I have a pork pie table lamp, noticed that the pressure indicator is recessed like it should be in the hole, but when i pump pressurise into the tank and the shaft comes flush with the hole i can see bubbles ever so slightly, is this normal. Not sure if its kero or air only, will have a better look next time, could i have over pumped it, could it be damaged and leaking, the pressure shaft goes up and down freely, but only noticed it the other day when it was lit for a few minutes air bubbles coming out the nipple, and the shaft in the pressure nipple was flush at the time i noticed the bubbles. Regards Darren
@Kiwiboy00 I had that happen recently in a lantern I had just dunked tested. When I stopped pumping the bubbles stopped. If the bubbles keep coming on your lantern I would think you have a problem.
The pressure bellows below the pip contain air so some may leak past when pressurised. If its a constant flow of bubbles you may have a problem.
I've had bubbles come out of the pip on a tank I'd had sitting in detergent solution to clean it, which stopped when it dried out- if you get liquid in the works( dunk testing , cleaning, spraying penetrating oil down there to free a stuck pip) it may bubble. If you haven't done anything like that, you may have a hole in the bellows, which is not good as they are (afaik) impossible to fix, the only solution being to solder over the pip to stop the leak.
If you do have to solder up the pressure indicator, then I have found that this method works, clean the outer tube back to the brass and then drill out the inner rod a little and then clean out the tube, the solder grips better to the clean brass.
I usually fill the recess with oil and pressure/release/pressurise a couple of times. That fixes it. I’ve not yet had to solder one shut. Tony
As @Tony Press said. I lubricate the indicator pin with some light oil. I’ve had stuck ones but not leaky ones. Sometimes the air in the bellows is escaping as the pressure builds up, as @KAB said, and this is could be the air bubbles escaping. Further as the temperature of the fount increases the fount’s pressure will increase and the bellows may respond by expelling a little air. Cheers Pete
Thankyou everyone you are all amazing and full of knowledge, so im guessing its some what normal to have a small amount of air to escape out the pressure nipple, i did not count the number of pumps but the pressure indicator was flush and not protruding, it was my Porkpie Table Lamp Tall Stem TL106 or TL116 ? I have heard that its pretty hard to over pump a PorkPie Table Lamp and damage the tank. Dose anyone know can you over pump a tank where it causes damage to the pressure bellows ? PS- I have porkpie table lamps, long and short stem, not lanterns. Kind Regards Darren
If this is the case, how do the bellows work in allowing air to escape, and how do they close off to stop continuous air loss. Im trying to get my head around why and how air can escape and is it caused mainly over pressure or leaking, as the pin when pumped is not jammed as it was flush with the hole. Then some say if i keep pumping the pin can protrude pass the hole. ?
The pressure indicator's tube is soldered to the pressure plate/bellows and sometimes the solder joint cracks and that causes leakage. This link shows a Tilley cutaway lantern and the bellows is shown clearly. Tilley X246 Cutaway (early 1950s)
OK here's a pic of the beast showing how it is made. Image by Dr T. Marsh. Hollow inside so when it is compressed it has to shove some air out. Normally you would not see this but if there is any moisture in the tube then you may see bubbles showing. That is quite normal. The diaphragm is copper and pretty flexible but might crack. However if it is cracked then the gauge won't work and push the rod up but it will leak air and drop the pressure in the tank. If you do ever play about trying to solder it closed then be careful. Warm things up too much and the whole thing will drop into the tank. This of course solves any leakage problem from the gauge but perhaps os not the desired result. ::Neil::
Good advice. I had a similar display of bubbles on one of my Pork Pie Tilleys. With no air in the tank I placed a few drops of oil on the pressure tit and then slowly started pumping the lantern. I did this two or three times and it cleared it right up. Dirt, I guess gets lodged in the thing and it won't work like it should. Give this a try before you do anything drastic, like soldering it shut.
Don't over pressurize the tank. Amount of pumps depends on the fuel level. I just pump until the light is bright. More pumps after that increases the time before a few more are needed. I find 50 pumps on a full tank is sufficient for Tilley lamps with the X246 style tanks.
Tilley didn't give the number of pump strokes to run their lamps until at least 1960 and it may only have been after X246B was introduced. They mostly say 15 pump strokes to start and then pump until the pressure indicator is level. With the B model because there is no pressure indicator they had to give some guidance so X246B instructions are where they say with a pint and a half of kero (30floz) 15 pump strokes to start and then a further 85 strokes to full pressure. Total 100. Since the tanks are about the same capacity those instructions also work quite well for all small tank Tilley lanterns from before model X246B. They cheated with the B500 series. That model instructions states a total of 150 pump strokes for full pressure. So they got the extra power from pressure not some magical tweak of the vaporiser and burner. ::Neil::
I must have picked up the (total of) 100 pumps from here somewhere in the dim dark past. In practice I never pump the indicator nipple past level with rim. But I’m very cautious with the late X246s and the As and Bs and only pump them until I’m satisfied with the light, and nowhere near 100. Cheers Tony
I have a simpler method with those. I just don't light them. Unless of course I am fettling one for someone else and then it will be run without a mantle and at a low presure. ::Neil::
