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High cycle Rainbird and passive valve testing

 

I have a test valve setup running with two Rainbird CP075 valves and two 3D printed passive valves, the PEEP I designed and a PANDA PEEP I printed here in PETG. A BenchDuino prototype board with an Arduino Mega 2560, display and lots of switches controls a Keyes 2-channel 5 V relay board that controls the Rainbird valves. A BME280 pressure sensor is used for monitoring. An old heavy duty 13.8 v linear power supply powers the BenchDuino and valves. Air is supplied by a compressor next to the setup with a 3' hose.

There are flow restricters between the Rainbird valves and the PEEP valves and on the outlet of the PEEP valves.

A simple program cycles the valves and monitors the P sensor. I will add to the program later but I wanted to get the valves cycling. Now I'm running with a 1 second fill and 1 second exhaust.

The pressure sensor is mounted in a cap in a T with the wires brought out through the cap. The first two attempts at sealing the wires with silicon and latex caulk both failed at around lower than spec pressure.? My third attempt is using JB weld and I'll install it later today.

Initial testing was run with the initial inlet pressure spec of 50 psi. The compressor could not keep up with this and the P sensor seal blew out. Subsequently the spec was reduced to 20 psi and even that has been hard for the compressor to keep.

I have about 16,000 cycles as of this minute.

First observations:

The Rainbird valves sound like airhorns when they open at great than about 10 psi. You couldn't possible sleep with them in a room.

Sealing the P sensor wires is much tougher than I thought. I t have high hopes for the JB weld approach.

It will take some time to size and balance the two the flow restricters to reduce the load on the compressor yet provide enough flow and back pressure to open the PEEP valves.

At low pressures the compressor pressure regulator valve is highly dependent on the tank pressure. Unfortunately, as tank pressure drops the regulator open so the viscous cycle drains the tank.

Bob?? KD8CGH
 

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The BME sensors should be on the human side of the lawn sprinklers. It really shouldn’t see a pressure above 100 cm above atmospheric. ?That should be easy to seal with. ? ?Are you possibly putting them on the high-pressure side? That will destroy them.


On Apr 3, 2020, at 07:33, KD8CGH <rkayakr@...> wrote:

?I have a test valve setup running with two Rainbird CP075 valves and two 3D printed passive valves, the PEEP I designed and a PANDA PEEP I printed here in PETG. A BenchDuino prototype board with an Arduino Mega 2560, display and lots of switches controls a Keyes 2-channel 5 V relay board that controls the Rainbird valves. A BME280 pressure sensor is used for monitoring. An old heavy duty 13.8 v linear power supply powers the BenchDuino and valves. Air is supplied by a compressor next to the setup with a 3' hose.

There are flow restricters between the Rainbird valves and the PEEP valves and on the outlet of the PEEP valves.

A simple program cycles the valves and monitors the P sensor. I will add to the program later but I wanted to get the valves cycling. Now I'm running with a 1 second fill and 1 second exhaust.

The pressure sensor is mounted in a cap in a T with the wires brought out through the cap. The first two attempts at sealing the wires with silicon and latex caulk both failed at around lower than spec pressure.? My third attempt is using JB weld and I'll install it later today.

Initial testing was run with the initial inlet pressure spec of 50 psi. The compressor could not keep up with this and the P sensor seal blew out. Subsequently the spec was reduced to 20 psi and even that has been hard for the compressor to keep.

I have about 16,000 cycles as of this minute.

First observations:

The Rainbird valves sound like airhorns when they open at great than about 10 psi. You couldn't possible sleep with them in a room.

Sealing the P sensor wires is much tougher than I thought. I t have high hopes for the JB weld approach.

It will take some time to size and balance the two the flow restricters to reduce the load on the compressor yet provide enough flow and back pressure to open the PEEP valves.

At low pressures the compressor pressure regulator valve is highly dependent on the tank pressure. Unfortunately, as tank pressure drops the regulator open so the viscous cycle drains the tank.

Bob?? KD8CGH
<setup.jpg>
 

Hi James
?
That looks awesome, although I expect the plastic spring to loose tension rather quickly. It’s meant more as an emergency device and for test for groups developing vents. However, the concept is rather sound and could very easily be adapted to a metal spring. It’s just that the springs are different in each country and I haven’t found a spring that’s common everywhere. But locally adjusted PANDApeeps might be a viable solution. Since I’m designing this in my freetime and it was at the beginning nothing more than a side project to our ventilator design, resources are stretch rather thin at the time. Our focus right now ist to adapt this to an inline system for one vent/multiple patients setup. Still, any data and input highly appreciated. If you have an idea for a comparable spring (ideally a conical one for self centring) I’m game. Another option would be to mass-lasercut the flat spring out of thin spring metal sheets. Importance has risen since also in the US the Ambu PEEP valves are running out.
?
So long
?
Dominik
 

Next version. I now have the P sensors working and I'm monitoring the results with an eye to developing a failure detection algorithm. I put smaller flow restrictors in between the solenoid valves and PEEP valves and and on the PEEP valve outlets. The valves have about 30,000 cycles and appear to be functioning well.

