Many problems in the pneumatic conveying of resin centers around material build-up in the lines. Often times lines get contaminated from a shredded gasket (unless the Instalok coupling is used), long thin lines of resin, tiny particles of resin, dust, etc. These unwanted materials have been called many different things: fines, dust, tails, streamers, angel-hair, snakeskins, etc. But what exactly is the difference between these terms? Is there one?
From my understanding, streamers, angel-hair, and snakeskins are essentially the same thing. During conveying, heat develops due to friction between the resin pellets, the tubing wall and the conveying air. This friction heat in turn causes the resin pellets to soften. When the softened resin pellets come in contact with the tube wall, they smear and over time the smears become strands of material that fall into the air stream in the form of angelhair or snakeskins. This can result in line blockages that may ultimately reduce the efficiency of the resin transfer system.
Fines appear to be the catch-all phrase for material that isn’t an intact resin pellet, but isn’t as long as a streamer. Tails are a more specific form of a fine – when the pellets are cut, at times the cut isn’t clean and results in a little material left at the end of the cut. Tails and fines, in theory, seem to be less of a problem than streamers in terms of pipe blockage and material build-up because of their respective size.
What’s your experience with angel-hair or fines been? What solutions have worked for you if it’s a problem?
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