Greetings All,
I've been tinkering with my ideas for this model for some time, and now that it's nearly done - I just couldn't resist throwing out a couple of teaser photos until I have time for my first real smoke with it.
By now everyone probably knows that with the factory setup on the MES 30 Analog, airflow is nearly non-existent and non-adjustable. While it works and does what it was designed to do (more or less) - it's just not how *I* wanted it to work.
As the subject line indicates, this mod "sucks" - that is to say it uses a miniscule amount of compressed air and a homemade venturi to create negative pressure at the factory exhaust port, thus pulling the (hopefully clean) smoke from an external "mailbox mod" and on through the smoker cabinet.
The venturi consists of a 3/8" tee fitting, a 3/8" modified barbed fitting, and a short length of 3/8" brass pipe. The barbed fitting was modified by fitting it with a length of small diameter brass tubing.
Pulling the smoke through the cabinet requires it to be relatively well sealed, so the form-in-place RTV gasket method was employed on the door following the "gutting and insulating" phase of this project. (Thanks to dward51 for the fantastic pics/writeup of his "MES custom SS model" from which I drew some inspiration).
I also felt more comfortable utilizing two toggle latches on the door in lieu of the single original as supplied from the factory.
There are some signifigant gaps that leak air through the area where the factory temp controller plugs into the element that had to be addressed. Luckily, a bit of 3/8" fiberglass rope stove gasket stuffed in there took care of it.
Of course, I *had* to build a PID controller for it...
"Ports" for the thermocouple and auxilliary temperature probes were made from brass 1/2" x 1-1/8" pipe nipples and conduit locking rings. Same for the smoke inlet port except a longer nipple was used and the diameter of the outboard end was turned-down using a mini-lathe for a better fit inside the vinyl smoke inlet tube.
Joining sleeves for standard 3/4" copper pipe were cut to 0.710" lengths and used as spacers for the nipples between the inner and outer walls of the enclosure. This allows the locking rings to secure each nipple tightly without pulling the enclosure walls together. A spacer was also used on the factory exhaust vent.
A mini-lathe was used to make the aluminum adapter that allows the thermocouple probe to plug right into the ports. I allowed for a couple of different probe locations just in case, although I had to again use the lathe to make the ID of all the nipples match for a precise slip-fit with the probe adapter.
I performed preliminary testing by attaching a Dwyer #460 Air Gauge to the smoke inlet port on the lower left side. I bought this gauge years ago to tune/maintain my fuel oil furnace, and it has been handy for a few other things as well
My 4-gallon air compressor cycles on at 100 psi and off at 130 psi, and only runs for 11-13 seconds every 30 minutes or so (I haven't actually timed it yet). Not too bad at all!
Adjusting the air pressure regulator to near-zero resulted in draft gauge readings down to 0.01" W.C.and lower. During testing I discovered that the readings varied signifigantly as the compressor cycled on and off, depending on whether the pressure was near the 100 psi level or more towards the 130 psi level. I decided to add the second regulator you see in the photos, and I set the compressor's regulator to 50 psi.
The draft gauge reading is now rather steady and and can still be be regulated down to even very low levels (.005"WC).
And for the smoke test...
After tuning the PID and doing a multi-level burn-in, I removed the gauge, hooked up the mailbox pipe and fired-up some pellets in the AMAZN 12" tube and...VIOLA!! A beautiful plume of smoke became visible from the venturi. I played with the regulator setting and watched the plume respond as expected, then opened the door to see good smoke distribution throughout the enclosure.
I was worried that creosote might condense at the outlet of the venturi, but I saw no such evidence of that happening, despite the sub 40-degree ambient temperature. I suspect I could get some condensation once it's loaded up with meat, athough the venturi stayed warm - but not hot not the whole time during testing. Only time will tell.
I am left with the notion that this rig will be very efficient with its use of smoke, so I will endeavour to generate only as much smoke as is needed, and move it through the smoker at a relatively slow rate to allow sufficient condensation/cleaning to occur. I see no reason to generate a excessive amount of smoke only to have to take additional steps to properly clean it before it goes into the smoker.
BTW - missing from the photos are the temporary alum foil plugs in the extra ports that I used during testing. I will be ordering silicone plugs very soon.
Seasoning smoke run will be next, then on to do some real smoking...I can't wait.
