Pump instead of head tank.

As I’m building my setup here I got another hairbrained idea. Anybody plumb the outlet of their Shurflo pump directly to the evaporator feed, no head tank? In my case 4 - 3/16” sap lines would feed a Shurflo inlet and the outlet would pump either to a storage tank or to the heat exchanger inlet on the copper pipe around my chimney. Also a throttling valve somewhere to control the flow into my pans. This could eliminate my head tank and issues I have with that.

If I did this I would only have 1/2 gpm flow from the pump at times. Not sure if that would slow the pump down and lower vacuum in the lines? Anyone else try this? Thanks.

You need to ask yourself - what can go wrong and what am I risking? One scenario is that you power supply cuts out and the pump stops delivering sap to the evaporator. If you add all the contingency measures for all the possibilities then you'll probably determine that a head tank isn't a bad idea.

it could be done but it's risky. especially with a small pump i'd worry about possible vapor lock/unpriming the pump from the preheater as it creates back pressure, plus the power issues below. much easier to have a small head tank and put a float in it, use the pump to keep the head tank full.

I have used a Super Transfer Variable Speed Self Priming Transfer Pump for the past 10 years. I added an extra in-line screen filter (pump is available at morebeer.com). I keep an eye on it and adjust the flow when needed (I also have a low level sap alarm). My 3x10 arch has a preheater and boils at 110/hour. I keep a spare pump on hand just in case. These pumps have lasted for about 5 years for me.

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Originally Posted by FL Maple

I have used a Super Transfer Variable Speed Self Priming Transfer Pump for the past 10 years. I added an extra in-line screen filter (pump is available at morebeer.com). I keep an eye on it and adjust the flow when needed (I also have a low level sap alarm). My 3x10 arch has a preheater and boils at 110/hour. I keep a spare pump on hand just in case. These pumps have lasted for about 5 years for me.

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I assume that you have a raw sap tank that you pump from to serve as a reserve. It sounds like in the event of a pump failure, you bypass the failed pump with a backup and hopefully without significant delay. Then, if necessary, you could flood the evaporator using the reserve capacity to stop an overheating condition. As we all know, once things reach that critical condition it can't easily be tempered down.

I'm not sure I understand the situation the poster inquired about but it sounds like he's asking about using his shurflo pump to draw sap directly from the "sap lines" to the evaporator. I would consider this much riskier since the reserve capacity is more limited and might not be available at the rate needed to temper the system in an emergency. It also risks a failure in the lines such as a break from a fitting failure or tree falling on the line.

Other concerns

- The typical sap run lasts from a few hours to a few days. So if you're taking the sap in real time it means you work to the schedule of the trees and not for you're own convenience.

- You'd need to size the number of taps to the evaporation rate of you rig with a significant buffer which means wasted sap. So you'd collect that excess sap in an overflow tank that could instead serve as your head tank.

Ken

Ken

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Originally Posted by TapTapTap

- You'd need to size the number of taps to the evaporation rate of you rig with a significant buffer which means wasted sap. So you'd collect that excess sap in an overflow tank that could instead serve as your head tank.

Ken


Ken

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I would agree with that. On that note. If anyone out there can figure out how to get their trees to run day upon day to the rate of the evaporator (RO then Evap) and only on my schedule let me know and my tanks will be on the market the next day haha.

A few things to consider:

1. Trees do not flow consistently and therefore your flow of sap is not consistently feeding your evaporator. If your rig is wood fired you could easily run into a problem.

2. If you are feeding a float will the pressure from the pump overwhelm the capacity of the float?

3. You are removing a safety parameter/insurance policy by not running a head tank, even a 15 gallon barrel will offer a small buffer to respond to a interruption in the flow of sap.

Your right, its a hairbrained idea! :) yeah you could probably do it and it may work a while but it will end in a burnt pan.

Just put in a small head tank so you have some buffer.

Thanks for the reply’s.

I know someone who plans to use an air powered double diaphragm pump to pump from a tank on the ground to the float box on the evaporator. Adjusting the air pressure to the pump will allow the pump to run when needed and stall when not needed. I'm don't trust that plan for the reasons already mentioned here.

Gravity never fails...never.

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Originally Posted by Michael Greer

Gravity never fails...never.

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Once again, hard to escape the laws of physics...no matter how much we may try.