INTRODUCTION

The filter tank is usually made of high-strength carbon steel or stainless steel, possessing good pressure resistance and corrosion resistance, providing stable protection for internal components. The shallow sand filter bed, as the core part, is formed by carefully selected filter materials such as quartz sand. It has a relatively thin thickness and a shallow distribution characteristic. However, with reasonable laying and configuration, it can efficiently intercept impurities in water. The water distribution system ensures that the water to be filtered is evenly distributed on the surface of the filter bed, making the filtration process more thorough. The water collection system is responsible for collecting the filtered clean water for discharge and use.

The backwash device is the key to ensuring the continuous and efficient operation of the equipment. It can conduct reverse washing on the filter bed regularly or as needed to remove the dirt attached to the filter materials. The control system is like the "brain" of the equipment. Based on preset parameters, such as filtration time and the pressure difference between the inlet and outlet water, it can intelligently regulate operations like backwashing to achieve automated operation without the need for frequent manual intervention. This equipment comes in a variety of specifications and can be flexibly selected according to the water treatment volume and water quality requirements. It is suitable for water filtration in small households, commercial places, as well as large-scale water treatment projects in industrial production and municipal water supply. It is easy to install and operates stably and reliably.

WORKING PRINCIPLE

The working principle of shallow sand filters focuses on the two key links of filtration and backwashing of the shallow sand filter bed. When water containing impurities enters the filter tank, it first passes through the water distribution system and is evenly dispersed. Then the water flows gently to the surface of the shallow sand filter bed.

When the water flows through the shallow sand filter bed, due to the existence of certain pores between the sand grains, impurities in the water with particle sizes larger than these pores, such as sediment and suspended solids, will be intercepted on the surface of the sand layer and in the pores. While water and substances with smaller particle sizes can smoothly pass through the sand layer, be collected by the water collection system and flow out from the outlet, completing the preliminary filtration process and obtaining relatively clean water.

As the filtration continues, the impurities intercepted on the filter bed will gradually increase, which will lead to an increase in the pressure difference between the inlet and outlet water or meet other preset conditions such as the filtration time. At this time, the control system will start the backwash device. Then, the backwash water will rush into the filter bed from the bottom in the reverse direction. The powerful impact force of the water flow will wash up the impurities attached to the filter materials, making them separate from the sand layer. The sewage carrying these impurities will be discharged out of the tank through the special sewage discharge pipeline. After the backwash is completed, the filter bed will return to the normal filtration state, repeating this cycle continuously to ensure the long-term stable filtration effect of the equipment.

MAIN PERFORMANCE AND CHARACTERISTICS

l High-Efficiency Filtration Performance: Although the filter bed is set in a shallow manner, with the reasonable matching and distribution of sand particle sizes, it has an excellent interception effect on common impurities in water such as sediment, suspended solids, and algae. It can significantly reduce the impurity content in water, improve the clarity and purity of water quality, and meet the basic requirements for water quality in different scenarios. It can play a good role in both domestic drinking water and the pretreatment of general industrial water.

l Automatic Backwash Function: The automatic backwash mechanism is a highlight. The equipment can automatically trigger backwash operations according to the preset conditions without the need for manual monitoring and manual cleaning at all times. This not only saves labor costs but also ensures that the filter bed is always in a good working state, extends the service life of the filter materials, guarantees the long-term stable filtration effect, and reduces the problem of the decline in filtration efficiency caused by the accumulation of impurities.

l Stable and Reliable Operation: Its structural design is scientific and reasonable, and each component is of reliable quality. Moreover, in the face of different water flow pressures and changes in water quality and other working conditions, it can operate stably and is not prone to malfunctions. It continuously provides a stable and up-to-standard water quality guarantee for the water use system, reduces the maintenance cost and the impact on water use caused by equipment failures, and is suitable for the water treatment needs of long-term uninterrupted operation.

l Wide Range of Adaptability: Whether dealing with water from different sources and natures such as municipal water supply, industrial circulating water, domestic sewage, or groundwater, shallow sand filters can adapt by adjusting operating parameters and selecting filter materials. They can also be used in combination with other water treatment equipment and can find suitable application scenarios in different water treatment processes, with strong versatility.

l Simple and Easy Operation: The operation process of the equipment is relatively simple. Workers only need to master basic operations such as controlling the inlet and outlet of water and simply checking the equipment status. For the automated process of backwashing, they only need to ensure that the preset parameters are correct. There is no need for complex professional skills and frequent manual intervention. Ordinary personnel can master the operation method after simple training, facilitating its promotion and use in various places.

APPLICATION FIELDS AND INDUSTRIES

l Industrial Field: In industrial industries such as chemical, power, and steel, a large amount of industrial water containing impurities is generated. Shallow sand filters can filter the circulating cooling water to remove impurities such as suspended solids and rust in the water, prevent the cooling water pipelines from scaling and clogging, improve the cooling efficiency, and ensure the normal operation of production equipment. For the pretreatment of some process water, it can also effectively remove large-particle impurities, laying a foundation for subsequent fine treatment and ensuring the smooth progress of the production process.

l Municipal Water Supply Field: The source water for municipal water supply often contains impurities such as sediment, algae, and microorganisms. Shallow sand filters, as important equipment in the pretreatment or advanced treatment process, can further purify the water quality, improve the quality of the water supply, ensure the safety and hygiene of residents' water use, enable residents to use clearer and odorless drinking water, and also help to reduce the maintenance cost of the water supply pipeline caused by the deposition of impurities and extend its service life.

l Sewage Treatment Field: In the process of treating domestic sewage and industrial wastewater, shallow sand filters can first conduct preliminary filtration on the sewage to remove large-particle suspended solids, some colloids, etc., reducing the burden on subsequent treatment processes, improving the efficiency of the entire sewage treatment system, enabling the subsequent biochemical treatment, advanced treatment, and other processes of the sewage to proceed more smoothly, and finally achieving the goals of meeting the discharge standards or recycling the sewage, which has a great significance for the rational utilization of water resources and environmental protection.

l Agricultural Irrigation Field: If agricultural irrigation water contains too many impurities, it is easy to clog the irrigation nozzles, affect the irrigation effect, and even damage crops. Shallow sand filters can filter irrigation water sources such as surface water and groundwater, remove sediment, debris, etc., ensure the cleanliness of the irrigation water, enable the irrigation system to supply water to crops evenly and stably, help to improve the yield and quality of crops, and promote the sustainable development of agriculture.

SUMMARY

Shallow sand filters, with their unique structural design, efficient working principle, and many excellent performance characteristics, have shown strong application value in many fields such as industry, municipal, sewage treatment, and agricultural irrigation. They are like the capable assistants for efficient water purification, quietly contributing to ensuring the cleanliness and efficient utilization of water resources, helping to stabilize the development of various industries and improve people's living quality. With the continuous progress of science and technology, it is believed that shallow sand filters will continue to make breakthroughs in aspects such as improving filtration precision, deepening the degree of automation, and expanding applications, further meeting the increasingly diverse water treatment needs of society and becoming important supporting equipment for creating a high-quality water environment and facilitating the development of various industries.