Tiny Might skimmer rockin'
- Thread starter smjtkj
- Start date
BeanAnimal
Premium Member
hahn... sorry, but like I said... your a smart guy but you certainly have a tendencey to paint the science on a little thick and get in over your head. My point is that every one of these threads follows the same pattern. What starts out as a nice discussion with relevant science ends up being a contorted mess of every scientific theory that you can squeeze into the conversation. Honestly in 5 threads you have talked about Bernoulli (the whole freakin family). Einstein and the Law of Conservation, molecular weights and attractions, velocities, vectors, friction, buoancy, viscocity, acceleration, deceleration, pressure, and god knows what else. Much of it misused, misplaced or flat out wrong. Of course some of your information has base and some of your ideas are well founded... it just never ends there.
You can't simply take what you know of science and connect all the missing dots into something that sounds good and defend it with more science that sounds good.
Do we really have to start naming family members and friends as peer review references? Can we not just move on? You seem to want to prove to me (everybody) that you know what your talking about. I don't want to disprove you, I just want to avoid the whole headache and get on with the topic.
I have no malice towards you and certainly don't mind talking with you, I actually enjoy your participation most of the time.. as long is the subject is not SCIENCE.
You can't simply take what you know of science and connect all the missing dots into something that sounds good and defend it with more science that sounds good.
Do we really have to start naming family members and friends as peer review references? Can we not just move on? You seem to want to prove to me (everybody) that you know what your talking about. I don't want to disprove you, I just want to avoid the whole headache and get on with the topic.
I have no malice towards you and certainly don't mind talking with you, I actually enjoy your participation most of the time.. as long is the subject is not SCIENCE.
BeanAnimal
Premium Member
Okay... so tomorrows test run will be a small salad bowl with a few MDF disccs placed on top of it to help move the transistion of the dome back towards the 4" riser tube.
I found a link that has some basic info for those who would like to delve a bit deeper into the process (not that I know any more about it than I have read... and the fact that I bent 4 2x2 sheets of acrylic in junior high woodshop... we had a nice oven)
http://www.plasticsmag.com/ta.asp?aid=2260
I found a link that has some basic info for those who would like to delve a bit deeper into the process (not that I know any more about it than I have read... and the fact that I bent 4 2x2 sheets of acrylic in junior high woodshop... we had a nice oven)
http://www.plasticsmag.com/ta.asp?aid=2260
BeanAnimal
Premium Member
Here is a link to a basic rubber hardness explanation
Rubber Hardness
Do you run ozone? How old is the oring? Is it just plain old EPDM or nitrile? The silicone will be harder than the EPDM or nitrile, but will likely not get hard over time.
Rubber Hardness
Do you run ozone? How old is the oring? Is it just plain old EPDM or nitrile? The silicone will be harder than the EPDM or nitrile, but will likely not get hard over time.
spazz
New member
sorry buddy you are assuming wrong. ha ha ha ha
my cnc can mill steel, stone, and alum. but it will only cut plastic and wood with it. its not heavy duty enough to mill aluminum in my opinion. i tried it once and thought the router head was going to explode from all the nasty noise that was comming from it.
there is a place in texas that im going to call and see if they have any bonded heat sinks they make in a stock size that would work for our needs. the company specializes in heat sinks so they should be able to help. this would also be good for any pump on your tank that was adding too much heat to the system. i know i have a couple of iswaki pumps that run pretty hot.
if we can get it thin enough to bend around the motors and epoxy them into place. then we just have to add a fan to it and you have one cool looking motor. pun intended.
BeanAnimal
Premium Member
Yes, thin enough to bend would be great.
As I mentioned, I also found a company that makes an injection moldable heatsink material (I looked at this as a business venture, but did not persue it due to the low revenue for the time and cost involved).
Let me know what you come up with. In the meantime I am still waiting to hear if my buddy has the time to cast a few of these in his little DIY foundry.
I guess I should mention that I have built a few prototypes using thin aluminum and thermal epoxy. The results were not bad, but certainly not good, as my construction and thermal interface to the pump frankly sucked.
As I mentioned, I also found a company that makes an injection moldable heatsink material (I looked at this as a business venture, but did not persue it due to the low revenue for the time and cost involved).
Let me know what you come up with. In the meantime I am still waiting to hear if my buddy has the time to cast a few of these in his little DIY foundry.
I guess I should mention that I have built a few prototypes using thin aluminum and thermal epoxy. The results were not bad, but certainly not good, as my construction and thermal interface to the pump frankly sucked.
tinygiants
New member
What about the lost foam casting process for the heatsinks? Certainly, Spazz can machine the foam positives. The fins would be the hard part. Matching the curve of the motor is easy. Wrap the motor in sandpaper and rub the foam across it. Result = perfect match.
Would a heatsink work in 2 parts? A curved piece to mate to the motor and a fined piece with a flat mateing surface.
Dale
Would a heatsink work in 2 parts? A curved piece to mate to the motor and a fined piece with a flat mateing surface.
Dale
hahnmeister
In Memoriam
heatsinks are best if they are extruded from copper or aluminum.... casts or mixed materials usually have poor heat transfer.
You might look into cutting up larger pieces (or finding the right diameter of pipe to fit over a pump shroud) of starfinned aluminum pipe to use. Much better transfer properties... and rather easy to make.
