Educational DIY Water Hand Pump.

Rural areas , especially those situated far from a readily available source of water often have boreholes dug around and fitted with water hand pumps. The water hand pump is a manual hydraulic device which fits the settings of most rural settlements where electricity supply is not well developed. It is operated by the up and down movement of the force rod (pump handle) which results in a gush of water out of the pump's water outlet .

The operation of the pump primarily depends on the two valves located inside/within the cylinder/pump body: the foot valve/check valve/suction valve (at the base) and the piston valve (on the piston).

The downward motion of the force rod/pump handle leads to a consequent upward displacement the pump's piston through the connection of the the piston rod. This upward motion of the piston create a suction pressure which sucks/draws upward whatever fluid the pump is placed in.

The subsequent upward motion of the pump handle leads to the downward displacement of the pump's piston, generally the fluid that was earlier drawn in would be expected to be squished out back but the foot valve prevents this. The valve only allows for the entrance of fluid and would close if an attempt to push the fluid out is made due to the pressure exerted by the fluid itself on the valve against the base of the cylinder thereby sealing the passage way .

The fluid now moves upward the cylinder, through the piston valve passing above the piston itself. This occurs during the downward motion of the piston.

The piston valve operates similarly to the foot valve, it allows the fluid to pass upwards through it while preventing a backflow of the fluid due to the the pressure exerted by the fluid column on top of the valve pushing the valve against the piston surface thereby sealing the passageway.

This repeated up and down motion cause the column of fluid above the piston to go higher till it reaches the water outlet where it gushes outwards into the operator's fetching bucket.

In today's instructable, we will be building a small scale version of the water hand pump with easily available materials. It operates on the same principle as the actual hand water pump. I've selected a transparent cylinder (syringe) for it so we can see how it operates and the movement (opening and closing) of the valves as the water column goes high until it finally pours out at the outlet, teaching us more about the hydraulics of an actual water hand pump.

It is educational, fun and fairly easy to make.

20ml syringe

5ml syringe

Metal rod

Pliers

Hot glue gun and sticks Or epoxy resin glue

Utility knife

Bamboo skewers

Popsicle sticks

Marker/Colour pen

Plastic bag or balloon

Sand paper

Ruler

Screwdriver

Saw

Drinking straws

For the pump handle, we are using some popsicle sticks.

Take a popsicle stick and with the aid of a ruler measure and mark a length of 3cm across the length from one of the ends of the popsicle stick. Cut this 3cm long piece using a pair of scissors. Draw a little circle towards the curved end of the cut stick with a pencil, the drawn circle shouldn't be too close to the edge else the sticks breaks while trying to make a hole in the circle.

Now, using a sharp screw driver or the tip of a hobby knife, gently bore a hole into the stick at the point where the circle was drawn. Trim off the jagged pieces at the edge of the hole using the hobby knife.

Take the remaining part of the cut stick and using the other curved end, measure a length of 5cm, mark it with your pencil and and cut with your pair of scissors .

Do this again with another stick, so that you have two pieces of it with length 5cm each.

Use your pencil to draw two tiny circles at the two ends of the 5cm sticks and bore hole into the circles, make sure the holes are at the same point on both sticks, an easier way to do this is to bore the holes in one of the stick then place it over the other piece to mark the points in which the holes fall on the other stick and then bore it too.

Take another popsicle stick and draw an outline of the pump handle on it about 13cm in length. Make a tiny circle 1cm away from its curved end and another circle 4cm away from the first circle. Using a small saw, cut out the drawn pump handle from the stick (using scissors here might cause the stick to break badly). Use sand paper (60 grit sand paper) to sand off the jagged edge. Bore the holes in the marked circle.

Take a piece of the bamboo skewers and cut two preces each of length 1cm from the skewer and pass it through the holes in the handle sticks as shown in the arrangements. The skewer should fit in tightly into the holes, fastening the pieces together, the pump handle should be moveable up and down around the axis where the skewer passes through it.

For the cylinder of the hand water pump we will be using the tube of a 20ml syringe. First pull the piston out of the syringe so we are left with just the tube.

Before shaping the tube/syringe cylinder into the hand water pump cylinder, we will be joining the pump handle to it. For this, use a black marker or colour pen to draw a straight line in the middle of one of the extending ends at the top of the syringe cylinder. Use the saw to cut through the drawn line to create a gap that reaches the body of the syringe cylinder. Remove all jagged pieces at the edge of the cut with sand paper.

Take the pump handle we made from popsicle sticks and pass the base into the gap we've made and hot glue it into position. In my case, I got my newly purchased hot glue gun clogged 😥 by using a smaller diameter glue stick for it, so as seen in the pictures , I have used epoxy resin hardener glue to secure the pump handle in place (and in subsequent places where glueing is required). To use the resin glue, mix equal amount of resin and hardener from the two tubes and apply the paste over and around the area you want to glue, hold in place till the glue sets (takes about 4 minutes) and leave it somewhere to solidify completely. The end product is very similar to that of hot glue.

