The Development Of The 3L Small Liquid Flow Standard Device

The flow measurement is widely used in industrial and agricultural production,national defense construction,medicine,engineering,scientific research and various fields of social life.Flow measurement plays an important role in improving the production efficiency,ensuring product quality and promoting the development of science and technology.There is no strict according to the design of flow meter verification regulations perfect small liquid flow measurement standard device,can't meet the actual needs of small liquid flow metering.And with the development of medical engineering in our country,medical applications are short of small flow measurement technical support.There is a lack of standard devices to calibrate medical instruments like blood purification device and calibration instrument of blood purification device.This paper studied a 3L liquid flow standard device in order to solve this problem.Main research contents are as follows:(1)the overall design idea of 3L small liquid flow standard device was put forward,and the technical index and design scheme were confirmed.After the analysis of working principle,the mathematical model of the device is established.(2)The piston was guided by linear guide when servo motor was driving the ball screw.The structure that piston rod,linear guide,ball screw,guide bars and grating were parallel was put forward.The selections of components were completed and the 3D design of mechanical structure was finished.(3)The control system and software of 3L small liquid flow standard device were completed by combining MSP430 and Lab VIEW.The device can execute automated verification.(4)3L small liquid flow standard device was completed and a series of experiments and uncertainty evaluation were carried out.It turns out that the device has a good stability and it can measure the flow in the range between 10 m L/min and 2000 m L/min,has a reproducibility superior to 0.06% and the expanded uncertainty is 0.13%.