Austere Medical: Pressure Canner Autoclave

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This blog post is not in any way to be considered as instructions or advise.  It is so others can see how I do it.  Individuals performing any of the following do so at their own risk and assume all responsibility and liability for their actions.

eye of the storm image from outer space

Photo by Pixabay on Pexels.com

In South Florida we have the potential to be without electrical power for long periods of time after a hurricane.  One hurricane left us without power for 3 weeks.  That potential left us asking, how would we sterilize medical instruments without a commercial autoclave in austere conditions?

With that in mind I set out to see if I could purchase or construct an autoclave that did not require electrical power to operate for under $200.00 dollars.  At first I found electric autoclaves that were priced $700.00 dollars and up.  Those were out of our budget and electric which wouldn’t be very useful for the situations we envision using an autoclave in.  There were non-electric stove top units for $300.00 up to over $600.00 dollars.

The $300.00 dollar unit was only 9.5 quarts much too small for large instruments or packs.  300 seemed like too much for such a small unit.  I was somewhat disappointed that there seemed to be few options but the commercially made out of budget autoclaves.

Not satisfied with that I started searching for possible ways to construct a homemade autoclave out of readily available materials.  That search led me to this PDF document titled “Use of pressure cookers for sterilization of clinical instruments” found here Link to original location for experiment inspiration.  The paper refers to a study conducted by the Dental School of the University of Texas Health Science Center at San Antonio in 1997 which evaluated pressure cookers for their autoclave capabilities.

After reading that paper I decided to try to find the 22 quart pressure cooker/canner mentioned in the paper.  I was able to locate a Presto 22 quart model 0178003 on ebay for $59.99.  It was in excellent condition.  All of the gaskets were changed including the over pressure plug for safety.  It also seemed to be good idea since gaskets were mentioned in the document as a potential problem point.

GAUGE

All-American gauge left, Presto gauge right, brass pipe fittings.

Also added was an All-American autoclave pressure gauge.  Since there isn’t anyone local to test our pressure canner it seemed like a good idea to add a pressure gauge that was made to be used with an autoclave.  I also wanted to keep the original gauge and see how they compared during testing.  To do this 1/8″ brass pipe fittings were added so that both gauges could be monitored during a sterilization cycle.

legs

3″ stainless steel screws for legs.

After installing the gauges, gaskets and seals I installed 5 stainless screws on the cooking rack that separates canning jars from the bottom of the canner.  I left the rest of the rack untouched.  During testing all of the packs came out wet.  The rack had a few large holes leaving a lot of surface space for water to accumulate.  To give more drainage the entire surface of the rack was perforated by drilling as many holes as I could without compromising the integrity of the rack.

After several tries the packs were still wet where the water wouldn’t drain off.  I thought it might be there was still too much surface and surface tension to release the standing water.  Also during those test I realized I needed something to prop the pouches and packs against so there would be room for the steam to pass and give the ability to add more instruments.

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Stainless grill grate.

Another thing considered was that maybe the aluminum was cooling before the water had a chance to evaporate.  I started searching online for a stainless steel cooling rack or grill grate.  I found a 10 1/2″ stainless round grill grate on ebay.  Also needed was something to separate the packs and pouches.  I ordered a length of stainless steel wire online, wrapped it around something which I can’t remember to coil the wire to the shape I wanted.  That piece of wire would push into the grill grate in several ways to accommodate the various pack/pouches.

RACK:WIRE

Grill grate with wire coil.

Also during that phase of testing I noticed that once the cooking/drain rack was loaded with packs there was no way to remove them without touching them before they had a chance to cool down.  I had a short piece of aluminum flat stock laying around so that was bent into a handle shape then attached to the cooking rack.

HANDLE

Cooking rack with attached handle.

The information in the document mentioned the success difference between the 15 psi and 20 psi pressures.  It seemed to me that the preferred pressure would be 20 psi since the document on page 6 stated “No positive cultures were evident in any ampules processed at the increased saturated steam pressure for 5, 10, 15 and 20 minutes in all vessels.”

