hello all,im new to the forum. wondering could anyone tell me about the inside of the tank of the max sievert self pressurising petrol blow lamp,especially about the safety device and how it works Any help much appreciated. Dennis
I assume you are thinking about the older style of safety release with a soldered safety pin? The safety pin is firmly attached to the bulgy bottom of the lamp. The other end of the pin is visible on the top of the tank where it protrudes through a hole. Up there it's sealed with a soft solder. If the pressure within the tank should rise to dangerous levels, the bottom (and probably all other walls too) will flex, and the pin is broken free from the solder on the top, meaning that the over pressure will vent out there. It obviosly worked since this device was used for a long time and not only on small blow lamps. Also petrol fueled camping stoves used the safety pin, and I have seen many that had been resoldered. (Once released, you just simply had to re-solder it.)
Aside from the safety feature, the central boss which extends from the burner body is anything up to about 1/2" in diameter. This contains a wick which is used to feed the petrol up into the burner assembly (which by nature also functions as an anti-pulsation and filtration device). A picture would help please. Earlier versions as as Christer says above, later versions use a sprung-loaded safety release valve, some mounted on the front face to project the flammable vapour away from the user, others have them on the top. Alec.
I agree with Alec. Post us a photo or two so we know exactly which model you are asking about. Later petrol lamps usually placed the safety valve in the fuel lid. Like this little dusty Max Sievert I found in the basement. This specimen isn't a self pressurising device, but it's the same size and they used the same kind of lid.: Below is how the most common of the smaller self-pressurised older Sievert blow lamp look like. You can see the safety pin exit the tank just below the burner so the flame will be directed away from the user, just as Alec says. I assume the position just below the flame of the operating burner also will help igniting the gasses that stream out when an accident occur. Better control with a small flame than letting out the gasses to form a cloud which might ignite with lesser control. The wick mentioned is generally reached from a plug under the tank, as seen below. But on some you must unscrew the burner feeding tube from the tank. Directly to the left (or rather at about ten o'clock) of the bottom hole in this picture, you can also imagine the lower attachment for the safety pin.
thank you Christer and Alec. You have been very helpful.Im not sure how to put up a photo yet however it is exactly the same as the one without the pump in the photos you put up.I would also like to change the gland packing but do not know what is best or where to get it. also wondering is the old packing or wick made from asbestos. Any help much appreciated.Dennis
The wick is just made out of cotton. Typically when making a new one, you just use a couple of strands from a regular cotton mop. The gland packing was graphite, so that's what you need.
You're welcome Dennis. You can also use regular plumbers tape out of PTFE to stuff the gland! Just roll a bit between your fingers so it forms a round thread. Then roll it around the spindle and pack it inside the box. It does also work with plain graphite from a pencil. I have atleast tried this with smaller glands, as on Primus lanterns, with good results. Just pulverize a bit of graphite from a regular pencil or better yet; a pencil refill. place the powder into the packing box and seat it. Sometimes it's best to unscrew the box nut once and add some extra graphite and reseat it.
Christer,can I trouble you again. You said about the tape and the graphite from a pencil.Do you mean use the tape first and then put some graphite in with it. Regards Dennis
No, just the tape or just the graphite. Try the tape. It's easier, and should work. The stuffing box is so short on these so you might need to pack it twice.
Christer, I used the tape.It worked well. I lit it today. I was terrified of it but everything went ok. thanks again for all your help. Dennis
My neighbour has one of them sitting amongst all the rest of his farming and construction business junk that lies around his property. It looks in a pretty poor state and have considered seeing if I can clean it up and repair it. I can take it if I want but with health issues such as they are at present I'm not wanting to take on too much. If anyone is interested in it I can clean it up and post it. Will post a piccie later once all the gunge is off it and it's a bit cleaner.
Yes Lyn, post us some pictures. That's always nice. Dennis, I'm glad it worked! How about some flame shots?
Hi Christer, it's sitting in a bucket of vinegar at the moment to clean it up. Will post some piccies once it's decent.
Hi Christer. This is it after a few days in vinegar, haven't tried to dismantle it. It's missing the on/off knob and not sure what it's like internally. Will post more piccies as I take it apart.
Nice. That's what they should look like. Nice and clean, but not over worked. I hope you won't fall for the temptation to polish it. This deeper, dark bronze look which only time can give, is much more beautiful than the yellow high polished brass. I think the control knob should like the same as on the one I posted that has a pump.
Lyn,it is a very nice looking lamp,seems in good condition.I hope you are feeling up to getting it running.Let us know how you get on, All the best Dennis
Hi Christer, no chance of polishing it, far too lazy for that. Might have difficulty with the knob but will make do and mend as best I can. Still haven't dismantled it but hopefully get on to that later this week.
It's practically the same as when lighting a lamp. Just without the mantle. Fill it with petrol, make sure the valve is closed and the lid is closed. Fill the indentation around the burners feeding tube with meths up to the brim and light it. You can pump it up during the preheating, or you can do it before. You don't need to pump so much initially. It's better to pump to increase the power once it's running. Once the meths is about to expire, you open the valve and if everything is OK, you shall get a nice flame. It's a piece of cake, and you'll get the hang of it very quick. To extinguish, just close the valve and make sure you'll keep the lid tight for a while. It's petrol, so we don't want any fumes to vent out before everything is cool and nice. Why dismantling it? It's not certain you need to dismantle anything. Give it a test first. That way you will see what need fettling without overdoing anything. These usually work without too much fuss. Perhaps all you need to do is oil up the leather and prick the jet, and what do you know! Bob's your uncle. But with a bit of bad luck, you might of course have a lamp that need most things to be fixed: the tank lid washer, the NRV etc. Even the wick might be rotten... But test it before you do anything. Atleast pressurise it and dunk it in water first to see if the NRV and tank lid gasket is tight.
Interesting! I have such a similar beast, but equipped with an extra tube - I imagine that I should put a wick in it and use it as an afterburner like on stoves?
Hi Christer, I've had to strip it down further as there appears to be a problem with the pump valve, also the wick/tape whatever that is used for appears to be rotten. Can repair valve but not sure about wick.
Well, try it first even if the wick looks like crap. It still might work. If you need to replace the wick, you can use a couple of strands from a regular old school cotton mop. There are plenty written about exchanging the wick in several places. First one I found was this one at our sister site. Even if it's about a stove, the process and material is the same.
