Insertion vortex flow meter

I. Overview

Dear Customer, Thank you for using our products. To help you better understand, install, and use our series of vortex flow sensors, please carefully read this manual before installation. It will provide you with information and precautions regarding measurement principles, equipment selection, installation methods, commissioning methods, and troubleshooting, helping you to better utilize our products.
The LUCB type represents a full-tube insertion vortex street. It is widely applicable in industries such as petroleum, chemical, pharmaceutical, papermaking, metallurgy, power, environmental protection, and food, for measuring the flow rate of various gases, liquids, steam, and other low-viscosity fluids. It can also be used for measuring turbid liquids containing small particles and impurities.
*Our patented vortex street with a non-disconnecting, detachable sensor head is a unique design and manufacturing process that allows for sensor head replacement and maintenance without affecting fluid flow in the pipeline. Due to its high reliability, the non-disconnecting, detachable vortex street is widely used in various critical applications and as a control instrument in automated instrumentation systems.
*The low-velocity vortex street with its unique design eliminates the contradiction of cumbersome pipe reduction for small fluid flow rates. When measuring low flow rates, the low-velocity vortex street can be installed directly without pipe reduction, yet it can measure extremely low flow rates below the lower limit of vortex street flow rates for pipes of the same diameter. It is simple and convenient to use, reducing user costs.
Our company's explosion-proof vortex flow sensors are designed and manufactured according to the relevant provisions of GB3836.1-2000 "Electrical Apparatus for Explosive Gas Atmospheres - Part 1: General Requirements", GB3836.2-2000 "Electrical Apparatus for Explosive Gas Atmospheres - Part 2: Flameproof Enclosures 'd'", GB3836.2-2000 "Electrical Apparatus for Explosive Gas Atmospheres - Part 4: Intrinsically Safe 'i'", and GB3836-83 "Explosion-proof Electrical Apparatus for Explosive Atmospheres". They have been inspected by an inspection unit designated by the national labor safety department and have obtained explosion-proof certificates. The intrinsically safe explosion-proof type has an explosion-proof rating of ExiaⅡCT4. The flameproof type has an explosion-proof rating of ExdIICT6, which is the highest level of flameproof enclosure.

II. Working Principle The vortex shear sensor measures the flow rate of steam, gas, and low-viscosity liquids based on the theories of vortex generation and the relationship between vortexes and flow rate developed by Karman and Strohal. As shown in Figure 1, a triangular prism, the vortex generator, is vertically inserted into the meter body. When a medium flows through the meter body, Karman vortices are alternately generated behind the prism in opposite directions in a regular pattern. The separation frequency F of the vortexes is proportional to the flow velocity V of the medium. By detecting the number of vortices through the sensor head, the fluid velocity can be calculated, and the volumetric flow rate of the measured medium can be calculated based on the meter body diameter.

The calculation formula is as follows:
F = St * V / (1 - 1.27 * d / D) Formula 1
Q = 3600 * F / K Formula 2
M=Q*ρ Formula 3
● F: Vortex frequency generated by fluid flowing through a vortex shear prism (unit: Hz)
● St: Strohal constant (unit: infinite manganese)
● V: Fluid velocity inside the pipe (unit: m/s)
● d: Width of the triangular prism inside the vortex street meter (unit: m)
● D; Internal diameter of the vortex street gauge (unit: m)
● Q: Instantaneous volumetric flow rate (unit: m³/h)
● K: Instrument coefficient of vortex street (unit: number of pulses/cubic meter)
● M: Instantaneous mass flow rate (unit: kg/h)
● ρ: Fluid density (unit: kg/m³)
The instrument coefficient K value varies depending on the diameter of the vortex flow sensor. Its specific value is obtained through actual calibration using a flow calibration device. It represents the number of pulses generated per cubic meter, or the number of vortices generated when one cubic meter of fluid flows through one side of a triangular prism.

