The Covid-19 Steampunk Hat Thread

[J. Wilhelm]

So as I promised on another thread, I'm starting a new project for a combination visor /respirator that will protect the user from inhaling particles laden with the Sars Cov 2 virus.

I figure that I've delayed this project long enough, perhaps because I made a very successful respirator mask that's helped me stay healthy so far, in spite of the fact that I haven't stopped working an single week since the middle of March and worse I have to spend up to one hour on the bus to get to work.

Sadly the situation in the United States is taking a bad turn. My city, Austin has now been declared to have the highest infection rate, although we don't have the largest number of cases, I think that would be Houston. The cause for that spike is said to be reopening the businesses too soon, on particular bars /pubs and restaurants with dining tables. Texas Arizona and California are all in dire straights as I write this post.

Also, I have received mixed news about my employment. My boss/proprietor of the business couldn't take the heat and has decided to sell the business, to a person who by providence or nativité decided to purchase all the shops in our former little franchise (about 4 stores in all). Luckily for me, all front of the house personnel get to keep their jobs, in my case that means this is the 4th time I've survived the business downsizing since 2016 (the business spilt first and one half was purchased by my current boss - the new owner will bring all of the shops back together again - presumably under a new name). Unfortunately all of the back of the house personnel lost their job, the whole lot, in order to concentrate production to a central plant, and have all the shops be pickup locations - efficiency, I believe is the reason. I don't know how much money I will earn starting on the 17th of this month, all I know is that I'm employed.

So.... I don't know how much disposable money I will have in the near future. I remain hopeful it'll be more than the reduced pay I've been living on for the last 3 months. But I just don't know. Unfortunately I have sunk quite a bit of effort and some money into the Victorian Boombox Mk III. But that is no excuse for not building a device that may very well save my life or that of others.

Consequently I'm going to slow (not stop) the Boombox project for now and rush into making the new mask while I still have a little money. The mask may also be a new source of work for me - I'm crazy like that, but I've done it before, so there's no reason not to try. Alright. Introduction aside, this is what the project will be: a faceplate which may include a hat in which filtered and cooled /heated air is circulated, most focusing on the face, and if possible the scalp, and the neck.

Why so ambitious? Because the summer conditions faced in the American Southwest are extreme. So are the conditions on the whole Northern half of the country during winter. Summer temperature rises above 35 Celsius and peaks near 45 C by August. People have to wear cloth and filtered masks in the heat, sweating profusely. Sweat will run down your face on to your eyes, through your mask into your nose and mouth and you will literally taste sweat laden with virus. This observation is made from experience at my job and running to catch the bus to go to my job.

The mask respirator I made before held brilliantly under those conditions, but I still suffer from sweat running down my eyes, and people can neither see my face or hear my speech clearly. A transparent visor could fix all of those problems, and serve to alleviate the heat or cold effects. The human head is the largest consumer /radiator of heat in the body, so it makes sense that cooling the head in summer and heating it in winter would be the most efficient way to help temperature regulation in the body. That's why people wear hats! Artificial climate has done away with the custom to wear hats for all occasions. As Steampunks we should know that.

My plan is roughly as follows; First, I will use a plastic helmet as a prototype first, which could later be transformed into a Stetson hat (favoured by the locals), a trilby, a top hat, a bowler and quite likely a pith helmet or pickelhaube. So this is a very versatile piece. Second, there will be a plastic visor for the face. The visor will be sealed in such a manner that it's airtight about the face, with filtered air inlets and outlets. You don't do anyone any favours if you protect yourself but by means of a valve or such you breathe your germs onto others - that is in fact the defining characteristic of Covid-19 over any long of application requiring a respirator, so 3M style masks are useless in the face of this requirement.

Third, if at all possible there will be air circulation above the scalp but that is not a major goal, same with the neck. Large arteries and veins run through the neck to feed the brain, and active cooling methods such as Peltier devices have been used in the past (eg The Sharper Image) to make "cooling scarves" aimed at extracting heat from the neck. Because of that I think that the best location for a cooling device would be the neck, with air tubing directed to the face shield. A unit with fans and filters could be worn around the neck.

Fourth, because of safety reasons you may not want to wear a battery around your neck. Presumably this would be a lithium ion rechargeable battery. The belt would probably be the best location. Using the belt and the neck to carry components of the device will keep the hat light enough to be comfortable.

So this is what I purchased today: The starting point is a $6 white 3M construction helmet and a $12 polycarbonate faceshield. O like these components because they're easily replaceable, and the faceshield is flexible and very clear.

