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Turbine flowmeter

Turbine flowmeter

Product Details

I. Overview

The LWGY series of turbine flowmeters have been enhanced on the basis of flowmeters at home and abroad. This product is simple in structure, light in weight, easy to install and maintain, and is mainly used for measurement due to high precision, good reproducibility, and sensitivity. The viscosity of the moving viscosity in the closed pipeline is less than 5×10-6m2/s liquid. For liquids larger than this viscosity, the flowmeter can be first calibrated and then used. The liquid requirements are 1Cr18Ni9Ti, 2Cr13 and corundum Al2O3. Cemented carbide does not corrode and has no impurities such as fibers or particles. If it is used with the display instrument of special function, it can also carry out over-alarming, quantitative control, etc. This product is more suitable for flow metering, and it is also a good choice if energy saving is considered.

 

Second, the working principle

When the fluid to be measured flows through the sensor, the impeller is forced to rotate under the action of the fluid, and its rotation speed is proportional to the average flow velocity of the pipeline, and the rotation of the impeller periodically changes the magnetic resistance value of the magnetoelectric converter. The magnetic flux in the detection coil changes periodically, and a periodic induced potential, that is, an electrical pulse signal, is amplified by the amplifier and sent to the display instrument display.

The flow equations of turbine flow meters can be divided into two types: utility flow equations and theoretical flow equations.

(1) Practical flow equation

Qv = f/k

Qm = qvρ

In the middle

Qv'qm... are volume flow, m3/s, mass flow, Kg/s;

f... the frequency of the flowmeter output signal, Hz;

K... Meter factor of the flow meter, ρ/m3.

The relationship between the coefficient of the flow meter and the flow rate (or the Reynolds number of the pipe) is shown in the figure. As can be seen from the figure, the meter factor can be divided into two segments, a linear segment and a nonlinear segment. The linear segment accounts for 2/3 of the working segment, and its characteristics are related to fluid viscosity and sensor structure size. In the nonlinear section, the characteristics are greatly affected by the bearing friction force and the fluid viscous resistance. When the flow rate is lower than the sensor flow lower limit, the meter factor changes rapidly with the flow rate. The pressure loss and flow rate are approximately squared. Care should be taken to prevent cavitation when the flow rate exceeds the upper flow limit. The shape of a structurally similar TUF characteristic curve is similar, which differs only in terms of systematic error levels.

The meter factor of the sensor is verified by the flow check device. It uses the sensor as a black box and determines its conversion factor according to the input (flow) and output (frequency pulse signal), which is more convenient in practical applications. However, it should be noted that this conversion factor (meter factor) is conditional, and the calibration condition is the reference condition. If it deviates from this condition, it will change. The change depends on the sensor type, pipe installation conditions and fluid property parameters. Depending on the situation.

(2) Theoretical flow equation

According to the momentum moment theorem, the equation of motion of the impeller can be listed.

 

In the middle

J: the moment of inertia of the impeller;

Dw/dt: the rotational acceleration of the impeller;

M1: driving torque of the fluid;

M2: viscous drag torque;

M3: bearing friction resistance torque;

M4: Reluctance torque.

When the impeller rotates at a constant speed, , then M1 = M2 + M3 + M4.

It can be obtained through theoretical analysis and experimental verification.



In the middle

n: impeller speed;

Qv: volume flow;

A: coefficient related to fluid physical properties (density, viscosity, etc.), impeller structural parameters (blade inclination, impeller diameter, flow path cross-sectional area, etc.);

B: coefficient related to the tip clearance of the blade, the flow velocity distribution;

C: coefficient related to the frictional moment.

The theoretical flow equation proposed by scholars at home and abroad is applicable to various sensor structures and fluid working conditions. The hydrodynamic characteristics of turbine instrument characteristics are still unclear, and it has a complex relationship with fluid properties and flow characteristics. For example, when there are vortices and asymmetric velocity distributions on site, the hydrodynamics are very complicated. The meter factor cannot be derived by theoretical formula, and the meter factor still needs to be determined by the real-flow calibration. However, the theoretical flow equation has great practical significance. It can be used to guide the prediction and estimation of the variation of the meter coefficient when designing the sensor structure parameters and changing the field conditions.


