Wolf RT362F, Technical & Service Manual

Page: 17 / 88

Theory of Operation
RANGES & & R RANGETOPS
2-5
Types of Burners:
Blue Flame Burners - All Wolf open surface burners, French Top burners and the "U" burner in the oven are blue
flame burners. With this type of burner, primary air is mixed with the fuel gas before the gas reaches the burner
ports. An orifice is used to regulate gas flow to the burner. Air which is mixed with the gas inside the burner body
enters through openings in the burner body. A shutter or venturi tube is used to adjust the size of these openings
and control the primary air. Gas and air mix in the mixing tube or throat, which then exits the burner ports where it is
ignited. Secondary air is air from around the flames. The flame produced has several zones, each represents a
stage in burning of the gas. The burner tip has a thin dark blue cone called the inner or primary cone. A lighter
cone called the outer cone, surrounds the inner cone. Air around the flame diffuses into the flame to burn at the
outer cone. If conditions are perfect, products from the inner cone burn here. The final products of burning are car-
bon dioxide and water vapor. An outer mantle surrounds the outer cone where burning is usually completed. It is
nearly invisible and glows only because of the high temperature of the final combustion.
Infrared Burners - Wolf gas ranges also use two types of infrared burners. The under-fired application for the char-
broiler and the griddle uses a porous refractory ceramic tile burner. (See Figure 2-2) An over-fired screen type
burner is used in the oven broiler. With these two types of burners, a substantial amount of energy output is in the
form of infrared radiant energy. With infrared heat, thermal energy is transmitted through space without heating the
medium through which it travels. Infrared energy is usually not affected by air flowing between the burners and
heated surfaces because of the burner’s numerous and tiny flames. This type of heat is very efficient and compact.
The under-fired refractory infrared burner requires 100 percent primary air and is designed to have a hot glowing
burner surface. The flame burns close to the burner surface at a high temperature. In the case of the over-fired
screen type oven broiler, it does not require 100 percent primary air since sufficient amounts of secondary air can
easily reach the screen where the gas is burning.
NOTE: There is no shutter on infrared burners for adjusting the primary air and there is no change in orifice size for
different altitude.
Figure 2-2. Infrared Burner (Under-fired Application for the Charbroiler or Griddle Shown)
Porous Ceramic Surface