Rotor Flowmeter Installation

1. The rotameter must be vertically installed on the pipe without vibration. The fluid flows through the flowmeter from bottom to top, and the perpendicularity is better than 2 °, and the horizontal angle is better than 2 ° during horizontal installation; (Now there is a rotor flowmeter that can be installed horizontally).

2. In order to facilitate the maintenance and replacement of the flowmeter and the cleaning of the measuring pipeline, the metal tube float flowmeter installed on the processing pipeline shall be equipped with a bypass pipeline and bypass valve.

3. The inlet of the rotameter shall have a straight pipe section of more than 5 times the length of the pipe diameter, and the outlet shall have a 250mm straight pipe section.

4. If the medium contains ferromagnetic substances, a magnetic filter shall be installed; If the medium contains solid impurities, a filter shall be installed between the valve and the straight pipe section.

5. When used for gas measurement, ensure that the pipeline pressure is not less than 5 times the pressure loss of the flowmeter so that the float can work stably.

6. In order to avoid the deformation of the flowmeter caused by the pipeline, the flange of the processing pipeline must be coaxial and parallel to the flange of the flowmeter. The pipeline is supported to avoid pipeline vibration and reduce the axial load of the flowmeter. The control valve in the measurement system should be installed downstream of the flowmeter.

7. When measuring the gas, if the gas is directly discharged to the atmosphere at the outlet of the flowmeter, a valve should be installed at the outlet of the instrument, otherwise, the pressure drop at the float will cause data distortion.

8. When installing PTFE lined instruments, do not tighten the flange nuts asymmetrically to avoid deformation of PTFE lining.

9. For instruments with LCD display, try to avoid direct sunlight on the display to avoid reducing the service life of LCD; For instruments with lithium battery power supply, try to avoid direct sunlight and high-temperature environment (≥ 65 ℃) to avoid reducing the capacity and life of lithium battery.

Attention to rotameter selection

1. For the selection of remote output metal tube float rotameter, select the rotameter suitable for the explosion-proof type requirements of the site; During installation, attention shall also be paid to the fastening of the shell and the sealing of the wiring port after the instrument is powered on to meet the requirements of explosion-proof, protective and anti-corrosion.

2. For places where the temperature of the measured medium is too high (>120 ℃) or too low, heat preservation or insulation measures shall be taken for the sensor part of the rotameter. In order to ensure the ambient temperature for the normal operation of the signal converter indicator, the high-temperature indicator shall be selected.

3. For some measured medium requiring thermal insulation or cooling, a jacket-type rotameter shall be selected. The heat tracing or cooling interface of the standard metal tube float rotameter shall be connected with the DIN2501 DN15 PN1.6 flange. If another flange or threaded connection is required, please indicate when ordering.

4. For unstable pressure of medium at the inlet of the rotameter, especially for gas measurement, a damping structure shall be selected to ensure accuracy and service life.

5. If the pressure level required by the medium is higher than the standard pressure level, please select the high-pressure structure when selecting the model, and the high-pressure type adopts HG20595-97 RF neck butt welding steel pipe flange. If other standards are adopted, please indicate when ordering.

6. During the installation of the rotameter, ensure that the perpendicularity of the measuring pipe is better than 5%, and install a bypass to facilitate maintenance and cleaning without affecting production.

7. The installation position of the rotameter shall ensure that there is a straight pipe section ≥ 5DN at the inlet and a straight pipe section ≤ 250mm at the outlet; If the medium contains ferromagnetic substances, a magnetic filter shall be installed in front of the rotameter.

8. The control valve in the measurement and control system shall be installed downstream of the rotameter. When used for gas measurement, ensure that the working pressure is not less than 5 times the pressure loss of the rotameter, so that the rotameter can work stably.

9. Before installing the metal tube float rotameter, the welding slag in the pipe shall be purged; Take out the stop element in the rotameter during installation; After installation, open the control valve slowly to avoid damaging the rotameter.

Troubleshooting

The rotameter has the characteristics of a simple structure, reliable operation, wide application range, accurate measurement, convenient installation, etc., and is resistant to high temperature and high pressure. How to eliminate the following common faults in the operation of a flowmeter?

No current output

1. First check whether the wiring is correct.

2. Whether the LCD has a display. If there is a display and no output, most of the output tubes are damaged, and the circuit board needs to be replaced.

