Thanks! With "social distancing" I'm pretty sure my filter bag wont take a direct hit like that.
Yeah, I just went shopping on ebay for an industrial grade mask and filters. I can tell all the scammers are coming on line to take advantage of the situation - it took a couple hours to decide on a valid USA seller for a mask and cartridges.
If you search ebay for "DC 12V 12L/min Diaphragm Pump" a few examples of the pump I have (the round white one) will come up.
If others are interested, here's what I purchased; You can easily search -
North N7500-2 Respirator Cartridge 2pk (NEW) (5D7)
7700 SERIES SILICONE HALF MASK RESPIRATOR LARGE 770030L - 1 Each
According to Amazon reviews, the 7700 series is really good.
For anyone still following, I've verified the 1.5A motor current for the 12L/min pump. That should give an operating time of maybe 1.5 hours to 2.8, depending on the 18650 cell capacity.
I've been looking at other purchasable equipment to improve the apparatus. I bought 4 of the following; Allegro Hood Assembly, Tyvek(R) 9910-10 | Zoro.com for $100. Stepping beyond that which I happen to have in the house...
The hood looks like it's gonna do it. For that price, I didnt get the hose connection, so that's going to be the first challenge in order to use them.
I've been thinking of filters I could buy. Looking strongly at Okaysou AirSlim6C Air Purifier True HEPA Active Carbon Replacement Filter 1 Pack | eBay
as it's also HEPA rated and as a room purifier filter, looks like it'll do the trick as well as the vacuum bags.
I've also been wondering if the 12L/min diaphram pump is my best choice, or if I should go with a squirrel cage blower. There's a 20L/min piston pump on ebay, with the same brushed DC motor. There's also a type of squirrel cage fan I used to work with; Delta 97mm x 33mm 12V 2.94A Extreme High Speed Centrifugal Blower Fan 3-Pin | eBay though it is a killer fan compared to 12L/M.
It would be interesting to combine filter and fan, use a PWM motor speed control to lower the voltage (hence RPM) and see how it inflates that tyvek hood. Maybe a tornado in there...there for sure would be at full 12V power. I want the reliability of such a brushless, ball bearing fan; there seems to be other, lesser performing units available.
These are not particularly expensive component investments for something you can use to protect yourself when doing business in closed quarters that involves other people and takes time. I think filtering your own breathing air, on the spot and in real time is a good way to go - to lessen the chance of accumulating a viral load from the airborne aerosol vectors.
The hoods also prevent accidental face touching - and frankly I'd rather have some standing near me sneeze in one of these hoods than out into a room full of people. I think it would effectively block the projection velocity allowing people to clear the area in time.
I've been looking at other purchasable equipment to improve the apparatus. I bought 4 of the following; Allegro Hood Assembly, Tyvek(R) 9910-10 | Zoro.com for $100. Stepping beyond that which I happen to have in the house...
The hood looks like it's gonna do it. For that price, I didnt get the hose connection, so that's going to be the first challenge in order to use them.
I've been thinking of filters I could buy. Looking strongly at Okaysou AirSlim6C Air Purifier True HEPA Active Carbon Replacement Filter 1 Pack | eBay
as it's also HEPA rated and as a room purifier filter, looks like it'll do the trick as well as the vacuum bags.
I've also been wondering if the 12L/min diaphram pump is my best choice, or if I should go with a squirrel cage blower. There's a 20L/min piston pump on ebay, with the same brushed DC motor. There's also a type of squirrel cage fan I used to work with; Delta 97mm x 33mm 12V 2.94A Extreme High Speed Centrifugal Blower Fan 3-Pin | eBay though it is a killer fan compared to 12L/M.
It would be interesting to combine filter and fan, use a PWM motor speed control to lower the voltage (hence RPM) and see how it inflates that tyvek hood. Maybe a tornado in there...there for sure would be at full 12V power. I want the reliability of such a brushless, ball bearing fan; there seems to be other, lesser performing units available.
These are not particularly expensive component investments for something you can use to protect yourself when doing business in closed quarters that involves other people and takes time. I think filtering your own breathing air, on the spot and in real time is a good way to go - to lessen the chance of accumulating a viral load from the airborne aerosol vectors.
The hoods also prevent accidental face touching - and frankly I'd rather have some standing near me sneeze in one of these hoods than out into a room full of people. I think it would effectively block the projection velocity allowing people to clear the area in time.
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I work for Verizon as a field tech, doing fios fiber optic service install and repair. We are still working in homes and businesses, the company is trying to limit installs somewhat, data, and only one tv box, but, I'm in the house, I feel like if I'm in for a penny I'm in for a pound. Short of a full hazmat suit, I doubt a mask will do much of anything to keep me safe. I'm 49, relatively healthy, I do practice some regular abuse of myself smoking and drinking, but I work for a utility, and consider myself lucky I'm still collecting a pay check. I've been with Vz for 20 years, and regularly work in filthy houses, we cover some less than good areas. I have seen and smelled so much filth and weird s**t, that NOTHING shocks me now, we've all joked about our supercharged immune systems from exposure to so much of this stuff! Hopefully my luck will hold out (I've always been lucky that way, gotten through some crazy scrapes that could have and probably should have killed me. I've gotten into a lot of trouble! My old friends remind me of this on occasion.). But if you can stay home, certainly do so, and don't stand so close to me dammit!
If you can I'd certainly try to pick up a respirator, one of those with the tighter fitting soft mask that covers your nose and mouth - has the two filter cartridges on either side - like this guy is wearing.
