Sand Filter: An Ideal Choice for Improving Irrigation Water Quality

Sand filters are commonly used as primary filters, utilizing quartz sand as the filter medium. Under certain pressure, water with higher turbidity is passed through a certain thickness of granular or non-granular quartz sand, effectively trapping and removing suspended solids, organic matter, colloidal particles, microorganisms, chlorine, and some heavy metal ions from the water. This results in reduced water turbidity and improved water quality, making it a highly efficient filtration device.

Structure

The structure of a sand filter is simple and efficient, mainly consisting of the following parts:

Inlet: Water intake
Sand inlet: Adding sand filter media inside
Water distributor (distribution plate): Evenly distributing feed water to prevent water flow from concentrating in one area
Sewage chamber: Collecting debris and suspended particles intercepted during the filtration process
Sand filter layer: Trapping suspended impurities
Water collector: Collecting filtered clean water
Outlet: Water outlet
Manhole: For inspecting and cleaning the interior of the sand filter

Features

The materials and design used in the product ensure high safety performance and durability.
The system operates with high efficiency, minimizing the frequency and intensity of maintenance.
The automatic backwash filter element minimizes water consumption to the greatest extent.
Large filtration area with low backwash pressure.
Easy to transport and install.
Configured according to parameter or space compatibility, with 12V or 220V automation, addressing special low and high-pressure installations.

Working Principle

Filtration Stage:

When the system is in the filtration state, pressurized water flows from the filter tank inlet into the water distribution system, reaching the sand filter layer evenly. As the water flows through the sand filter layer, suspended solids are trapped by the filter media. At the bottom of the filter, there is a water collector with slits, which evenly collects the filtered clean water and allows it to flow out of the filter.

Backwash Phase:

As impurities continuously accumulate in the sand filter layer, the pressure loss increases. When the pressure differential reaches a certain set value or the set cleaning time is reached, the system will automatically switch to the backwash state. Pressurized water enters the sand filter layer through the water collector, scouring it to dislodge the trapped contaminants and discharge them from the filtration system. After backwashing for at least 2 minutes, the valve automatically switches the system to the filtration state.

Specifications

Diagram of the dimensions of 2 sand filters

Table 1: Dimensions of Sand Filter
Model	Size (mm)
Model	D	A	B	C	E	F	K
SF1-2	600	700	130	240	1450	1215	1330
SF2-2	700	800	140	240	1580	1305	1520
SF2-3	700	800	140	300	1580	1305	2320
SF3-2	800	900	140	300	1620	1345	1720
SF3-3	800	900	170	300	1695	1395	2620
SF4-2	900	1000	140	300	1660	1385	1920
SF4-3	900	1000	170	300	1740	1440	2920
SF5-2	1000	1150	170	300	1785	1490	2120
SF5-3	1000	1150	200	300	1900	1550	3220
SF6-2	1200	1400	170	300	1925	1593	2620
SF6-3	1200	1400	200	380	2005	1648	4020
SF6-4	1200	1400	200	380	2025	1750	5420

Table 2: Technical Parameters of Sand Filter
Model	Sand Tank Diameter (mm)	Number of Sand Tanks	Maximum Pressure (bar)	Filtration Area (m²)	Backwash Flow Rate (m³/h)	Flow Rate Range (m³/h)
SF1-2	600	2	10	0.6	15	30–50
SF2-2	700	2	10	0.8	20	50–70
SF2-3	700	3	10	1.2	20	70–90
SF3-2	800	2	10	1.0	25	60–80
SF3-3	800	3	10	1.5	25	90–130
SF4-2	900	2	10	1.2	35	90–100
SF4-3	900	3	10	1.8	35	120–150
SF5-2	1000	2	10	1.6	40	90–100
SF5-3	1000	3	10	2.4	40	130–150
SF6-2	1200	2	10	2.2	50	140–180
SF6-3	1200	3	10	3.3	50	150–250
SF6-4	1200	4	10	4.4	50	200–350