What is the working principle of an activated carbon filter?

What is the working principle of an activated carbon filter?

During operation, the water to be filtered enters the activated carbon filter through the inlet nozzle and passes through the filter element. It then exits via the outlet and is routed through the process piping as required by the user, with particulate impurities in the water being trapped inside the filter. As this filtration cycle continues, more and more particles accumulate, causing the filtration rate to decrease. Simultaneously, an increasing volume of influent wastewater flows in, progressively narrowing the filter pores and creating a pressure differential between the inlet and outlet. When this pressure differential reaches a preset threshold, the differential pressure transmitter sends an electrical signal to the control system, which activates the drive motor. The drive mechanism moves the shaft, simultaneously opening the vent port. The filter consists of a housing, multiple filter elements, a backwash mechanism, and a differential pressure controller, among other components.

The internal partition within the housing divides the inner chamber into upper and lower sections. The upper chamber is equipped with multiple filters, providing ample filter space and significantly reducing the overall filter footprint. A backwash suction cup is installed in the lower section. During operation, the turbid liquid enters the filter through the inlet and flows downward, passing through the partition’s apertures into the filter’s inner chamber. Particles larger than the filter mesh openings are retained, while the clarified water passes through the mesh and returns to the upstream side before being discharged from the outlet. The filtration system employs high-strength wedge-shaped filters and utilizes differential-pressure control and timed-cycle automation to perform automatic filter cleaning.

Impurities accumulated inside the activated carbon filter adhere to the filter surface, causing the differential pressure across the inlet and outlet to rise to a set threshold, or triggering the system when the timer reaches its preset duration. At this point, the electrical control cabinet sends a signal to activate the backwash mechanism. If the backwash suction nozzle is properly aligned with the filter inlet, the vent valve will open, allowing the system to drain water. This creates a negative-pressure zone within the suction nozzle and the filter interior, where the pressure is lower than the external water pressure, thereby drawing a portion of the clean recirculating water from outside the filter into its interior. Impurity particles adsorbed on the inner wall of the filter are carried along with the water flow and discharged through the vent valve. The specially designed filter generates a spray effect inside, ensuring that all impurities are flushed away from the smooth inner surface. Once the differential pressure across the filter returns to normal or the timer expires, the entire process continues with continuous material flow, minimal consumption of backwash media, and seamless, automated operation.

Activated carbon filters are widely used in industries such as metallurgy, chemical processing, petroleum, papermaking, pharmaceuticals, food production, mining, power generation, and municipal water supply. They are employed for the filtration of industrial wastewater and recirculating water, the regeneration of emulsions, the filtration and treatment of waste oils, as well as in continuous casting water systems, blast furnace water systems, and high-pressure water descaling systems for hot rolling in the metallurgical sector. This is an advanced, highly efficient, and easy-to-operate fully automatic filtration system.

Water to be filtered enters the gas chamber through the inlet, and impurities in the water accumulate on the stainless steel filter element, creating a differential pressure. A differential-pressure switch monitors changes in the pressure difference between the inlet and outlet; when the differential pressure reaches the set value, the electric controller activates the hydraulic control valve and sends a signal to the drive motor.

After the equipment is installed, technicians perform commissioning and set the filtration duration and the backwash switching time. Once the water to be treated enters through the inlet, the filter begins normal operation. When the preset backwash interval is reached, the electrical control unit sends signals to the hydraulic control valve and the drive motor, triggering the following sequence of actions: the motor rotates the cleaning brush to flush the filter; the control valve opens; the control valve discharges the effluent; and the entire backwashing process is completed in a short period. The internal structure of the filter housing primarily comprises a coarse filter, a fine filter, an air inlet pipe, a stainless-steel cleaning brush or stainless-steel air inlet, sealing rings, an anti-corrosion coating, and a rotating shaft.