The helmet can be transformed into any kind of hatThe faceshield or visor is attached to the visor of the helmet
And there will be a method to seal the very flexible faceshield around the cheeks and chin of the wearer

I don't know at what speed I will make progress. This is a prototyping process, same as the Boombox. Peltier devices by themselves seem inexpensive enough, especially since the minimum area to be cooled is just the human face. The single biggest obstacle will be the power supply, but I figure that if the "cooling scarf" could be run from a battery, so could one or two Peltier elements. I'm figuring the fan assembly to be some sort of cylinder on the back of the neck around the peltier device. Tubing will run to the faceshield, in a Star Wars Stormtrooper helmet fashion.

Let's see what it I can do. I'd like to have fun and turn it into some Steampunk hat while I'm at it... Any suggestions?

At remain at your service,

Adm. J. Wilhelm

[MWBailey]

Ihave no hope of producing anything much in the near term, but I was thinking the other day about just how one would go about building an air-concentrating respirator unit, and whether  fan or accordion  drive would be preferable; period-wise (meaning steampunk/Victorian vs. diesel/modern), a concertina-like bellows would seem to me to be more of the Victorian style. Might even be easier to acquire materials for the concertina bellows vs. the fan. Just a thought.

[J. Wilhelm]

Ihave no hope of producing anything much in the near term, but I was thinking the other day about just how one would go about building an air-concentrating respirator unit, and whether  fan or accordion  drive would be preferable; period-wise (meaning steampunk/Victorian vs. diesel/modern), a concertina-like bellows would seem to me to be more of the Victorian style. Might even be easier to acquire materials for the concertina bellows vs. the fan. Just a thought.

That's a great idea, and one of the issues that I have to deal with is the speed at which air is taken into the face shield.

I'm going to have to decide how to ventilate. You'd don't want a very powerful fan if all you want to do is to blow air in front of your face. Similarly, the cooling required is very small. The bellows is an interesting proposal to control that flow. I would need to set up a cam-shaft type of arrangement to an electric motor to operate the bellows. What I can tell you, as far as difficulty in finding fans, is that there are very small fans readily available because they're used for computer CPU heatsinks. I have a couple of dead motherboards and a couple of CPU fans, one standard, and one very tiny fan for a mini ITX Vía CPU.

For any mask the faster air moves in, the more likely that viral particles will penetrarte through the layers of the filter. That's why my respirator has a wide "mouth." The idea is that it takes very little force to draw air in. In contrast respirators with valves feel very restricted, and you have to inhale forcefully. The likelihood of particles penetrating is much higher unless their filters are very dense (which they are).

If a bellows can do ventilation better, then it's on the table for consideration. The only issue is that I need to take a look at the energy consumption. How much energy is required to squeeze an accordeon? And how much to run a very small fan with ball bearings?

I will be looking at doing an energy budget and the smaller the area to ventilate, the smaller the cooling requirement and the size of the fan. On the other hand, for a Peltier device to work, you need to have a fan, and there are kits which include the fan. I may have to use the Peltier device with a bypass feature to make sure I'm not blowing too much air in front of your face. Also I may want to look at having a positive pressure differential in the mask, even if I have a filtered exhaust (you need one to protect people around you).

[MWBailey]

Ihave no hope of producing anything much in the near term, but I was thinking the other day about just how one would go about building an air-concentrating respirator unit, and whether  fan or accordion  drive would be preferable; period-wise (meaning steampunk/Victorian vs. diesel/modern), a concertina-like bellows would seem to me to be more of the Victorian style. Might even be easier to acquire materials for the concertina bellows vs. the fan. Just a thought.

That's a great idea, and one of the issues that I have to deal with is the speed at which air is taken into the face shield.

I'm going to have to decide how to ventilate. You'd don't want a very powerful fan if all you want to do is to blow air in front of your face. Similarly, the cooling required is very small. The bellows is an interesting proposal to control that flow. I would need to set up a cam-shaft type of arrangement to an electric motor to operate the bellows. What I can tell you, as far as difficulty in finding fans, is that there are very small fans readily available because they're used for computer CPU heatsinks. I have a couple of dead motherboards and a couple of CPU fans, one standard, and one very tiny fan for a mini ITX Vía CPU.

