PEM Cell Deuterium / Setup and Operational Basics

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Mark Rowley
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PEM Cell Deuterium / Setup and Operational Basics

Post by Mark Rowley »

After being asked a few times over the past 18 months, I finally got around to making a very basic “how to” video regarding PEM Cell Deuterium.

The video primarily discusses the operational basics of the Horizon PEM Cell, the use of a 100ml syringe for collection, and hookup to a fusor.

As shown, it’s a performing arrangement which has allowed for decent neutron production without much complexity. It’s also not to be considered the only method but rather to provide the basics for any fusioneer to improve and expand upon.

Part One
https://youtu.be/hUxv6gB3SlA

IMPORTANT EDIT: View part two first!

Part Two
https://youtu.be/Vo22d5e-H10


83BD99A2-E200-4F87-8A93-D17D420EC185.jpeg

Mark Rowley
Last edited by Mark Rowley on Sat May 01, 2021 12:53 am, edited 1 time in total.
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Richard Hull
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Re: PEM Cell Deuterium / Setup and Operational Basics

Post by Richard Hull »

Fabulous!! Many thanks from me on behalf of many current and future would be fusioneers.
I am including this in a construction FAQ.

Go to the FAQ for a full exposition on this subject

viewtopic.php?f=24&t=13995

I have asked a couple of key questions there as this post may get lost. Please answer them there

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
Rex Allers
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Re: PEM Cell Deuterium / Setup and Operational Basics

Post by Rex Allers »

Mark,
Congrats on your video. Not only on the content but also the production, very good video and audio.

----
I thought I'd post a bit of stuff here rather than in the FAQ version. My thought is, if there is any discussion here, the end results can be gleaned and used to update the FAQ. The goal is keeping as much chatty evolution out of the FAQ as possible.

-- So, 1st question. Mark, you mention that after a few uses your gas-holding syringe might stick a little as it fills, and how to deal with that. So I would expect the same could happen as it empties. Have you noticed any glitches in the flow rate into the chamber from stiction as the D2 is being pulled out?

-- Not directly related to producing D2, you have two valves in the path between the storage syringe and the chamber. You mention the metering valve closest to the chamber has fine control. You mention the other is a medium flow valve (my words, I didn't check the video). I'm curious if this medium flow valve plays much part in the metering of the D2 into the chamber or is it more of an on/off and the finer metering valve does all the real control?

You know how you use them and how they interact. I'm asking based on what I think I would expect. Just curious.

-- In your video, there seem to be long rods/knobs on the two valves. I presume these are just extensions that you added. No problem, just might help the viewer understand what they are seeing if there was a comment in any text footnotes to the video.

-- It might also help the full story to mention what the two valves are (Swagelok SS-SS4 or something). No need in the video, just follow-up in the post.

-- *Yes, my last three are not directly related to PEM D2 production. I don't intend these to be critical, I thought it just might fill out the usage story a bit.

---------------------------
In 2018 I posted a message in the New User Chat forum about using these small PEM cells. Here's the link (still surviving) --
viewtopic.php?f=46&t=12567

At the time Richard wanted me to move it to a FAQ post. I intended to do that. But first
I wanted to put together a small humidity sensor and measure the H (or D) output to see if a small humidity filter in-line was worth the effort. I never did those tests so I never posted to a FAQ.

So maybe I should still tweak up my old post a bit and make it into an additional FAQ.

Commentariate: Should I do that? If I do, should I put it into Mark's (via Richard) FAQ message or should I make it a separate FAQ and reference Mark's?

----
Now, two key differences in what my old post put together, vs. Mark's simple, straightforward usage.
I added two small chambers on the O2/water side made from small syringes (no plunger, just cut off cylinders as small reservoirs). See pics in my linked post.

The first of these two add-on tubes connects as closely as possible to the bottom nub on the O2/water side. The plan is to initially fill with water/D2O to a level equal to the top of the PEM membrane. The idea is to provide a small external reservoir so the liquid level on the membrane drops slower as the liquid is converted to gasses.

