JÖST GmbH + Co. KG

Based  of  the  increased  product  capacities  for  the  underwater pelletizing of plastic granulates JOEST extended the product range of the agglomerate screens.

Screen  decks  of  up  to  7,2  m²  in  compact  design  are  now  available.

The horizontally situated unbalance motors are infinitely adjustable and can therefore be ideally adapted to the product to be screened. The horizontal arrangement of the unbalance motors assures quiet start and stop action. Either  perforated  plates  or  wire  clothes  which  are  quickly  removable without tool, are available as screen deck. The vibratory cover made of aluminium is divided into several parts and fixed with quick release fasteners.

The SDE/SDZ Small Screen is a particularly compact version of a vibration screen equipped with the tried and tested JD Dosing Drive. As a linear feeder, they are used for sifting plastic granulates (strand granulates or underwater granulates) and can also be used in the foodstuffs industry as well as other sectors.

The clamped sifter trough and the simple design ensure swift and thorough cleaning when changing products. The thyristor controller is also ideal for adjusting the vibration width to suit the screened materials. The small screens are available in single- or double-decker versions and can be used for coarse materials, extra long materials or fine particle sifting. The small screens come standard in stainless steel 1.4301 with glass bead-blasted surfaces. The standard package includes a partial cover on the feed-end with an entry collar.

Other deliverable options include alternative structural materials, special surfaces, complete enclosures, exit collars and substructures (static, movable).

The unit can be equipped with a thyristor controller, which makes it ready to connect and conforms to CE requirements.

The spiral elevator combines the advantages of gentle product handling and vertical transport with vibration technology for bulk products suitable for feeding or in combination with thermal treatment. Plastic pellets with temperatures of 100 - 140 °C after the water quench could not be packed. An essential evaporation of surface moisture and cooling to the final temperature of 40 - 60 °C typically takes place during transport on the spiral elevator. The consolidated design allows heat exchange surfaces up to 40 m2. Aspiration or overflowing of the transport surface as well as housing made as static or co-vibrating cover is possible depending on the application. In case of operation with compounds with mineral fillers sensitive parts like product intake and discharge are equipped with wear protection.

The JOEST spiral elevator for thermal treatment is suitable for operation with different types of heat exchange media and temperatures. The design of the flights developed by JÖST enables an efficient heat exchange. A high level of mechanical stability is achieved by welded lateral curb execution. Additionally the typical reduction of material thickness in the bending radius of press formed flights is not applicable. Two unbalance motors with adjustable angle of attack on the drive saddle, displaceable vibrating stroke and operation with frequency converter provides an efficient

operation.

When producing PVC granules with different filler and filling grades vibrating fluid bed coolers are used for cooling after the hot-cut. The product will be cooled down from typically 160 °C after the hot-cut down to 40 – 60 °C at the discharge of the vibrating fluid bed cooler. Lower temperatures at the discharge are possible depending on the process requirements. A perfect execution of the fluid plate enables an efficient cooling – independent of the particular throughput and layer thickness of the product.

The exhaust air will be dedusted with a filter solution optimized for the application and finally fed to the environment. The JOEST vibration fluid bed cooler will be delivered with a cyclone separator – to extract the pneumatically conveyed product from the hot-cut of the process air – as well as with process and exhaust air system. The scope of piping will then be adapted on the respective operating and installation situation. A start-up gate for product discharge during system start and stop procedure is also part of the scope. Directly after the fluid bed cooler a classifying screen can be installed.

Different sizes and design variations are available. Already the standard design is made under consideration that product contacted parts are easy to clean. For higher cleaning requirements advanced technical solutions are obtainable.

When fertilizer are produced a drying process is required after the granulation, so the product can be packed and stored. A gentle drying process is necessary to keep the grain size distribution processed in the granulation nearly unchanged.  To  meet  exactly  the  customers’  requirements  JOEST  supplies  a  drying  system,  consisting  of  two vibration fluid bed dryers connected in series with multilevel air duct.

The product, which is still moist after granulation, is conveyed continuously to the first vibrating fluid bed dryer. It will be streamed with temperature-controlled hot air (re-heated exhaust air from the second dryer) in the drying area, meanwhile dried and fed to the subsequently arranged second fluidized bed dryer. The second vibrating fluid bed dryer is equipped with a drying and a cooling zone. In the drying zone the product is streamed with temperature-controlled hot air (ambient air heated with natural gas burner) and dried. In the cooling zone, situated directly after the drying zone in the same machine it will be finally dried and cooled with ambient air.

The drying zone of the second dryer is – according to the drying characteristics of the product - designed for operation with a reduced hot air flow. Due to the multitude of different formulations the second vibrating fluid bed dryer is equipped with an electronic adjustment of the angle of attack during operation. This tool enables the control of the product layer - and therefore directly the retention time of the product in the drying and cooling area by adjustment of the angle of attack.

The exhaust air of the second fluid bed dryer with low water content is sucked off from the dryer and fed to a steam-heated air exchanger. Reheated to the required air temperature, the air is blown as drying air to the first vibrating fluid bed dryer. The exhaust air of the first vibrating fluid bed dryer is de-dusted in an exhaust air filter and finally blown to the environment.