For any mask the faster air moves in, the more likely that viral particles will penetrarte through the layers of the filter. That's why my respirator has a wide "mouth." The idea is that it takes very little force to draw air in. In contrast respirators with valves feel very restricted, and you have to inhale forcefully. The likelihood of particles penetrating is much higher unless their filters are very dense (which they are).

If a bellows can do ventilation better, then it's on the table for consideration. The only issue is that I need to take a look at the energy consumption. How much energy is required to squeeze an accordeon? And how much to run a very small fan with ball bearings?

I will be looking at doing an energy budget and the smaller the area to ventilate, the smaller the cooling requirement and the size of the fan. On the other hand, for a Peltier device to work, you need to have a fan, and there are kits which include the fan. I may have to use the Peltier device with a bypass feature to make sure I'm not blowing too much air in front of your face. Also I may want to look at having a positive pressure differential in the mask, even if I have a filtered exhaust (you need one to protect people around you).

The idea that occured to me last night (kept me up a while thinking about it) was a sort of elastic-squeezed airbag or perhaps secondary bagpipe bellows arrangement, a la Uilleann bagpipes (again following a quasi-Victorian mindset) but with a spring or an elastic element of some kind attached to squeeze the bag instead of using one's arm, for holding the air taken in while also providing impetus for slow outflow to the face, and thus regulating airflow into the mask; perhaps a smaller, slightly-perforated bladder surrounded by filtering material with possibly embedded dessicant (to reduce the occurrence of droplets or external soaking) for the exhaust port.

I realize that I'm just sort of pipedreaming, but maybe I'm also giving you useful ideas. Hope springs eternal.

[J. Wilhelm]

I welcome all ideas. Nothing is out of reach until I have got something tangible in my hands as and have a feel for the problems at hand. The only warning, is that because I'm making a practical device, it will always be the simplest option!

Pipe dream? Well you know there will be pipes, right 

[Gregor]

Hi!

I am working on a similar project though trying to make it more leather based (nose and mouth mask) with goggles. Currently hacking at incoming cooling air filtered in and outlet through another filter to not only address the CoVid virus (mostly in the exhaust) but dust and fumes (input).

A quick toot through the welding helmet respirators interwebs presents all sorts of ideas and set-ups.

interesting, but biggish bucks - 3M Airstream Headgear-Mounted Powered Air Purifying Respirator (PAPR) System AS-400LBC on Amazon and elsewhere.

My gear from a previous job had a belt mounted battery fan (almost a compressor) respirator, the hoses up to my head, a welding, uhhh, pre-helmet - really a clear mask that was like a clear face-dome, a welding rest of the mask opaque plastic with the eye-shield glass (helmet - again I don't know why they call them welding helmets, it either protects your head when it is up or your face and eyes when it is down), and a neck-wrap that acted like a gasket to keep the fumes from getting in under the rig (I didn't like the hood).   They are much nicer now.

I expected to buy some of the components like the tube-fan and a cooler.  They are very expensive.  Very.  Expensive.   Sooo I am working on my own now and am probably making it way more complex than needed.

I will be watching your build, and will post if anything I am working on might be of help in this, when I get my workshop back next week.

OK - off to eat more tuna, I need the cans for filter housing. Someone suggested I use cat-food cans, but I like the people tuna better than the cat-food tuna. . . . .   Cheers! - g

[J. Wilhelm]

Hi!

I am working on a similar project though trying to make it more leather based (nose and mouth mask) with goggles. Currently hacking at incoming cooling air filtered in and outlet through another filter to not only address the CoVid virus (mostly in the exhaust) but dust and fumes (input).

A quick toot through the welding helmet respirators interwebs presents all sorts of ideas and set-ups.

interesting, but biggish bucks - 3M Airstream Headgear-Mounted Powered Air Purifying Respirator (PAPR) System AS-400LBC on Amazon and elsewhere.

My gear from a previous job had a belt mounted battery fan (almost a compressor) respirator, the hoses up to my head, a welding, uhhh, pre-helmet - really a clear mask that was like a clear face-dome, a welding rest of the mask opaque plastic with the eye-shield glass (helmet - again I don't know why they call them welding helmets, it either protects your head when it is up or your face and eyes when it is down), and a neck-wrap that acted like a gasket to keep the fumes from getting in under the rig (I didn't like the hood).   They are much nicer now.

I expected to buy some of the components like the tube-fan and a cooler.  They are very expensive.  Very.  Expensive.   Sooo I am working on my own now and am probably making it way more complex than needed.

I will be watching your build, and will post if anything I am working on might be of help in this, when I get my workshop back next week.

