PECM Issue 23 2016 - Page 115

Valves & Flow Control Made in Britain TELEPHONE Handling Adhesive Products Handling Adhesive with Rotary Valves Products with Rotary Valves Adhesion is the tendency of dissimilar particles or surfaces to cling to one another. prevent the product from plugging. dhesive products tend to than drop through style rotary valves (Note: Under positive pneumatic come from the food and because the rotor conveys directly in conveying conditions two rotor vanes chemical industries. Fatty, to the conveying line. This is especially should be sealing at all times to dhesion is the tendency of dissimilar particles or oily products with high pertinent if the connection pipes have prevent excess leakage air). Product surfaces cling to one another. Adhesive products moisture can tobe stic y as been designed to efficiently purge contact surfaces should be polished or tendstarches, to come fromwax the food are milk powders, - and chemical theindustries. rotor pockets. Valves designed have a non-stick coating applied and Fatty, oily products with high moisture (+20%) can gelatine powder, lactose, soap noodles, to provide a smooth ull flow o avoid narrow or multi-vane rotors, be sticky as are milk powders, starches,conveying wax - gelatineair through the convey line maltodextrine powders. even with polished surfaces and nonpowder, lactose, soap noodles, maltodextrine powders. pipe connection with minimal pressure stick coatings because highly adhesive Adhesive products will stick to the drop will also aid product discharge, A larger valve running slowly with less rotor vanes and scalloped rotor pockets will Adhesive products will stick to the valve internals causing the running products can still adhere to them. valve internals causing the running preventing the possibility of line also provide a wider rotor pocket that will aid product discharge and prevent the clearance to block, which can lead to the valve seizing up. The product can plug in product from plugging. clearance block, which causing can lead blockage / lodgement and thus product(Note: Under positive pneumatic conveying conditions the bottomto of the rotor pockets reduced throughput, line blockage and Do not specify replaceable bladed two rotorhygiene vanes should to later theproduct valve degradation. seizing up. The product is be sealing at all times to prevent excess leakage air). Highly adhesive products can contamination, be very poor flowing vital where rotors for sticky because Product contact surfaces should be polished or have aproducts non-stick coating applied can plug in the bottom of the rotorthe desired throughput a factor. difficult to which makes the sizing of a valve to achieve product will stick to the ledge at the and avoid narrow or multi-vane rotors, even with polished surfaces and non-stick pockets causing reduced calculate.The solution is to makethroughput, sure you choose the correct valve. Blowing Seal bottom ofcan the the route of the coatings because highly adhesive products stillblade adhere in to them. line blockage androtary latervalves product A larger valve with reduced capacity (Blow through) style with scalloped rotor pockets are usually better rotor pocket and do not use closed degradation. rotor will provide a wide suited to adhesive products than drop through style rotary valvespockets because the rotors product will hold upproduct on the Do not specify replaceable bladed rotors–for sticky products because will rotor conveys directly in to the conveying line. shallow poc et con guration. his stick to the ledge at the bottomclosed of the blade in the route of the rotor and rotor end disc and it pocket can also Highly adhesive products can be very is proven to aid discharge of sticky do not use closed rotors – product hold upthe on the closed rotor discdisc and it getwill behind closed rotorend end This fl isowing especially pertinent if the pipes have been designedand to also prevents poor which ma esconnection the si ing products thebehind product can also get the closedand rotor end discup anduntil build up until the valve seizes. build the valve seizes. the rotor pockets. Valves designed to provide a smooth flow of efficiently a valvepurge to achieve the desired plugging in full the bottom of the rotor of conveying air through thecalculate. convey line pipe connectionpocket, with minimal throughput diffi cult to as pressure there is noOn narrow bottom drop through rotary valves,On rotordrop pocketthrough purge ports can be drilled to aid rotary valves, rotor drop will also aid product discharge, preventing the possibility of line blockage section for product topocket adhere to. and finally a product sample can be useful to determine the discharge pocket purge ports can be drilled to aid / lodgement and thus product contamination, vital where hygiene is a factor. The solution is to make sure you level of adhesion and product flow prior to the supplier quoting. A larger valve with reduced capacity rotor pockets will provide a wide shallow poc et discharge and nally a product choose the correct valve. lowing eal A larger valve running slowly with less pocket configuration. This is proven to aid discharge of sticky products and also sample can be useful to determine the Email: sales@rotaval.co.uk Tel: +44 (0) 1249 651138 (Blow through) style rotary valves prevents the product plugging in the bottom with of the rotorrotor pocket,vanes as there and is no scalloped rotor pockets level o adhesion and product flow prior scalloped rotor pockets are to usually will also provide a wider rotor pocket Web: www.rotaval.co.uk narrow bottom section for product adhere to. to the supplier quoting. better suited to adhesive products that will aid product discharge and A A Issue 23 PECM 115