The turbine flowmeter first converts the flow rate into the rotation speed of the turbine, and then converts the rotation speed into an electrical signal proportional to the flow rate.
This kind of flowmeter is used to detect instantaneous flow and total totalized flow. Its output signal is frequency and is easy to digitize.
The turbine flowmeter induction coil and the permanent magnet are fixed together on the housing.
When the ferromagnetic turbine blade passes through the magnet, the magnetic resistance 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 a frequency meter to display the total accumulated flow.
The turbine flowmeter simultaneously passes the pulse frequency through the frequency-Voltage conversion to indicate instantaneous flow.
The rotation speed of the impeller is proportional to the flow rate, and the rotation speed of the impeller is proportional to the total amount flowing through.
The output of turbine flowmeter is a frequency modulated signal, which not only improves the anti-interference performance of the detection circuit, but also simplifies the flow detection system.
Its range ratio can reach 10:1 and its accuracy is 0. Within 2%.
The time constant of turbine flowmeter with small inertia and small size can reach 0. 01 seconds.
In Europe and the United States, turbine flowmeter is the second legal Natural gas flowmeter after orifice flowmeter. It has developed into a variety of natural gas flowmeters with full series, multiple specifications and mass production scale.
The standard specification of turbine flowmeter is also very complete, but there are also some shortcomings: the requirement for cleanliness of measuring medium is high, and the service life is limited.
However, according to foreign users, 8 ~ was used for 240 units ~ The 15-year flowmeter was checked periodically and it was found that the deviation of instrument accuracy was still within the specified range.
Turbine flowmeter in addition, the turbine flowmeter adopts a highly efficient rectifier and a turbine flow sensor to form a gas turbine flowmeter with integrated structure, under the condition that the upstream side flow inhibitor is elbow or semi-open stop valve, only 2D straight pipe section length is required, which is a prominent feature for narrow installation space for urban use.
Turbine flowmeter is the main type of velocity flowmeter. When the measured fluid flows through the turbine flowmeter sensor, under the action of the fluid, the impeller rotates under force, and its rotating speed is proportional to the average flow rate of the pipeline. At the same time, the blade periodically cuts the magnetic lines of force generated by the electromagnet to change the magnetic flux of the coil. According to the principle of electromagnetic induction, pulsating potential signals, I . e. electric pulse signals, will be induced in the coil, the frequency of this electrical pulsation signal is proportional to the flow rate of the measured fluid.
Among all kinds of flowmeters, turbine flowmeter, volumetric flowmeter and Coriolis mass flowmeter are three kinds of products with the best repeatability and accuracy, and turbine flowmeter has its own characteristics, for example, the structure is simple, the processing parts are few, the weight is light, the maintenance is convenient, and the circulation capacity is large (The same caliber can pass through the flow)And can adapt to high parameters (High temperature, high pressure and low temperature)Wait.
So far, this type of flowmeter products can reach the technical parameters: caliber 4-
750, pressure 250MPa, temperature-240-
700 ℃, the other two types of flowmeters with technical parameters like this are difficult to reach.
Turbine flowmeter is widely used in the following measurement objects: petroleum, organic liquid, inorganic liquid, liquefied gas, natural gas, gas and cryogenic fluid.
Turbine flowmeter is widely used in foreign transportation and gathering stations of liquefied petroleum gas, refined oil and light crude oil, and in the first and last stations of large crude oil transmission pipelines for trade settlement.
Turbine flowmeter is second only to orifice meter in Europe and the United States. Only Holland uses more than 2600 gas pipelines of various sizes with pressures ranging from 0. 8MPa to 6.
5MPa gas turbine flow meters, they have become excellent natural gas flow meters.
The excellent metering characteristics of turbine flowmeter are favored by people, but the impression given to people is that the moving parts have a short service life and are inevitably hesitant in selection. Through people's unremitting efforts, should say the great change.
As the most common flowmeter, turbine flowmeter has developed into a mass production scale of multiple varieties, full series and multiple specifications.