RACK IN AUTOCLAVE

Cooking rack, grill grate and wire coil

3 piece

3 piece pressure regulator

A 3 piece pressure regulator was purchased to use for parts to add to the regulator that came with the pressure canner.  To achieve the 120 grams as the document mentioned one of the weights from the 3 piece regulator was added with 2 washers.  The pick up knob was modified to accommodate the washers so that they would stay centered on the regulator.

After multiple test to assure dry packs and a consistent pressure of 21 psi it was time to see if the modified canner could function as a successful autoclave.  Mail in spore test containing Geobacillus stearothermophilus from Mesa Labs were ordered to determine if packs had reached sterilizing conditions.

Instruments were packed in commercial pouches, muslin and CSR wraps to determine if they would interfere with the process.  Packs were packaged tightly to make it as difficult as possible for steam to penetrate the pack to the place where the test were located.  I was trying to get the process to fail.  It never did.

SPORE TEST

Spore test results

Test results for the thickest pack passed 2 times.  The other packs and pouches passed as well.  That’s still no guarantee that the packs are sterile.  Anyone who processes packs knows that the only place we have any certainty of sterilization was where the test strip was located everything else is assumed to be sterile.  I feel confident that sterilization conditions were sufficient throughout the canner so much so I’ve added it to our aid station equipment.

Since there were no specific instructions mentioned in the document I used the instructions for the All American autoclaves.  After multiple test conducted I noticed that instead of the 15 cups recommended in the document I was able to use as little as 11 cups but added 12 cups to ensure the cycle wouldn’t dry out.

The steps I followed, also our standard operating procedures(SOP), are the following:

  • After the canner is loaded with the 12 cups distilled water and the packs the heat source is set to high to bring the water to a rolling boil.
  • Once boiling and there is a steady stream of steam venting from the vent pipe a timer is set for 7 minutes
  • After the 7 minutes the pressure regulator was placed on the vent pipe.  The pressure is allowed to reach the desired 21 psi.
  • When the pressure reaches 21 psi the pressure regulator is removed to allow pressure and steam to escape for 4 minutes in an attempt to evacuate all ambient air which may not sterilize if trapped in the canner.
  • After the 4 minute venting cycle is complete the pressure regulator is placed back onto the vent pipe.
  • When the pressure on both regulators reaches 21 psi the heat source is turned down to maintain pressure throughout the sterilization cycle.
  • After the heat source is turned down a timer is set for 5 minutes.  During this time the pressure is monitored to ensure it does not go over 21 psi.
  • Once the pressure is assured a timer is set for 35 minutes to ensure that all parts of thick packs are sterilized.
  • After the sterilization cycle the packs are removed and the canner is emptied of water.
  • The packs a placed back into the canner on the heat source set to low to start a dry cycle of 35 minutes.
  • Once the 35 minutes have passed the packs are removed and allowed to dry for 6-8 hours.
  • After the packs cool and vent any residual moisture they are placed into plastic pouches and vacuum sealed to preserve the sterility.

SOP’s also include when using a new heat source running at least 3 test to ensure consistent pressure throughout the cycle.  We use indicator tape as well as test strips to indicate a cycle is successful.  Project cost for the canner, replacement parts and parts for autoclave use was $170.13.

Dangers are explosion if safety features are modified and severe steam burns if a heat protective glove is not used when placing or removing the pressure regulator weight.  This type of autoclave must never be left unattended and the pressure must be constantly monitored for consistency and safety.

We have a working autoclave for austere conditions!  Now we can sterilize instruments wherever we have a consistent heat source whether it’s in our back yard after a hurricane or in a remote location far away from help.  -13

Link to additional information about pressure cooker autoclaves

Check out this 20 minute video about our pressure canner autoclave.

 

 

 

 

Worm bin notes: Update 25 Worms love avocados!

Bins 2 & 3, Update 25.  When opening both bins I noticed the moisture was higher under the cardboard covering.  The spiders seem to have been wiped out by the lizard visits.  I didn’t see any in either bin.  The small white dot insects are still in both bins in abundance seems like the moisture helped.  I’d would like to try to capture a few one day and look at them under the microscope.  They’re so small they look like tiny moving white dots in the bins.

