Svea 123 Research Project, prelim

Hello,
This is a request for information for a research project.

This started with the making of my second generation of pentagon tools for removal and repair of the pressure release seal disk in Svea 123 lids with pentagon set screw. Soon the work had expanded to more testing and research. I plan to compile a more comprehensive post on the topic later.

Thus far I have taken a lot of data, and logged it for numerous 123s, including internal dimensions and spring details. There are also multiple data charts for pressure release averaging etc.

A new punch was made for the pressure release nitrile disk, .210 inch ID, external 20 degree edge.

A new punch and alignment tool were made for the lid seal nitrile washer.

Testing of lid safety release pressures and data logging is in process for the entire series.

There were spring changes after Sievert, the pressure probably changed as well more testing & data logging TBD. (Sieverts release at 70PSI average, with a hard nitrile they can release at 40 PSI)

A tank pressure monitor for a running stove is in process, it will be a special lid with pressure gage ports. Pressure and temperature data logging TBD.

Drawings were made for 6 lid styles, the Sievert lid drawing, lid types 1 to 3 is included in this post. The Optimus lid types 4 to 6 drawing is done but internal measurements need confirmation.

Adhesive is found on some Sievert pressure release disks securing them to the bucket. (type 2 and 3) More research required

A possible adhesive is a rosin based formulation with vegetable oil, methanol, and Kaolin clay.

Sealant/thread lock is found on Sievert pentagon set screw type lids. Some with a green color, one with metallic blue. The green material may be a rosin based type. Two microscope photos below.

There’s a lot more.

If I post a document with the proposed data and more, including stove photos then I would like to have the best dating information presently available, so I am asking for help especially in that area.

Thus far:
1. 1955 starting date Sievert Svea 123, type 1 lid, ornate key same as Campus 3, key parks on the vertical pin located on the windscreen IR shield brass disk

2. Lid changes to type 2, date unknown

3. 1958 still has the ornate key per 1958 catalog

4. 1958-1960 key transition - ornate key on 1960 catalog overview page 2, changes to the long key shown on page 16. Pressure release cap appears to be type 2 on page 17. Ornate key still shown on spares page 17. The key is now parked in a hole in the windshield IR shield disk with the pot handle and folding pricker.

5. 1969 or before lid has changed to type 3 pentagon set screw.

6. 1969 Sievert line purchased by Optimus

7. 1970 Optimus is shipping Svea 123 with type 4 lid (type 3 with single knurl, no text on lid) shipping in Sievert’s Red/White box, with same key as older type Optimus model 8, and all stamped text is removed except on the tank.

8. 1971 Optimus Svea 123 box is colorful with outdoor cooking scene

9. 1974 Optimus Svea 123R introduced, latest key type ( triangle ended), colorful outdoor box has yellow sticker “New with self cleaning device” Folding pricker is no longer supplied.

10. 19XX Optimus Svea 123R New box, light blue with mountaineering scene labeled “Climber”

11. 19XX Last of Optimus Svea 123R produced

12. XXXX Svea 123R Production resumed, manufacturing in Japan to present

Any and all help would be appreciated
Regards,
Doug

 

Excellent research! Thank you very much, I have learned a lot. Who knew such a little simple stove could be so complicated
Great work

Are you going to sell the pentagon tool by any chance? I have been thinking of making something like this too.

Cheers,
Jeff

 

Nice job indeed!

What will be the maximum safe pressure for a stove like that? My guess is 40 PSI should be enough, and 70 far too much.

dsk

 

Hello,
Thanks David for the photo editing & tips. I will likely try the thumbnail method next go around.

Jeff you have a P.T. on the tool query.

Dsk, not sure yet on the operating pressure as yet and I think 40 PSI is possible, but it might even be as low as 20 PSI. Let's find out, yes ? It is sure to give very interesting results, however this plays out, likely with more information gained than expected.

