Research on a Novel Flowmeter With Parallel Two-Dimensional Pistons as Its Metering Units

Flowmeters play a critical role in hydraulic systems. Following a review of positive displacement flowmeters, we hereby introduce a novel positive displacement flowmeter with parallel two-dimensional pistons as metering units. The working principle involves simultaneously utilizing both the rotational and reciprocation movements of a two-dimensional piston and paralleling two two-dimensional pistons to prevent flow rate fluctuations. Consequently, we established a mathematical model to describe the cam track curves and the displacement of the flowmeter. Meanwhile, the pressure loss is analyzed and the leakage flow rate is estimated to compensate the relative error. Finally, we designed and fabricated a prototype to measure the flow rate with ranges of 1 – 25 L/min. The experimental results show that the prototype has a reading uncertainty of less than 2%, a linearity of around ±3.8% and relative errors of less than ±2.9%. The pressure loss for the prototype increases linearly with the total flow rate and reaches 3 bar at 25 L/min. These characteristics are acceptable considering that this prototype is the first set of two-dimensional piston flowmeters. The shortcomings of this first-generation flowmeter are discussed in the conclusion part to provide guidance to enhance the performance of next-generation prototypes.