 

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Bin 2 Oct. 29th

B2 NOV 16

Bin 2 Nov. 16th

The other unidentified insects are also there but no as many as before.  The heat may have been too much for them.  Bin temperatures were 72.1° F. – 72.5­­° F.  The ambient temperature was 72° F with 56% humidity.  I watered both bins to get the moisture up at the surface.  The hand sprayer sprung a leak because I left it under pressure and in the sun.  Looks like its time for a new one.  I used the 1 gallon garden sprayer as a substitute and may keep using that instead of the hand sprayer.  I’ll use it next time and see how it goes.

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Bin 3 Oct. 29th

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Bin 3 Nov. 16th

One thing is for sure the worms really like the avocados.  As long as they are not rotted or dried out they devour them.  I still think their favorite is the mangoes and fresh greens.  It seemed like the cardboard cover is thinning out I’ll add more next time I check the bins.  -13

Latest video below.

 

Worm bin notes: Update 24, All is well!

Bins 2 & 3, Update 24.  All is well in the bins.  Ambient temperature of 86°F, 70% humidity, bin temperature 82.5°F.  The bin temp is a little higher than I’d like but there is no where else to keep them.  No foul odors.  Nothing out of the ordinary.  There were few or no spiders.  That makes me think there has been a lizard or two dropping by for a few snacks.

I’ve noticed but keep forgetting to mention, the other two insects usually seen in abundance in the bins are hardly visible.  I think the continuous air flow and drying of the surface has had an effect on them.  Next time I check the bins I’ll add more moisture and possibly add more cardboard in an effort to keep the moisture level higher.  Maybe the other insects will flourish again.

Since there isn’t much potato on the potato skins I’ve started adding them back into the bins to simulate leaf litter.  I’m also hoping the addition of moisture will keep them from drying out creating a more natural type environment for the worms.  I’d like to see more activity at the surface again.  Stopped using the fan since there has been small patches of moisture and discoloration on the floor next to it.  It’s “winter” here in Florida so the ambient temps should be more mild.  We’ll see! -13

Dash Cam: Camera tampered with during vehicle maintenance.

toyota

On 18 Octobrer 2019 our 4Runner was taken to Toyota Hollywood for maintenance. Before the vehicle left for the day I did what I do every day or two. Change out the SD card, clean the lens and check the position of the camera view. Everything was like it was supposed to be with a good camera view. When the 4Runner returned I started to change the SD card and noticed the camera was pointing in an upward direction.

before

Before camera is moved.

That’s odd I thought because for the camera to be moved into that position it would have to be forced that way.  The mechanism that controls the vertical view of the camera has a knob that is tightened by hand. It also has indexing teeth so that the camera will stay in position once adjusted.

CT

After camera is moved.

That then made me suspicious since the vehicle had maintenance that day.  I loaded the footage on my computer.  I was not surprised to see footage of the camera being manipulated. Someone started to move the 4Runner then slowed down as the camera was moved. The slow motion video demonstrates the indexing I was referring to.  The clicks are visible in the footage. Adjusting the rear view mirror does not interfere with the camera.

demo

The employee cannot claim it was bumped by a hand. I included a demonstration of how difficult it is to move the camera in the video I put together about what happened.  So why would an employee of Toyota Hollywood be manipulating the camera without permission?  Does the employee have something to hide.  Does Toyota Hollywood?  The camera is not a Toyota part.  We put the camera in for our protection. They don’t have the authority to touch that camera or any other personal item.  This makes me very suspicious of what is going on in their garage.

There is a guy that keeps showing up in the footage who is the one performing the maintenance.  I’m not accusing the guy but do wonder if it was he who moved that camera.  Whoever it was I want to make sure that person never has access to any of our vehicles again.  The only person that could have moved the camera was the one who was driving it at the time.

I made a video record of the event that includes all the recordings from the time the 4Runner arrived at Toyota Hollywood to the time the person performing the work parked it outside.  Nearly all of the footage playback speeds have been changed to move though the timeline faster.  I included footage of me manipulating the camera angle and some slow motion to see movement detail.

For now all we can to is let the management know what happened so the issue can be addressed.  I’m posting this video so the management can see the actions that bring us concern.  As well as letting people know what took place there. We are shocked and disappointed this happened.