The second tube is connected to the top O2 output on the PEM cell. This O2 gas is allowed to just escape. In operation I noticed that the O2 bubbles in the cell were pumping a small amount of liquid out of this port as they escaped. The purpose of this second tube is just to provide a place to capture any expelled liquid and let it drain back into the PEM chamber.

I am welcome to any comments and especially about me posting my old message as a FAQ and also if my two external small cylindrical chambers are worth the effort.
Rex Allers
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Mark Rowley
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Re: PEM Cell Deuterium / Setup and Operational Basics

Post by Mark Rowley »

Hi Rex and thanks for the compliments.

Regarding the first question:
Yes, I have noticed the plunger slightly surge forward during fusor operation. However, the needle valves appear to regulate flow in a way where such movement has no effect. I have directly observed zero movement on the vacuum gauge and no noticeable change in neutron production or Star luminosity during those instances. From my experience, the only negative issue of the sticky syringe is during the filling process.

Second question:
Yes, two valves with one being a fine adjustment SS-SS4 needle valve followed by a medium flow valve, which is then followed by the syringe input tubing. Surprisingly, the medium flow valve is the main point of adjustment followed by the SS-SS4. Quite honestly, I could probably loose the SS-SS4 and suffer no significant issues with gas flow adjustment. Typically, the SS4 is opened about 3 turns and left alone. But again, as we know all fusor designs and assemblages are different. For PEM cell D2 I didn’t want to get too much into the specifics of my system other than the universal need for purging that valved feed line.

Third Question:
The extensions are just lexan rods I put in place to make it easier to adjust from a standing position.

Rex, I like your original PEM cell build. Having a more elaborate system to provide a constant flow is quite interesting. Something along those lines would be good for a larger chambered system where a 100mL syringe would be consumed rather quickly.

Regarding the humidity, I haven’t noticed anything Earth shattering. If you recall, I built a cold trap last year that had mixed results but leaned in the direction of some improved neutron count. I’m now somewhat skeptical of those results as it was only used on the older 2.75” cross fusor. After building the current and slightly larger system, I’ve since realized the 2.75” lacked stability. The new system being stable enough to walk away from is more suitable to testing the cold trap. I may revisit that arrangement and compare findings with this new system.

Overall, my main focus is simplification on all fronts. I understand comparatively complex PEM cell arrangements can be built but for an FAQ I think simple and basic is good. It offers an encouraging starting point for the newbie.

Mark Rowley
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Richard Hull
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Re: PEM Cell Deuterium / Setup and Operational Basics

Post by Richard Hull »

This is all chatty stuff....But real stuff that totally belongs in the FAQ and not here. Again, this will sink ever deeper into the compost that no one, a year from now, will read!! Hell, the bastards barely touch the FAQS!! @#^%**(^@! Only the extremely rare bird digs into the old forum posts. Gems are lost in them, effectively. That is the reason I try to retrieve the best jewels like Mark's videos into the FAQs.

Chattiness in the FAQs by old boys with knowledge to contribute can be as chatty as they want. It must all be content based from knowledge or good questions from those out of their depths who have viewed all the videos and all the replies and still need answers. Only then should anyone ask a question or go chatty. I was totally amazed when Mark just plugged in the batteries in the original video?!?!! What? Where's the D2O? It was not covered at all! Thus I questioned. Mark went back to the video camera and did a first rate job of teaching how to prep the cell. I was made smarter for the question and now all others will be, too.

As of this moment I am thinking of pulling the above posts into the FAQ Chatty? Yes! Valuable to the FAQ? Yes!

Rex, should you pull together a decent FAQ related to your work, it should be a separate FAQ. Keep me in the loop.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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Mark Rowley
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Re: PEM Cell Deuterium / Setup and Operational Basics

Post by Mark Rowley »

Sounds good to me Richard

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Richard Hull
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Re: PEM Cell Deuterium / Setup and Operational Basics

Post by Richard Hull »

No more replies here of the above caliber. Make them to the true FAQ. Could I prevail on Mark and Rex to move their posts above to the FAQ via a reply. If I move them they would have my post avatar as I would just copy and paste. Rex first and then Mark so they are in a sensible order. Thanks

Frank, can you lock this thread?

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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