Development of ultrasonic flowmeters

The advantages are considered of a method that eliminates the shortcomings of flow meters with alternate switching of ultrasonic signals and considerably reduces the error of flowrate measurements.Translated from Izmeritel'naya Tekhnika, No. 10, pp. 37–39, October, 1994.     

Hydrodynamic errors of ultrasonic flowmeters

Hydrodynamic errors are analyzed theoretically. The results of experimental investigations of Filatov flowmeters in which these errors are eliminated, are presented. Translated from Izmeritel'naya Tekhnika, No. 9, pp. 36–37, September, 1996.     

Problems of fluid dynamics in ultrasonic flowmeters

This article examines problems encountered in applying the laws of fluid dynamics to ultrasonic flowmeters. These problems were resolved in the design of the Filatov flowmeter URF 3-70. Translated from Izmeritel'naya Tekhnika, No. 5, pp. 37–39, May, 1995.     

Materials and transducers for ultrasonic flowmeters

The construction and operation of a lead zirconate-titanate (TsTS-19) piezoelectric transducer as a component of the model UZR-V ultrasonic flowmeter with an Akustron counter is analyzed. Techniques are proposed for enhancing the operating efficiency of ultrasonic flowmeters. The study has resulted in the development of the UZD-1 and UZD-3 transducers, which utilize the new materials and have parameters superior to those of a standard transducer using TsTS-19 ceramic. The new transducers are recommended for systems designed to monitor cold and hot water flow in conduits from 30 mm to 1000 mm in diameter.Translated from Izmeritel'naya Tekhnika, No. 7, pp. 57–58, July, 1993.     

恒流装置校准活塞气体流量计的方法研究

针对干活塞气体流量计连续测量瞬时流量采用的间断工作方式会造成较大的流场阻力波动,为消除阻力波动对干活塞气体流量计准确校准的影响,研究两种恒流法(体积管气体流量标准装置配合调压阀、皂膜气体流量标准装置传递恒流泵)的校准方法,得到满意的干活塞气体流量计校准结果。恒流泵传递比较法把皂膜气体流量标准装置和干活塞气体流量计在量值溯源图上联系起来,是对气体小流量量值溯源体系的有效补充。     

互相关算法在气体超声波流量计中的应用

针对当前大口径气体超声波流量计存在抗干扰能力差和测量精度低的问题,设计了一种利用互相关算法提高测量精度的气体超声波流量计.即以STM32F407作为核心控制器,采用时差法为测量方法,利用互相关波形匹配算法对信号进行定位处理.通过STM32主控芯片和TDC_GP22计时芯片测量的时间值与互相关算法得到的时间值进行对比参照,得到了精确的测量时间.进而搭建了试验样机并进行了试验测试和数据仿真.结果表明,该算法提高了流量计测量精度,增强了稳定性和抗干扰能力.     

Theoretical analysis of the basic parameters of ultrasonic flowmeters

Conclusions A comparison of the final results of the two methods shows that the analytical expressions for the interchannel phase difference and repetition frequency difference F, and in the case of pulsed circuits also of the pulse propagation time difference , differ in the two methods by their corrections B and B.Errors in using the analytical expressions obtained by the approximate method do not exceed 1% when the hydrodynamic correction B for b_n0.1 is applied. If this value is taken as the basic error, the application of the approximate method is justifiable for pipe diameters exceeding 200 mm with piezoelectric element radii of r10 mm, and for pipe diameters exceeding 100 mm with element radii of r5 mm. Therefore, the application of the approximate method is limited in the main to the range of pipes with large and to a certain extent medium diameters. For the greater part of pipes with medium diameters and those with small diameters, it is necessary to use the analytical expressions obtained by the rigorous method. The use of these equations is also required for pipes with large diameters in designing high-precision flowmeters.