Gravity Strainer for Paper and Pulp Fibers
Swedish Quality Filters manufactured in Hovmantorp, Sweden
BSW™ Gravity Strainer is designed to strain large amounts of “white water”, water with large amounts of suspended solids. This unit is for application where the concentration and the flows are too high for a pressurised filter.
The filter is used on water streams with 20 up to about 600 mg/l (ppm) fibres. Smaller units are used for up to about 1000 ppm. Typical applications are the mill’s spray water supply, purification of sealing water from vacuum pumps, polishing of water from flocculation plants and cooling towers. The filter is also used for purification of intake water from lakes and rivers.
Easy to install, self contained modular unit
No trapping or driving solids through screen openings
Fibers are continuously removed by bottom up spray showers
Performance can be fine tuned for change in concentration or flow rate
Small floor space compared to a number of inline strainers
Easy visual performance check and infrequent maintenance
No long shutdown required for cleaning
BSW™ Gravity Strainer is available in six sizes, has a self cleaning systems that work under atmospheric conditions, removing suspended solids from relatively high flow water streams up to 11000 l/min. They are most commonly used in the pulp and paper industries to reduce the fibre concentration and to remove felt hairs and fibre bundles. Also to separate long fibres and process debris from recycled plant waters.
Lifts fibers/debris off of screen with continuous backwash cleaning
Minimizes potential for clogging and chance of fiber stapling over wire
Allows a larger mesh than equivalent “top-down” filter
No backwash cycle or bag changing
25 to 700 m3/h
0.08 to 0.3mm (80 to 300 micron)
DN100 to DN400
0.25 – 0.37 kW, depending on filter size
Stainless steel EN1.4301 / EN1.4404 / EN1.4436
BSW10, BSW14, BSW17, BSW22, BSW25, BSW30
The water is fed in tangentially between the outer and inner jackets of the filter vessel. The water flows up and over the edge of the internal vessel and down onto the strainer media. Unwanted solids/fibres are captured upon the strainer media, and clean water passes through the fine filter mesh, exiting at the bottom of the strainer vessel. Cleaning is achieved by spray cleaning the strainer media in a novel way, “bottom-up cleaning”. Two spray bars positioned below the strainer media, rotates in-line with the unique collection chambers located directly above the strainer media. These collection chambers catch the fibres/solids lifted by spray water from the screen surface, and feed them down towards the drain. Fibres are transported inside the collection chambers, not on the top of the strainer media.