21 COMMUNICATION ISSUE There is a great amount of detail required when specifying how each pneumatic transport system should be considered for configuration. Since this type of equipment is usually part of a larger system containing upstream and downstream components, there's a lot of scrutiny needed for proper equipment selection and operation. Depending on the characteristics of items such as sand type, size of the product supply, direction changes, elevation changes, destination characteristics, silo location, level controls etc. thought must be given to properly account for each item and how it affects the installed system. When one item of information is missing or skipped, serious issues can develop. Could you imagine the issues that might arise if the plant needed more sand and a larger pipe had to be installed? Every installation for the most part is very different. It is our job to give the customer clear and concise information and design configuration based on our equipment’s standard operating practices so that the customer can fully understand what the machine or system will (or will not) do. The way to illuminate Pneumatic Conveying Details For Improved Operation or lessen assumptions is clear communication based on known predictable practice. While we have worksheets that detail the information we need, they don’t necessarily explain the features of the system so that you can also make informed decisions. The best guide for anyone looking to convey sand was written by Chris Doerschlag, the former owner of Klein. Chris details the “What to look for” and provides hints for improved installation and operation. What I really think he does best is explain the key considerations to understand your system options and operation. WHAT TO LOOK FOR? Hints for improved installation and operation Whenever dry and granular materials such as sand are handled JIM GAULDIN Chief Sales Engineer Klein Palmer Inc. ARTICLE TAKEAWAYS: • Materials best for dense or dilute phase • Importance of pipe connections & bends Continued on next page in bulk volume pneumatic air conveying should be considered. This includes all sand handling systems such as the raw sand supply and distribution for core making and molding systems, reclaimed sand and shell sand. For powders and other fines such as bond materials, iron oxide, etc. fluidizing or dilute phase systems should be considered. Part of the analysis should always include a particle size distribution check of the material. If a material is made up of a mixture of ingredients with different bulk densities and a large range of particle sizes, air conveying may not even be a choice at all. If in doubt, check with the material vendor or conveying system supplier. FREE FLOWING MATERIALS The materials should always be dry and free flowing. If larger, hard lumps of material are present a screen or an attrition device (depending on the goal) should be installed upstream of the blow tank. System capacity is also influenced by the dust and moisture content of the material. The higher the dust and moisture content, the lower the flowability and / or capacity. If supply air pressure drops below design conditions, capacity will decrease and may even stop if below a certain value. When distributing sand to the core room the transport air should be free of any moisture. Moisture in the sand causes problems with some binder systems (especially cold box)
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