VCE - Dr Perkins

[Hop Kiln Road]

Have there been any studies using Vapor Compression Evaporation in the maple industry? It would seem to me that this would easier to construct, cheaper and more effective than the current piggybacks. Bruce

[KenWP]

Is that fellow in Vermont not use some kind of steam evaporation . Hard to keep up to you guys and your new ideas.

[DrTimPerkins]

Have there been any studies using Vapor Compression Evaporation in the maple industry? It would seem to me that this would easier to construct, cheaper and more effective than the current piggybacks. Bruce

Cornell Uihlein lab (Lew Staats and others) did quite a bit with VCEs (vapor compression evaporators) back in the late 1970's and through the 1980's I believe. They continued to boil on that evaporator until the late 1990's as I recall. I don't remember whether they took sap all the way to syrup in the unit, or drew off a bit light and then finished in an open-pan evaporator (to allow more flavor/color development). A report was published as a Cornell Bulletin in 1989 I think. You could check with the folks in the Cornell Maple Program for more info.

Advancements in RO technology and use pretty much killed further development. Far simpler just to turn a switch and a couple of valves on an RO to concentrate the sap than to use a VCE.

The technology is used in other industries, including the cane sugar processing industry. The drawbacks are: initial cost is high, maintenance can be extensive, and they are certainly far more complicated than an open pan evaporator. For a very large producer (tens of thousands of taps), a VCE would probably pay for itself in saved energy cost even with RO use.

[Beweller]

HKR, Look on page 94 of the 1982 Producers manual (NE72).

A friend of mine was involved in a test of a Hickman still (VCE) for concentrating sap in, I believe, the early sixties. My memory is that the test was privately financed and no public discosure was ever made.

[Beweller]

The 1958 manual (Hdbk 134, page 19) briefly describes "vacuum evaporation" It is not clear whether the heat source was compressed vapor or a more direct thermal supply.

[Haynes Forest Products]

The laws get really strict when it comes to a closed vessal with steam in it. Its a boiler and the inspection prosess gets complicated. Tea pots and small steam cleaners have a differant set of rules than the kind that can take out the side of the house and 1/2 the family.:o And always remember its the steam you cant see that really hurts

[Hop Kiln Road]

Haynes, yeah I have a 300 hp steam boiler burning No 4 I use for another application and this idea really doesn't involve a pressurized vessel.

But these are my VCE thoughts. As we all know a preheater inside a hood can vapor lock because a reasonable tight hood can produce a little bit of steam pressure and 2 pounds of steam pressure is 218 degrees, thus the vapor lock. 4 pounds of steam pressure is 224 degrees F. If a vapor compression pump intake, which is really just a high pressure fan, were connected to the hood's vent and the vcp's discharge was sent into the sealed underside of a flue pan equiped with a steam trap, sap would boil in the flue pan. I think this unit would be much cheaper and more efficient than the piggyback designs. Imagine, no steam would come out of a sugarhouse, just condensate!

What the wood fired evaporator discussion/new technology is all about is how to apply all the calories in a cord of wood to boil sap.

Bruce

[DrTimPerkins]

I think this unit would be much cheaper and more efficient than the piggyback designs. Imagine, no steam would come out of a sugarhouse, just condensate!

No question that it can be done and has many benefits. Biggest impediment is that it isn't simple or easy (or cheap to develop/adapt the first few units).

[Beweller]

Many years ago I shared space with a guy using a "steam generator". It delivered steam at 600 psi, and was about 4X4X6 feet. I don't recall any posted license or the appearance of an inspector, and within the same building there were business offices. Was it a boiler? I think not.

The danger in boilers is not the presence of steam in a closed container, it is the presence of superheated liquid water.

I never paid much attention to the steam generator, but I suspect it was a forced circulation,once thru heat exchanger. Very little liquid water or steam. Nothing but some pipes.

[Haynes Forest Products]

When I was a Dental Teck we used a steam generator It was called a Steam Master and had a closed boiler with a valve that you pulled a chain to open and it steam cleaned Whatever you put under it. It was used by jewelers and they had to be inspected and in Colo. they have a yearly inspection with a update tag just like a fire ext. They are only 12 x 20 x 24

[KenWP]

There is high pressure and low pressure. I went to school to get my power engineer license. Depends on the size and use for what license you need. The steam generator sounds like the steam jenny we used to thaw pipes. Never needed a license for that as it never made any pressure just steam. Now to heat a high rise is a different thing altogether.