The main directions for selecting gas turbine flowmeters

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This post was last edited by vn4893 on 2016-10-27 17:50 Gas turbine flowmeter is a new generation of high-precision and high-reliability gas precision metering instrument. It has excellent low-pressure and high-pressure metering performance, multiple signal output modes and low sensitivity to fluid disturbance. It has been widely used in the measurement of natural gas, coal gas, liquefied gas, light hydrocarbon gas and other gases. There are several particularly important factors that need to be paid attention to during the selection stage of gas turbine flow meters. Because they are related to the measurement effect and stable operation, they cannot be sloppy. Only when the selected instrument best matches the measured working conditions can the stable use of the instrument put into production be ensured and production efficiency improved. 　　1. The following are the key aspects of gas turbine flowmeter selection summarized by me for your reference and discussion.: 　　1. Accuracy level: Generally speaking, the main reason for choosing a turbine flowmeter is its high accuracy. However, the higher the accuracy of the flowmeter, the more sensitive it will be to changes in on-site usage conditions. Therefore, the accuracy of the meter must be selected carefully and from an economic perspective. For trade settlement instruments for large-diameter gas pipelines, it is cost-effective to invest more in the instrument, and for occasions where the transmission volume is not large, a medium-level accuracy can be used. 　　2. Flow range: The selection of the flow range of the turbine flowmeter has a great impact on its accuracy and service life, and each caliber of flow meter has a certain measurement range. The selection of the flow meter caliber is also determined by the flow range. The principle for selecting the flow range is: The minimum flow rate during use shall not be lower than the minimum flow rate allowed to be measured by the meter, and the maximum flow rate during use shall not be higher than the maximum flow rate allowed to be measured by the meter. For intermittent working situations where the actual operating time of the instrument does not exceed 8 hours per day, select 1.3 times the maximum flow rate during actual use as the upper limit of the flow range; for continuous working situations where the actual operating time of the instrument does not exceed 8 hours per day, select 1.4 times the maximum flow rate during actual use as the upper limit of the flow range. The lower limit flow rate of the instrument is appropriately 0.8 times the actual minimum flow rate. 　　3. Density of gas: For gas turbine flowmeters, the main impact of fluid physical properties is gas density, which has a greater impact on the instrument coefficient, mainly in the low flow area. If the gas density changes frequently, corrective measures should be taken to the flow coefficient of the flow meter. 　　4. Pressure loss: Try to use a turbine flowmeter with a small pressure loss. Because the smaller the pressure loss of the fluid passing through the turbine flowmeter, the less energy is consumed by the fluid from the input to the output pipe, that is, the total power required will be reduced, which can * * Save energy, reduce transportation costs, and improve utilization. 　　Someone has done experiments and found that the main component that affects the pressure loss is the front diffuser of the turbine flowmeter. Compared with the cone-shaped front diffuser, the pressure loss of the turbine flowmeter can be greatly reduced by using a semi-ellipsoid front diffuser. 　　5. Structural type: (1) The internal structure should be a reverse thrust turbine flowmeter. Because the reverse thrust structure can keep the impeller in a floating state within a certain flow range, there are no contact points in the axial direction, and there is no end face friction and wear, which can extend the service life of the bearing. (2) Select according to the pipe connection method. The flowmeter has two ways of installation: horizontal and vertical. The horizontal installation and pipe connection methods include flange connection, threaded connection and clamping connection. Flange connections are used for medium diameters; threaded connections are used for small diameter and high-pressure pipes; clamped connections are only suitable for low-pressure and medium-sized pipes; only threaded connections are available for vertical installation. (3) Select according to environmental conditions and consider the effects of temperature and humidity. For natural gas measurement, intrinsically safe explosion-proof turbine flowmeters should be selected. 　　6. Bearings: The bearings of turbine flowmeters are generally made of three types of materials: tungsten carbide, polytetrafluoroethylene, and carbon graphite. Natural gas meter bearings should be made of tungsten carbide material. 　　The above are the main aspects to consider when selecting. Due to the wide variety of turbine flowmeter types and specifications, especially the differences in product quality between different manufacturers, you should try your best to collect relevant technical standards and other information about the manufacturer and product when selecting a model, and make a decision after repeated investigations and comparisons. Everyone is welcome to actively discuss rumors.