Theory of Electric and Microwave Ovens: Chapter 2
Ovens
In this module, we will learn about: Ovens, Need of ovens, History of ovens, and The principle used in ovens. We will also discuss the types of cooking and ovens. Skip to quiz!
Introduction to Ovens
An oven is a tool that exposes materials to a hot environment. The oven contains a hollow chamber and provides a means of heating the chamber in a controlled way. Ovens have been in use since ancient times in different forms and techniques.
Ovens have been used to achieve a wide variety of tasks requiring controlled heating. Ovens are of many different types like toasters, electric, and microwave ovens, and are used for various purposes. Ovens differ depending on their use and based upon how they generate heat.
Cooking is a basic need of humans, and it can be achieved using various ways. Cooking requires heat to cook the food. The heat is generated from open-fire cooking, gas stove, and heating elements in ovens.
Ovens are useful for a variety of cooking processes like:
Baking,
Defrost,
Roasting,
Boiling, and many more.
In ovens, the food is cooked faster than the conventional methods. Modern day ovens are simple to use.
Ovens serve the purpose of:
Faster cooking,
Better cooking, and
Easier cooking.
The food is cooked evenly in the oven. While in a conventional method, the surface in contact with the heat is cooked first, then the others.
For example, heating frozen food can take approximately half an hour on a gas stove. But when we cook it in a microwave oven, the frozen food gets heated in a few minutes. Now let us look at the history of ovens.
In the early part of the 19th century, coal ovens were used. It was cylindrical and made of heavy cast iron. The gas oven was used as early as the beginning of the 19th century. Gas ovens became a very common household cooking method, once gas lines were easily available to homes.
Electric ovens were invented by Canadian inventor Thomas Ahearn in the late 19th century. The popularity of the electric oven was slow to pick up due to the high prices of electricity. By the 1930s, when electricity became cheaper, electric stoves started gaining popularity.
In 1946, Dr. Percy Spencer discovered the heating properties of microwaves while studying the magnetron. By 1947, the first commercial microwave was in use in Boston, Mass. More recently, ovens have become slightly more high-tech in terms of cooking strategy.
The oven is a heating device that uses radiant heat generated by various sources. Radiant heat is a mechanism for heat transfer that does not require a medium in which it propagates. Radiant heat is generated by burning coal using gas burners, electrical coils, and radiation energy.
For example, humans are alive because radiant heat from the sun is available in abundance. Sun’s radiant heat interacts with the Earth, driving important environmental cycles and allowing life to flourish. Cooking is done using the radiant heat available from different sources.
Electric coils are heated using electrical energy and supplied in the required amount to cook the food. There are many electrical coils available depending on the type of material used, similar to filament bulbs.
The electromagnetic radiation transfer the energy at atom levels, the exchange of heat takes place between photons. The radiation energy in the form of microwaves is suitable for cooking purposes.
Cooking is the art of making food for consumption. Cooking is done in various methods and numerous processes, but some are used regularly for daily consumption. Each of these methods uses heat to cook foods differently.
Cooking can be of many types, but some of them are:
Baking,
Roasting,
Frying,
Grilling,
Steaming, and
Boiling.
As we are familiar with the above methods, we will look at the short description.
Baking is cooking food at lower temperatures; usually, cakes and bread are made using this process. Roasting is the process of cooking food evenly on all sides from an open flame or another heat source. It is best for cooking meat, roots, and mushroom-like vegetables.
Frying is cooking the food in an oil bath; often after, breading it, crispy food is made using this process. Broiling is the process of roasting the food from the above side, keeping the liquid as it is. Grilling is the process of cooking food, exposing directly to an open flame or coal.
Types of Ovens
Ovens are of many types, and ovens are categorized based on their:
Process,
Operation,
Heat transfer methods, and
Mounting type.
Let us see the types of the oven in each category.
Ovens based on their process are:
Earth oven,
Gas oven,
Brick oven,
Toaster oven,
Electric oven, and
Microwave oven.
Ovens based on their operation are:
Residential,
Commercial,
Industrial, and
Kiln.
Ovens based on their operation are:
Convectional heating,
Gas,
Electric, and
Radiation energy.
Ovens based on the mountings are:
Wall,
Double,
Slide-In,
Countertop,
Drop-In,
Freestanding, and
Drawer type.
