Viot vacuum pump, opinions?

[Tweegs]

I’m looking at a pump here and wanted to get a few opinions on it before shelling out the cash.

Here are the specs:
Viot model VPDS12
Single stage rotary vane, 12 CFM
3/4 HP
Continuous duty
40 micron rating (29.93” Hg)

The claim of 29.93” Hg sends up the first red flag. They don’t specify the conditions for achieving that kind of vacuum.

On the other hand, looking at pumps from my sugaring supply house, an 8 cfm ¾ hp pump will handle 1000 taps (@ 20”). By that measure, the Viot pump should easily handle my bush, but let’s talk about that a second…

I have about 180 taps that would be on vacuum in the main bush, on about 1000 feet total of main line. One ladder would be necessary, about 8 feet, to get to 40 of those taps. Those 40 taps will be on about 300 feet of main. Because I won’t have electricity at the shack, the vacuum pump will be located in a barn and require 800 feet of dry line to get to the releaser. Only the last 100 feet of wet line is 1”, the rest is ¾. The dry line will also be ¾ (for the moment, at least).

I have another 30 taps in a stand of silvers that I’m going to leave on gravity until I can figure out a feasible way to get them on vacuum. The barn is on high ground between the main bush and that stand of silvers. It would take a 15 foot ladder to combine the two, along with another 600 feet of main, and a better understanding of how a wet/dry line would work in this situation.

Given my set-up, is this enough pump?
Does anyone have experience with this brand of pump?
Is this type of pump totally wrong for this application?
Have a look at it here: http://www.viot.us/showproduct.php?model=VPDS12&sw=0

Appreciate any input you folks have.

[tuckermtn]

I couldn't find it on the website but I would want to know what the cfm is at various inches of Hg. But realistically you are only going to need 2 or 3 cfm for the set up you describe. Most HVAC pumps are designed for short evacuation duties- not sure if they will stand up to the sometimes 24/7 of the sugaring season.

[Tweegs]

I wrote the manufacturer trying to get the CFM over vacuum range answered. No reply to date. If they aren’t interested in helping, I’m not interested in buying.

2-3 CFM? I thought I’d need more, but that’s just peachy. I hear some folks use the Gast pumps for small operations like mine. I’ll have a look at those.

[maple flats]

2-3 CFM, if it is a perfectly tight system, which few are. Also add 2-3 CFM for sap ladder, maybe more. I'm not clear on your pump specs. The 40 micron is confusing. Filters are rated in Microns, a micron being a particle size. If they are saying you can get up to 40 micron particles thru at up to 29"+, should be good. I also would be concerned if you requested a performance curve a few days ago and got no answer yet. I would call the manufacturer and ask for tech support. If that fails I'd buy something else.

[Tweegs]

Did some digging around and found this as it relates to microns:

Atmospheric pressure is about 29.92 inch Hg. Any pressure below 29.9 in Hg is considered to be under vacuum. So, absolute vacuum is 0 in Hg, or 29.92 in Hg vacuum! At very low pressure under vacuum, micron is used. One micron is defined as 1 micrometer Hg in absolute pressure. One inch Hg has about 25,400 microns in pressure. 25 micron will be about 29.92 in Hg vacuum! Deep vacuum pumps are rated by their vacuum levels they can achieve in microns. So, the lower the micron rating, better is the pump, deeper the vacuum it can reach.

Also found contact person and shot him an e-mail. We’ll see if this produces any results.

[Tweegs]

How ‘bout that…a rather quick reply. Though not the one I really wanted, at least he was honest.

My interpretation of the somewhat broken English is that even though it is rated for “continuous” duty, continuous duty does not mean 10 hours a day, every day, for a month.
He suggested that it wouldn’t hold up to the demands we sugar makers would place on it.

So the hunt continues…