atlasstone

Benchtop Test Tank

144 posts in this topic

Frustrating isn't it--been here done some of it --for what it's worth here are some alternatives,  although I still feel the prop is the way to go.

 

Instead of drinking straws (for reducing turbulance) maybe use short lengths of 1" PVC pipe stacked OR irrigation hose which is very thin walled, just glue them togeather  - OOOOOOOOOr maybe ice cube trays.

The retired fireman in me says look up 'Relay Pumping'-- this is a poor man's three stage pump:

Run the outlet from the first pump into the eye of the second pump which in theory will double the flow, then into a third pump and it will double again

( 1200 ---> 2400-----> 4800 GPH) -Keeping in mind you will need to increase the outlet line of the second and third pump to allow for the extra flow into the next, otherwise I think you will only get an increase in water pressure.

 

For a rough 'speed indicator', buy a cheap digital bicycle speedo (with the magnetic wheel pickup-- pinch one off your kids bike), find a small wheel and calibrate the speedo to the wheel diameter, add some paddles to the wheel (OR very small model boat prop is what I used @ about 1" dia) and away you go. I made one of these for my boat years back and once 'calibrated' properly they are pretty accurate.

Even if this is not accurate enough, any increases you get will be realtive to your initial reading.

Hope this helps and doesn't throw you off track :?  :wink: .

Pete

Edited by hazmail

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Great thread and great progress made. So glad the Wchilton was right and there was more to it than just the pump rate.

 

Have you tried a lure in there yet, to see if you are reaching the minimum flow to start the lure action?

 

Keep up the good work :)

 

Dave

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Friction slowing things down would be my concern as well.  If you already have the material and don't mind spending the time it's worth a shot,

 

 With no "head" or vertical lift, you could be getting much more then the 1200 +/- GPM claimed.

 

wchilton, I do already have the material. So I am going to give it a shot.

 

 Also, I think you are right about the increasing velocity/pump capacity effect caused by the no head and the retained momentum of the recirculating water. 

 

This thread is getting more and more interesting. Thanks everyone for all the input and a very big Thank You to Atlasstone for starting it.

John

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I'll give it a shot and see what happens.  I'm sure others that are more physics savy can confirm this, but I don't think the object itself really matters.

For the purpose of testing, I chose a round shape so that the distance traveled would be as accurate as posiible regardless of if it spun.  If it were a rectangle and the object spun 90 degrees in the middle of the measurement, it would throw the calculations off because I would need to compensate for the added length at the end... and I'm just too lazy and not that smart.

If the object is unhindered from moving in anyway, then I think any object that is suspended in, or floating on the water column would move the same speed as the current. Much like a boat with a drift sock. If there is no wind to move the boat faster than the current, then the drift sock is useless because it will move at the same rate as the boat which is identical to the speed of the current. Only when another force acts against it will there be a change.

 

Here is a link that explains it a little better:

http://wiki.answers.com/Q/How_does_mass_affect_speed

 

I think the question I need to answer by suspending the object is whether the current under the surface is the same speed as the current at the surface.

 

Am I off base on this?

 

 

Might want to take a look at an orange for testing.

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Have you tried a lure in there yet, to see if you are reaching the minimum flow to start the lure action?

I have on mine.  There is a video link on the first post.  I neglected to embed it so it's kind of hidden.  The action will start at fairly low speeds but I really wanted to test my lures to see if they 'lay down' when cranked fast so that was the point of the exercise for me.

 

 

Thanks everyone for all the input and a very big Thank You to Atlasstone for starting it.

No problem!  I'm glad to see it taking off and other design ideas floating around.  It looks like you have a really clean design going so far JBlaze.  I'm anxious to see how it progresses.

 

Does anyone have any thoughts on whether or not an anemometer would work for speed testing?  I suppose if it's all relative, then it would be a cheap and consistent device for use to comapre speeds with.

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Up date on the Test Tank.

 

This is what I am using to make my Baffles

 

2013-02-27_16-15-10_299.jpg

 

This baffle is almost finished and ready to install. There are ninty-five of the 3/4 inch strips in it for a total of 4750 channels/holes for the water to flow through. I have to make another one for the other end. I hope to finish this thing this week and find out if this was a good idea or not. What do you fellows think. Will it have enough flow to be able to test lures.

 

P3030067.jpg

 

I some how deleted the pic of the tank in the other post, Here it is again.

 

P2250065.jpg

Edited by JBlaze

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I like what I see, and I think it just might work.  I also think Vodkaman is right, try it with one first.

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JB - try it with just one baffle first, may not need the second.

 

Dave

Thanks Dave, I will give that a try. I had not even considered that. My thoughts were that the three intakes at the end of the tank would somehow distort the even flowing of the water.

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Don’t know that anyone wants to see this or not but at least  you will know one idea not to give a shot or maybe you might have an idea that would make it work. My first attempt at making a test tank was a failure. In this clip, I am filling the tank and turning on the pump for the first time.  As Dave suggested, I only used the one baffle for the initial testing.



th_P3040069.jpg



In this second clip, the pump is running but there is nothing happening.



th_P3040070.jpg


 

In this third clip, I open up the pump and find that it was airlocked.



th_P3040071.jpg



 



In this clip, I have removed the baffle to see if there was any flow without it. As I lifted the baffle out of the tank, I noticed that it was very heavy. With the pump running, there was  water flowing out of the pumps three discharge holes but I was still getting little to no water flow across the tank.



