Automatic self-cleaning filter and the filter screen

Automatic self-cleaning filter is a kind of filter equipment with filter screen, backwashing mechanism, motor, drainage valve and electrical control system.

It can continuously filtrate the liquid, automatically clean the screen and discharge the impurities by the drain. It needs less shutdown time and maintenance because there is no chance to change the filter cartridge / bag like in other cartridge or bag filter. The filter screen has much longer service life than other consumable filter elements. Therefore the automatic screen filter can save total operation cost.

Automatic self-cleaning screen filter picture and drawing

Working principle of automatic self-cleaning filter:

Filtration cycle:

The fluid pass through the screen with the pressure driven by pump or pipeline. The impurities / particles are stopped and restrained on the surface of the screen. The clean filtrate flow to the downstream of the filter from the opening of the screen.

Cleaning cycle:

The cleaning cycle runs without the pause or stopping of the filtration cycle. When cleaning is starting, the drainage valve opens and the cleaning motor ( to drive a brush or suction scanner) starts. The impurities are removed then and flushed out by the drainage line.

There are two modes of automatic cleaning: time interval and differential pressure trigger.

Time interval motivated automatic cleaning:

The time interval before cleaning and the cleaning duration are set in the control system. For instance, we set the time interval as 10 minutes and the cleaning duration as 1 minutes. The filter will count the filtration time and trigger the cleaning for 1 minutes when the filtration time reaches 10 minutes. All the timer will return to zero after cleaning finished.

Differential pressure triggered automatic cleaning:

While the filtration cycle continues, the impurities accumulate on the screen and cause the rise of the differential pressure between the inlet and outlet of the filter and screen. When the differential pressure reaches the set value of the cleaning trigger, the filter will start the cleaning cycle to reach certain preset cleaning time or delta P value.

Safety backup:

The time interval and differential pressure mode can be the safety backup for each other. When differential pressure gauge and switch failed, the time interval mode will still clean the screen regularly. If the cleaning time interval is set too long and the differential pressure rises to trigger the cleaning cycle, the differential pressure mode will also clean the screen and protect the filter and components from overpressure.

Parameter table of automatic filter brush cleaning type.

Inlet and outlet connection can be customized.

Motor power is from 0.18 kw to 1.5 kw depending on the flow rate and pressure level.

Explosion-proof electrical system can be customized by request.

Filter screen of the automatic self-cleaning filter:

Wedge wire screen

Wedge wire v-slot filter screen with perforated metal tube reinforcement

Filter rating: 20 50 75 100 micron 125 150 200 micron 300 micron 400 micron 500 micron 1 mm 1.5 mm 2 mm

Other rating not listed can be customized.

Advantage of wedge wire screen is robust structure with high flow rate. The slot shape opening is not easy to clog and more efficient for long impurities like fiber and wire.

Sintered wire mesh screen

Sintered wire mesh with perforated metal filter screen

Filter rating: 5 micron 10 micron 20 micron 30 micron 50 micron 75 micron 100 micron 200 micron

Other rating not listed can be customized.

Sintered wire mesh screen is often made from sintered mesh with perforated metal. Sintered wire mesh screen has better filtration accuracy in finer filtration rating range. It can stop fine particles on the mesh screen surface and be cleaned easily.

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