OK - off to eat more tuna, I need the cans for filter housing. Someone suggested I use cat-food cans, but I like the people tuna better than the cat-food tuna. . . . .   Cheers! - g

Hello! Yes, today actually I'll begin the prototyping. My take on it is addressing one problem I still have with the respirator I built (see COVID thread). Basically the weather is so hot and humid that your face is a river delta of sweat streams. Besides the obvious discomfort, there is a risk of getting infected by way of sweat into the eyes nose and mouth. It's not uncommon for me to taste my own sweat with or without the mask when you're walking at least a mile from the bus stop at 100 F. My eyes will sting and close shut from the sweat, and I'm unable to touch my face due to the COVID protocols.

So in response my aim is to cool the face, and cover it completely so you don't have to deal with that. Otherwise my respirator - just a simple muzzle type mask with a WWI style canister in front is the hands-down winner among the respirators I tried. But people still can't see my face and they have a hard time understanding what I say. This is a problem at work, and, due to the location and nature of of my job I will not just wear a cloth mask. It's not enough. I also work at a place with no air conditioning. In summer it's just as hot inside. And touching your face is definitely forbidden!

My approach to the problem is to create a rigid or semi-rigid structure that adapts to the shape of your face first, and then part from there. That's the approach I took with the respirator. I also want it to be as light as possible. I've seen the professional respirator visors out there, and frankly they're way too big to be practical. With the technology we have today we should be able to wear much lighter gear. So I'll leave the aesthetics in the back burner for the moment and concentrate on the practicality of it. The Steampunk part will come later...

[J. Wilhelm]

I start with something simple. Quaint, even. This, believe it or not is the most important step. The mask has to fit your face. Using gobs of rubber material to "universally adapt" is the wrong approach. In my experience, the 3M respirator has a fantastic rubber design to fit over the nose and mouth, and when you go out on the heat and try to wear it, the mask slides all over your face, like if you had plastered butter all over your face. When I made my home grown respirator before I tried the 3M respirator, I had used a steel ring which I bent over my face to fit the shape of my nose and chin. The steel ring can be harsh on the nose bridge, but it adapted well and does not slide off your face with the heat.

The only problem with the steel ring is that it only fits my face. The ring is not soft enough to bend to the shape of the nose. Thinking about that I'm choosing a hybrid method, where a steel ring is used to give the initial shape of the mask, but it will be bendable so you can open up or tighten the mask to fit your face. In many ways, the visor's steel ring is much simpler because the shape of a human face is simple over the forehead, the sides of the face and your chin. I figure a rubber gasket or hose over a stiff wire ring will be flexible enough to adapt, yet rigid enough to bend the Plastic shield.

So I used a thin copper wire to make a stencil of my shape right over my eyebrows, and over my chin, below my mouth. Some space is needed off your face to fit the length of your nose.

When you compare to the plastic face shield (also made by 3M), you can see how much bigger those face shields are compared to your face. I will need to do some cutting, but I don't think I need to cut the sides or the bottom. The lower part of the plastic shield is nicely shaped like your chin. Only the top part of the shield needs to be cut to size.

The rubber comes from a closed cell soft insulation tube for water pipes

The wire frame will be made from 9 gauge galvanized steel wire. Stiff enough to force the plastic shield in place, and flexible enough to be molded by your hand.

Besides cutting, holes will need to be punched to allow air in and out of the visor. As you can see the volume between the visor and your face is very small. Hence cooling and air circulation requirements will be small. Cooling off your scalp or neck will be treated differently.

[J. Wilhelm]

SNIP

I expected to buy some of the components like the tube-fan and a cooler.  They are very expensive.  Very.  Expensive.   Sooo I am working on my own now and am probably making it way more complex than needed.

SNIP

I got some ideas about that. You see there are many similar applications out there. If you look for human/ medical grade stuff, you may find it's too expensive. The ventilation need is small, really, if you think about how much air you breathe per minute. The inlets outlets can take air very slowly with big filters (its best that way), but en route to the mask, you can make the air go as fast as you want, just being diffused inside the mask before you breathe it, hence you can reduce the size of the tubes going into the mask. It's just fluid mechanics.

SNIP
OK - off to eat more tuna, I need the cans for filter housing. Someone suggested I use cat-food cans, but I like the people tuna better than the cat-food tuna. . . . .   Cheers! - g

I don't know, man. The way things are going, those cat tuna cans will be like a delicacy in the near future. I'm thinking of that scene in Mad Max..

