Help with a Ditmar

Hi,

Just found similar lantern to this. I tried to pressurize the lamp. It gathers pressure about 1,5bar but I can hear the air leaking thru the valve up to the tip of the gas tube. Is the valve suppose to close the gas totally or is it normal that it leaks a bit? If not, any ideas how to fix the valve?

Best Regards

Veikko

 

Ditmar 520 Maxim

Hi,

Does anyone know the structure of this valve? If it is leaking in closed position, how to fix it? What kind of seal is used in this valve? Does the valve nut marked with arrow in the picture have opposite direction thread compared to standard?

And another question: I have tested the valve only with air, not kerosine inside the tank. Could
this have affect to the leakage problem?



Best Regards,

Veikko

 

Welcome aboard!

The link below shows the instructions for Petromax lanterns, but they should be fine for your lantern too, the library is only open to subscribers.

https://classicpressurelamps.com/threads/petromax-821-826-523.12238/

 

I think you should do some study on how pressure lanterns work. ;-)
This model has no rapid and no shut off valve. So you can not "store" air into the tank before lighting.

This model needs pre heating first and then slowly being brought up to pressure.

 

Welcome to CPL @Veikko
As WimVe said, it isn't a shut off valve.
The wheel turns an eccentric spindle that operates the jet cleaner. The arrow on the face of the wheel should indicate the position of the cleaner.

Nice looking lantern.

 

Almost all of this kerosene/paraffin fueled lantern is technically very similar to the common Petromax lanterns, and can even be replaced with available spares, if necessary. However, there are some details which might need special attention.
The "valve" you refer to is the eccentric drive for the cleaning needle of the jet. All threads there are right hand. The only seal is the carbon packing of the gland nut, which in case of a defect can easily be replaced by a sufficient amount of PTFE (Teflon) tape. The seat of the gland nut assembly is simply a brass metal face which needs to be fastened tightly.
As already said the lantern needs alcohol preheating without being pressurized, otherwise liquid fuel will leak from the jet, causing big trouble once ingnited.
I can only emphasize the advise to study on how pressure lanterns work (in particular the preheating procedure), as WimVE already mentioned.
Regards, Martin

 

Thank you very much.

 

Hi, thank you
for the info.

I must say that these lamps are quite physical marvels. Pressure, chemical liquids, thermodynamics, radioactive phenomenoms and so on...Lot of things to learn..

 

Denatured alcohol for preheating? In general have you used these lamps inside house or just outside?

BR,

Veikko

 

Hi @Veikko , welcome on board!
Everyone will have their own opinion regarding the indoor use of these lamps. One important thing has to be considered. In the days when most all manufacturers made indoor pressure lanterns houses were not build "air tight" like more modern homes. There was always a lot of draft so any smell was not really detected, or was not very strong. For indoor use I'd recommend lamps running on clear petrol (white gas, Aspen4, panel wipe, Coleman fuel etc.) or alcohol as they don't smell that much (I have used both petrol and paraffin pressure lamps indoors). If using a paraffin/kerosene one I'd recommend to light it outside and bring it indoors when fully heated and burning clean.

 

Thanks for the advice...Yes got the "mechanism" open. It really is just an up down crank...Here is a picture of the system..

 

Which area of the pricker control / eccentric above is leaking? Is it the threaded part or around the stem?
The threaded part usually don't require any sealants once tightened enough.
If its around the stem, then the graphite packing is compromised or the pricker control stem is worn or has an uneven surface or the gland nut not tightened sufficiently.

 

I don't have a 520 but the Non return valve at the bottom of the pump on yours could be the same

The thread on the NRV is 11mm (RIGHT hand thread).

The thread on the barrel of the NRV is 6mm (LEFT hand thread). A real trap to watch.

 

Hi,

I think this lantern does not have such part. At least I didn't see that kind of part when I disassembled the lantern?

I also replaced cylinder leather piston from the pump.

Before...


After...

 

Btw any tips for installing these mantles?

 

Too big? Should I supress the lower part with something or tie it up from higher position?

 

Are you saying you have not got a non-return valve (NRV) in the bottom of the pump tube?


[photo: @ROBBO55]

Tony

 

Oh.. it's that in the picture...Yes there is a valve in the bottom of the cylinder...first thougt that part in the pic to be somewhere else...Yes there is that NRV and I think it is working properly...does not leak pressure outward...

 

Everything fine with the size, maybe even too small. It fits the right place, and should thoroughly be straightened around the rim of the burner nozzle in order to avoid asymmetric shaping when burnt off. It will shrink massively when it burns off and even more when it hardens in the flame once the lantern is running.

 

Ok, thanks.

Do you keep this hat on or off when you start the lamp?

BR,

Veikko

 

It should be in place - many of us have found that the way a lantern behaves is quite different with the top cap or vent not where it should be
Sounds like you my be lighting up soon ? - when burning the mantle for the first time do it outdoors as the smoke from the mantle is not very nice..

 

Yes Uuu-Haaa....Pretty bright must say!

 

Congratulations

 

Looks great! You better get it in the garden with a congratulatory beer now

 

Thanks for everyone for help.
Yes! Beer can is already open (actually several of them).

Nice feeling to start it up first time.

Thanks!

BR,

Veikko

 

Works perfectly, now I started the lantern without the hat. Works well that way too. No smoke during start. I wonder what is the heat power output of the lamp?

 

You can estimate the heat output from the fuel consumption: 1 l of kerosene/paraffin contains about 10 kWh of energy. Burning 1 l in 8 h would therefore produce a thermal output of approx. 10 kWh/8 h = 1.25 kW or 1250 W. The relatively small power portion of the light output can be neglected.
So a quite reasonable heating. Obviously, the shorter the burning time for the same amount of fuel, the higher the thermal output.

 

Ok, yes 1250w is quite good. I was thinking to make a metal box (open from two sides put the lamp inside the box and add chimney on top and put it in to my boat cabin? I think that power would be enough to warm up the cabin? What do you think? Light and heat with one solution?

 

Using such a lantern in a closed environment such as a boat cabin, a camper van or even a tent is really not a good idea. It will consume all the oxygen in no time, and may also emit carbon monoxide (even more the lower the oxygen level around it gets), which is extremely dangerous.
Even a kind of a chimney as you describe will not really help with that matter. Besides this, most of the warmth will escape with the exhaust gases. There are also lots of cases known where people were killed when using such kind of appliances in closed environments. So please beware (or you will wake up one day and find out that you are already dead)!

 

Yes, you got a point there. I was just thinking that this lantern has about same heating power as Refleks boat stoves Oil ovens from Refleks | Choose a stove suitable for you and they also burn diesel (kerosene). Yes perhaps not good idea.