Materials Handling
Pneumatic conveying is an ideal method of moving materials around sites, between sites and from delivery points. The latest conveyors can even transport material over a mile in distance.
Die Druckluftfördertechnik ist eine ideale Methode, um Material an einem Standort, zwischen mehreren Standorten und an Warenlieferstellen zu transportieren. Die modernsten Fördersysteme sind sogar in der Lage, Material über eine Strecke von 1,6 km zu transportieren.
Le convoyage pneumatique est une méthode idéale pour déplacer des matériaux au sein des sites, entre sites et depuis les points de livraison. Les nouveaux convoyeurs peuvent même transporter des matériaux sur des distances supérieures à 1,5 km.
Pneumatic conveying rises to materials handling challenges
F
ollowing a change in US law, one of the world’s largest producers of folding cartons and coated boxboard packaging had the opportunity to earn a significant tax credit. This led the company to
rely even more on energy provided by a bio-mass by-product of their process. Black liquor is the by-product used to fuel the
on-site power plant that creates as much as 66 per cent of the electric energy used by the mill. To prepare the black liquor for the power plant, salt- cake needed to be hauled in by rail, transferred to a storage silo, and metered into a wet mix tank. The company selected United States Systems
(USS) to design and manufacture the complete salt cake conveying, storage, and mixing system. Project objectives necessitated an efficient system with the ability to unload an entire railcar in less than one operator shift. USS met the design challenges by engineering a continuous flow airlock system to meet project specifications.
properly. USS engineered the system to minimise the migration of moisture into the spout by utilising a slide gate to isolate and seal the moisture from the airlock. However, when the gate is open and the salt cake is being added to the wet tank, moisture might still migrate upwards. To solve that potential problem, engineers at USS
devised a way to purge the zone below the airlock with compressed air while the gate is open. The compressed air causes a net downflow of air and minimises the moisture migration upward into the spout. The solution proved successful and they are now unloading up to 2700kg/h of salt cake to the wet mix tank. USS technicians provided the start-up assistance to get the salt cake moving quickly and trained personnel in operation and safety. For another USS project, a large warehouse
management firm needed a total system solution to capture material and convey it into an overhead silo for bulk bag filling. The company required a dependable pneumatic conveyor system that could run without unscheduled downtime and meet the high material transfer rate of 14 500kg/h. The machine also needed to run automatically to save time and cost. The firm asked USS to design and manufacture a large version of a small ultra-portable diesel-driven system they already own that was built by USS decades ago. USS listened to the customer and appreciated
its positive experience with the system and explored alternative solutions. Although USS builds diesel- driven systems, the energy costs and safety issues involved in the constant refuelling of a diesel-driven system made it an undesirable solution in this case, where the solution needed to be portable but not ‘ultraportable’. The problem was two-fold: to design a system
to keep energy costs down and one that could be transported elsewhere if needed. After careful consideration of these unusual design
requirements, USS proposed a custom-engineered total system solution: an electric-powered, skid- mounted USS Venturi 30 pneumatic conveyor system including blower package and controls. Other design requirements resulted in the
Fig. 1. The demand for pneumatic conveying solutions remains robust.
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A concern expressed by the salt cake supplier was that moisture from the 93°C liquid in the mix tank would rise through the rotary valve and make its way into the silo cone. Moist salt cake will not flow
inclusion of NEMA 4 rainproof control panels that allow the operator the flexibility to run the conveyor in either automatic or manual modes. Meanwhile, Clyde Process Solutions (CPS), another global provider of pneumatic conveying
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