A central dryer is a system that provides a single source of dry, unheated air that is distributed to multiple material hoppers. Each hopper has its own heater, blower, and controls, allowing for the drying of multiple materials with varying drying parameters using the same dry air source. This is achieved using either a dual bed desiccant dryer or a desiccant wheel dryer as the central dryer. The system is designed to provide a centralized and automated method of drying plastic resin, reducing the need for individual drying hoppers and streamlining the drying process.

To implement the system, several drying hoppers equipped with heaters, blowers, and controls are needed, and are supplied as ‘central drying assemblies’. These assemblies are connected together using manifolds that carry the dry process air to the drying hoppers and the return air back to the central dryer in a closed loop. The air is re-dried and circulated back to the drying hoppers, allowing for consistent and controlled drying conditions for multiple materials.

The operation of a central drying system involves several components, including a central dryer, a conveying system, and individual drying hoppers. The plastic resin is first transported by the conveying system to the central dryer, which uses a heating element and a desiccant material to dry the resin. The dried resin is then transported by the conveying system to individual drying hoppers, where it is stored until it is needed for manufacturing.

The central dryer typically uses a desiccant material, such as silica gel or molecular sieves, to remove moisture from the air used to dry the resin. The system may also include a blower to circulate the drying air and sensors to monitor the temperature and moisture levels.

The central drying system offers several advantages over individual drying hoppers, including increased efficiency, reduced energy consumption, and improved quality control. By centralizing the drying process, the system can provide consistent and controlled drying conditions, ensuring that the plastic resin is of high quality and suitable for use in the manufacturing process.

Additionally, the central drying system can be customized to meet the specific needs of a plastics processing plant, with options for different conveying systems, drying capacities, and control systems. This allows the system to be tailored to the requirements of different manufacturing processes and products.