Timed siphon valve - automatically alternating between constant flood and flood & drain

[Averan]

Am I crazy or is this a crazy good idea?  :D

I've been thinking of the many benefits to a constant-flood setup, but I also like flood & drain with a siphon.  My crazy idea is to use solenoid valves on a timer, connected to the top of the siphon, to break the siphon whenever I want.  Instead of passing water through the valve, I'd just let air go through.

Some people, myself included, have cycled between F&D and C-F by opening the cap off the top of their siphon.  With a timed solenoid we could control this automatically!

All you need to do is open and close a small air hole to either allow the siphon to function (F&D) or to run constantly overflowing (C-F).

This setup would allow us to run C-F during the heat of the day to minimize evaporation and heat gain and then switch to F&D at night to maximize oxygen and aerobic bacterial digestion.  In the winter this could be reversed, running F&D by day to pick up heat stored (in a GH) and C-F at night to minimize heat loss.

While keeping the pump on constantly does not conserve electricity at night, it has been known to increase the life of the pump.  It's also helpful to maintain flow through the fish tank which is why I've never really been a fan of putting the pump on a timer.

Am I missing something obvious here or could this be a really great and useful idea?!?

Now I just have to rig up a test model....

[Japan Aquaponics - アクアポニックス 日本]

ok, if we are thinking outside of the box then how about this... as I understand it we just need a hole in the top of the bell siphon that can be closed or open.... closed will allow the syphon to run, open will allow air in and just turn it into a simple flood and drain system... is that right?

How about a small contraption on top of the bell, that houses a steel ball that fits over the hole and would seal it completely when it is dropped over it.  Above the steel ball would be a piece of metal that becomes magnetised when a current passes through it.  Perhaps a small solar panel above that.

So when you want it to run as constant flood, a current is triggered that magnetises the metal and so attracts the steel ball - allowing air to flow in.   When you want to siphon then the current is stopped and steel ball drops back down to cover the air hole... so siphon can run.

You just need a simple guiding method to make sure the steel ball drops in place and it should work?

How about something like that?  Would use very little current I think and no moving parts as such?  Well, just an idea to throw out there - I am sure that there would be difficulties, but it is just an out-of-box thought!

[Averan]

hah!  i love the magnet idea! yes.  this would be even smaller/compact and no motor with moving parts to wear out.  have a rubber gasket on top of the hole for the ball to sit in and it would seal pretty well.  great stuff, now i gotta sketch this up!

[Japan Aquaponics - アクアポニックス 日本]

Jolly good!  Thought it might be interesting and easy to set up.  I imagine something like a reducer on top of the air hole so that when the steel ball drops it is directed straight over the hole...something like that.  I am sure that as the amount of electricity needed would be minimal then you might be able to get away with a small battery and a tiny little solar panel type thing on top... like on a phone solar charger, or a garden light perhaps.  Would love to see it made and in action!

[Averan]

no reducer needed as long as the tube the ball is in is just large enough for the ball itself.  being round, it will settle snuggly into a properly sized hole.

yes, the ideal would be for it to be fairly autonomous and wireless.  so some tiny simple controller would be best.  otherwise you'd have to run wires to each bypass switch on a siphon from wherever your timer is located.

[Averan]

Rupert:  I neglected to mention that I'm working on hybrid systems with media, DWT and NFT all connected.

[Averan]

I found some air valves that might work without having to invent one myself:

http://www.amazon.com/ELECTRIC-SOLENOID-STATE-NO-Plastic-PERFECT-Su...

http://www.amazon.com/Normally-Closed-Brass-2-Way-Solenoid/dp/B005E...

http://www.clippard.com/store/byo_electronic/byo_mouse_valves.asp

http://stcvalve.com/solenoid_valve_specifications_dimensions_2P_ser...

[TCLynx]

Essentially that is what a solenoid is, an electromagnet that when energized will move the actuator.  Trick is to find one that can handle being energized for half a day (many of them will melt down if energized for more than 30 seconds at a time without about an equal rest period between being energized.)

[Averan]

there is plenty of info about the difference between constant flood and flood & drain, you'd be surprised at the results.

i'm talking about cycles of 12 hours on or off.  a stepper motor might be more appropriate for these intervals, but i haven't found an air valve small and cheap that uses one.  a servo set on some auto-reversing switch could work, but again, not an industry-standard solution and thus hard to find pre-existing.

i would simply drill and thread a hole right into the pvc cap, screw in whatever type of connector needed to feed into the air valve and call it a day.  =)

modulating the fill or drain portion of a balanced siphon seems like asking for headaches.  they don't tend to have a wide operational range as evidenced by the plethora of forum posts titled 'help!  I can't get my siphon to work!'  :D

[Jonathan Kadish NYC AA Chair]

Try this little guy to pick up the ball

http://www.amazon.com/Elenco-SCP-08-Snap-Circuits-Electromagnetism/...

[Averan]

I am finding stepper motor air valves in the automotive industry as idle control valves, and 12V even, but no idea how I'd adapt one to this purpose: http://compare.ebay.com/like/280804056065?var=lv&ltyp=AllFixedP...

Yes Jonathan, an electromagnet is the basic idea we've considered, but I'd rather use an existing part if there is one before tinkering something together.  Thanks for the link.  :)

[Averan]

Even closer, a 'bowl vent solenoid', another car part: http://www.ehow.com/facts_7246413_bowl-vent-solenoid-do_.html

http://www.ifsja.org/forums/vb/showthread.php?t=129255

And these are designed to hold state for much longer intervals and activated by a simple power-on/off.  I could control it with this 12V timer: http://www.ebay.com/itm/DC-12V-LCD-Digital-Power-Programmable-Timer...

Here's a new one for $30: http://www.ebay.com/itm/3-8-Electric-Solenoid-Valve-12-Volt-Air-Gas...

I'm sure I can find them used somewhere for cheaper, but that's not bad.

[Averan]

good idea joe!  it would require an overflow drain for each bed, which means more plumbing.  certainly a viable approach, especially if you already have overflows in place!

you've given me a great alternative to consider, thank you!