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Laboratory Exercise: Water Dispenser

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Laboratory Exercise: Water Dispenser
Hello everyone, welcome to the fourth laboratory session. So, today we will be looking at aproduct for this session which is the water dispenser. Most of you know what a water dispenser.Today, what we are going to do is to do an exercise on technical questioning and missionstatement for this product.In the last two classes, you were just looking at the product and preparing parts list and anassembly chart, so now we will move to the next level where we look at for a given product howdo you prepare a mission statement through technical questioning and you learned this technicalquestioning and mission statement in the theory class, so we will try to implement that for thisproduct.But what we do is we will go with the same procedure of product dissection and preparing theparts list and then instead of preparing an assembly chart or assembly structure we will go to thelevel where we try to identify the mission statement for this product, so that is going to be theexercise that you are going to do today.(Refer Slide Time: 1:24)The objectives are understand the functioning of the product and then identify all the parts andsub-assemblies of the product as in the previous case also, so this will be very common in almostall the experiments and then you have to prepare the parts list and assembly chart and once youhave done this, then you need to look at the technical questioning.So, you are assuming that you are going to redesign the product or you are going to make aproduct of this category, you want to know what should be the mission statement for that productand to do that we will do a technical questioning and at the end of the technical questioningbased on the answers that you get you need to prepare the mission statement for re-design of thewater dispenser. This is what is expected from you as an outcome of this lab experiment. Let uslook at the product.(Refer Slide Time: 2:15)The product that you are going to use or going to dissect is the hot and cold-water dispenser.This dispenser has got the feature for dispensing both the hot and cold water. It is made byShriRam Industries and the model is Zentra Aqua 5H3CRF2, so that is the manufacturer’sspecification or the model name.(Refer Slide Time: 2:40)The main function of this product is to store the water and deliver the water both hot and coldwater, so these are the main functions of this product, so the product should have some facility tostore water and the product should have some facility to heat water or to cool water and thendispense the water. You need to have these four functions in the product.We need to see how these four functions are actually put into the product or how the differentparts actually contribute in doing these main functions. Okay, so the procedure is almost thesame as what we did in the earlier experiment also, understand the functions and features of theproduct, remove the fasteners, so you remove the fasteners.First thing, you look at the product and then look at the overall structure of the product andoverall functions of the product and then remove the fasteners, identify the parts and theirfunction. Whenever you remove the fasteners and other parts keep a record of this, pleasenumber the parts and then keep a record of each part that you are removing and the procedure,the way which you are removing it and then prepare the parts list and product structure.So, after all these parts taken out, you prepare the parts list and the product structure and ofcourse you need to re-assemble it, but before re-assembling it, you start doing the technicalquestioning in the class itself with your classmates, your batch mates, your group members, youcan discuss and then prepare the technical questioning and the mission statement, so this is whatactually is expected and all of you know how to do a technical questioning and prepare themission statement, but just to ensure that you remember it, I will explain it also, I will explain itonce again.(Refer Slide Time: 04:32)So, the report to be submitted, so whatever you do at the end of this you need to submit a reportso the report submitted will be as formatted with this, so the first part will be almost the same inthe previous report, product main function, product history.(Refer Slide Time: 04:50)And then we go to the dissection procedure and tools needed, then prepare the parts list and theassembly chart and then go for the technical questioning of the product. Now, since the productis in front of you and you have seen what is there inside the product you can ask the question,what is the problem with the current product, is there a real problem with the current product, soyou can ask yourself, you can ask your friends and then see what is the real problem about.If the problem is with the filling of water or the problem is in the delivery of water or if there is aleakage or efficiency of cooling or heating, so what actually is the problem that you can identifyso that you will be able to pre-design the product, that is the first question you would be asking.Then, you go for what are the expectations and desires for a customer from this product, therewill be some implicit expectations.You are not expecting this to give aerated water or you do not expect this to be used for hotwater for some other purpose it is only for drinking you will be using and cooling also you donot expect this to be too cold or too hot for the human consumption, so these are some of thebasic expectations and you expect that it