PT ZONE: General Questions
General Blending/Dosing Questions:
Question: Can one size of auger on my blender be used for all my additives, for all of my molding jobs?
Response: In many cases, yes, if the additives are of a similar nature, IE: pelletized and fed roughly at the same rate. If the additives are of a similar shape and size, the only sacrifice you'll have to make, when metering measurably more additive, are reduced overall blender throughputs. It will take more time with a smaller auger, than with a larger one. If switching between additive forms, IE: pellets and powders, you will have to switch augers and possibly even dosing units to prevent bridging and other nuisance flow problems with powders.
Question: I have a 5 year old blender with thumbwheel settings for color and regrind. is it possible to get an upgrade to a touch screen control for this unit? Will it be difficult for my people to operate?
Response: Upgrades to touch screen controls for the very popular thumbwheel controlled blenders are available! And typically, users find the transition between thumbwheels and the new touch screen very easy, since the touch screen images mimic thumbwheels.
Question: Is there a recommended way to clean a blender when preparing for a new recipe?
Response: Many processors develop their own methods for cleaning, and most approaches are based on how thoroughly they need to be cleaned. For instance, are all materials going to change, or just the additives? But in general, top to bottom is best. Start with the main material or additive supply bins and clean downward. If the bin is equipped with a loader or receiver, it should be cleaned at this time as well. By cleaning top to bottom, all dust, fines and other residue from the previous materials are allowed to funnel down through the blender where they can finally be removed as the mixing chamber is opened and cleaned out. Be sure to observe all possible safety precautions (disconnect power, watch out for sharp mixing blades, etc) and be sure to make the job as easy as possible by considering some of the clever accessories that are available to make draining and cleaning even easier. Drain ports, pneumatic lifters for loaders, removable additive bins, etc.
Question: I have placed my blender on a mobile stand so I can move it to where I need it, but it now mixes poorly on start-up since the materials flow right through it! What am I missing?
Response: Basic blenders are made to be machine mounted so that the processing machine itself governs when blending occurs. When mounted over an open vacuum box, barrel or gaylord, there is nothing to regulate the material flow and allow mixing to take place (until the vessel backs up). A flow regulator valve is required for the bottom of the blender, above the vacuum box or collection container, to stop the flow of material until suitable mixing takes place. Luckily, these optional valves may be fitted quite easily and most blenders are equipped to control the valve's pneumatic slide gate with timer settings you can adjust, right from the blender control.
Question: I am considering the use of liquid color for the first time. Can I make it work with my existing blender?
Response: In many cases, yes. Liquid color is introduced into the blending process just like any other additive. Your checklist for compatibility is:
You must have the right equipment to meter the liquid. This will be a peristaltic pump or a compressed air diaphragm pump.
Is your blender equipped with the control means to regulate the flow of liquid? If not, a separate liquid control will be necessary.
Can your blender handle the introduction of liquid? Will flappers or valves tolerate the introduction of a liquid? Are accommodations available for the liquid coloring nozzle to be installed? Blenders with cast aluminum mixing chambers can be fouled with liquid color. Stainless steel lined mixing chambers are most suitable.
Popular weigh scale blenders using thumbwheel controls ARE readily adaptable for the use of liquid color. Consult the blender manufacturer or even the liquid color supplier for more details.
Question: I commonly add wood flour to my process via a large, bulk blender. But I have recently changed sources for the wood flour and the new source does not flow well and I constantly have bridging or very irregular flow problems. Is there a solution?
Response: Yes. First, depending upon how accurate your process needs to be, the use of a gravimetric blender is strongly advised, to be sure that when ingredients of the blend are interrupted, for whatever reason, the blender will make every attempt to still meter the correct amount by weight and/or you are alerted. Secondly, wood flour is best metered by a dosing unit that includes not only the right auger and housing combination for optimum, accurate metering, but also includes flow enhancements in the additive supply hopper to keep the material from bridging. These enhancements include an agitator that stirs the supply while metering is taking place, to assure movement or bridge breakers designed to specifically knock down common bridging.