You might look into cutting up larger pieces (or finding the right diameter of pipe to fit over a pump shroud) of starfinned aluminum pipe to use. Much better transfer properties... and rather easy to make.
spazz
New member
this company is big into heat sinks and they should be able to help us with our problem. this bonded heatsink sounds like it might work if we can get it in a stock size and thin enough to bend. the bottom plate can be as thin as .030 and almost any size. so im thinking about a piece thats as long as the motor and 2/3 the diameter with find that are 1/2"-1" tall.
spazz
New member
o crud! the stupid link didnt get in there. here is the link ot the heat sinks im talking about and a discription of how there made.
http://www.thermaflo.com/bondedfin.shtml
http://www.thermaflo.com/bondedfin.shtml
dgasmd
New member
My reason is simple. I do have the room for a 6' skimmer and actually do have a 6' skimmer. The reason is air to water ratio capacity and turbulence. The ideal water to air ratio is to have 11-13% of the volume filled with air. Even with as much air as I pumping into my skimmer, I am not near 11%. In my perticular skimmer that amounts to about 7g of air!!! However, as I go up in the volume of air, the turbulence increases exponentially making it a limitation. I don't have a dissufer plate or a cone top, but I suspect even with the diffuser plate I would not be able to hit that 11%. With the sequence pumps, one has the ability to process a HUGE amount of air, so I see it limiting to have mostly a tall skimmer with these designs. I would prefer a wide and shorter skimmer because one can disperse a much much bigger volume of air without creating the turbulence you create with a narrow skimmer. You have to remember that by having these needle wheels in a "close loop" fashion one is re-processign the same water over and over, so the assumption of having a tall skimmer to increase contact time being the only way to increase contact time is no longer valid.
I was not aware of any concrete and objective comparision of tall vs wide skimmers, but I would love to see it or read about it. Do you have a link to where this was??
BeanAnimal
Premium Member
dgasmd, contact time as a result of a bubble rising through a column of water is different than "dwell time".
If you read the Escobal text and the other studies, the "contact time" is that between a water molecule and a host bubble. In the recirc design the contact times are just not there. The water may recycle and make contact more than once, but it is not a sustained contact with a bubble.
If you read the Escobal text and the other studies, the "contact time" is that between a water molecule and a host bubble. In the recirc design the contact times are just not there. The water may recycle and make contact more than once, but it is not a sustained contact with a bubble.
BeanAnimal
Premium Member
Well lets look into this.
1) Alloys are used for heatsinks on a regular basis. What in the world do you think aluminum is? It is an alloy in the form we use it, not a pure element. It contains a fair amount of Iron, Silicon and Copper (among many other lesser quantits of metals).
2) Cast heatsinks are very common. VERY COMMON. Cost is a major factor. Needles to say, the thermal capacity between a cast and extruded part is dictated by much more than the base material or process.
3) We are certainly not out to engineer a heatsink to eeek every watt out of our pumps. The idea is for a general design that will remove some heat and help the pump run a bit cooler.
4) MOST COPPER heatsinks are either CAST or BONDED.
So in a nutshell, your statements are not really valid. There may be some truth to the statements (other than the comment about extruded copper), but they just has no bearing here. It is like saying "gold is a better conductor than copper, so you should not use copper for wire, you should look into Gold" The statement has some truth but is useless in most cases... I hope you see the point here.
Back to casting... here are a few notes on cast aluminum and the use of ZINC as an alloy.
Here is a site http://www.cs.unc.edu/~pxfl/papers/heatsink.pdf with some basic information and a little more detail from the same person http://www.cs.unc.edu/~pxfl/papers/efficiency.pdf
Here is a site that has some information on cast heatsinks http://www.kineticdiecasting.com/heatsink.html
and a bit of tech about aluminum http://www.kineticdiecasting.com/tech.html
And a site dedicated to computer heatsinks http://www.heatsink-guide.com/content.php?content=heatsinkinfo-2.shtml
Copper heatsinks cost more (material cost) AND ARE NOT EXTRUDED, THEY ARE DIE CAST!!! Copper is just to hard to machine.
Read that again... copper heatsinks are DIE CAST not EXTRUDED!
Now lets get to the reality.
We need to move a rather small amount of heat that is spread over a fairly large surface. We have a fairly large amount of room for heatsink materiel. Therefore we really don't have a need to seek the BEST heatsink material so that we can maximize the process. All we need to do is a get a basic heatsink that can take some of the heat away a pump that has very poor conductivity to the air. We certainly don't have a 200 degree chip with 5mm of surface that is producing 200W of heat. We can therefore be somewhat lazy in the materials and design department.
I took a soda can, flattened it and cut fins into the edges. Wrapped the thing around my pump and put a fan on it. I was able to pull the pumps internal temperature down almost 1 degrees compared to the fan alone (therm placed in pump housing). My little experiment had NO MASS and the can is plastic coated (or whatever they do to soda cans these days). The contact was poor and I used velcro to strap it on.
So yes copper would be the best choice, but getting custom copper heatsinks for pumps is out of the questions.... Die Casting is something we can not do at home, so that leaves DIY home shop sand casting, DIY aluminum and epoxy laminations or a company like spazz has looked into.
And of course the injection molding that I mentioned.
Anyway...
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BeanAnimal
Premium Member
Might as well continue...
Better heat transfer properties? Hahn the base metal is only part of the equation. As (or more) important is the fin configuration. In one breath you are disqualifying certain metals and processes and in another advocating a piece of starfinned pipe?
Finned pipe comes in many varieties. Most of it that is reasonably priced is certainly not optimized. It certainly is an Alloy designed for strength and corrosion resistance first, not heat transfer.
MOST is BRASS, NICKEL, MILD STEEL or STAINLESS and used in industrial heat exchangers where lenght and surface area can be maximized. Of course there is aluminum ALLOY extrusions out there, some of it has laminated fins as well.
If your concerned about the therm properties of metals, then you should in turn be conerned about the cooling fin arrangement and their capacity to move the heat from the surface of the sink.
But the burning question is where in the world is one going to find Longitudinal Finned Aluminum Pipe that fits the OD of their pump, and does not cost a small fortune!
BeanAnimal
Premium Member
So thats what makes my beer taste funny...
