China's commonly used water-saving irrigation methods include canal seepage prevention, sprinkler irrigation, micro-sprinkler irrigation, seepage irrigation, and drip irrigation, especially the majority of which is drip irrigation. The quality of irrigation is directly influenced by the quality of the dripper heads, and a considerable quantity is required. There are various types of dripper heads, and selecting the right one has become one of the necessary courses for farmers.
The dripper heads mainly refer to a device that transforms pressure water flow in the capillary into dripping or fine stream shape through channels or orifices. The primary criteria for selecting the dripper heads in drip irrigation planting include product manufacturing quality, terrain, crop type and planting spacing, soil properties, and so on.
Drip irrigation system water dispensers have tube-mounted dripper heads and internal inlaid dripper heads, turbulent flow dripper heads, laminar flow dripper heads, as well as pressure compensating dripper heads and non-pressure compensating dripper heads.
According to the method of connection between dripper heads and capillaries
① Tube-mounted dripper heads (vertical installation): The structure is basically the same as the inter-tube dripper heads, except that the other end is closed and the threaded core can be screwed in and out for rinsing or adjusting the flow rate. The one with long threads has a flow rate of 7.5 L/h, and the one with short threads can reach 9.5 L/h.
② Inter-tube dripper heads (horizontal installation): The inter-tube dripper heads manufactured in China have the channel width of 0.75-0.90 mm and a length of 50-60 cm. At an atmospheric pressure, the rated outflow rate is 2-3 L/h.
③ Internal inlaid dripper heads (spiral dripper heads): This dripper heads are made of polypropylene small tubes with the diameter of 1 mm coiled into a spiral shape, also known as filament dripper heads. Their working pressure is 0.7 kg/㎠, and the flow rate is 0.9-9 L/h. By changing the number of spiral turns, the flow rate can be adjusted.
According to the classification of dripper heads flow state: turbulent flow dripper heads and laminar flow dripper heads (porous capillary, double-chamber tube, micro-tube)
According to hydraulic compensation performance, dripper heads can be divided into two types: non-pressure compensating dripper heads and pressure compensating dripper heads
① Pressure compensating dripper heads use the effect of water flow pressure on the elastic body inside the dripper heads to change the shape of the channel (or orifice), that is, when the pressure decreases, the cross-sectional area of the channel gets larger, and when the pressure increases, the cross-sectional area gets smaller, thus making the flow rate of the dripper heads automatically maintain a small range of variation.
② Non-pressure compensating dripper heads use the fixed water flow channel in the dripper heads to consume energy, and its flow rate increases with the increase of pressure.
Reduce the loss of fertilizers, nutrients, and water;
Keep the water in the field capacity;
Reduce weed growth; by controlling the output of each nozzle, the distribution is uniform;
The labor cost is lower than that of other irrigation methods; the variable supply can be adjusted by valves and dripper heads;
Keep the leaves dry and reduce the risk of diseases;
The pressure is usually lower than that of other types of pressurized irrigation, making it a lower energy cost option.