.

If the teeth of a labyrinth do not have razor-sharp edges, more teeth must be added to the labyrinth to create more friction loss. This will not only lower the turbulence coefficient further but may also mean that the filtration area must be smaller.

Netafim Drippers Have:

• Razor-sharp labyrinth teeth
• Fewer teeth in the labyrinth
• Shorter labyrinths
• High turbulence
• Large filtration area

What is in it for you?

A farmer depends on a dripper’s ability to supply water uniformly. This depends on the dripper’s ability to remain clean, which relies on the amount of turbulence.

An irrigation company knows that it needs to provide quality irrigation systems. A clean dripper requires less maintenance, which saves money and labour and means you have less to worry about its performance and efficiency.