The flange type liquid vortex flowmeter is an instrument used for measuring pipelines. The working principle of this instrument is to generate regular vortices. Its body does not come with connecting flanges, and its characteristics are small size, simple and compact structure.

Composition and function of liquid flange turbine flowmeter

(1) Shell (body): It can withstand the pressure of the measured fluid, fix the installation of detection components and connecting pipelines. The shell is made of non-magnetic stainless steel or hard aluminum alloy.

(2) Guiding body: It plays a role in guiding and rectifying fluids, as well as supporting impellers. It is usually made of non-magnetic stainless steel or hard aluminum materials.

(3) Turbine (impeller): The detection element of a flow meter, made of highly magnetic material. There are several types of impellers, including straight blades, spiral blades, and T-shaped blades. The dynamic balance of the impeller directly affects the performance and service life of the instrument.

(4) Shaft and bearings: support the rotation of the impeller.

(5) Signal detector: Famous variable reluctance type.

Working principle of liquid turbine flowmeter:

A liquid turbine flowmeter is a type of flow meter that, when fluid flows through a sensor housing, the blades of the impeller have a certain angle with the flow direction, and the fluid’s impulse causes the blades to have a rotational torque. After overcoming the friction torque and fluid resistance, the blades rotate. After the torque is balanced, the speed is stable. Under certain conditions, the speed is proportional to the flow rate. Due to the magnetic conductivity of the blades, they are in the magnetic field of the signal detector. The rotating blades cut the magnetic field lines and periodically change the magnetic flux of the coil, causing electrical pulse signals to be induced at both ends of the coil. This signal is amplified and shaped by an amplifier to form a continuous rectangular pulse wave with a certain amplitude, which can be transmitted far to the display instrument to display the instantaneous flow rate and cumulative amount of the fluid.

Advantages and characteristics of liquid flange turbine flowmeter:

1. High precision, generally up to ± 1% R and ± 0.5% R (R refers to reading error);
2. Good repeatability, short-term repeatability can reach 0.05% to 0.2%. It is precisely because of good repeatability that frequent calibration or online calibration can achieve extremely high accuracy, and it is a commonly used flowmeter in trade settlement;
3. On site display, instantaneous flow and cumulative flow;
4. Can obtain high frequency signals with strong signal resolution;
5. Wide range ratio, up to 1:20 for medium and large apertures, and 1:10 for small apertures;
6. Compact and lightweight structure, easy installation and maintenance, and high circulation capacity;
7. Can be made into an insertion type, suitable for measuring large diameters, with low pressure loss, low price, can be removed without interruption, and easy installation and maintenance.
8. Support temperature and pressure measurement, convenient for gas medium temperature and pressure compensation needs;
9. Support flow rate conversion display function, convenient for on-site viewing of current flow rate;
10. Support split screen display function, which can enlarge and display single or two parameters (temperature, pressure, operating conditions, flow rate and flow rate under standard conditions, etc.) on the screen;
11. Supports 4-20mA output, pulse (equivalent) output, alarm output, and RS485 communication output.

Technical parameters of liquid turbine flowmeter:

property	Technical parameter
Gauge aperture	4、6、10、15、20、25、32、40 、50
accuracy level	±1%R、±0.5%R、±0.2%R（Require special order）
Range ratio	1:10；1:15；1:20
Instrument material	316（L）Stainless steel
Medium temperature	-20～＋120℃
Environmental condition	Temperature -10 ~ +55℃, relative humidity 5% ~ 90%, atmospheric pressure 86 ~ 106Kpa
Output signal	Sensor: pulse frequency signal, low level ≤0.8V high level ≥8V; Transmitter: two-wire system 4 ~ 20mADC current signal;
Power supply	Sensor: +12VDC, +24VDC (optional); Transmitter: +24VDC; Field display type: instrument comes with 3.2V lithium battery;
Signal transmission line	STVPV3×0.3 (three-wire system), 2×0.3 (two-wire system);
Transmission distance	≤1000m；
Signal line interface	Basic model: Hausmann connector or three-core cable; Explosion-proof type: internal thread M20×1.5;
Explosion-proof class	Basic type: non-explosion-proof products; Explosion-proof type: ExdIIBT6
Class of protection	IP65

Product selection

Selection of liquid turbine flowmeter:

1. Measure the medium. Liquid turbine flowmeter is a velocity flowmeter that first converts the flow rate of the medium into the rotational speed of the turbine, and then converts the rotational speed into an electrical signal proportional to the flow rate. Its principle determines the type of measuring medium, which can only be liquids without fiber or particle impurities such as water, pure water, organic liquids, inorganic liquids, etc. Because fibers, particle impurities, etc. may entangle the blades of the turbine or cause losses, which in turn can affect measurement accuracy and even stop rotating.
2. Pipeline diameter. Unlike other flow meters, the diameter of turbine flow meters can be made very small, theoretically reaching DN4, while other flow meters can generally only reach DN15 or above. However, the upper limit of the diameter of the turbine flowmeter is also very small, theoretically only up to DN200, which can also meet most of the market demand. Turbines are often used in high-precision applications, such as quantitative control, and many turbine flow meters are used.
3. Measurement accuracy. There are several levels of accuracy for turbine flow meters, with the conventional ones being 0.5 and 1.0. These two levels can basically meet the needs of most industrial sites. However, in some situations where high precision is required, higher levels are often needed.
4. Medium viscosity. As mentioned earlier, the principle of turbine flowmeter is to convert the flow rate of the medium into the rotational speed of the turbine, and then convert the rotational speed into an electrical signal proportional to the flow rate. The principle determines that turbine flow meters are not suitable for measuring excessively viscous liquids, as it may affect the rotation of the impeller (in this case, elliptical gear flow meters are more suitable). In theory, the viscosity of the medium in a turbine flowmeter should be less than 5 × 10-6m2/s (for liquids larger than 5 × 10-6m2/s, the flowmeter should be calibrated with real liquid before use). Simply put, the viscosity should be lower than that of edible oil.
5. Nominal pressure. According to the current market demand, the main output is 1.0Mpa; 1.6Mpa; 2.5Mpa; 4.0Mpa; 6.3Mpa (other pressure levels can be customized and supplied according to the agreement).
6. Medium temperature. According to the current market demand, the main temperature range is -20 ℃ to+120 ℃ (stainless steel measuring tube). If a larger range is needed, you can consult the manufacturer for customization.
7. Power supply. According to the current market demand, there are mainly 3.6V lithium batteries; 12VDC; There are three power supply modes available, 24VDC. You can choose the power supply mode that suits you according to the on-site working conditions.
8. Output signal. According to current market demand, there are mainly three wire pulse output and two-wire 4-20mA output. In addition, some situations may require digital output, and we can also provide Modbus RS485 communication and RS232 communication.

Installation matters

Installation instructions for liquid turbine flowmeter:

1. Installation location

The pipeline must be completely filled with liquid. It is important to keep the pipeline completely filled with liquid at all times, otherwise the flow display may be affected and measurement errors may occur.

Avoid bubbles. If bubbles enter the measuring tube, the flow display may be affected, which may lead to measurement errors.

2. Installation site and requirements

(1) Sensors should be installed in a location that is easy to maintain, with no vibration, strong electromagnetic interference, or thermal radiation in the pipeline?

(2) Horizontal installation of sensors requires that the pipeline should not have any visible tilt (generally within 5 °), and vertical installation of sensors should also have a verticality deviation of less than 5 °. In places where the flow cannot be stopped, a bypass pipe and a reliable shut-off valve should be installed, and the measurement should ensure that the bypass pipe is leak free.

(3) At the location where the sensor is installed in the newly laid pipeline, a short pipe is first connected to replace the sensor. After the “line sweeping” work is completed and the pipeline is confirmed to be clean, the sensor can be officially connected

(4) If the fluid contains impurities, a filter should be installed on the upstream side of the sensor, and the pipeline should be regularly cleaned to discharge sediment impurities; If the measured liquid contains liquid, an air purifier should be installed on the upstream side of the sensor. The discharge and exhaust ports of filters and air purifiers should be connected to a safe location.

(5) When installing sensors outdoors, measures should be taken to avoid direct sunlight and rain.

3. Required length of upstream and downstream straight pipe sections

Turbine flow meters are sensitive to flow velocity distribution distortion and rotational flow in pipelines. When entering the sensor, turbulence should be fully developed. Therefore, necessary straight pipe sections or rectifiers should be equipped according to the type of upstream flow resistance components of the sensor, and the length of the straight pipe sections at the inlet and outlet should be required.