will be working basically on the using electricity, sothese are the implicit expectations.And then, you start to take the questions like the customer needs requirements and constraints aretruly appropriate, this is based on the problem that you have and the expectations of thecustomer, whether it will be truly appropriate, you have very limited knowledge at this stage, butstill as a group you will be able to answer these questions and then ask the questions whatavenues are for creative design, can you do something creative to make the product a better one.And then, what characteristics, properties must the product have and then what aspects of thedesign task can be quantified, similarly any biases exist with the chosen task and what are thetechnical and technological conflicts in the design. This is an important one, which I will tellyou where the challenges lie in re-designing the product.There may be some technological challenges that you will face, so if you can identify thosechallenges that will be worth, for that you will be able to look at the challenges and thenre-design the product and based on this prepare the mission statement. You know the missionstatement, there is a particular format for the mission statement, so please prepare the missionstatement and submit the report, so this is what is expected from you as an outcome of this labexperiment.I hope you understood this, so you can go to the TA and the TA will help you to open theproduct and understand the parts and the functions and then you do an exercise of technicalquestioning and mission statement. Thank you.(Refer Slide Time: 08:46)Student 1: So, what is this product, any idea?Student 2: Water dispenser.Student1: And can anyone tell me the function of this product?Student2: To dispense hot or cold water.Student1: Right, it has a refrigerator built into it. At your homes you might be havingrefrigerators. Any idea how those things work? So, this also works on the same principle. Thereis hot water and cold water, so cold water works on the refrigeration principle and hot water islike your normal, there is a rod that is heated and the water is heated.So, now start dissecting it, remove the loose parts first and remove the screws here, remove thetaps here and no need to remove this full thing because it is pretty difficult. You can remove thetap by turning it. No, like this.(Refer Slide Time: 09:08)That is like a simple door. So, is thermocol present here, any idea what it’s work is?Student2: Insulating.(Refer Slide Time: 09:19)Student1: Exactly, so basically the cold water is stored here, in this particular chamber and thisthing insulates it, so just remove the thermocol. Okay, anyone heard of a term known asthermostats? You know what they are?Student1: Yes, something like that and anyone knows the working principle of thermostats? Endof the day, you have to somehow break the electricity circuit to stop the heating of water orchilling of water. So, one is for hot water and one is for the cold water.(Refer Slide Time: 10:12)It is soldered there, so it will not come out, just like pull it aside. I will tell you.Student2: (()) (10:15).Student1: No, no, no, I told you this is connected to that particular container whose temperatureyou have to maintain, so it is more of a switch on and off, so if the temperature rises above acertain level it will switch off, if it falls below a certain level it will switch off like for cold water,so like that. As in the strip turns up and down.(Refer Slide Time: 10:39)So, there is a gas like ammonia or there is this gas HCF, so these sorts of gases are used to cool.So now what exactly happens is there is a tubing system, a copper tube which has the gas trap.What happens is the gas goes into the compressor.(Refer Slide Time: 11:27)Now, this is the condenser, so this part, this full part is the condenser. Do anyone of you knowwhat a radiator is?Student2: Radiator radiates heat.Student1: Yes, sort of. So, what happens is suppose you have a hot piece of metal, it will radiateheat, right? So, it will cool down and to increase the amount of heat it is radiating we increasethe surface area. So, also this also acts something like that, what happens is these tubes arecopper tubes, these are hollow from inside.Student2: It is hollow from inside?(Refer Slide Time: 12:03)Student1: Yes, hollow, so the gas coming out of the compressor passes in these tubes okay? Andit radiates heat and these things, these lines of metal, thin wires, these are, basically their functionis to increase the surface area, because imagine just this tube, these tubes, thick tubes and thesethick tubes plus thin tubes. Obviously, the surface area of thick plus thin will be much higher, sothe amount of heat they are radiating will be much higher.So, what happens is as I was telling you the gas that comes from this tube and goes to thecompressor is high pressure and high temperature gas. When it passes through the compressor alot of temperature or heat is radiated from the gas, so here you can assume that the gas is highpressure, but the temperature falls, say low temperature.(Refer Slide Time: 13:00)Okay? Now next comes the evaporation. What it does is it sort of initiates because the gas is ata high pressure here it is in a liquid form because when you compress something it turns toliquid, so this evaporator what it does is it initiates a process in which the liquid gas startschanging into a gaseous form. Okay, now what happens when water evaporates, steam. So, itneeds some energy to evaporate, like converting from liquid form to gaseous form it needs someenergy.