Instruments that measure fluid flow are collectively referred to as flow meters or flow meters. The flowmeter is one of the important instruments in industrial measurement. With the development of industrial production, the accuracy and range of flow measurement requirements are getting higher and higher, and the flow measurement technology is changing with each passing day. Various types of flow meters have been introduced to suit various applications. More than 100 flow meters have been put into use. From different perspectives, flow meters have different classification methods. There are two commonly used classification methods. One is to classify according to the measurement principle adopted by the flowmeter: the second is to classify according to the structural principle of the flowmeter.
Sort by measurement principle
a. Mechanical principle:
Instruments belonging to such principles have differential pressure type, rotor type using Bernoulli's theorem;
Impulse type using the momentum theorem, movable tube type;
Direct mass equation using Newton's second law;
a target using the principle of fluid momentum;
Turbine using the angular momentum theorem;
Vortex type using vortex principle of fluid oscillation;
Use the total static pressure difference of the pitot tube type as well as volumetric and sputum, trough and so on.
b. Electrical principle:
Electromagnetic,
Differential capacitor type,
Inductive,
Strain resistance type, etc.
c. Acoustic principle:
Ultrasonic.
d. Thermal principles:
Thermal type,
Direct calorimetry,
Indirect calorimetry and so on.
Ultrasonic flowmeter performance characteristics
Measuring liquid: single fluid such as water, seawater, alkali, etc., turbidity less than 10000ppm, particle size less than 1mm
Pipe material: Ultrasonic penetrating full pipe such as steel, cast iron, PVC pipe, dense texture, no serious corrosion and scaling, allowing thin layer of dense lining
Pipe lining material: rubber, epoxy asphalt, fiberglass, mortar, etc., or unlined
Pipe diameter range: DN15mm~6000mm, plug-in sensor for pipe diameter DN25mm~6000mm
Flow rate range: -32m/s~0~+32m/s, bidirectional flow
Accuracy: ±1.0% of displayed value (under standard conditions). Configure plug-in sensor accuracy up to 0.5%
Linearity: 0.5%.
Signal output: 4-20mA or 0-20mA RS-485
Sensor: It is divided into external clip type and plug-in type. The standard configuration is clip-on. The maximum operating pressure of the plug-in sensor is 3 MPa.
Straight pipe length: upstream >10D, downstream >5D from pump outlet >30D (D: pipe diameter)
Display mode: 2*20 character LCD display with LED backlight
Protection level: IP65
Explosion-proof grade: ExdIIBT4
Fixed ultrasonic flowmeter power supply: AC110V, AC220V, DC8~36V or AC7~30V
Ambient temperature / humidity: Host -20 ° C ~ +80 ° C; sensor -20 ° C ~ +80 ° C or -20 ° C ~ +160 ° C optional, the sensor can be immersed in water, water depth less than 2m.
Liquid turbine flow meter classification and function description
Keywords: liquid turbine flowmeter, diesel liquid turbine flowmeter, pure water liquid turbine flowmeter
First, the liquid turbine flowmeter overview
The liquid turbine flowmeter is the main type of impeller flow (flow rate) meter, and the impeller type flowmeter also has an anemometer and a water meter. The TUF consists of a sensor and a conversion display. The sensor uses a multi-blade rotor to sense the average flow rate of the fluid, thereby deriving the flow or total amount. The rotational speed (or number of revolutions) of the rotor can be detected mechanically, magnetically, and photoelectrically and displayed and transmitted by the reading device.
Second, liquid turbine flowmeter classification
According to the classification of instrument functions, SDLWGY series turbine flowmeters can be divided into 2 categories.
1, turbine flow sensor / transmitter
2, intelligent integrated turbine flowmeter
Third, the liquid turbine flowmeter function description
1, turbine flow sensor / transmitter
This type of turbine flow product itself does not have a live display function, only the flow signal is transmitted far. The flow signal can be divided into pulse signal or current signal (4-20mA); the instrument is low in price, high in integration and small in size, and is especially suitable for use with computer control systems such as secondary display, PLC, DCS.