Economy Ventilator

What exactly are you asking? Prototype Development?

Hi The people that I assisted with this design had spent two years and some two million NZ dollars ( yes 2M!) on it sitting on a gravy train. A friend was the individual putting up the money and asked me to look into the situation. I worked on it on a Sunday and supplied it to them on Monday morning. The CEO for its development went home that afternoon and by coincidence I had purchased a renter across the road from his house, he said hello across the street went inside the gate and dropped dead. I do not know what happened to the design. Dark hours call for effective operational parameters, forget the aesthetics!

An article in yesterdays Boston Globe, a doctor from one of Boston's hospitals was making a plea for just what you are proposing: simple, inexpensive, easy to service, and ugly.

Thanks for the link. Took a bit to get to the article as I don't subscribe to that paper, but probably fits the bill.

I'll set a reply post to the thread and you guys can do with it what you will.

Vets are being asked to offer up their ventilators as backup for hospitals.

I wonder if other countries have done this too ?

https://www.abc.net.au/news/2020-03-25/vet-ventilators-may-be-used-to-treat-coronavirus-patients/12086662

I did some R & D on this too for some brain food , after realising that some components i would use to build one were manufactured for RESMED to be used on their sleep apnoea machines , I then took a look at that company and found reference on their website that they have a few thousand staff working to supply their equipment modified for use as ventilators.

I am not going to dissuade you from working on yours though.

You're in Oz- is there any demand for it there (yet??)?

I know some people/ relatives etc. down there that are in manufacturing fields and have a bit of capability if there is.

Hospitals in Australia can’t get enough of anything right now.

they are expecting to be swamped in the next 7 - 10 Days by around 500 % more patients than what they have bed capacity for.

85 % or more of Doctors and Nurses are running around with paper Surgical masks when they should be wearing hazmat suits.

They need better PPE , containment tents , CPAP and NIV hoods and oh... a vaccine.

note the bottom left pic is not a medical mask , it’s a ScapeHood which only gives 30 - 60 minutes runtime for emergency egress.

Awesome , Hope you get a solution for that.

I have been researching medical grade powered filtration masks for medicos to use when treating CovId-19. ( The ones with a full hood covering head and shoulders like hazmat suits )

Despite the billion dollar nature of the biggest companies who manufacture these things , none of them have manufactured devices that filter the dirty air outlet from these masks.

The intake air fed to the mask is filtered but the outlet air is not.

In China they estimated 20 % of deaths were healthcare workers who would have been carrying the virus and breathing out “dirty air” in their work environment.

Hospital grade filtered air systems therefore need to be upgraded to also filter the outlet air to account for the probability that the medico could be a spreader who continues working until they drop or are quarantined in a hospital bed.

I contacted the worlds biggest manufacturer yesterday who responded with ... “I think you have made a valid point....but we don’t have a product to provide that function”

will your ventilator have filtered outlet ?

The ideal case is having the patient in a Posey tent ( isolation tent fitted on the bed ) and they do have medical oxygen inlet and some have filtered air outlet.

I nearly missed that point , mind boggling now i think about it with CoronaVirus treatment clinics but also in our BioMedLabs.

"The intake air fed to the mask is filtered but the outlet air is not.

In China they estimated 20 % of deaths were healthcare workers who would have been carrying the virus and breathing out “dirty air” in their work environment.

Hospital grade filtered air systems therefore need to be upgraded to also filter the outlet air to account for the probability that the medico could be a spreader who continues working until they drop or are quarantined in a hospital bed."

The idea.

We've all seen the Emergency Department or ambulance using a "bag" to manually ventilate patients. The proposal merely replaces the person "squashing" the bag, minute after minute, hour after hour, day after day if necessary.

Simply, the motor (I'm suggesting a windscreen wiper motor unless something better is available) is used to drive a shaft with a cam that causes an upper platen to move up and down. Essentially fixed stroke and relatively fixed frequency. The volume is adjusted and set by the spacers underneath the bottom platen, adjusted to each patient as suitable.

