A PRESSURE REGULATING SYSTEM FOR VARIABLE IRRIGATION FLOW CONTROLS

Abstract

It is important for an irrigation system to have a stable constant pressure to obtain efficient water managementfor crops. A simple mechanical flow control system with a pressureregulating valve was investigated for subsurface dripirrigation and small acreage sprinkler irrigation to maintain constant pressure under variable flow conditions. A submersiblepump, booster pump, and centrifugal pump were tested with the control system for the variable flow rates ranging from 9.6to 222.1 L/min and pressure ranging from 69 to 276 kPa. As long as the pumps were able to provide enough flow to maintaina pressure differential of 124 kPa between control system inlet and outlet, the line pressure remained constant and stablethrough the test. Standard deviation of the pressure from the flow control system at 69kPa pressure setting was 0.4 kPa forthe submersible pump, 1.2 kPa for the booster pump, and 3.9 kPa for the centrifugal pump. At the 69kPa 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 to41.2 L/min. The irrigation system with the flow control avoided pressure pulsation and reduced total energy consumption.