Common Fault Analysis of vortex flowmeter
Author:vacorda Source:vacorda.com Date: 2017-01-04 15:38:24
1. Indicator has no display
1.1 New factory instrument:
- During the transportation, the power plug (or wire) is loose or has bad contact;
- Observe the LCD screen is damaged (writing defects or liquid crystal cracks);
- Poor contact between the circuit boards. (Try pressing the circuit board)
- Quality problems of the circuit board device.
1.2 For used instruments:
- Check the power
If battery-powered, then check the whether the battery working, use the multimeter to detect the voltage, it is considered normal when it more than 2.1v for B, C ,M ,S head, but for D type head, it will need more than 3v; If it is 24V power supply, check whether the 24V line is used too long, led to the line aging touch virtual, or 24V output voltage is low, need to take a multimeter to detect whether the voltage is 24V.
- Considering the site spot
a. Whether the site humidity is relatively large;
b. Ambient temperature is relatively high (more than 55 ° C or more)
c. Whether there is water signs of the meter head
d. Lightning strike
e.Circuit board burned out (voltage instability, or power supply short-circuit)
2. When the flow through, there are no transient and cumulative display
2.1. For M, D-type vortex flowmeter, can check the probe whether it has the frequency input.
2.2. To determine whether the internal parameters or dial code has been changed.
2.3. Test whether the signal into circuit board, remove the instrument, use a tool to tap the probe, or tap the vortex directly to see if there are displays.(Constant pressure compensation D-type vortex test saturated steam algorithm, superheated steam algorithm or the standard case of gas pressure is 0, the general number of knocking out the number of parameters required to change the algorithm to conventional gas algorithm or see the attached screen to see the frequency )
2.4. Whether the amount of the traffic is too low, in the lower limit or lower, it may be lower than the lower limit value.
2.5. Whether the media has too much impurities, or the body or probe will be covered.
2.6. check whether there are resistance and insulation of the probe. Resistance should ≥20megohms between the probe, the insulation is infinite.(When considering, the converter section is usually considered whether the normal signal acquisition, then consider the probe problem)
3. There are flow display but actually no flow
- Sensitivity, amplification is too high (usually dial 5 or 6).
- Pipe vibration.
- Magnetic interference (frequency interference, Q = f / k * 3600 can be considered about whether the same with the display value)
- Whether the site valve is closed.
- The pipeline pressure pulsation.
(Factory vortex flow meter)
4. The inaccuracy of the flow display
- Whether the internal parameter is changed;
- The flow is below the low limit or exceed the up limit;
- Whether the temperature and pressure are normal(temperature and pressure compensation type);
- Whether the installation is reasonable.
5. Vortex flowmeter display fluctuations
- There may be interference (power frequency interference, Q = f / k * 3600 can be considered whether the same with the display value).
- Installation (whether the before and after the straight pipe can meet the demand), the medium situation (whether the pure liquid or gaseous), whether the instrument is effectively grounded.
- The instrument itself dials whether the modulation is too high. (Sensitivity, magnification)
- Whether the internal parameters of the instrument has been adjusted.
- The air supply causes fluid pulsation (for air measurement, such as Roots blowers, reciprocating compressors)