I am hoping to machine an adaptor that allows use of the wind screen during the test. This is a lot harder to design but would give real operational results at temperature with normal airflow characteristics. The adaptor will likely be 7/8 hex brass machined like a lid on it's underside. It will need 3 equal spaced ports to accomodate rotating to correct lid seal position with two ports to be closed off with an O-ring or nitrile disk under a screw head in a captive counterbore for the head to prevent seal walk out, one port to be accessed with a machined tube with matching characterisitics to the 2 closeoff screws, and about 2.5 inches long, entering through the unused key port in the windscreen nearest the lid/adaptor. The outboard end of the tube would have a standard tapered thread for the gage and include wrench flats for ease of installation in the adaptor after the windscreen is installed and before firing. I think the gage tube should be steel for strength due to it's length and relatively small screw thread on the adaptor end. This is somewhat dangerous but it is only for testing with short term controlled use. It would be easy to pre-pressure this device as assembled for test but without the gage installed, and submerged in water for a bubble test before firing to ensure no fuel/vapor leakage will become an issue. Of course this would be an outdoor event upon firing.

I would also like to get results for paraffin stove tank pressure in operation, as an offshoot to the present experiment.
Regards,
Doug

 

Probably quite equal pressure for several burners, a list made by an earlier supplier of spareparts states the part no. 2912 is suitable as cap on:
55 155 111-(all) 85-loke ranger-10 Hunter-8R 123 199-Ranger. I believe the 155 with gauge releases at approx. 36 psi, and closes again at about 30 psi. But those gauges had probably not the best accuracy.

dsk

 

Hi Dsk,
That is interesting information. So it must have been a relatively small gage integral with the lid. I would enjoy seeing a photo of that gage/ lid if you have access to one or to the literature.

My lower values in pressure testing were down to 40 PSI but these were the result of very old and hardened nitrile seal disks. There is more testing to be done (TBD) to get enough data for submittal of a range and average values. After replacement with a new seal disk of medium durometer hardness value, the release pressure changed to 70 PSI or just a little under that. Release pressure status detection is easiest with a finger over the vent hole instead of bubble test which subjects the steel unplated spring to rusting on Sievert lids, so the real values are probably a little less than what is detected using the finger method. There may be some other suitable detection method to be stumbled upon later on as well.

The computed pressure release based on physical measurement is 63 PSI with a measured compressed spring force of .9 pound and .01463 square inches of pressure seal disk surface (confined by the peaks of the 1/2 toroid machined shape at the bottom of the pressure release component well in the lid).

Based on a release at 63-70 PSI one might expect operating pressure to be 1/2 of that. The gage adaptor should tell the tale we want to hear about.

Thanks & Regards,
Doug

 

All above my head, but seems I remember that oops56 has constructed a tank pressure gauge of some sort. Maybe he will chime in with his thoughts/ideas.

Best,
Bob

 

Hi Bob,

I think I remember Robert mentioning pressure but believe he was testing when the lid will go into safety release due to over pressure. It was a about 2 years ago so I'm not sure, and he may have posted something more recently that I haven't seen. I made the pentagon tool for him and it was at the time of the first revison level on the drawing, 7-16-07.

It should make more sense when all of the info being gathered is combined in a new post with dating, fettling, and operating details outlined in one place.


Regards,
Doug

 

hi Doug
i have dabbled a little with testing SRVs nothing as elaborate as you are doing, mine was just through worrying myself about the use of old untested caps (i had one go to over a 100psi and still not release ) internal link if your taking orders for your tool could i please put my name on the waiting list i filed an old allen key till it sort of fitted but would much prefer a proper tool at the moment for use i tend to stick with the older slotted caps as they are easier to service

Bill

 

Hi Bill,
Yes, I had one that released too high as well. It went above 100 PSI, but it had the wrong spring which is likely a replacement put in by a previous owner. That would have been an unsafe stove if left as is. I made a new spring and it released at a normal value. Some tested lids had a breakaway at high pressure like they were stuck, then released at lower pressure. After that I used a pin to unstick them and added a drop of oil before test.

The link to George's comment was spot on, & thanks for searching it out for this thread.

