Sunday, June 9, 2013

A hardware store DIY deep well hand pump shopping trip

Based on three videos at Youtube (Peters, agua:yaku, and a "prepper"), I decide to go to the hardware store and see what kind of a hand pump I could come up with quickly and easily with ease and speed of assembly being more important than cost. I was surprised at how quickly I ended up with a pump lying in front of me on the floor of the store.
The only cheats of my dry run of a pump fabrication were the actual pipe connections, the foam seal creation (from a flip-flop sandal sole), the removal by melting, grinding, or shaving of the ridges on the 3/4" fittings near the foam seal, and the drilling of several dozen holes into the 3/4 pipe above the piston seal.

I decided to save a lot of time and creativity by using pre-fab check valves instead of making my own.  I think that was a good decision.  The only check valves I could find were bloated PVC versions.  So the only way I could fit one inside the well casing was to make it 2" OD in the area of the check valve (the bottom of the pump).  As a result, the pump looks like a 1 1/2" pipe that swells to 2" then shrinks to 1" before the bottom 1" check valve.  If size isn't an issue, the entire casing could probably be increased to 2" from 1 1/2".

The cost of the fittings as shown is $32.24.  The pipe cost is $0.228/ft for 3/4", $0.367/ft for 1", $0.522 per foot for 1 1/2", and $0.0772/ft for 2" (pipe costs in the photos have some mistakes), or about $75 for pipe a 100 foot deep well.  The total pump cost is about $110 for a 100-foot (30 meter) deep well.

Here's the pump.  I am arranging it in vertical order, and I suggest you spend most time examining the bottom.

Photo 4 

Photo 4 shows the above-ground part of the pump.  It's easy to understand.  From top to bottom there are:
-3/4" tee with horizontal pieces of 3/4" PVC (imaginary)  for a handle.
-3/4" pipe piston rod shaft.  It goes up and down.
-1/2" x 1" reducer that allows 3/4" pipe to slide up and down
-1 1/2" tee to direct water out. This is minimal, and you would want to add more fittings and pipe to connect as needed.
-1/1/2" pipe pump casing.  It doesn't move.  It carries water.

The cost of the fittings in this photo is $4.22

Photo 3

Photo 3 is an amendment to Photo 2, and I apologize for the confusion.  The purpose of this photo is to show the 3/4" threaded fittings that go above the 3/4" check valve and (not shown) above the 2" x 1 1/2" reducer.  The threaded fittins hold a foam donut piston seal cut from a flip-flop sandal sole so it can slide inside the 1/1/2" pipe.  The agua:yaku video shows how this seal can be held by threaded fittings.

A key innovation of this pump from a hydraulic engineering perspective is that the entire length of the 3/4" pipe above the seal and under ground is perforated with around 20 to 50 1/4" holes to let water exit upward from the downward moving pipe on the down stroke.  To reduce hydraulic losses and direct water upward as it exits the 3/4" pipe, these holes are drilled at an angle downward into the center of the pipe, and burs are removed as much as feasible.   I recommend drilling holes every 6" in two diametrically opposite lines.

The 3/4" fittings have ridges that must be melted and shaved away so the fittings fit inside the 1 1/2" pipe.  Water doesn't flow through this space (that's why there's a seal here), so a close fit is fine, as long as they don't rub.

From top to bottom the parts at the seal fittings are:
-3/4" pipe (hidden) that leads to a handle at its top and has several dozen 1/4" holes for the upward exit of water on the down stroke.
-3/4" threaded male adapter that compresses the foam seal below it
-1 1/2" diameter foam seal trimmed to slide without leakage inside the 1 1/2" pump casing (omitted for clarity)
-3/4" threaded male coupling
-3/4" threaded male adapter that completes the threaded assembly and

The cost of the 3/4" fittings is $1.67.  Removing their ridges is the most difficult part of this fabrication.  Making the holes in the 3/4" pipe requires a drill.

Photo 2

Photo 2 shows the 3/4" check valve that goes up and down inside a couple foot long 2" section of pipe.  The length of the 2" pipe minus the length of the 3/4" check valve determines the final length of the pump stroke, which I assume should be about 2 or 3 feet.  This pump will pump about 0.092 gallons per foot of up stroke, so a 2-foot stroke will yield about 3 cups or 3/4 liter, and it will take about 108 2-foot strokes to pump ten gallons of water.  For flexibility, it's probably wise to allow extra stroke length.

There is really no upper limitation on the length of the 2" pipe section.  In fact the entire outer casing can be made of 2" pipe instead of 1 1/2", with the only disadvantages being increased bulk and lifting force (because the seal in photo 3 would be in a 2" pipe instead of a 1 1/2" pipe).  The advantage would be that the pump would lift 0.16 gallons per foot of stroke, nearly double the output of the 1 1/2" seal.

From top to bottom, the parts around the 3/4" check valve are:
-1 1/2" pipe casing leading from the surface
-2" x 1 1/2" reducer to make a larger section for the check valve
-2" coupler
-2" pipe pump casing about 3 feet long (omitted for clarity)
-3/4" pipe shaft inside the casing leading down from the foam seal.  This length of pipe is NOT perforated.  If the entire well casing is increased to 2", this pipe can be very short to put the seal immediately above the 3/4" check valve.
-3/4" check valve directing flow upward at the bottom end of the 3/4" pipe shaft.

The cost of the fittings in this photo is $10.32

Photo 1

Photo 1 is the section of the pump below the movable shaft and check valve.  This is the foot valve section.  The only purpose of all these parts is to attach the 1" check valve at the bottom of the shaft.

I haven't included a sand screen below the 1" check valve (the foot valve).  A cage of some type could be added and wrapped with a filter fabric bag.

From top to bottom, the parts at the bottom of the well shaft are:
-2" coupler (shown in photo 2)
-2" x 1 1/2" reducer
-stub of 1 1/2" pipe (omitted)
-1 1/2" coupler
-1 1/2" x 1" reducer
-stub of 1" pipe (omitted)
-1" check valve

The cost of the fittings described is $16.03.


Anonymous said...

U can eliminate several fittings accomodating the check valves by using a 3/4 male fitting, neopreme marble & O ring as a seal (see "How to make a simple seal" on Youtube )
Thanks for the proper
labeling & layout in ur vid. Very good.

Dan Roy said...

Good vid, well labeled & explained, u can save some fittings if u veiw "How to make a one way check valve" on YouTube, it uses a marble & O ring to seal a 3/4" pvc slip on/threaded fitting that's about a $ 1.50

Thomas Gail Haws said...

Thanks. Good idea.