(Refer Slide Time: 13:58)So, this is like latent heat, this is something like latent heat. So, what happens is, this gas startsevaporating from a liquid state, now it needs some heat to evaporate, okay? So, these tubes arewound about some chambers, so in our particular case this is that chamber and in case ofrefrigerator, refrigerators are also that chamber and the heat that the gas needs to evaporate ittakes from the chamber. So, now imagine if water is kept here and this gas is extracting heat,what will happen?Student2: Cool down.Student1: Exactly, so that is the basic principle, it becomes cold and this same cycle, the sametubes they first wound this particular container then go into the refrigerator, wound there andonce here this thing is like low pressure and low temperature, like after it passes the chamber it islow pressure and low temperature, then it again goes to the compressor, turns to high pressurehigh, the cycle continues, so this is the basic refrigeration cycle and this is for cooling. Okay,now I want you guys to look at the components inside and draw a diagram like how the coppertubes are traveling, you will be able to figure it out.(Refer Slide Time: 15:11)So, for example, this is one component of how the copper tube is connected to that component,then from that component where the copper tubes are going. So, just draw a diagram if you can.So, the first compressor, this part is the compressor, this black part.(Refer Slide Time: 15:23)Now, you see this tube, this is coming from the compressor, just take a look inside it, this thinggoes this is the same thing only. This thing goes, this is the condenser, so as you see here,compressor, then condenser. Then comes up this part, these two parts the spring and thisparticular component they are the evaporator, so after condensing the evaporator.Student2: This is the condenser?(Refer Slide Time: 16:28)Student1: Yes, this full black part is the condenser, so this is the evaporator. Now, see this thintube it goes here, it winds here. Then, yes, this is our cooling chamber, then it goes here down,this is the tube, it goes inside so our refrigerator is our second cooling chamber, from therefrigerator it comes back to the compressor, so this is the cycle. So, this is how the cooling isdone.(Refer Slide Time: 16:35)Now, coming to hot water. Now, this particular chamber, have a look at this. So, that is ourchamber where hot water is stored, so hot water what happens is it just works on a simpleprinciple, like how your geysers work, there will be a rod which heat, that is the heating element,when electricity passes, it heats up, it heats the surrounding water and then shuts down, so samething this chamber stores water and it has a heating element in it, so that is the place where hotwater is stored.(Refer Slide Time: 17:13)Now, if you look, have a look. Take a look at this particular hole. This thing it passes down, thishole passes in this particular tube just see if you can see it, okay? And it comes out from thecold-water side. Because I told you that cold water is stored there. So, it goes down and comesout from the cold water, that is our cold water.Secondly, you will see this particular tube also, there are two tubes, one tube, second tube, thistube goes to the hot water chamber. So, your hot water is stored there and from the hot waterthere will be one more tube that comes out from the hot water chamber. What it does is whenyou pour water from above there is some water that will go inside this particular hole and there issome water that will be stored here, so if you see the tubing, the tubing is not covering the entirecontainer, it is just covering this particular part.So, it sort of separates hot water and cold water, there will be some loss of efficiency because atsurface hot water, like normal water and cold water is there, but like it is the simple way toseparate the two chambers and increase the efficiency.Student1: These strips?Student2: This.Student1: To the cooling chamber, this thing travels down, it goes to the second thing, and fromthe second thing it comes back again to the compressor.(Refer Slide Time: 18:43)So, these wires are basically attached to this LED in the front, say your water reaches theparticular temperature and this thing turns off, that is it does not heat anymore, then this red lightwill turn on to show you that heated water is ready, same is the case with the cooling chamber,so this thing is more of a digital thing, just on and off, for that changing thing, there is a dial andyou have these things, say example, a refrigerator you can set how much the temperature is, sothose are different types of thermostats.(Refer Slide Time: 19:30)One thing you can do is increasing thickness will be difficult but you can change this particulardistance, back panel. Yes, so this is the metal strip, it is used to mount the condenser, just mountthis thing first, then from outside just screw it in. This is the condenser; part is the thermostat. Ifit is difficult, you can remove this particular part.(Refer Slide Time: 20:04)And this is the top panel, so we will fix this thing next.(Refer Slide Time: 20:12)These are the taps used to dispense water. We will fix them next.(Refer Slide Time: 20:22)These are thermocol pieces used to insulate the cold-water chamber.(Refer Slide Time: 20:36)This is the water collector; this is used to collect the dripping water.(Refer Slide Time: 20:44)This is a shelf, it is used in the refrigerator to accommodate more items, so it goes in here.(Refer Slide Time: 21:03)This is the water filter, it does not allow waste to go into the water collector, this part, so it goeslike this.This is a water guide; it is used to guide the water from the can to the chamber.