Let us see about different types of ovens.
Earth oven: An earth oven is a pit dug into the ground and then heated by rocks or smoldering debris. Many cultures around the world have used Earth ovens for cooking. Ceramic oven: The ceramic oven is constructed of clay or other ceramic material and takes different forms depending on the culture.
Brick ovens are also another ceramic-type oven. A culture most notable for the use of brick ovens is Italy and its intimate history with pizza. Gas oven: An oven where gas is used for cooking food. It is the standard and basis for the modern gas oven.
Electric oven: These produce their heat electrically, often via resistive heating. It consists of a cabinet where the food is cooked. Toaster ovens are small electric ovens with a front door, wire rack, and removable baking pan. The bread is toasted in a toaster oven, and the slices of bread are placed horizontally on the rack.
Masonry ovens consist of a baking chamber made of fireproof brick, concrete, stone, or clay. Modern masonry ovens are often fired with natural gas or even electricity and are closely associated with artisanal bread and pizza. Double oven: A built-in oven fixture with either two ovens or one electric oven and one microwave oven.
Wall ovens make it easier to work with large roasting pans and Dutch ovens. A wall oven mounted at the waist, or eye level is easier to use without bending. Steam oven: An oven that cooks food using steam to provide heat is a steam oven. The heat inside the oven turns the water into steam.
An oven is a tool to cook food using heat in a controlled way. Radiant heat is of many types, such as open fire, gas fire, electric heating, and radiation energy. Ovens cook different types of food faster than conventional methods.
Components of Ovens
In this module, we will learn about the components of the oven. Skip to quiz!
List of Components
Ovens are of many types and consist of many components. However, electric and microwave ovens are commonly used today. We will discuss some of the general components which are found in most ovens.
Some of the ovens components are:
Broil element,
Oven rack,
Bake element,
Convection fan,
Convection oven fan blade,
Convection oven Baffle,
Light bulb,
Hidden bake tray,
Oven tube,
Gas ignitor,
Thermostat, and
Oven cavity.
Heating Components
The broil element is typically found at the top of the oven cavity and provides direct heat to the top of food for broiling. The heating element works like an electric iron that produces heat when electricity passes through it. The heating element is an insulator that gets heated on the flow of current.
Recall that conductors allow electricity to flow easily but insulators do not. Both conductors and insulators provide resistance to the flow of electricity but in different amounts. A broiler element uses the resistance to produce heat that cooks the food.
For example, when walking on a crowded street, you have to spend more energy trying to dodge all the people and reach somewhere. This makes you spend more energy and your body heats up. Similarly, a material with more resistance heats up as it won't allow electricity to pass easily.
The bake element is the primary heat source for most oven functions. It also consists of a heating element similar to the broil element.
The baking element is generally located at the bottom of the oven. The baking element is also frequently used for the self-cleaning feature in self-cleaning ovens. The bake element heats up the inside cavity of the oven, and the oil splatters and dust are loosened which can be cleaned easily with a clean cloth.
The hidden bake tray is located at the bottom of the oven cavity. The hidden bake tray protects the oven bake element from spills and drips that occur while cooking. It is advised to clean the hidden tray regularly to prevent any foul smell in the oven.
The oven rack holds cookware and bakeware inside the oven and can be moved up or down before cooking. The oven rack is similar to standard racks to keep more stuff within a confined space. The rack will expose the food to the heating element.
The racks will cook the food faster and more evenly. A broken or uneven oven rack can prevent food from cooking properly.
Fan Components
The convection fan circulates warm air around the oven cavity to help promote even cooking. The convection fan is usually found on the back wall of convection ovens. The heating elements are present on the top and bottom of the oven, so the heat needs to be circulated to cook the food evenly.
If the oven has a convection fan, the fan blade is a part of the oven's convection fan. The fan blade helps the fan create airflow throughout the oven. Fan blade helps in circulating the air inside the oven cavity to cook the food evenly.
Convection baffles encase the convection fan, typically located on the rear wall of the oven cavity. The convection fan consists of a blade, and it is needed to protect from any touches and food accumulating in it.
Other Components
The light bulb and assembly provide light inside the oven cavity and are often found on the top side. The bulb is linked to the door as the door opens; the light is switched on and closes when the door is closed. The proximity sensor helps in switching the light on and off.
