Specifications

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9. ELECTRIC IRON BOX
9.1 DEFINITION
An Electric Iron box is a heating device in which the electrical energy is converted into heat
energy. This heat energy is concentrated on a smooth, flat bottom surface which is pressed
over the cloth to be ironed.
9.2 TYPES OF IRON BOX: 1) Non-automatic Iron box 2) Automatic Iron box 3) Steam Iron box
9.3 NON-AUTOMATIC IRON BOX :
In non-automatic type, the temperature is not regulated. The user has to switch ON or OFF
the iron as per the heat requirement.
Constructional details: The principal parts of the iron box is shown in Fig. 9.1
Sole Plate: It is made up cast iron and it is generally chromium-plated. The transfer of heat
from the heating element to the material ironed is done through sole-plate.
Heating element: There are two types of heating elements. One is made of ribbon shaped
Nichrome (resistance) wire wound around a sheet of mica. This type of element is placed on
the top of the sole-plate as shown in Fig.9.2. Other type is made up of round resistance wire
coiled on a ceramic form and cast directly into the sole plate as shown in Fig.9.3. The flat type
element is replaceable whereas the cast type heating element has to be replaced along with the
sole-plate only. In this type of irons, a pressure plate is not necessary.
Fig. 9.1 Parts of Iron Box
Terminals and power cord: The ends of the heating
elements are connected at the points called as terminals as
shown in Fig.9.4. The electric supply is given the coil terminals
through 3 core power cord.
Pressure plate: It is made of cast iron and the purpose
is to keep the heating element firmly against the sole-plate.
The pressure plate is insulated from heating element by
asbestos sheet of same shape. The asbestos sheet is placed
just above the heating element to prevent the heat developed
in the element traveling upward due to conduction and radiation.
Cover: It comes above the pressure plat. This part covers
the heating element’s internal connections of the iron. It also
serves as a shield to protect the user’s hands from the
generated heat and the electric terminals.
Handle: It is made of Bakelite or ebonite because it offers
high resistance to flow current and it can withstand more heat.
The indicator lamp and power socket are fixed in the handle.
Heel plate: The purpose of the heel plate is to enable
the iron to stand when the iron is tilted back on the rear of its
handle.