Air Impingement Dryers

Air Impingement Dryers

The Air Impingement Dryers are typically utilised in the coating sections of board machines. The systems are custom designed for your process and can be either gas or steam heated.

Operating Principle

Hot air is made to impinge in a plug flow manner on a moving loosely formed bed of wet feed. Moisture evaporates as the material traverses along the length of the bed and is rendered dry at the discharge end. Humid air is continuously exhausted. The dryer is employed for wet crystals which are very fragile as well for wet performed feeds which are not suitable for the normal belt dryer operation.

Special Features

• Suitable for well aerated beds of preformed, crystalline or granular wet feeds.
• High evaporated efficiencies due to the impingement action in plug flow manner.
• Gentle drying
• Uniform drying
• Material from remains intact
• Low power demand
• Continuous operation
• Shear sensitive materials can be handled.

Applications

• Menthol Crystals
• Yellow Iron Oxide
• Pigment
• Organic Crystals

Modern Air Impingement Technology

The ultramodern hot air impingement dryer is used to dry a water based silicone finish on a spun bonded polyester non woven web that is 210 inches wide. The gas-fired dryer system uses high velocity hot air impingement nozzles mounted beneath the product to apply hot air to the web at a right angle. Hot air impingement breaks through the boundary layer of air that surrounds the moving web and transfers heat to the product to vaporize liquids in the coating or finish. The turbulence created also helps to exhaust vapor from the process, which speeds further drying. Impingement air is exhausted from the dryer through return tubes, which are evenly spaced across the dryer. High velocity hot air impingement is extremely effective in applications where large quantities of water must be removed from a saturated or coated product. The complete dryer system measures 11.75 feet long by 21 feet wide by 11.8 feet high, including the dryer enclosure, blowers, duct work and structural steel support frames. The dryer enclosure is constructed of aluminized steel with stainless steel trim. Its walls are extensively insulated. Three bolt-on plug doors with handles allow access to the dryer's interior for maintenance, and two pressure gauges display supply plenum air pressure. The new high velocity hot air impingement dryer also includes a mechanical subsystem that raises the dryer's upper cap 24 inches above its base, allowing complete access to the product web. Motorized screw jacks raise and lower the upper cap, and are operated from the system's central control panel. Dryer halves are gasketed to form a tight seal in the closed position.The dryer includes a complete integrated control package. Built into a NEMA 12 enclosure, the control system includes all necessary electrical and gas controls, as well as operator interface components. A PLC, specifically programmed by the company, controls temperature in each of two heat zones. The dryer system is shipped assembled, pre-wired and pre-piped for easy handling and installation.