Brown Pump - Double Up

[_HOME_BREW_WALLACE_]

I have read a heap of comments about the poor performance of brown pumps in recirculating system breweries, and wondered if 2 brown pumps were used simultaneously, would this help the pressure/flow issues required by some recirc. breweries?

A shit artist's impression :

Brief description: - 1/2" into and out of the pumps, through 5/8" in & out manifold (if u know what i mean).

 

[seravitae]

Pumps running in parallel should provide same head pressure as one pump but twice the flow assuming no other bottlenecks.

Pumps running in series, i am not sure. Probabably same flow rate but higher head pressure, or just limited to the head pressure of the best pump, maybe.

I have read a heap of comments about the poor performance of brown pumps in recirculating system breweries, and wondered if 2 brown pumps were used simultaneously, would this help the pressure/flow issues required by some recirc. breweries?

A shit artist's impression :

Brief description: - 1/2" into and out of the pumps, through 5/8" in & out manifold (if u know what i mean).

 

[_HOME_BREW_WALLACE_]

Pumps running in parallel should provide same head pressure as one pump but twice the flow assuming no other bottlenecks.

Pumps running in series, i am not sure. Probabably same flow rate but higher head pressure, or just limited to the head pressure of the best pump, maybe.

I thought with the larger inlet/outlet on the "Y" fitting it should allow for the faster flow.

 

[seravitae]

Well, not strictly true. It gets complicated and I am not a physicist... But, you can have two pumps on a tee where all inlets and outlets are the same, in which case you *might* have a bottleneck and reduced flow (greater than 1 pump less than 2 pump), or, you may get up to double the flow, with a doubling of fluid velocity. It depends on the pump parameters I believe, ie suction and/or head pressure depending on whether the tee is in front or behind the pumps.

To ensure you don't have bottleneck issues, if you have two pumps with 1/2" inlet/outlets, then the tee you want would have two pump inlets at 1/2" and your 'main suction inlet' to have a cross sectional area equal to 2 times 1/2", whatever that is.

Anyone please feel free to correct me if I am wrong and I will change my crappy maths:

d = 1/2" = 12.7mm
r=d/2
r=6.35mm
a=pi*r^2 = 3.14159*(6.35)^2
a=126.67mm^2

to prevent any bottlenecks, width of main suction inlet is a*2

a*2=253.35mm^2.

What diameter tubing is this?

a = pi*(r^2) let a=253.35mm^2

253.35/2 = 3.14159*(r^2)
253.35/3.14159 = (r^2)
r^2 = 80.64
sqrt(r^2)=r
sqrt(80.64)=8.979mm
diameter = r*2
8.979*2 = 17.958mm
17.958mm is 0.707 inches


5/8" is 15.875mm, which is pretty close, and probably 'not a problem' for this setup.
for true prevention of a bottleneck though you'd need one a bit bigger.

3/4" is 0.75 inches, which is slightly greater than 0.707 inches, and is easier to obtain than 5/8" i think....... so 3/4" is the ideal choice for master suction/outlet lines for no bottleneck given 'doubling up' two 1/2" pump lines.

 

[_HOME_BREW_WALLACE_]

Well, not strictly true. It gets complicated and I am not a physicist... But, you can have two pumps on a tee where all inlets and outlets are the same, in which case you *might* have a bottleneck and reduced flow (greater than 1 pump less than 2 pump), or, you may get up to double the flow, with a doubling of fluid velocity. It depends on the pump parameters I believe, ie suction and/or head pressure depending on whether the tee is in front or behind the pumps.

To ensure you don't have bottleneck issues, if you have two pumps with 1/2" inlet/outlets, then the tee you want would have two pump inlets at 1/2" and your 'main suction inlet' to have a cross sectional area equal to 2 times 1/2", whatever that is.

Anyone please feel free to correct me if I am wrong and I will change my crappy maths:

d = 1/2" = 12.7mm
r=d/2
r=6.35mm
a=pi*r^2 = 3.14159*(6.35)^2
a=126.67mm^2

to prevent any bottlenecks, width of main suction inlet is a*2

a*2=253.35mm^2.

What diameter tubing is this?

a = pi*(r^2) let a=253.35mm^2

253.35/2 = 3.14159*(r^2)
253.35/3.14159 = (r^2)
r^2 = 80.64
sqrt(r^2)=r
sqrt(80.64)=8.979mm
diameter = r*2
8.979*2 = 17.958mm
17.958mm is 0.707 inches


5/8" is 15.875mm, which is pretty close, and probably 'not a problem' for this setup.
for true prevention of a bottleneck though you'd need one a bit bigger.

3/4" is 0.75 inches, which is slightly greater than 0.707 inches, and is easier to obtain than 5/8" i think....... so 3/4" is the ideal choice for master suction/outlet lines for no bottleneck given 'doubling up' two 1/2" pump lines.

You're a wealth of knowledge sera! what you just put down somewhat makes some sense. and what is better, i actually have some 3/4" in the shed . I was only thinking the 5/8" because if you have had a look at the brown pump in/outlet it is oval and not round. But never-the-less it will happen with the 3/4" and i will post results.

Cheers! :icon_chickcheers:

 

[Sammus]

two pumps in series increases head pressure. it's a tried and true method of increasing pressure in highly restrictive water cooling loops for pc's that enthusiasts have been using for years. I guess it probably depends quite a bit on how the pump is designed too, though, so still take it with a grain of salt

 

[QldKev]

By the time you have 2 x pumps, plus 2 x Y, plus oversize valve, plus power supply and extra fittings to fit it all up, it doesn't seem like a cheap pump. Why not just chuck a few more $ in a do it the way brewers have done for many years with a reliable March pump, and not have the dramas of overheating / grain getting stuck etc?

edit: I don't mean to sound rude in this post, it just seem to be a lot of extra stuff for what started life as a budget pump option.

 

[seravitae]

You're a wealth of knowledge sera! what you just put down somewhat makes some sense. and what is better, i actually have some 3/4" in the shed . I was only thinking the 5/8" because if you have had a look at the brown pump in/outlet it is oval and not round. But never-the-less it will happen with the 3/4" and i will post results.

Cheers! :icon_chickcheers:

No problems mate, hope it helps you come up with a solution that fits your needs.

two pumps in series increases head pressure. it's a tried and true method of increasing pressure in highly restrictive water cooling loops for pc's that enthusiasts have been using for years. I guess it probably depends quite a bit on how the pump is designed too, though, so still take it with a grain of salt

http://www.engineeringtoolbox.com/pumps-pa...rial-d_636.html <--- yep, that tends to agree too. It actually, to my logic, seems counterintuitive to suggest that centripetal style pumps in series would increase overall head pressure, but it seems to be the case. I already do multi-stage pumping with vacuum for lower pressure, but wasn't sure if it worked for generating higher pressures. Learn something new every day.

By the time you have 2 x pumps, plus 2 x Y, plus oversize valve, plus power supply and extra fittings to fit it all up, it doesn't seem like a cheap pump. Why not just chuck a few more $ in a do it the way brewers have done for many years with a reliable March pump, and not have the dramas of overheating / grain getting stuck etc?

edit: I don't mean to sound rude in this post, it just seem to be a lot of extra stuff for what started life as a budget pump option.

This is also something to consider. If you had a few brown pumps lying around or easy access to one, it might be relatively cheap to strap two at once. Would it be worth it? Depends on the situation. I would say if you have two brown pumps it might be cost effective for some, but to go beyond two brown pumps it's time to go for a march

Cheers

S