1.0 Introduction
Heat is said to be energy in transient by virtue of temperature difference. It is a known fact that heat generated an through various means such as conduction, convection and radiation as in radioactive ensure.
Heat energy occurs chemically when a chemical reactions of a strong acid reacts with a strong base. Heat is either liberated external (Exothermic reaction) or absorbed internally (Exothermic reaction). Heat also occur mechanically when an automobile engine is working. Heat generated results to hotness of the engine surface and environment as a result of fumes from the exhaust pipe. Heat is an effect generated in connection with complete continuous flow of elections in a circuit.
The electric kettle as a heating device requires electricity conduction to generate heat to perfect its friction. Electric kettle as a very important equipment used in our homes, hospitals, laboratories and industries for heating and boiling of fluids.
It is a device in which the mechanism of heat transfer is studied and highly felt. The heat transfers into the liquid by firstly; the metal conducting heat probably from electric source in contact by conduction and transfer the heat in the liquid causing the molecules of the liquid to expand colliding with one another exerting pressure and at equal prevailing atmospheric kettle pressure the water boils. Heat transfer mechanism in an electric kettle is a combined process of conduction and convection.
In progression, the mass of the liquid before boiling remains constant and the liquid become, less dense that the cold liquid surrounding it. Both layers of the liquid exerting pressures moves up and down till the whole liquid acquire a vapour pressure which when equal with the atmospheric pressure boiling occurs and the liquid is said to reach its boiling point.
1.1 Aim of the Project
The object of all construction project is to test students ability to construct with given specifications.
This project is specifically for the construction “S” litre electric kettle which will boil at 100oc (373k) and capable of using 220 — 240 voltage and voltage and 13 — 15 amperes.
Moreover to construct a vessel that low the under listed advantage which is for superior to other methods of heating e.g using gas, cool and fire etc.
(i) Cleanliness:
Since neither dust nor ash is produced in electric heating. It is a clean system of heating requiring minimum cost of cleaning. More also, to be heated does not get contaminated .
(ii) ND Pollution:
Since no flue gases ate produced in electric heating, no provision has to be made for their exit.
(iii) Economically:
The lost of maintenance is not much and it doesn't occupy much position.
(iv) Easy Control:
It is easy to control and regulate the temperature of an electric furnaces with the help of manna or automatic devices.
(v) Special heating requirement:
Such as uniform heating of a material or heating one particular portion of the job without affecting its other parts or heating with no oxidation can be met only by electric heating.
1.1 Definition of Terms
Boiling Point:
This is the temperature reached by a liquid when its vapour pressure is same with the atmospheric pressure at room temperature. In other words, it is the temperature at which water boils and it normally 100o for pure substance such as water.
At this point, when the temperature is reached the electric kettle can be seen scientifically as a control instrument that will regulate any system or a system if too high by stripping off.
Vapour Pressure:
This is the pressure exerted by liquid molecules at its boiling point it is the force per unit area of the liquid layer in contact. Its unit is Newton Rir meter square (N/M2). in the process as it attains its vapour pressure there is a transfer of chemical species (solute) from its initial liquid phase to gaseous phase with a small change in concentration.
This agrees with the analogous theory of heat transfer and mass transfer mechanism in the functioning of electric kettle.
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