How the Cofit AP series continuous screen changer works
Which are the operating principles of Cofit AP series screen changer? Particularly suitable for BOPP and BOPET film, Cofit AP manual, continuous, self-cleaning, and maintenance-free screen changer is a best-in-class performing, sturdy, and cost-effective solution.
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TOP QUALITY BOPP AND BOPET FILM
In a continuous plastic extrusion system, the introduction of a manual, continuous and self-cleaning screen charger with high filtration capacity offers plenty of benefits and ensures top end product quality.
In particular, plastic extrusion systems intended for the production of top-quality film (in particular, cast film, blown film, filaments, nonwoven, wire & cable, pipes, technical items, etc.) use virgin polymers such as BOPP, BOPET, PE, PP, ABS, PET, Nylon, PA, PS, etc., with the addition of a small percentage of recycled materials every now and then.
MINIMIZED MAINTENANCE COSTS
In such a scenario, a manual, continuous and self-cleaning screen changer offering high filtration capacity represents the best-in-class solution for the production of high-quality film. Besides the above characteristics, a screen changer should feature minimized maintenance costs.
The AP series by Cofit International offers all the above benefits – manual, continuous and self-cleaning, it requires a minimum investment and involves minimized maintenance costs. Having a closer look at manual, continuous and self-cleaning AP screen changer and its mechanical and dynamic features, it becomes clear that Cofit AP screen changer operation is amazingly simple, its structure is sturdy, and its maintenance costs are almost zeroed.
AP SERIES MANUAL, CONTINUOUS AND SELF-CLEANING SCREEN CHANGER – OPERATING PRINCIPLES
Cofit AP manual, continuous and self-cleaning screen changer can filter polymers and bring plastic material to a very high-level purity to offer unrivalled end products. As a standard, inlet plastic material flows through 2 separated channels. In each channel, flow is intercepted by a screening element that retains impurities and let the material flow through. The screen changer is equipped with 4 valves intended for managing screener self-cleaning and replacement processes.
Cofit AP manual continuous screen changer allows one of the 2 flows to be interrupted to carry out screener self-cleaning or replacement operations, with no production interruption, thus keeping material flow uninterruptedly.
MANUAL, CONTINUOUS AND SELF-CLEANING SCREEN CHANGER – SCREENING ELEMENTS
Besides its main frame and melt flow channels, AP main components are its 2 screening elements including a breaker, a screener, and a screen support. Each screening element is located in one of the two channels.
Each screening element is made of a breaker, a screener, a screen support
AP SERIES CONTINUOUS SCREEN CHANGER – SCREENER REPLACEMENT
In a Cofit AP continuous screen changer, screen access and removal require the melt flow to be interrupted in just one channel, thus letting the other channel operating. Screeners can be removed and replaced simply and quickly.
From the video, it can be understood the operation of each screening element and how simple and easy it is to access, remove and replace screeners in Cofit AP series screen changers.
In Cofit AP series, screeners can be removed and replaced simply and quickly.
VALVES AND SEALINGS
Besides screeners, flow adjustment valves are key components in a Cofit AP manual continuous screen changer. The melt flow through each channel is controlled by two valves – the inlet one and the outlet one. Each valve can be opened, closed, or positioned at 45°, thus enabling the melt to flow through the channel or not and making self-cleaning procedure start.
As melt pressure can be extremely high, gaskets are arranged on valve upper part to prevent any leakages. These rings perfectly seal the melt flow both during standard flow and at valve opening and closing stages.
In each valve gaskets are arranged to prevent any leakeage
As you can see in the video, valve opening and closing are remarkably simple and effective – by a simple lever, the valve is physically rotated to interrupt/enable the melt flow.
AP SERIES CONTINUOUS SCREEN CHANGER – HOW IT WORKS
The melt inlet channel immediately splits, thus creating two separate flows. Filtration processes take place fully independently through the two channels, in which the independent screening elements operate.
In a countinuous screenchanger, the melt inlet channel immediately splits, thus creating two separate flows After filtration, the 2 flows are joined again to outflow from the screen changer
2 INDEPENDENT SCREENING ELEMENTS
The presence of 2 independent screening elements offers an uninterrupted filtering process – the melt flows through one channel at least, while the other channel is stopped to enable screener self-cleaning or replacement according to user’s needs.
After filtration, the 2 flows are joined again to outflow from the screen changer at the required purity level, ready for the production of film or other products.
In a Cofit AP screen changer, impurities retained by the screener are removed by a self-cleaning procedure enabled by melt counterpressure. Any impurities retained by screeners are eliminated through purging channels and holes.
In a countinuous, self-cleaning screenchanger, impurities retained by screeners are eliminated through purging channels and holes.
Cofit AP continuous screen changer requires rare and minimized maintenance interventions. In a Cofit AP screen changer, the screener could operate for several weeks without any intervention, depending on melt contamination level. After several weeks of uninterrupted operation, the breaker replacement takes just a few seconds, once interrupted one of the melt flows and with no need for the filtering process to be stopped.
A HIGH PERFORMING AND HIGH FILTERING SCREEN CHANGER
Cofit AP screen changer structure is simple and extremely sturdy; in particular, AP does not need any motor or hydraulic or pneumatic components – this means that operation interruptions for maintenance interventions are minimized and life cycle is extended. Besides, AP combines an unrivalled filtering strength and capacity as it can operate at over-500-bar pressure and it offers filtering levels exceeding 10 microns. Have a look at AP technical data sheet.
Cofit deals with research, designing, manufacturing and distribution of continuous screen changers, either automatic or manual, intended for any sector and process material, in particular BOPP and BOPET film. Contact us to see how a manual and continuous screen changer can optimize your plastic extrusion process.