III. Technical Parameters
3.1 Physical Parameters ● Nominal Diameter: LUCB type insertion vortex street Φ200-Φ2000
● Measuring medium: liquid, gas, saturated steam, superheated steam ● Standard conditions: P = 0.101325 MPa; T = 20℃
● Permissible ambient temperature: -20℃ to +55℃ (standard type); -20℃ to +40℃ (intrinsically safe type)
● Atmospheric pressure: 86 kPa～106 kPa
● Relative humidity: 5%-95%
● Medium temperature: LUCB type (insertion vortex shear: -40℃ to +250℃)
● Pressure rating: The flanges of the LUCB type insertion vortex gasifier are all manufactured according to the PN1.6MPa pressure rating; when the operating pressure is higher than the factory pressure, please specify the corresponding pressure rating when ordering.
● Flange Standard: The flange connection type conforms to the standard GB9119.8-88.
● Accuracy class: LUCB type 2.5; (1.0 and 1.5 classes require contract supply)
● Explosion-proof rating: Intrinsically safe explosion-proof type ExiaⅡCT4; Flameproof type ExdⅡCT6
● Protection rating: IP54, IP65
● Body material: 1Cr18Ni9Ti (other materials are available by agreement)

3.2 Electrical Parameters ● Operating Voltage: 24VDC, 3.6VDC lithium battery (battery life greater than 2 years, for on-site display type only).
● Output Signal ※ Voltage pulse corresponding to instantaneous flow rate under operating conditions (low level ≤ 1V, high level ≥ 6V, pulse width ≥ 10µs)
※ Instantaneous flow rate under operating conditions corresponds to two-wire 4-20mA output. ● Communication method: RS232, RS485 or HART protocol (the above communication methods require contract supply).
● Display method: On-site LCD dual-line display: can simultaneously display instantaneous flow rate and cumulative flow rate.

3.3 Selection Parameters
3.3.1 External Structure and Dimensions of LUCB Type Vortex Flowmeter All LUCB type insertion vortex flowmeters use a DN100 standard flange at the connection between the flowmeter body and the pipeline. All flanges conform to GB9119.8-88 standard. The external dimensions of the vortex flowmeter are shown in Figure 2 and Table 1.

Schematic diagram of the external structure of the LUCB type vortex street

3.3.2 Calculation of the Measurable Flow Range of LUCB Type Insertion Vortex Shear ※ Minimum Operating Condition Volumetric Flow Rate Calculation Formula for Gas and Liquid: Qmin=3600*Vmin*（π*D /4） Formula 5
※ Formula for calculating the maximum operating volumetric flow rate of gas and liquid: Qmax = 3600 * Vmax * (π * D / 4) Formula 6
※ Formula for calculating the minimum standard condition volumetric flow rate of gas: QNmin = Qmin * [(P_standard + P_min) * (273.15 + T_standard) * Z] / [P_standard * (273.15 + T_min)] Formula 7
※ Formula for calculating the maximum standard-condition volumetric flow rate of gas: QNmax = Qmax * [(P_standard + P_engine) * (273.15 + T_standard) * Z] / [P_standard * (273.15 + T_engine)] Formula 8
※ Gas density calculation formula ρ = 2695ρnstandard(P + P_I) / (273.15 + T_I) Formula 9
● Qmin—Minimum operating volumetric flow rate of fluid measurable by insertion vortex shear (unit: m³/h)
● Qmax—Maximum operating volumetric flow rate of fluid that can be measured by an insertion vortex shear (unit: m³/h)
● Vmin—Minimum operating velocity of fluid that can be measured by insertion vortex shear (unit: m/s, see Table 7)
● Vmax—Maximum operating velocity of fluid that can be measured by insertion vortex shear (unit: m/s, see Table 7)
● D—Insertion vortex street measurement aperture (unit: m)
●π — Pi, 3.1415926
● QNmin—Minimum standard volumetric flow rate of gas measurable by insertion vortex shear (unit: m³/h)
● QNmax—Maximum standard volumetric flow rate of gas measurable by an insertion vortex shear (unit: m³/h)
● T standard—Standard temperature, typically 20℃. (Unit:℃)
● T_工 — Temperature of the gas under test (unit: °C)
● P standard — standard atmospheric pressure (taken as absolute pressure equal to 0.101325 MPa)
● P_工 — Gauge pressure of the gas being measured under operating conditions (unit: MPa)
● Z—Measures the compressibility of the fluid (typically 1.0 for gases).
● ρ—Density of gas under operating conditions (unit: kg/m³)
● ρn — Density of gas under standard conditions (unit: kg/m³)