There are a couple of tool requests, & will contact you.

I plan to refurbish most of my 123lids with new seals then do lid pressure testing again, logging results in a tabulated chart for comparison.

Also plan to do a few run tests, with a pressure monitor lid adaptor, an ambient temp probe and a temp probe on the top of the tank, and maybe one on the bottom of the tank. The stove under test would have a pot of water on top, probably the largest Sigg pot, 1/2 full, and it is quite important that it be run with the wind screen attached which makes the lid adaptor with a pressure gage more complex. My last test like this was an Opti-96 with a 1 pint burner on a special adaptor. In that test I let the water boil off. Next time I will keep the water the same so the stove sees the same thermal load.

I couldn't find the photo of the test setup of the 96, but have inserted the graph for review. This is how I will log the run test data for 123, probably 3 separate tests, Sievert Sv123, Opti Sv123, and Opti Sv123R. I would like the ambient to be 80F or higher for a full stress test. This graph for 96 below shows that a 1 pint burner on a 96 is inherently dangerous, especially when fuel is running low. The data starts after prime and just when the burner is operating.

Now wouldn't it be interesting to see how a 123 runs with temperature monitoring presented in this format -AND- the fuel tank operating pressure shown as well ?

 

Good Evening, Doug,

Outstanding stuff, my Friend, as usual!! I love your attention to detail, and very much appreciate your willingness to share your research with all other Stovies, world-wide!

If you DO plan to make those 5-sided tools, please put me on the list for one! That would make a valuable resource for the stove tool box! Thanks, again, and God Bless!

Every Good Wish,
Doc

 

Hi, I have been away for over a week and was delighted, on my return to find Doug Weise had posted again on CCS after a long absence.

Welcome back Doug!! It is great to have your input again.

I remembered the temperature graph you produced for the Pr.96 operating with a burner from an Pr.210/Op.00.

I dug out the comments I made at the time, just to show how much I had enjoyed your "experiments" in the past ( and how much I look forward to your future work):


Hi Doug.

1. You have been to a lot of trouble and have produced very professional scientific results, for this test.

2. On this particular test, the fuel tank, and its contents did get very hot, the question is does this matter?

3. Well, towards the end of the 90 min test the top of the tank was over 190 deg F, around 90 degC., and the bottom of the tank was not much cooler.

4. In other words you could almost boil water on the top of the tank, and you certainly could burn yourself on contact with the metal.

5. I don't think "normal" paraffin pressure stoves operate that hot.

6. I bet the stove self-pressurised once you started it!

7. The good news is that Kerosene does not boil until about 150 deg C.

8. The bad news is that the flash point of kerosene is only 43 deg C., so if your stove's fuel is released you almost immediately have an explosive mixture

9. With our particular Hobby we assume that the people buying and operating a stove are aware of the hazards and take appropriate precautions. However you cannot legislate for idiots or the uninformed, so you would not want to have one of these Frankenstoves fall into the "wrong" hands perhaps at some time in the future.

10. I believe your test conditions were not the most onerous and if, for example, one used a large diameter fry-pan in a sheltered position, temperature would probably get higher and more quickly.


Once again, Welcome Back!

Best Regards,
George.

 

Hi George & Thanks for the welcome.

Yes, the chart was a demo of how the format for a 123 stove test might look, and also a warning sign regarding stove modifications.

Prior to the time George responded to the original chart, we had discussed the adaptor drawing, and it's design, and machining hurdles that needed to be surmounted. It all looked pretty good on paper. Then a test was run and I sat there for 90 minutes writing down temperature values every 2 minutes. Then the chart was created in CAD software and temperature values were plotted as points on the chart with a fair line drawn through the points to show each temperature probe's reading for the full term of the test. The adaptor no longer looked good on paper, I sent the chart to George, and he got the same queezy feeling about the results. You can read the queezyness between the lines of George's response. The project was scrapped.

