Would dual pumps work in one resevoir?

[gone_fishin]

Here's my crude design, don't hurt yourself ROTFL. If pump two is off then the water only enters the resevoir from the bypass tube at the tee in the drawing. Now my question is if pump two were turned on would more water volume be pumped or would pump one still limit the flow?

Pump one is pushing the water and pump two is sucking the water.

Oh I forgot to draw in a shutoff at the overflow for when pump two is turned on.

 

[Ridenow]

Very interesting idea.... I am not sure how well it would work.

I am assuming the pumps would be the same make and model. My initial thought, without any research, is that there would be a slight improvement, but not much. The pumps would share the load and therefore have less wear on them. A pump can only move water at a set rate. I do not think there would be a cumulative effect, I do not think 2 pumps would significantly increase flow.

Again, I stress this is just a first impression and I am not very sure of it.

 

[gone_fishin]

Ok, if you are right then how about this, a second overflow connection between the same overflow line and the exit tube from pump one with two more tees and a shutoff valve in between. Turn the valve (E) on and now when pump two is on it would suck additional water from the same third tube in the resevoir. The tubing would have to change to a higher diameter after the tee from pump one.

Here's another update to my sorry a** crude piece of art.

Edit: take note I forgot to change the arrows for the center tube on this second picture. They should be flowing up and out to the tee above pump one. Not only am I a bad artist but a careless one

 

[Aesik]

I'm failing to see the point of this. What exactly are you trying to accomplish?

 

[gone_fishin]

I've seen a lot of kits come with some really nice aluminum resevoirs but usually the pump is quite small so instead of throwing the pump out maybe you could add another small pump to make up for it.

 

[mcduffiem]

This is exactly how the second Koolance series works. I doubt there is much flow increase. Primarily I believe it's to prevent critical failure in case one pump fails. Of course, how you detect that one pump fail, I'm not sure. Their pumps are incredibly quiet. I guess there might be a noticeable temp increase over the norm.

 

[mcduffiem]

Oops. Should have studied the sketch along with the words.

Actaully the Koolances have the inlet hose connected directly to the "sucking" pump not to the reservoir itself.

 

[Aesik]

Ahh...I see what you're getting at. I was having a hard time justifying why you would use two smaller pumps rather than just one larger one.

One problem you are going to have is that by adding elbows, valves, fittings etc. to the flow path there is going to be a drastic increase in head loss. Valves are especially bad at this and can really reduce flow rate even when wide open.

 

[gone_fishin]

So does the restriction from the valves and tees (one valve and two tees in dual pump mode) overtake the flow gained from the second pump and is there any flow rate gained here, has anyone tried this?

Edit: Should read three tees not two.

 

[Aesik]

That's impossible to calculate without knowing all the exact details or by using trial and error. I can say this though, many valves will cut flow rate by nearly 50%, some even worse.

 

[gone_fishin]

I believe all of the fitting and valve sections of tubing could be done with copper fittings up to where you need barbs and them you would normally use anyway. That should get rid of all restrictions in the tubing from the extra joints. There are non restricting valves with solder joints that would need to be used also.

 

[Aesik]

Just one more question...by the time you to the trouble and expense to rig something like this up, wouldn't it just be better to get a larger pump to begin with?

 

[gone_fishin]

The expense would only be about ten dollars in tubing supplies. The difference in prices of a larger capacity pump and another small one would more than make up for that. The time would be comparable to having to tear out the original pump and replacing it with a larger capacity one, the only added effort would be measuring up and soldering a few joints.
So the big question I would like to know is if performance would be equal to a larger pump or maybe even a little better.
I've seen some complete units selling with lowly 145gph pumps but that's rated at the output nozzle, not after it's set up so performance would be roughly half I would guess.

Edit: This could also be a solution to anyone who wants to add a larger radiator or a second one.

 

[Ichelo351]

one question,
could this type of set up possibly increase the preasure of the water, and also increase the lift of the water?

 

[ezlor]

Why not put the two pumps in parallel rather than series? Put a Y on the input pipe, and run the two branches of the Y into the pump inputs. Then run the pump outputs into the reservoir.

Or you can do the opposite, put both pumps on the output side of the reservoir, and join their outputs with a Y...

 

[gone_fishin]

Good question. I guess it's a matter of which will increase lift better or would they be the same over an equal length of travel.

 

[f155mph]

It will just add more heat to the water. Double pump double heat.

 

[gone_fishin]

Ok, your right on that. Ideally you want to add no extra heat to the loop. So new change, two pumps on top of the resevoir with three tubes going down in the resevoir. Would you gain more with flow is the main concern by having one at the beginning and end of the loop. If so then would it best be used to have a larger radiator or just use the faster flow rate through the block with a standard size radiator?

 

[blckhawk]

I work in a chemical plant so I have some experience with pumps. I am by no means an expert though so take this for what it's worth. As far as flow you would see a slight increase by adding the second pump, but not enough to matter. Your real increase would be in head pressure, but like the flow not enough to really make that much difference. As someone already posted a larger pump would be the better solution. As always if you already have all the stuff,Try it! What can it hurt. Hope this helps

blckhawk

 

[f155mph]

The only way you can increase the flow is to increase the amount of water. So, I would have the res with two outputs, one for each pump. Then get a block with dual inputs and one output and have it go to the rad and then back to the res. In theory you are running twice the amount of water to the pump. Run the two pumps inline so you don't add heat. Hope you understand what I am saying.