Rotary Airlock Valves or Blowing Seals
Rotary valves provide controlled product flow from bulk bag unloading station to the down stream system. Dry bulk materials can be fed into mixers, tanks or other mechanical conveyors through rotary airlocks. Blowing seals are used to feed pneumatic conveying systems and ensure sealing of pressurized air in the pipeline.
Bulk solids in the big bags can be transferred to other handling systems with the help of screw conveyors installed below the big bag unloading unit. Screw conveyors can be used to transfer products to packaging machines, production lines, mixers or other similar equipment.
Slidegate valves can be installed below the discharge hopper of bulk bag unloading station. Product flow speed can be controlled by adjustable valve blade. Manual handwheel or pneumatic piston can be used on slidegate valves depending on type of application.
Butterfly valves placed on the big bag unloading system are simple valves used to open and close product flow in short time. Butterfly valves can be controlled by manual handle or pneumatic actuator.
Batching and Dosing System
Dosing systems feed processes with controlled amount of bulk materials. Depending application requirements, volumetric or gravimetric dosing systems can be installed on bulk bag unloaders. PLC or computer controlled dosing systems are available.
Pneumatic Conveying System
Instead of mechanical conveyors, pneumatic conveying systems are preferred in processes where the bulk bag unloading stations are far from feeding points. Pneumatic conveying equipment and pipeline are connected to bulk bag unloading systems. Powdered or granular bulk materials are transferred from bigbags to pneumatic conveying system and then conveyed to the required points. Depending on type of application, pressure conveying system or vacuum conveying system can be installed.
Dense Phase Pneumatic Conveying System
Big bag unloading stations with built in dense phase pneumatic conveying systems are used in applications where high conveying capacities and long distances are needed. Big bag unloading hopper is installed above a pressurized tank also known as pressure vessel. Several big bags are unloaded in one time to the pressurized tank. High pressure air is used to pressurize the tank and send the product through the conveying pipeline. Dense phase pneumatic conveying systems are generally preferred for materials like cement, calcium carbonate, PVC, soda and fly ash where high transfer capacities are needed.
Outlet of big bag unloading station is kept free of any equipment. Unloaded bulk solids move freely to down stream system.
Bulk solid transfer equipment are used to transfer powdered and granular materials from big bag unloader outlet to required destination. Mechanical or pneumatic conveyors can be used according to application needs.