Performance characteristics of a double chamber twin fluid nozzle

摘要

The performance characteristics of a double chamber twin fluid nozzle are described. In the design, air is always supplied to one of the chambers but is only supplied to both when the air pressure is sufficient to open a diaphragm fitted in the air line. This arrangement allows low volumes of low pressure air to be directed to one of the chambers so as to generate extra coarse to coarse sprays. Increasing the air pressure opens the diaphragm and air enters the second chamber enabling coarse to fine spray sprays to be generated depending on air pressure and liquid flow. In this way spray qualities from fine to extra coarse were generated at flow rates from 800 to 1600 ml min without changing the nozzle tip. Measurements of the spray volume distribution pattern when operating with three different spray liquids and a range of settings gave coefficient of variation values that were consistently less than 10%. Wind tunnel studies using an air pressure of 40 kPa and liquid flow rales of 800, 1200 and 1600 ml min~(-1) showed that drift was less than 25% of that from a conventional reference hydraulic flat fan nozzle.