Gas-fired Dryer for Wide Nonwoven Webs
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.
This high velocity hot air impingement dryer is used to dry a waterbased silicone finish on a spunbonded polyester nonwoven web that measures 210 inches wide. Glenro's special design allows our customer to run the web line at fast speeds, despite the web's wet pick-up. This system is gas-fired.
The turbulence created also helps to exhaust vapor from the process to accelerate drying time. 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, ductwork 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 air nozzle plenum inside this high velocity hot air impingement dryer includes exhaust tubes spaced evenly across the dryer, as seen here. Turbulence created by incoming air helps to speed evaporation and exhaust of liquid components in the product finish, and the exhaust tubes further speed the process by immediately removing vapors from the process. Glenro engineers carefully calculate, model and test air impingement nozzle configurations, as adjustments can result in gains in processing speeds.
The dryer includes a complete integrated control package, built into a NEMA 12 enclosure. The system includes all necessary electrical and gas controls, as well as operator interface components. A PLC, specifically programmed by Glenro, controls temperature in each of two heat zones.
Headquartered in Paterson, New Jersey, Glenro Inc. provides process heating engineering and equipment for a wide range of industries and applications especially in web and fabric processing.
Edited by Anndrea Vorobej