We want to know who did it so we can assure that person never accesses our vehicles again.  That camera is set to turn off after the engine stops. In the future when maintenance is performed the camera will be set to continuously record once it arrives at the garage.  Video is below. -13

 

Worm bin notes: Update 23 Getting back to normal

Bins 2 & 3, Update 23.  Looks like the bins are getting back to normal as well as the local temperatures.  The heat wave has let up and the worms are becoming more active.  Bin 2 temp was 81.8ºF, bin 3 was 82.2ºF with an ambient temperature of 86ºF, 69% humidity.

No foul odors to report in either bin.  Both bins showed signs of the surface drying out.  To remedy this I added more cardboard and made sure to push it down closer to the surface.  This should help trap the moisture in.  I’m sure the constant shop fan blowing on the bins the during the heat wave has contributed to the drying.  Next time I check the bins I may add some water to keep it moist enough to keep the worms happy.

There was a gecko in bin 3 as shown in the video.  It’s easy to see in both bins how few spiders there are in there.  Don’t remember seeing any in bin 3.

These updates have been getting shorter in length since the bins are getting back to normal and I’m not trying much new with them.  I’ve also decided to stop adding photographs to the updates unless I want to show something.  I’ve been so busy with other projects I don’t have the patients or time required using an Apple computer and phone.  Too many steps to do something that I could do much faster on a PC.

If I want to transfer photos and video from my iPhone onto my PC all I do is access the phone, highlight the items I want on the PC and drag them to the folder I want them in.

With Apple I have to open iMovie to get the photos and video to make the video.  If I want to use the photos on this blog I have to open photos, transfer them to photos, then transfer them to another folder on my desktop.  It’s become too much.  Apple is not user friendly they want too much control over my property.  Not cool.

I hope those few that do follow this part of my blog understand. It’s also why I make the videos, they have the same details.  This blog is a place for me to write notes of the checkup and things I may have left out of the videos, and for future reference should YouTube disappear or the ban me.  At least I’ll have some record.  New video is below check it out.  -13

 

Worm bin notes: Update 22 Dorian cools temperatures, worms feast

Bins 2 & 3, Update 22.  This is going to be a short update.  Last week south Florida was preparing for hurricane Dorian.  That created lots of clouds and rain.  The lower temperatures brought the worms back to full speed and they devoured waste added from the last feeding.  I had made preparations to bring the worms indoors if the hurricane was going to pass thru here but we were fortunate that it did not move into this area.

gecko

Gecko hidden in bin 3 handhold.

For update 22 the temperature in bin 2 was 83.3ºF, bin 3 was 81.8ºF with an ambient temperature of 85ºF, 70% humidity.  There were no noticeable odors in either bin.  We did have a couple of geckos in bin 3 but they fled the disruption.  Everything is in the video.  My favorite part of the updates are the before and after images that demonstrate how much waste those worms can consume when conditions are to their liking.  Video is below.  -13

Dash Cam: More mayhem in south Florida

107-110 are posted on the South Florida Driving 101 YouTube channel.  I still find it amazing how much footage is generated by our dash cameras.  If you’re ready for more jets, zombies, cut-offs, crazy exits and merges, and stupid we have it on video.  Over a 110 videos so far with the specials.  I’ve also recently found multiple dashcam channels on YouTube in Florida.  They’re listed in our Featured Channels links on our front page go check them out and subscribe. Enjoy the crazy drivers -13

 

 

 

 

Defensor Fortis LCS PALS Filler Panel

IMG_5474

Defensor Fortis – Load Carrying System

Once again another DF-LCS (Defensor Fortis Load Carrying System) modification.  This time it’s for the elastic that connects the rear section to the two front sections.  After using the DF-LCS I was unhappy with the unused space created by the elastic connection and wanted a solution.  I had a surplus fighting load carrier (FLC) on hand when it dawned on me to break it down into individual components and reuse the parts to fill the space.

elastic

Elastic connector between front and rear DF-LCS sections.

The PALS (pouch attachment ladder system) panels on the FLC would be perfect with little modification necessary.  Once they were removed from the rest of the assembly it would be easy to cut the parts to size, sew on the recycled edge binding, then sew the free ends together.  This would allow them to slip over the elastic connector then be laced to the front and rear section of PALS webbing with military spec paracord.

