INTRODUCTION

Backwash filters are key equipment widely used in various water treatment scenarios, with a reasonable structural design and practical functions. They mainly consist of a filter tank, a filter screen, a backwash device, a sewage outlet, and a control system.

The filter tank provides a stable outer shell support for the entire equipment, ensuring the stable operation of internal components. The filter screen is the core component, usually made of corrosion-resistant and high-strength materials such as stainless steel. Its pore size can be customized according to different filtration requirements and can accurately intercept suspended solids, particles, impurities, and other substances in water, ranging from large sediment particles to tiny colloids. The backwash device is like a "cleaning assistant" responsible for performing a reverse wash on the filter screen at the appropriate time to remove the dirt attached to it and restore the filtration performance of the filter screen. The sewage outlet is used to discharge the sewage carrying impurities during the backwash process.

The control system plays the role of an "intelligent brain". It can automatically determine when to start the backwash program according to preset parameters, such as changes in the pressure difference across the filter screen and the filtration time, and precisely control the entire backwash process to achieve automated operation without the need for frequent manual intervention. This equipment comes in a variety of specifications and can meet different needs for water treatment, from small-scale household water filtration to large-scale industrial production and municipal water supply. Its appearance design is compact, easy to install, and it operates stably and reliably, continuously and effectively purifying water quality.

WORKING PRINCIPLE

The working principle of backwash filters centers around two key links: filtration and backwash. When water containing impurities enters the filter tank, the water flow will pass through the filter screen. Since the filter screen has a specific pore size range, impurities with particle sizes larger than the pore size of the filter screen will be intercepted on the influent side of the filter screen, while water and substances with particle sizes smaller than the pore size of the filter screen can smoothly pass through the filter screen and flow out from the water outlet, thus completing the preliminary filtration of the raw water and obtaining relatively clean water.

As the filtration process continues, more and more impurities will be intercepted on the filter screen, resulting in a gradual increase in the pressure difference across the filter screen. When the pressure difference reaches the preset value of the control system or when the preset filtration time is reached, the control system will start the backwash device. At this time, the backwash device will change the direction of the water flow, causing the water to flow backward from the outlet side of the filter screen, forming a powerful impact force of the water flow to wash down the impurities attached to the filter screen. The sewage carrying these impurities will be discharged out of the equipment through the sewage outlet. After the backwash, the filtration performance of the filter screen is restored, and the equipment returns to the normal filtration state, repeating this cycle continuously to ensure a continuous and stable filtration effect.

MAIN PERFORMANCE AND CHARACTERISTICS

l High-Efficiency Filtration Capacity: Thanks to the high-precision filter screen, backwash filters have a remarkable effect on intercepting impurities in water. They can effectively remove common substances in water such as sediment, rust, algae, and suspended solids, significantly reducing the impurity content in water, improving the clarity and purity of water quality, and making it meet the requirements of various water use scenarios for water quality, whether it is domestic drinking water or industrial production water, providing a powerful guarantee for water quality.

l Automatic Backwash Function: Its automatic backwash mechanism is a highlight. There is no need for manual monitoring of the filter screen status and manual cleaning at all times. The equipment can automatically complete the backwash and sewage discharge operations according to the preset conditions, saving a lot of labor costs. At the same time, it also ensures that the filter screen is in a good working state for a long time, extends the service life of the filter screen and the entire equipment, and ensures a stable filtration effect.

l Stable Operation Characteristics: Equipped with a reliable control system and high-quality mechanical components, backwash filters can operate stably under different working conditions, such as different water flow speeds, pressures, and changes in water quality, and are not prone to malfunctions, effectively ensuring the continuity of water treatment work and continuously providing stable and up-to-standard water quality for the water use system.

l Wide Range of Adaptability: Whether dealing with municipal water supply, industrial circulating water, domestic sewage, or seawater desalination, and regardless of the source and nature of the water, backwash filters can play their role. By selecting appropriate filter screen pore sizes and adjusting corresponding operating parameters, they can adapt to a variety of complex water quality conditions and have strong versatility, showing their value in many fields.

l Energy Saving and Environmental Protection Advantages: During the backwash process, the equipment adopts a relatively energy-efficient backwash method. Compared with some traditional filtration equipment that requires a large amount of energy or resources for cleaning and maintenance, it can reduce energy consumption while ensuring a good filtration effect and avoid unnecessary waste of resources, which is in line with the current concept of green environmental protection and sustainable development and helps to reduce the overall cost of water treatment.

APPLICATION FIELDS AND INDUSTRIES

l Industrial Field: In industrial production such as the chemical, steel, and power industries, a large amount of industrial water containing impurities is generated. Backwash filters can filter the circulating cooling water to remove impurities 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 some process water with high water quality requirements, such as in the pre-treatment stage of ultrapure water preparation in the electronics industry, it can intercept tiny particles in water, laying a good foundation for subsequent fine treatment and ensuring the production of high-quality electronic products.

l Municipal Water Supply Field: In the municipal water supply system, the source water may contain impurities such as sediment, algae, and microorganisms. Backwash filters, as a part of 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 and extend its service life.

l Sewage Treatment Field: For the treatment of domestic sewage and industrial wastewater, backwash filters can first conduct preliminary filtration on the sewage to remove large suspended solids and the like, 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.

l Agricultural Irrigation Field: If agricultural irrigation water contains too many impurities, it may clog the irrigation nozzles, affect the irrigation effect, and even damage crops. Backwash filters can filter irrigation water sources such as surface water and groundwater, remove sediment, debris, and other substances, 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.

SUMMARY

Backwash filters, with their unique working principles and excellent performance characteristics, have shown strong application value in many fields such as industry, municipal, sewage treatment, and agricultural irrigation. They are like the efficient filtration "guardians" for protecting water quality, quietly contributing to ensuring the cleanliness and efficient utilization of water resources. With the continuous progress of science and technology, it is believed that backwash 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 an important supporting equipment for creating a high-quality water environment and facilitating the development of various industries.