Anybody use this Chinese External CO2 reactor?

[ForestDave]

Indeed it might... 🙂 You can also DIY one that might do better. With this, I tested it a few years back as an air venturi and worked a charm.

View attachment 163345

You can drill a very small hole in the hexagonal nut say 1mm or even smaller if you want. Then what i yet have not tested but in theory, it should do even better. Drill this hole in an incline in the flow direction. Than take a larger drill in 4.2mm and drill a 5mm deep hole at 90° on top of the 1mm declined hole. The Hex nut has enough material to it for that. Tape M5 thread in this 4.2mm hole and screw in another 4mmxM5 hose pilar. I used one like this with a O-ring and a clamp nut.

Or use one like this with a drop of Locktite or other sealant on the thread.


And this goes again on the other end with a rubber washer.



It is 10mm internal diameter, which makes it 2mm reduction in a 16/12mm hose. 🙂 And the 1mm inlet gives a finer bubble. 🙂
But as said I didn't test it with an inclined 1mm hole, I drilled it straight and it already worked well as a venturi inlet. Later I thought I should have tried to drill it inclined. with the flow direction. There was nothing to lose to do that anyway. (Well other than snapping a drill if you are not careful.)

Sounds like a neat solution Zozo. Some skilful drilling too.

 

[zozo]

Sounds like a neat solution Zozo. Some skilful drilling too.

It's a relatively soft plastic, that's a huge plus... 🙂 But you do need to correct tap, the machine tap is pointed and the hand tap is blunt with a flat end. The latter one is needed for blind holes.

 

[ForestDave]

It's a relatively soft plastic, that's a huge plus... 🙂 But you do need to correct tap, the machine tap is pointed and the hand tap is blunt with a flat end. The latter one is needed for blind holes.

Cheers. I was wondering about that bit as I’ve only used machine taps before. I’ll look up the hand tappers.

 

[Zeus.]

Could you explain the purge valve please?

Just a way of venting air (and CO2) after maintenance/fitting, just makes life easier. I just release the air by loosening the pipe fittings to my APS EF2 after maintenance.
I haven't clean my reactors in years, as when I did do them they was basically clean.

 

[zozo]

Cheers. I was wondering about that bit as I’ve only used machine taps before. I’ll look up the hand tappers.

I believe the correct term is Blind Hole Tap, no idea actually if they come in a machine tap version. In the regular hardware store in only see machine taps that are pointed for easier guiding. And then the 3 piece set hand taps that are suitable for blind holes ad need the 3 stages for proper guidance.

But in plastic-like PVC this is peanuts, only used tap number 1, and it's already ok to screw something metal in and fit snuggly.

 

[Hanuman]

@Hanuman
Could you explain the purge valve please? Is that a simple ball valve adjusting the flow to the Venturi?
Also you have two other green valves and pipes going into the reactor, is that for fertiliser?
Thanks
Dave.

Yes that's an irrigation valve and indeed it's to adjust the flow but in reality it is more to fully close it when doing maintenance. There is no real need to regulate the flow purge valve going to the venturi port. I leave it fully open.

Also you have two other green valves and pipes going into the reactor, is that for fertiliser?

Never thought of using that for fertilizer but you gave me an idea lol
Those are 2 additional purge ports at different depth levels. If you notice the tubbing goes deeper for each. This was done at the design level in case I wanted to use different purge levels when putting the reactor in service since I wouldn't be able to open the reactor again once glued. So far I have only used the same one with the blue valve.

 

[ForestDave]

Yes that's an irrigation valve and indeed it's to adjust the flow but in reality it is more to fully close it when doing maintenance. There is no real need to regulate the flow purge valve going to the venturi port. I leave it fully open.


Never thought of using that for fertilizer but you gave me an idea lol
Those are 2 additional purge ports at different depth levels. If you notice the tubbing goes deeper for each. This was done at the design level in case I wanted to use different purge levels when putting the reactor in service since I wouldn't be able to open the reactor again once glued. So far I have only used the same one with the blue valve.

Good stuff, thank you.
When the dust has settled from my new tank build and I'm feeling flush I'll find someone who wants to go halves on a clear pvc tube as they seem to only come in 1 - 1.2m lengths.
Cheers
Dave.

