Why Do They Call It Angel Hair When It Devils You?
Angel hair or streamers are a common problem for any plastic processor who pneumatically conveys a soft resin such as LDPE. It occurs when pellets slide along the wall of a tube and generate friction and heat. This most often happens in a direction change such as an elbow. Although it cannot be completely eliminated, there are steps to significantly reduce the production of the streamers:
- Treat the interior of the tube with a directional shot peen or internal groove. This tends to cause pellets to tumble instead of sliding along the wall. This piping is available from several sources.
- Discuss the problem with the supplier of your vacuum conveying system. You want to make sure that the velocity of the plastic pellets as they are conveyed throughout the system does not exceed the recommended speed as determined by the manufacturer.
- An aftercooler for the pump will reduce the conveying air temperature and lessen the opportunity for streamer production. However, this step requires a discussion with your system supplier to determine the correct size aftercooler and any other changes (ie. Muffler)
- Discuss the problem with your supplier. They may be able to offer further assistance or suggestions to help you.