Fiber disc filter

Fiber Rotary Filter

Filter disc:

It is composed of multiple fan-shaped filter plates, each filter disc is installed on a polygonal central drum, and each fan-shaped plate is wrapped with high-strength filter cloth. For example, some fiber rotary filter single-piece discs are composed of 6 easily detachable fan-shaped pieces, and the filter cloth is installed on the fan-shaped pieces, while some filter discs each have 6 independent fan-shaped pieces.

Center drum:

It is the mounting support component of the filter disc. For example, in some fiber rotary filters, each center drum device includes SS304 stainless steel center drum, drive gear, drive chain, frame and filter cloth assembly components, and each drum has an annular drainage seal at the water outlet.

Drive device:

It includes a drive motor, a drive shaft, a gear box, a drive gear, an SS304 stainless steel drive chain and an SS304 stainless steel chain cover. The driving motor is a flange-mounted asynchronous induction motor with a service factor of ≥1.5, a power supply of 380V, 3 phases, 50Hz, a power of 1.5kw, and an overload protection function. The equipment operating noise is less than ≤70dB, and a remote adjustable chain tensioning mechanism is also provided.

Backwash system:

Includes a backwash water pump, a backwash slag tank, and supporting pipes, nozzles, etc. The filtered clean water is pressurized by the backwash water pump, and the nozzle is atomized to rinse the surface of the filter membrane. The impurities on the water inlet side are flushed down and discharged into the backwash slag tank on the upper part of the central tube and discharged from the body. The backwash pump can be controlled in conjunction with the liquid level. When the filtration pressure difference or filtration cycle reaches the set value, it will automatically start to clean the filter cloth. When the water quality contains special substances, a special water heating device can be customized. The flow components, including the flow part of the backwash water pump, are all made of corrosion-resistant 304 stainless steel.

Fixed bracket and parts: The diaphragm is fixed on the central drum through the diaphragm. The diaphragm bracket is made of ABS material, and the strength meets the diaphragm support force. The diaphragm is installed in a slot type, which is easy to disassemble and assemble separately, and convenient for inspection and maintenance.

2. Working principle of fiber rotary filter

Filtration process:

There are many ways for raw water (sewage) to enter, such as sewage gravity flow into the filter tank. In some structures, the raw water enters the central drum from the central water inlet pipeline, and enters the filter disc fixed around the drum through the water distribution hole of the central drum. Filter cloth (such as filter cloth woven from stainless steel wire or polyester wire) is installed on both sides of the filter disc. After the raw water is filtered through the filter cloth, the clean water flows out of the filter cloth and is discharged from the filtered water outlet. During the filtration period, the filter turntable is in a static state. As the filtration proceeds, the impurities trapped on the inside of the filter cloth continue to increase, the filtration pressure difference increases accordingly, and the amount of water passing through the filter cloth decreases.

Backwashing process:

As the trapped substances on the filter cloth increase, the liquid level difference inside and outside the filter disc (or the change in the liquid level in the pool) reaches a certain height, and backwashing begins. For example, the water level in the pool is detected by the pressure monitoring device (or the change of the liquid level in the pool is monitored by the pressure sensor). When the backwash setting value (high water level) is reached, the PLC starts the back suction pump (or backwash system) to start the backwash process. During cleaning, the filter tank can filter continuously, and the filter turntable rotates at a certain speed (such as 1 turn/2 minutes). Two filter discs are a group. Through the automatic switching of the electric valve on the suction pump pipeline, the cleaning of each group is carried out alternately during a complete cleaning process of the fiber turntable filter, and the suction pump works continuously during this period. During backwashing, the backwash water pump extracts the clean water that passes through the filter cloth and sprays it on the outside of the filter cloth to wash away the trapped impurities on the inside of the filter cloth. After washing, the sewage falls into the liquid receiving tray and then discharged from the device. The backwash process is intermittent.

3. Operation status of fiber turntable filter

Static filtration state:

The sewage flows into the filter tank by gravity. The filter tank is equipped with a baffle energy dissipation facility (or water distribution weir). The whole process is a continuous process. In this process, raw water continuously enters the filter tank and is filtered through the filter cloth, and the filter disc is stationary, which is conducive to the deposition of sludge at the bottom of the pool.

Negative pressure backwashing state:

As the filtration proceeds, when the backwashing trigger condition is met (such as the liquid level difference reaches the set value or the liquid level in the pool reaches the cleaning set value), backwashing begins. During the backwashing process, the sludge particles accumulated on the filter cloth are removed by negative pressure suction (such as the suction pump negative pressure suction filter cloth surface) or water spray flushing (such as backwashing water pump extracting clean water flushing), and the filter disc rotates at a certain speed to ensure that the filter cloth in each part can be cleaned, and in this process, the suction pump (or backwashing pump) continues to work, and each filter disc is cleaned alternately in groups.

Mud discharge process:

There is a bucket-shaped pool bottom under the filter disc of the fiber disc filter, which is conducive to the collection of pool bottom sludge and discharges the sludge deposited on the pool bottom during the filtration process from the filter tank.

4. Characteristics of fiber disc filter

Structure and design:

The design is sturdy and compact, generally made of 304 stainless steel or 316L stainless steel, with a long service life. And the structural design is conducive to maintenance, such as the filter cloth is installed on the fan-shaped small piece for easy replacement, and the diaphragm is installed in a slot type for easy disassembly and assembly.

Occupancy and energy consumption:

It occupies a small area, 75% less than the sand filter tank, and has a small head loss. The head loss before and after the filter cloth does not exceed 300mm, and the total head loss is 800-1000mm, which greatly reduces energy consumption. It can realize unpowered filtration and low-energy backwashing (such as fully immersed models) or adopt different flushing and mud discharge and power methods (such as semi-immersed models).

Operation and operation:

Simple operation and maintenance, fully automatic operation, no special person is required for supervision, the automatic control system can realize manual/automatic conversion, remote monitoring and other functions, and can control the operation of the water pump through feedback such as liquid level detectors.

Economic cost:

The initial investment and operating costs are much lower than other processes. For example, compared with other treatment schemes (such as coagulation, sedimentation, filtration treatment + disinfection, etc.) in sewage deep treatment, the investment is relatively low, the sewage does not need to be lifted, and the operating cost is low.

5. Application scope of fiber rotary filter

Sewage deep treatment:

It is used in sewage treatment plants to make sewage meet the discharge standards. Combined with dosing and enhanced deepening stage reaction, it can remove P, chromaticity, etc. It can also be used for upgrading and transformation of existing sewage treatment plants, such as upgrading from Class B to Class A standard discharge, and it can also realize the reuse of reclaimed water. The treated reclaimed water can be used for steel mills, power plant circulating cooling water, urban miscellaneous water reuse, papermaking, printing and dyeing industrial water, aquaculture and other water treatment.

Surface water purification:

It can be used in conjunction with other technologies to purify surface water into cooling water, boiler water, etc.