The oven releases heat and moisture through the vent tube. It is usually found at the top of the oven cavity. When the food is cooked, the moisture present in the food is evaporated due to the heat. So, the vent tube helps the oven to keep it clean and moisture-free.
The gas oven ignitor, which is not found in electric ovens, ignites the oven’s heating burner. It’s typically located inside the oven and near the burner tube at the back.
The thermostat is a device that measures the temperature inside the oven’s cavity. The thermostat is connected to a capillary tube which consists of gas. The gas expands when there is a rise in temperature and is measured by the thermostat until the desired temperature is achieved.
The expanded gas disconnects the contactor pushing the bellow. Then the contactor disconnects the electrical connection stopping the heating element from heating. The cycle is repeated to obtain the required temperature in the oven.
The oven consists of a wide of parts that are useful in operation. Heating elements help in cooking the food. The thermostat is the main component by which the temperature is maintained inside the oven.
Question #1: The oven contains a hollow chamber and provides a means of heating the chamber in a _______ way.
Open
Better
Controlled
Uncontrolled
Scroll down for the answer...
Answer: Controlled
The oven contains a hollow chamber and provides a means of heating the chamber in a controlled way.
Question #2: In ovens, the food is cooked _____ than the conventional methods.
Slower
Delayed
Faster
Equal
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Answer: Faster
In ovens, the food is cooked faster than the conventional methods.
Question #3: Dr. Percy Spencer discovered the heating properties of _______ while studying the magnetron.
Laser light
Air
Light
Microwaves
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Answer: Microwaves
Dr. Percy Spencer discovered the heating properties of microwaves while studying the magnetron.
Question #4: Electric coils are heated using _____ and supplied in the required amount to cook the food.
Radiation energy
Hydro energy
Electrical energy
Wind energy
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Answer: Electrical energy
Electric coils are heated using electrical energy and supplied in the required amount to cook the food. There are many electrical coils available depending on the type of material used, similar to filament bulbs.
Question #5: The art of making food for consumption is:
Cooking
Frying
Baking
Roasting
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Answer: Cooking
Cooking is the art of making food for consumption. Cooking is done in various methods and numerous processes, but some are used regularly for daily consumption.
Question #6: Ovens based on the mountings are: (Select all that apply)
Electric
Wall
Industrial
Countertop
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Answer: Wall
Countertop
Ovens based on the mountings are:
Wall,
Double,
Slide-In,
Countertop,
Drop-In,
Freestanding, and
Drawer type.
Question #7: A built-in oven fixture with either two ovens or one electric oven and one microwave oven is known as:
Drawer
Slide-in oven
Microwave oven
Double oven
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Answer: Double oven
Double oven: A built-in oven fixture with either two ovens or one electric oven and one microwave oven.
Question #8: Oven components are: (Select all that apply)
Bake element
Engine
Convection Fan
Table
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Answer: Bake element
Convection Fan
Ovens components are:
Broil element
Oven rack
Bake element
Convection fan
Convection oven fan blade
Convection oven Baffle
Light bulb
Hidden bake tray
Oven tube
Gas ignitor
Thermostat
Question #9: Broil element converts electrical energy into heat through the process of _____
Conductance
Heating
Resistance
Transfer
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Answer: Resistance
Broil element converts electrical energy into heat through the process of resistance.
Question #10: Bake element is the _____ heat source for most oven functions.
Primary
Unnecessary
Secondary
None of the above.
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Answer: Primary
Bake element is the primary heat source for most oven functions.
Question #11: Convection fan helps to circulate the warm air and to cook the food _____
Partially
Evenly
At required places
One side
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Answer: Evenly
Convection fan helps to circulate the warm air and to cook the food evenly.
Question #12: The light bulb assembly turns off the light when the door is ______
Partially open
Open
Kept in middle
Closed
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Answer: Closed
The light bulb and assembly provide light inside the oven cavity and are often found on the top side. The light bulb assembly turns off the light when the door is closed.
Question #13: The thermostat is connected to a capillary tube which consists of ____.
Air
Water
Gas
Refrigerant
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Answer: Gas
The thermostat is connected to a capillary tube which consists of gas.