The V-Notch Problem
For places where the water is highly corrosive, the PVC riser pipe is, therefore, a very good option. However, most PVC riser pipes exported from India use a V-shaped metric thread. As a result, this thread often breaks at the joint, an issue known as the V-notch effect, and consequently sends the whole pump assembly down the borehole.
Our Trapezoidal Thread Design
To solve this, we pioneered PVC riser pipes for the India Mark 2 pump, and we developed the trapezoidal thread shown above at both ends of the pipe. Because the thread has no sloping V shape, it resists breaking at the point where standard PVC riser pipes are weakest. In addition, a heavy duty injection moulded coupler joins these pipes together, matching the trapezoidal threads and holding 2 rubber sealing rings to prevent water leakage.
How the Pipe Connects
Meanwhile, the diagram below shows how the water tank assembly and the cylinder assembly connect to the square threads of the PVC riser pipe. Specifically, CI adaptors make this connection possible, since they carry square threads on one side and metric threads on the other.
Overall, this PVC riser pipe system with square threads costs about half as much as GI pipes, and it remains totally corrosion resistant.
Related Pages
India Mark 2 Hand Pump
PVC Pipe with SS Couplings
SS Components for Mark 2
Extra Deepwell Hand Pump