※ The calculation method for the flow rate range when measuring steam using the LUCB type insertion vortex street is as follows:
● Refer to Table 4 or Table 5 based on the steam temperature and gauge pressure to obtain the steam's operating density ρ.
● Based on the steam operating density ρ, refer to Table 7, Gas Column, to obtain the minimum operating velocity Vmin or maximum operating velocity Vmax that can be measured by the insertion vortex shear.
● Based on the known measuring pipe diameter of the insertion vortex street, calculate the minimum operating volumetric flow rate Qmin or the maximum operating volumetric flow rate Qmax using formulas 5 and 6.
● Finally, multiplying the operating density ρ by Qmin or Qmax yields the mass flow rate range for steam measurement using insertion vortex shears of different diameters.

IV. Installation Requirements
4.1 Instruments should not be installed on pipelines subject to strong vibrations, otherwise the measurement accuracy will be affected. If installation on a vibrating pipeline is unavoidable, vibration reduction measures should be taken, such as: adding pipeline support points near the upstream 2D; adding flexible pipe transitions, provided that the straight pipe section requirements are met.
4.2 Longer straight pipe sections should be reserved on both the upstream and downstream sides, and the straight pipe sections should meet the requirements of Table 1.
Table 1 Straight Pipe Section Requirements
Upstream pipe conditions: Upstream straight pipe length, downstream straight pipe length, concentric contraction, fully open gate valve ≥15D ≥5D
A 90° bend ≥20D ≥5D
Two 90° bends on the same plane ≥25D ≥5D
Two 90° bends on different planes ≥40D ≥5D
Control valve, half-open valve ≥60D ≥5D

4.3 Vortex flow meters can be installed vertically, horizontally, or at an angle on pipes. For vertically installed flow meters, the fluid flow direction must be from bottom to top. When measuring liquids, the flow meter pipe must be filled with liquid.
4.4 The inner diameter of the pipe should be as consistent as possible with the inner diameter of the flow meter. If they are not consistent, a pipe with a slightly larger inner diameter than the flow meter should be used. The inner diameter of the pipe, the inner diameter of the flow meter, and the sealing gasket must be installed concentrically, and the sealing gasket must not protrude into the pipe.

4.5 New pipelines must be carefully cleaned before instrument installation to avoid damaging the instruments. When installing instruments, ensure that the flow direction markings on them match the fluid flow direction in the pipeline. Valves should be opened and closed slowly during commissioning to avoid sudden impacts.
4.6 Installation method and welding method
The installation of LUCB type vortex streetpers should ensure reliable welding, the flatness and smoothness of the inner wall of the pipe within the straight pipe section, and axial concentricity between clamp-on flanges. For insertion type vortex streetpers, the parallelism between the connecting short flange and the pipe axis should be ensured. The specific installation method is shown in the figure above.
After the initial assembly of the meter body is completed, when the measured medium is steam or other high-temperature media, the flange bolts should be retightened after the pipeline is filled with the medium. The pipeline should also be insulated to prevent damage to the vortex amplifier due to excessive ambient temperature.

Cable connection:
Use an AVPV 2 * 0.5mm² dual-core shielded cable to enter through the inlet hole and connect the wires as shown in Figure 4.
Figure 4
To prevent electromagnetic interference, the negative terminal of the 24V power supply must be properly grounded! If you need to extract a 1-5V voltage output signal, you can connect a 250-ohm precision resistor as shown in the diagram.
To verify the flow coefficient of the flow meter, the flow pulse signal can be led out from terminal P as shown by the dotted line in the figure and connected to the calibration equipment. Note that at this time, the jumper plug should be inserted into jumper 9 on the front circuit board to turn on the power to the pulse amplifier circuit so that there is pulse output.
★After the test is complete, the jumper connector must be unplugged! Otherwise, the current output will be invalid.

