Vortex flow meter gas is mainly used for industrial pipeline gas, liquid, steam and other media measurement, which is characterized by small pressure loss, large range, high accuracy, in the measurement of the working condition of the volume flow is almost independent of the fluid density, pressure, temperature, viscosity and other parameters. No moving mechanical parts, so high reliability, low maintenance, instrument parameters can be stable for a long time. Use steam flow meter vortex type is mainly used for steam, water, nitrogen, and raw materials flow measurement.
Scope of application of Vortex flow meter gas
Vortex flow meter gas is suitable for measuring the volume flow of liquids, gases, steam and other fluids which are single-phase, clean without pulsation and vibration, with the Reynolds number of 2 × 10^4 ～ 7 × 10⁶, the viscosity ＜20 mPa-s, and the volume flow rate of liquid, gas, steam and other fluids which are 10∶1 ～ 25∶1. When measuring the volume flow rate of natural gas, gas and other fluids, should be used to rotate into the vortex flow meter. steam flow meter vortex type has a small pressure loss, simple and solid structure, no moving parts and easy to install and maintain, etc., and at the same time has a variety of diagnostic functions.
steam flow meter vortex type is not suitable for measuring low static pressure, dirty media flow; not suitable for measuring low Reynolds number ( Re ≤ 2 × 10 ^ 4 ), high viscosity, pulsating flow, low velocity fluid flow.
Steam Flow Meter Selection and Design
Steam is divided into superheated steam and saturated steam. For superheated steam flow measurement requires temperature and pressure compensation; saturated steam requires only temperature or pressure compensation. In the two compensation methods, the priority choice of pressure compensation, design selection method and gas selection is basically the same. The most commonly used orifice plate flowmeter in previous projects. Compared with the orifice plate flow meter, steam flow meter vortex type has the advantages of small pressure loss, do not need to lead the pressure pipe valve parts; do not need to accompany the heat pipe, thermal insulation box; installation is simple, low installation and operating costs and so on. It is widely used in petrochemical projects due to its high cost performance.
Scientific selection of Vortex flow meter gas
Vortex flow meter gas can be divided into 3 types according to the sensors, i.e. flange type, clamping type and insertion type. Priority should be given to the flange type, which is more widely used, and then the clamping type should be considered. Clamping type flow meter, insertion type flow meter in the installation is very easy to affect the accuracy, and once the installation is not scientific and standardized, will cause the measurement is not accurate, error phenomenon. Insertion type steam flow meter vortex type is mainly used in occasions that do not require precise control and measurement.
Vortex flow meter gas is also divided into integral type and split type. If the meter is installed in high temperature or in high altitude or wells, the split meter is usually applied, the main purpose is to improve the working environment of the meter, and convenient maintenance of the meter. In the implementation of the integrated instrumentation process, you need to leave enough space around the installation point, the purpose is to facilitate the installation of wiring, as well as to make future maintenance work more convenient.
Vortex flow meter gas fault analysis and troubleshooting
Reasons for meter selection
(1) Due to improper selection of the meter diameter, so after installation and commissioning, the actual flow rate and the range of the meter is far from the main performance of the pipe diameter, small flow rate, low flow rate, the actual flow rate is at the lower limit of the meter or below the lower limit, the meter can not run normally, the measurement error is very large.
(2) Selection of the table, the working condition parameters to provide inaccurate, and the actual working conditions are very different, resulting in improper selection of the meter, the instrument is installed and put into operation, can not be normal operation, especially gas flow measurement of the selection of the table, the operation of the pressure deviation on the measurement of the impact of the measurement of the large is particularly obvious.
Installation of improper reasons
(1) Instrument upstream and downstream straight section length is not enough, the gasket protrudes into the pipe, the sudden contraction of the pipeline, the sudden expansion of the flow blocking parts of the flow field to produce serious perturbations and so on.
(2) the liquid measuring pipe containing trace gases or gas measuring pipe containing trace liquids of poor installation caused by heterogeneous fluids in the vortex flowmeter measuring pipe stagnation, the measurement of interference.
(3) Measurement of liquids when the vortex type flow meter installed in the top-down vertical flow or downward sloping flow of the pipeline, or vortex flow meter installed in the pipeline without back pressure at the exit of the object, resulting in the liquid is not full of pipe.
(4) vortex flow meter installation location from the power source (fan, or pump) is too close, there is no long enough upstream straight pipe section and effective vibration damping measures.
(5) Measurement of high-temperature media vortex type flow meter horizontal positive installation, the converter is located in the pipeline directly above the pipeline, pipe insulation measures are not in place, resulting in pipeline high temperature on the converter parts of the direct baking, resulting in damage to the electronic devices.
Reasons for the fluid
(1) The measured fluid is not a uniform single-phase fluid, it may be pulsating flow, or mixed-phase flow, resulting in unstable vortex separation and large fluctuations in the output signal.
(2) The fluid is mixed with lumpy solids, long fibers or bands. High-speed movement of lumpy solids impact on the generator and the detection element, serious damage to the generator and the detection element; long fibers and ribbons wrapped around the generator and the detection element, destroying the Karman vortex street stable separation, interference with the detection element stable work.
After a long period of work, the dirt in the fluid in the measuring tube wall and the detection element surface attachment, deposition, change the geometry of the measuring tube and the generator parameters, instrumentation, measurement error increases, reduces the sensitivity of the detection element, signal amplitude decreases, which in turn causes the detection element Failure of the detection element.
Environmental reasons
Corrosive gases in the environment, the long-term erosion of moisture will cause a decline in insulation resistance of the detection components, as well as some of the electronic components, terminals, grounding terminal corrosion, so that the contact resistance of the connector increases, the transmission signal is attenuated.