???? Bob Benedict??? KD8CGH

setup2.jpg

 

Dominik
? This is Bob Benedict, the original poster. No idea who "James" is.
? Beautiful design. As you might see on the right hand valve I'm using a steel spring that is adjustable.
?The testing I'm doing is rapid cycling. I do not monitor PEEP open pressure so I won't see a stiffness change in the printed spring.
??? Bob Benedict?? KD8CGH
 

Revised the system again. Now I monitor the difference in pressure between the end of intake and end of exhaust and only increment the count for a valve if the difference is above a threshold. This allows me to know the count when a valve fails but continue the test with the other valve.
I also shortened the cycle time from two seconds to one second and added a battery backup to the control system so I don't loose count if there is a power glitch.

At 53,000 cycles and all valves working. The Rainbird solenoids are warm to the touch, but not hot.?

??? Bob KD8CGH
 

Bob:
Dominik is at ZHAW - Zurich University of?Applied Sciences. I found him through his Panda PEEP Valve post on thingiverse(where I scan all daily submissions for anything that might look useful to our project). I have exchanged several private emails with him checking on his progress and pointing him to your tests. He is not on this group as far as I know at this point.

James
KE4MIQ
 

ahhh - saw Dominik at the bottom of the post and thought that he was the poster.
??? 73
????? Bob?? KD8CGH
[email protected]
 

Hi Bob and James
I'm the one that designed the PANDApeep. You have an awesome setup. I'm following your progress loosely since I'm a bit overworked with adapting the Gen2 valve for multiventilator inline setups. Do you mean the PEEP valve both have seen 53'000+ cycles and are still running? That would be awesome.
We have a design for a 0.3mm thick lasercut spring steel spring fitting into the Gen2 ready and it's getting cut and tested now in Gent, Belgium. Should this work out fine it might be an option for you as well.
I don't know if I'll have the time to troll your group here often, but should you need anything concerning PEEP valves, you can reach out to me via FB or text@....
We wish you the best for your development.

Regards from Switzerland.
Dominik
 

FANTASTIC!!!? ?Your work is now being considered for inclusion within the FDA pre-EUA? submission

Gordon
[email protected]
 

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That’s extremely cool and slightly frightening.
Keep up the good work and let me know when you need something.



On 6 Apr 2020, at 15:26, Gordon Gibby <docvacuumtubes@...> wrote:

FANTASTIC!!!? ?Your work is now being considered for inclusion within the FDA pre-EUA? submission

Gordon

 

be aware that at present there is NO LIABILITY COVERAGE for anything built by any volunteers.........
I have been asking for this to be dealt with for several days but we do not have any resollution on that.
So I would suggest caution.

Gordon


On Mon, Apr 6, 2020 at 8:39 AM <dtextor@...> wrote:
Hi Bob and James
I'm the one that designed the PANDApeep. You have an awesome setup. I'm following your progress loosely since I'm a bit overworked with adapting the Gen2 valve for multiventilator inline setups. Do you mean the PEEP valve both have seen 53'000+ cycles and are still running? That would be awesome.
We have a design for a 0.3mm thick lasercut spring steel spring fitting into the Gen2 ready and it's getting cut and tested now in Gent, Belgium. Should this work out fine it might be an option for you as well.
I don't know if I'll have the time to troll your group here often, but should you need anything concerning PEEP valves, you can reach out to me via FB or text@....
We wish you the best for your development.

Regards from Switzerland.
Dominik

 

Please pay careful attention to the LEGAL RISKS that apparently we have ZERO protection for at the moment.
Gordon
 

Dominik
? The valves have 200,000 cycles and appear to be functioning well. I just changed the layout and shortened the cycle time to 0.5 second so in future we should gain 150,000 cycles a day with a goal of one million.
? I'm monitoring the change in pressure at a point in between the Rainbird outlet and the PEEP exhaust as a broad indication of function, so I don't have a precise measure of PEEP open pressure.
????? Bob Benedict?? KD8CGH
?
Dominik Textor
 

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Bob
Thanks for the update, that sounds good! PEEP terminal pressure would be interesting to see how fast the springs deteriorate.
Regards
Dominik

On 7 Apr 2020, at 00:33, KD8CGH <rkayakr@...> wrote:

?Dominik
? The valves have 200,000 cycles and appear to be functioning well. I just changed the layout and shortened the cycle time to 0.5 second so in future we should gain 150,000 cycles a day with a goal of one million.
? I'm monitoring the change in pressure at a point in between the Rainbird outlet and the PEEP exhaust as a broad indication of function, so I don't have a precise measure of PEEP open pressure.
????? Bob Benedict?? KD8CGH
?

 

Now at 675,000 cycles with all valves appearing to function.
Test system doc attached.
????? Bob Benedict?? KD8CGH

RapidTest.docx
RapidTest.docx

 

That's amazing!!
I'll report on it tomorrow morning.
Thanks!
 

Hit 1,000,000 cycles this evening. The two Rainbirds are still opening and closing every 0.5 second.
I replaced the PANDApeep and my designed PEEP with two copies of the UF designed PEEP that I 3D printed here from their geometry files. They have 75,000 cycles on them.
????????? Bob Benedict?? KD8CGH.
 

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Wow!! ?Can you document your testing with a photo or so, formal right up, and send to us?


On Apr 11, 2020, at 22:17, KD8CGH <rkayakr@...> wrote:

?Hit 1,000,000 cycles this evening. The two Rainbirds are still opening and closing every 0.5 second.
I replaced the PANDApeep and my designed PEEP with two copies of the UF designed PEEP that I 3D printed here from their geometry files. They have 75,000 cycles on them.
????????? Bob Benedict?? KD8CGH.

 

Gordon
?? I can update the 4/11 doc (post 1432).
?????? Bob Benedict

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