Now this time around I am building on the experience from that test, and still have the measurement tools and some good ideas about probe attachment that I didn't have back then. So......... a similar test can be run on the 3 types of standard 123s just to see what exactly is going on by using a digital temperature probe on top of the tank showing tank temperature, a probe on the bottom showing fuel temperature, a probe to measure the ambient air temperature around the stove, and the tank pressure can be monitored during the test run.
That's the plan right now.

The GOAL:
If I get all of the operating data I am looking for together with correct dating information,and with photos of the various 123 types and their components/accesories, and the various boxes that they were packaged in, then I will post it yet again, hoping it will get into the Mastercalass section as a reference.

That said, the query is still does anyone have dating information to correct or fill in the blanks in the first part of this thread ?

I noticed yesterday, that Wikipedia suggests Svea was purchased by Optimus in 1970. I had 1969 listed as the year, but I think it should be 1970 based on Wikipedia and the 1970 Red/white box notation in my dating list.


Regards,
Doug

 

Hello,
The lid adapter for pressure testing a running 123 is completed.
This is the drawing for the part.


Here are the basic parts.


This is the basic assembly, but the gauge tube must install after the adapter is on the stove.


This is how the adapter fits a stove.


This was the first trial to check the adapter.


The top tank temperature probe was positioned on the high area of the tank, near the riser/vapo setup. It was probably receiving a lot of infrared from the burner above, and my max temp reading once the stove was running at maximum output was 245 degrees F. I think I will place that probe in future tests at the top of tank/windscreen junction to hide it from burner IR.
The bottom temperature probe was under an edge of the tank bottom. It should be attached to the dome under the tank 1/2 way between center and the edge I think. It maxed out at 75.3 degrees F.

I ran the stove for about 15 minutes total, adding the pot of water at about the 1/2 way point. The maximum tank pressure reached about 22.5 PSI. I will be changing from the 160 PSI gage to a 45 PSI type to get better resolution and hopefully more accuracy.

Upon shutdown, the tank pressure increased to 25 PSI, then lowered as the stove cooled itself in open air.

So far, so good I think. Next will be some monitored test runs with data taken for charting.

Regards,
Doug

 

Fascinating stuff! A bit advanced for me though, but I'm hoping to learn as I could do with fettling the safety valves on my old ones.

It did prompt me to get down my 3 123's for a closer inspection.



I've seen these boxes with 'Made by AB Optimus' on the lid - this one doesn't have that & it came with this Svea instruction sheet. It has no inscription on windshield or parts. I think the early Optimus ones that used this box came with similar sheet but with a plain black band printed along the top - where the Svea logo used to be. When the R sticker came in is I believe when the standard style Optimus instructions kicked in - they were certainly available with that sort of box.

This one is a bit older



Again no inscriptions anywhere except on tank & this is the filler cap:



My last one has no box but all the markings & a type 3 cap.

I'd thought the box with the black & white photo of the guy in the check shirt was earlier than my 'green label'. That's just an opinion based on me have a plain 123 in the green label box & Toshiaki having several fully inscribed in the box with the black & white photo.

http://www2u.biglobe.ne.jp/~opt00l/gsvea123.htm

Also shows the key holding pin on one of his examples.

I'm hoping to get some Svea paper from the mid 60's from a Swedish collector friend so will add to the site when I do.

I guess we need to get all these in the Reference Gallery too!

 

Found some old pics 'on file';

What I considered to be the first of the Optimus 123's with altered instructions.



The first of the 123R's - now with standard instructions

 

Hi Doug, Great work as usual! You now have a proper engineered set-up for your experiments. I look forward to seeing the results.
Soon, not only will you have the most complete collection of No.123s in the World, but you will know more about their operating characteristics than anyone else, as well.

The photography is first-rate.
Best Regards,
George.

 

It would be interesting to see the close ups of the green labels of a few 123's. It occurred to me this morning that on some models the green label survived into the post 69/70 Optimus era - Kerophile has such a label with Svea Trading Company on the bottom of the crest.

