Hi there, friendly researcher here. I like to do research and figure out the best way to save money, comparing prices and quality of products and equiptment involved in one of my favorite hobbies, horticulture. I have come to understand that stuffing any solid tube (PVC pipe) that is the same diameter as your in line fan with activated charcoal (aquarium carbon) and taping pantyhose over each end is just as good as a can filter and a whole lot cheaper. Question 1: is that statement true? Does it really eliminate odor? Question 2: How long should the tube be for a 4 in. vortex filter? After googling how to find the volume enclosed by a cylinder and P.E.M.D.A.S. (It's been awhile since 10th grade Geometry) I've found that I would need approximately .75 of a liter of carbon to fill a three foot length of 4 in. PVC pipe. Question 3: Would that be enough to eliminate odor? Question 4: Would it cause much drag on my fan? And finally Question 5: If I put such a filter on my intake fan, the one that cleans the air before it gets "breathed" by the plants, would it remove any of the carbon dioxide? Sounds silly but it did cross my mind. Thanks to all who can help.
well im looking at this as we speak and on this website it says the carbon fiber filter with the vortex fan eliminate 99% of the odor but im also wondering
I have never built a carbon scrubber so any statement I am about to make is purely my own speculation. First of all I would say that after my time personally and effort it is easy to just go purchase a can filter (or similar) than hassle with building them. I love DIY just not for this object. Now... I would say that if you use a proper amount of the correct carbon and force air over and through it at around .1 seconds contact time overall as it passes then you will achieve smell masking. This is the time listed on all of the can filters for optimum scrubbing in an enclosed space (tent, grow room). If you are scrubbing an entire room you will need to push at least 2-3 times the rated air of a pre-made filter to actually scrub the entire space over and over. From my experience with say tents, I have found that scrubbers that have a larger surface area (within reason) seem to scrub better. Probably more contact area for the air moving through the scrubber. The last one I had to buy was two years ago and it gets constant 24/7 use as long as plants are growing and they always are. Of course the one I have is a 25 pound carbon filter and they make them the size of human bodies and larger as well. For your DIY it sounds fine. There are many DIY guides here that seem reasonable if you feel like going that route. Then again you can buy a can filter of apx size you listed for around 50 dollars probably. I pay around 80 for a CAN-33 size. Sure you need a flange and all that to hook fan/duct to but that is like 6 dollars and lasts virtually forever being that it is made of steel. I would increase the surface area of your filter and decrease its length personally. By the way you did not say how large of a space you are scrubbing with this filter? That is the most important pre factor in building one. A tiny one will not scrub a huge room or even a bedroom. And yes any length of duct or impedance you put in front of or after a fan will cause "drag". You cannot put a 100 cfm fan on a 100 cfm filter and expect it to perform correctly no matter what you read or have heard. It will not make .1 contact time with the filter it will be to long and not pull enough negative pressure to actually work right. I am sure everyone else here has their own ideas and that is great, so I guess let the flaming begin... I really would take the time to read the other posts on this subject on this forum, there are many and they have already answered most questions you probably will think of. Your best bet since no one knows right now what you are doing is to experiment with your setup and filtering and see what works best in your space. Or put up some measurements of your space and air flow conditions.