Common faults and maintenance of metal tube rotor flowmeter

With the development of technology, and due to the characteristics of simple structure, reliable operation, wide applicability, accurate measurement, and easy installation, the use of metal rotor flowmeters is becoming increasingly widespread. But there may also be some malfunctions in daily use, which can be very troublesome. The editor will briefly introduce the common faults of metal tube rotor flow meters, hoping to bring help to everyone's work.

1、 The measurement error of the float flowmeter is large

1. If the installation does not meet the requirements, the float flowmeter should be installed vertically and the inclination angle should not exceed 20 degrees. For horizontal installation of float flow meters, they should be kept horizontal with an inclination angle of no more than 20 degrees. There should be no ferromagnetic objects in the 100mm space around the float flowmeter. The installation position should be far away from valve reducers, pump outlets, process pipeline bends, etc. Maintain the requirement of a straight pipe section of 250mm after the first 5D.

The significant variation in density of liquid media is also one of the reasons for the large errors. Due to the fact that the instrument converts the medium density given by the user into the flow rate of water in the calibration state before calibration, if the medium density changes significantly, it will cause significant measurement errors. The solution is to input the changed medium density into the formula, convert it into an error correction factor, and then multiply the flow rate measured by the flowmeter by the factor to obtain the actual flow rate.

3. Due to the significant influence of temperature and pressure on gas media, it is recommended to use temperature and pressure compensation to obtain the true flow rate.

4. Due to long-term use and various factors such as pipeline vibration, the sensing magnetic steel, pointer, counterweight, rotating magnetic steel and other moving parts of the float flowmeter become loose, resulting in significant errors. Solution: You can first verify by manually pushing the pointer. Firstly, press the pointer at the RP position to check if the output is 4mA and if the flow display is 0%. Then, verify according to the scale in sequence. If any discrepancies are found, the position of the components can be adjusted. Generally, professional personnel are required to make adjustments, otherwise it may cause position loss and require returning to the manufacturer for calibration.

2、 No current output

Firstly, check if the wiring is correct.

2. Does the LCD display? If there is no output, it is mostly due to a broken output tube and the circuit board needs to be replaced.

3. Loss of calibration values. Due to E2PROM malfunction, the instrument calibration data is lost, which can also cause no output current, and the current will remain unchanged. Solution: 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 calibrate the data from RP to.

3、 Float flowmeter pointer shaking:

1. Slight pointer shaking: usually caused by fluctuations in the medium. Increasing damping can be used to overcome it.

2. Moderate pointer shaking: usually caused by the flow state of the medium. For gases, it is generally caused by unstable operating pressure of the medium. Voltage stabilizing or current stabilizing devices can be used to overcome or increase the air damping of the float flowmeter.

3. Severe pointer shaking: Mainly due to medium pulsation, unstable air pressure, or the pressure, temperature, and flow rate of the gas operation state provided by the user not matching the actual state of the float flowmeter, resulting in significant differences and causing the float flowmeter to exceed its range.

4、 The pointer of the float flowmeter stops at a certain position and does not move

The main reason is that the float of the float flowmeter is stuck.

Generally, when using a float flowmeter, the valve is opened too quickly, causing the float to quickly impact the stopper upwards, causing deformation of the stopper and locking the float. But it cannot be ruled out that the float may get stuck due to the lack of concentricity between the float guide rod and the stop ring. When handling, the instrument can be removed, the deformed stopper can be removed and shaped, and the concentricity with the guide rod can be checked. If it is not concentric, it can be corrected. Then, the float can be installed and pushed by hand, feeling that the float is unobstructed up and down. In addition, when installing the float flowmeter, it must be installed vertically or horizontally, not tilted, otherwise it may cause the meter to jam and bring measurement errors.

5、 On site LCD display shows 0 or full range

1. Check the range and zero parameters set in the 2000 password. ZERO is required to be less than the value of SPAN, and the two values cannot be equal.
2. Check if the sampling data is up, and use your hand to push the pointer to see if the sampling value changes. If there is no change, it is generally a fault in the sampling circuit of the circuit board and the circuit board needs to be replaced.
6、 Incorrect alarm
1. Check that the deviation setting d value is not too large.
Is the logic function correct in the FUN function. HA-A represents upper limit positive logic. LA-A represents lower bound positive logic.

3. Check the alarm value setting size in SU.
If the LCD barcode indicates correctly and there is no action in the output, you can check whether the external power supply and the negative terminal of the external power supply are connected to the negative terminal of the instrument power supply.
5. Circuit board failure, replace the circuit board.

7、 Accumulated pulse output incorrect
1. Check if the alarm value for the selected cumulative pulse output is set to zero.

2. Circuit board failure, replace the circuit board.

8、 No on-site display
1. Check if the wiring is correct.
2. Check if the power supply is correct.
3. Reinstall the LCD module and check for loose contact.
4. For multi wire power supply mode, check whether terminals 12 and 13 are connected to an ammeter or short circuited.

Understanding the common faults of metal rotor flow meters can help us prepare for them. I hope this article has been helpful in helping you understand metal rotor flow meters.