summarize

In the general filtration device, as the filtration process continues, the solid phase impurities in the liquid are trapped on the surface of the filter element, causing the pressure drop to increase, the filtration resistance to increase, and the filtration efficiency to decrease. At this time, it is generally necessary to interrupt the filtration operation, replace the filter element or take out the cleaning, which is time-consuming and troublesome, affecting the processing efficiency. AF type automatic backwash filter solves this problem well, the filter has the advantages of continuous filtration, automatic backwash sewage, compact structure, stable and reliable operation, large processing capacity, low operating costs, long service life and so on. The cleaning and sewage discharge process of AF automatic filter is automatically carried out during the operation of the equipment, and at the same time, the filter operation can still be carried out without affecting the normal water supply. The filter is mainly used for coarse and fine filtration of auxiliary cooling water, industrial circulating water, fire water, washing liquid and other similar suspensions.

Machine structure and working principle

Machine structure

Driving device

The drive device is composed of a motor and a reducer, which drives the transmission shaft to rotate at a low speed, and has the characteristics of large torque and high reliability. If an unexpected blockage occurs and the torque exceeds the design value, the electrical protection system automatically stops and sends an alarm signal.

Filter element

The filter element is fixed on the intermediate disk and evenly distributed on the inner and outer two circles to ensure a large filtration area in the fixed housing volume. Each filter element (filter element) is cylindrical, the wedge-shaped corrosion resistant steel wire strip is welded with the upper and lower seal, the interval of each wire strip is evenly arranged according to the requirements of filtration accuracy, and a multi-channel ring hoop is welded in the length direction. The filter element not only has enough stiffness and strength to make deformation, but also can strictly ensure filtration accuracy.

Backwash device

The backwashing device is composed of a rotating arm and a sealing mechanism, connected to the drive shaft, is the only rotating part in the machine, low speed, smooth operation, and adopts a special mechanical seal structure design, with good sealing performance, wear automatic compensation function is strong, to ensure the smooth realization of backwashing and the normal and reliable operation of the machine.

Differential pressure controller

The double contact differential pressure controller produced by German technology uses bellows type sensors, which can be used for neutral gases such as air, gas, water vapor and water, oil, refrigerant liquid media. The controller's setting value is adjustable, the adjustment range is 0.02-1.6MPa, and the working pressure range is 0.05-2.5MPa.

Electric diaphragm valve

The sewage valve connected with the sewage pipe selects the electric lined rubber diaphragm valve produced by the British Sammders technology and key parts, which is especially suitable for the filter slag with large mud and sand content, and will not return the torque overload, jam and close loosely, and has the advantages of reliable use and long life.

Working principle

The filtration and backwashing driving force of the machine are provided by the original water pressure head or pump, the pressure of the filter chamber of the system is basically constant, the liquid flows from the inner chamber of the filter element to the outside, and the entrainment of solid impurities is intercepted on the inner surface of the filter medium, causing the pressure difference between the internal and external chambers to rise, and the filtration resistance to increase gradually. When the pressure difference of the internal and external cavity exceeds a certain set value of the differential pressure controller, the differential pressure controller sends a signal to control the motor to start, drive the backwashing arm to rotate, and open the flushing liquid outlet solenoid valve. When the backwashing arm is turned under a filter element, the backwashing pipeline is connected with the inner cavity of the filter element, and the difference between the clear phase pressure of the filtrate and the atmospheric pressure pushes the filtrate through the filter medium in the reverse direction, on the one hand, the filter medium is washed, and on the other hand, the residue is automatically discharged. The backwash arm rotates once, and each filter element is cleaned and regenerated once, and so on. Therefore, it avoids frequent replacement of filter media or manual cleaning of filter elements, improves production efficiency, and can save a lot of time, labor and financial resources. Through the selection of filter media can meet different accuracy requirements, generally up to 10m or even higher. The entire filtration and backwashing process is automatically controlled without manual participation. The backwashing action is controlled by the differential pressure signal generator (the differential pressure size reflects the degree of blockage of the filter element), and the backwashing time is adjusted by the time relay. In the cleaning process, the cleaning area accounts for a small part of the total filtration area, and the washing pressure difference is large, so that the amount of backwash liquid is small, the filtration process is continuous, the fluctuation is small, and the washing efficiency is high.

The only rotating part in the machine is the same as the backwash arm, which has low speed and stable operation, and has the function of automatic compensation for wear, good sealing performance and low maintenance cost.