基于磁致伸缩共振的便携式液体黏度测量仪设计

Portable Liquid Viscosity Measuring Instrument Based on Magnetostrictive Resonance

设计了一种基于磁致伸缩共振的便携式液体黏度测量装置,可用于测量低黏度液体的黏度。在待测液体中,采集磁致伸缩振动片的共振频率,通过事先确定的共振频率和液体黏度计算公式,计算待测液体的黏度。该液体黏度测量装置主要由磁致伸缩振动片、磁铁、线圈、测量电路、按键和液晶屏组成。在测量电路中,单片机控制阻抗转换器测量线圈的阻抗变化,通过阻抗峰的顶点确定振动片的共振频率。通过测量磁致伸缩共振片在4种已知黏度的液体（异丙醇、甲醇、乙醇和丙酮）中的共振频率,确定共振频率和液体黏度的计算公式,该计算公式的测量范围为0.306-1.96MPa·s。对纯水进行测量,测量所得黏度为1.008MPa·s与已知纯水的黏度1MPa·s仅相差0.8%。

This paper designed a portable liquid viscosity measuring instrument based on mag-netostrictive resonance, for measuring the viscosity of low viscosity liquid. In the liquid to bemeasured, the resonant frequency of magnetostrictive vibrator is measured and the viscosity ofthe liquid is calculated by feeding the resonant frequency into the formula of liquid viscosity. Theinstrument is mainly composed of a magnetostrictive vibrator, magnet, coil, measuring circuit,buttons and I.CD screen. In the measuring circuit, the microcontroller measures the impedance ofcoil through an impedance converter circuit and determines the resonant frequency of the vibratorcorresponding to the maximum point in the impedance peak. The fitting formula of liquid viscosi-ty is defined by measuring the resonance frequencies of the magnetostrictive vibrator in four liq-uids （isopropyl alcohol, methanol, ethanol and acetone） whose viscosities are known. The meas-uring range of the fitting formula is 0. 306%1.96 MPa · s. Pure water is tested and the viscositymeasured is 1. 008 MPa · s, of which the error with true value is 0.80%.