disc filter

Disc filter is a new type of high-efficiency filter, which has the advantages of fast filtration speed, time-saving and water-saving backwashing, small footprint, simple maintenance, and long service life. It can replace most traditional filters and is widely used in various occasions such as ultrafiltration, reverse osmosis, ion exchange, pre filtration, groundwater removal, turbidity removal, circulating cooling water system, urban sewage reuse system, etc.

One Disc filter structure

The disc filter consists of a controller, filter unit, filter housing, diaphragm valve, solenoid valve, flow meter, differential pressure signal meter, etc. The filtering units can be combined in parallel to meet different flow requirements. The filtering unit consists of a filter head and a filter disc. The filter head is generally made of reinforced polyamide plastic, and the filter disc material is polypropylene plastic. The filter housing is made of various materials such as carbon steel and stainless steel.

II Characteristics of disc filters

1. Precise filtration:

Filter discs can be selected according to different water requirements, with an accuracy range of 20 μ m-200 μ m.

2. Efficient backwashing:

The backwash time is only 5-20 seconds, which saves time and water, and the backwash is extremely thorough.

3. Fully automatic operation, continuous water production:

It can be equipped with a fully automatic controller to automatically control the backwashing process of each filtering unit alternately through time, flow rate, and pressure difference signals, ensuring continuous water supply.

4. Long service life:

The filtering unit is made of high-tech plastic, which is corrosion-resistant and wear-resistant

5. Small footprint:

Compared with similar filters, disc filters require less space to achieve the same filtration flow rate and accuracy

6. Fast filtration rate:

Suitable for high flow filtering

III Principle of disc filter filtration:

1. Working status:

The filtering unit of the disc filter has a set of filter discs with grooved edges, which are compressed by springs at the top. During filtration, sewage enters from the outside of the filter disc, and the intersection formed by the edges of adjacent filter discs intercepts solid substances in the water, achieving the filtering effect. At the same time, due to the fact that the dirt is not only stored between the filter disk and the filter head, but also inside the filter disk group, it has a deep coagulation effect, greatly improving the filtration effect.

2. Backwash status:

Disc filters can achieve automatic backwashing control in three ways: time, flow rate, and pressure difference signals. When one or more of these signals simultaneously meet the backwashing requirements, a signal will be sent to the controller, which will then control the backwashing components to complete the backwashing process. During backwashing, each filtering unit is alternated to ensure continuous water supply. The controller first controls the inlet and outlet valves of a filtering unit to change the direction of water flow, and then releases the top spring of the filtering disc. The nozzle located in the center of the disc group sprays along the tangent line, causing the disc to rotate and the dirt on the disc and inside the filtering head to be flushed out. Then control the inlet and outlet valves to restore this filtering unit to its normal working state, and proceed to backwash another filtering unit. Because the backwash time is very short, usually up to 15 seconds, and the filtration units alternate, generally disc filters do not require one in use and one backup.

Composed of parallel combination of filtering units, the filtering unit is mainly composed of a set of annular reinforced plastic filter discs with grooves or edges. During filtration, sewage enters from the outside, and the rim formed by the edges of the grooves on adjacent filter discs intercepts solid substances in the water; During backwashing, water flows from the inside of the annular filter disc to the outside, washing away the dirt trapped on the filter disc and discharging it through the drain outlet.

The discs are tightly compacted and stacked together within the unit, and the grooves in the middle of the upper and lower layers of discs serve to filter and intercept them.

Raw water flows from the outside to the inside when passing through the filtration unit, and impurities larger than the groove will be intercepted outside.

The core component of a disc filter is a stacked plastic filter disc, which has specially designed grooves or edges. The grooves or edges on adjacent filter discs form a channel of a certain size, and suspended particles with a particle size larger than the channel size are intercepted to achieve the filtering effect. This product can largely replace traditional mechanical filtration devices such as sand filters, with superior performance and much lower water and electricity consumption than other products.

The disc filter is designed with different structured edges on both sides of the filter disc, which are stacked together to form a blocking section. The curved edges mainly serve to intercept and store suspended solids. The slightly larger open design on the outer side can ensure that the filter disc does not need to be loosened during backwashing, and can achieve a thorough backwashing effect even at low water pressure; The circular edge determines the filtration accuracy, forming the water channel, and the filter disc can provide a filtration accuracy of up to 5 μ.

When the raw water enters the middle of the two layers of filter discs, it first flows along the curved edges into the disc, but upon careful observation, it cannot directly enter. At this point, the annular edge plays a filtering and intercepting role. Impurities smaller than the groove size of the annular edge can enter the curved edge connected to the inside along the annular edge, and larger impurities are intercepted.

The unique structure of the filter disc also makes the backwashing process of flushing out dirt simpler and easier, without the need for complex mechanisms such as motors and drivers. A simple water flow is sufficient to flush dirt out of the filter element. This excellent performance reduces the backwash time of the filter; Meanwhile, due to the fact that pollutants are not only stored between the filter disk group and the outer shell, but also more can be stored inside the filter disk group, the filter can accommodate more pollutants.