Emitter Discharge Sensitivity to Pressure and Temperature

The discharge sensitivities to pressure and temperature of three types of emitters (helical long-path, labyrinth and vortex-type emitters) were determined in the laboratory. The measured discharge sensitivity to pressure was used to calculate the maximal permissible pressure variation in a field for the various emitters. The relative discharge distribution along an experimental pipe with helical long-path emitters was calculated on the basis of the measured temperature distribution and the computed pressure distribution. The resulting relative discharge distribution was curvilinear, in good agreement with the measured values. Under field conditions where water is heated as it flows in pipes exposed to solar radiation, emitter discharge along the second half of the pipe is determined by its specific discharge sensitivity to temperature.