Understanding Vortex Flow Meter Technologies
When the flow slows down or stops, the vortices slow down or stop. In the above examples, the whistling ceases and the flag quits waving when the wind dies down.
When flow hits an object, called a bluff body or shedder, the flow is separated and travels around the object before continuing downstream. On each side of the object vortex, swirls (vortices) occur that separate at the contact point of the object. The object causes vortex swirls on each side of the object. One side will have high-pressure swirls and the other side will have low-pressure swirls.
The swirls on each side of the object will be out of phase with the other by 180 degrees. Measuring the formation frequency of the vortices on either side of the object will determine the flow rate. Furthermore, the speed of the fluid is directly proportional to the width of the object and the frequency of the vortex.
Vortex flow meters work well for clean gases, steams and liquids that do not contain many solids. When dealing with low-density gases, greater attention is required as low-density gases generate weaker pulses, making the signals more difficult to detect. Low density gases are best measured with thermal dispersion type flow meters.
The most popular application for vortex meters is steam applications. Compared to other flow measurement devices, the vortex flow meter when used as a steam flow meter is cheaper, contains no moving parts, has a longer working lifetime than other flow measurement devices.
Vortex meters can measure each form of a fluid, including steam, liquid and gas. For industries needing a cost-effective, low maintenance, reliable method to measure flow, the vortex meter is best. Because it has no moving parts, the vortex meter does not require routine maintenance or cleaning.
In addition to measuring steam, the vortex flow meter can measure wet or dirty gases. The technology in a vortex flow meter measures the number of pulses created when an object is immersed in the stream of the flow. In a vortex flow meter, the object is machined into the meter. When the flow passes over the object, vortices are created on either side of the object, which allows the flow rate to be determined. This is done by calculating the number of vortices created inside the vortex flow meter by the steam.
SmartMeasurementTM ‘s ALVT family of vortex flow meters including wafer, flanged and insertion types will cover any vortex applications in the process industries. Moreover the ALVTmass produced by SmartMeasurementTM can take direct mass flow readings on steam or gas flow applications with built-in temperature and pressure sensors well as mass flow transmitter.