CFM loss and lift

[CrossBroMaple]

Anyone have a chart that shows cfm loss as its related to ladder lifts?

[maple flats]

That might be covered in Steve Child's Tubing Handbook, available thru Cornell or most larger maple equipment dealers. I don't see much in practice, I have 26-27" vacuum of unknown CFM (old BB4 piston pump), at the end of my mainlines, I get 25" after 2 sap ladders. Both mainlines are 1", one is about 750' long and the other is only about 600' long and as stated both have 2 sap ladders between 7' and 10' lift on the longer one and a 5' lift and a 12' lift on the 600' main.

[johnallin]

Anyone have a chart that shows cfm loss as its related to ladder lifts?

Matt, Fred over at Richards Maple may have that info..just put a CDL sap lifter in over here, working like magic- so far.

[CrossBroMaple]

I just installed two 10 foot ladders using 1/2 in riser and do have vacuum after the lifts just was curious about how much cfm loss occurs. I also am utilizing an old sp22 dairy vacuum pump with unknown cfm

[maple flats]

I think the SP22 and the BB4 are quite similar in size.
On my BB4 I have a 1800 RPM electric motor with a 4" drive pulley, I think the driven pulley is 10", if that's correct, the pump is turning at 720 rpm. On my system I get 26-27" vacuum at the releaser and at the far end of the mains, after 2 sap ladders on each I get 24" on one and 25" on the other. One has about 220 taps, the other about 150 taps, but when done adding new this week the two combined will be somewhere between 400 and 450 taps total.
My thinking is that the vacuum at the far ends is more important than the CFM, as long as the ladders work properly. For this year my ladders are all on star fittings, my other woods which I've now retired had 3/4" risers, 2 each ladder. I'm thinking for next year I will change the ladders to 2 lift lines each of 1/2".

[CrossBroMaple]

Thanks everyone,
I do have vacuum after both lifts but curious about cfm for future tap expansion and new vac pump possibilities. as I read through the cornell tubing book it didn't have a definite answer in regards to lift systems.