Intelligent liquid turbine flowmeter is a new intelligent instrument which integrates turbine flow sensor and display by using advanced ultra-low power single chip microcomputer technology. Double-row liquid crystal display is used in the field, which has obvious advantages such as compact structure, intuitive and clear reading, high reliability, no interference from external power supply, lightning resistance and low cost. Turbine flowmeter is the main type of velocity flowmeter. When the measured fluid flows through the sensor of the turbine flowmeter, the impeller is forced to rotate under the action of the fluid, and its rotating speed is proportional to the average flow rate of the pipeline. At the same time, the blade periodically cuts the magnetic field lines generated by the electromagnet, changing the magnetic flux of the coil. According to the principle of electromagnetic induction, a pulsating potential signal, that is, an electric pulse signal, will be induced in the coil, and the frequency of this electric pulse signal is proportional to the flow rate of the measured fluid. A flowmeter that uses a turbine to measure. It first converts the flow velocity into the rotational speed of the turbine, and then converts the rotational speed into an electrical signal proportional to the flow.

This flowmeter is used to detect instantaneous flow and cumulative total flow, and its output signal is frequency, which is easy to digitize. In the figure, the induction coil and the permanent magnet are fixed together on the housing. When the ferromagnetic turbine blade passes the magnet, the reluctance of the magnetic circuit changes, thus generating an induction signal. The signal is amplified and shaped by an amplifier and sent to a counter or frequency meter to display the total integrated flow. At the same time, the pulse frequency is converted from frequency to voltage to indicate instantaneous flow. The rotating speed of the impeller is proportional to the flow rate, and the rotating speed of the impeller is proportional to the total flow rate. The output of the turbine flowmeter is FM signal, which not only improves the anti-interference of the detection circuit, but also simplifies the flow detection system. Its range ratio can reach 10: 1, and its accuracy is within 0.2%. The time constant of turbine flowmeter with small inertia and small volume can reach 0.0 1 sec.