This is my vacuum releaser. I built it from 12" PVC watermain that I pulled out of the garbage pile at a local construction company, aluminum that I bought at my local metal supply company, lexan that I bought and had machined at a local plastic supply company, and blumbing that I bought on Ebay, Amazon, AliExpress, and at local hardware stores. The large white pipe and the clear check valves are from CDL.
I spent the day today cleaning everything, replacing a couple of o-rings, and putting the machine back together. I had a big vacuum leak that it took me a while to find but I eventually managed to get the main releaser chamber down to 26.5 inhg.
The vacuum releaser is like an airlock. I draw the hole system down to a moderate vacuum which pulls the sap in from the trees. Once the upper tank is full I have to get the sap out somehow. If I just open a valve the vacuum will suck air in but the sap won’t run out. The vacuum releaser closes a valve to the vacuum pump and opens a valve to the air. That releases the vacuum. When the air rushes it it closes a check valve that keeps all the tubing in the woods under vacuum then the weight of the sap pushes another check valve open and the sap runs into the lower tank. When the sap has all run out the valves reverse, a vacuum is drawn in the top chamber, and the sap starts coming in from the trees again.
The idea is to get the sap out of the vacuum without letting all the vacuum all the way out to the trees go. It takes a while to get the whole system back down to vacuum so I preserve as much of it as I can.
Ohhhh, so it’s part of the sap collection process. That makes sense that you gotta get the sap out of the vacuum side as it fills up, without pressurizing the whole system
Yup. Exactly. It releases about 30 litres of sap at a time.