Boiling Sap at 137 Degrees F at 20" hg

[mcmp]

I was up at the D&G open house today. Benoit gave a talk on the new Research/Protype evaporator on display that D&G is developing. The design concept is to lower the air presure and thus reduce the boiling point. The evaporator no longer has a flue pan, but rather a set of stainless steel pipes, roughly 6 inch dia and about 6 feet long where the flue pan would normally sit. The sap is inside these pipes and a vacuum pump draws the interior down to 20" hg. The sap feed is now a pump and the sap out is also pumped out, both controlled by level sensors. The front pan is a conventional cross flow pan. Benoit told us that during testing this past sugar season, running the pipe chambers at 20" hg, sap was boiling at 137 Degrees F with a 1.75 GPH nozzle on the burner. The concept he explained is to reduce the boiling point so it takes less oil to make Syrup, making the evaporator very efficient.

Benoit said that they are still a few years from introduction and much research needs to be done. He said the unit on display operated about equal to a 2 x 8 evap. Looking at the size, I would say it was close to a 3x10 in physical size. He shared with us that the design is in constant research and will go through many changes before a final design is reached.

D&G also has the open house tomorrow, Sat April 28. If you can swing up, you can see this protype, hear the presentation and ask questions. Most Interesting.

Paul ( going back into reading mode

[maple flats]

That must be a big vac pump that can draw 20" vac on a boiling vessel as the steam would produce a huge volumn in CFM to keep the vac. Sounds like it really needs to go back to the drawing board. But, sure sounds like an enviable goal.

[Banjo]

Where is the D&G open house?

thanks, Andrew

[mcmp]

The Vac pump was HUGE !, and I bet LOUD!. It Had two stainless lines from the evaporator pipes to the vac pump. The vac lines were about 4 inch.

D&G USA
164 Yankee Park Road
Fairfax, VT
802-5249625

Just about 3 minutes off I-89

Yankee Park Road is a industrial complex. D&G is in the first building on the right

Paul

[NH Maplemaker]

Guys in the heating /AC trade have known for years that you can boil water at a much lower temp when under a vacum!! A friend of mine who works with AC told me a few years back that if we could create a vac over or in the evaporator that we could boil at a much lower temp and save a lot of money on fuel :oops: I Thought that he had to much to drink :!: But now it apears that he was right :!: 8O He could have been rich today if he would have stayed with that idea :idea: Jim L.

[mcmp]

I questioned/thought about this concept a few years ago. I never figured out how one could draw a vacuum on a hooded Flue Pan. The hooded flue pan would have to be stout so it would not implode. I guess the answer is boil inside stainless pipes. It will be very interesting to see the final market product in a few years.

Paul ( I am going out to fire up my Plasma and Tig ha ha ha

[WESTVIRGINIAMAPLER]

More interesting to see the price. 8O

[220 maple]

During the Highland Maple Festival in March in Virginia two gentlemen apparently AC/Heating repairmen mention to me that water boiled at a lower temp. under vacuum, I replied, What with a supid look on my face I'm sure. I bet we will hear the other equipment dealers say it changes the Ph of the syrup, and whatever other excuse they can come with for not doing it themselves. They are behind on Air Injection will they ever catch up. I tinkered with A.I. in my finishing pan on my Commercial Syrup, I believe if set up perfectly I could bubble all the water out before reaching the boiling point. Whats next?

[Maple Hill Sugarhouse]

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[Russell Lampron]

Kevin-

I thought you were going to keep the V-Rod parked until May 1st. It's still April!

Russ

[Maple Hill Sugarhouse]

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[maplwrks]

Biggest vacuum pump I've ever seen!!!

[Russell Lampron]

Kevin-

I couldn't resist the temptation either I've had my Ultra Classic out a couple of times too. In fact I have some errands to run today and the Harley gets the best gas mileage.

Russ

[Banjo]

I have a question on the vacuum boiling. Although the boiling point is lower, is the heat of vaporization lower too? Otherwise the benefit is only getting back some of the energy required to warm the sap up to boiling, which is about 20% of the vaporization energy (and can be got for "free" with a pre-heater).

I'm sure I'm missing something.

cheers, Andrew

[WESTVIRGINIAMAPLER]

In my opinion, a preheater only gives you about 10% increased efficiency.

If this works so good, why not go with a good tight steam hood and put a good fan in the stack that can stand up to the vapor and such the steam right out of the hood faster than it can evaporator. You would lose the preheating ability, but I would think it would still increase gph. I have always thought this could be done, but I won't likely experiment with it. :?

[Rob Harvey]

I do not think it will work Brandon, a fan only will move air when it has air coming in to replace what it is moving. In other words when you get to the point where you have neg. pressure in the hood, the fan wont move air. Rob

[mcmp]

Asumming you could totally seal the hood to the pan, and seal all openings in the hood, a fan would lower the internal pressure just a little tad. Who know how much with out real lab testing. Sure, by lowering the internal pressure anything below atmospheric, would drop the boil point. But without a large vacuum pump your gain might be in tenth's of a degree in boil temp (just guessing).

If it was as easy as adding a fan and tight hood, D&G would not have built that expensive research evap. And others would have already done it. As with any new invention, lots of research and testing must be done before it becomes a market product. Look at air travel in the begining and then now, early navigation compared to today, its all an evolution process. This appears to be the ground floor.

Unless..............who knows what some person may be designing and working on today in his shop that will eventually get a patent ? It would not be the first time an individual, in his own shop, created or improved on a machine.

Its sort of fun to think about the concept, what is going on right now, and then see how long before something like this is on the market.

Paul

[WESTVIRGINIAMAPLER]

I wasn't necessarily referring to lowering the internal pressure but pulling the steam out quickly. In my opinion, the faster the steam is getting away from the boiling surface, the lower the humidity and the faster it would evaporate. One of the problems with hoods is that they trap so much steam inside and have to increase the pressure some on the boiling liquid.

Just a theory. :?

[brookledge]

Another thing that you could do is put in a heat exchanger off the big vacuum pump that they are using. You could heat the sap and cool the vacuum pump at the same time.
Keith