It's unclear to me if you can talk to a customer wearing one of these, without compromising the seal about the mouth and nose. Maybe smear a little vaseline to help ensure a airtight fit to your face.
I've read the "novel" protein spikes on this virus make it more infectious once it enters the nose / throat. So minimizing the "viral load" you may pick up is paramount, so, minimize time spent in an enclosed space (where other people are), keep your distance - and use a respirator of some kind.
I'd think a place like the big V would have them in the shop. Demand that you get one to do your work! Dig through shop supplies until you find one.
Ordinary face masks protect others from projected aerosols coming out the wearer, for the apparently very popular situation where someone has it but honestly doesnt know.
Only with a tight seal to the face (which I assume is hard to perfect when initially putting into place - nevermind maintaining throughout a work day) will offer some protection against airborne aerosols. I know "skin glue" exists for attaching medical apparatus. Havent read yet of someone using that stuff to seal a cloth/paper facemask.
Good luck to you as you work through the forthcoming days.
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I looked up some flow rates for professional "PAPR" units and it was very difficult to suss out - they dont just give you the flow value their air pump puts out, like a speaker spec would reveal the db/w efficiency.
Seems they want you to replace filters when flow drops between 4-6 CFM, which translates to about 140 L/min, so my 12L/min value is off by a factor of 10! You can buy these things on ebay from several listings, such as MSA OPTIMAIR 6A BLOWER UNIT FOR PAPR SYSTEM WITH BATTERY | eBay
Seems they want you to replace filters when flow drops between 4-6 CFM, which translates to about 140 L/min, so my 12L/min value is off by a factor of 10! You can buy these things on ebay from several listings, such as MSA OPTIMAIR 6A BLOWER UNIT FOR PAPR SYSTEM WITH BATTERY | eBay
Since my 12L flow rate is sadly low (have one datapoint saying adequate for sedentary) I need a better pump. All I happen to have on hand is this coleman 12V inflator, which really takes off on 12V, pulling better than 7A. Definitely will need a PWM controller to reduce power and therefore, current for long term steady state flow usage. I bought two unbranded Chinese versions for <$20 on ebay.
I purchased a couple of Delta BFB1012M-A, which is also a centrifugal cage fan, whos spec says it can deliver the 100+ L/min at 0.8" pressure. As I have no idea what the pressure will be to drive air into a loosely vented under jacket hood, so these fans are a <$20 gamble. They take 0.85A current at 12V
Bought a pair of the Okaysou AirSlim6C filters, to use with the above, also <$20.
Finally, I'd like to call attention to BULLARD POWERED AIR-PURIFYING RESPIRATOR PAPR EVA BLOWER UNIT | eBay which is a professional PAPR flow pump. The seller has over 100 of these at a very reasonable price. Whether they can be adapted to just any battery (noticed battery connector has 4 terminals, so maybe refuses to energize without OEM battery pack (not included), nor does it come with a filter) or filter remains to be seen. I notice it does use a similar centrifugal type fan to the units I purchased, though who know what the model / specs are w/o a teardown. Seems quite a bargain, as a whole system is in the kilobuck range.
I'm hoping something effective and actually nice to use can be assembled for <$100 per person -
I purchased a couple of Delta BFB1012M-A, which is also a centrifugal cage fan, whos spec says it can deliver the 100+ L/min at 0.8" pressure. As I have no idea what the pressure will be to drive air into a loosely vented under jacket hood, so these fans are a <$20 gamble. They take 0.85A current at 12V
Bought a pair of the Okaysou AirSlim6C filters, to use with the above, also <$20.
Finally, I'd like to call attention to BULLARD POWERED AIR-PURIFYING RESPIRATOR PAPR EVA BLOWER UNIT | eBay which is a professional PAPR flow pump. The seller has over 100 of these at a very reasonable price. Whether they can be adapted to just any battery (noticed battery connector has 4 terminals, so maybe refuses to energize without OEM battery pack (not included), nor does it come with a filter) or filter remains to be seen. I notice it does use a similar centrifugal type fan to the units I purchased, though who know what the model / specs are w/o a teardown. Seems quite a bargain, as a whole system is in the kilobuck range.
I'm hoping something effective and actually nice to use can be assembled for <$100 per person -
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You do you, but I'm ordering from Amazon or Whole Foods delivery before I walk into a supermarket looking like a space cadet gone wrong.
Or a Polski Elephant Man?
Hey, I got some professional white tyvek PAPR hoods with nice, smooth clear viewing window on the way. 10X the price of round bottom 4 mil poly pail liners, which would be just a bit harder to see through, but could do in a pinch.
The coleman fun-tube inflation pump is actually a contender, as it is something people just might have kicking around. When used with the ebay PWM controller 12V-40V 10A Pulse Width Modulation PWM DC Motor Speed Control Switch Controller | eBay I can get better than the diaphram pump flow at < 1A current from a 12V supply.
I'll have to setup an RC filter at the motor terminals to see what the equivalent DC voltage to run it this slow - maybe it's a value like "3".
It's very, very noisy, even at low RPMs. I assume the thin, ringy, plastic impeller cant be removed from the motor shaft, to perhaps coat the backside with some damping material. 4 screws hold the impeller body clamshell together and I did put 4 rubber washers at the butt ends of the screw receiving plastic pillars which did quiet it down some. Wish I had some of that "black hole" speaker interior cabinet resonance reducing paint on hand...
Hopefully next trip out will be with this air pump and the real hood. I ordered a set of Samsung 18650 batteries 4 SAMSUNG 26J M 18650 ICR 5200mA DISCHARGE 3.7V RECHARGEABLE BATTERY 717356043703 | eBay for <$20.
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