 

[ForestDave]

Well, I know that clear plastic is the best for setting up a reactor, but as I had a few unused lengths of 110mm soil pipe in the garage I thought I'd try a wide version of Hanumans design as I didn't have enough height under my tank to make his recommended 60cm reactor. I'm on day 2 with it and it's not working that well yet. The venturi isn't kicking in. I added a bit of tubing inside the venturi hose joiner this morning, on the feed side to increase the restriction and lower the pressure. This hasn't helped no matter how much I adjust the flow. Now I'm wishing I'd held out for the clear pipe! 🙄 I also changed the CO2 feed pipe length this morning so that it produced the bubbles low down in the reactor as I saw Tom Barr's did this. This CO2 feed pipe was also stretched to form a taper and give smaller bubbles. The internal venturi feeding pipe has also been bent to the edge of the reactor as I saw Hanuman's looked to be favoring the edge and yesterday it was right next to the water feed pipe which I was worried might be interfering with it.
Either way, it's semi-working. After 3.5hrs the D/C is at between 12 and 20ppm at about 6bps on the CO2 Art regulator. The Reactor seems heavy so there is plenty of water in there and not just a vat of CO2. I need to re-do the venturi though as it's just not pulling anything through and at that bubble rate it would have been nice to be lime green by now.
I'll stick some photos up from my phone in a minute.
Any tips welcome!!

 

[ForestDave]

 

[ForestDave]

Few more images

 

[ForestDave]

The Venturi

 

[Zeus.]

I would have the the venturi feed pipe shorter (short as possible) within the reactor - then air pocket will be less at top of reactor

plus have a value outside to vent the reactor of air on first use.

The fact you have a pH drop means its doing something
Is the tank bubble free?
Noise levels of reactor?

 

[ForestDave]

I would have the the venturi feed pipe shorter (short as possible) within the reactor - then air pocket will be less at top of reactor
View attachment 164546
plus have a value outside to vent the reactor of air on first use.

The fact you have a pH drop means its doing something
Is the tank bubble free?
Noise levels of reactor?

Thanks Zeus.
I’ll give that a go for tomorrow. I’ve been isolating the reactor feed and sending the whole flow from the FX6 through it for 5-10 seconds once or twice hoping that would flush any trapped gas. A purge pipe makes sense though. I was going to weigh it tomorrow before start up so I could gauge how much gas is in there.
Putting an ear to it when in use you can get a sense of how much flow is going through it. Not ideal but I suppose I just need to be methodical with any changes.
When the D/C got to lime green it’s stayed nice and constant all day and there have been hardly any bubbles. Some of the few bubbles have been from slight pearling. So the tank is looking nicer!! There’s a gentle trickling sound from the reactor which is fine. I just need it to get to 20ppm a bit quicker.

 

[Zeus.]

I just need it to get to 20ppm a bit quicker.

Without duel solenoids on the CO2 reg there are limits, my fastest was 20mins for 1.3pH drop with my 500litre setup with duel solenoids/injection, but an hour to three hours is about normal with single solenoid with bigger tanks taking longer. My 50l with single solenoid/injection takes about 2.5 hours

 

[ForestDave]

Without duel solenoids on the CO2 reg there are limits, my fastest was 20mins for 1.3pH drop with my 500litre setup with duel solenoids/injection, but an hour to three hours is about normal with single solenoid with bigger tanks taking longer. My 50l with single solenoid/injection takes about 2.5 hours

Cheers. That's good to know. Do you have one solenoid pump a load of CO2 in quickly and then turn off while the other keeps going and maintains the level you're after? 20mins is pretty phenomenal for a 500L tank!!

 

[Zeus.]

Do you have one solenoid pump a load of CO2 in quickly and then turn off while the other keeps going and maintains the level you're after?

Yep, the needle valve fully open then off at lights on

I do use a PLC to control them, wouldn't trust a normal timer as with such a high initial injection rate it could soon be very bad for livestock.

 

[Hanuman]

I would have the the venturi feed pipe shorter (short as possible) within the reactor - then air pocket will be less at top of reactor

No you don't want that. You want the CO2 to partially build up in the reactor. That's what makes the mixing more efficient. The bleed/venturi port is to prevent a back pressure, usually after several hours of injections. That's why Tom Barr suggests you building bleed ports at different heights so that one can adjust the preferred level after you put your reactor in operation. It's difficult to judge what level is better as all setups/water flow are different. If you cut the tubbing short as you suggest you will have CO2 being sucked in pretty quick after start of injection and potentially start creating smaller bubbles, which definitely you don't want.

plus have a value outside to vent the reactor of air on first use.

