Operation of Steam Sterilizer

and any other non-chem subjects.
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Teddles
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Joined: 06 Jun 2019, 13:36
State/Location: VIC

Operation of Steam Sterilizer

Post by Teddles »

Query from a Lab Technician...

Recently purchased a new Steam sterilizer...The question I had was regarding the venting. The instructions say to vent twice yet the lab techs I have sought advice from on the LTAV forum don't vent at all - they have the vent in the open position when heating then after they have seen steam escaping for 7 mins they close it off and proceed to bringing it to the sterilisation temperature then sterilising for 35mins all which makes me wonder if they have a different version of the All American Non-electric pressure steam sterilizer (Model number 1925X, 24Litre).

Also, a clarification if I may... step 8 is "place unit on heat source. If the water you have placed in the unit is cold, it will require approximately 35 mins to bring the unit up to temperature." Then Step 9 is "Open Control Valve...". Does this mean I should wait for the pressure to build up to the sterilisation zone then open the valve or do I open the valve whilst it is heating on the hotplate and just wait for the temperature to increase enough that steam is being generated?

My other question regarding the molten agar - In my experience when rapidly decreasing the pressure from high pressure the molten agar boils over the conical flask that it is in. Is there a trick to preventing molten agar from overflowing? (other than only filling the conical flask 80% - eg 400ml in a 500ml conical flask with foil over it). Or is there some mechanism in this steriliser that safe guards against this problem (I've only used it once so far).

Suggestions welcome!!!
Merilyn1
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Re: Operation of Steam Sterilizer

Post by Merilyn1 »

I got taught in my TAFE course (Cert III) to open the valve and wait for steam to be produced for 5 (? maybe it was 7) minutes then close the valve. But, I agree, I've read the instructions and it does say to do things differently. (I'd have to get the instructions out to check what it says). The best thing would be to follow the instructions that came with the unit.

When you put it on the heat source, leave the valve open until steam starts escaping. It can take a long time, but you need to be around to keep an eye on it - ie don't go to lunch and leave it!

No answer to the agar over flowing, apart from not filling the flask/bottle completely. I use Schott bottles with the lid not screwed on. I've just bought the Youtility bottles that are narrower and easier to handle. I put water and agar powder in the bottle, lid on, shake it, loosen the lid, then into the autoclave to cook. Important you remember to loosen the lid!

Hope this helps
MariaQ
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Re: Operation of Steam Sterilizer

Post by MariaQ »

Hi Guys,

I just used the steam sterilizer I found in the back of the cupboard, after Westlab kindly sent me a manual as I didnt have one. I also am perplexed, but can only assume it's something to do with trying to "dry steam"??? I was worried that there would be no water left in the sterilizer, letting it vent twice, but it was fine. Im not sure Id bother again, Im going to order the autoclave strips and experiment. :thumbup: MariaQ
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melsid
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School: PHS
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Re: Operation of Steam Sterilizer

Post by melsid »

I use the All American, start heating with the vent open until steam escapes for 5-7 minutes.
If I put the agar into a conical flask I pack cotton wool into the neck then cover loosely with foil. I've never had a problem with it boiling over but I don't fill more than about 2/3 full. When I can I use the Scott bottles with the lids slightly unscrewed.
I also cheat and use boiling water to start with so it doesn't take as long to heat up.
And I set a timer to remind me that it is there!!!
Techie
Posts: 8
Joined: 03 Jul 2019, 09:35
State/Location: VIC

Re: Operation of Steam Sterilizer

Post by Techie »

Try this link for instructions on the use of the All american steriliser

http://www.allamericancanner.com/Autocl ... ilizer.htm

Cheers
harveyradar
Posts: 22
Joined: 08 Dec 2014, 15:36
State/Location: VIC

Re: Operation of All American Steam Sterilizer

Post by harveyradar »

Can those who regularly use the All American Autoclave Sterilizer tell me please what approximate number on the control dial their unit ends up being set at to maintain the pressure in the green zone.
I had to reset the dial control on a unit recently and the factory provided instructions where a bit too general rather than precise. Even though the adjustment was successful it would be useful to get an appreciation of how they behave 'normally'.
All American controls.jpg
Thanks
Harvey
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Merilyn1
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Joined: 12 Mar 2013, 08:10
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School: Wollondilly Anglican College
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Re: Operation of Steam Sterilizer

Post by Merilyn1 »

I think mine eventually sits around 6 to 7. I crank it up to start with then turn it back.
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KassH
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Re: Operation of Steam Sterilizer

Post by KassH »

I set mine halfway between 7 and 8 once it's up to the green.
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