Characteristic Analysis of Variable Orifice Flow Meter

There are many kinds of method for flow rate measurement nowadays. And orifice flow meter is a most popular instrument of flow rate measurement in industry. But a value of measurement flow rate is in proportion to the square root of pressure difference. So this flow meter has narrow range-ability. And it is very difficult to get high accuracy in range of lower flow rate.The research about the flow meter in which the orifice area is a function of the differential pressure is reported in 1972 [1]. According to this study, the range-ability of flow meter has been improved over a range of 100: 1. But it has not been confirmed in detail the flow rate characteristics by experiments.In this time, we confirmed the flow rate characteristics of this flow meter experimentally. And we studied about the flow rate coefficient and the influence of fluid power upon its flow meter. In addition, we tried to clarify the principle of measurement about this flow meter.