I have bought 4 fan filters to test, but I have no idea how to do it. I could let each one run for a couple of weeks in my system, but I would rather devise some intricate method to test them, I am an engineering student Any (good) ideas?
What do you want to test? If they're good for filtering or if they allow enough airflow? Case 1: Use each filter for some time and measure the mm of dust acumulated (I loled with this idea) break; Case 2: You'll need a fan and a garden garbage bag (those black plastic ones); the volume of the bag should be printed somewhere, maybe in the package that contains the bag. Measure the time that takes to fill the bag with air, do the same with each filter. I hope I was helpfull.
I read this just before I went to bed last night and, as an engineer myself, had trouble falling to sleep while thinking about it First you need to determine what variables you are testing for. I think the most important quantifiable variables when using a fan filter are (in order of importance): the percentage of dust filtered, air restriction, and noise. Qualitatively, overall look/design, ease of cleaning and ease of installation would be important. Then of course, the price can be used to sort the four filters. I would go about giving each category a score of 0-5, averaging out the qualitative categories, for a total score of 0-20. Testing Testing really should be done with no less than 12 fans and 3 of each filter (so as to average out results), but more reasonably, I would say it could work with 4 fans and 1 of each filter. Measuring the dust would probably be the hardest one to do cheaply, accurately AND quickly. After thinking about it a while, I think the best idea would be to set up a rig that has four fans side by side (or 12 if you are so inclined ) which each have one of the fan filters set up on them. You should also place a board behind them covered with a smooth white material with some "grip" to it (either a paper towel or cloth) to catch any dust that goes through the fan. The only problem here would be the actual measurement of the dust; it may have to be largely qualitative. But a comparison of the dust on the filter to the dust on the backing/fan should at least give you comparative results. Oh and you'll probably either want to wait 6 months or until the fan filter is 100% clogged, whichever comes first. Measuring cloggage could be combined with experiment number two... ...Measuring air restriction. This is really straight forward if you have an air speed meter (aka anemometer). I doubt these are cheap though, but this is SCIENCE! Alternatively, you could do Kenny's idea and see how long it takes the fan to fill up an object of known volume. Of course you have to be careful about leakage around the seal and that when you get close to full volume you aren't causing any pressure issues. This should be measured before you get any dust on the fans, but it might also be interesting to see how air restriction progresses over time (and *might* be a good indicator of filtering effectiveness -- the fan that drops of faster over time will be the one that is clogging up, i.e. filtering dust, faster). Thirdly, noise can be measured with a dB meter (also probably not cheap). Without equipment, one could probably aurally compare the three and give a ranking, but I doubt this would be accurate. Again, it would be interesting to see how this changes over time. The qualitative rankings are pretty straightforward: assign each category a score from 0-5, 0 being non-existent, 5 being perfect. Displaying the data would be the most fun. I would figure out a points/$ ratio and/or display points vs. price. I'm also envisioning an Excel spreadsheet which allows you to assign your own "weight" to each variable (currently they are 1, 1, 1, 1/3, 1/3, 1/3, but what if someone values dust-catching ability as twice as important as noise or airflow?), and recalibrate the graph/ratio. :drool:, sorry, I maybe have gotten a little too excited there. But anyway, you asked for an intricate method, and you got it!
I have that problem sometimes too. Sometimes you find the perfect solution, but it is always gone when you wake up. Dust filtration, air flow, noise and cleaning are the ones I am going for. Engineers make ugly machines, but they always work. Testing Getting FedEX to cough up my packet with the filters was hard enough, I am not ordering more. Regarding the fans, good idea. I will have to buy 4 mainstream 120mm fans though. Xilence red wing maybe? I had this idea too, but I hate waiting. Ofcourse it would give me an excuse not to clean as long as the experiment is running. Fans are 12V, perhaps a overvolting could reduce the waiting. Beeing an engineering student have its perks, 24/7 lab access. I have not seen an anemometer lying around though.....yet We call them P / V schedules, no idea what it stands for. It does give me a final value for each fan, including the weighted areas. I could make a pillar-graph, but those are boring. I could make the pillars of boobs? Indeed I did. Have some rep good sir. This will be fun, I tend to work like this though.
I added the other ones in there depending on your audience. Sometimes it matters what they look like, and obviously if you can't get them on they won't help! I don't know anything about fans, but anything with consistent build quality should be fine. Also you don't want anything *too* loud since you will be running 4 of them 24/7 I'd take any excuse not to clean! The reason I picked 6 months is because I cleaned out my tower after 6 months and it wasn't OMG THAT'S BAD, but it was at least noticeable. The next time I cleaned it out was 13 months later and that time I had quite a bit of dust. It'll just depend on how dusty your testing area is and how quickly the filters work. It could very well be that most of the dust blew through my case before it had time to stick to anything, so there was pretty slow accumulation (I have 5 fans running 24/7 in a pretty good flow configuration). I dunno about overvolting though, you'd have to ask someone who knows how that will affect the fan's lifespan. I'd steer away from it if at all possible. It would be nice to be able to simulate months of testing, but I doubt you'd be able to simulate household dust very well. It's very fine by itself and anything you could get to simulate it would probably be large particles. When I was in school they had some in one of the fluid flow labs. We measured laminar flow by having a large tube STUFFED with straws on one end to induce laminar flow, then on the other end we used the anemometer to measure... something or other. I never really understood but point being, there probably around there somewhere. I don't know what your school is like, but at mine I probably could have found one I could use for a day or two by asking my favorite professor. Never heard of them, but you can't go wrong with graphs. And... boobs? Wooo you broke my rep cherry! I still love Home Improvement. It's one of those rare shows from my childhood that are still funny nowadays. There isn't too much that's dangerous to worry about on this project (*cough* overvolting the fans *cough*), just don't stick your finger into the business end of a spinning fan and you should do alright.
how about a cardboard tube / box behind the fan, and a measured amount of something "dusty" ... i.e. talc, baby powder, whatever ... would be most accurate if each test rig was contained in a larger box or whatever. give each filter / fan combo the same amount of powder on the in side .. and measure how much gets thru to the out side ... would need some sort of graduated cylinder for measuring ... and a preferably non-stick surface to catch the "gets thru" dust. ok i been in the car all day, brain is empty now.
