The compressed air flow meterworks according to the Karman vortex theory and can be used to measure the flow of gas, steam, and compressor air. The three-compressed air flow meter has a remote transmission type, a field display type, and a temperature and pressure automatic compensation type.
The compressed air flow meterworks according to the Karman vortex theory and can be used to measure the flow of gas, steam, and compressor air. The three-compressed air flow meter has a remote transmission type, a field display type, and a temperature and pressure automatic compensation type. It can be widely used in chemical, petroleum, metallurgy, light industry, environmental protection, municipal, power and other departments.
You may be interested in what is pressure transmitter.
Ⅱ.The characteristics of compressed air flowmeter
★ No moving parts, no wear, simple structure and long-term stability.
★ Using micro-power high-tech, battery-powered field display type flowmeter, which can run continuously for more than two years.
★ Temperature and pressure compensation integrated design.
★ The current output is electrically isolated and has good common mode interference suppression capability.
★ Simultaneous display of flow value and cumulative flow value, temperature and pressure value, so it does no need to switch in turn.
Ⅲ.Compressed air flowmeter technical parameter:
Flange card / flange connection / plug-in
LCD liquid crystal display
Starting flow rate
Ⅳ.Selection table (basic model)
Compressed air flow meter
Live LCD display
Built-in high-energy battery
External power supply
Automatic temperature compensation
Automatic pressure compensation
Automatic compensation of temperature and pressure
Isolation 4-20mA (two-wire system)
Other communication methods
Nominal diameter and other caliber
Intrinsically safe type
Ⅴ.Main advantages and limitations
(1) The air flow meter has a simple and firm structure and is convenient to install and maintain.
(2) There are many types of fluids, such as liquids, gases, steam, and some mixed-phase fluids.
(3) Compared with differential pressure type and float type flowmeter, the accuracy is high, generally up to ±1%R.
(4) The range width is 10:1 or 20:1.
(5) The pressure loss is small, about 1/2~1/4 of the orifice flowmeter.
(6) Output pulse signal proportional to the flow rate, suitable for total metering, no zero point migration.
(7) In a certain range of Reynolds number, the output frequency signal is not affected by fluid properties (density, viscosity) and composition. The meter factor is only related to the shape and size of the vortex generator and the pipe, and can be verified in a typical medium. And for a variety of media. As shown.
(8) Corresponding vortex detection technology can be selected for different objects.
Relationship between Strauer number and Reynolds number of different measuring media:
Compressed air flowmeter limitations:
(1) Compressed air flow meters are not suitable for low Reynolds number (Ren ≤ 2 × 104) measurements, and are limited in applications with high viscosity, low flow rate, and small diameter.
(2) The instrument with vibration resistance should be selected in the place where the pipe has vibration.
(3) The stability of vortex separation is affected by the sudden distribution distortion and the swirling flow. The straight pipe section should be long enough according to the different types of chokes on the upstream side. Generally, the length of the straight pipe section of the throttle type differential pressure flowmeter can be referred to. Request installation.
(4) Compared with the turbine flowmeter, the meter factor is low, the resolution is low, and the larger the diameter, the lower the diameter, generally applied to small and medium diameters (DN25~DN300).
(5) The instrument is still lacking test data in the application of pulsating flow and mixed phase flow.
The selection and use of device is a key part of using flow meters. At present, the main reason for the use of compressed air flowmeters in China is that the selection is not ideal, so that the flowmeter does not work in the middle and upper areas of the instrument flow range (the instrument signal quality is good, the accuracy is high, and the vibration resistance is good). Some, because the pipeline is not filled with media, the user is not willing to shrink the tube, even beyond the scope of the selected flow meter, can not be measured.
The gauge and specifications of the air flow meter should be selected according to the following principles:
(1) Identify the name and composition of the fluid.
(2) Defining the maximum, common, and minimum flow of the working state.
(3) Identify the highest, most common, minimum working pressure and working temperature.
(4) The viscosity of the medium under working conditions.
(5) Calculate and select the flow range and diameter of the instrument according to the state of the fluid to be measured (liquid, gas, steam).