I was servicing an Aladdin 1A and took a few photos which may be of interest. I tried to show that old pips inside Non-Return valves (NRV) are shot and should be replaced. I have not set out to write a treatise on this subject. I was shocked by how little the old pip squashed and pleased with how much, about 40%, the new one compressed. Old pips also do not have nice flat surfaces to seal against the NRV lower part. The old pip is pretty well damaged. Here is where the parts live. The parts inside the NRV. (Note: The lead sealing washer is missing; often stuck in the pump tube.) Here is what the lead washer seal looks like. When tightening again in the pump tube it will seem tight but a little more force squashes the lead a bit more. It's a judgement call; too much and you may damage the pump tube. To extract the NRV you need a remover but there are different sizes. The following is only the size of an Aladdin 1A or Aladdin Two-Burner stove fitting that is on the end of the NRV and which the removal tool locks onto. (Some have slots instead too.) The removal tool must be a close fit, (in the above case 5 mm), otherwise you strip the raised piece of brass and it's 'all over rover'. These are some of the tools and you can make some yourself by using a cut off wheel from a grinder to cut a parallel slot of the right size. Others have a shape that fits the end of the NRV. The variety of tools often needed to extract and replace Non-Return Valves. The long grey one (Aladdin) has a homemade fitting to centre it inside the pump tube. This is what the end of the grey one looks like. Below is different one: The whole exercise is to keep the force on the NRV and not to let the tool slip else damage to the NRV occurs. Sometimes they require soaking in a penetrating oil for a few days before hand too. A final reminder is that ordinary rubber works, but only for a while. Viton rubber is the best and you don't want to be having to replace the NRV one too often, so Viton is the go. Good luck PS The ad on the right (from our site sponsor) is from the Fettlebox which supplies high quality washers and pips for most makes.
Whenver I get a new (to me) lantern I change these. Love the viton and expect them to outlast me ! I have in the past resorted to cork seals (and found them in some lanterns) but they don't last too long. I suspect that I buy cheap wine !
I've had a number of very old stoves that the NRV still sealed amazingly, so when checking them, they are like your above example. Many that fail are rock hard. Seems my Primus 96 stoves have the worst stuck NRV's in the pump tube. I got lucky last Fall and had a non-rising tool made for me that gets my most stuck NRV'S out now, still scary on how much force is needed to remove NRV'S from 100 year old stoves. Duane
I have recently found a nrv that I suspect may be made of cork as it doesn’t fit the bill of synthetic rubber type pip jobbies.. But how do I tell if it is cork or not?
@podbros I’ve come across many cork NRV pips. They usually look brown and crumble rather easily, rather than remain rock hard like old rubber. If you want to keep a cork pip in situ, soak it in neatsfoot oil and it should go soft. Rubber won’t. Cheers Tony
