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Macro- and microfiltration of small samples
DUCTNEWS Continuouslarge-areafilter The large-area filter type DSF from Gneuss operates continuously and holds eight filter disc packs, each of which consists of 6- 10 individual discs. The disc packs are mounted in a rotating disc. Two filter packs are always in the melt stream and therefore actively in operation. Filter changes are carried out by a pressure-dependent control system. A continuous filtration process is ensured, since the surface area in operation is not reduced during the change. A continuous and controlled filtration process takes place compared to
the commonly used candle filters. The technical design ensures a melt flow without dead spots and guarantees that, with careful cleaning, no degraded material can be introduced into the melt stream. The filter disc packs are cartridges, and are therefore simple to replace. Applications are where extremely large surface areas are necessary, such as for example in the tibre industry or in the manufacture of raw materials. Gneuss Kunststoflechnik GrnbH, MGnichhusen 42, Postfach 101351, D-4970 Bad Oeynhausen 2, Germany. Tel: +49 5731 53070, Fax: + 49 5731 51928.
Backflushscreen changerfor continuousfiltration The Kreyenborg Bacldlush Screen Changer will ensure 100% continuous production, and will be a good investment for applications requiring a long filter life such aa in recycling. The distinguishing feature of these units compared to other backflush filter systems, is that while in the operating position, no plastic melt remains in the plastic channel (which would otherwise degrade there). Furthermore, no melt remains behind the screen, which would otherwise, after a relatively long time of thermal load, find its way into the product. The function of this reliable backtlush screen changer is baaed on the two-bolts principle. The melt flow is divided into two streams inside the screen changer housing, and continuous filtration of the melt is thereby ensured. When the melt pressure in front of the screens reaches a certain level as a result of increasing dirt accumulations in the screens, the screen bolts move automatically to the back6ush position, one after the other. While one of the screen bearer bolts is in the 10
backilush position, a small amount of material coming from the other screen bolt is directed from the rear side through the breaker plate and the contaminated screens. The dirt particles becoming loose during this procedure are conveyed outwards through the backflush port. During the whole procedure, production continues without disruption. Once the backflushing action has been finished, the screen bolt moves automatically back to the operating position. This is performed by a computer program control system developed specially by Kreyenborg for this backflush screen changer. In the conversion mode this control system ensures simple operation and correct working of the equipment. As a result of the automatic backflushing, the life of the screens is claimed to be lo- 100 times longer than with conventional screen changers, depending on the contamination and viscosity of the product. Joachim Kreyenboq & Co GrnbH, Postfach 15 01 65, Coermtihle, D-4400 Mtinste-r-Kinderhaus, Germany, Tel: +49 251 214050, Fax + 49 251214 0521.
Macro-and microfiltrationof small samples The Polydisc HD from Whatman Scientific is highly suitable for retaining particles in the 1- 10 pm size range from smaller sample volumes. The 50 mm polypropylene disposable device has been introduced to complement the limited choice of membrane products otherwise available for these applications. Polydisc HD is made entirely of polypropylene, including its monofilament anisotropic filtration medium. The use of monoiilament medium gives high loading capacity with good flow rates, while the 100% polypropylene construction ensures broad chemical compatibility and purity of the filtrate. An important feature is the stepped hose
barb inlet, which facilitates easy connection to 6- 10 mm diameter tubing for inline filtration, but it will also fit on the end of a syringe, for efficient filtration of smaller-size samples. The typical flow rate for the 5 pm pore-size Polydisc HD (1.5 l/min at 1 bar) makes it an appropriate choice for applications such as filtering ground water, biological solutions, beverages and solvents. For scale-up use at 1 bar the comparable 5 pm pore-sized Polycap 75 HD capsule device could be used, offering a flow rate of 13.8 l/min. whatmanScientQicLtd, whatman Howe, St Leonard-s Road, 20/&O Ma&tone, Kent ME16 OLS, UK. Tel: +44 622 676670, Fox: +44 622 677011.
Fib-flow dynamicstrainer/filtersystem Parmatic Esplen has developed the Filta-flow system to overcome many industrial filtration problems. It is a self-wiping system capable of high throughput, even for high-viscosity fluids and high-solids suspensions. The system has been used in the paint industry, where it has been successfully employed filtering zinc-rich epoxy primers (specific gravity 1.8), an application which had previously caused problems. Following the in-
troduction of Filta-flow, downtime was substantially reduced, with no deterioration in product quality. Flow rates and filter membrane rating vary depending on the application. A typical high-viscosity/ high-specific-gravity application would be 1200 kg/hr at 200 pm. Parmatic Esplen Ltd, Second Avenue, Flixbonnqh Industrial Estate, Scunthxnve. Humberside DN15 &SD. UK Tek % 44 724 281202, ~+Ix: + 44 724 858365.
