LEWCO, Inc. recently delivered a large conveyor oven for a manufacturer of foundry supplies. The oven, which is rated for a maximum operating temperature of 500°F, is used to dry ceramic fiber products. The finished products are used for a variety of applications.
The oven features two direct-fired, natural gas heater-boxes with a capacity of 4,000,000 BTU’s/HR each. The oven is equipped with two 30,000 CFM circulation fans and two 8,000 CFM exhaust fans which include air proving circuits that are electrically interlocked with the heating circuit. The high-efficiency circulation fans and integral plenums deliver uniform “dual vertical” airflow throughout the oven workspace. “Dual Vertical” airflow refers to hot air being supplied to both the top and bottom of parts.
Due to the parts entering the oven wet, a stainless-steel conveyor belt and slider bed were included. Insulated pans are installed on the entrance and exit openings and pneumatically actuated allowing operators to adjust the openings for different parts. The oven is also supplied with insulated bolt-on access panels for easy access to the oven chamber for service and maintenance.
Controls include a Eurotherm Nanodac temperature controller and redundant high-limit controller. A PLC (Programmable Logic Controller) is interfaced with a remotely mounted touchscreen HMI (Human Machine Interface) allowing the customer to easily control all oven and conveyor operations from one convenient interface. A manual push button station was included at the loading end of the conveyor oven for operators to initiate an index mode. The actual distance of the index can be adjusted on the HMI screen. A variable speed drive is included and allows the conveyor speed to be adjusted from 0.20-0.80 feet per minute.