Design And Analysis Of Dynamic Throttling Element Flowmeter And Its Transmitter For House Heat Meter

Because of the cold winter in northern China，the annual heating consumptionof energy is enormous. However, the energy efficiency is extremely low. Localgovernments are vigorously promoting the reform of heating system. One of themost important initiatives is to change the implementation of billing policy toaccount heating by volume In order to adapt to the changes in the billing policy, itis necessary to develop a kind of heat meter for the heating system which couldaccurately calculate the volume of heat. For the development of heat meter, what’sthe most important step is the selection of flow meter. There are kinds of flowmeter products，but there is rarely a heat meter based on any kind of flow meterwhich could apply to our heating system perfectly. The main reasons can be listedas follows: firstly the flow meters can easily be blocked by the impurities in water,secondly the small diameter of heating pipeline make general flow meters hard towork, finally the complexity of manufacturing make the price of flow meters high.To solve the above problems, this dissertation focuses on developing a kind of newflow meter.Under the premise of determining the heat meter structure, we propose thenew design of flow meter. The flow meter based on throttling unit learn theadvantages of traditional throttling flow meters which have simple structure, longlife and high accuracy, but abandon the shortages of holes which is easily blocked.Elaborate the working process and measuring principle of flow meter. Establish themechanical model, and divide the flow meter into mechanical module anddetective module.The mechanical module is a venturi tube connected with two metaldiaphragms. Firstly analyze the elastic properties of metal diaphragm by Ansyssoftware, and select a kind of metal diaphragm. Secondly analyze the parameterswhich affect the throttling performance of venturi tube, and design a kind ofventuri tube. Finally simulate the working process of mechanical module, and getoutput parameters.According to the output parameters, we can design the detective module.Propose three kinds of elastomers for the detective module. They are cantilever,force enlarge mechanism and parallel beams with two holes. Discuss the factorswhich affect the detecting performance. And design the structure of theseelastomers.Design a transmitter for the transmission of flow signal. Discuss thecomponents in the transmitter, and design the circuits. The signal transmitterincludes a Wheatstone bridge, a zero modulation circuit, an amplification circuit and a V/I conversion circuit and so on.With the completion of flow meter prototype and its transmitter, we test thestatic characteristics by using a binary flow calibration platform. The staticcharacteristics include linearity, sensitivity, lag and repeatability. Contrasting theperformances, we select the best proposal. Because the output signal of flow meteris received by the transmitter, we can calibrate the output signal of transmitter byusing the binary flow calibration platform. According to the test, not only thefeasibility, but also the excellent performance of the flow meter is beendemonstrated. To be concluded, the flow meter can be applied to the developmentof heat meter.