This disclosure relates to filtration screens for use in a backwashable granular media bed filtration system. Drop-in retrofit kits for a backwashable granular media bed filtration system comprising one or more filtrations screens are provided herein. Such screens and kits can comprise a media support screen, a backwash filter screen, or a combination thereof. The kit can further comprise an agitator element comprising an impeller having vanes in which the impeller vane surfaces are coated with an abrasion resistant material. Associated filtration systems and processes are also described herein.

The invention relates to an apparatus for the filtration of aqueous liquid that is capable of effectively removing suspended particles from aqueous liquid during a prolonged period of time without clogging of the particulate filter media and associated pressure build-up. This filtration apparatus comprises: ⋅a filtration chamber comprising an inlet opening that is located near the bottom of the filtration chamber, and an outlet opening that is located near the top of the filtration chamber; ⋅a screen covering the outlet opening of the filtration chamber; ⋅a first dosing unit that is located upstream of the filtration chamber adapted to release water-soluble components into the stream of aqueous liquid that flows from the inlet to the filtration chamber; ⋅a particulate filter media that partially fills the interior of the filtration chamber; ⋅a flow regulator that regulates the flow rate of aqueous liquid through the filtration chamber and that can operate in a high flow rate mode or a reduced flow rate mode; ⋅a timer that controls the flow regulator; wherein the timer is programmed to alternatingly switch the flow regulator from the high flow rate mode to the reduced flow rate mode.

The invention relates to a filter system for treating contaminated liquids, having a filter container (11) that is equipped with a filter bed (12) comprising filter granulate as the filter material, a retaining element (13) being provided for the filter material via the filter bed. In order to allow the retaining element (13) to be lightly cleaned after backwashing and prevent filter material from being lost during the backwash, the retaining element (13) has a substantially vertically arranged filter screen (14) which is arranged at least partly outside of the filter container (11) and encloses a cavity, and liquid can flow outwards from the inside during the backwash. The cavity is open at the bottom such that retained filter material falls back into the filter bed (12). Because the flow within the filter bed (14) is oriented downwards, at least one turbine blade (18) can be provided, and a channel (16) can provided from the filter container (11) to the head space (17) of the filter screen (14). Preferably, a dissolver disc or a stirring mechanism (15) is provided in order to improve the flow formation. Alternatively, instead of a turbine blade, a funnel (15′) can be arranged on the lower end of the filter bed (14).

The invention relates to an apparatus for the filtration of aqueous liquid that is capable of effectively removing suspended particles from aqueous liquid during a prolonged period of time without clogging of the particulate filter media and associated pressure build-up. This filtration apparatus comprises: a filtration chamber comprising an inlet opening that is located near the bottom of the filtration chamber, and an outlet opening that is located near the top of the filtration chamber; a screen covering the outlet opening of the filtration chamber; a first dosing unit that is located upstream of the filtration chamber adapted to release water-soluble components into the stream of aqueous liquid that flows from the inlet to the filtration chamber; a particulate filter media that partially fills the interior of the filtration chamber; a flow regulator that regulates the flow rate of aqueous liquid through the filtration chamber and that can operate in a high flow rate mode or a reduced flow rate mode; a timer that controls the flow regulator; wherein the timer is programmed to alternatingly switch the flow regulator from the high flow rate mode to the reduced flow rate mode.

A filter structure has a main body and a stirring member. The main body has a hollow containment space filled with a filtering material. A filtering mesh is disposed at a bottom side of the containment space. A first purifying opening is disposed at a top end of the main body. A second purifying opening is disposed at a lower sidewall position of the main body above the filtering mesh. A first cleaning opening and a second cleaning opening are disposed on the main body and respectively coupled to a first and second inner pipe. An outlet is disposed at a bottom of the main body. The stirring member has an upper cover corresponding to the first purifying opening of the main body. The upper cover further has a driving arm and a connecting rod, and the connecting rod has a plurality of stirring rods.

This disclosure relates to filtration screens for use in a backwashable granular media bed filtration system. Drop-in retrofit kits for a backwashable granular media bed filtration system comprising one or more filtrations screens are provided herein. Such screens and kits can comprise a media support screen, a backwash filter screen, or a combination thereof. The kit can further comprise an agitator element comprising an impeller having vanes in which the impeller vane surfaces are coated with an abrasion resistant material. Associated filtration systems and processes are also described herein.

A filter structure has a main body and a stirring member. The main body has a hollow containment space filled with a filtering material. A filtering mesh is disposed at a bottom side of the containment space. A first purifying opening is disposed at a top end of the main body. A second purifying opening is disposed at a lower sidewall position of the main body above the filtering mesh. A first cleaning opening and a second cleaning opening are disposed on the main body and respectively coupled to a first and second inner pipe. An outlet is disposed at a bottom of the main body. The stirring member has an upper cover corresponding to the first purifying opening of the main body. The upper cover further has a driving arm and a connecting rod, and the connecting rod has a plurality of stirring rods.