Teuchtar
04-02-2013, 09:18 PM
A really inexpensive performance enhancement can be economically made and works in principle like the Piggyback or Steamaway.
I have a rake of 4 copper tubes pierced 1/8" at 3 inch intervals, 48 in long. This assembly of four parallel tubes is a sparger, and connected to a fuji ring blower (same as Gast ring blower). This is immersed in my round-bottom tank which serves as the evaporator header tank. The blower bubbles fresh air into the feed tank.
Then from the drain, I run the concentrated sap over to a procon pump. This pumps the cold concentrate into a 100 foot coil of copper tucked into the steam hood. With the evaporator running, the sap re-emerges from the coil heated by the steam, and is dumped back into the header tank to help with the heat of evaporation by the blower.
This rig gets me an additional 65,000 btu/hr of heat recovery, enough to evaporate an additional 8 gph, and plenty of heat to raise the feed temperature to the float box up to 180 degrees for another roughly 2 gph on the main evaporator.
The real piggyback/steamaway is prohibitively costly for a small rig. But you might find this a fun project to build, and the components are easy to plumb.
Compare the cost: Pump ($150), Copper coil ($200), Tank ($200), Hood ($900 ). I already had the pump, tank and hood, so cost was quite irresistible compared to the commercial devices.
Future tweakings when time permits should recover more of that waste steam and put it to productive work. Test data available on request.
A second homemade enhancement is the auto draw-off. I got mine working this weekend. Like the similar models, I have an auber instruments PID controller, running an Erie zone valve, with an RTD to monitor temps. This is a really easy project to build. It takes away all the fussing of hydrometer, and manual drawoff. Way too much distraction. The only catch is that you have to keep an eye on the bucket, and have an empty one ready to go. (learned the hard way !)
Third enhancement is a K-thermocouple in the exhaust stack. I run a 10 inch stack on my 2x6 rig, so don't need auf. I monitor the temp to keep it 650 to 750. Nominally firing every 5 mins our so keeps it running on peak output. THe auto drawoff allows me to focus all my attention on the firing, and occaisionally monitor tank levels. Temps under 500 indicate firing neglect and productivity loss. Temp over 750 just wastes the flames as they project right beyond the flues into the stack.
With this setup, and my RO, I was able to bring my incoming sap to 16 brix at the float box, and overall made 45 gallons in under six-hour boil.
I have a rake of 4 copper tubes pierced 1/8" at 3 inch intervals, 48 in long. This assembly of four parallel tubes is a sparger, and connected to a fuji ring blower (same as Gast ring blower). This is immersed in my round-bottom tank which serves as the evaporator header tank. The blower bubbles fresh air into the feed tank.
Then from the drain, I run the concentrated sap over to a procon pump. This pumps the cold concentrate into a 100 foot coil of copper tucked into the steam hood. With the evaporator running, the sap re-emerges from the coil heated by the steam, and is dumped back into the header tank to help with the heat of evaporation by the blower.
This rig gets me an additional 65,000 btu/hr of heat recovery, enough to evaporate an additional 8 gph, and plenty of heat to raise the feed temperature to the float box up to 180 degrees for another roughly 2 gph on the main evaporator.
The real piggyback/steamaway is prohibitively costly for a small rig. But you might find this a fun project to build, and the components are easy to plumb.
Compare the cost: Pump ($150), Copper coil ($200), Tank ($200), Hood ($900 ). I already had the pump, tank and hood, so cost was quite irresistible compared to the commercial devices.
Future tweakings when time permits should recover more of that waste steam and put it to productive work. Test data available on request.
A second homemade enhancement is the auto draw-off. I got mine working this weekend. Like the similar models, I have an auber instruments PID controller, running an Erie zone valve, with an RTD to monitor temps. This is a really easy project to build. It takes away all the fussing of hydrometer, and manual drawoff. Way too much distraction. The only catch is that you have to keep an eye on the bucket, and have an empty one ready to go. (learned the hard way !)
Third enhancement is a K-thermocouple in the exhaust stack. I run a 10 inch stack on my 2x6 rig, so don't need auf. I monitor the temp to keep it 650 to 750. Nominally firing every 5 mins our so keeps it running on peak output. THe auto drawoff allows me to focus all my attention on the firing, and occaisionally monitor tank levels. Temps under 500 indicate firing neglect and productivity loss. Temp over 750 just wastes the flames as they project right beyond the flues into the stack.
With this setup, and my RO, I was able to bring my incoming sap to 16 brix at the float box, and overall made 45 gallons in under six-hour boil.