Bidirectional tidal flow

[Delphinus]

A few years back I looked into the possibility of creating this kind of flow but using one pump. It was before OM was around. What I thought about using was a MOV (motor operated valve - electric in this case, although you can get pneumatic-activated as well) on a 3 way mixing valve. The trick is having the right ball in the valve so that as one side begins to close, the other begins to open so that the total flow through the valve remains constant at all times.

The reason I didn't pursue it was the cost of the MOV's was too prohibitive for me. I forget exactly where they were landing in price point specifically but I do recall thinking I would have done it if I could have found one for $200ish so I think it was well above that. The pneumatic ones were cheaper but then who wants to have a compressor going all the time and "psshhhhh!! psssssh!!! psssshhhhh!!" going on all the time in the tank room.

[sphelps]

Yeah and to use one pump you'll need at least 4 of those valves. A second pump with some additional holes and plumbing will be easier, cheaper and more reliable.

[MitchM]

LOL.

It sounds like it might boil down to another reeflo pump.
Now I need to find out how they stand up to constantly turning on and off.

I did find a 2" solenoid w/valve on the 'net, for a measly $2200.00.

Mitch

[The Codfather]

Don't know about prices, but here is a little info. from sequence:

http://www.mdminc.com/Doc/Sequence%2...ata_Sheets.pdf

[golf nut]

You can buy an $8 reed switch, sense the position of the drum then hook that to an Areotronics timer, select the time delay and you are done like dinner. net cost $39 .

[MitchM]

Codfather, thanks!

golf nut,

So I would use a 2-way OM unit?
What is a reed switch and Areotronics timer?

Thanks,
Mitch

[sphelps]

A reed switch works on magnetism, same type of switch you'd find on windows and doors for alarms. Problem is the OM has a thick plastic casing and you'd need pretty powerful switch to work properly and you would have to enclose one end within the drum which offers will space. Plus you'd need two switches for the two positions meaning you'll also need a smart relay to understand the two switches and control the system accordingly. It's certainly not as simple as described and the cost would be beyond $39.

[sphelps]

Not to mention the OM drum is driven by powerful magnets, I can't see a reed switch working properly to begin with.

[lastlight]

If you just tee off your closed loop pump and have a valve on either side of the tee why do you need 4? Are you concerned about valving off inlets on either side too? If the inlets were more or less centered why not use just 2 valves?

I think a guy on RC bought a morized butterfly valve or something like that by Hayward. They're pricey but from what I read the pricey ones are extremely reliable.

Overall likely cheaper to use a pair of DC controlled pump for each side. Red Dragon is apparently releasing new pumps as the previous generation had issues. I've heard good things about similar pump but can't quite recall the maker or the name sorry.

[golf nut]

How did I edit your post?