Gas turbine flowmeter selection_gas turbine flowmeter application

　　Gas Turbine Flow Meter Selection

　　In order to ensure the correct measurement of the gas turbine flowmeter, we need to make the correct selection as a prerequisite. Only by providing the correct and appropriate field parameters and making appropriate selection can the accuracy of the natural gas turbine flowmeter be guaranteed. We can start from the following aspects.

　　First, accuracy level: Generally speaking, turbine flowmeters are selected mainly for their high accuracy, but the higher the accuracy of the flowmeter, the more sensitive it is to changes in on-site conditions. Therefore, the accuracy of the meter should be carefully selected and should be considered from an economic perspective. For trade settlement instruments for large-diameter gas pipelines, it is cost-effective to invest more in the instrument, while for occasions with small transmission volumes, medium-precision instruments can be selected.

　　Second, the selection of the flow range of the turbine flowmeter has a great influence on its accuracy and service life, and each caliber of flowmeter has a certain measurement range, and the selection of the flowmeter caliber is also determined by the flow range. The principle of selecting the flow range is: the smaller flow rate during use shall not be lower than the smaller flow rate allowed to be measured by the instrument, and the larger flow rate during use shall not be higher than the larger flow rate allowed to be measured by the instrument. For intermittent working occasions where the actual operation time of the instrument does not exceed 8 hours per day, 1.3 times the actual larger flow rate during use is selected as the upper limit of the flow range; for continuous working occasions where the actual operation time of the instrument is not less than 8 hours per day, 1.4 times the actual larger flow rate during use is selected as the upper limit of the flow range. The lower limit flow of the instrument is 0.8 times the actual smaller flow rate.

　　Third, structural type: (1) The internal structure should use a reverse thrust turbine flowmeter. Because the reverse thrust structure can keep the impeller in a floating state within a certain flow range, there is no contact point in the axial direction, no end face friction and wear, and the service life of the bearing can be extended. (2) Select according to the pipeline connection method. The flowmeter has two installation methods: horizontal and vertical. The horizontal installation and pipeline connection methods include flange connection, threaded connection and clamp connection. Flange connection is used for medium diameter; threaded connection is used for small diameter and high pressure pipelines; clamp connection is only suitable for low pressure and small diameter pipes; vertical installation has only threaded connection. (3) Select according to environmental conditions, considering the influence of temperature and humidity.

　　Advantages and disadvantages of gas turbine flowmeter

　　shortcoming:

　　It cannot maintain calibration characteristics for a long time and needs regular calibration; it has high requirements for medium cleanliness (filters can be installed); the flow meter is greatly affected by the flow velocity distribution (flow regulators can be installed). With the continuous improvement of technology, its shortcomings are being continuously improved and solved by people through technical means.

　　advantage:

　　High measurement accuracy, good reproducibility and stability, wide measuring range, good linearity, high pressure resistance, small pressure loss; strong anti-interference ability, convenient signal transmission; simple structure, easy installation and maintenance; if a failure occurs, it will not affect the pipeline medium transportation. Good corrosion resistance.

　　Gas turbine flowmeter applications

　　Due to its numerous advantages, flow meters are widely used in trade settlement of crude oil, natural gas and valuable fluids. They can also be used in product production process control as a provider and controller of feedback signals for the control system.

　　Due to its good repeatability and reproducibility, it can be used as a standard flowmeter for standard flow calibration devices, or as a standard meter for period verification of flow standard devices. Turbine flowmeters are often used as transfer standards for international and domestic quality comparisons. Its main applications are summarized as follows: trade measurement, natural gas transmission and distribution pipelines, urban gas, etc.; process control, petrochemical, electric power, industrial boilers, etc.; standard meters for standard devices usually require an accuracy level of no less than 0.2.