Mad Max 2 Dog food scene

[J. Wilhelm]

So using the 9 gauge wire and the pipe insulation I made a frame gasket for the plastic shield. It was remarkably easy to make. The wire however may not be strong enough to hold the shape under the tension of the plastic shield. So I may have to add a couple of wires or add flat metal bars at the top and bottom of the frame gasket

Dimensionally, the gasket seems to be just the right diameter and looks like it may even allow you to wear spectacles with no problem. The closed cell rubber is very soft and takes well to bring glued with cyanoacrylate. The only thing is that, aesthetically, it's looking à little chunky. It'll be very hard to find a better solution though, unless I could get hold of the same foam in white

[J. Wilhelm]

I just tried on my face, and I have a few observations:

1.The field of view is incredible. I hadn't noticed how much of your field of view is blocked by even a simple cloth mask. This visor takes away any and all visual discomfort.

2. The gasket is very comfortable. As it is, the gasket is so far behind your field of view, that it easily fits over the spectacle "arms". Unless you're wearing aviator style or oversize spectacles, there will be no problem with your eyewear.

3. The gasket is thick enough for every single purpose, unfortunately the tip of my nose is touching the plastic shield. I can live with it, though, it barely touched the plastic. But people who have longer noses, or lie a lot may need a gasket with a greater diameter.

4. I may have to trim both the top and bottom of the shield. It's looking a bit too large. I'll have to figure out how to do it, or live with the excess plastic.

5. It does need quite a bit of force to mold the clear shield. I think a flat aluminium strip glued to the shield might do the trick.

[J. Wilhelm]

I've attached the plastic shield to the rubber gasket. The mask looks a mess at the moment, because I didn't choose to use a silicone based sealant in black color. The backsside looks a lot more "professional"  , but the front will need some aesthetic help. Which might be fine because I still need two metal bands to help the plastic shield tighten it's curve. There might be paint or two aluminum bars coveringthe  top and bottom of the shield. (brass would be nicer, eh?).

I used white latex glue for two reasons. First there's a lot of imperfections in the gap between the gasket and the polycarbonate shield. The white paste allows me to see all the imperfections and seal accordingly. Second, it's very difficult not to smear the polycarbonate with sealer. It's much harder to cleanup if you need a mineral solvent, because that might cloud the plastic shield. Latex glue can be cleaned with water.

In fact that happened a bit when I used a couple of cyanoacrylate drops to pin the gasket to the shield first. Cyanoacrylate has this property where in a few minutes after drying it frosts any nearby plastic surface. Once I pinned the gasket, I used masking tape to hold the mask in shape (like the string in a bow) and then I used latex glue. Regardless it's nigh impossible to not scratch the polycarbonate which is very soft. To remove all the residue I had to use Formula 409 to avoid scratching the plastic too badly. It still got scratches but it's passable

There will be a need for trimming the polycarbonate - you can see how much from the pictures. Whatever decoration I use will depend on the context. For practicality I would have preferred a mirror surface in black. I now realize from the gasket that it looks too "chunky." I then though that white might work, but I also think it'll make the face shield look like a plastic helmet (astronaut helmet). One alternative is to use gold foil tape or silver foil tape. Metal colours will acquire a shine that mimics their surroundings and therefore will not look so obtrusive... Or maybe use a light polarising filter for a good Daft Punk effect? 

 Any suggestions?

[Hektor Plasm]

My apologies, but I felt that this marvellous creation had a place in this discussion:-



It is entirely suitable for delicate eyes..   

HP

[J. Wilhelm]

My apologies, but I felt that this marvellous creation had a place in this discussion:-



It is entirely suitable for delicate eyes..  

HP

Ha ha ha! That is awesome! And he picked a fancy one in chrome, I see ! Mopar, or Ford, perhaps?

[SeVeNeVeS]

Then there is always this design, (Mad Max) 

[J. Wilhelm]

Then there is always this design, (Mad Max) 

That potentially might be closer to Mr. Gregory's design, though... Withouttthe death grin. I need to not scare the customers away, though.

[Gregor]

LOL!

Yes, it does lean a little bit closer to my design, the teeth though, I dunno,  but for wimsey - I might do something like that  then put braces or a retainer-clip on them.

 Hektor P's photo of the man with the auto air-cleaner hat.  Beauty-full.   Maybe I will take my cat-food can filters and put them on the side of my head, like a maniacal Princess Lea headphone-hairdo thing.

