PC enclosures for food process applications, NEMA 4X
Midwest Plastic Fabricators’ new high-performance thermoplastic custom enclosures are allegedly one-third of the weight of stainless steel and are intended to replace heavy traditional materials. A significant reduction in the weight of the enclosure assembly allows more freedom in machine frame design. Another important feature is that these enclosures do not have draft angles, the result being flawless pivoting for the pendant mount, according to MPF.
The entire enclosure assembly at 55-lb does not require paint, is non-conductive, and is NEMA 4X-rated with a UL94V-0 flame rating. The inner enclosure is 25 x 20 x 5, the outer cabinet 32 x 28 x 8. Other sizes are available including double doors with 3-point latching.
In the application shown, design enhancements to reinforce the structural strength reportedly allow the assembly to be pendant mounted and cantilevered. The assembly consists of an outer enclosure with a large flush polycarbonate viewing window in the door; an inner enclosure with a bottom to top swing hinged door to house the controls which are mounted on a polycarbonate sub panel. The doors use a stainless steel piano hinge. The outer door is secured with ¼ turn latches, and the inner panel door is secured with stainless steel fasteners that screw into brass inserts.
To secure the pendant mount bearings, the manufacturer, Midwest Plastic Fabricators in Aurora, Ohio, reinforced the cabinet with polycarbonate stiffeners that are welded to the inside of the cabinet. This structure allows the cabinet assembly to support the heavy electrical and electronic controls used in today’s computerized industrial control systems.
An added benefit is that the enclosures are available in colors to suit the application, according to MPF. For example, in a meat process plant, a darker color may be preferred in comparison to other food operations that seek a lighter color.
Midwest Plastic Fabricators
– Edited by Amanda McLeman, Control Engineering, www.controleng.com