Middleby Cooking Systems Group PS200-R68 - Manual (Page 4)

4
SECTION 1
DESCRIPTION
II. PRINCIPLE OF AIR FLOW
Air is heated and then pulled through the fan which
pushes the air into the oven plenum and delivers heated
air into the air fingers. The fingers contain an inner plate
and outer plate which columnate the air and evenly
distribute heated air across the conveyor belt on which
the product rides. Air is then pulled back into the blower
and the process continues.
A. Heat Transfer and How It Works
1. Heat constantly moves from a warm object to a cold
object. Heat moves using three different paths which are
conduction, radiation and convection.
Conduction: This path utilizes surface to surface con-
tact. The pizza dough in contact with the pan is a good
example of conduction.
Radiation: This path has to do with objects radiating
heat. Dark objects absorb heat whereas light or shiny
objects reflect more heat. This is the reason that the
inside of the Middleby Series PS200-R68 Oven is light in
color to reflect more heat back to the product.
Convection: This path has to do with moving amounts
of air. It explains why hot air will rise and cooler air
replaces hot air. An industrial application of this principle
is to incorporate a fan to force the hot air movement which
in turn will increase the heat transfer to the product.
The Middleby Series PS200-R68 Oven has a large fan to
move the hot air through the air fingers and onto the
product so the most efficient bake is achieved.
2. Temperature is the intensity of heat at the point which
it is sensed. As discussed above, heat flows by conduc-
tion, radiation and convection. The speed at which the
heat flows is determined by the temperature difference
between the oven and the food product. The larger the
difference the faster the heat flows to the item that is
being baked.
Figure 1-2
Series PS200-R68 Air Flow
Side View