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Accurate pollution monitoring
DDUCTNEWS JetAir serf-cleaning industrial filtration unit Air Plants Ltd has introduced the JetAir self-cleaning filtration unit for industrial dust control. This high-efficiency dust collector adds to APL's extensive range of dust control and disposal equipment. JetAir, with reverse pulse self-cleaning, offers high efficiency f i l t r a t i o n (in m o s t a p p l i c a t i o n s in e x c e s s of 99.99%), low running costs and a reduced maintenance requirement. It is suitable for application in most industries where there is a major dust control requirement. Dust-laden air enters via a high-level inlet, and flows into the 'dropout' section. Tl:e air flow is f o r c e d d o w n w a r d s towards the hopper section: this causes heavier particles to fall out of the air flow, to be collected in storage bins. The air then passes through the filter cartridges, where the
remaining dust is retained in the filter medium. Cleaned air can then either be recirculated or discharged to the atmosphere. To dislodge collected debris JetAir uses compressed air pulse cleaning. Regular reverse pulse cleanings helps to maintain a constant pressure loss across the filter cartridges, and keeps the air mass flow rates constant. A range of filter media is available, including fiame-retardant materials, antistatics, polypropylene, needlefelt, cellulose, glass fibre and polyester. Elements are pleated to maximise the filtration area; combined with the unit's advanced design, this results in a low filtration velocity. It also leads to a much lower pressure drop (between 375 and 750 N / m 2) than with a conventional bag filter. The low pressure drop • means less fan power is required, and lower running costs. Units are tailor-made to customer requirements. Typical sizes are from 800 to 100,000 1113// hr, with larger units possible.
688
Significant, practical refinem e n t s to C a r i e r Pollution Control's Rotoscreen slurry separator have resulted from design rationalisation leading to volume production of the high-throughput, low-mainten a n c e u n i t at t h e C a r i e r Group's Bralntree, U K factory. With all main components in 304-grade stainless-steel on a hot dip galvanised frame, the ruggedly reliable separator has been shown to operate successfully even in the harshest farm conditions, as well as at abattoirs and cattle markets. The fitting of a single 1.5 kW drive motor for d r u m and compression rollers has further reduced running c o s t s , at t h r o u g h p u t s of 8 - - 3 0 mS/hr on cattle slurry. More comprehensive guarding has been added, and the
availability of suitable sensors and controls allows completely automatic operation ff required. To avoid stones blocking or damaging the perforated drum, the twin compression rollers are on spring-loaded mounting bars, and are of a hard-faced but soft-cored composition to provide the necessary degree of resilience. There is also the patented scraper and roller-tensioning, the serf-draining facility with automatic washdown on completion of each cycle, and the Rotoscreen's ability to separate slurries of varying consistency without the need for dilution, mixing or adjustment of the unit. Carier Pollution Control Ltd, East Street, Braintree, Essex CM7 6JL, UK. Tel: +44 376 323349, fax: + 44 376 334540.
High-accuracy filter tube cutoffs
Air Plants Lid, 295 Aylestone Road, Leicester LE2 7PB, UK. Tel: + 44 (0) 533 833581.
Meltog has introduced a highaccuracy cutoff system to its STM200 s p i r a l filter t u b e making machine, to meet the r e q u i r e m e n t s of c o m p a n i e s working to Statistical Process Control standards. The unit incorporates a new scale and a dial setting guide which allow the operat o r to c h a n g e f i l t e r t u b e lengths quickly and precisely. Working to an accuracy of 0.01 ram, a fibre-optic scanner determines the precise c u t o f f point. As t h e t u b e emerges from the machine, a proximity switch reduces the production speed, allowing an accurate cutoff to be effected. The wholly self-contained
STM200 a u t o m a t i c a l l y produces completed filter tubes of any length from coils of plain or pre-perforated material. Tube diameters from 25 to 200 nun can be produced using a spiral lock seam. This allows lighter-gauge, lowercost material to achieve very high core strengths up to 30 bar, making these filtertubes suitable for heavy-duty applications. A wide range of materials can be converted into filter tubes, including steel, stainless-steel, tinplate and aluminium alloys.
change in performance. An important feature of glass microfibre filters is that they are extremely white, with a brightness of 96%. This is a major benefit when determining smoke stains by optical m e t h o d s . Air p o l l u t i o n is generally monitored by gravim e t r i c m e t h o d s b a s e d on collection of particles from a known volume of air drawn over the filter during a specified time period. Whatman's EPM 2000 has
been developed to meet the requirements of the U S Environmental Protection Agency method for high volume air sampling. It is treated to eliminate trace organics, and sheets are numbered to aid sample identification. U l t r a p u r e QM-A q u a r t z microfibre filters are recommended where acidic gases such as SO2 and NOz may be p r e s e n t . These b i n d e r - f r e e filters contain virtually no alkaline e a r t h metals, and are also useful where trace analysis of heavy metals such
as lead is to be carried out on the collected particulates. Glass microfibre extraction thimbles are frequently used in smoke stack monitoring because of their combination of filtration performance and high-temperature stability (up to 550°C). For critical requirements, tapered silica thimbles will cater for temperatures up to 1000°C.
Accurate air pollution monitoring Manufactured from 100% borosilicate glass without additives or binders, Whatman's glass microfibre filters are used where a high collection efficiency of fine particles is required. With low resistance to air flow and high retention efficiency, they effectively remove airborne particles as small as 0.I /~m in diameter. Furthermore, they can be used over a very wide temperature range, without embrittlement or significant
Slurry separator offers further refinements
Meltog Lid, Dark Lane, Gelderd
Road, Birstall, West Yorkshire WF17 9LW, UK Tel: + 44 924 422822,fax: + 44 924 422155.
