A PRESSURE REGULATING SYSTEM FOR VARIABLE IRRIGATION FLOW CONTROLS

It is important for an irrigation system to have a stable constant pressure to obtain efficient water management for crops. A simple mechanical flow control system with a pressure-regulating valve was investigated for subsurface drip irrigation and small acreage sprinkler irrigation to maintain constant pressure under variable flow conditions. A submersible pump, booster pump, and centrifugal pump were tested with the control system for the variable flow rates ranging from 9.6 to 222.1 L/min and pressure ranging from 69 to 276 kPa. As long as the pumps were able to provide enough flow to maintain a pressure differential of 124 kPa between control system inlet and outlet, the line pressure remained constant and stable through the test. Standard deviation of the pressure from the flow control system at 69-kPa pressure setting was 0.4 kPa for the submersible pump, 1.2 kPa for the booster pump, and 3.9 kPa for the centrifugal pump. At the 69-kPa pressure setting, the amperage to the booster pump decreased from 11.3 to 8.8 A when the total flow rate in the line decreased from 158.1 to 41.2 L/min. The irrigation system with the flow control avoided pressure pulsation and reduced total energy consumption.