COVID-19 Printable PAPR (Powered Air Purifying Respirator)  

RE: COVID-19 Printable PAPR (Powered Air Purifying Respirator)

Posted by: @h-waibel

[...]  I continue to propose an alternative design that provides protection in an upward direction. That would mean some type of collar that supports an upward shield. This would also stay between the user and the aerosol source if the user turns the head (another natural protection response in case of splash). The "top mounted" solution presents a huge gap directly into the spray in this scenario.

Would a throat protector like those worn by hockey goalies be useful? They seem to allow good head movement while protecting from things flying in below. If the head is dropped, it forms a barrier yet still shields if the head is raised. If a flexible foil is used to tape this protector to a full shield, might it not provide superior protection from below? I'm thinking this would easily be added onto existing designs and be easy to produce.

RE: COVID-19 Printable PAPR (Powered Air Purifying Respirator)

More coverage above and below is better than no coverage. That rather pointedly illustrates why I am NOT going after face shield. It's simply incomplete protection compared to a sealed, positive pressure breathing environment.

The Wuhan corona virus on particles generated by even singing or talking are now known to be infectious. We already know the micro size aerosolized particles are a danger.

Use an N95 and face shield and all that will get by the shield. Only the N95 is giving you protection against the aerosolized particles. That would be fine if we actually had enough, good, proven, and WELL fitted N95's. We don't. I get issued one to use for as long as it doesn't visible appear damaged or soiled. We don't have a good way to sterilize them between uses other than ad hoc means like microwaving with a water tray beneath it, keeping it overnight in a paper bag to dry out, or wiping it with a bleach that damages the filter. Yes, that is what we're getting asked to trust.

So, a second layer of COMPLETE protection against micro-aerosols is needed in case that N95 fails. That is why I released the BS Halo PAPR. At the very least it will keep the N95 less contaminated. At the most likely, its filter will do better than the N95. It's rated for better than N95 filtration. Add to that the complete enclosure of the head and you're way ahead of just a face shield and separate mask.

The 3D printing community can make a huge advancement making high level PPE possible. Instead, I only see projects aimed at much more modest protection goal. Yes, a PAPR is a scary beast if you don't understand what you're doing. I've taken care of the design and testing part. Now, the even harder job is getting non-medical people to understand that a PAPR is possible (let alone what one is)

RE: COVID-19 Printable PAPR (Powered Air Purifying Respirator)

Posted by: @guy-k2

[...] The 3D printing community can make a huge advancement making high level PPE possible. Instead, I only see projects aimed at much more modest protection goal. Yes, a PAPR is a scary beast if you don't understand what you're doing. I've taken care of the design and testing part. Now, the even harder job is getting non-medical people to understand that a PAPR is possible (let alone what one is)

Guy, just to be clear: Are you suggesting that anything short of the full protection offered by your design is a waste of time and dangerous? I'm happily printing in accordance with the guidelines being provided by the local Masks for Docs slack group, but they're suggesting the NIH v3.1 visor design. If all of this is going to end up getting thrown away, I'd be equally happy printing clips and tags that are actually safe and usable. Word is that the "ear savers" are much appreciated to reduce chafing behind the ears from wearing masks. Any suggestions for community involvement?

RE: COVID-19 Printable PAPR (Powered Air Purifying Respirator)

Posted by: @bobstro

Guy, just to be clear: Are you suggesting that anything short of the full protection offered by your design is a waste of time and dangerous? 

RE: COVID-19 Printable PAPR (Powered Air Purifying Respirator)

To be fair, most medical groups would not believe a 3d printer enthusiast can make an effective PAPR with full head isolation. Tough enough for me, a medical doc, to explain why it possible and works.

Towards making the BS Halo PAPR easier to accept (without needing to understand), we're going to apply for FDA approval. It won't be granted in time for this peak, but we'll at least get the bureaucratic stuff under way.

Meanwhile, I keep forging forward so people can make usable units ASAP. United States 1st peak is going to be this month. 

RE: COVID-19 Printable PAPR (Powered Air Purifying Respirator)

Thanks for the clarification, Guy. There's a lot of confusion out there and I'm seeing a lot of hobbyist "improvements" that are of questionable use. The MFD group is trying to get everyone to standardize on one shield design (NIH v3.1) for ease of batch assembly and development of procedures.

I do wonder if there are also more mundane things we can be printing that are low value but high demand and hard to get such as clips, carabiners and the like.

If you get the PAPR to the point that an average home hobbyist can produce parts, please let me know and I'll bring it up to our local group and assist where I can. Thanks for all your efforts!

RE: COVID-19 Printable PAPR (Powered Air Purifying Respirator)

If you get the PAPR to the point that an average home hobbyist can produce parts, please let me know and I'll bring it up to our local group and assist where I can. 

Design is already at that point. We can already print the parts for use. My Prusa's are running 24/7 making them in PETG. A full setup is about a 12 hour job on my machines. Thankfully the frame and fan flange are reusable. The penetrators too, but not best practice. Can't push it much faster because thread geometry needs to be perfect. I'm also printing hotter than normal to get superior interlayer fusion.

(E3D 255C 1st, 260C subsequent)

(Slice with tungsten carbide nozzle 255C / 265)

We can make them now, but you also need places to understand and accept them. 

Main task now is getting organizations to realize that a good working PAPR is even possible. It's so radically different.

On the other hand, the look of absolute joy when a medical practitioner sees it working in front of them is amazing. They want one immediately. Bottom up acceptance is easy. Top down is harder. That's why I have contacted FDA.

Parts in production

Some shots of HALO parts being produced...