I like the gasket so far, your patience is far better than mine.  I would be more prone to put a bead of expanda-foam insulation around my face, hold the shield in place, wait for the expansion and call it a day.
Now that I see it I understand it better.  Originally I was picturing something more like a scuba-mask set-up, this looks much more interesting and the end product should be pretty impressive.
     Maybe flock some crushed velvet on the face-touching part?   lol
For the scratches and fogging,  do you think the stuff people use to re-generate their car headlight plastic lenses might work?  I don't know if that is some chemical action, or mechanical like micro-polishing.

Anyways - Super Work! - Carry on . . .carry on     -g

[J. Wilhelm]

LOL!

Yes, it does lean a little bit closer to my design, the teeth though, I dunno,  but for wimsey - I might do something like that  then put braces or a retainer-clip on them.

 Hektor P's photo of the man with the auto air-cleaner hat.  Beauty-full.   Maybe I will take my cat-food can filters and put them on the side of my head, like a maniacal Princess Lea headphone-hairdo thing.

I like the gasket so far, your patience is far better than mine.  I would be more prone to put a bead of expanda-foam insulation around my face, hold the shield in place, wait for the expansion and call it a day.
Now that I see it I understand it better.  Originally I was picturing something more like a scuba-mask set-up, this looks much more interesting and the end product should be pretty impressive.
     Maybe flock some crushed velvet on the face-touching part?   lol
For the scratches and fogging,  do you think the stuff people use to re-generate their car headlight plastic lenses might work?  I don't know if that is some chemical action, or mechanical like micro-polishing.

Anyways - Super Work! - Carry on . . .carry on     -g

Thank you, but I'm afraid my mask won't look as cool as this varnisher's respirator and scooba dive mask... But I'm working on a similar concept.

I think, actually that the gold mask in the Daft Punk set is actually the right one for walking in bad weather    For years I was imagining wearing a motorcyclehhelmet. Since I have to walk for miles, even years before COVID 19, I was thinking of a way to deal with winter cold and rain, particularly freezing weather with precipitation, which I have done with nothing but a cap on my head.

For indoors, the face mask types above should suffice. One year ago I would have told you that wearing something like this or a helmet in public would be ridiculous. But now I find that after the pandemic hit people are very accepting of different looks and devices like my mask. I get asked 2-3 times a week where I got my respirator.

***

BTW I like your Princess Leia bun-respirator idea. Might as well double as headphones!   And I've been thinking about a Darth Vader respirator mask. Maybe with a triangular filter. We should get together and make a Star Wars themed set of masks   Though I bet many people are doing that right now.

***

No the neoprene foam should not get anywhere close to your face, nor any other part of the body.   I've used the stuff in the past to rebuild a broken plastic bumper and spoiler on a car for which I couldn't find replacement parts (1989 Ford Escort) and which I rebuilt and painted over the space of 2 years before I lost it to a bad engine block 6 years ago (it was my college car  )

Actually the rubber very much looks like thin leather over soft foam. I couldn't ask for a better material.

***

I might need optical grade compound to get the scratches out though. I'm not sure about the car stuff, though I indeed have bought and used a kit in the past (for the same Ford Escort)-o ended up buying new headlamp covers, because it could not get rid of internal cracks. The secret was a foam wheel impregnated with superfine polishing powder. If I get hold of one I might try it though.

For the moment the scratches are not too bad. It just bothers me that they used such a soft material..

[J. Wilhelm]

Ihave no hope of producing anything much in the near term, but I was thinking the other day about just how one would go about building an air-concentrating respirator unit, and whether  fan or accordion  drive would be preferable; period-wise (meaning steampunk/Victorian vs. diesel/modern), a concertina-like bellows would seem to me to be more of the Victorian style. Might even be easier to acquire materials for the concertina bellows vs. the fan. Just a thought.

SNIP

My gear from a previous job had a belt mounted battery fan (almost a compressor) respirator, the hoses up to my head, a welding, uhhh, pre-helmet - really a clear mask that was like a clear face-dome...

SNIP

I expected to buy some of the components like the tube-fan and a cooler.  They are very expensive.  Very.  Expensive.   Sooo I am working on my own now and am probably making it way more complex than needed.

SNIP

Let's talk about ventilation and cooling...