Fine hole sheet for filtration Conidur Fine Hole Perforated Sheets are designed for use as filter plates, mill screens, centrifuge linings, conveyor distributor plates and silo drainage screens. They are manufactured with fine, conical profile perforations angled in the flow direction, to combine high screening capacity, minimised flow resistance and reduced clogging. The sheets. marketed in the UK by Pm&ok (Meshes & Perforations), come in a wide choice of lengths and widths and a variety of acid-, January/February
heat-, abrasion- and corrosion-resistant materials, including chrome-nickel-steel, Hastalloy, monel, copper, brass, aluminium, silver, titanium and tantalum. Surface treatment options include rolled smooth, polished, surface hardened, mud blasted and electrolytically deburred and polished. Polishing further reduces the risk of clogging and damage to delicate media. Plastok (Meshes & Petforations) Ltd, 77 Ma&et Street, Birkenhead L416AN, UK Tek + 44 516474570, Fax: + 44 51 647 3641. 1993
Flitration &I Separation
the commonly used candle filters. The technical design ensures a melt flow without dead spots and guarantees that, with careful cleaning, no degraded material can be introduced into the melt stream. The filter disc packs are cartridges, and are therefore simple to replace. Applications are where extremely large surface areas are necessary, such as for example in the tibre industry or in the manufacture of raw materials. Gneuss Kunststoflechnik GrnbH, MGnichhusen 42, Postfach 101351, D-4970 Bad Oeynhausen 2, Germany. Tel: +49 5731 53070, Fax: + 49 5731 51928.
Backflushscreen changerfor continuousfiltration The Kreyenborg Bacldlush Screen Changer will ensure 100% continuous production, and will be a good investment for applications requiring a long filter life such aa in recycling. The distinguishing feature of these units compared to other backflush filter systems, is that while in the operating position, no plastic melt remains in the plastic channel (which would otherwise degrade there). Furthermore, no melt remains behind the screen, which would otherwise, after a relatively long time of thermal load, find its way into the product. The function of this reliable backtlush screen changer is baaed on the two-bolts principle. The melt flow is divided into two streams inside the screen changer housing, and continuous filtration of the melt is thereby ensured. When the melt pressure in front of the screens reaches a certain level as a result of increasing dirt accumulations in the screens, the screen bolts move automatically to the back6ush position, one after the other. While one of the screen bearer bolts is in the 10
backilush position, a small amount of material coming from the other screen bolt is directed from the rear side through the breaker plate and the contaminated screens. The dirt particles becoming loose during this procedure are conveyed outwards through the backflush port. During the whole procedure, production continues without disruption. Once the backflushing action has been finished, the screen bolt moves automatically back to the operating position. This is performed by a computer program control system developed specially by Kreyenborg for this backflush screen changer. In the conversion mode this control system ensures simple operation and correct working of the equipment. As a result of the automatic backflushing, the life of the screens is claimed to be lo- 100 times longer than with conventional screen changers, depending on the contamination and viscosity of the product. Joachim Kreyenboq & Co GrnbH, Postfach 15 01 65, Coermtihle, D-4400 Mtinste-r-Kinderhaus, Germany, Tel: +49 251 214050, Fax + 49 251214 0521.
Macro-and microfiltrationof small samples The Polydisc HD from Whatman Scientific is highly suitable for retaining particles in the 1- 10 pm size range from smaller sample volumes. The 50 mm polypropylene disposable device has been introduced to complement the limited choice of membrane products otherwise available for these applications. Polydisc HD is made entirely of polypropylene, including its monofilament anisotropic filtration medium. The use of monoiilament medium gives high loading capacity with good flow rates, while the 100% polypropylene construction ensures broad chemical compatibility and purity of the filtrate. An important feature is the stepped hose
barb inlet, which facilitates easy connection to 6- 10 mm diameter tubing for inline filtration, but it will also fit on the end of a syringe, for efficient filtration of smaller-size samples. The typical flow rate for the 5 pm pore-size Polydisc HD (1.5 l/min at 1 bar) makes it an appropriate choice for applications such as filtering ground water, biological solutions, beverages and solvents. For scale-up use at 1 bar the comparable 5 pm pore-sized Polycap 75 HD capsule device could be used, offering a flow rate of 13.8 l/min. whatmanScientQicLtd, whatman Howe, St Leonard-s Road, 20/&O Ma&tone, Kent ME16 OLS, UK. Tel: +44 622 676670, Fox: +44 622 677011.
Fib-flow dynamicstrainer/filtersystem Parmatic Esplen has developed the Filta-flow system to overcome many industrial filtration problems. It is a self-wiping system capable of high throughput, even for high-viscosity fluids and high-solids suspensions. The system has been used in the paint industry, where it has been successfully employed filtering zinc-rich epoxy primers (specific gravity 1.8), an application which had previously caused problems. Following the in-
troduction of Filta-flow, downtime was substantially reduced, with no deterioration in product quality. Flow rates and filter membrane rating vary depending on the application. A typical high-viscosity/ high-specific-gravity application would be 1200 kg/hr at 200 pm. Parmatic Esplen Ltd, Second Avenue, Flixbonnqh Industrial Estate, Scunthxnve. Humberside DN15 &SD. UK Tek % 44 724 281202, ~+Ix: + 44 724 858365.
Fine hole sheet for filtration Conidur Fine Hole Perforated Sheets are designed for use as filter plates, mill screens, centrifuge linings, conveyor distributor plates and silo drainage screens. They are manufactured with fine, conical profile perforations angled in the flow direction, to combine high screening capacity, minimised flow resistance and reduced clogging. The sheets. marketed in the UK by Pm&ok (Meshes & Perforations), come in a wide choice of lengths and widths and a variety of acid-, January/February
heat-, abrasion- and corrosion-resistant materials, including chrome-nickel-steel, Hastalloy, monel, copper, brass, aluminium, silver, titanium and tantalum. Surface treatment options include rolled smooth, polished, surface hardened, mud blasted and electrolytically deburred and polished. Polishing further reduces the risk of clogging and damage to delicate media. Plastok (Meshes & Petforations) Ltd, 77 Ma&et Street, Birkenhead L416AN, UK Tek + 44 516474570, Fax: + 44 51 647 3641. 1993
Flitration &I Separation