Thanks for reading -
John
I've been tinkering with my ideas for this model for some time, and now that it's nearly done - I just couldn't resist throwing out a couple of teaser photos until I have time for my first real smoke with it.
By now everyone probably knows that with the factory setup on the MES 30 Analog, airflow is nearly non-existent and non-adjustable. While it works and does what it was designed to do (more or less) - it's just not how *I* wanted it to work.
As the subject line indicates, this mod "sucks" - that is to say it uses a miniscule amount of compressed air and a homemade venturi to create negative pressure at the factory exhaust port, thus pulling the (hopefully clean) smoke from an external "mailbox mod" and on through the smoker cabinet.
The venturi consists of a 3/8" tee fitting, a 3/8" modified barbed fitting, and a short length of 3/8" brass pipe. The barbed fitting was modified by fitting it with a length of small diameter brass tubing.
Pulling the smoke through the cabinet requires it to be relatively well sealed, so the form-in-place RTV gasket method was employed on the door following the "gutting and insulating" phase of this project. (Thanks to dward51 for the fantastic pics/writeup of his "MES custom SS model" from which I drew some inspiration).
I also felt more comfortable utilizing two toggle latches on the door in lieu of the single original as supplied from the factory.
There are some signifigant gaps that leak air through the area where the factory temp controller plugs into the element that had to be addressed. Luckily, a bit of 3/8" fiberglass rope stove gasket stuffed in there took care of it.
Of course, I *had* to build a PID controller for it...
"Ports" for the thermocouple and auxilliary temperature probes were made from brass 1/2" x 1-1/8" pipe nipples and conduit locking rings. Same for the smoke inlet port except a longer nipple was used and the diameter of the outboard end was turned-down using a mini-lathe for a better fit inside the vinyl smoke inlet tube.
Joining sleeves for standard 3/4" copper pipe were cut to 0.710" lengths and used as spacers for the nipples between the inner and outer walls of the enclosure. This allows the locking rings to secure each nipple tightly without pulling the enclosure walls together. A spacer was also used on the factory exhaust vent.
A mini-lathe was used to make the aluminum adapter that allows the thermocouple probe to plug right into the ports. I allowed for a couple of different probe locations just in case, although I had to again use the lathe to make the ID of all the nipples match for a precise slip-fit with the probe adapter.
I performed preliminary testing by attaching a Dwyer #460 Air Gauge to the smoke inlet port on the lower left side. I bought this gauge years ago to tune/maintain my fuel oil furnace, and it has been handy for a few other things as well
My 4-gallon air compressor cycles on at 100 psi and off at 130 psi, and only runs for 11-13 seconds every 30 minutes or so (I haven't actually timed it yet). Not too bad at all!
Adjusting the air pressure regulator to near-zero resulted in draft gauge readings down to 0.01" W.C.and lower. During testing I discovered that the readings varied signifigantly as the compressor cycled on and off, depending on whether the pressure was near the 100 psi level or more towards the 130 psi level. I decided to add the second regulator you see in the photos, and I set the compressor's regulator to 50 psi.
The draft gauge reading is now rather steady and and can still be be regulated down to even very low levels (.005"WC).
And for the smoke test...
After tuning the PID and doing a multi-level burn-in, I removed the gauge, hooked up the mailbox pipe and fired-up some pellets in the AMAZN 12" tube and...VIOLA!! A beautiful plume of smoke became visible from the venturi. I played with the regulator setting and watched the plume respond as expected, then opened the door to see good smoke distribution throughout the enclosure.
I was worried that creosote might condense at the outlet of the venturi, but I saw no such evidence of that happening, despite the sub 40-degree ambient temperature. I suspect I could get some condensation once it's loaded up with meat, athough the venturi stayed warm - but not hot not the whole time during testing. Only time will tell.
I am left with the notion that this rig will be very efficient with its use of smoke, so I will endeavour to generate only as much smoke as is needed, and move it through the smoker at a relatively slow rate to allow sufficient condensation/cleaning to occur. I see no reason to generate a excessive amount of smoke only to have to take additional steps to properly clean it before it goes into the smoker.
BTW - missing from the photos are the temporary alum foil plugs in the extra ports that I used during testing. I will be ordering silicone plugs very soon.
Seasoning smoke run will be next, then on to do some real smoking...I can't wait.
Thanks for reading -
John
