200A and 202 reproduction
frames back
in stock.

Guff
I thought I would post some photos and a brief discription of how to service a non return valve. This maybe a bit pic heavy and boring but the newbies may learn something from it.
You will find the NRV at the end of the pump tube and its purpose is to allow air into the fount to build up pressure and also to prevent air and fuel escaping when the fount is pressurised by the attached pump or by an external hand pump or compressor.
With lanterns, the NRV is mainly found on kerosene fuelled ones but some of the early Coleman models using coleman fuel also had them. The NRV  consists of a two part brass cylinder which screws into a threaded seat at the end of the pump tube. Inside the cylinder is a spring loaded cup which holds a fuel resistant cork or rubber pip and this pip is pushed against a small open ended nozzle which protudes into the pump tube. The spring provides a weak positive shut off when there is no pressure in the fount, thus preventing the fuel in the fount escaping into the pump tube. When the pump is pushed in the resultant air pressure created forces the spring loaded pip away from the air nozzle allowing the fount to be pressurised. On the pump upstroke the spring loaded pip and pressure in the fount forces the pip back against the nozzle again, thus preventing the pressurised fuel escaping from the fount.
This set up is different to the more common Check Valve used on most of the Coleman lanterns. A CV consists of a similar brass cylinder which has a steel ball enclosed in a cage which allows the ball a small amount of travel. When the fount is pressurised the ball is forced against the nozzle to create the seal and prevent the pressure in the fount from escaping. As a backup, Coleman added a brass screw on a brass stem (air stem) which screws into the pump end of the valve to provide the positive shut off required to prevent a loss of pressure/fuel from the fount via the pump tube.
That is how they both work, and hope I did not confuse you. The photos below will make things more clear.
Photo 1. A lantern pump with the NRV screwed into the base.
Photo 2. Two different types of NRVs, one with a slotted head the other with a nib.
Photo 3. Two home made tools for removing the NRV.
Photo 4. NRV being removed from the pump tube.
Photo 5. The different NRVs removed.
Photo 6. Taking the NRV apart. Be careful, it is only thin brass tube easily damaged, so do not force it. Apply heat to the threaded part and quench, if necessary. Heat may damage the spring but a spring from a ball point pen cut to size can replace it.
Photo 7. The innards of the NRV. Air nozzle, rubber pip, cup, spring and brass cylinder.
Photo 8. Making new nitrile, or cork, pips using a hollow punch to punch them out of the sheet. I make two sizes, 3mm and 4mm to fit different size cups. Trim the sides with emery paper if the pip is slightly too large to snugly fit the cup. Cork gasket can also be used for pips.
Well that's it. A bit long winded but it may be of some benifit to some when tackleing that leaking NRV.

Keith.




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deepcrete6
very nice Keith-great tutorial and great pics too
thanks, Jerry
*I saw weird stuff in that place last night-weird,strange,sick,twisted,eerie,godless stuff....and I want in -Homer J. Simpson
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Motor7
Awesome post...should be a sticky!
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Flat_twin
I thought the thread title was most appropriate.  The Ins and Outs of a NRV.

So you're saying...

Air should go in,  and not come back out?  

LOL!  Sorry, it just hit me that way.  Nice write up and pics or should I say pips?
Mark __________________________________________
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wsryno
+1 to Sticky.
Sometimes a lantern is just a lantern. Bill. ICCC #1430
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curlyjoe_99
STICKY, STICKY STICKY!!

do have a ???  on the punch out -Pic8- how thick is the sheet?
because I was toying with getting the sheet to do fuel cap gaskets of both 3-pice and one but these pips appear to be thicker
Robert (AKA Curly)-- Heart-of-Texas! "Keep 'Em Working"  
MILSPEC_OPS & 275 Appreciation Syndicate Member #9999

In Search of (ISO): evidence of a 220/228 series lantern dated 2/63    

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Guff
"Curlyjoe_99" I use 3mm thick for pips and 1.5mm for gaskets. You can also punch the pips out of the 1.5mm sheet, and just glue two of them together. Use a fuel resistant glue though.

Keith.
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tretrop
Big NO-NO in this picture, the slot is not supposed to take a screwdriver, you are risking damage to the NRV if you do this, I have and with bad result. You shall use pliers to hold the body and not us that slot. [023] 

https://d28lcup14p4e72.cloudfront.net/50792/1696247/023.JPG
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Chucker
@tretropWelcome to the forum .

I wouldn't disagree that you may have had a bad experience or two with that method however - I use the same method as Keith, @Guff above and have used on multiple lanterns and stove for years with no ill effects. 

This is not a high torque application so shouldn't need a lot of force to loosen or tighten. 

I would suggest if the brass gives way with a screwdriver the brass was weak and should be replaced anyway. 
Chuck
"...we also glory in our sufferings, because we know that suffering produces perseverance; perseverance, character; and character, hope" Romans 5:3-4
Eye-SEE-C-C Member #1333 -- MilSpecOps #003
"Michigan - from the Ojibwa word “meicigama,” meaning “great water.”
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gwillmot
I have found the "hardest" part is removal of the NRV from the air tube.  Any additional information you can give on your homemade tools .... thickness, etc.?  I've tried screwdrivers that were filed down to the correct "thickness" but with limited success.
Thanks
Moon Shadow Eliminator
[black-and-white-moon-images-8-desktop-background]       
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Guff
tretrop wrote:
Big NO-NO in this picture, the slot is not supposed to take a screwdriver, you are risking damage to the NRV if you do this, I have and with bad result. You shall use pliers to hold the body and not us that slot. [023] 

https://d28lcup14p4e72.cloudfront.net/50792/1696247/023.JPG


That's rubbish!  Did you not read my comments regarding Photo 6  (dismantling the NRV) in my post?
Here it is again in case you missed it, " Photo 6. Taking the NRV apart. Be careful, it is only thin brass tube easily damaged, so do not force it. Apply heat to the threaded part and quench, if necessary. Heat may damage the spring but a spring from a ball point pen cut to size can replace it." You must have used excessive force on the one you damaged.
You will also do damage to it if you use pliers to unscrew that thin walled body of the NRV. I would have serviced at least 300 of those types of NRVs, using the method I described above, and have yet to damage one by using excessive force. If I feel any tightness at all I apply a little gentle heat and you can usually unscrew the valve with your fingers only.

When fettling any GPA there is hardly any brass part on them you won't cause damage to if you use excessive force when you dismantle those parts. That is the case whether you use wrenches, grips, pliers, screwdriver, or vices as tools. We have all been there and done that when removing/dismantling valves from bungs, fuel caps, burner tubes, burner caps stuck generator nuts, vent studs, ect, ect... Refrain from using excessive force.  Apply a penetration oil soak, and heat and quench, and eventually you will get the item apart, but it may take several cycles to do so.

Keith. 
Edit. Corrected wording, valve bungs to valves from bungs. 
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