Hydraulically Controlled Self-cleaning Filter

Hydraulically Controlled Self-cleaning Filter
Hydraulically Controlled Self-cleaning Filter

In order to save water, households and industries often use recycled water. Industrial recycled water consumption accounts for more than 90% of the total recycled water consumption. However, when the industrial circulating water system changes, scaling, and corrosion will occur in the water quality. It is easy to cause problems such as blockage and corrosion of the circulating water pipeline, affecting the normal operation of the circulating water system.

In order to improve the utilization rate of water resources. The most direct and effective measure is to use circulating water filtration equipment – a self-cleaning filter. Through experiments and research, it was found that the rotation speed of the sewage discharge shaft of the self-cleaning filter is generally not high. In order to ensure the stable rotation speed of the sewage discharge shaft, it is mainly driven by a motor and needs to be connected to an external power supply.

It is significant if a fully automatic self-cleaning filter can be designed that does not require an external power supply and motor and can adjust the speed.

Working Principle

It is researched and designed based on the motor-driven self-cleaning filter and combined with actual needs.

The main advantages are that there is no need to install an external power supply for the motor, strong parts interchangeability, self-adjusting speed, self-filtering and self-cleaning, and filtering does not stop during cleaning, etc.

  • When sewage flows into the water inlet, it is filtered through the filter and out from the outlet. The filter is filtering normally.
  • With normal filtration, impurities adhere to the filter screen to form filter cakes. The filter cakes will form a great resistance to the filtration of sewage, causing the internal and external pressure difference to gradually increase.
  • When the pressure difference reaches a certain value, the filter cake will seriously affect the filtering effect. Therefore, the filter cake formed on the filter screen must be cleaned.
  • There are three main methods for cleaning filter cakes: suction, brushing or scraping, and backwashing.
  • When the drain valve is opened, the drain shaft is connected to the atmosphere. The pressure in the sewage discharge shaft and the sewage suction pipe drops sharply, thus generating a pressure difference between the sewage suction pipe opening and the filter screen, forming a huge suction force. The impurities on the filter surface are sucked into the suction pipe, flow into the discharge shaft, and discharged through the discharge valve.
  • When the pressure difference between the inside and outside of the filter is small, close the drain valve. The drain process is over and the filter is filtering normally.

Drive device

It mainly includes the filtering process, sewage suction process, and sewage discharge process. The driving device is the most critical component to complete the sewage suction and discharge processes. There are four main ways to drive the sewage discharge shaft to rotate.

  • The motor cooperates with the reducer to drive the sewage discharge shaft to rotate. Many companies use a motor with a reducer to drive the sewage discharge shaft to rotate.
  • Use the pressure difference between circulating water and air to form high-speed water flow. The driving wheel is pushed from the inside to the outside to drive the sewage shaft to rotate. The sewage valve is the bridge connecting the sewage shaft and the atmosphere.
  • Open the drain valve, the drain well is connected to the atmosphere, and the pressure in the pipe drops sharply. Therefore, a huge pressure difference is generated between the sewage suction port of the sewage suction pipe and the filter screen. Thereby, impurities on the surface of the filter are sucked into the sewage suction pipe. Under the action of pressure difference, sewage forms a high-speed water flow to drive the driving wheel to rotate.
  • Use high-speed water flow to impact the driving wheel to drive the sewage discharge shaft to rotate. Single a driving force structure, the drain valve is the bridge connecting the water wheel outlet and the atmosphere. The middle hole of the driving wheel and the drain shaft are mechanically connected, and the drain pipe is connected to the drain valve.
  • The high-speed water flow pushes the driving wheel to drive the sewage shaft to rotate. Under the action of the high-speed water flow in the water inlet and sewage outlet, the driving wheel drives the sewage shaft to rotate, thereby completing the sewage suction and discharge process.

Drive design

The speed can be adjusted. This is mainly achieved through the hydraulic speed control system composed of hydraulic components and drive wheels.
The throttle valve AT is connected in series between the water inlet and the drive wheel. It is used to control the flow entering the drive wheel and to adjust the rotation speed of the drive wheel.
The overflow valve is used to control the adjustment pressure PS. Through experimental testing, the driving wheel speed is adjustable. Filtration and cleaning operations are smooth, and the entire drive unit is easy to disassemble and assemble.

In Conclusion

Compared with traditional filters, the main advantage of this filter is that it does not require external energy. The system keeps flowing during continuous filtering and cleaning. The parts are highly interchangeable and easy to install, operate, and maintain. The structure is compact, the installation occupies a small area, and the sewage water consumption is small.

  • No need to connect to an external power supply, stable filtering, and easy to control. The hydraulic energy is converted into the mechanical energy of the driving wheel. The flow and pressure are controlled by the hydraulic circuit, and no external power supply is required.  Constant speed and stable filtration.
  • It can maintain continuous filtration, with no interruption of flow during cleaning and low water consumption for sewage discharge. Since the speed requirement for self-cleaning is not high and the water consumption is low, continuous filtration and flow can be maintained.
  • The parts are highly interchangeable, the filtration accuracy is easy to adjust, and it is easy to install, operate, and maintain. Except for special parts such as the outer cylinder, partition, and filter screen, all other parts are standard parts, which is convenient for replacing parts. For example: bolts, solenoid control valves sewage pipes, etc.
  • The sewage discharge shaft is used as the reference part during design. The structure of other parts is reasonably designed, and one-way installation is adopted for easy operation. Easy to maintain, different filter cartridges can be replaced. At the same time, the filtering accuracy of the filter can also be adjusted according to the actual needs of the enterprise.