Just finished making a mixing stick for my 4.2 CFM Walter-Kidde compressor, and after several attempts at making the stick different ways I figure I post what I did. Perhaps it may save someone else some fiddling time...
The compressor I purchased from Jim Shelden in Wichita KS, aka "frogman62" and works like a charm. I am now using Mobil's Synthetic Jet Oil 254, after reading a discussion in this board. 254 is 50% more resistant to oxydation than Jet II, good for EAN mixing... Thank you frogman for all the help !
A curious thing here in western Canada, is the lack of PVC parts, unlike for example in Lowe's stores down across the border. So, after much fiddling with stick diameter and possible baffle materials I happened upon the perfect fit between 1 1/2 inch household "drain" pipe and wiffle-balls. The balls fit smuggly into the pipe, so there is no preferential edge-flow between the balls and the pipe. Here in Canada the pipe is made of ABS; maybe in the States one can find it made of SCH-40 PVC. ABS is supposed to be more rugged, or so the guy at Home Depot said...
Another lucky find was the Hoover vacuum cleaner filter (see attached photos), it just happens to fit snugly into a 2" to 1.5" adapter (also ABS drain).
I have put a total of 6 wiffle-balls in the pipe, one between the filter and the oxygen intake, 3 immediately after, and another two before the sensor T. I hooked it all up and fired the compressor, and I could feel quite a bit of vacuum with my hand at the top with the filter removed. I have not measured the vacuum difference with a manometer at the compressor input, but that is next.
Given there are no 1" parts in ABS drain pipe I had to go to 1" PVC to make the T for the sensor. I used a 1-1/2" to 1-1/4" drain pipe disconnect, and a couple of wraps of electrical tape to connect the mixing stick to the sensor T. This had the added feature that allows me to take of the compressor stick-intake without dismantling the whole thing when I only need to pump air.
For my sensor, the inside of a 1/2" pvc pipe fits the sensor adapter perfectly, so it is just a matter of gluing the right length to the 1" T and then sawing off close enough to allow the sampling orifices to be in the gas stream.
The cap for the compressor intake is made of a 2" ABS pipe cap, drilled to accommodate a 1" hose barb. I glued a piece of 2" pipe inside the cap to provide a wider base for a better seal with a gasket on the top of compressor intake.
Anyway, I hope this helps someone.
The compressor I purchased from Jim Shelden in Wichita KS, aka "frogman62" and works like a charm. I am now using Mobil's Synthetic Jet Oil 254, after reading a discussion in this board. 254 is 50% more resistant to oxydation than Jet II, good for EAN mixing... Thank you frogman for all the help !
A curious thing here in western Canada, is the lack of PVC parts, unlike for example in Lowe's stores down across the border. So, after much fiddling with stick diameter and possible baffle materials I happened upon the perfect fit between 1 1/2 inch household "drain" pipe and wiffle-balls. The balls fit smuggly into the pipe, so there is no preferential edge-flow between the balls and the pipe. Here in Canada the pipe is made of ABS; maybe in the States one can find it made of SCH-40 PVC. ABS is supposed to be more rugged, or so the guy at Home Depot said...
Another lucky find was the Hoover vacuum cleaner filter (see attached photos), it just happens to fit snugly into a 2" to 1.5" adapter (also ABS drain).
I have put a total of 6 wiffle-balls in the pipe, one between the filter and the oxygen intake, 3 immediately after, and another two before the sensor T. I hooked it all up and fired the compressor, and I could feel quite a bit of vacuum with my hand at the top with the filter removed. I have not measured the vacuum difference with a manometer at the compressor input, but that is next.
Given there are no 1" parts in ABS drain pipe I had to go to 1" PVC to make the T for the sensor. I used a 1-1/2" to 1-1/4" drain pipe disconnect, and a couple of wraps of electrical tape to connect the mixing stick to the sensor T. This had the added feature that allows me to take of the compressor stick-intake without dismantling the whole thing when I only need to pump air.
For my sensor, the inside of a 1/2" pvc pipe fits the sensor adapter perfectly, so it is just a matter of gluing the right length to the 1" T and then sawing off close enough to allow the sampling orifices to be in the gas stream.
The cap for the compressor intake is made of a 2" ABS pipe cap, drilled to accommodate a 1" hose barb. I glued a piece of 2" pipe inside the cap to provide a wider base for a better seal with a gasket on the top of compressor intake.
Anyway, I hope this helps someone.