3. The calibration value is lost. Due to E2PROM failure, the calibration data of the instrument will be lost, there will be no output current, and the current will remain unchanged. Solution: The data recovery operation can be used. If it does not work, you can first set the data in password 2000, and then set the data in password 4011. The method is to manually push the pointer to calibrate the data from RP to 100%.

 No field display

1. Check whether the wiring is correct.
2. Check whether the power supply is correct.
3. Reinstall the LCD module and check the contact.
4. For multi-wire power supply mode, check whether terminals 12 and 13 are connected to an ammeter or short-circuited.

 Incorrect alarm

1. Check that the deviation setting d value cannot be too large.
2. Whether the logic function is correct in the FUN function. HA-A represents upper limit positive logic. LA-A represents lower limit positive logic.
3. Check the setting size of the alarm value in SU.
4. If the LCD barcode indicates correctly and the output does not act, check whether the external power supply and the negative pole of the external power supply are connected to the negative pole of the instrument power supply.

Rotary flowmeter pointer jitters:

1. Slight pointer jitter: generally caused by medium fluctuation. It can be overcome by increasing damping.
2. Moderate pointer jitter: generally caused by the media flow. Gas is generally caused by unstable medium operating pressure. The pressure stabilizing or current stabilizing device can be used to overcome or increase the air damping of the float flowmeter.
3. Sharp pointer jitter: the float flowmeter is out of range due to medium pulsation, unstable air pressure, or inconsistency between the pressure, temperature, and flow of the gas operation state given by the user and the actual state of the float flowmeter.

The pointer of the float flowmeter stops at a certain position

The main reason is that the float of the float flowmeter is stuck.
Generally, the valve of the float flowmeter is opened too fast when it is used, which makes the floating impact the stopper rapidly upward, causing the stopper deformation and locking the float. However, it does not rule out that the float is stuck due to the misalignment between the float guide rod and the stop ring. During processing, the instrument can be disassembled, the deformed stopper can be removed for shaping, and whether it is concentric with the guide rod can be checked. If it is not concentric, it can be corrected, and then the float can be installed, and the float can be pushed by hand to feel that the float is unobstructed up and down. In addition, the float flowmeter must be installed vertically or horizontally, without tilting, otherwise, it is easy to cause the meter to be stuck and bring errors in the measurement.

 Large measurement error of float flowmeter

1. The installation does not meet the requirements
For vertical installation, the float flowmeter shall be vertical, and the inclination shall not be greater than 20 degrees
For horizontal installation, the float flowmeter shall be kept horizontal and the inclination shall not be greater than 20 degrees
There shall be no ferromagnetic objects in the 100mm space around the float flowmeter.
The installation position shall be far away from the valve-reducing port, pump outlet, process pipeline turning port, etc. The requirements for a 250mm straight pipe section after the first 5D shall be maintained.

2. The large change in the density of the liquid medium is also a reason for the large error. 

Before calibration, the instrument will convert the medium according to the density given by the user, and convert it to the water flow in the calibration state for calibration. Therefore, if the medium density changes greatly, it will cause great errors in the measurement. The solution can be to take the changed medium density into the formula and convert it into an error correction coefficient and then convert the flow measured by the flowmeter by multiplying the coefficient into the real flow.

3. As the gas medium is greatly affected by temperature and pressure, it is recommended to use temperature and pressure compensation to obtain the true flow.

4. Due to long-term use, pipeline vibration, and other factors, the magnetic steel, pointer, counterweight, rotating magnetic steel, and other moving parts of the float flowmeter are loose, resulting in large errors. Solution: It can be verified by pushing the pointer manually first. First, press the pointer at the RP position to see whether the output is 4mA and the flow display is 0%, and then verify according to the scale. In case of any discrepancy, the position of the components can be adjusted. Professional personnel is generally required to adjust, otherwise, the position will be lost, and it is required to return to the manufacturer for correction.

Incorrect cumulative pulse output

1. Check whether the alarm value of the selected cumulative pulse output is set to zero.
2. If the circuit board fails, replace it.
8、 On-site liquid crystal of metal rotameter displays 0 or full range
1. Check the range and zero parameters set in the 2000 password. ZERO must be less than SPAN, and the two values cannot be equal.
2. Check whether the sampling data comes up. Push the pointer manually to see the change in the sampling value. If there is no change, it is generally the fault of the sampling circuit of the circuit board, and the circuit board needs to be replaced.
3. If the circuit board fails, replace it.