Vacuum loader/conveyer

Because of the railroad-car shortage that has persisted for many years, boxcars are often used for bulk materials. Lined with suitable materials to prevent contamination and with special bulkheads at each door, these cars are acceptable substitutes for covered hopper cars even though unloading is more difficult. Vacuum conveying wands are used to pick up the material, as are front-end-loader-type vehicles. 

Two basic types of pneumatic conveying systems have been adopted for railcar unloading service the vacuum system and the combination negative-positive pressure system. Each possesses certain advantages which make it useful for different types of applications. Figure 7.15 shows schematically a straight vacuum type of loader that utilizes a silo-mounted vacuum chamber. In this type system, the vacuum pump... 

Dry blends can be transported to the molding area manually or via modified pneumatic systems. Vacuum systems are not desirable. A tube spiral wire conveyor has been used successfully to transport dry blend from the floor level to an overhead hopper. A bulk loader operating from a 1000-lb metal container, the contents of which is dumped into an auger feed system, has also been used. The augers have been designed especially for conveying blends. 

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