The ventilation bag is placed in the gap.

Yes there are limitations and there are options for other features, but as a basic starting point this could be useful.

The main thing is that NOTHING of this device forms part of the airway to the patient as it uses devices already available and in use.

Yes, it is clunky and will be ugly, but could be constructed with a wooden or metal frame depending on available materials and thus could be built on site anywhere around the world.

Copyright to me, but available to anyone that believes it could assist in their situation.

Other notes:

• Probably not "Oxygen rich" safe, but wiper motors are highly reliable.
• The device will provide fixed volume each stroke. There needs to be some pressure relief in the delivery tube to the patient in case the patient has an airway obstruction to avoid over-inflation of the lungs and the damage that could cause.
• The cam needs to have around 50% of cycle with bag at fully open condition to allow the patient to exhale.
• The cam should have a quick, but quiet return from fully compressed to "home", otherwise it will be noisy and self destruct.
• The rubbing point of the cam will need care/attention/observation. While the actual force will be minor, the available materials might not be ideal.
• Windscreen wiper motors are available worldwide, already geared to low cycle speeds and easily handled.
• Refinement could be achieved by using an intermittent wiper control to provide simple cycle per minute adjustment. That can come later.
• The surfaces "squashing" the bag might need "soft" covering to prolong the bag life.
• There is NO FEEDBACK to the machine. It is DUMB and will just keep on cycling.
• There are some obvious OHS pinch points when operating. Sort them out or put guards on it.

Well, this is the perfect place to kick this around and come up with something quick and not so dirty that can be done in a day!!

My two cents - change the cam to a fixed arm linkage (rotating arm and connecting rod) with an adjustable length on the rotating arm to change the volume per stroke. Very easily done if you use something like Unistrut for the arm and just set the stroke with a thumscrew or wingnut attachment to the connecting rod. That way it also retracts the platen; I assume you need to do that with springs otherwise? I know nothing about ventilators.

Pressure relief - what is allowable? Put a tee on the output with a balloon tie wrapped over the diversion port!

Hi, I am totaly new to this, however have designed a ventilator previously which was not dependant on electrical power and was self regulating according to the lung capacity of the patient. The use was for emergency situations in mountain rescue etc.

The novel component was a hexagonal piece of spring steel fixed at one end at right angles to its length while the main effective spring length was adjusted via a thread based clamp operted via a longitudinal slot running parallell with the main spring length so as to alter the functional spring length. The rightangled opposing end was attached to the bellows which were pleated tyvek.

Sounds excellent! I am interested, so please keep me posted. We are in the lull before the perfect storm. My info is andrew@macgregor.co.za, Cape Town South Africa.

After reading some of the posts, the assumtion that a cam should be used overlooks the fact that second hand windscreen wiper motors come with a crank on the output shaft that gives about five inches of throw, this shaft usually has a ball joint and pushrod attached to transfer the movement into the pantograph mechanism, surely it could be converted to an adjustable length shaft to alter the compression of a bellows to adjust the volume per throw, and the amount of scrap motors around must be enormous especially in third world countries.

Just an observation, guys; I've always been a big fan of junk windscreen wiper motors they have so much power and go forever!

Stay safe everyone.

They would need adjustment in stroke to compensate for different lung capacities.

A high tech machine would use sensors to adjust flow rate and pressure because a human lung doesn’t breathe evenly all through the in breath and out breath cycle; there is a dwell or pause at the beginning and end of each. However, an eccentric cam like OP proposed may do exactly that, provided the volume was controlled, plus incorporate an overpressure control and relief valve.

CPAP pressure might be from 6 - 15 cm/H2O.

High tech proper machines might also sense heart rate and slow down the ventilation cycles to correspond with heart rate or vice versa.

I heard it's easy to convert anesthesia machines to ventilators...could possibly be sourced from veterinary stock....

Though these are pneumatically driven..

You need a 12vdc power source for these though...

