Skimmer Calculator

[crazzyreefer]

Re-designing a skimmer and tweaking them took all my math skills, so I made a calculator to engineer one properly from the start, note the dwell time of a bubble is in liquefaction, air water mixture, not timed in the foam area, although a bubble may rise correctly under 120 seconds, It is only Past this bench Mark that you will be able to adhere all organics, and successfully remove them from your systems. If you have any questions, please feel free to ask, No this isn't a simple calc... but skimming isn't a simple process either, just one of the most efficient! you will notice that some of the designs of commercial skimmers falls vary short of even creating foam, this is the dwell time issue. the amount if time the water passes through the skimmer dose little to improve the removal of organics, remember there is more than one, its sort of like eating, you dip your spoon in in your bowl, but just prior you spill it on your lap, and each bit is repeated, you may have tasted the soup, but your still vary hungry, but with a still hand you can have a spoon filled to the brim each time..... this is proper skimming!.... enjoy the calc and let me know if you find any bugs, and how your skimmer measures up!

Here Is the link its in excel
http://www.savefile.com/files.php?fid=4657033

 

[shallowreef]

Very impressive!

 

[crazzyreefer]

a lot of the thanks goes to mojo reef, he gave me a pair of air stones and I began my quest for a proper design, coupled with and escobar rules and this publish work I attached, I was able to find all the equations, between the two. I'm a bit ADD, so if every thing is jumbled, and not correctly organized...well you will know why...

It is helpful to know your CFM input, although I dont believe most people will get close to the 13% ratio, a few on this board has and this is a large factor.
also note at tiring to saturate the water, you will have to reduce intake of water, or increase CFM and at this point co-current skimming and counter current skimming has vary little differences to dwell times, its only when you increase the flow, does the two really separate the differences of dwell time. we have tested in my shop/company many theories of increasing dwell time, and only a few really work. Most skimmers actually are organic strippers and not organic skimmers. The calculator will work for industrial size systems as well as nano tanks.

http://www.seas.ucla.edu/stenstro/NewBubble.pdf

Nicholas Oberzire

 

[mojoreef]

Thank God!!!!!!!!!!!!! I was getting so tired of having to do the math for folks.. Good on you Nicholas!!


Mike

 

[crazzyreefer]

I will be testing this soon enough, it named until a better word, a Convection Skimmer, the object was to suspend the bubbles for at least 120 seconds, and make the unit fit in a standard cabinet, which this does. its not counter current, although it does run that way it more of a water treadmill

 

[Tiny Giants]

Crazzyreefer

I found a math error on your sheet.

Cell A18 (bubble rise) is an addition of H12 and I7. You need to convert I7 from GPS to inches cubed per second for the value to be true.

The same is true for D18 (bubble rise counter current).

Cell G7 (water cubic feet per hour) is calculated by F7*G7, but they are not in the same units. You need to convert to a common unit, either inches cubed, feet cubed or gallons. Once in a common unit, F7*G7 would yield a true value in whatever unit you use.

Good Luck
Dale

 

[Tiny Giants]

I have a question on the plate design.

I believe the formula you and I discussed for calculating bubble rise to be a fairly accurate model (bubble rise - water velocity) = corrected bubble rise rate. However I do not believe it will work in horizontal flow (plates). The reason is that the bubble rise is acting tangently to the water flow. In a verticle skimmer the bubble rise is either going with or against the flow. So water velocity is either and addition or subtraction from the formula.

Do you think that is fair assumption on the plate design effect on bubble rise?

Dale

 

[crazzyreefer]

I have bubble rise in height ? cu ft per hr of recirc and replacement warer, Ill try to make it do both so it will have an error checker built inm will also change bubble rise rate to 1.8 and make it wasier to figure out...lol


Thanks,,

Nicholas

 

[Tiny Giants]

Your cubic feet of water recirc calc is wrong. Your multiplying cubic inches X Gallons per hour and getting cubic feet per hour as the answer.

In the bubble rise you are adding/subtracting inches per second +/- gallons per second and getting inches per second (velocity).

To me. the formulas appear right, they are just using incompatible units. Throw in a conversion formula, and it is all good. But maybe I just do not understand what you are measuring.

Good Luck
Dale

 

[crazzyreefer]

Im working on a newer version, its simpler, actually the old one works but converts for special reasons

 

[Tiny Giants]

Good Luck.

The more I play with the numbers, the more Snailmans Skimmers work.

Dale

 

[crazzyreefer]

yes but did it work prior to recirulating the flow?

 

[Tiny Giants]

Not on paper it doesn't. We will see what I get in reality. Physicaly his design is exactly what my tank models out to. The funny thing, is that I planned to do this in a 8" design. This calculator shows how that would have thrown off my numbers.

Dale

 

[wave98]

I will be testing this soon enough, it named until a better word, a Convection Skimmer, the object was to suspend the bubbles for at least 120 seconds, and make the unit fit in a standard cabinet, which this does. its not counter current, although it does run that way it more of a water treadmill

Crazyreefer, It appears that your design here would reduce turbulence in the "bubble chamber" to a minimum. This is one of Escobals criteria for effeciency. Is that one of your design objectives here?

Also, it looks like you are "catching" the swirling input water with a pair of "scooper-plates" under the input, and then out to the "vertical rise chamber" ( water only ). Am I seeing this correctly.

This is a very promising looking design. I'm no expert by any means, but I have been following a number of skimmer threads for quite some time, and this one seems like the best I've seen so far.

Nice work!!! > Wave98

 

[crazzyreefer]

you want the bubbles to rise without turbulence, although I dont agree with all his rules, but this one is proven,,,others of his rules are absent of merit, and its sad to say a published work is so flawed, but I still have books that have SS framed tanks....and his work isn't out dated, just not totally correct. I guess I think like my one year old son... round peg square hole... knock it in with the square peg...

one of the difficulties is that a clean air bubble travels at 3cm per min, and a bubble that has collected material travels at 2cm per second or under, this is the largest problem, due to the fact that the last thing you want is to suck the bubbles that have collected metals and allow only clean bubbles to reach the foam area... this is how most skimmers presently work...

as for the design, a motor attached to a boat propeller set in reverse will cause the water to recirculate gently giving time for the air to collect, the 120 second rule is also so the bubble doesnt burst in the foam chamber, now I haven't proven anything but my thinking is that it will carry up more metals and organics without depositing them upon bursting in the foam chamber, if so this will do a number of things things, one it will keep your foam chamber cleaner and the skimmer will run for a longer time between maintenance, the foam will be harder to get rid of, it will resemble beach foam, since it reached the 120 stage, it will not break down easily, I have a few remedies for this... next it will ultra clean the water, and strip all trace elements from the water, including phosphates, and become nitrate free, will test with a Hanna meter, corals from this environment will not do well in a uncleaned environment, trading will be limited. feeding the corals will be necessary. carbon my or may not be necessary.

I have made a new calculator, but haven't the time to proof it, its easier to reed and use and more accurate.