Turbine flow meter features:

Installation and use of turbine flow meter

In order to give full play to the characteristics of the turbine flowmeter, full attention must be paid to the installation and use of the flowmeter. This aspect is briefly discussed below.
(1) Measured medium
The liquid measured by the turbine flowmeter is generally a low-viscosity (generally less than 15×l0-6m2/s), low-corrosive liquid. Although there are already turbine flowmeters for the measurement of various media, the measurement of high temperature, high viscosity and strong corrosive media still needs to be carefully considered and corresponding measures should be taken. When the medium viscosity v is greater than 15×l0-6m2/s, the meter coefficient of the flow meter must be calibrated in solid liquid, otherwise it will produce a large error.
Vapor-liquid two-phase flow, gas-solid two-phase flow and thick-solid two-phase flow can not be measured by turbine flowmeter.
(2) Requirements for pipe installation
The installation of the flowmeter has a great influence on the measuring accuracy of the flowmeter.
a. The uneven flow velocity distribution and the presence of secondary flow in the pipe are important factors affecting the measurement accuracy of turbine flowmeters. Therefore, the turbine flowmeter has certain requirements for the upper and downstream straight pipe sections. For industrial measurement, a straight pipe length of 10D upstream and 5D downstream is generally required. To eliminate secondary flow, a rectifier can be installed at the upstream end. If the upstream end can ensure that there is a straight pipe section of about 10D, and the rectifier is installed, the measurement accuracy of the flowmeter can reach the accuracy level of the calibration.
b. Turbine flowmeter has high requirements for the cleanliness of the fluid, and filters must be installed before the flowmeter to ensure the cleanliness of the fluid. Filter can be used funnel type, its own cleanliness, can measure the difference pressure changes at both ends.
c. In order to ensure that the liquid through the flowmeter is single-phase, that is, can not let air or steam into the flowmeter, the upstream of the flowmeter should be installed when necessary. For easily vaporized liquids, a certain back pressure must be guaranteed downstream of the flow meter. The size of the back pressure can be twice the pressure drop of the flow sensor at higher flow rates plus 1.2 times the vapor pressure of the liquid being measured at higher temperatures.
(3) Signal transmission line
In order to ensure that the display instrument has sufficient sensitivity to the pulse signal output by the turbine sensor, it is necessary to improve the signal-to-noise ratio. To this end, various electrical interference phenomena, namely electromagnetic induction, electrostatic and capacitive coupling, should be prevented during installation. Therefore, when configuring signal transmission lines, you must pay attention to the following points:
a. Limit the length of signal cables.
b. The signal transmission line should be shielded cable to prevent induced noise from outside. The transmission cable is required to be shielded and grounded at the display meter end. The transmission cable cannot be near the strong electromagnetic equipment, and it is not allowed to be arranged in line with the power line.
(4) Operation and maintenance
a. When the pipe of the turbine flowmeter needs to be cleaned, the bypass must be opened, and the cleaning liquid cannot pass through the flowmeter.
b. When the pipeline system is started, the bypass must be opened first to prevent a sudden increase in flow rate, causing damage to the turbine speed.
c. Turbine flowmeter bearings should be replaced regularly, and the wear of bearings can generally be observed according to the change of small flow characteristics.

If you want to know more about the flow meter or flow meter selection, please consult the Aister flow meter manufacturer email: sales@aistermeter.com for help.