Maybe some good ideas here using CPAP equipment...

There should also be some moisturizing component to prevent drying out the mucous membranes, some periodic mist injection perhaps...

More to chew on.

The shampoo bottle saving babies from pneumonia

I absolutely applaud what you are attempting to do and would love to see you succeed. Unfortunately, in the US, it would probably need FDA Approval.

There are hospitals that are even taking goods that are past their expiry date out of desperation because that’s all they can get.

Hello and thanks for your support.

The whole idea of this is that it introduces nothing new to the airway or passages to the patient. It merely provides a low tech means to activate a breathing bag for the patient.

Those in the industry would already realise that they still need humidification (so the patient's lungs don't dry out) and pressure relief (so the patient's lungs don't get damaged) and so on. Those features should be possible from other local and already FDA approved items.

I can understand that the regulatory body MUST be involved. I would anticipate they would mandate the need for an approved pressure limiting relief to be in the line between this and the patient. I would anticipate they would regulate whether it could be used in Oxygen enhanced situations.

If this is suitable, then the problem that I anticipate is the TIME that it would take them to make the decision.

I would also EXPECT that if they did enable the use of this or similar that it would be as "concession" and rescinded immediately the situation returns to some resemblance of order.

I compare this more to the ground staff during the Apollo 13 mission developing a means to jury rig the O2 equipment, as the alternative was not acceptable. What is available NOW? Resources, materials, time, technical capabilities.

The simplicity means that it could be manufactured at almost any hospital site, eliminating the logistics issue of centralised manufacture.

When considering design elements be mindful of flameproof ratings for the motor , enclosure and speed controller circuits.

PPV , NIV , CPAP ventilators could be supplying oxygen at 21 - 60 percent.

we dont want any explosions , can someone validate if Oxygen has its UEL at 22 % or so ?

James Dyson came up with a new ventilator design in 10 days

https://edition.cnn.com/2020/03/26/tech/dyson-ventilators-coronavirus/index.html

Uncle B

Is always ready to hat his throw up into the ring.

The amazing phasatron...

awesome and amazing

Wonderful!!!!!!

So much better than my original concept. How do we get that produced and "approved" outside the USA? There are some places ahead of you on the infection "curve" that are already desperate.

Found this....

https://de.dotmed.com/listing/other/percussionaire/a50605/phasitron-breathing-circuit-kit/2279036

Interesting that there’s an expiration date on it...

A positive, but CORVID-19, people are getting a good basic understanding of not only the virus itself, but the equipment used to treat it.

brilliantly simple so long as they can still connect a humidifier and temperature compensation to the incoming air.

adding oxygen to the airflow would be easy.

When the world mobilizes, good things happen fast.

Dyson designs ventilator in 10 days, making 15,000 amid pandemic

On the weekend, I saw a UK device that I would describe as "air over air" where the compression of the item like a "football bladder" was done inside an enclosed box using the hospital air line.

Specifically commented about the absence of mechanical gears and such, but didn't comment on the pneumatic solenoids.

From memory it was a collaborative university group that expected to have plans available Monday 30/3 as open source information.

I believe that my proposal and this UK option both face the challenge of an Oxygen rich environment, even using low voltage devices.

I am glad to see that the world is progressing on this.

I love reading everyones post on this topic there are so many possibilities.

I feel that what we need to be thinking about is retasking parts that already exist in the manufacturing world. Parts that can hold low pressure or be sealed against the environment to allow the pateint air to remain sterile or at least uncontaminated by foriegn substances.

It's all very well to design something new but the lag between concept and delivery could be long if special to purpose parts are required in large quantities, how long will a mould tool take to create and prove then you only have one of them so only one moulder can make them, etc.

3D printing can help but its incredily slow and not ideal to mass production.

Off the shelf parts should be able to meet the requirements, it doesn't have to look like an F1 car or last forever, just work until it wears out, what it looks like is un-important right now. As long as its safe and serviceable, thats it.