Introduction

In modern age, technology is being used to save time, energy. efore civilization, technology wasn’t as developed as it is now and as a result people had to do things manually or by hand. For instance, cooking a food (rice) before civilization required all your attention and focus because if you were not paying attention to what you were doing, the food would burn. But with the invention of the rice cooker, we need to worry less about the food getting burnt because once the rice gets ready, the rice cooker will sense it and will reduce the temptation just to keep it warm. Undoubtedly the rice cooker is a good example about the development and important of technology. It is a combination of cooking and warming mode which helps in keeping the food warm. The purpose of this paper is to provide a technical description of a rice cooker. The technical description will include a breakdown of each component, their function and the science behind the operation.

I like my rice cooker simply because it assists me in making a perfect rice whenever I need it to make one. Rice is a great food for keeping the body healthy, it is source of carbohydrate and energy.  Almost half of the world population consume rice and the rate of consumption of rice in the United states has increased. A rice cooker or rice steamer is an automated kitchen appliance designed to boil or steam rice. It consists of a cooking bowl, power switch, warm light, cook light, power source, a measuring cup, a lid. and a thermostat. The rice cooker had its start with the Japanese army and the Mitsubishi; however, it was not until the Toshiba perfected the electric rice cooker to a simple shut on shut off product in the 1950s that it gained acceptance for home use (Sharon, 2016).

 

Description of a rice cooker and breakdown of each component

As mention in the introduction, a rice cooker is made of a cooking bowl, power source, a measuring cup, a lid and a thermostat. The bowl in a rice cooker is removable, beneath the cooking bowl is a thermostat that control the temperature. There is a spring under the thermostat that tend to push it unto the bowl for a reliable contact with the thermostat. The power source is always connected to the circuit which enable us to put on the rice cooker, without the power cable (source) there is no way the device can be turned on. The measuring cup as the name seem is used to measure the quantity of rice or whatever is it that we plan on cooking. A lid is just basic part of a rice cooker, it is used to cover whatever it is we are cooking. Finally, a thermostat; a thermostat is a device that sense and control the temperature the device ( rice cooker), without the thermostat, the temperature of the rice cooker will either be too much or too small.

                         

Figure 1(a) inner pot                                                         fig 1(b) The lid

                   

 fig 1(c) Thermostat                                                        fig 1(d) power cable

 

How a rice cooker work.

Rice needs two things to evolve from a hard, little grain to big, fluffy morsels — lots of water and lots of heat. For this reason, cooking rice happens in four phases: Sitting in water, Boiling, absorbing water (steaming), and Resting ( Jessika, 2008). The rice cooker as mentioned above consist of a main body, inner pot, heating plate, a thermostat and some buttons. When the rice and water are inserted into the cooking pan (inner pot), the inner pot weight and that of the water and rice exact pressure on the thermostat. The thermostat provides the inner pot with temperature that enable the water to boil. Once the water reaches the boiling point at 100 degree Celsius (212-degree Fahrenheit), the temperature that the thermostat transfers to the inner pot will be steady. In as much the water in the inner pot is still boiling, the rice will absorb all the water in the pot.

After the rice has absorbs all the water, the temperature that is being provided by the thermostat will begin rising, the rice cooker will sense the change in temperature and will either adjust itself to a warm mood or will completely turn off.

Fig 2, Picture of a complete rice cooker (Jessika, 2008)

The mechanism of a rice cooker and heat transfer.

Heat transfer is a field in thermal engineering that deals with the conversion, general use and the transfer of heat from one physical device to another. Rice cookers works by transferring  heat in the means of thermal conduction (shairanda, 2017).  The equation that is governing heat flow along a device is; Q=KADTt/L.

K is the thermal conductivity ( a constant depending on the material, different material has different constant), DT is the difference in temperature ( initial temperature i.e. temperature before the process of cooking the rice and final temperature i.e. temperature after the rice is cooked).  We have different value of K depending on the material, the type of material (metal) used can increase the rate of flow of heat. Most metal transfer heat easily because they are a good conductor of heat example of such metals are aluminum (Al) and copper (cu). Such metal has electrons that moves freely and as a result of free movement, the electron transfer heat from one metal to another quickly.

Figure 3, Graph of an electric rice cooker operation (shairanda, 2017)

 

 

                       

Figure 4(a) power system of a rice cooker    Figure 4(b) power system of a rice cooker with label.

 

 

 Definition and importance of equipment (material) that is in the power system of a rice cooker.

• Thermal fuse; A thermal fuse is a safety device which open and prevent a circuit against overheat. The thermal fuse that is found is the rice cooker after disassembling it helps in preventing the overheating of the rice cooker. It detects the heat cause by either the overflow or lack of temperature supply to the device. The thermal fuse only reacts to excessive temperature and not current, in some cases, the thermal fuse reacts to current only when the excessive current is large enough to cause the thermal fuse itself to heat up and trigger a high temperature.
• AC means alternating current. An alternating current is an electric current periodically reverse its direction.  The rice cooker applies the heat to increase the temperature directly from the alternating electric current from the wall outlet.
• Warming temp switch; The warming temp switch is a switch that if triggered after the all the liquid (water) that is in the pot has been absorbed. After the rice or the food, we are cooking in the rice cooker is finally cooked and the water has been evaporated, the warming temp is going to switch itself to a warming mode (keeping the food warm).
• Off-on switch; as the name implies, it is switch that control the whole device, without this switch, we will not be able to turn on or turn off the rice cooker

 

Reference

• VOLUME 26, ISSUE 2, E5-E6, MARCH 01, 2016. The Rice Cooker and the Renal Diet Sharon Stall, MPH, RD, CSR, CDN
• How Rice Cookers Work BY JESSIKA TOOTHMAN
• Simple Thermodynamics: The Mechanism of a Rice Cooker by shairanda.