Precoat filter assembly
AssigneePall Corporation
InventorsAshok K. Bhanot, John D. Miller
Life of this patent
Estimating the term…
Abstract
A precoat filter element for a precoat filter unit comprises a flow distributor and flow straightener. The flow distributor surrounds a filter septum and has openings through which liquid may flow. The proportion between the area of openings and the area of a wall of the flow distributor may vary along the length of the septum to distribute flow over the length of the filter septum in a predetermined manner. A flow straightener is provided at the base of the septum to reduce turbulence during precoat and filtration operations, and to reduce the occurrence of large flocs in precoat slurries during coating operations.
Claims24
A filter assembly for a precoat type backwashable filter unit with a filter element chamber for holding liquid at high pressure and having an interior wall, an upper end, and a liquid inlet comprising:
- a filter element including
- a central cylindrical support and drainage core with an upper end, a lower end, a central drainage space, and a perforate wall to allow filtrate to flow into the drainage space and thence to an end of the core,
- means for supporting a precoat including a septum surrounding and generally coaxial with said core, and
- a base cap disposed at a lower end of said drainage core below said septum;
- a stand-off tube extending downward from the base cap and passing through the lower end of said chamber to carry filtrate from the central drainage space;
- and
- a flow straightener for reducing turbulence, the flow straightener traversing a fluid flow path between said septum and said inlet and comprising a wire knit mesh wrapping around said stand-off tube.
A filter assembly for a precoat type filter unit with a filter element chamber for holding liquid at high pressure and having an interior wall, an upper end, a lower end, and a liquid inlet comprising:
- a filter element including
- a central cylindrical support and drainage core with an upper end, a lower end, a central drainage space, and a perforate wall to allow filtrate to flow into the drainage space and thence to an end of the core and
- means for supporting a precoat including a septum surrounding and generally coaxial with said core and
- a flow distributor with a wall surrounding and generally coaxial with said core and said septum, said wall having openings defining an open area through which liquid may flow, the local ratio of the open area to the total surface area of the wall varying along the length of the septum.
A filter assembly for a precoat type backwashable filter unit with a filter element chamber for holding liquid at high pressure and having an interior wall, an upper end, a lower end, and a liquid inlet comprising:
- a filter element including
- a central cylindrical support and drainage core with an upper end, a lower end, a central drainage space and a perforate wall to allow filtrate to flow into the drainage space and thence to an end of the core,
- means for supporting a precoat including a septum surrounding and generally coaxial with said core, and
- a base cap disposed at a lower end of said drainage core below said septum;
- a stand-off tube extending downward from the base cap and passing through the lower end of said chamber to carry filtrate from the central drainage space through the chamber wall;
- and
- a flow straightener for reducing turbulence, the flow straightener comprising wire mesh surrounding a portion of said septum adjacent said base cap.
A filter assembly for a precoat-type filter unit having a filter element chamber which holds pressurized liquid and which includes a liquid inlet, the filter assembly comprising:
- a filter element including
- means for supporting a precoat including a septum which has a drainage space into which filtrate flows and
- a base cap disposed at a lower end of said septum;
- a stand-off tube coupled to said drainage space of said septum and passing through the chamber to carry filtrate from said septum;
- and
- a flow straightener for reducing turbulence, said flow straightener disposed around said base cap and traversing a fluid flow path between said inlet and said septum.
A filter assembly for a precoat-type filter unit having a filter element chamber which holds pressurized liquid and which includes a liquid inlet, said filter assembly comprising:
- a filter element including means for supporting a precoat, said precoat supporting means including a septum having a drainage space into which filtrate flows and
- a flow distributor having a wall surrounding and generally coaxial with said septum, said wall having openings defining on an open area through which liquid may flow and the local ratio of the open area to the total surface area of the wall varying along the length of the septum.
Dependencies are inferred from the claim text.