Micro-flow Intelligent Electromagnetic Flowmeter And Ls Rotometer Ultra-low Power Design

There are two development directions of flowmeter: one is flowmeters with little volume, little weight, low price and convenient to setup and use. Another is flowmeters with high precision and performance.This paper consists of two parts.Part one: Research on the measurement of low-velocity flow with intelligence electromagnetic flowmeter.At first, the paper analyses the difficulty when measuring the low-velocity flow with common electromagnetic flowmeter. According to result, we use the rectangle-shape pipeline instead of circuit-shape pipeline used commonly to measure the flow. Then we set up the model of rectangle-shape pipeline. We compare it to circuit-shape pipeline on sides of the value of induced electromotive force, pressure loss when liquid flow trough the pipeline and resistance's value of the sensor. We get the result that we can finish the measurement of low-velocity flow by using the rectangle-shape pipeline. This is the theory using to measure the flux of low-velocity flow.Secondly, the paper analyses the virtues and shortcomings of inducing-magnetic mode that use alternating current at 50Hz or rectangle-wave current. Then the paper suggests that the flowmeter should use alternating current to induce the magnetic whose frequency is adjustable. Comparing to inducing-magnetic mode with 50Hz alternating current, we can use lower frequency alternating current to induce the magnetic so that it can eliminate the noise at 50Hz frequency and weaken the noise whose phase lags signal 90?greatly. Comparing to inducing-magnetic mode using rectangle-wave current as the signal, using low frequency to induce magnetic can eliminate (weaken) the differential coefficient noise.Thirdly, it eliminates or weakens all different noise by designing the circuitry effectively in the transforming signal part.At last, the flux signal is inputted to the microprocessor after A/D sampling. Then it finishes all kinds of controlling, displaying and communication function. So, the flowmeter is intelligent.Part two: The research on utra-low power consumption design of LS flowmeter.This part finishes design of LS flowmeter with utra-low power consumption, little volume and high performance according to the second direction of flowmeter development.The problem of consumption puzzles people on the design of single function flowmeter. The flowmeter designed in the past couldn't decrease the consumption so low that the whole system can be supplied by dry battery. The best one is supplied by accumulator. The flowmeter designed in this paper is true utra-low power consumption, and it can be supplied by dry battery.The paper finishes the analyze and design on utra-low power consumption from sides of the design of sensor, the choice and running of microprocessor display with LCD. At last, the paper finishes the flowmeter with utra-low power consumption. This flowmeter hasn't extra demand, so its apply area is very wide. And it is specially applied to area where there isn't industrial electrical source for its utra-low power consumption.The principle used in this paper can be used to other circuit design. The innovation in this paper is list below(1) Use rectangle-shape pipeline so that the inducing electromotive force could be enhanced;(2) Use alternating current whose frequency is adjustable to induce the magnetic;(3) Make the flowmeter intelligent by use the microprocessor;(4) Finish designing the LS flowmeter with utra-low power consumption.