Research On Two-wire Static-blade Pulp Consistency Transmitter

The measurement of the concentration of pulp plays a really important role in theproductive process of papermaking, and gives great influence to the quality of finishedpaper products. Using dynamics method to detective the concentration of pulp has beenproved to be effective in the intermediate-range of the pulp consistency, and is widelyused in papermaking.In the thesis, a new kind of pulp consistency transmitter which is based on thestatic-blade dynamics method was studied. The mechanical construction of thetransmitter is account in the thesis. And a mathematical model of flow velocity, kineticviscosity and the output of the transmitter have been established. Base on themathematical model, a method of flow velocity compensation was put forward and hasbeen proved to be effective by math simulation. The transmitter has been redesigned itscircuit, and can output4-20mA current signal in two-wire form. Meantime, by applyingthe data-processing technology, the transmitter can modify the data to augment thelinearity of the measurement and compensate the error from the flow velocity. In general,the redesigned static-blade transmitter is more accurate in measuring. The relativeaccessorial instrument of the transmitter has been also designed, which can acquisition,display and store the signal form the transmitter, and exchange data with the transmitterby RS485. The singlechip programs of the transmitter and its accessorial instrument weredeveloped. The design methods and the program flowcharts of the singlechip program ofthe transmitter and the accessorial instrument were also accounted in the thesis. In thelast part of the thesis, the experimental data of the transmitter was put forward, and hasbeen analyzed particularly.The research lead to the conclusion that comparing with the traditional static-bladetransmitter, the new transmitter is compactly, light and easily maintenance and can workwith better linearity, stability and accuracy.