Caudal offers a wide range of drippers to meet all our customers’ needs. The PC700 AS is one of them. It is a cartridge-type, self-compensating, anti-suction dripper integrated into the pipe. It offers a wide range of flow rates: 1.1 l/h, 1.6 l/h, 2.2 l/h and 3.8 l/h. We fit it to 16 mm, 20 mm and 22 mm pipes, with wall thicknesses ranging from 0.63 mm to 1.2 mm.
As this is a flat or disc-type dripper, its design means that the pressure losses caused by the dripper itself being inserted into the pipe are lower than with other drippers, which allows us to use longer runs.
It is a self-compensating dripper, which means that within its working pressure range of 0.7 to 4 bar, the flow rate remains constant even if the pressure varies. This makes it ideal for sloping terrain and/or long runs, as in both cases the pressure drops that occur are significant, and if the dripper is not self-compensating, there will be considerable variation in flow rates between different points in the system. This dripper ensures that all plants receive the same amount of water, regardless of where they are located within the irrigation sector. Pressure compensation is achieved by a silicone membrane (resistant to agrochemicals) which opens or closes the water flow in a modular manner when the pressure inside the dripper varies.
The anti-suction effect is caused by the design of the dripper, which ensures that water drains slowly from the pipes once we stop watering. This prevents the suction that occurs in the pipes as they empty of water and fill with air. This air enters through the perforations in the pipe from which the water emerges. If the pipes empty too quickly, the air entering through these perforations carries water containing suspended particles, which causes the dripper to become blocked. Fitting air vents at the highest points and at specific locations in the system will also prevent suction. The anti-suction effect is ideal for subsurface drip irrigation (SDI).
The RGS is a very interesting irrigation system which promotes water savings by reducing losses due to evaporation and runoff. However, when burying pipes fitted with drippers, it is essential to use drippers that guarantee they will not become blocked, as it is not easy to detect blockages when the drippers cannot be seen directly. To this end, the dripper must be anti-suction, have a good filtration system and incorporate a mechanism to prevent roots from entering through the dripper holes (the Rootguard® system, which we will discuss in a future article). The anti-suction feature is also recommended for surface irrigation to prevent soil particles from entering the system, particularly in soils with fine particles.
Finally, the filter’s self-cleaning mechanism and the labyrinth design of the PC700AS help to prevent the inside of the dripper from becoming blocked. In any case, we must always equip our system with preventive measures that operate during every irrigation cycle to prevent particles from entering the pipes. We recommend filtration systems that prevent the entry of particles larger than 150 microns or 100 mesh.
Our PC700AS dripper offers all these features, which, combined with its low coefficient of variation (CV), make it a versatile, robust and reliable dripper.
Manuel Gómez Carmona
Agricultural Engineer specialising in Water Resources.
