How many kinds of flow meters are there?
Displacement flowmeterA volumetric flowmeter is equivalent to a standard volume container that continuously measures the flow medium. The greater the flow rate, the more the number of measurements, the higher the frequency of output. The principle of displacement flowmeter is simple and suitable for measuring fluid with high viscosity and low Reynolds number. According to the rotary body shape is different, the production of products: elliptical gear flowmeter, turbine flowmeter for measuring liquid flow (flowmeter), rotary piston and scraper flowmeter; suitable for measurement of gas flow servo type volumetric flowmeter, diaphragm type flowmeter and Jane.
Differential pressure flowmeter (pressure drop flow meter)Differential pressure type flowmeter by the first device and the two device. A device called the flow measurement, it is installed in the pipeline of the measured fluid, and flow (velocity) is proportional to the pressure difference for two flow display device. The two device is called display instrument. It receives the differential pressure signal measuring element is generated, and convert it to the corresponding flow display. A device for ordinary differential pressure flowmeter throttling device or dynamic pressure measuring device (Pitot tube, pitot tube etc.). The two unit is all kinds of mechanical, electronic and combined differential pressure meters. It is equipped with flow meter. The differential pressure sensitive elements of differential pressure gauge are mostly elastic elements. Since the differential pressure and the flow are square root, the flow meter is equipped with an open square device to linearize the flow scale. Most meters also have a flow integrating device to display the cumulative flow for economic accounting. This method of measuring flow by using differential pressure has a long history and is quite mature. All countries in the world are generally used in more important occasions, accounting for about 70% of all kinds of flow measurement methods. This kind of meter is used to measure the flow rate of main steam, water supply and condensed water in power plant.
Vane wheel flowmeterThe principle of the impeller type flowmeter is to place the impeller in the tested fluid and rotate under the impact of the fluid flow. The speed of the impeller is used to reflect the magnitude of the flow. A typical vane type flow meter is a water meter and a turbine flow meter. The structure of the utility model can be a mechanical drive, an output type or an electric pulse output type. The accuracy of the water meter for general mechanical transmission is low, the error is about 2%, but the structure is simple and the cost is low. The domestic water meter has been produced in batches and standardized, universal and serialized. The accuracy of turbine flowmeter output by electric pulse signal is higher, and the general error is + 0.2% - 0.5%.
