True HP Aero For 2011

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indrhrvest

New Member
Trichy Bastard said:
Are you serious? For under $100 you can get one more suited to the task at hand that is a 10 gallon tank or more as it will only hold less than 1/3 of that in nutes with all the compressed air providing the pressures you'll need to supply all your proposed nozzles with instant pressure...
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The Shurflo accumulator is designed for one purpose only, to extend pump life and prevent water hammer when used with an on demand pump. The pumps are more than adequate to supply the needed volume and pressures. Accumulators do not serve the same function as receivers in a compressed air system because you can not compress water. There primary purpose is to keep pressure on the pump diaphragm to keep it from pulsing which can wear out the seals. The tank bladder is designed to act as a buffer to reduce water hammer, not "push" stored water out. Keep in mind guys.. I did plumbing/mechanical design build for a living..

Those big accumulators I see you guys use are for thermal expansion in a hot water system. A shurflo accumulator serves a different purpose than a thermal expansion tank.. which is what I see most you guys using. Just because most these tanks are considered "accumulators" they all are engineered for specific tasks.


Thermal expansion in a closed hot water system. (not needed for recirculating)



Extend pump life with an on demand pump..



Water storage for under counter R/O systems for drinking water (low volume and pressure)

 
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Atomizer

Well-Known Member
I guess we`ve been doing it all wrong :)
ELBI accumulator vessel is a device that when fitted into a pressurised water system will provide system water at a pre-set, sustained pressure
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http://www.allpumpsdirect.co.uk/nocchi-elbi-accumulator-pressure-vessels

The small tank will prevent your pump from short cycling (chattering) but it has a downside. The tank pressure will increase to the pump pressure during every misting cycle and the tank will discharge through the nozzles when the pump stops. How much depends on the tank size and pressure but it could add upto a lot of nutes over 24 hours. Water hammer shouldnt be an issue with the relatively low flowrate, you havent mentioned incorporating solenoids which are the main cause of water hammer in hp aero.
 
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indrhrvest

New Member
Atomizer said:
The small tank will prevent your pump from short cycling (chattering) but it has a downside. The tank pressure will increase to the pump pressure during every misting cycle and the tank will discharge through the nozzles when the pump stops. How much depends on the tank size and pressure but it could add upto a lot of nutes over 24 hours.
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How is it going to discharge out of the tank with a solenoid valve down stream? Once the valve shuts, whatever pressure is in the line downstream will dissipate irregardless of what size, or style accumulator you have before the solenoid. IF you were concerned with line pressure after the solenoid closes, you could wire in a normally open solenoid as a dump to fire in tandem with the normally closed ones. That would instantly drop pressure in the manifold.. but that seems a bit overkill..

I'm not saying you guys are doing it wrong, you do need an accumulator when using on-demand pumps, but I think some of you have the reasons why it is needed confused. A shurflo, or pretty much any on-demand diaphragm pump will provide more than enough volume and pressure even in an instant on configuration. The accumulator simply prevents cycling and increases pump life..

Bottom line, if you are using an accumulator to provide stored energy, something else is not engineered properly in the system. Accumulators are not meant for that purpose, they are meant for pressure variance and maintaining smooth operation of pumps. Yes, stored energy is what allows smooth operation, but it's not the purpose of the tank to provide you with volume. The pump provides the volume. The accumulator simply makes sure it's smooth volume. So having a huge tank is pointless in such a tiny system that may have less than a few gallons total in the entire piping system.

In fact, for these systems we are working with, this little guy would probably do the job..



A couple of Shurflo videos..

http://www.youtube.com/watch?v=aO7LcUnV-3U&feature=plcp

http://www.youtube.com/watch?v=x-VkmlwThD0&feature=plcp
 
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Atomizer

Well-Known Member
If i had a well (which i dont) i wouldnt want the pump running every time i opened the tap (faucet) to fill the kettle, i`d install an accumulator. Using a demand pump to supply the flow and pressure for the nozzles is all well and good but a demand pump wont run for 1 second which puts a limitation on how short the misting pulse can be. The pump will wear out faster if you cycle it upto 1000 times a day.
Bottom line, if you are using an accumulator to provide stored energy, something else is not engineered properly in the system.
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In a low or medium pressure system that could be the case. If we omit the accumulator, the system fails to meet the design criteria, namely short pulse capability and minimal pump runtime which in turn contrbutes to reducing water/power consumption and gives better long term system reliability. I think these were your original design goals too, draining the manifold using a normally open solenoid after each misting would waste more nutes :)
 
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indrhrvest

New Member
Mike Young said:
You're going to have a tough road ahead if you keep going about in this manner. But hey, I'll watch.
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That's what R&D is for.. I have to start somewhere and in the end, I can't rely on other peoples work. What works for you, might not work in this design. I have to consider that the system also needs to support the growth of micro greens using grow mats. In order to be modular, there has to be some compromise in the design.

fwiw.. I do not expect my system to use short spray times. It's going to be in the 10-20 second range. I'm fully aware that this will not result in true Aeroponics, but that is not my goal here.
 
