Specifications

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10. WATER HEATERS AND COFFEE MAKERS
10.1 FUNCTION OF WATER HEATERS
It is used to heat small or bulk quantity of water. The heating element of water heaters
converts electric energy into heat by which water inside the heater gets heated due to convection.
10.2 TYPES OF WATER HEATERS
The water heaters are available in various forms. They are
i) Electric Kettle ii) Immersion water heater iii) Storage water heater (Geyser)
10.3 ELECTRIC KETTLE
It is used to heat small quantity of water. The heating element is fixed inside the kettle. When
electric supply is given to the heating element, it gets heated and hence water inside the kettle gets
heated due to convection. Types of Electric Kettle: i) Swan neck type i) Saucepan type
Swan neck type: In this type, the heating element is of tubular immersion type as shown in
Fig.10.1. It is concealed inside a hollow tube and mineral insulated. The heating element is
made up of Nichrome coated around with magnesium oxide to ensure that the element does not
directly touch the wall of the kettle body. The heating element is fixed at the bottom of the kettle.
The simple form of Swan type kettle is shown in Fig. 10.2
Precautions:
i) Water level always should be above the heater element otherwise the element gets
overheated and may burst.
ii) The kettle should not be switched ON with out water.
iii) The water should not be touched when the supply is ON.
Saucepan type: The heating element in this type is wound around a flat mica sheet as in iron
box. Here the heating element is placed in separate room i.e. outside bottom part of the heater
body and is covered by bottom cover. The construction of saucepan type is shown in Fig. 10.3
Heating element : The heating element made of Nichrome ribbon resistance wire wound over
flat mica sheet. This is place between tow circular sheets, so that the Nichrome wire may not
come in contact with any metallic part of the kettle. The two ends of the heating elements are
connected to the outlet socket terminals of the kettle through two brass strips.
Fig. 10.1 - Swan neck type water kettle Fig. 10.2 - Kettle heating element