Next, use your saw or utility knife to cut off the tiny protruding tip where the needle is attached at the end of the cylinder, the reason for this being that we need the inlet for our pump to be at the centre and so we need to seal off the side positioned inlet that is present on syringes.

Use the sharp tip of the hobby knife to bore hole in the centre of the base of the cylinder, that is, beside the earlier cut side opening. The hole should be almost as big as the diameter of a drinking straw.

Take a drinking straw, cut it into a smaller length, bend it into an L-shape and position one of the ends of the straw over the centre hole on the base of the cylinder, hot glue it into position and also spread the glue to cover and seal the opening that is by its side, allow the glue to harden. As for me, I used the resin glue for this.

To make the piston, we'll be needing the syringe piston which we earlier removed from the syringe cylinder in step 2.

Take the syringe piston and from the piston head side (that is the side that slides in the tube/cylinder), measure, mark and cut a length of 4cm using the saw or utility knife.

The cut piece (4cm) has a circular head and four cross-linked extension forming the length of it. Of these four extensions, cut 1cm off the length of two opposite facing extensions so that we have a flat extending plate of 1cm in length as shown in picture 4 and 5.

Using a colour pen/marker, draw a tiny circle in the centre of the flat extending plate.

The four extensions divide the circular head of the piston into four compartments or quadrants, make two small circular holes in two of these quadrants. Using a sharp screw driver or the tip of a hobby knife, bore holes into the three marked circles. Two of these holes serve as passage way for water up through the piston.

You might expect this to be complicated but no, it's not.

We only need a polyethylene/nylon bag (essentially any plastic bag would do) or any other similar material, you can also use rubber balloons too instead of the polyethylene bags to make the valves; take the plastic bag or balloon and cut a circular piece that is slightly smaller than the diameter of the cylinder from it. Drop this circular piece of plastic film into the cylinder and use a skewer stick or straw to place it properly so that it touches flat on the base of the cylinder covering the passageway of the hole made into the base earlier.

Take a drop/ball of hot glue with the tip of a bamboo skewer and lower it into the cylinder towards a side of the base of the cylinder where the drop of glue would hold the plastic film to the wall of the cylinder while the other portion of the plastic film is free and can easily flap up and down. Allow the glue to harden properly.

To make the valves for the piston (that is the piston valves), since we've made two holes into the head of the piston, we would as well need two valves for the piston.

To do this cut a small rectangle from the plastic film and pinching a portion of one of the corners, cut a curve along the portion you're pinching so you get a cone-shaped tiny piece of the plastic film. To avoid cutting the second valve separately, which would be stressful, I laid two rectangular pieces of the plastic film over each other, then cut off the corner cone to obtain two cones of same size.

Place the two cone plastic films, each in their compartment covering the holes beneath them and use a ball/drop of glue to hold them in place at the corner of each compartment while the remaining portion of the film can freely flap upwards and downwards.

Take a thin long rod metal rod and cut it to a length of 8cm using a pair of pliers, still with the pliers, bend about 1cm length at one end of the rod into a "J" shape and pass the piston into it through the third hole and close the J - shape of the rod into an O - shape using the pliers.

Do the same thing for the other end of the connecting rod/piston rod but this time the rod is passed into the hole at the end of the pump handle.

Take a 5ml syringe and cut away the two ends of it, leaving just a long transparent, graduated tube open at both ends. Cut this open tube at the 2ml mark, now we have a long and a short piece each of tube. At one end of each of the two tubes, at a slant angle of about 45 degrees use the utility knife to cut through the tube.

Take the longer tube and using a sand paper rolled on a cylindrical item, sand a concave groove into its other end so that it can fit onto the body of the pump cylinder.

Glue the two piece (long and short) together at the slanted ends to form an L - shape.

Use a marker/colour pen to draw a circle about 1cm from the top of the pump cylinder, use the hobby knife to bore a hole into the circle made, the hole made should be almost as big as the diameter of the 5ml tube.

Now glue the L - shaped outlet to the bored hole on the pump cylinder using hot glue or resin glue making sure there are no gaps or spaces around the joints. Allow all glues to harden properly.

Take a plastic plate with lid and draw a circle a little bigger than the diameter of a drinking straw on the lid with a colour pen/marker and bore a hole into the circle using the tip of a hobby knife.

Insert the straw at the end of our water hand pump through the hole in the lid of the plastic plate and glue the base of the water hand pump to the lid completely sealing off the hole on the lid.

Fill the plastic plate with water almost getting filled up and then attach the lid which now has the water hand pump glued on it to the plate.

With all the above steps completed and the build of the water hand pump completed, we now put it to use.

Holding the pump handle, move it up and down and watch the flapping movements of the valves in the direction of the upward and downward motion of the piston and watch as water rises into the water hand pump and how the water column passes over the piston (through the piston valve) going higher until it reaches and pours out through the water outlet into my makeshift fetching bucket ( I simply cut the bottom portion of a plastic water bottle for it).

So that's it, now you can easily demonstrate how a water hand pump works in a very practical way to curious minds around you.