Bernard air injector for sap ladders

[Brent]

Anyone out there seen one of these in use ?

One of our local dealers has posted this picture of an air injector for a sap ladder with the following comments

http://www.duffyslanemaple.ca/AIRINJ.jpg

"Another genuine BERNARD innovation! This ingenious device when used with a check valve, periodically allows a burst of air into the line just ahead of a sap latter (not included) allowing the sap to travel up the ladder quickly and easily. Fully adjustable for air volume and opening/closing frequency. Complete with check valve"

It looks to me like it uses the same kind of cylinder/valve as the Bernard mechanical releaser to release a gulp of air into the tube to push the sap up the ladder tubes.

They're offering it at $ 279, Canadian $

[Russell Lampron]

It won't pulsate like that one does but a ball valve slightly cracked introduces air into your ladder for alot less money. I don't have the pieces to give it a try but I think that a milking machine pulsator could be made to do the same thing.

[ennismaple]

Brent - They will lose more vacuum from top to bottom than a standard "spider" ladder because of the air.

I personally don't think they are necessary - my 4 sap ladders all work fine without them but I haven't used one so I could be wrong. From watching my ladders work all air does is bubble through the sap and then the sap falls back down. To me it looks like the sap builds up to the top of the ladder and is "grabbed" by the vacuum at the top to pull the rest of the sap up.

[Brent]

I think the idea behind this is to have the device closed so the vacuum sucks some sap up into the vertical tubes ... maybe a foot or so, then like a releaser, it opens to let normal air pressure in for a second or two to make a big bubble that will push the sap up ... maybe more efficiently than a slow stream of contiuous bubbles that don't move very fast. The slow stream letting more sap fall around the bubbles than the fast moving bubble that this will create.
I notice they have a check vavle to stop the "big bubble" from going back into the mainline and reducing vacuum there.

I think it will lift more sap for a given amount of vacuum loss than a stream of little bubbles. I think they may lift higher in a single lift too.

That said, I have never seen one and not got any comments back from the dealer yet. Nothing on the LaPierre/Bernard web site about them at all.

[maplwrks]

They work pretty slick. Russ hit it on the head--they are nothing more than a milking pulsator, only this one is adjustable. I feel that nicking one of the stars at the ladder, to introduce a little air is just as good, and CHEAPER!!

[Brent]

What's cheap and what's expensive ?

Postings here say each inch of vacuum is worth 5% more sap flow.

How much do you lose on a ladder that is continuously bleeding small bubbles ?
I've don't recall anyone saying what a traditional spider ladder costs in cfm and vacuum. Someone should know.

Sap ladder and tight system don't seem compatible.

How much does this rig lose with its ( my phrase ) big bubble that fires periodically? I'm only guessing but I think this will move more sap up with less vacuum loss, fewer cfm and vacuum loss could be real expensive.

[Brent]

They work pretty slick. Russ hit it on the head--they are nothing more than a milking pulsator, only this one is adjustable. I feel that nicking one of the stars at the ladder, to introduce a little air is just as good, and CHEAPER!!


Mike, does this mean that you've seen and/or used one of the Bernard devices or are you saying the milk pulser works slick.

[maplemas]

I’ve searched and read the 400+ sap ladder topics and can’t find anything about these injectors . My question is how well do these work when temps are 32-35 ? I’ve used ladders for years but I find the micro leak I put in to get them to work causes them to freeze at these temperatures. Also what are you finding for vacuum loss after the ladder when using these ?

[TapTapTap]

I really don't think I have much unused sap backed up behind my ladders so what's the point? It likely looks like more is happening with the air injection but I don't think it does much more.

BTW each foot of ladder height uses about 1 inch of vacuum on the upstream side. So if you're getting 28" in your dryline then you should be around 18" upstream if you're lifting 10 ft.