Turbine flow meter selection
Turbine flowmeter has become one of the indispensable measuring instruments, turbine flowmeter selection, need to pay attention to the following points.
The selection of turbine flowmeter should be considered from the following aspects:
1, accuracy level: Generally speaking, the selection of turbine flowmeter is mainly due to its high precision, but the higher the accuracy of the flowmeter, the more sensitive to changes in the field conditions of use, so the choice of instrument accuracy should be careful, from the economic point of view. For the trade settlement instrument of the large-caliber gas transmission pipeline, it is cost-effective to invest more in the instrument, and for the occasion of small throughput, the medium precision level can be selected.
2, flow range: the choice of flow range of the turbine flowmeter has a greater impact on its accuracy and service life, and each caliber of the flowmeter has a certain measurement range, the choice of flowmeter caliber is also determined by the flow range. The principle of selecting the flow range is that the minimum flow rate in use shall not be lower than the minimum flow rate allowed by the instrument, and the maximum flow rate in use shall not be higher than the maximum flow rate allowed by the instrument. For the daily actual operation time of the instrument is not more than 8 hours, choose 1.3 times of the actual use of the maximum flow as the upper limit of the flow range, for the daily actual operation time of the instrument is not less than 8 hours, choose 1.4 times of the actual use of the maximum flow as the upper limit of the flow range. The lower limit flow rate of the instrument should be 0.8 times of the actual minimum flow rate.
3, the density of gas: the impact on the gas turbine flowmeter and fluid physical properties is mainly the gas density, which has a greater impact on the instrument coefficient, and is mainly in the low flow area. If the gas density changes frequently, the flow coefficient of the flowmeter should be corrected.
4, pressure loss: try to choose a small pressure loss turbine flowmeter. Because the pressure loss of the fluid through the turbine flow meter is smaller, the energy consumed by the fluid from the input to the output pipeline is less, that is, the total power required will be reduced, which can greatly save energy, reduce transmission costs, and improve utilization.
5, structure type: (1) The internal structure should choose the reverse thrust turbine flowmeter. Because the reverse thrust structure can make the impeller in a floating state within a certain flow range, there is no contact point in the axial direction, and there is no end friction and wear, which can extend the service life of the bearing. (2) According to the type selection of pipeline connection, the flow meter has two ways of horizontal and vertical installation, and the horizontal installation and pipeline connection have flange connection, thread connection and clamp connection. Flange connection is selected for medium diameter, thread connection is selected for small diameter and high pressure pipe, clamp connection is only suitable for low pressure small diameter pipe, vertical installation is only threaded connection. (3) Selection according to environmental conditions, considering the influence of temperature and humidity. Natural gas metering should choose the intrinsically safe explosion-proof turbine flowmeter.
6, bearings: turbine flow meter bearings generally have tungsten carbide, polytetrafluoroethylene, carbon graphite three types of materials. Natural gas meter bearings should be made of tungsten carbide.
The above is the turbine flow meter selection points, if you have other questions about the turbine flow meter selection, you can contact Aister instrument at any time, Aister instrument will choose a suitable turbine flow meter for you to use.
