brandon0350
New member
i have 2 ocean runner 2700s. what is the best way to make venturis for them?
ocean runner venturi
- Thread starter brandon0350
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brandon0350
New member
what is a proberly designed one? it has to be water tight. its going to be external
Adam
New member
Hi all,
You can get ASM venturis (same as euroreef) from www.customaquatic.com as replacement parts. They are about $15.
Adam
You can get ASM venturis (same as euroreef) from www.customaquatic.com as replacement parts. They are about $15.
Adam
brandon0350
New member
the connection on a or is 3/4" male threaded. the sedra venturis are slip
Horace
New member
Brandon, you dont attach the venturi to the pump... buy a male adapter that will screw into the pump and has a slip on the other side so that the venturi will slip into it. Thats how pretty much all pumps are designed. Good luck!
You can also get the venturis for the H&S skimmers from www.finsreef.com for about the same cost as the sedra. Couldnt tell you which one is better but my bet is on the H&S.
You can also get the venturis for the H&S skimmers from www.finsreef.com for about the same cost as the sedra. Couldnt tell you which one is better but my bet is on the H&S.
huig
New member
well the problem with venturies is that you need the right size for a certain pump but when you change head the venturie needs to be adjusted to this change. (skimmer body tall or short)
eg I made a recirculating (OR3500) skimmer and the venturie I took worked well up to 70 cm and above 70 cm no air was taken in anymore. you can get around this by:
1- choosing the proper size venturie (you need to test several ones for a given height)
2- a venturie which is a bit too small and using a valve on the airintake
3- using an adjustable venturie
Horace
do you have any proof that adjustable venturies cause turbulence and if so does the turbulence affect the ability to draw in air and chop it up?
eg I made a recirculating (OR3500) skimmer and the venturie I took worked well up to 70 cm and above 70 cm no air was taken in anymore. you can get around this by:
1- choosing the proper size venturie (you need to test several ones for a given height)
2- a venturie which is a bit too small and using a valve on the airintake
3- using an adjustable venturie
Horace
do you have any proof that adjustable venturies cause turbulence and if so does the turbulence affect the ability to draw in air and chop it up?
hahnmeister
In Memoriam
A valve on the intake is actually a very nice way to do it. It makes them very easy to fine-tune. I have two of them set up like that and they run fine. There might be some turbulence, but that doesnt have much anything to do with it...its creating a suction...thats all. The nice thing about a valve is that you can tweak the skimmer intake to get the most air possible...a fixed venturi doesnt allow this. Tweaking is needed because depending on how you hook up an OR pump, its venturi should change as well to reflect the back-pressure placed on the pump with regards to air and water. If you are worried about 'turbulence', just mount the valve farther away from the pump intake and air inlet...but its not really an issue. Its all about pressure manipulation...thats all.
landragon
Premium Member
I SO agree with you Horace.
Edit : and heres why. I have used both fixed and adjustable, and allthough they each have characteritics discussed here that they are named for, his comment that a properly designed one will outprform an adjustable (my words) is true. There will be a large amount of turbulence created at the air water interface of all the adj. designs I have seen, as they require the air intake tube to cross the water flow inside the water intake tube.
Also, the H&S venturi is so much better than the asm, euro, octopus, OR, etc..... On all of the pumps used in those systems too.
hahnmeister
In Memoriam
The venturi needs to be designed for the right pump though. Putting an ASM venturi on a OR might not give the best output...if too large, then less air will be brought in...if too small...then too much air can cause the overall perormance of the skimmer to choke.
I have to disagree with you guys on the valve thing causing turbulence. Since when does turbulence effect the intake of the pump??? Think about it...when it gets to the pump's intake, the whole thing is TURBULENCE. The impellers and needlewheels purpose is to cause turbulence and centrifugal force to pump the water & air out. As far as what goes on before the pump's intake, its just pressure manipulation. If the water valve is closed some, the air intake will go up some (to a point of course). Its that simple. If turbulence is still a concern, you can always mount the water valve farther away from the air intake/pump intake so that the water can regain uniform flow before getting to the air intake or pump intake. There are certain right & wrong ways to do it, but the end result from an adjustable intake on an asperating skimmer is uaually much better than a ready-made one. The ability to manipulate the intake pressures of both air and water seperately to match the pressure dynamics of each unique skimmer you attach it to is very useful.
Back when Spazz was coming up with the Dart NW, I did suggest something that might have been the best of both worlds...an asperating intake with a bypass loop...much like an industrial flow eductor.
On a true venturi...I couldnt agree with you more... the sloped parts of a good venturi eductor, like a mazzei, will aid in the water flow and provide a greater drop in pressure at the air intake. This idea only slightly applies to asperating, because the intakes are on the inlet side of the pump, not outlet...and so even if there is some turbulence, it is easily overcome by the ability to tune the intake anyways.
I have to disagree with you guys on the valve thing causing turbulence. Since when does turbulence effect the intake of the pump??? Think about it...when it gets to the pump's intake, the whole thing is TURBULENCE. The impellers and needlewheels purpose is to cause turbulence and centrifugal force to pump the water & air out. As far as what goes on before the pump's intake, its just pressure manipulation. If the water valve is closed some, the air intake will go up some (to a point of course). Its that simple. If turbulence is still a concern, you can always mount the water valve farther away from the air intake/pump intake so that the water can regain uniform flow before getting to the air intake or pump intake. There are certain right & wrong ways to do it, but the end result from an adjustable intake on an asperating skimmer is uaually much better than a ready-made one. The ability to manipulate the intake pressures of both air and water seperately to match the pressure dynamics of each unique skimmer you attach it to is very useful.
Back when Spazz was coming up with the Dart NW, I did suggest something that might have been the best of both worlds...an asperating intake with a bypass loop...much like an industrial flow eductor.