W h a t m a n I n t e r n a t i o n a l Ltd, Whatman House, St Leonard's Road, 20/20 Maidstone, Kent ME16 OL8, UK Tel: +44 622 676670, fax: + 44 622 677011.
December 1993
Filtration & Separation
remaining dust is retained in the filter medium. Cleaned air can then either be recirculated or discharged to the atmosphere. To dislodge collected debris JetAir uses compressed air pulse cleaning. Regular reverse pulse cleanings helps to maintain a constant pressure loss across the filter cartridges, and keeps the air mass flow rates constant. A range of filter media is available, including fiame-retardant materials, antistatics, polypropylene, needlefelt, cellulose, glass fibre and polyester. Elements are pleated to maximise the filtration area; combined with the unit's advanced design, this results in a low filtration velocity. It also leads to a much lower pressure drop (between 375 and 750 N / m 2) than with a conventional bag filter. The low pressure drop • means less fan power is required, and lower running costs. Units are tailor-made to customer requirements. Typical sizes are from 800 to 100,000 1113// hr, with larger units possible.
688
Significant, practical refinem e n t s to C a r i e r Pollution Control's Rotoscreen slurry separator have resulted from design rationalisation leading to volume production of the high-throughput, low-mainten a n c e u n i t at t h e C a r i e r Group's Bralntree, U K factory. With all main components in 304-grade stainless-steel on a hot dip galvanised frame, the ruggedly reliable separator has been shown to operate successfully even in the harshest farm conditions, as well as at abattoirs and cattle markets. The fitting of a single 1.5 kW drive motor for d r u m and compression rollers has further reduced running c o s t s , at t h r o u g h p u t s of 8 - - 3 0 mS/hr on cattle slurry. More comprehensive guarding has been added, and the
availability of suitable sensors and controls allows completely automatic operation ff required. To avoid stones blocking or damaging the perforated drum, the twin compression rollers are on spring-loaded mounting bars, and are of a hard-faced but soft-cored composition to provide the necessary degree of resilience. There is also the patented scraper and roller-tensioning, the serf-draining facility with automatic washdown on completion of each cycle, and the Rotoscreen's ability to separate slurries of varying consistency without the need for dilution, mixing or adjustment of the unit. Carier Pollution Control Ltd, East Street, Braintree, Essex CM7 6JL, UK. Tel: +44 376 323349, fax: + 44 376 334540.
High-accuracy filter tube cutoffs
Air Plants Lid, 295 Aylestone Road, Leicester LE2 7PB, UK. Tel: + 44 (0) 533 833581.
Meltog has introduced a highaccuracy cutoff system to its STM200 s p i r a l filter t u b e making machine, to meet the r e q u i r e m e n t s of c o m p a n i e s working to Statistical Process Control standards. The unit incorporates a new scale and a dial setting guide which allow the operat o r to c h a n g e f i l t e r t u b e lengths quickly and precisely. Working to an accuracy of 0.01 ram, a fibre-optic scanner determines the precise c u t o f f point. As t h e t u b e emerges from the machine, a proximity switch reduces the production speed, allowing an accurate cutoff to be effected. The wholly self-contained
STM200 a u t o m a t i c a l l y produces completed filter tubes of any length from coils of plain or pre-perforated material. Tube diameters from 25 to 200 nun can be produced using a spiral lock seam. This allows lighter-gauge, lowercost material to achieve very high core strengths up to 30 bar, making these filtertubes suitable for heavy-duty applications. A wide range of materials can be converted into filter tubes, including steel, stainless-steel, tinplate and aluminium alloys.
change in performance. An important feature of glass microfibre filters is that they are extremely white, with a brightness of 96%. This is a major benefit when determining smoke stains by optical m e t h o d s . Air p o l l u t i o n is generally monitored by gravim e t r i c m e t h o d s b a s e d on collection of particles from a known volume of air drawn over the filter during a specified time period. Whatman's EPM 2000 has
been developed to meet the requirements of the U S Environmental Protection Agency method for high volume air sampling. It is treated to eliminate trace organics, and sheets are numbered to aid sample identification. U l t r a p u r e QM-A q u a r t z microfibre filters are recommended where acidic gases such as SO2 and NOz may be p r e s e n t . These b i n d e r - f r e e filters contain virtually no alkaline e a r t h metals, and are also useful where trace analysis of heavy metals such
as lead is to be carried out on the collected particulates. Glass microfibre extraction thimbles are frequently used in smoke stack monitoring because of their combination of filtration performance and high-temperature stability (up to 550°C). For critical requirements, tapered silica thimbles will cater for temperatures up to 1000°C.
Accurate air pollution monitoring Manufactured from 100% borosilicate glass without additives or binders, Whatman's glass microfibre filters are used where a high collection efficiency of fine particles is required. With low resistance to air flow and high retention efficiency, they effectively remove airborne particles as small as 0.I /~m in diameter. Furthermore, they can be used over a very wide temperature range, without embrittlement or significant
Slurry separator offers further refinements
Meltog Lid, Dark Lane, Gelderd
Road, Birstall, West Yorkshire WF17 9LW, UK Tel: + 44 924 422822,fax: + 44 924 422155.
W h a t m a n I n t e r n a t i o n a l Ltd, Whatman House, St Leonard's Road, 20/20 Maidstone, Kent ME16 OL8, UK Tel: +44 622 676670, fax: + 44 622 677011.
December 1993
Filtration & Separation