I stand Corrected because not one post mentioned shutting down the flow after higher vacuum levels were achieved.
I stand Corrected because not one post mentioned shutting down the flow after higher vacuum levels were achieved.
Now that brings up another dilemma. If you have an over sized pump for the capabilities of the tubing system you are building in the NOT ENOUGH LIQUID to run the system and you will always have cavitation lowering your vacuum levels...................Right??
Not really the case
A diaphragm pump will have an optimum flow rate for generating vacuum, where the fresh sap flow rate is far below the full open flow rating of the pump. Open flow rate is 3 or 3.5 gpm on a shurflo, or 180 gallons per hour. Nobody is going to have that many taps on a little pump like that, so we will always be operating well below the open flow rate. I haven't done detailed tests, but I have about 50 taps on my shurflo, and on a great run I suppose it might flow 100 gallons over a 10 hour period, or less than 0.2 gpm. Thats plenty of flow for keeping the diaphragm wet and working well. You can see that a little recirculation throttled in could maybe double or triple that flow through the pump and still be well below the open flow rating. So even if you leave the recirculating line open on good days, it still works ok, and is there to fill in if the trees slow down.
There will always be some bubbles in the lines, always some air going through the pump, but the recirculation line keeps something in the pump when things slow down.
John
2x8 Smokylake drop flue with AOF/ AUF
180 taps on sacks
75 on 3/16 tubing with shurflo
Eden Prairie, Minnesota
No offense, but my original question is still unanswered. Can I just tap the out going line on the pump side or should I run a line back from my collection tank. I really can't see any difference.
2017- Started small-made 7 gallons. Long days & few nights on a 1x2 and turkey fryer.
2018- Bought a 2x4 and built a small scale RO. 21 gallons.
2019- moved up to 100 gph procon for my home built RO. Built a steamhood. About 220 taps and 21 gallons again.
2020- 140 procon on the R0. Added a new mainline at my in laws. 330 taps for 24 gallons, sold excess sap.
Got distracted I guess!Originally Posted by Mark B
I have multiple suction lines and drop one into the tank for recirculating, with a needle valve to limit flow. If you pull off your outlet line you risk not having a steady Source in low flow situations, which is when you want to assure a wet pump.
John
2x8 Smokylake drop flue with AOF/ AUF
180 taps on sacks
75 on 3/16 tubing with shurflo
Eden Prairie, Minnesota
which shurflo
which shurflo? I am using a NorthStar NSQ Series 12V On-Demand Diaphragm Pump - 3 GPM @ 60 PSI. It works well but I only achieve 12" on 100 taps even with a recirculating line. Brand new diaphragms, same as last season. Are the shurflo pumps that much better?
I use a 4008, 12V 55psi and 3.0 GPM I can pull 18-20" H2O. After I've walked the lines a few times and have everything "leak free".
Smoky Lake 2x8 Raised Flue
Mason Arch
5 Buckets
300 Gravity
120 High Shurflo vac
7" Wes Fab Filter Press
Mason Finisher
Mason Water-Jacketed Canner
Do you think there is that much difference between the two pumps
So BAP says he gets 20-24" on 100 taps. really? Cause I want some of that.
Well I guess the only way to really know is to buy the shurflo 4008, so done!! It will be here Wed. I will keep you posted. I did note some differences, at least in the written description. Shurflo does not say "ON Demand" but there is a "check valve" listed on the shurflo. Who knows if the other has same characteristics. Priming distance is less
Posting Permissions
Reply With Quote