On a true venturi...I couldnt agree with you more... the sloped parts of a good venturi eductor, like a mazzei, will aid in the water flow and provide a greater drop in pressure at the air intake. This idea only slightly applies to asperating, because the intakes are on the inlet side of the pump, not outlet...and so even if there is some turbulence, it is easily overcome by the ability to tune the intake anyways.
Horace
New member
Guys, here is what you can do for a venturi if you want to build your own. Take the intake tube and then find the next smaller size pipe. For example, a small cross section of 1/2" PVC will fit inside a piece of 3/4" if you make a small slit in the 1/2" chunk so that you can compress it slightly. Drill a hole through both of the pieces after you insert the 1/2" inside the 3/4" where the air hose will be inserted. You can use a dremel to enlarge the opening if you need to until you get the right amount of suction. That is the easiest way to make a correctly designed venturi w/out using a valve. I have seen other designs that are adjustable w/out a valve, but I am not convinced they are any better. I have yet to have the time to actually test it out though. Now that I have a air meter, I can do some more testing but frankly, now that I have an aquabee that came w/ a venturi I will likely just use it and call it a day. Perhaps I will try some different designs on my older DIY skimmer that has a GX2400 that doesnt have a factor venturi, but right now with the venturi I have on it that I built has it pulling 10 SCFH which isnt bad for that pump.
hahnmeister
In Memoriam
Heyyy horace...thats my secret for building venturis!!! I use clear flexible hose as the reducer though. You can use a countersink bit to give its intake and outlet a slight slope, and then you can slip the air line right through it, and the rubbery hose holds it in place. Either way works fine in the end, I just find that the clear tubing is easier to work with since very few PVC pipes actually fit inside each other w/o heavy modification...I tried that too.
BeanAnimal
Premium Member
I have heated a piece of 1" thinwall pvc and stretched it several times to produce a ~1/2" neck with a steeply sloped input (about 30 degrees) and a gradual output cone (about 5 degress).
Because it is 1" pvc, it will fit inside 1" pvc fittings (a bulkhead on one end and a union on the other). This makes it's oveall length somewhat shorter than the kent or mazzie venturis but still yields the same optimized shape.
Perfect? NO... but certainly much better than a washer (orifice) based or valved setup. The lenght is a bit longer than the replacement units sold for ASMs H&S etc and should therefore offer a but less resistance to flow by keeping it more laminar (for the same size pipe reduction).
Bean
Because it is 1" pvc, it will fit inside 1" pvc fittings (a bulkhead on one end and a union on the other). This makes it's oveall length somewhat shorter than the kent or mazzie venturis but still yields the same optimized shape.
Perfect? NO... but certainly much better than a washer (orifice) based or valved setup. The lenght is a bit longer than the replacement units sold for ASMs H&S etc and should therefore offer a but less resistance to flow by keeping it more laminar (for the same size pipe reduction).
Bean
Horace
New member
There was a guy on a different forum who had a different idea as well. He took a section of PVC and filled it with some sort of epoxy and then used a step drill bit (cone shaped) and drilled in from both sides so that the bit met roughly in the center of the pipe. This creates a cone shaped enterence/exit and he claimed that it incresed the suction of the venturi dramatically.
You can also make one on a lathe like this if you have solid acrylic rod (the preferred way IMO)
You can also make one on a lathe like this if you have solid acrylic rod (the preferred way IMO)
BeanAnimal
Premium Member
I thought of a number of ways to do this. I had considered using a "non stick" delrin or similar material to make a postive mold out of and using it to pour liquid acrylic around, lost wax casting with liquid acrylic and a dozen other things. I figured the heated PVC pipe would get me close enough to determine if it is worth the effort.
I am glueing up my unit now... but will not be able to test it until my aquatic eco order arrives... they have been VERY SLOW as of late (slow enough that I will never order from them again).
Bean...
I am glueing up my unit now... but will not be able to test it until my aquatic eco order arrives... they have been VERY SLOW as of late (slow enough that I will never order from them again).
Bean...
RandyStacyE
New member
This is just a crude drawing and I know that this won't work for you exactly as drawn, but I’ve measured the venturi that came with a Gen X 2400 and the ID of the middle of the venturi is almost exactly the same ID of ½†SCH 40 PVC.
Knowing this, it wouldn’t be hard at all to make an excellent venturi from PVC slip fittings.
Knowing this, it wouldn’t be hard at all to make an excellent venturi from PVC slip fittings.
BeanAnimal
Premium Member
Randy the problem is turbulance. It severely reduces the efficiency of the venturi. What you have drawn is no better than a simple washer acting as an orifice (it is worse because of the length of the narrow tube acutally). There will be severe turbulance on the input side as the water backs up against the narrow orifice. The flow through the narrow section will be very non laminar and thus slower than it should be. Upon exit in the larger area the middle portion of the stream will puish ahead and backwards eddie currents will swirl around the right angle area. This will in effect slow the water through the narrow section be creating extra resistance 
Maybe with some creative use of plumber putty and a stick you could at least make the transitions smooth.
The input side should be somewhere between a 20* and 35* angle and the exit somehwere between 5* and 10* for smooth transistion. This of course depends on the velocity and pressure of the fluid and where the engineering comes in.
Maybe with some creative use of plumber putty and a stick you could at least make the transitions smooth.
The input side should be somewhere between a 20* and 35* angle and the exit somehwere between 5* and 10* for smooth transistion. This of course depends on the velocity and pressure of the fluid and where the engineering comes in.
BeanAnimal
Premium Member
Here is a basic illustration of the flow dynamics. The picture you have shown above would create severe flow separation in the through section as well as the output cone.
