Common Faults of Gas Turbine Flowmeter and Handling Methods

The gas turbine flowmeter is the advanced ultra-low power consumption single-chip microcomputer technology developed by the turbine flow sensor and displays the accumulation of new integrated intelligent instruments. It uses a double row of liquid crystal field displays. It has a compact mechanism, intuitive and precise readings, high reliability, no external power interference, lightning resistance, low cost, and other obvious advantages. The high-definition LCD can simultaneously show the instantaneous flow rate (4 effective digits) and the accumulated flow rate (8 effective numbers with clear function). This type of turbine flowmeter are explosion-proof product, and the explosion-proof level is ExdIIBT6.

In the use process, gas turbine flow meters will inevitably encounter some common faults. For these faults, flowmeter manufacturer BCST offers you a series of solutions.

Fault phenomenon 1: there is a flow-through, but the gas turbine flow meter instantaneous flow is zero.

Fault analysis and solution：

1. A wiring error occurred. We need to check the gas turbine flowmeter wiring.
2. 2. This may be because the internal parameters of the gas turbine flow meter have been changed. We need to test the meter parameters with the calibration certificate.
3. The signal acquisition coil is damaged, affecting signal transmission. It means that the signal cannot be transmitted to the converter even if it is flowing. Instead, we need to slide the outer wall of the signal acquisition coil with a magnetic screwdriver. If there is still no flow indication, the signal acquisition coil is damaged.
4. The media is too dirty, and the filter is blocked.
5. The impeller may have jammed. We need to check the impeller.

Treatment measures：

We need to clean or replace the internal turbine filter regularly.

We need to check if there is a large amount of foreign matter inside. In severe cases, we need to replace the turbine blades.

Fault phenomenon 2: The gas turbine flowmeter has an instantaneous flow display when no flow is passed.

Fault analysis and solution：

1.  There is violent vibration in the pipeline. Therefore, we recommend adding vibration damping measures.
2. The flowmeter is not well grounded. So we need to check the grounding in advance. Please see.
3. There is magnetic interference at the site—for example, frequency converters, motors, solenoid valves, etc. And the site 50Hz above the industrial frequency interference to a certain degree may affect the use of the meter. The formula for calculating industrial frequency interference is Q=3600k f/k,f=50Hz, and k=coefficient of the instrument. This calculation can determine whether the instrument is subject to industrial frequency interference. If there is, we recommend replacing the installation location.
4. The pipeline shut-off valve of the flowmeter is not entirely closed. Therefore, we need to check the valve thoroughly.
5. Install evoke sensitivity is too high, or trigger level is too low.

Treatment methods：

1. We need to improve the instrument grounding and signal line shielding contact
2. We need to install away from the source of interference and take isolation measures
3. We need to reduce the sensitivity or increase the trigger level
4. We need to take damping measures, e.g., by using SSP (DSP) function amplifiers

Fault phenomenon 3: The gas turbine flowmeter can be 

measured commonly, but the value is inaccurate.

Failure analysis and solution：

1. The internal parameters of the gas turbine flowmeter are faulty. Therefore, we need to test the instrument parameters following the calibration certificate.
2. The instrument pressure display is abnormal. Therefore, we need to check the pipeline pressure.
3. After this situation, it is most likely because of the turbine machine’s internal circuit problems. For example, the circuit nodes are disconnected, the signal line solder joints are not up to standard, and the circuit board has poor contact and other problems. It may also be due to the turbine blades being obstructed by a large substance.

Treatment measures：

We need to check the circuits that are prone to poor contact. If no such problems are found, the turbine circuit board needs to be replaced. In addition, the turbine blades need to be regularly maintained and debris removed.

Fault phenomenon 4: There is no flow signal output of the gas turbine flow meter.

Failure analysis：

1. The instrument is not energized
2. The signal line is disconnected
3. The power supply of the signal amplifier board is not normal
4. The amplification board is not working properly
5. The probe sensor is not working properly
6. There is no flow in the pipe, or the flow is too small

Treatment method：

1. We need to check the power supply of the instrument to ensure that the external power supply is sent to the signal converter
2. We need to check the signal output of the amplifier board. If the signal output of the amplifier board is standard, the signal line is broken. At this point, we need to check the processing.
3. If the external power supply is regular, we should check the working power supply of the amplifier board circuit. If it is not normal, we should check the power supply device and deal with it.
4. We need to check the working status of the amplifier board at all levels starting from the front stage, and deal with it.
5. We need to check the sensor and deal with it.

Fault phenomenon 5: The output signal of the gas turbine flowmeter is unstable.

Failure analysis：

1. The flow is working at the lower or upper limit state
2. The amplification board is not adjusted correctly.
3. The sensor is damaged, or the lead contact is poor
4. The instrument is poorly grounded or has electromagnetic solid field interference
5. The pipeline vibration is strong
6. There are foreign objects or protrusions in the pipeline. It destroys the media flow state or vortex signal separation state. Mainly refers to the protrusion of the instrument gasket. There are also sensors installed in different centers caused by protrusion. As a result, pipeline and instrument caliber differences are too large, caused by the protrusion, installation residues, other installation protrusions, etc.
7. The fluid state does not meet the flowmeter technical conditions. It includes the flowmeter before and after the valve open state disturbance, fluid formation of two-phase flow, or the existence of cavitation phenomenon.

Treatment methods：

1. We need to change the process parameters or replace the flowmeter so that it works in the ‘normal measurement range
2. We need to re-adjust the sensitivity of the put too plate
3. We need to check the processing or replace the sensor
4. We need to improve the earthing and install it away from sources of interference
5. We need to take vibration damping measures in the pipeline
6. We need to check and remove foreign objects
7. We need to change the installation state to meet the technical conditions.

Fault phenomenon 6: The gas turbine flowmeter measurement error is large.

Failure analysis：

1. 1. The instrument error is large. It mainly refers to the meter over the calibration cycle meter coefficient change error. There are also sensor sticky or damage errors and analog signal output meter zero signal drift or range adjustment error.
2. The instrument is not selected correctly.
3. The supporting instrumentation error is large or not working correctly. It includes the supporting instrument error, supporting the instrument installation error caused by unreasonable and the choice of compensation method is not suitable for the error caused by
4. The installation conditions of the instrument do not meet the requirements of the technical conditions of the device.
5. The flow state of the fluid in the pipeline does not meet the requirements of the measurement conditions.

Treatment methods：

1. We need to check and calibrate the instrument
2. We may need to select a new instrument type
3. We need to check and calibrate the matching instrument and correct the installation, and use
4. We have to re-install the instrument to make it meet the requirements
5. We have to re-install and re-adjustthem.