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

Abstract

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 twodimensional 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. INDEX TERMS Fluid power, hydraulic system, hydraulic component, flowmeter, two-dimensional piston.

Research on the Mechanical Efficiency of High-Speed 2D Piston Pumps

“…where Ti2 is the input torque of the balancing set in which the same basic rule applies, and it is unnecessary to repeat the derivation process here. Therefore, the mechanical efficiency, η, of this pump can be calculated using Equation (12). / 2…”

“…The team of the author of this paper has for a long time been devoted to designing new hydraulic components using the two-dimensional (2D) concept, which allows the critical parts of hydraulic components, such as the spool in valves or the piston in piston pumps, to have two working degrees of freedom. The 2D concept was successfully applied to various hydraulic components, such as the 2D vibration exciter, 2D servo valves, 2D flowmeters, and 2D piston pumps [10][11][12]. Traditional 2D piston pumps were previously proposed by linking the 2D designed principle with axial piston pumps [13,14].…”

Numerical and experimental study on the churning losses of 2D high-speed piston pumps

“…There are only two rolling friction pairs in 2D piston pumps instead of the multiple sliding friction pairs in traditional pumps. Meanwhile, this mechanism is also introduced in the flowmeter in order to utilize its characteristic of no flow fluctuation (Ding et al, 2019). In this section, the following paragraphs attempt to briefly and clearly describe the structure and working principle of a 2D high-speed piston pump.…”

Investigation of the Churning Loss Reduction in 2D Motion-Converting Mechanisms

“…The last generation of 2D motion-converting mechanisms, which were applied in both 2D pumps and 2D flowmeters [10,14], adopts a fixed cam guiding rail and pairs of active cone rollers. Contrarily, the new 2D motion-converting mechanism makes the cone rollers fixed on the cylinder, where the cam guiding rails are the active parts rotating and reciprocating in the oil chamber, as shown in Figure 3.…”

“…Since then, some ambitious attempts have been carried out to redefine the design of hydraulic pumps because of the only two rolling friction pairs in 2D piston pumps rather than multiple sliding friction pairs in traditional ones [11][12][13]. Besides, two parallel 2D pistons were also used as metering units for assembling a flowmeter when the no flow fluctuation advantage was noticed [14].…”