I've been spending some time doing practical research on Peltier devices.  Let's say that I'm not impressed with the thermodynamic efficiency of the TEC devices. For a 4 x 4 square element, you can get a fantastic temperature differential of 30 Celsius, or more, but only at a very high cost in power, usually around 50 W and 3-5 amperes of current for one element. 5 amperes may be practical for refrigerators, but it's awfully high for a battery, not suitable for a portable device, so I'm not sure it makes any sense to go down that route.

Here's a video on a the subject...

https://www.youtube.com/watch?v=0xY06PT5JDE

The issue for me is that I have to cool a very small volume in front of my face or at the most my whole head under a helmet, and I also have to provide ventilation. Proper heat sink and insulation, plus fan ventilation will mean my TEC device would be prohibitively large and heavy

As an engineer versed in thermodynamics, and more so as an aerospace engineer, I knew that there were other thermodynamic cycles that were far more efficient, including refrigeration cycles that are never used because on the surface they have a very low efficiency compared to those that involve evaporation of liquids. One such example is something known as the Bell-Coleman Cycle, which basically involves only compressing and expanding air, without a phase change from liquid to gas and vice versa.

https://www.ques10.com/p/38512/bell-coleman-cycle-1/

The Bell-Coleman Cycle is for all practical purposes an inverted Brayton Cycle, which is the cycle used for aircraft turbine engines. If you have ever traveled by airplane, then you know both cycles. The Brayton Cycle provides thrust for the airplane and the Bell-Colman Cycle is how you have air conditioning in the cabin. Bleed air from the compressor in the airplane's engines is taken and piped into the cabin, and when the gas is expanded by simply by releasing it at the nozzle, the expansion makes it cool down! The advantage of this system is that it performs two steps at once: It produces ventilation and cooling at the same time on location, without the need for wires or remote control. The disadvantage is that it has a very low efficiency compared to the A/C in your home or car, but even then the efficiency is many times higher than the efficiency of a Peltier device.

The Bell-Coleman Refrigeration Cycle

The first thing that popped into my mind was Gregor's mention of a compressor-like device on a 3-M helmet type respirator. My guess is that the device actually WAS a compressor. The pump could have any number of shapes like a rotary axial or radial compressor, but in any case, if you can compress the air and just release it, then automatically you'll get cooling. Remember, my cooling needs are very quaint. I just need to cool my face.

If said device produces a loud buzzing sound, then more likely than not it utilizes a small rubber bellows as a compressor, which reminds me of Mr. Bailey's suggestion for a bellows. Good call, Mr. Bailey! The only thing is that the motor will me more akin to a linear motor such as the ones you fond in electric razors, tattoo pens, and aquarium air pumps.

t just happens I have such a small device in my arsenal, a small 1.5 W aquarium air pump. Unfortunatley it is directly driven by 125 VAC 60Hz mains power (not even a transformer in sight). Could something like this even work in 40 Celsius weather? It depends. So I ran one and took a look inside...

A small 1.5 W aquarium air pump

My first impression of the air pump is that it's probably not enough to provide ventilation, or maybe it can, but at this size it's barely enough. The unit is noisy and vibrates a lot. The compression is realized by a microscopic bellows attached to a tattoo-pen sized linear motor. But one thing that stood out is that the faint stream of air coming out of the nozzle *definitely* is cooler than the ambient air. Cold, even to my lips. For a volume as small as the space between my face and the shield there might be enough cooling. It's just a matter of trying it out in real world conditions before I move to the filtering stage.

[J. Wilhelm]

I'm currently trying to size the pump to get the air properties I want. As an aeronautical major, this is wholy under my jurisdiction. One way to do a very rough estimate, regardless of size is to ignore viscosity for a second and use Bernoulli's Equation to determine the expansion of the air from the source (pump or tank).

Bernoulli's Equation is the simplest way to account for pressure as well as the air expands. For most purposes you may assume that when air speeds up it expands, lowering the pressure and the temperature locally.

So we have Bernoulli's Equation (ignoring potential energy, because there's not much height change involved)

p₁ + ½ϱ₁v₁ = p₂ + ½ϱ₂v₂

Where p is the local static pressure, ϱ is the density of the Air, and v is the local speed of the AIR. The subscript 1 denotes the stagnation chamber (tank or pump inlet) and 2 denotes the air outlet.

And then we have the Ideal Gas Law, again keeping things simple,

P = ϱRT

Where T is the local temperature in Kelvins and R is the specific gas constant, in this case for air, R=287 287 J/kg·K, if you use kilograms for density and Pascals (Pa) for pressure units.

