that's good to know, thanks for the clarification beats me how it can work both ways at once but clearly they have figured it out.
The original pump is simple genius. The grove on the plunger is wider than the o-ring that makes the seal. There are three crimps that intrude into the grove. The o-ring moves back and forth sealing on the down stroke and allowing air to pass on the up stroke. Quite an amazing piece of kit.
Headless T gunner is right. Pure genius... or at least it works and works well. Here are some shots of the clone next to the real genius (on top 1st pic and on the right in the 2nd) aka the short one. I figure one could use a punch to make this effect. Cheers, Jeff
Well I made the clone pump work as well as the original midi pump. By copying the three crimps like on the the original design. Strange why whoever made the copy/clone pump missed this feature. Sorry for all the posts. Jeff
Remarkable! I suppose we should not be surprised at the elegant simplicity of the pump design given the beauty of the burner design. I hope I can get my pump apart and make the indentations without messing it all up. The pump, the cap and the shipping cost as much as I paid for the stove! Thanks for posting the solution!
Sorry Ron. My current camera isn't great at macro shots. Looking for a new one but can't make up my mind. Here is one shot but it isn't much better than the one above. I will try again tonight. There isn't much to it. Just three punch marks that make a slight curve. Jeff
Jeff, thats just what I needed to see. So it works well now I mean with the pump on the cap, you can easily pull the plunger? Thanks much. now I have an idea, how about just doing a center hole all the way to the top. Your thumb could plug the hole when pushing it down Ron
OK, at the risk of betraying my noob-ism, how do you get the plunger shaft out of the cylinder? I took the threaded end cap off but the shaft remains firmly stuck in the cylinder. By the way, the powdered graphite lube really improved the action of the pump; it does not stick any more!
It should just pop out the end that you just unscrewed Sparky. I am glad it helped Ron! I can easily pull the plunder. Since the air is able to blow by the oring from the top near the knob. Jeff
Well, I just put the "fettle to the metal" and it popped out. I will fabricate an appropriate triangle punch and give it a whirl. I assume this punch pushes the lip downward, not displacing the metal outward?
You could just use a normal punch. but I look forward to your triangle punch. Yes the punch pushes the lip down and does not displace the metal outward. Just be gentle. I hope it works! Jeff
Jeff, my other passion is blacksmithing; I live to actually NEED to make a tool. Meh, it keeps me off the streets on weekends.....
Excellent !!! I don't know how many of these pumps are out there but you might be able to make a few of these tools. I have always been interested in blacksmithing but never got into it. Looks hot! Jeff
I don't want to butt in this interesting thread, but as a newbie also, I have this question, "Does the indent prevent the o ring from sealing against the lip?" BTW Sparky, I'm from Texas also...my grandfather was a blacksmith with bellows and coal. I still have his anvil. Jim
Great question That is exactly what the indents (3) do. The oring is forced into these indents on the up stroke and therefore breaking the seal. Allowing air to get by and fill the void left by the up stroke. Then on the down stroke (air going into the tank via the tank cap and tank cap non return valve) The oring seals stopping any air from leaving the chamber/void. And therefore pressing air into the tank. Jeff
