The Poorer Man's Diaphragm Pump Vacuum System

[Cedar Eater]

I am testing a smaller cheaper diaphragm pump for use as a mechanical vacuum pump on a 3/16" sapline that is nearly level and has 28 taps. It is a two chambered 12 VDC pump with 3/8" hose barb fittings. It's too cold here to install it yet, but the forecast for late this week or early next looks good. I bought two pumps, one from eBay for around $15 and a Favson from Amazon for around $26. I discovered that they are identical in all observable respects except their labels and packaging, so I decided to only test the cheaper one. This is a pic of the two pumps next to a Shurflo 4008, which is a four chambered pump.

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Here is a pic of the test setup.

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The pump initially only drew a vacuum of 5" Hg, but as soon as it got a little water into it, the vacuum jumped to 17". When I pinched down on the valve that will become the bypass line, the vacuum jumped to 25", which is better than I expected. It's going to be interesting to see how it performs in service. If the motor and pump last the rest of the season I'll be happy if they last through next season, I'll be really impressed. If either fails, I'll report that. Unlike the Shurflo, the motor is not enclosed, so I will be enclosing it to protect it from rain and snow.

[mspina14]

Neat.

Let us know how it works out.

Mark

[littleTapper]

Cool! Looking forward to some data. I've got a "remote" 6 taps at my mother-in-law's and 10 box elder taps that a full-blown 4008 setup would be total overkill. Really curious how long it'll run on a deep cycle battery.

[Cedar Eater]

I got a pair of the smallest cheapest deep cycle batteries I could find, in keeping with the cheaper-is-better approach to the experiment. $60/ea. I do plan to report on how it goes. I've heard these pumps fail quickly without a strainer up stream, so I found a cheaper-than-Shurflow 50 micron strainer that also has 3/8" hose barb fittings.

[Ghs57]

This should be very interesting.

[Biz]

I just ordered the same Favson pump yesterday to experiment with. Might not get to do much this year with it, but I will have 4 short 3/16" lines next year that are too far apart use one pump on, so I could have 4 pumps out there, 20-40 taps each. I will still use my controller unit but maybe scaled down. It will be a fun experiment.

Dave

[wmick]

Thanks for the explanation, Cedar Eater... Makes perfect sense...
I have another question though... I'm thinking about a way to allow the sap to bypass the pump and work on natural gravity/vacuum, in a case where the battery goes dead or pump quits... Do you think your "bypass" line would accommodate enough volume for this on 40 or 50 taps? I was also thinking maybe about some sort of 2nd bypass line with a weak check-valve in it.. (that the pump would pull closed under vacuum, but it could fall open if vacuum disappears.
Any ideas??

PS - another thought... Will the trees not draw your sap back though your bypass... if you are not there to disconnect things when the temp starts going down each evening??....

[Cedar Eater]

Thanks for the explanation, Cedar Eater... Makes perfect sense...
I have another question though... I'm thinking about a way to allow the sap to bypass the pump and work on natural gravity/vacuum, in a case where the battery goes dead or pump quits... Do you think your "bypass" line would accommodate enough volume for this on 40 or 50 taps? I was also thinking maybe about some sort of 2nd bypass line with a weak check-valve in it.. (that the pump would pull closed under vacuum, but it could fall open if vacuum disappears.
Any ideas??

PS - another thought... Will the trees not draw your sap back though your bypass... if you are not there to disconnect things when the temp starts going down each evening??....

There's a very smart controller that Biz will be marketing called the Super Sap Sucker that opens a valve to allow gravity flow when the pump gets shut off due to cold or low battery. I don't think the bypass will accommodate much flow with natural gravity. I would not turn the pump off until the temps drop to at least -1^oC. By that time, the frozen tubing should be preventing either natural gravity flow or reverse flow. Keep in mind that the goal here is a cheap system for fewer taps and lower amounts of flow than you would put through a Shurflo 2088 or 4008. You won't lose much if you lose the whole system and you won't lose much sap if you're not running when you would want to be.

[wmick]

I started installing some 3/16" line for the first time late yesterday... (definitely takes more time to install than buckets) I was impressed to see that there was actually some sap running, as it was still below zero.. These trees get some decent sun.. Installed 25 taps .... 13 on one line and 12 on another, back to a single 40 gal drum... I don't have the pump ready yet but the trees were pushing sap pretty good, even with little to no fall... It was interesting to see the sap reverse in the lines, when the sun went down... Don't get to witness that with buckets. Looking forward to see what happens over the next few days.

[sugarsand]

Where did you find the cheaper strainer filters? We started using these ebay cheapies last year, still running strong this year. The pumps are all 4L/m and draw about 1.1 amps an hr, which if I understand it right, a 12amh battery should last10 - 11 hours. These pumps will generate more sap at a cheap cost.