Views: 0 Author: Site Editor Publish Time: 2025-05-23 Origin: jf-irrigation.com
Filters impurities such as sand, algae, and organic matter in water, with a precision range of typically 20-300 microns, meeting the needs of different irrigation methods like drip irrigation and sprinkler irrigation. For example, drip irrigation systems require high filtration precision (generally ≤100 microns). Backwash filters effectively prevent dripper blockage, ensuring uniform delivery of water and fertilizer to crop roots.
Case: After applying automatic backwash filters in the drip irrigation system for cotton in Xinjiang, the dripper blockage rate decreased by over 90%, and irrigation efficiency increased by 30%.
No need for manual disassembly and cleaning. The backwashing process is triggered by pressure difference induction or timing, using reverse water flow to flush the filter screen and discharge impurities. Compared with traditional manual cleaning filters, it reduces 80% of manual maintenance costs, especially suitable for large-area farmland or unattended scenarios.
The water consumption during backwashing is only 1-3% of the filtered water, far lower than that of manual cleaning. Meanwhile, the continuous and stable filtration effect avoids frequent start-stop of the water pump caused by blockage, reducing energy consumption. It is estimated that each mu of farmland can save about 50-100 yuan in water and electricity fees annually.
Prevent impurities from wearing irrigation pumps, solenoid valves, sprinklers, and other equipment, extending the service life of the entire irrigation system (by 2-3 years) and reducing equipment replacement costs.
Filter Screen Unit: Mostly made of stainless steel wedge wire screens or sintered screens, which are corrosion-resistant and high-strength, capable of intercepting impurities of different particle sizes.
Backwashing Mechanism: Includes a controller (pressure difference/time trigger), backwashing valve, drain port, etc., driven by hydraulic or electric means.
The backwashing valve opens, and part of the clean water flows back from the outlet, flushing impurities from the inside to the outside of the screen in the reverse direction.
Meanwhile, the drain valve opens, and impurities are discharged with the water flow. The backwashing time for a single screen is about 10-30 seconds, and the entire process does not interrupt irrigation.
Filtration Stage: Water flows into the filter from the inlet, passing from the outside to the inside of the screen. Impurities are intercepted on the outer surface of the screen, and clean water flows out from the outlet to the irrigation pipeline.
Backwashing Stage: When the pressure difference before and after the screen reaches the set value (e.g., 0.05MPa) or the preset time (e.g., 8 hours), the controller starts the backwashing process:
| Scenario Type | Application Characteristics | Typical Crops |
|---|---|---|
| Field Crop Irrigation | Needs to handle water sources with high sand content (such as river water and reservoir water), with large filtration flow (a single device can cover 500-1000 mu), suitable for automated centralized control. | Wheat, corn, rice |
| Cash Crop Drip Irrigation | Requires high filtration precision (≤100 microns) and matches with the water-fertilizer integration system to prevent fertilizer crystallization or organic matter from blocking drippers. | Grapes, strawberries, vegetables, fruit trees |
| Greenhouse Micro-Irrigation | Water sources are mostly groundwater or tap water, but need to filter microorganisms in the water and impurities from pipeline aging, | Flowers, seedlings, high-end vegetables |
| Water-Saving Irrigation in Water-Shortage Areas | Can recycle irrigation tailwater, remove suspended solids in water through backwash filters, and achieve water reuse (water saving rate ≥70%). | Lycium barbarum, cotton in arid areas of Northwest China |
Surface Water (River, Lake Water): High sand content and many impurities. It is recommended to choose a precision of 50-150 microns, matched with a pre-coarse filter (such as a centrifugal filter).
Groundwater: Low sand content but may contain minerals or microorganisms. Choose a precision of 80-200 microns. If the water quality is soft, the filtration process can be simplified.
Reclaimed Water/Irrigation Tailwater: Need to balance the filtration of organic matter and suspended solids. It is recommended to use a precision of 50-100 microns and disinfect regularly.
The flow range of a single automatic backwash filter is usually 50-500 m³/h. For example, a 100-mu drip irrigation field (2 m³/h per mu) requires a device with a flow rate of 200 m³/h.
Note to reserve a 20% flow margin to avoid insufficient water pressure during peak periods.
Pressure Difference Control: More energy-efficient, suitable for scenarios where water source quality fluctuates greatly (such as river irrigation).
Time Control: Suitable for scenarios with stable water quality (such as groundwater irrigation), which can be backwashed at fixed cycles.
It is recommended to choose the "pressure difference + time" dual-control mode to ensure filtration effect.
The main body material is preferably stainless steel (SS304/316) or high-strength engineering plastic, which is corrosion-resistant and high-pressure resistant (working pressure is usually 0.2-1.0MPa), adapting to complex farmland environments.
Regularly check the reading of the pressure difference gauge. When the pressure difference rises to 1.5 times the initial value, inspect whether the backwashing function starts normally.
Observe the backwashing and drainage situation. If too many impurities are discharged, shorten the backwashing cycle or check whether the pre-filter fails.
Disassemble the filter screen every quarter to check for wear. Replace it promptly if damage is found. Use a soft brush to clean stubborn impurities on the screen surface (avoid scraping with hard objects).
Lubricate and maintain the controller and backwashing valve annually to ensure smooth operation of electric/hydraulic components.
In northern regions, when stopping operation in winter, drain the water inside the filter to prevent freezing and cracking. Install thermal insulation layers or move it indoors if necessary.
If the water source contains algae or organic matter, add fungicides (such as sodium hypochlorite) to prevent screen blockage and microbial reproduction.
Hetao Irrigation District, Inner Mongolia: Aiming at the high sand content of the Yellow River water, automatic backwash filters (100-micron precision) were used with centrifugal filters, solving the blockage problem of the 10,000-mu wheat drip irrigation system. The irrigation water utilization rate increased from 50% to 85%, and the yield per mu increased by 15%.
Yunnan Plateau Blueberry Base: High-precision backwash filters (50 microns) were used to treat mountain spring water, matched with a water-fertilizer integration system, avoiding uneven water and fertilizer caused by dripper blockage. The blueberry sweetness increased by 2 degrees, and the yield per mu increased by 200 kg.