Trichy Bastard

Trichy Bastard

Well-Known Member
indrhrvest said:
That's what R&D is for.. I have to start somewhere and in the end, I can't rely on other peoples work. What works for you, might not work in this design. I have to consider that the system also needs to support the growth of micro greens using grow mats. In order to be modular, there has to be some compromise in the design.

fwiw.. I do not expect my system to use short spray times. It's going to be in the 10-20 second range. I'm fully aware that this will not result in true Aeroponics, but that is not my goal here.
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That's fair- I think we just jumped to the conclusion that you were still trying to make an attempt at the style of growing we strive for here. If you're having fun and enjoying the process, I can't put you down for that. We all have our own reasons for the paths we take- so I'll sit back and enjoy watching you follow your bliss. Of course when you post you'll have to expect to get feedback, but everyone has a genuine interest to help eachother here is all.
 
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indrhrvest

New Member
Trichy Bastard said:
That's fair- I think we just jumped to the conclusion that you were still trying to make an attempt at the style of growing we strive for here. If you're having fun and enjoying the process, I can't put you down for that. We all have our own reasons for the paths we take- so I'll sit back and enjoy watching you follow your bliss. Of course when you post you'll have to expect to get feedback, but everyone has a genuine interest to help eachother here is all.
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There is a lot of things I'm doing with the design that I haven't even mentioned. Have you ever run two pumps in parallel and made one a primary and one a lag pump? There's is so much more to plumbing than just throwing a pump in. The Shurflo's are great pumps because you can adjust the pressure switch setting and run the pumps staggered. You can adjust the pressures in the accumulators as well. I'm not going to give away all my knowledge, I have to have something to sell lol..

With staggered pumps, one pump works harder than the other. It's also a sort of fail safe because if one pump fails, the system will know it. You can setup pressure switches to trigger alarms etc.. Hell, you can even incorporate fuzzy logic!

Just have some faith guys.. mechanical design build was my career for 10 years.

Once I get the system built, I'll probably need some help "tuning" it, but as far as the delvery system.. I think I can handle it :) (I hope so)
 
Trichy Bastard

Trichy Bastard

Well-Known Member
Yes- the logic is fuzzy... :D
...Let's hope it can xfer to the roots!

And for the record, with what we need the accumulator to do (compress air to use as energy storage for the water pressure), an expansion tank is able to carry out the job just fine in my application- it's just able to tolerate higher temps as well, but no need for that in this of course. I just found expansion tanks were also able to tolerate higher pressures than most of the accumulators out there and at a decent price. I wouldn't discount the reliability an accumulator can afford in a power outage either... So perhaps no one is wrong here, we are just showing our reasons for our ways of doing things. My logic is sound to me, as I am sure yours is to you.
 
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indrhrvest

New Member
Trichy Bastard said:
I wouldn't discount the reliability an accumulator can afford in a power outage either... So perhaps no one is wrong here, we are just showing our reasons for our ways of doing things. My logic is sound to me, as I am sure yours is to you.
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Power outages are remedied by having a dedicated circuit for your pump and solenoids that are tied into a backup generator :).

Think commercial here.. large 100+ unit operations.. $500K-$1M builds. Crowd funding laws are going into effect in 2013, this idea is a no brainier and fits in well with the current financial and social climate. There is a far greater picture here I'm painting.
 
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Atomizer

Well-Known Member
Burlap runs £36 ($56) for a 46m x 1.37m roll, reused 3x that would provide 2035 sq ft of growing area. (same area as 63 8x4 chambers)
 
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indrhrvest

New Member
Atomizer said:
Burlap runs £36 ($56) for a 46m x 1.37m roll, reused 3x that would provide 2035 sq ft of growing area. (same area as 63 8x4 chambers)
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Interesting.. I have a design that uses 4 wires per inch stainless mesh and .75 stainless square tube frame that will basically bolt to the bottom of an open top lid for our system. You could then lay in a Coco matt, Sure to Grow matt, burlap, filter media.. or whatever suits your fancy. I'm looking forward most to testing that out.. 64 s/f of micro greens is exciting.

Edit: it appears polyester batting is the way to go..

Our system would be quite a bit cheaper than this monstrosity. http://www.aerofarms.com



 
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indrhrvest

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