Many have no company name on the crest which may suggest they are from the 1966 to 1969/70 period of the combined Primus-Sievert era. Older ones have Max Sievert on the crest. Obviously the commin name on the Sievert, blank & Svea Trading labels is SVEA on the main part of the crest.

This may suggest a couple of chronologies;

A
1 black & red box (sievert) 1955-1966
2 green label (primus-sievert) 1966-?
3 orange & lemons (primus-sievert) ? - ?
4 orange & lemons (ab Optimus) ? - 1971?
5 whatever Optimus did 1971? -

or

B
1 green label (sievert) 1955- ?
2 black & red box (sievert) ? -1966
3 green label (primus-sievert)1966-?
4 orange & lemons (primus-sievert) ? - ?
5 orange & lemons (ab Optimus) ? - 1971??
6 whatever Optimus did 1971? -

 

All right ! Now we are getting some information to cobble together.

Thank you George. I conferenced with my temp probe expert last night, I can make direct contact on metal with thermocouple probes so will use the heavy type aluminum tape to hold the probe on the tank bottom. The second probe is an encapsulated resistive type probe so can be placed at the windscreen/top of tank junction. When the weather allows the documented test firings can begin. I'm using a pocket type Olympus Stylus 850 SW camera. It surprises me routinely & thanks for photo compliments.

Thanks Ross for adding your photos and input. All information helps with the puzzle.

Your lid photo with the slotted top cap is a type I have not seen before. I believe a co-collector here in US has mentioned that type. He has an array of 123s so I will be asking him to review this thread & comment. In the background of that lid photo there is an Optimus type twisted wire chain key. It may have been a Primus/Sievert invention but optimus carried it out to present.

I believe the box sequence is as follows, and will include whatever supporting notes I can piece together when I get my photographs completed.
1. Sievert corrugated, green label, red paper tape up over top of single flap type box top. Image of stove next to '123' on the box front. Ornate Sievert key on these stoves.
2. Sievert corrugated, green label, 4 flap box top, no red tape. Stove image removed, looks like letter 'U' after '123' on the box front. Long Sievert key (see Sievert catalog 1960) on these stoves.
3. Sievert Red/White cardboard box with the flannel shirt fellow cooking. Long Sievert key on these stoves.
4. Same box as #3 with date code on top flap 1-50-70. Text stampings removed except for on the tank and the key is the Optimus 8 type.
5. Cardboard box with lemon and orange fruit shown on top flap and labeled on top 'Made In Sweden' I see Ross has one of this type with the long key, mine have the Optimus 8 key.
6. Cardboard box with lemon and orange fruit shown on top flap and labeled on top 'Manufactured by: AB Optimus' These stoves have Optimus 8 key
7. Same box as #6 with yellow add on sticker 'NEW now with self cleaning device'
8. Light blue Climber cardboard box with rapelling climber.
9. Modern white cardboard box with cutout in side so stove is visible.

I will get together some photos shortly. Per Ross's note about the Optimus instruction sheet at the 123R transistion I can see I will have to go through the instructions carefully to learn what ever can be gained, and incorporate those details.

It is still unclear to me where the Primus/ Sievert connection plays into the sequence. I suspect it was during the era of the Red /White boxes. Of particular note on this, it appears that Optimus shipped 123s in the Red/ White box based on the date stamp on the box top, the use of Optimus 8 control keys with twisted wire chains, and the reduced text version of the stoves. I believe Optimus was using up the old boxes.

I would like to see more on the crest images Ross mentioned. The samples here have only 'Svea' on the crest.

Thanks all for your input, & aren't stoves interesting George ?
Regards,
Doug

 

https://classiccampstoves.com/threads/566

This is the label from one of my 123's. The stove is plain bar the engraving on the tank. (it's the one posted above with the slotted filler cap).

I think it has Max Sievert on the crest which using my current assumptions is pre 1966 - maybe a little later allowing for use of 'old stock' labels. I'll try & get a closer view of the crest & report back.

The box is plain cardboard with three flaps - 2 side wings & then one over the top that tucks in.