One of my most enjoyable experiences this semester
in Che E 101 was the coffee maker lab. For this lab experiment my
partner and I took apart an ordinary household coffee maker. We then completely
examined the process that it goes through to turn water into coffee. We
also studied it to fully understand how everything works through out the
process. We then had to describe this process and draw diagrams of
it. Then we wrote how the 7 principles of Chemical Engineering are
used in the design of the coffee maker. We also had to write a paragraph
about how the coffee maker demonstrates those principals.
The main thing I learned from this lab was how the coffee maker turns water into coffee. The process all starts when water is added into a storage compartment through a large opening. From there the water will flow naturally down a tube that leads to a one way valve. After passing through this valve it will go into an aluminum tube that has the shape of a horseshoe. The water will stop flowing and remain stagnant until a power switch is turned on, until now the only force acting on the process was gravity. Once this switch is turned on and electric power is added the heating element begins to get hot, this heat is transferred to the aluminum tube where the water is. The aluminum tube begins to get hot and this heat is transferred to the water inside. When the water starts heating up its molecule’s begin to move faster. When it has enough heat it changes phase and turns to steam. Now that it is a gas it will rise up through the tube. This occurs because fluids naturally will move to areas of lower pressure. Once the water is at the top of the tube it is collected in a small area above the coffee grounds. It is in this area that the water will begin to cool and condense back into a liquid state. As the water turns to a liquid and settles in the compartment gravity will take over and cause the liquid to flow down a small opening and drip onto the coffee grounds. The still very hot water easily dissolves the grounds into it and forms the solution that is coffee. This solution then flows through a filter due to once again the force of gravity and drips down into a storage area commonly called a coffeepot. This will occur until all of the water has dissolved the coffee grounds and formed a solution. While the coffee remains in the coffeepot it is kept heated by a heating plate that lies on top of the heating coils. There is also a safety feature that I found quite interesting. The feature makes sure that the coils do not over heat. This works by a thermostat connected to the coils. The thermostat has two metal plates inside it that will expand with heat; too much heat causes the circuit to break when the plates expand too much. The circuit will be able to connect again when the plates cool down and contract back
. I found this experience to be beneficial for me for many reasons. One reason was when explaining how the 7 principals of Chemical Engineering are used in its design; I began to really think of just how many aspects of Chemical Engineering are related to the process. During this thought process I really started to understand those seven principles on a stronger level, and was able to see just how important they are to so many things we come in contact with everyday and take for granite. I also was able to see first hand just how much those seven principals affect are society and how important it is that we understand them as Chemical Engineers. Without the knowledge of those principals I am certain that the technological level of today’s society would be many years behind where it currently is, and every ones lives would be much different. I also started thinking about just how valuable Chemical Engineers are to society just for their knowledge of those seven principals alone. This lab helped me build skills for studying and understanding processes. I feel that the lab helped to improve every ones skills as engineers because it caused us to think like engineers. I enjoyed the total experience and feel I have benefited from everything that came with this lab.
Justin St. Germain
12/13/00