Third, product features

  • High precision, generally up to ±1%R, ±0.5%R, high precision type up to ±0.2%R;

  • Good repeatability, short-term repeatability of 0.05% to 0.2%, due to good repeatability, such as frequent calibration or online calibration can get very high precision, is the preferred flow meter in trade settlement;

  • Output pulse frequency signal, suitable for total metering and computer connection, no zero drift, strong anti-interference ability;

  • A very high frequency signal (3~4kHz) can be obtained, and the signal resolution is strong;

  • The range is wide, the medium and large caliber can reach 1:20, and the small diameter is 1:10;

  • Compact and lightweight, easy to install and maintain, and large in circulation capacity;

  • Applicable to high-pressure measurement, it is not necessary to open holes on the meter body, and it is easy to be made into high-pressure type instrument;

  • There are many types of special-purpose sensors, which can be designed into various types of special-purpose sensors according to the special needs of users, such as low-temperature type, two-way type, downhole type, sand mixing type, etc.

  • It can be made into insert type, suitable for large diameter measurement, low pressure loss, low price, continuous flow, easy installation and maintenance.


Fourth, technical parameters

  

Basic parameters

Executive standard Turbine flow sensor (JB/T9246~1999)
Instrument diameter (mm) and connection method 4, 6, 10, 15, 20, 25, 32, 40 with threaded connection
(15, 20, 25, 32, 40) 50, 65, 80, 100, 125, 150, 200 with flange connection
Accuracy level ±1%R, ±0.5%R, ±0.2%R (need to be specially manufactured)
Range ratio 1:10; 1:15; 1:20
Sensor material 304 stainless steel, 316 (L) stainless steel, etc.
Conditions of Use Medium temperature: -20 ° C ~ +120 ° C Ambient temperature: -20 ° C ~ +60 ° C
Relative humidity: 5%~90% Atmospheric pressure: 86kPa~106kPa
Signal output function Pulse signal, 4~20mA signal
Communication output function RS485 communication, HART protocol, etc.
Working power A, external power supply: +24VDC ± 15%, ripple ≤ ± 5, suitable for 4 ~ 20mA output, pulse output, RS485, etc.
B. Internal power supply: 1 set of 3.0V10AH lithium battery, the battery voltage can work normally when it is 2.0V~3.0V.
Signal line interface Basic type: Hausmann connector or comes with three core wire blue; explosion-proof type: internal thread M20×1.5
Explosion-proof grade ExiaIICT4 or ExdIIBT6
Protection level IP65 or higher (customizable)

                                                         

Measuring range and working pressure


Instrument diameter (mm)

Normal flow range (m3/h) Extended flow range (m3/h) Conventional connection method and pressure rating Special pressure and pressure rating (Mpa)
(flange clamp)
DN4 0.04~0.25 0.04~0.4 Threaded connection / 6.3MPa 10, 16, 25
DN6 0.1~0.6 0.06~0.6 Threaded connection / 6.3MPa 10, 16, 25
DN10 0.2~1.2 0.15~1.5 Threaded connection / 6.3MPa 10, 16, 25
DN15 0.6~6 0.4~8 Threaded connection / 6.3MPa 4.0, 6.3, 10, 16, 25
Flange connection / 2.5MPa
DN20 0.8~8 0.45~9 Threaded connection / 6.3MPa 4.0, 6.3, 10, 16, 25
Flange connection / 2.5MPa
DN25 1~10 0.5~10 Threaded connection / 6.3MPa 4.0, 6.3, 10, 16, 25
Flange connection / 2.5MPa
DN32 1.5~15 0.8~15 Threaded connection / 6.3MPa 4.0, 6.3, 10, 16, 25
Flange connection / 2.5MPa
DN40 2~20 1~20 Threaded connection / 6.3MPa 4.0, 6.3, 10, 16, 25
Flange connection / 2.5MPa
DN50 4~40 2~40 Flange connection / 2.5MPa 4.0, 6.3, 10, 16, 25
DN65 7~70 4~70 Flange connection / 2.5MPa 4.0, 6.3, 10, 16, 25
DN80 10~100 5~100 Flange connection / 2.5MPa 4.0, 6.3, 10, 16, 25
DN100 20~200 10~200 Flange connection / 1.6MPa 2.5, 4.0, 6.3, 10, 16, 25
DN125 25~250 13~250 Flange connection / 1.6MPa 2.5, 4.0, 6.3, 10, 16
DN150 30~300 15~300 Flange connection / 1.6MPa 2.5, 4.0, 6.3, 10, 16
DN200 80~800 40~800 Flange connection / 1.6MPa 2.5, 4.0, 6.3, 10, 16

 

Inquiry

Customer Service Hotline:13938765366

Company Telephone:13938765366

公司传真:0755-66803070

Office Mailbox:Tianchenyb@163.com

Company Address:North Section of Yuanxin Road, Xinxiang City, Henan Province

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