This cross sectional view shows the sturdiness of the Kulu Valve design. Furthermore the water flow control does not depend upon the small closure orifice normally found in conventional high pressure  valves. 

Steel Construction

This illustration clearly shows the copious flow of water  into the drinking trough allowed by the novel design of this device. No thirsty and impatient cattle damaging the equipment here!

PVC Construction

The PVC construction also shows the frost resistant addition to the valve. This modification to the body of the valve provides a pocket for the liquid to expand into, as it freezes, without damaging the valve.