There are many kinds of gas flowmeters, and different gas flowmeters are suitable for different industries.Today I would like to share with you the principles and types of gas flowmeter selection

I. Selection principle

1, the flow meter selection is in accordance with the production requirements, should start from the actual situation of the meter product supply, comprehensive consideration to determine the flow sampling device and the form of gas flow meter specifications!

2. According to the characteristics of the medium under test, select a reasonable measurement method. According to the requirements of the special parts of the medium under test and the measurement accuracy, insert flowmeter, differential pressure meter with velocity measuring element, ultrasonic flowmeter, or mark method, simulation method and other ineffectual loss methods shall be used to measure the flow.

3, pay attention to the requirements of gas flow meter anti-vibration, the correct choice of gas flow meter specifications, gas flow meter resistance should be slightly greater than the pressure of the medium under test, generally to 1.25 times.Ensure that the gas flowmeter does not leak!

4. For gas flow meters installed on production pipelines for long-term operation, energy losses caused by flow measurement elements should also be considered.Under normal circumstances, in the same production pipeline should not choose a number of large pressure loss measurement elements, such as throttling elements.

Ii. Type selection

Gas flowmeter is a kind of flowmeter based on the principle of directly measuring the flow velocity of full pipe in closed pipe.Industrial applications mainly include:

(1) Turbine flowmeter: when the fluid flows through the turbine flow sensor, the turbine is forced to rotate under the action of fluid thrust, and its speed is proportional to the average flow velocity of the pipeline. The turbine rotation changes the magnetoelectric converter's resistance value periodically, and the magnetic flux in the detection coil then changes periodically, generating periodic electrical pulse signal.Within a certain flow (Reynolds number) range, the electrical pulse signal is proportional to the volume flow of the fluid flowing through the turbine flow sensor.

(2) Vortex flowmeter: the non-streamline vortex generator is placed in the fluid, and the fluid alternately separates and releases two columns of alternate and regular vortex streets on both sides of the vortex generator.In a certain flow (Reynolds number) range, the vortex separation frequency is proportional to the volume flow of the fluid flowing through the vortex street flow sensor.

(3) Precession vortex flowmeter: when the fluid passes through the rotor composed of spiral guide blades, the fluid is forced to rotate strongly around the center line to form a vortex wheel, and the vortex center precession along a conical spiral when passing through the expanded tube.In a certain flow (Reynolds number) range, the precession frequency of vortex flow is directly proportional to the volume flow of the fluid flowing through the precession eddy current sensor.

Time difference type ultrasonic flowmeter: when the ultrasonic wave through the flow of the fluid, in the same propagation distance, along the direction of the downstream and along the direction of the countercurrent propagation velocity is different.Within a wide flow range (Reynolds number), the time difference is proportional to the volume flow rate (average velocity) of the measured flow in the pipeline.