V. Parameter Setting and Adjustment
5.1 Button Configuration Operation
The operation process of button (6) is explained in detail below.
5.1.1 Setting and modifying instrument coefficients (setting range: 0.01-999999.99)
Press the function key "F" to display "SET C", which will then show the previously set instrument coefficients, with the highest digit flashing. Normally, the instrument coefficients should not be modified. Press "F" again to confirm and proceed to the next function. If you need to modify them, press the "+1" key; the flashing digit will automatically increment by 1 until the desired value is reached. Then press the ">" key to move the flashing digit to the right to set the next digit. To increase the number of digits in the instrument coefficient, repeatedly press the ">" key; the flashing digit will move from the lowest digit to the highest digit for setting the higher digits.
After setting, press the "F" key to confirm. The display "C PASS" indicates that the modification of the instrument coefficients has been approved.
(Note: a. If the instrument coefficient needs to be modified midway, the cumulative total should be recorded. After the modification is completed, the cumulative total should be cleared and recalculated.)
b. If the instrument coefficient is greater than 10000, the decimal part will be ignored.
5.1.2 Setting and modifying the low flow cutoff value (setting range: 0.01-9999.99)
After setting the instrument coefficients, the display "SET CUT" will indicate that the small flow cutoff value can be set, using the same method as in 5.1.1. Once set, press the "F" key to confirm, and "CUT PASS" will be displayed to indicate success.
5.1.3 Traffic Limit Setting


Press the "F" key to enter key operation mode. The screen will display "SET C", prompting you to set or modify the instrument coefficient C. The original instrument coefficient value will be displayed first.

Press the "+1" key to increase the value, and press the ">" key to move the flashing value to the right by one digit. After setting or modifying the value, press the "F" key to confirm.
The message "C PASS" indicates that the C value has passed.

The display shows SET CUT and the original low-flow cutoff value, indicating that it can be set or modified.

Press the "+1" key or the ">" key to change the small flow cutoff value. After making the change, press the "F" key to confirm, and it will then be displayed.
CUT PASS indicates that the CUT value has passed.

Displaying FL¯¯ indicates that a data limit needs to be set. The existing FL¯¯ value will be shown first.

Press the "+1" key or the ">" key to change the data usage limit. After changing it, press the "F" key to confirm, and the following will be displayed.
FL¯ ¯ PASS indicates that the pass/fail signal is received.

The "End" option displays a blinking icon, indicating a request to confirm whether the operation is complete.

Press "F" and ">" keys simultaneously. Then press "F", "+1", and ">" keys simultaneously.
If the display shows 8 flashing zeros after a certain number of seconds, the three-key display will alternately show 2", 5", and 10". Press the "F" key alone to confirm the operation. When 2" is displayed, press the "F" key to end the operation and clear the accumulated amount. The display refresh cycle will then change to 2 seconds.