 

th_P3040072.jpg
 

 



In this final clip you will see that the baffle is just full of water for some reason that I don’t comprehend/understand. It retained all the water in the channels even though I had set it down. Watch what happens when I tap it on the ground. After seeing that, I realize that water is not going to go through this baffle unless it is under some kind of pressure. So,its back to the drawing board.

Atlasstone, I meant to say your name in this clip instead of Anglinarcher..  



th_P3040073.jpg



Thanks to all for your encouragement and enthusiasm with this little project. Be assured that I will be giving it another shot.



John

Edited by JBlaze

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John –. Sorry it did not work for you, but that pump is woefully under powered for the job. I guess the flow calculations were good then.

 

If the tank was only half filled and split down the middle, pump one side, lure test on the other, you would get 4x the flow, but still not enough to  drive a crank. The baffle, as you surmised, is going to restrict some of the flow too.

 

I guess it is back to the drawing board, but the first job will be to find a more powerful pump.

 

Dave



 

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Yes my  friend,  the math was good. But, there are more ways than one to skin a cat. I am hard headed and stubborn. I will be giving this another shot.

I did learn a lot through this project about water flow, laminar flow, friction of liquids in a pipe. All by reading about the things that were posted by others who were interested in making a test tank. If I didn't gain anything other than that, at least I am a little smarter than I was  :nuhuh: Hopefully someone will come up with an idea that works. I am thinking it will be similar in its design to the one that Atlasstone posted. 

John

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Something to consider is gutter guards the ones with the holes and screen, they look like 1/4" holes but are 4" wide. You can put two together and see if that will help. Just my :twocents:  :twocents: , I will be making something this summer.

Wayne

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Ugh... I was really hoping that would work out, but you did get results so that helps. 

 

I'm really regreting not getting any pictures or video of my first few designs. I'm wondering if the laminar flow idea in combination with an oval tube design might work.

 

I took another look at the laminar flow videos and it seems that the straws stabilize the flow, but it's the pressure in the cylider pushing through the hole in the end that actually causes the current.  All of the designs I found have a round hole in the end, but I'm wondering if (for our purposes) the end could be shaped like a rectangle and still take advantage of the layered water column. 

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Ugh... I was really hoping that would work out, but you did get results so that helps. 

 

I'm really regreting not getting any pictures or video of my first few designs. I'm wondering if the laminar flow idea in combination with an oval tube design might work.

 

I took another look at the laminar flow videos and it seems that the straws stabilize the flow, but it's the pressure in the cylider pushing through the hole in the end that actually causes the current.  All of the designs I found have a round hole in the end, but I'm wondering if (for our purposes) the end could be shaped like a rectangle and still take advantage of the layered water column. 

 

So am I, just the weight of the incoming water may have put a little pressure on the baffle but it was not enough to force the water through. The water actually rose behind the baffle and flowed over the top of it.  I thought that would create some surface current but I could not see or find it.

What you said about pressure in a cylinder, I was lying awake last night thinking about that same thing. Maybe making an open faced box with the baffle sealed to the open side and the outlet of the pump plumbed to the box on the side or back of it. this should force the water to come through the baffle holes in small streams.

I have an auxiliary live well aerator installed in my live-well. It has a discharge pipe with 6 holes under its cap the force of the six streams of water shooting out of these six holes is very strong and drives air down into the tank at least a foot. Something along these lines  might be another option but how would you know how many holes to make before the pump would not have any resistance and therefore no pressure?  Maybe it could be plumbed to a couple of or three or four shower heads. Just another thought.

John

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Something to consider is gutter guards the ones with the holes and screen, they look like 1/4" holes but are 4" wide. You can put two together and see if that will help. Just my :twocents:  :twocents: , I will be making something this summer.

Wayne

 

Wayne, will have a look at that. By the nature of it's intended use, I am sure it would not offer resistance to water flow. 

Thanks for the suggestion.  John

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Hey guys, just saw something that even confuses me more.  Starting at about minute 4.03, with the best shot at 4.13, we see another bench test tank.

 

Take a look at this and tell me what you see. 

 



 

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Good find!  I have an email into the company on the Discovery Video.  I'll let you know if i come up with anything.

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Anglinarcher, great video. I have been looking at this for over an hour and am still guessing as to how they are created this flow.  

 

Atlasstone,  I hope you get something back that is useful.

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Dave will love this vortices video :? --

This (flow tank) works because 1200 gpm has to flow faster (to return to the pump) over 1"  depth X 18" wide (= 18 sq") than it would along an open tank of say 18" X18" ( = 324 sq") --To get the same speed in an open tank as across the 1" depth, you would need (in theory) a pump with 18 times the capacity.

 

Which is basically what Dave is saying:

Quote-  "If the tank was only half filled and split down the middle, pump one side, lure test on the other, you would get 4x the flow, but still not enough to drive a crank. The baffle, as you surmised, is going to restrict some of the flow too".

 

Great work here all, glad I did not get down to the prototype phase.

 

Love your work and truly admire your patience..

Pete

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Hazmail - It was very good, demonstrating everything that I have been talking about for five years :)

 

JBlaze - the simplest ideas are always the best. I started drawing something up, adapting the idea to our requirements. I then realized that I was actually drawing AnglinArcher's design except with a stop plate to isolate the inlet and outlet, just like in the video.

 

AnglinArcher - I think your design is as good as it is going to get, so congrats for that.

 

Dave

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