IMG_5495

PALS filler panel over elastic connector, laced onto front and rear sections.

The idea works well for the ALICE M-16 pouches I converted to MOLLE.  So far those have performed as expected when the ALICE magazine pouches are fully loaded with gear.  I did have to tighten the lace up to eliminate the slight sagging issue.

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Front view ALICE magazine pouch attached to PALS panel.

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Rear view of ALICE magazine pouch and PALS panel on a DF-LCS.

I don’t have a lot of detail here because it’s in the video.  The video moves from FLC disassembly, to layout, then sewing and finally how to make it work with the LCS.  Video below.  -13

Worm bin notes: Update 21 Where did the black solider flies come from?

Bins 2 & 3, Update 21.  Hard to believe it’s been a month since checking the bins.  I’ve been busy catching up on projects, updating supplies and equipment.  In update 20 I had placed some pupae into a canning jar to contain them in an effort to identify them as shown in the photos below.

In my mind without scientific proof the photo below shows black solider flies.  Wish I had remembered them before they died.  I would have let them go to reproduce later so they could have benefited the area.

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Bins 2 & 3 were in the same state.  The ambient temperature was 88º with a soil temp of 80.9º in both bins.  I forgot to look at the humidity percentage.  There were no odors or any food waste left in either bin.  There was a short break in the ambient temperature the last few weeks due to the volume of rain we had the heat is due to return with highs in the lower 90’s.  I fed the bins fresh and decomposing waste.  Also added some packing cardboard to see how that turns out.  Since the waste used to feed the worms is kept indoors and the bins are kept in a screened in porch where did those solider flies come from?  How did they get into bin 2?  -13

Latest video blog below.

Defensor Fortis LCS Belt Keeper & Flashlight Holster PALS modifications.

Time for some gear updates.  After switching from my old favorite ALICE LBE to MOLLE DF-LCS I experienced a couple of issues.  When using the LCS it would inch it’s way over my pants belt and push down creating discomfort.  I also noticed when in a sitting, crawling or in a prone position the rig would tend to climb toward my chest.  After thinking of a solution the only one I could think of was to attach straps that would keep the LCS from moving away from my waistline.

IMG_5445

Right segment of DF-LCS before adding belt keepers.

The idea came from my experience wearing a duty belt with belt keepers that were designed to hold the duty belt in line with my pants belt.  With this in mind I measured the area I wanted to place the keepers, doubled the length then added a inch and a half.  The extra length would give my fingers a place to work the snaps I intended to use.  Once I had the dimensions for the strap I cut six lengths of poly webbing, folded them in half and sewed them so the two halves would work as one.

IMG_5466

Right segment of LCS after belt keeper straps were added.

 

After sewing the keeper straps together they were sewn onto the three segments of the LCS.  Next the holes were punched then the snaps were added.  It was an easy project taking no more than 45-60 minutes to complete.  After testing the idea seems to work well to prevent the LCS from moving around and causing me trouble.  The LCS rig still has some movement/flexibility however it won’t move away from my waistline.  I made a short video, the link is below.

 

IMG_5459

I also modified what was labeled as a MOLLE flashlight holster to meet PALS specifications so I could attach it to my quick response belt.  The holster had the vertical snap strap but did not have the ladder webbing.  To fix this issue I removed the belt loop strap, opened the sewn seam to join the holster, added the new ladder section, then sewed the piece back together.  Time spent was about a half hour.  I made a how-I-did-it video the link its below.  -13

Worm bin notes: Update 20 Things remain the same

Bins 2 & 3, Update 20.  The heat is still on high in south Florida.  There has been small break during the night hours when the temperature reaches the mid to high 70’s.  It’s not much but I’ll take it.

 

As mentioned in my last notes I would gather several of the pupae I suspect are black solider flies and confine them so that if something does emerge from them hopefully it could be properly identified.  I put a few into a ventilated mason jar then placed it back into the bin.  I’ll leave in there for the next several weeks if nothing happens then I’ll put them in the outdoor compost bin.

The above set of photos are the exact same ones from update 19.  I forgot to refresh the weather page so the video has incorrect information for the ambient temperatures.  The estimated temperature was 87°F with 89% humidity.  It was very wet feeling this morning.  My shirt was drenched with sweat before I was finished.  Surprisingly the bin internal temperatures were exactly the same as last week.