Operation complete, return to measurement status

Figure 5
After setting the low flow cutoff value, FLˉˉ will be displayed, indicating that the maximum flow value corresponding to the 20mA output needs to be entered. The setting method is the same as in 5.1.1. After setting, "End" will flash, indicating whether the key operation procedure is finished. If you press the "F" key to confirm, the instrument will store all parameters in the EEPROM and switch to normal measurement and display.
5.1.4 How to clear the accumulated total?
To prevent loss of accumulated data due to accidental operation or unnecessary intervention by others, several operational steps have been added. After pressing the "F" key to enter the key operation program, press the "F" key repeatedly until "End" flashes. Then, simultaneously press and hold the "F" key and the ">" key for more than 5 seconds. Eight flashing "0"s will appear, prompting you to confirm whether you want to clear the total amount. If you change your mind, press any key except "F" to exit the clearing operation. If you are sure you want to clear it, press the "F" key to confirm. After clearing the total amount, it is stored in the EEPROM and the normal measurement display is automatically restored.
Different display refresh cycles have no impact on measurement and integration accuracy.
5.2 Zeroing the Flow Meter at the Factory The flow meter is already zeroed at the factory and generally does not require adjustment. If there are significant changes in the field conditions, the sensor can be zeroed using the methods described below.
Turn on the instrument power, close the pipeline valve, and turn potentiometer W2 counterclockwise to the maximum. At this point, although there is no flow, the sensor will still have a slight output due to interference. Slowly turn W2 clockwise until there is just no output. Open the valve, and the instrument should work normally.
5.3 Adjustment of Output Current For ease of use and speed, a jumper switch (Figure 3 of 3) is installed on the lower right side of the front circuit board. During normal measurements, the jumper plug must be unplugged. When the jumper plug is plugged in, the instrument automatically generates a current signal corresponding to the lower flow limit (0) and the upper flow limit (i.e., the set FLˉˉ). If a 250-ohm precision resistor is connected in series in the output circuit (see Figure 4), a voltage alternating between 1 volt and 5 volts will be measured, with a cycle of approximately 20 seconds. The two potentiometers marked "4mA" and "20mA" on the rear circuit board can be adjusted repeatedly until the voltage is exactly the lower limit of 1 volt and the upper limit of 5 volts (i.e., the lower limit reaches 4 mA and the upper limit reaches 20 mA).
★After adjustment, be sure to unplug the jumper connector!
There is a set of jumper switches 10 on the top of the front circuit board for input signal selection. During operation, the jumper plug must be inserted into the "Measure" position on the left. If inserted into the "2KHZ" side, the instrument will automatically connect to the 2048Hz standard signal to replace the frequency signal of the vortex shear sensor for instrument inspection.
★Note: Make sure to plug the jumper cord back into the "test" position when working! Otherwise, you will not be able to take a measurement.
VI. Troubleshooting Fault: There is flow in the pipeline, but the flow rate display shows 0.
Troubleshooting Step 1: Confirm that there is indeed flow in the pipe, and that it is greater than the lower limit of measurable flow.
2. Check if the low-flow cutoff value is set too high.
3. If the pipeline flow is normal, adjust the potentiometer W2 on the circuit board according to the method in section 5.2. If there is output and display, it means that the operation is basically normal.
4. If there is still no output, insert the jumper switch (10) above the front circuit board to the right. If the flow rate is still 0 and the cumulative amount does not change, it indicates that there is a problem with the front circuit board and it should be replaced.
5. If the cumulative value increases regularly in test 4, the problem still lies with the rear circuit board or transmission.
Feeling grateful.
6. Determine if the sensor head is good or bad. Disconnect the two leads of the sensor head from the terminals at the bottom of the rear circuit board. Use a multimeter to measure the resistance of the two leads of the sensor head, as well as the resistance of each lead to the housing. Both should be greater than 2MΩ; otherwise, the sensor head needs to be replaced. If the sensor head is normal, then the rear circuit board needs to be replaced.
Fault: There is no flow in the pipeline, but the displayed value is changing. Troubleshooting steps: 1. Check if the instrument installation location is vibrating excessively. If the vibration is excessive, refer to step 3.2.
damping.
2. Turn potentiometer W2 clockwise until the amplifier just stops outputting, causing the flow display to return to zero.
Fault: The LCD screen refresh rate has increased dramatically. Troubleshooting steps: Power off and restart. If this does not work, repeat several times.

Fault: The LCD screen is dim and unclear. Troubleshooting steps: Turn off the device and restart it. If the problem persists, contact the manufacturer for assistance.
Fault: The light bar on the right side of the LCD screen alternates between fully bright and fully black, and the current output also fluctuates between maximum and minimum. Troubleshooting steps: This is because the jumper plug for current adjustment (Figure 3 of 3) is not unplugged. Unplug it.
This article is sourced from: Electromagnetic Flowmeter http://www.china-jtyb.com and Orifice Plate Flowmeter http://www.jsjhjt.net