Pump for 150 gal airlift?

[bonginit]

Wondering if anyone experienced with larger size brewers has any pump reccommendations for a 150 gal conebottom airlift/vortex brewer.
I've been using this linear piston pump for 15 gal in a trashcan (airlift) and I absolutely love it. 100% worth the high price compared to a cheap diaphragm pump. You can never hear any pump noise at all, just splashing. I've been running it a LOT the last couple years and it has never had an issue or needed maintenance yet. I've helped a couple friends build 15gal brewers as well and they are running the same pump with similar silent, reliable performance.

http://www.jehmco.com/html/lph45.html

The largest model(120) of these pumps puts out ~5CFM @1.5psi but I don't know that it would be sufficient. According the microbemans site 150 gal should be supplied with more like 7CFM. It also states that airlifts can get by with lower air inputs though so I wonder if 5CFM would do it. I also wonder what sort of flow the pump would actually produce at the bottom of the ~4ft tall tank.
I'll call the manufacturer and ask about the realistic output in this situation.
In really large brewers, like 500+gal I'm assuming one uses more of a high pressure "compressor" than just a "pump"?

Any input much appreciated.

 

[rik78]

from Micro web jage

"the minimum flow required from an air pump to make compost tea while maintaining the DO2 at 6 PPM, is 0.05 CFM per gallon while the optimum flow is 0.08 CFM per gallon or greater. (the only exception was when utilizing airlifts)"

online conversor

http://www.onlineconversion.com/flow_rate_volume.htm

I hope it helps

 

[Microbeman]

I would use a 12+ CFM regenerative blower for 150 gallons but it will be loud. If you want quiet you could use two pumps ganged or two airlifts.

Many pump producers and pump engineers are confused about airlifts in this application. They do calculations based on the depth of the tank without considering that the volume/mass in the tank exerts sufficient pressure through the riser pipe to offset the back pressure overall and therefore skew the standard depth back pressure math. The only lift power required is related to a portion of the weight in the riser pipe and the distance over the top of the container. This is usually only inches.

I won a debate over this with two of the top mechanical engineers in North America. They could not overcome what they had been taught in school with logic.

Anyway the point is really having sufficient air to generate dissolved oxygen, not just operate the lift.

The Logical Gardener

 

[bonginit]

Thanks!
I was thinking that the lifting action would reduce the backpressure quite a bit. It does make sense it would only have to lift the few inches of head to keep the flow flowing.
I'm leaning towards just using two of the 5cfm pumps and two airlifts. The sound level is a big incentive. The blower would move more air though and it looks like even more efficient CFM/Watt.
Still I think I would wish I had just forked out a couple hundred extra for the silent pumps. Years of quiet operation sounds worth it as long as the air is enough.

Think 10CFM would do in two airlifts?
What size pipe would you recommend? 1.5"? 2"?

The tank is 150gal capacity but I'll probably set the returns a bit below the top. I think I'd see 130-40gal in actuality.

 

[bonginit]

One more thing MM,
I don't know if it's been discussed in the sticky thread, but can you share any tips on making a diffuser? or would you sell me a couple? I know you've done significant R&D on them...
Thanks a heap

 

[Microbeman]

bonginit; Can you contact me outside the forum regarding that?

 

[bonginit]

oops i guess that's right. I'll be in touch...

 

[bonginit]

no longer option to edit posts?