Introduction: Bicycle Operated Water Pump (Tuntipump)

This thing here is a fitness trainer connected to a garden pump. Water can be pumped from a level under ground like a well and it can be connected to a sprinkler or tap.

For example a water level 2m under ground and a full-circle impact sprinkler B62 (1.3 bars, 5mm nozzle, 15l/min) like this is a good fitness practice.

Step 1: Design Ideas

The device consists of a bicycle type fitness trainer and an electrical water pump, both dismantled to various degrees, plus a keyless shaft-hub lock, a ribbed pulley-wheel, a ribbed belt, a hinge and metal construction material. The fitness trainer must have a rather fast spinning flywheel that has a evenly lathed edge. An electromagnetic eddy brake is a good indicator for this. The water pump should have 200-300W power, more is too hard to pedal.

The ribbed belt is type PJ6, here it's 1245mm long. It's profile PJ6 is suitable for szenarios with one ribbed wheel and one smooth wheel. It has to be tensioned. So the pump is mounted flippable, tensioning the belt by weight of itself and an extra ballast, also a pump in this case, the green one. To preserve precise radial runout, the position on the axle of the original outer bearing are preserved but replaced by an upright pedestal bearing.

Step 2: The Motor Part

The ribbed wheel is mounted on top of the aluminium style squirrel-cage rotor. That design requires the belt run through a hole in the carrier-plate like on the third picture here. The pump here is a suction pump, which has to be mounted in upright position.

Dismantle the motor. Remove the ventilator. Now remove the housing with the electrical stator and with the electrical connection box. These all are fixed together in one cylindrical part, painted on the outside, blue in this case (not displayed). It's usually done with 3 long screws pointing in the direction of the axle. Now the aluminium style squirrel-cage rotor is exposed like in the first picture.

Now find a keyless shaft-hub lock thingie to be mounted on the rotor. It's shown on the second picture here. Use a thin seamless tube if a spacer is needed, cut it axial if the diameter doesn't math exactly, like in the first picture. Put the shaft-hub lock on, with a screwdriver like in the second picture only if not possible without. Tighten it halfway. Measure the diameter for the ribbed wheel bore (here 62.1mm). Make or order the ribbed wheel and mount it.

Check the spinning direction of the pump before you mount it on the fitness chassis, only one is correct. Now make the surrounding construction to mount it on the chassis, beginning with the pump carrier plate. Mounting the bearing of the pump axle on the carrier plate in a little cross position doesnt matter, but the axle should be parallel to the ground plate, or finally all 4 axis including the hinge axis should be parallel.

Step 3: The Hinged Pump Wing

Check the spinning direction of the pump if not already done. Now make the surrounding construction to mount the pump carrier plate on the chassis with a hinge. Rubber spacers are good for damping the vibrations.

Add a handle near the center of mass, which is near the rear end of the device. Also add a wire or chain connection so the hinged pump doesn't drop if the belt slides down while carrying.

A suction pump like this has to be filled with water first (and emptied in winter again). If the first half meter of the outgoing water tube is not near vertical, pump slowly first until you feel the water has reached the pump. In a permanent installation, any suction pump needs a non-return valve or at least a manual valve so water stays in the pump after operation.

Have fun!