WK-LUW Spiral Vortex Flow Meter

summary:

The intelligent vortex flowmeter is a new type of gas flow meter developed and researched by our company with domestic reliability level. This flowmeter integrates flow rate, temperature, and pressure detection functions, and can automatically compensate for temperature, pressure, and compression factor. It is an ideal instrument for gas measurement in industries such as petroleum, chemical, power, and metallurgy.

Main features of the product

●No mechanical movable parts, not easily corroded, stable and reliable, long service life, long-term operation without special maintenance;

●Using 16 bit computer chips, high integration, small size, good performance, and strong overall functionality;

●The intelligent flowmeter integrates a flow probe, microprocessor, pressure, and temperature sensors, and adopts a built-in combination to make the structure more compact. It can directly measure the flow rate, pressure, and temperature of the fluid, and automatically track compensation and compression factor correction in real time;

●The use of dual detection technology can effectively improve the strength of detection signals and suppress interference caused by pipeline vibration;

●Adopting domestically leading intelligent seismic technology, effectively suppressing interference signals caused by vibration and pressure fluctuations;

●Adopting a Chinese character dot matrix display screen with multiple digits, the reading is intuitive and convenient. It can directly display the volume flow rate under working conditions, the volume flow rate under standard conditions, the total amount, as well as parameters such as medium pressure and temperature;

●Adopting EEPROM technology, parameter setting is convenient, it can be permanently saved, and up to one year of historical data can be saved;

●The converter can output frequency pulses, 4-20mA analog signals, and has an RS485 interface, which can be directly connected to a microcomputer for a transmission distance of up to 1.2km;

●Multiple physical parameter alarm output, which can be selected by the user as one of them;

●The flowmeter head can rotate 360 degrees, making installation and use simple and convenient;

●In conjunction with our company's FM type data collector, remote data transmission can be achieved through the internet or telephone network

●Pressure and temperature signals are sensor inputs with strong interchangeability;

●The whole machine has low power consumption and can be powered by internal batteries or external power sources.

Main purpose

Intelligent spiral vortex flowmeter can be widely used in industries such as petroleum, chemical, power, metallurgy, and urban gas supply to measure various gas flow rates. It is currently the preferred product for natural gas transmission and distribution measurement and trade measurement in oil fields and cities.

Structure and Working Principle

Flow meter structure

The flowmeter consists of the following seven basic components (Figure 1):

1. Vortex generator

Made of aluminum alloy, spiral blades with a certain angle are fixed at the front of the shell contraction section, forcing the fluid to generate strong vortex flow.

2. Shell

It is equipped with flanges and fluid channels of a certain shape. Depending on the working pressure, the shell material can be cast aluminum alloy or stainless steel.

3. Intelligent flowmeter integrator (see Figure 3 for principle)

It consists of temperature and pressure detection analog channels, flow detection digital channels, as well as microprocessor units, LCD driver circuits, and other auxiliary circuits, and is equipped with output signal interfaces.

4. Temperature sensor

Using Pt100 platinum resistor as a temperature sensitive element, its resistance value corresponds to temperature within a certain temperature range.

5. Pressure sensor

The piezoresistive diffusion silicon bridge is used as the sensitive element, and its bridge arm resistance will undergo expected changes under external pressure. Therefore, under a certain excitation current, the potential difference between its two output terminals is proportional to the external pressure.

6. Piezoelectric crystal sensor

Installed at the throat near the expansion section of the shell, it can detect the frequency signal of vortex precession.

7. Racomer

Fixed at the outlet section of the shell, its function is to eliminate vortex flow and reduce the impact on downstream instrument performance.

Working principle

The flow profile of the flow sensor is similar to the profile of a Venturi tube (Figure 2). Place a set of spiral guide vanes on the inlet side, which force the fluid to generate intense vortex flow when it enters the flow sensor. When the fluid enters the diffusion section, the vortex flow is subjected to backflow and begins to undergo secondary rotation, forming a gyroscopic vortex precession phenomenon. The precession frequency is directly proportional to the flow rate and is not affected by the physical properties and density of the fluid. By measuring the secondary rotation precession frequency of the fluid with the detection element, good linearity can be obtained over a wide range of flow rates. The signal is amplified, filtered, and shaped by a preamplifier into a pulse signal proportional to the flow rate, and then sent to the microprocessor for integration processing along with temperature, pressure, and other detection signals. Finally, the measurement results (instantaneous flow rate, cumulative flow rate, temperature, pressure data) are displayed on the LCD screen.

Working principle of flow integrator

Figure 3

The flow integrator consists of temperature and pressure detection simulation channels, flow sensor channels, and microprocessor units, and is equipped with external output signal interfaces to output various signals. The microprocessor in the flowmeter compensates for temperature and pressure according to the gas equation, and automatically corrects the compression factor. The gas equation is as follows:

………………(2)

In the formula:

QN - Volume flow rate under standard conditions (m3/h);

QV - Volume flow rate under operating conditions (m3/h);

Pa - Local atmospheric pressure (KPa);

P - Gauge pressure measured by the pressure tap of the flowmeter (KPa);

PN - atmospheric pressure under standard conditions (101.325 KPa);

TN - Absolute temperature under standard conditions (293.15K);

T - Absolute temperature of the measured fluid (K);

ZN - compressibility coefficient of gas under standard conditions;

Z - compressibility coefficient of gas under working conditions;

Note: When calibrating with a bell jar or negative pressure, take ZN/Z=1, and for natural gas (ZN/Z), 1/2=FZ is the over compression factor. Calculate according to the formula in the standard SY/T6143-1996 of China National Petroleum Corporation.

Main technical parameters and functions:

Flow meter specifications, basic parameters, and performance indicators

Note: 1. Accuracy: refers to the system accuracy after temperature and pressure correction;

2 Standard state conditions: P=101.325KPa, T=293.15K

3. Usage conditions:

Environmental temperature: -30 ℃ to+65 ℃

Relative humidity: 5% to 95%

Medium temperature: -20 ℃ to+80 ℃

Atmospheric pressure: 86KPa~106KPa