Actuated valve - Mark II

[karimwassef]

I designed the first DIY actuated valve in 2013 and it has been in service for a couple of years. Older threads cover that design and how to maintain it, etc...

It's biggest drawbacks were size and the imperfect seal that allowed water to trickle through slowly (through the valve, not leaking to the outside = dripping, etc...)

So, with a little experimentation, I'm going to a cheaper, smaller and more robust version. It will be controllable by my Apex or an Arduino.

It's a simple knife gate valve and linear actuator:

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[Bent]

Great option for surge tank.

 

[karimwassef]

Yup. That's what I'm using my current version for and this will replace that and allow me to experiment with actuated siphons to the sump. Passive siphon to the sump doesn't work well with massive surges.

 

[RocketEngineer]

You would do better to place the actuator in front or behind the valve to make the arm connecting the actuator to the valve handle as short and aligned as possible. The way you have it now, that round plastic piece is being bent every time the actuator moves. Eventually it will break.

 

[karimwassef]

Thanks Rocket. Good point. I think a metal rod will do better, but plastic was available for prototyping.

Putting it inline doubles the size of the mechanism. This parallel configuration is the most compact I can see making it. My current design is inline and two feet long, so this will give me a lot of space back.

So I'll bring the parts together and go with a steel rod. Would that make it more robust and keep it small?

I'm also looking at a double configuration with one actuator and two gate valves. One on either side. They can be reciprocating (0-1, 1-0) or in parallel (0-0, 1-1). I hadn't thought if if but that should balance the moments around the actuator shaft?

 

[RocketEngineer]

What would happen if you mounted the actuator to the wide flat part of the valve instead of to the board? Sure the end of the actuator would be beyond the valve handle but they can then be connected with a short linkage. The bending load on that linkage would be much smaller than on the long bar you have now. The linkage could either be straight or a slight L shape depending on how things align.

 

[Sonicboom]

Tagging, i agree with rocket, place actuator on top of valve but remove the white curved handle and weld or solder a 90 degree piece to the shaft would make it that much more precise.

 

[karimwassef]

Hmmm. Good feedback. Love it because it could make the assembly even smaller.

The flat part of the PVC and the bottom of the actuator don't sit flat. I can make an intermediate shim to line them up, it's just harder.

The elbow is tricky too. I can't weld. I'm thinking of an old worn out Allen Key but I need 8 of these valves made. I also can't turn the actuator since the curved sides won't sit flat on the flat wide part of the valve. What I really need is an LT shaped piece that's just the right dimension.

The T connects to the valve's T and then the short part of the L connects to the actuator. The two connect to each other.

Maybe I can use threaded rod and slotted steel strips? Hmmmm

 

[karimwassef]

I wish we could share sketchup models here so we can try things out on the same model. I can post it to the 3D warehouse, and anyone can download it then. You guys use sketchup?

 

[Sonicboom]

Yes!, something the shape of an allen key, I see a light bulb over your head! maybe a side shot of the setup would help?

 

[Sonicboom]

If not then something like this where it is off to the side. 3rd picture

http://www.alibaba.com/product-detail/90-degree-aluminum-bend-pipe-for_580722190.html

 

[Bent]

Love the ingenuity, but how is this any different than a solenoid?

 

[karimwassef]

Two Allens with a 90degree shaft connector?

Where do I find 16 worn out 1/4" Allen keys?

I think the threaded rod could work. If I can bend it though, it may wear out over time.

I could take a torch to it...

 

[karimwassef]

Love the ingenuity, but how is this any different than a solenoid?

No solenoids for 2" and 3" , or 4" PVC... There are pool valves that work off 24V but those things are insanely expensive. $300 at 2", $600 at 3", $1200 at 4" and that's the trashy companies' prices. High end models are double.

The actuator I have is a 250lb force actuator that runs off 12V and has limit switches built in for $40. The valve is $20 at 2"... Add $5 to assemble = $65 DIY.

Also, the linear actuators are so easy to control with an Arduino or Apex with a relay board. I'll cover that and the coding later.

 

[Sonicboom]

Getting ideas yet?

 

[karimwassef]

Plenty of ideas all the time... Double L is good but I need the Ls in a 90degree configuration.

The two Ls have a flaw, the one attached to the actuator T has a moment around and can loosen and turn over time if the connection to the other L isn't a hard & solid 90.

In the original configuration, the T was straight to the bar.

 

[Sonicboom]

Oh sorry, i was merely posting the image as a quick solution to finding an already bent rod, and this would give you two for 1..lol

 

[karimwassef]

It's good. Maybe something already exists that's the right shape

 

[Bent]

No solenoids for 2" and 3" , or 4" PVC... There are pool valves that work off 24V but those things are insanely expensive. $300 at 2", $600 at 3", $1200 at 4" and that's the trashy companies' prices. High end models are double.

The actuator I have is a 250lb force actuator that runs off 12V and has limit switches built in for $40. The valve is $20 at 2"... Add $5 to assemble = $65 DIY.

Also, the linear actuators are so easy to control with an Arduino or Apex with a relay board. I'll cover that and the coding later.

Ah ok.

Can you control the amount it's open? That would be cool.

 

[karimwassef]

There are actuators with impedance control and others with quadrature encoder control.

They're usually small power, high control and more expensive.

I got some for accurate reagent dispensing (another project).

I was looking at greater control for things like protein skimmer optimization, slow flow variation, tank to sump actuated siphon control, etc...

My surge has only one major flaw right now. I worked out all the details from the surge reservoir to the DT, and completely forgot about the overflow to the sump.

The surge creates ZERO bubbles! But the flow to the sump creates massive bubbles that are circulated by my main pump... So sad to get so close and then miss a piece like that. That what this tiny actuator will allow me to do- actuated overflow control to keep the siphon air intake to zero during a surge and under normal flow...