LEWCO, Inc. recently delivered a large walk-in oven to a global market leader for electrical insulation products. The application involves heating rolls comprised of mica, resin, and fiberglass. The rolls are loaded onto carts and placed in the oven. Each cart can hold up to six rolls. The finished product has a variety of uses, such as electrical and thermal insulation of various machines as well as insulation of fire resistance cable. The oven, model EWT05FD, is heated by direct-fired natural gas and has a maximum temperature of 500°F., with a temperature uniformity of +/- 5°F.
The oven was installed with a pneumatic vertical lift door for an easy loading/unloading process. To keep operators safe, the door is equipped a safety pawl catch device, which prevents the door from falling in the event of equipment failure. Due to flammable volatiles present in the workspace, the oven had to be designed to NFPA 86 Class A standards. In accordance with NFPA, the exterior of the oven was built with 3/16” plate and reinforced with structural steel. This design provides explosion resistance rather than the alternative explosion relief, which could not be achieved due to space limitations. As an added safety feature, fire suppression ports were included to help control damage in case of fire.
The oven features a Eurotherm Nanodac temperature controller and redundant high-limit controller. This controller has a multitude of notable capabilities, such as a serial communication port, deviation band, ramp/soak programming, and a 4-channel data logger. Two Eurotherm Nanodac slave units were also installed to provide an additional 8-channels of data logging. The software for the data logging is built into the controller, providing the user with easy access to download batch information via USB.