Halo PAPR in Production

RE: COVID-19 Printable PAPR (Powered Air Purifying Respirator)

Good Morning guy,

apologies for asking questions that might already be answered.

I did the first print of the gas supplied one just to save a bit of printing time. For me it seems to be on the small side as the split element touches the outer ring. Whereas for my partner it is way too loose.

I seem to remember that you mentioned different sizes of the halo. If so, where would I be able to find the files?

On another note, the contact surface with the wearers head seems rather small to me. To increase that and thus to spread the pressure on the forehead a bit more evenly do you think it might be a good idea to widen the frontal portion of the "spring" ring into a more triangular shape? It probably doesn't have to be as thick as the load bearing part of the ring. For the actual user I would also recommend using some sort of padding. The first thing that comes to my mind would be foam or hydrocolloid dressing. There is a lot of information floating around about people developing nasty pressure sores from wearing rubber band attached masks.

And the other question is more of a general understanding thing. I've seen the images of the fan version where you designed a completely flat and uninterrupted surface to attach the fan to. As far as I could find out, most fans blow in an axial direction. Where does the gas flow go, when the fan sits on that flat surface? Shouldn't it have holes? Where am I stupid here???

No response from my team colleagues about the potential to use your design here yet, but I will keep nagging.

Kia kaha! (stay strong in te reo māori)

Hansjoerg

RE: COVID-19 Printable PAPR (Powered Air Purifying Respirator)

Check the latest STL files on Thingivers and PrusaPrinters. Should find std and small size halos. These also have tapered contact areas to better distribute pressure. I agree that some padding would be nice. Could add more height, but the up/down contact angle would vary with head size quite a bit. Give a try with the tapers. They are definitely more comfortable.

Fan mount is now integrated with the halo. You don't have to mount a 51 mm blower, but it is quite a bit nicer to have more gas flow, but still have high level filtration via ventilator filter.

Blower fans have air exit out their side. Hence, no hole in mounting plate. I have fan outflow directed towards left of halo. I cannot recommend a tubaxial fan due to their relatively low static pressure capability

More detailed assembly instructions will be online later tonight at dozuki.

RE: COVID-19 Printable PAPR (Powered Air Purifying Respirator)

Blower fans, of course! hand->forehead...

Should have thought before writing.

Is there also a larger version in the making?

RE: COVID-19 Printable PAPR (Powered Air Purifying Respirator)

Here is a BS Halo with blower fan and fan flange installed. Bag penetrator 22mm fitting goes through bag and attaches to top of flange. Ventilator viral filter goes atop 22 mm fitting.

RE: COVID-19 Printable PAPR (Powered Air Purifying Respirator)

Packaged with its bag penetrator fittings (22 mm taper adapter, flutter valves,, valve deflectors). One tape and two valves are used. Packaged with extras so one set of penetrators can be sanitized while the other set is in use.

This will go into 65C soak for four hours before I distribute.

RE: COVID-19 Printable PAPR (Powered Air Purifying Respirator)

Is there also a larger version in the making?

Give me your forehead fore/aft and lateral dimensions. I can model one up to suit you if last night's tapered std model is too small.

RE: COVID-19 Printable PAPR (Powered Air Purifying Respirator)

Added more complete wiring and assembly instructions to the guide. https://bunnyscience.dozuki.com/Guide/Bunny+Science+HALO+Respirator+(Buildable+PAPR)/4#s127

For makers, it is a ridiculously trivial build - which is part of the point. Supply more complete protection, but with easy build.

RE: COVID-19 Printable PAPR (Powered Air Purifying Respirator)

This might be the ultimate choice for PPE in Canada as 3M has been asked (told?) to not ship N95 masks to Canada. Just on the news! This after a shipment of masks disappeared. Nothing like a pandemic to bring out the "best" in people. Fortunately there a people like Guy and all the countless volunteers that are doing what they can to protect our front line health workers.

Does Halo require the fan?

RE: COVID-19 Printable PAPR (Powered Air Purifying Respirator)

Does Halo require the fan?

For most uses, yes. There must be a source of clean airfow. The fan is needed to pull air in through the ventilator viral filter and deliver it into bag with some pressure. 

It can run without a fan, but only with a compressed oxygen or breathing air source. That's fine if one doesn't need to move - a narrow usage case.

Fan PAPR configuration is definitely the way to go.

Currently trying to making it more comfortable with halo size adjustment and over top of head strap. Would be great if I can get the comfort part ok for 12+ hours of continual wear. Current halo design gets uncomfortable across forehead about three hours.

RE: COVID-19 Printable PAPR (Powered Air Purifying Respirator)

Kia ora guy,

now that the print with the fan attachment has finished over night I came to realize that I am obviously too thick headed for the design, or that I am trying to wear it wrongly.

On the fan version, the fan attachment blocks the flexible prongs to extend enough for my head to fit and the plate touches my forehead. Looking at how the thing sits on the build plate I don't see many options to get it any bigger. It seems the are a few tiny mm possible by moving the fan plate outwards thus generating more space inside the ring. But I doubt this would give enough room for the inner ring to expand far enough. The only solution I see to get the whole thing bigger would be going back to the previous design, where ring and fan plate were to separate pieces.

Would you be willing to share original CAD files so that I could tinker myself? If they can be used with Fusion360.

RE: COVID-19 Printable PAPR (Powered Air Purifying Respirator)

Don't struggle too more with the fitment. I'm completely redoing the mounting system to permit full size adjustment and shift weight from front to top. Working on the halo portion's CAD. Here is a mockup I used to check fit on some different sized heads.

Rubber band gives headband its "give." The mockup is much more comfortable and should fit a larger range of users.

Not pretty yet, but you will get the idea. Should have the new revision up by tomorrow.