DIY Penductors

fishesRdelicious · #1 12/01/2005, 08:47 PM

does anyone have any plans on how to make one of these?
i know i saw something about them awhile ago but i cant find it.TIA

zapata41 · #2 12/01/2005, 11:01 PM

i did a pair of them a while back, they work pretty good but end the end i ended up buying a pair from kthsales.com the were only like 60$ shipped and look a million times better IMO

Tim

do a search,if you can get it to work, and look for threads started by me, you'll find them in there.

Tim

z_rivers · #3 12/02/2005, 01:48 AM

i tried making them and they worked OK but i took them off because they were unsightly. IMO i would just spend the cash and buy them. they are fairly cheap and it would make up for time and money you would spend to DIY them.

Reefin' Dude · #4 12/02/2005, 03:57 AM

here are mine. i use both. they are relatively cheap anyway. you might want to try the DIY ones to make sure they do what you want them to do. if they are satisfactory then order the real ones. something you can do with the DIY ones that you can not do with the manufactured ones is put an elbow at the end. you can then shoot around corners.

G~

fishesRdelicious · #5 12/02/2005, 02:59 PM

how do they compare to the ones you buy, flow wise

reverendmaynard · #6 12/02/2005, 03:39 PM

Ummm....

What does it do?

fishesRdelicious · #7 12/02/2005, 06:44 PM

no, i know what they do,
i wanted to know how much the diy ones increase the flow

zapata41 · #8 12/02/2005, 09:31 PM

here is a pic of the ones i built, i built a twisted version and a non twisted version.

they had to be placed deeped in the water so not to pull in a vortex then the store bought penductors. flow wise it is hard to tell. they both seem fairly even, but if i had to give one the win i would give it to the store bought ones.
front view

showing the swirling action

back view, notice i added inserts to reduce the opening size to create a larger pressure drop on the front side of the reducer ( seemed to help the most when i was diying prototypes as the models with the reducers puuled in little air)

non twisted version, same as the twisted version, parts wise. equal flow just not as dispersed.

fishesRdelicious · #9 12/02/2005, 09:58 PM

thanks for the replies, i think i will try to make one

rivdog · #10 12/02/2005, 10:00 PM

there is so little pvc left on that piece> what is its function

rivdog · #11 12/02/2005, 10:01 PM

Pic 2

zapata41 · #12 12/02/2005, 11:28 PM

not really seeing what you are talking about in pic two. if it is the reducer then it does play a role in dropping pressures from one side of the penductor to the other

Tim

z_rivers · #13 12/03/2005, 12:04 AM

Quote:

how do they compare to the ones you buy, flow wise

its really hard to say, it all depends on what kind of pump you use. i believe your supposed to use a pressure rated pump rather than just a normal one.

zapata41 · #14 12/03/2005, 12:14 AM

they way i tested the flow, using a mak4 pump on both models, was to place my hand in front of the penductor at various distances throughout the tank. also i use the air suction method where i would use a turkey baster to blow bubbles near the back of the penductor and find out at what distance they would be educted into the penductor. not scientific but effective.

Tim

rivdog · #15 12/03/2005, 12:19 AM

From my understanding(Limited)The eductor/penductor works much like a venturi.. Except, instead of pulling air in, by means of a pressure differential, the eductor pulls in water. The portion after the nozzle helpsto create a vortex??? which increases the volume of h20. You have (from the pic) #2 have pretty much cut away all of the pvc that would create a pressure differential, or even direct the flow. iM not sure which it actually does .

zapata41 · #16 12/03/2005, 12:26 AM

well the pressure differential is not made by the size of the ID of the penducto yet made from the size and lentgh of the ID of the back of the pendcutor vs. the ID of the middle vs. the length and ID of the front of the penductor. there are many variables in lentgh and shape of the fron and back of the penductor that play a big role. i just visioned how a stream of water entering the middle of the penductor would change with a difference in size after the small part, then made it simialar to the store bought ones. i realize that it is a water venturi and works on the same priciples. if you can see how something works in your head and can see how changes to it effect its performance, in your head, then you can design things fairly easy. this has always came quite easy to me, thus making things like this are quite simple.

Tim

rivdog · #17 12/03/2005, 12:35 AM

Ok so, the outer portion of the nozzle can affect volume of flow ----and-- dipersement of flow? Im not sure what the effect of the nozzle is otherwise. If the ID length and Back length are the controlling factors of volme, then the outer nozzle is just a matter of directional preference. ??????

zapata41 · #18 12/03/2005, 12:42 AM

no, the out nozzle is very important to the educting performance. its shape plays a large role in the rate of pressure differential. all three parts of the eductor play a role in educting performance, and to complicate things more, the size of the nozzle in relationship to the flow in gpm and the relationship to the end of the nozzle positioning to the opening of the back of the penductor and to the distance from the end of the nozzle to the middle part of the pendcutor.

so in short, this is really now simply thing to master in design, this i why i feel that my diy verison pulled in air from a greater distance away from the back of the penductor simply because of a few small changes in various sizes and lengths from the store bought versions.

kinda complicated yet very simple

Tim

rivdog · #19 12/03/2005, 12:47 AM

Optimal Performance thru trial and error

zapata41 · #20 12/03/2005, 12:50 AM

well very little trial in real modeling, more of of trial in the head. i actually only spent about 30mintues to makes these and only a little bit more to figure them out in my head, and these were only the second trial to make them, the first ones being that of which i saw on here which simply used a pvc coupling and the eductor body with no id changes.

Tim

zapata41 · #21 12/03/2005, 12:52 AM

and to clear things up as to why i boughtthem when the diy ones worked fine, is, if i can make them adn they work and i like the flow changes then i know i will be happy with spending my hard earned dollars on the same thing that look better to my eye.

Tim

rivdog · #22 12/03/2005, 01:34 AM

i found the thread that was in your head, now I understand, Iwas just visualizing it my own head

zapata41 · #23 12/03/2005, 01:35 AM

i didnt know i had threads in my head, should have been a seamstess. lol j/k

tim

Reefin' Dude · #24 12/03/2005, 04:04 AM

a pressure rated pump is needed. i have tried both the store bought ones and mine on different pumps. my Velocity T3 produces a lot more flow out of both versions than a Mag12. the Mag12 just can not produce the pressure gradient needed to really pull in water around the inner nozzle.

you can cheat a little by changing the inner nozzle diameter for various pumps. the wimpier the pump the larger the inner nozzel should be. this also works in reverse, but we in the hobby are not dealing with pumps that can handle 50psi, the bigger the pump the bigger the nozzle can be. 50psi is listed as the upper range for the store bought eductors.

here is a great page explaining what pumps are recommended for eductors.

G~