Parameter selection of gas turbine flowmeter

Project Overview

The gas turbine flowmeter is a precision flow measurement instrument that can be used to measure the flow rate and total volume of liquid when matched with the corresponding flow totalizing instrument. Gas turbine flow meters are widely used in measurement and control systems in petroleum, chemical industry, metallurgy, scientific research and other fields. Gas turbine flowmeters equipped with sanitary connections can be used in the pharmaceutical industry.

First examine the given traffic range to see if it is reasonable. Whether a given large flow rate exceeds the design specification for a pipe of this diameter may correspond to whether the flow rate in the pipe is too high. On the contrary, you can analyze whether such a small flow rate for a pipe of this caliber is worth measuring? The results of this judgment give us preliminary ideas on whether to focus on processing small flows or focusing on processing large flows. If the analysis results indicate that there is no objection for a given flow range, a gas turbine flowmeter equal to or smaller than the pipe size is usually selected. This ensures that small traffic can operate normally. When the flow rate slightly exceeds the upper limit, the surface can still operate normally, but the resistance loss is greater. Generally speaking, situations that exceed the external measurement range are relatively rare in industrial sites. The situation of too small traffic is very common.

1. Accuracy level: Generally speaking, the main reason for choosing a high-pressure gas turbine flowmeter is its high accuracy. However, the higher the accuracy of the flow meter, 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 instruments. For occasions where the conveying volume is not large, a medium precision level 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 flowmeter has a certain measurement range. The caliber of the flowmeter The choice is also determined by the flow range. The principle of selecting the flow range is: the small flow rate during use shall not be lower than the small flow rate that the meter allows to measure, and the large flow rate during use shall not be higher than the large flow rate that the meter allows to measure. For intermittent working situations where the actual running time of the instrument does not exceed 8 hours per day, choose 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 running time of the instrument does not exceed 8 hours per day, choose the actual When using, 1.4 times the maximum flow rate is used as the upper limit of the flow range. The lower flow limit of the instrument is 0.8 times the actual small flow rate.

3. Density of gas: For gas turbine flow meters, the main influence of fluid physical properties is gas density. It has a greater impact on the instrument coefficient, mainly in low flow areas. 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 greatly save energy, reduce transportation costs, and improve utilization.

5. Structural type:

(1) The internal structure should beUse 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 flow meter 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 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. Since there are many types and specifications of turbine flowmeters, especially the quality of products from different manufacturers, you should try your best to collect relevant technical standards and other information about the manufacturers and products when selecting, and make a decision after repeated investigations and comparisons.