Combining the above and noting I only care about temperature differences, and that I may assume the speed at the pump inlet or stagnation chamber is zero - and noting that Bernoulli ignores viscosity (which matters if the pipe is very thin - will be addressed later) and ignores any heat injected and entropy produced by a working pump, then we have the simple expression

V₂=√(2RΔT)

Where ΔT= T₁-T₂, the temperature difference you want., and √ is the square root operator.

I will assume that a a drop in temperature from 45 Celsius to 22 Celsius is enough to pass in front of your face - that may not be enough to cool you off, but just to keep face cool enough. So let's say a temperature drop of 23 Celsius.. Since one Kelvin drop in temperature is the same as 1 Celsius drop in temperature, and plugging numbers in, I get an outlet air speed of 114 m/s or 410 km/hr.

Before you jump from your seat and say   "whoa" that's faster than a hurricane" you need to understand that when it comes to moving air in pipes, airspeed can be much higher than you think for everyday machines, such as air pumps for tires and such. To give you an every day example, consider a compressed air can to dust-off computer parts. Few people realize that as the air (which in that case is nitrous oxide) leaves the nozzle, it's actually travelling at Mach 1, the speed of sound.

Per Bernoulli's Equation above, which is valid as it is isentropic expansion of a gas, the pressure differential between the can and the ambient air and the opening of the nozzle is small enough, that the nitrous oxide gets accelerated to Mach 1. It can't be any faster at the nozzle because at that speed there are strong changes in the behavior of the gas, such that it requires the nozzle to have a bell shape, opening in the direction of the air, like the nozzles of a rocket. Without a diverging nozzle, the air at the outlet is stuck at Mach 1, regardless of the pressure inside the can. We say that the nozzle is "choked."

So you see accelerating the air to 410 km /hr, equivalently 114 m/s is only about ⅓ of the speed of sound, which is 343 m/s, or my pipes need to push air to Mach 0.33. This is entirely doable. I just need to figure out what size of pump and if I need to build a stagnation chamber (tank) to go along with it. Most likely I won't want the pump to be operating all the time, and instead the pump will store the air in a tank and turn on and off as needed.

I'll come back with more results later...

[Prof Marvel]

Sooooo

If you spray your face with canned air...
and it weighs the same as a duck ...

prf marvel

[J. Wilhelm]

Sooooo

If you spray your face with canned air...
and it weighs the same as a duck ...

prf marvel

Then a duck must weigh the same as the six-pack of beer you drank in 15 minutes. I don't recommend using a  can of "air," unless that is only used for refrigerant in a separate closed loop.

[J. Wilhelm]

Latest suggestions by Dr. Fauci in the United States are now extending protection for the eyes as well. I can only imagine that the statistical risk of infection is increasing. Previously, I had heard that infection though the eyes was much less likely. I need to push this project as fast as possible.

ABC News: Dr. Fauci: Wear goggles or eye shields to prevent spread of COVID-19; flu vaccine a must.
https://abcnews.go.com/US/dr-fauci-wear-goggles-eye-shields-prevent-spread/story?id=72059055

[SeVeNeVeS]

Latest suggestions by Dr. Fauci in the United States are now extending protection for the eyes as well.

I said that back in April, Good to know the people in the know are keeping up with us plebs, lambs due for the slaughter. 

Everyone is banging on about masks, what about eye protection? Tear ducts lead to the nose and therefore the throat, therefore the respiratory tract. Just saying.......What do I know?, I hit stuff with hammers for a living

[J. Wilhelm]

Latest suggestions by Dr. Fauci in the United States are now extending protection for the eyes as well.

I said that back in April, Good to know the people in the know are keeping up with us plebs, lambs due for the slaughter.  

Everyone is banging on about masks, what about eye protection? Tear ducts lead to the nose and therefore the throat, therefore the respiratory tract. Just saying.......What do I know?, I hit stuff with hammers for a living

But in all fairness it didn't take a genius to figure it out. We know doctors wear more protection because they are exposed to a much greater number of particles (viral load) and we've been told that the viral load does matter, because beyond a certain point, the little defenses the body can muster are overwhelmed by the virus.

But we are stuck in the stupidest timeline ever, where people are the absolute worst patients a doctor would want. Maybe we are all already in hell, and this is like the movie Groundhog Day. Any hope for a controlled low-density of cases is long gone and we are suffering through exactly what doctors were trying to prevent, with a risk of not being able to control it at all - that's when you need to be equipped exactly the way a doctor is in a hospital setting. Dr. Fauci is just trying to stay ahead of the idiots.