Large non-return valve

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scottward

Guru Class Expert
Oct 26, 2007
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Brisbane, Australia
Is it possible to put a one way valve on some 1/2" or 3/4" tubing such that water can only flow in one direction?

If this is possible, what I'm thinking is that I might be able to put a check valve between the outlet of my circulation pump and the intake of my AM1000, such that in the event of a power failure any potential gas build up can't find it's way back up the line into the impellor chamber hence creating the potential to dry run the pump.

It would most likely be water in the line I suppose, but in the (bizzare) event that a large amount of CO2 was immediately after the check valve, does the check valve also suppress backward flow of gas, or is there something specific about the design such that it would only work for water?

Sorry for the dumb question. It is because I am dumb.

Scott.
 
B

Biollante

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Well, Yes!

Hi Scott,

The basic answer all the way around is “yes.”:gw

I’ll let the smart folk explain the hows and whats best.:eek:

I would want more than a single check valve for primary protection.;)

Biollante
 
G

Gerryd

Plant Guru Team
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Sep 23, 2007
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Scotward,

A 'one way' valve and a check valve are the same thing....

they come in many sizes.. the better ones will have a replaceable 'flapper' in case they wear down over time..

These are must haves when using a sump even with a 'siphon' break air hole....

The LFS should have plenty in stock....
 
S

scottward

Guru Class Expert
Oct 26, 2007
958
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Brisbane, Australia
Cool, thanks guys I will check them out.

Do you know if they will work with reverse gas flow as well as liquid?

e.g. if my AM1000 has a whole heap of gas build up at the top, and the power gets shut off, I want to be able to stop this gas bubble going up into the impellor chamber. This has happened to me before (lucky I noticed into before my pump was damaged by dry running).

There would most likely be water above the gas but before the check valve anyway, but, just out of interest, I would assume that gas pressure coming back up through the check valve would also actuate the, I assume, flapper type, valve inside it?

There is an irrigation shop selling selling Anka check valves near me:
http://www.ankaproducts.com/wa.asp?idWebPage=36992&idDetails=169

Gurus - would these be ok too? I can just walk in and buy one of these. Would they work just as well as the ones Tom posted.

Scott.


Scott.
 
H

Htomassini

Guest
The other thing to keep in mind is that if you have a solenoid for the co2 plugged to the same circuit as the co2 pump then when power goes out the flow of gas should stop as well.


Henry t
Sent from my iPhone using Tapatalk
 
S

scottward

Guru Class Expert
Oct 26, 2007
958
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18
Brisbane, Australia
I have a solenoid, so all good there.

I think the Anka product that I mentioned above should do the trick, it's made in New Zealand.

Could somebody please take a look at the link above and comment?

Scott.
 
S

scottward

Guru Class Expert
Oct 26, 2007
958
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18
Brisbane, Australia
I'm seeing plenty of brass 20mm 3/4" check valves - can I use these? Or will the brass be no good with lower pH?

I'm thinking about copper leaching into the water.....??

I have found those True-Union swing valves at Marine Depot, but they want $114 to post one to Australia. Hmmm. Perhaps I'll try Aqua Cave....

Any other stores in the US that will post one out to me?

Can't seem to find them in Australia. Plenty of irrigation shops etc, but I'm not sure how well there product will work....

Edit: I just got a reply from an irrigation shop saying that the check valve won't work with aquarium pumps as they don't have enough pressure and if they were to push the valve open I could expect 75% loss!! Oh no!

Tom and gurus, if I were to buy one of the True-Union valves (or the other ones linked above), will this have an impact on the flow rate through my system? I don't want to loose a lot of flow!!!

Scott.
 
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S

shoggoth43

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Bear in mind that the check valve will fail at some point unless you maintain it. Use at least two in series. Some have flappers/plungers that are just compressible enough as to be worthless and cause "bouncing". In other words, the water column compresses the disk enough that it springs back and some additional water gets through and then slams shut again and bounces. This has a characteristic Thunka-Thunka sound to it. Eventually all your water ends up on the floor. It's still better than nothing when this happens since it gives you time to discover the problem, but of course this will happen over a long weekend or something when you aren't around to catch it. Newer valves might be better designed at this point. I had a few do this and I won't use them anymore if I can avoid it. Plan for failure and you won't be disappointed. :)

-
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S

scottward

Guru Class Expert
Oct 26, 2007
958
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Brisbane, Australia
I still haven't had any luck finding a PVC swing check valve. I have located an AquaSonic brand for $40, but it seems to be taking for every to track down one...

Is a brass swing check valve really that bad?

Take a look at this:
http://www.hoseonline.com.au/Fittin...-Check-Valves/Brass-Swing-Check-Valve-12.html

Only $10 (or $14 for the 3/4" one which is actually what I would probably buy).

Seriously how much copper will leach into the water? I'm already dosing a little bit of copper through my trace mix and I'm doing 50% weekly water changes.

Given that these are cheap and readily available, can I just forget about the copper issue and use one?

BTW - sorry if this is a dumb question - is it ok to screw plastic hose tails into a brass fitting like this?

Scott.
 
S

scottward

Guru Class Expert
Oct 26, 2007
958
10
18
Brisbane, Australia
Jim Miller;71025 said:
http://www.amazon.com/dp/B001EU5YH4/?tag=barrreport-21

this one is 3/4". i just bought a 1" one. how big do you need?

jim
Click to expand...

Hi Jim,

I appreciate the help, but:

Important Message
Swing Check Valve - 3/4 inch FPT x 3/4 inch FPT cannot be shipped to the selected address.

They obviously don't like Aussies! :(

From previous experience, it costs $$$ for some reason to send a small plastic part here.
 
B

Biollante

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Oppressive Regimes

Hi Scott,

Australia has wicked peak tariffs on among other things, small plastic parts. Actually Thailand does the same thing.

The local manufacturers are so protected they see no need to produce a lot of items first world countries take for granted.

Biollante
 
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