Thursday, September 27, 2012

A well pump idea from Hans



 
I was looking at third-world solutions (PDF's) for well-pumps to get ideas for a manual pump that could be lowered into my well-casing in the event of a grid-down SHTF scenario.  I decided to play a bit in the shop and prototype 'my' version of a lift-pump.
 
The bottom disk on the lift rod is the 'flap valve' made of a circle of neoprene rubber (valve and guide - 2).  I added a second disk to minimize binding of the flap valve when the lift rod is operated.  The brass check-valve at the bottom is the only style available yesterday at Home Depot.  I would have preferred an in-line style check-valve that could be mounted inside the 1.5 in PVC cylinder.  A piece of hobby-shop brass tube is slipped over the threaded rod and secured with nuts to provide a smooth surface and minimize wear at the top cap.  I would use unthreaded rod in a 'production' pump.
 
I noticed the diameters of the valve and guide disks have to be sized for the specific PVC chosen for the pump cylinder.  There is enough variation in the internal diameter of several scrap pieces of 1.5 inch Type 1 Schedule 40 PVC that the disks are loose in some and won't fit others.  This was the only "critical" parts dimension.  The neoprene circle was trimmed "proud" of the disk with scissors. 
 
Several web sites described similar hand operated lift pumps that could be used at depths down to 100 ft.  For short depth of my well (30- 40 ft ... water at 20 ft) the lift rod could be 1/4-20 threaded rod.  For deeper wells I would use lengths of commercially available fiberglass lift rod. 
 
This prototype is clearly a throw-away experiment, but it operates with low friction and really does a great job of pumping out my rain buckets !  With a few minor design changes to the lower check-valve, riser pipe and addition of lever style pump handle, I could envision lowering 30 ft of this into my well-casing. 
 

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