Turbine flowmeters are sensitive to field conditions and users should try to meet its requirements in order to maintain factory accuracy. When the temperature and pressure of the fluid medium differ greatly from the reference conditions, the volume change of the sensor housing can be calculated based on the material of the sensor and the temperature pressure, and the meter reading can be corrected. When the viscosity of the fluid medium under working conditions is different from the viscosity of the calibration fluid, it should be corrected according to the viscosity correction curve provided by our company. Turbine flowmeters have certain requirements on the length of straight sections upstream and downstream of them, and they should be managed, especially when the user requires high accuracy. The meter shows the volumetric flow under the working conditions of the media. To know the standard volume flow or mass flow, density compensation is also required.
Turbine flowmeters have a reduced accuracy during use, which may be the reason for this:
1, the media generally have some impurities, the bearing, the shaft should wear, so that the gap between the two increases, the dynamic balance of the moving parts is destroyed, the speed is reduced, or dirt into the gap, so that the resistance to increase the movement , Speed ​​drops. All of these reasons cause the display value of the instrument to decrease, causing a negative error, which is detrimental to the fluid supplier.
2. The change of fluid temperature and pressure may cause the air contained in the pipeline to escape the air contained in the pipeline or the pressure in the pipeline to be lower than the saturated vapor pressure of the fluid to make part of the liquid into steam, or it may cause the outside pressure due to the negative pressure of the medium. The gas is sucked into the pipeline. These gases flow along with the measured fluid, causing the indicator value of the instrument to increase, causing a positive error, which is detrimental to the demand of the fluid.
3. The fibrous or viscous impurities in the fluid are attached to the rotating part of the flowmeter, which increases the rotational resistance, causing the indicator value of the instrument to decrease, causing negative errors, and adversely affecting the fluid supplier.
4, the working environment is rather harsh, for example, electromagnetic field interference, dust, high temperature, vibration, humidity, etc., may cause malfunction or failure of the turbine flow sensor, directly caused by the turbine flowmeter error, the error is positive or negative The value may not be obvious or it may completely fail. For the above phenomenon, when it is more serious, problems can be found in the comparison of the working status of the process, and it is easy to take corresponding measures. However, in the early stages of the problem, problems could not be discovered without special measures.
Based on the principle of turbine flowmeters and on-site work experience, we propose to add a pair of pressure measuring ports on the pipe wall of the upstream and downstream pipes of the flowmeter at the initial stage of installation of the turbine flowmeter and connect with the differential pressure gauge when necessary. In the working state, record the contrast between the indicated value of the flowmeter and the indicated value of the differential pressure gauge. If everything is normal at this time, consider the comparison relationship as the basis for checking whether the flowmeter works normally. For example, if you regularly measure this contrast relationship, if you find that the Flow Meter indication value is the same under the same differential pressure meter indication, you may suspect that the flowmeter has failed. When checking the flowmeter's sensor, the sender can be checked first. The method is to remove the sender separately, input a known signal and compare the output value to find the problem. If the fault cannot be eliminated for a short period of time, it can be replaced with a new one. If it is not its cause, the flowmeter should be unloaded from the process line and further carefully examined for symptomatic treatment. For dirty fluids or liquids that may produce gas, when installing a flowmeter, it can be installed with filters or air eliminators and gas collectors upstream to enhance routine maintenance work, regularly cleaning filters, eliminating air eliminators, The gas or debris in the collector ensures the normal operation of the flowmeter.
Turbine flowmeter
Turbine flowmeters have a reduced accuracy during use, which may be the reason for this:
1, the media generally have some impurities, the bearing, the shaft should wear, so that the gap between the two increases, the dynamic balance of the moving parts is destroyed, the speed is reduced, or dirt into the gap, so that the resistance to increase the movement , Speed ​​drops. All of these reasons cause the display value of the instrument to decrease, causing a negative error, which is detrimental to the fluid supplier.
2. The change of fluid temperature and pressure may cause the air contained in the pipeline to escape the air contained in the pipeline or the pressure in the pipeline to be lower than the saturated vapor pressure of the fluid to make part of the liquid into steam, or it may cause the outside pressure due to the negative pressure of the medium. The gas is sucked into the pipeline. These gases flow along with the measured fluid, causing the indicator value of the instrument to increase, causing a positive error, which is detrimental to the demand of the fluid.
3. The fibrous or viscous impurities in the fluid are attached to the rotating part of the flowmeter, which increases the rotational resistance, causing the indicator value of the instrument to decrease, causing negative errors, and adversely affecting the fluid supplier.
4, the working environment is rather harsh, for example, electromagnetic field interference, dust, high temperature, vibration, humidity, etc., may cause malfunction or failure of the turbine flow sensor, directly caused by the turbine flowmeter error, the error is positive or negative The value may not be obvious or it may completely fail. For the above phenomenon, when it is more serious, problems can be found in the comparison of the working status of the process, and it is easy to take corresponding measures. However, in the early stages of the problem, problems could not be discovered without special measures.
Based on the principle of turbine flowmeters and on-site work experience, we propose to add a pair of pressure measuring ports on the pipe wall of the upstream and downstream pipes of the flowmeter at the initial stage of installation of the turbine flowmeter and connect with the differential pressure gauge when necessary. In the working state, record the contrast between the indicated value of the flowmeter and the indicated value of the differential pressure gauge. If everything is normal at this time, consider the comparison relationship as the basis for checking whether the flowmeter works normally. For example, if you regularly measure this contrast relationship, if you find that the Flow Meter indication value is the same under the same differential pressure meter indication, you may suspect that the flowmeter has failed. When checking the flowmeter's sensor, the sender can be checked first. The method is to remove the sender separately, input a known signal and compare the output value to find the problem. If the fault cannot be eliminated for a short period of time, it can be replaced with a new one. If it is not its cause, the flowmeter should be unloaded from the process line and further carefully examined for symptomatic treatment. For dirty fluids or liquids that may produce gas, when installing a flowmeter, it can be installed with filters or air eliminators and gas collectors upstream to enhance routine maintenance work, regularly cleaning filters, eliminating air eliminators, The gas or debris in the collector ensures the normal operation of the flowmeter.
Turbine flowmeter
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