Yes definitely. This is a must if you don't want to be scratching your head why your filter is not working if you stop it and start it again and for some reason there is CO2 or excess air in the reactor, specially in the first run.

The venturi isn't kicking in.

The internal venturi feeding pipe has also been bent to the edge of the reactor as I saw Hanuman's looked to be favoring the edge and yesterday it was right next to the water feed pipe which I was worried might be interfering with it.

No I didn't favor the edge. I just didn't have straight rigid PVC tubbing LOL. But it doesn't matter if it's at the edge or not. The important is the level. Once Co2 reaches that level then the venturi quicks in.

I am also noticing a small flaw in your reactor that makes your reactor less efficient. The top part is recessed a good ~1cm or maybe less compared to where the water arrives. This has the consequence of having CO2 accumulate in the top part of the reactor sitting doing nothing before water is actually hitting CO2. You want to have that black part at least flush with the grey part. Another more efficient way would be to build a small cone like structure inside the reactor that forces the CO2 directly below the water stream arriving from the top. That way you immediately and forcibly push CO2 to mix with the incoming water. You will see dramatic improvement.

I need to re-do the venturi though as it's just not pulling anything through and at that bubble rate it would have been nice to be lime green by now.

You need to make sure the small part inside the bigger hose connecter is cut to ~60 degree angle and that the face of the angle is facing away from the current. Make the hole as small as possible in the small tubbing connecter. In fact I melted that small connector to seal the hole and then used a needle which I heat it up and reformed a smaller hole. I had to do that part 3 times before I was satisfied with it.

After 3.5hrs the D/C is at between 12 and 20ppm at about 6bps on the CO2 Art regulator.

Not sur what your tank size is but I have 180L raw tank. Net volume maybe ~100L or so. I am pumping a constant stream of CO2. I can't count the bubbles so 6bbs for 12/20ppm CO2 actually doesn't look bad. Just make the small mods above and you should be golden just like my drop checker...😙

​

 

[Hanuman]

Noticed additional things. Your CO2 working pressure is below 20 PSI. I would increase that to 20 PSI. The more the CO2 builds up in the reactor and the more back pressure you will have. Considering you are using a CO2Art regulator which has a mediocre needle valve (no, sorry, a poorly constructed needle valve.... no, sorry again, let's be straight here, a nail), your CO2 will not be constant and I can guarantee that your CO2 will fluctuate during the day. Even without the back pressure, those Co2Art needle valves are pretty unstable. That's a known fact. I've been there.

Here is what a "needle valve" from Co2Art looks like... I will let you judge:


Here is a considerable improvement 😇:


And here is a Royal improvement, I will leave the details for another thread though. Don't want to derail things here but just to give some context on why Regs and needle valves are important:

 

[ForestDave]

Thanks, @Hanuman. I'll get to work!
The small pipe inside the venturi was beveled to at least 60 degrees and faced away from the flow but I didn't adjust the hole size. When I initially turned it on, the water went down the pipe the wrong way. I'll re-do it. 👍 Would angling the pipe 20-30 degrees in the direction of the flow also help?

I did have the regulator set at 30 PSI for the inline diffuser but reduced it two days ago as I felt that was too high and meant fine adjustments to the flow were really hard to do, I'll whack it up to 20 PSI. Sounds like the regulator might have something to do with tricky adjustments also. I'd be really interested to see your post on regulator needle valves.
Thank you for the tips!!

 

[ForestDave]

Yep, the needle valve fully open then off at lights on

I do use a PLC to control them, wouldn't trust a normal timer as with such a high initial injection rate it could soon be very bad for livestock.

Cheers Zeus.
So is it better for the plants and livestock to get to the desired CO2 PPM as quickly as possible or does it save on gas?

I'm going to have to look into the whole PLC business. I'm about to set up some fert dosers controlled by a Meross wifi power strip. They seem really solid and you don't need to re-adjust anything after a power cut, (of which we have many where I live, I think it's all the trees falling on cables). The only times I've had issues are always from human error, me pressing the wrong thing, or forgetting to save an alteration. My plan is to set the doser times twice for each dose on their own power strip and then never touch it!
PLCs sound like the future though!