Shallow Sand Filter

Product Overview

The Shallow Sand Filter consists of multiple standard high-speed sand filter units, each equipped with a water distributor, a water collector, and an automatic control valve. It enables individual backwashing of the standard high-speed sand filters during normal system operation, under fully automatic program control. It offers advantages such as low backwash water consumption, convenient equipment installation, and ease of operation. The unit features a large flow rate and requires no maintenance. Depending on user requirements, it is available in two series: vertical and horizontal. It is suitable for water treatment in industrial and municipal circulating water systems.

Application areas

① Filtration of industrial water requires a certain level of system integrity to ensure water quality, removing impurities to meet the needs of production processes.

② Filtration system for industrial circulating water.

③ Hotel and catering industry: efficient filtration of potable water, well water, and other sources.

④ Agricultural irrigation, particularly suitable for high‑flow water sources with low impurity levels, such as farmland irrigation and the watering of park and golf course lawns.

⑤ Treatment of industrial process water in the food processing industry, the paper-making industry, and power plant cooling water systems.

⑥ Pretreatment of purified water for industrial and medical applications.

⑦ Recirculation of industrial process water and treatment of industrial wastewater.

⑧ The aquaculture, swimming, and water park industries.

Process Principle

Filtration Mode: When the system is in filtration mode, unfiltered water is evenly distributed through a unique water distributor and flows laminarly through the filter’s media bed (refined, uniformly graded quartz sand or sea sand). As the water passes through the media bed, impurities are retained within it. At the bottom of the filter, multiple evenly spaced collectors gather and discharge the filtered water uniformly. This laminar-flow filtration allows the filter to operate at high flow rates while still achieving excellent filtration performance.

Backwash mode: As impurities continuously accumulate within the media bed, the internal head loss steadily increases. When the inlet–outlet pressure drop reaches the set threshold, the system automatically activates the sensing device to switch to backwash mode. Once backwashing of one unit is complete, the three-way valve reverses the water flow direction, enabling sequential backwashing of each unit and facilitating the removal of accumulated contaminants.

When the system is in backwash mode, filtration continues: the standard unit sand filter undergoing backwashing ceases filtration, while the other standard unit sand filters remain in operation. A portion of the filtered clean water is diverted to backwash the sand filter, with the remainder delivered to the user. The backwash wastewater is discharged through the backwash drain port of the three-way valve. In this high‑speed, fully automatic, highly efficient sand filtration system, a specially designed water collector enables the media to rub against one another, maximizing backwash efficiency and minimizing the volume of backwash (clean) water required, while eliminating media loss during backwashing. Each standard unit sand filter is backwashed for two minutes; once backwashing is complete, the three-way valve returns to the filtration position, and the next standard unit sand filter prepares to enter backwash mode.

Product Features

• Compact in size, it occupies minimal floor space, is easy to install, and can be mounted indoors or outdoors, as well as in multi‑level configurations, offering excellent adaptability.
• High filtration rate, low pressure drop—completely addresses the issues of slow filtration rates and limited flow in conventional mechanical media filters.
• Modular design, compact footprint, minimal piping, and reduced capital investment. The floor space is reduced by more than one-third, and the piping workload is cut by over half.
• Manual, semi-automatic, and fully automatic backwashing options are available, fully meeting practical requirements.
• High backwash efficiency and short backwash duration (water consumption is approximately one-third that of conventional sand filters).
• 16"-96" – Available in various model configurations; multiple units can be combined, and the processing capacity can be scaled as needed.
• The shell and tubes are fabricated from carbon steel Q235B with an anti-corrosion surface treatment; stainless steel may also be used.
• Other specifications can be customized, and units can be configured according to customer requirements.
• For valve arrangement, small systems may use manifold‑type valves, while large systems typically employ valve manifolds; alternative configurations are also possible depending on specific requirements.
• Electrical control can be implemented via relay-based control or PLC control, with a host‑computer interface provided as an option.

Model Description

1. Product series; 2. Shallow sand; 3. Tank diameter; 4. Number of units

Technical Specifications