The dryer works by tumbling the clothing and
blowing air through the drum. The drum has baffles protruding
into the drum to keep the clothes from bunching up. The length
of time the dryer runs and the air temperature are elements of
the various drying cycles.
A motor turns the clothes drum and also turns
a fan (called the blower). The air flow from the blower passes
over a heating element (in an electric dryer) or through a gas
jet (in a gas dryer). The air then passes through the drum and
out the back of the dryer through ducts to the vent which is typically
located outdoors.
A gas dryer uses a burner assembly which is comprised
of a control valve with 1 or 2 solenoids (also called coils),
a gas jet, an igniter and a sensor. When the dryer is started,
the igniter heats up, when the sensor detects the heat, it signals
the solenoid on the control valve to open and release the gas
which is then lit by the glowing hot igniter. The igniter turns
off but the gas jet remains open. The burning jet of gas keeps
the sensor warm which keeps the gas valve open, until the thermostat
signals the control valve to stop the flow of gas.
The dryer cannot operate until the door switch
signals that the door is closed. The start button must then be
pressed to enable the timer control. The timer control either
regulates the length of time the dryer runs or it works in conjunction
with a moisture sensor that measures the water vapor in the drum
to determine when the clothes have dried.
The temperature selector controls the maximum
temperature inside the drum with the aid of thermostats. The heat
turns on and off as needed to maintain the temperature.
