coating utility poles takes infrared plus convection
gas-fired radiant/convection systems couple direct
radiant heat with a convection zone. Convection heating
is especially effective for use on parts with a relatively
small diameter and substantial length such as utility
Lighting Standards, Warren, Michigan, manufactures
steel and aluminum lighting poles and related products
in lengths ranging from 10 to 40 feet and wall thicknesses
from one-eighth to one-half inch. The company switched
from liquid solvent based paints to powder coatings
in 1987, curing and drying the products in an electric
the years, a number of system problems became evident,
including insufficient curing of large, light colored
products, and frequent shutdown of the line for maintenance
and element replacement. Electric element replacement
also generated a hefty expense of at least $10,000
eliminate these problems, company management decided
on a combination infrared and convection oven designed
and fabricated by Thermovation Engineering of Cleveland.
Thermovation fabricated a free-standing unit measuring
32 feet in length, eight feet high and five feet wide,
with a maximum capacity of 2 million Btu/hr., sufficient
for the company to easily reach its increased production
goals. Heavy cast-iron premix burners were specified
for extended life and more precise heat modulation.
temperature controllers in each zone of the oven modulate
fuel input to the burners; a non-contact heat sensor
measures product temperature at the oven's exit. The
entire system was tested and debugged at the Thermovation
factory, enabling it to be fully installed and operational
at the customer's facility in just six days.
on United Lighting Standard's production schedule,
the new oven could save the firm more than $100,000
annually in reduced energy costs. Improved productivity
and lower maintenance are important side benefits.
"The number of poles we can put through the system
per shift is up by at least 30 percent, "comments
Bernie Jenkins, United's general manager, "and we're
confident we can easily raise it to 50 or 60 percent.
Also, the excess capacity of the system will allow
us to significantly raise throughput without any major
system redesign or renovation."