The gas flow meter is a new type of flow meter developed and designed using the basic principle of liquid vibration. It is widely used in the measurement and verification of fluid mechanics in manufacturing industries such as petroleum, chemical plants, metallurgical industry, and paper industry. Strong credibility, high accuracy and long life, can accurately measure the instantaneous velocity flow and total flow of liquid within a wide flow range. It will not be harmed by material temperature, working pressure, viscosity, and composition. In addition, it is not blocked, stuck, difficult to accumulate, heat-resistant, pressurized, safe and explosion-proof, suitable for extreme natural environments. The flowmeter is divided into integrated display information and remote transmission display information, and can output differential signals or current data signals and connect to the microcomputer network.
Performance characteristics of gas flowmeter:
1. Temperature and pressure compensation are not needed for gas flow measurement, and the measurement is convenient and accurate. The mass flow or standard volume flow of the gas can be obtained. Zh
2, can measure the gas flow rate as high as 100Nm / s and as low as 0.5Nm / s, can be used for gas leak detection.
3. Good seismic performance and long service life. The sensor has no moving parts and pressure-sensitive parts, and is not affected by vibration to the measurement accuracy.
4. Easy installation and maintenance. Where site conditions permit, non-stop installation and maintenance can be achieved.
5. Digital design. Digital circuit measurement of the whole machine, accurate measurement and convenient maintenance.
It is mainly used for measuring the flow of medium fluid in industrial pipelines, such as various media such as gas and vapor. It is characterized by small pressure loss, large measuring range and high accuracy. It is hardly affected by parameters such as fluid density, pressure, temperature and viscosity when measuring volume flow under working conditions. No moving mechanical parts, so high reliability and low maintenance. Instrument parameters can be stable for a long time. The vortex flowmeter uses a piezoelectric stress sensor with high reliability and can work in the operating temperature range of -20 ° C to + 250 ° C. It has analog standard signals and digital pulse signal output. It is easy to use with digital systems such as computers. It is a relatively advanced and ideal measuring instrument. The range is very wide, the price is relatively cheap, and the application is wide. Zh
Swirl into vortex flowmeter
的 The flow profile of the flow sensor is similar to the profile of the venturi tube. A set of spiral guide vanes is placed on the inlet side. When the fluid enters the flow sensor, the guide vanes force the fluid to generate a violent vortex. When the fluid enters the diffusion section, the vortex is affected by the backflow and starts to rotate twice to form a gyro-type vortex precession phenomenon. The precession frequency is directly proportional to the flow rate, and is not affected by the physical properties and density of the fluid. The detection element can obtain a good linearity in a wide flow range by measuring the precession frequency of the fluid during the second rotation. The signal is amplified, filtered, and shaped by a preamplifier and converted into a pulse signal that is proportional to the flow rate, and then sent to the microprocessor for integration processing together with the detection signals such as temperature and pressure, and then displayed on the LCD screen. Measurement results (instantaneous flow, cumulative flow and temperature, pressure data). The price is relatively medium, and the measurement gas range is slightly lower. It is mostly used to measure fuel gas such as natural gas, liquefied petroleum gas, and oxygen hydrogen.
Radon gas turbine flow meters use turbines for measurement. It first converts the flow rate to the speed of the turbine, and then converts the speed into an electrical signal that is proportional to the flow. This flow meter is used to detect the instantaneous flow and the total accumulated flow, and its output signal is frequency, which is easy to digitize. In the figure, the induction coil and the magnet are fixed on the housing together. When a ferromagnetic turbine blade passes a magnet, the magnetic resistance of the magnetic circuit changes, which generates an inductive signal. The signal is amplified and shaped by the amplifier, sent to the counter or frequency meter, and displays the total accumulated flow. At the same time, the pulse frequency is frequency-voltage converted to indicate the instantaneous flow. The speed of the impeller is proportional to the flow, and the number of revolutions of the impeller is proportional to the total flow. The output of the turbine flowmeter is a frequency-modulated signal, which not only improves the interference resistance of the detection circuit, but also simplifies the flow detection system. Its range ratio can reach 10: 1, and the accuracy is within ± 0.2%. The time constant of the small inertia and small-sized turbine flowmeter can reach 0.01 seconds. Gas turbine flow meter is a relatively ideal trade settlement gas flow meter, which can display temperature, pressure, instantaneous flow rate, cumulative flow rate, daily cumulative flow rate, etc. on the same screen. When the price is relatively high, the requirements for medium cleanliness are relatively high.
Verabar flowmeter is a plug-in flow measurement instrument. A Verabar sensor is inserted into the pipeline. When the fluid flows through the sensor, a high-pressure distribution area is generated in the forward flow direction of the sensor and a low-pressure distribution area is generated at the rear. The sensor has a plurality of pairs of pressure-receiving holes arranged in a certain rule in the high and low pressure regions, and generally measures the total pressure of the fluid, including the static pressure and the average velocity pressure Pl and the static pressure P2. Introduce P1 and P2 into the differential pressure transmitter, and measure the differential pressure △ P = P1-P2, △ P reflects the average velocity of the fluid, so that the flow rate of the fluid can be calculated. It is a typical differential pressure flowmeter. The technology comes from the United States and is widely used in large pipelines with low flow rates. It is equipped with a high-precision differential pressure transmitter to achieve the maximum measurement of large pipelines with low flow rates. Simple cost. , Very good gas flow meter