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Bin 2 had no odors nor many spiders.  There were worms on the ledge.  I think it was getting warm in there.  Maybe they were trying to cool down.  It looks like all the waste had been consumed.  There was a roach(palmetto bug) in there that was dispatched to another place and time.  Sure hope there aren’t any eggs in there.  Bin 3 had a slight odor from the left over mango.  There were a few spiders in there it looks like the heat is effecting them as well.  They usually fill the bin quickly once they find a way in.

blender food

I’ve managed to burn out one blender feeding the worms.  I have a spare in storage but it is buried in our storage unit.  I’d have to remove most of the contents to get it.  That’s not going to happen anytime soon so I purchased a new one that already smells like it won’t last through the next cycle.  I may have to rethink my plan.

I usually put vegetables like carrots that take a long time to decompose in the blender to make it more accessible to the worms.  Items like avocados and fruits get cut up and placed in the bin mostly whole.  Those items typically don’t need assistance, root vegetables usually do.  When I do use scraps put into the blender I place the waste in a thick layer covering half or less of the surface.  This helps the waste maintain moisture preventing it from drying out before it gets consumed.

I’ll check in with the bins in a week, week and half and see how things are progressing.  -13

Project video below.

 

 

Worm bin notes: Mosquito Net Frame

Better late than never?  Over the last few years I’ve had to bring the worm bins into the house due to hurricanes expected to hit our area.  I roll them over a ramp from the porch into the living room where they stay until the danger has past.  Each time the house was infested by spiders within days.  I think they detect air movement and move to those areas then start spinning webs.

After a friend was bitten on the forehead by an unknown species of spider I’ve been reluctant to bring them indoors for fear of someone getting bitten.  There are many species of spider found commonly here in Florida that we frequently encounter.  The bite wound my friend experienced left a scar that cannot be denied.  It’s very concerning to not know what species it was.

spider bite

Unknown species spider bite wound. Florida, USA

With that knowledge I couldn’t put others living here at risk.  After thinking on the topic for a while I came up with the idea to make a PVC pipe frame then cover it with mosquito netting to contain the spiders within the confines of the enclosure.  The PVC pipe should work well for this purpose, it won’t rust, is lightweight and can be put together without fasteners or glue.  That makes the frame collapsible for easy storage and portable.

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I chose mosquito netting made for a bed.  It’s not heavy duty but should work well.  As best as I can tell the netting does not contain any insect repellent that may interfere with or kill the worms.  I’ve seen people buy mosquito netting for outdoor/camping use that killed their insects because the net contained repellent.  I chose this particular net because it completely encloses the space without any openings.  Plus the net was less than $12.00 on Amazon.  An affordable way to experiment.

To construct the frame I used 1/2″ pipe and fittings.  I used 90° elbow tees on the corners, regular tees for support members and legs as well as slip caps to cover and protect the leg ends from damage and insects or wildlife.  All fittings are dry fit so it can be taken apart easily since it won’t be used much.  The cost of the pipe and fittings was $20.94 purchased from Lowes.

frame

I started by measuring the areas I wanted to cover then cut the pipe to size.  Once I cut them I put the frame together.  Once together I cut the top cross-members to fit the frame.  I installed the cross-members without fittings since it would be much easier and give me the ability to move them as necessary.

net2

Net sag.  Lattice may be the solution.

Once I had the netting installed it became obvious that a piece or two of plastic lattice would work well to help support the net to keep it from bridging the moat.  The lattice would allow good air circulation.  I see scraps in trash piles regularly so the next time I spot some I’ll recycle it for the project.

net1

I purchased enough materials to extent the frame for one more bin setup.  If I add another bin I’ll make the extension then.  For now I’ll store the materials until needed.  Overall I’m satisfied with the outcome of the project.  The real test will be to bring the bins inside the house and see what happens with the spiders.  The population of spiders is minimal presently so an experiment at this time is premature.  Total cost for the project was $32.93.   From staging the materials to clean up the project took approximately 40 minutes to complete.  I’ll post an update if I test it or modify the project. -13

Short project video below.