Advantages Of Vortex Flow Meter for Steam Application

From all the types of flow meters, a few are suitable for steam application and they are as it follows: turbine flow meters (shunt or bypass types both), pilot tubes, variable area flow meters and spring loaded variable area flow meters, orifice plate flow meters, direct in-line variable area (DIVA) flow meter and last but not least vortex shedding flow meters. Since each of these are optimal steam flow meters, and of course all of them have both advantages and limitations, to chose the perfect one you must match it to the applications. I thought going over each of them to get a basic picture would be a great approach.

The advantages of turbine flow meters are has an accuracy of ±0.5%, they are relatively low cost and a turndown of 10:1 is achievable, while the disadvantage are wet steam damages the turbine wheel and this can affect the accuracy, and even steam pressure variations, flow oscillations can affect the accuracy, the fluid must be very clean, it is viscosity sensitive, and low flow rates can be lost.

The advantages of pilot tubes consist of its price, it is very inexpensive, simple types can be used on various pipes (referring to the diameter of these pipes) and it has a little resistance to flow. The disadvantages consists of the turndowns being limited to approx. 4:1, if the steam is wet the bottom hole are as good as blocked, the placement inside the pipe work is critical and it is too sensitive to changes in turbulence.

The advantages of variable area flow meters can be the linear output, it is very simple and the pressure drop is minimal while the turndown is approx, 10:1, and the disadvantage are the limit in pressure and temperature due to transparent taper tubes, these tubes have to be mounted vertically and the accuracy is only moderate. Now the spring loaded variable flow meter can count as advantage its turndowns (25:1), an accuracy of ±2%, low cost, and as disadvantage it has a limited size and the wet steam damages it in the long run.

Orifice plate flow meters are one of the basic choice it is simple, low cost, gives a good accuracy and it doesn’t need calibrations or recalibrations. But for this you have a limited turndown (4:1), can block a system since it can buckle, it can erode easily due to wet, dirty steam.

The Diva flow meter possess a turndown ratio of up to 50:1, it costs energy as raw material and can easily identify areas for energy savings

The Vortex Shedding flow meter presents little resistance to flow, has no moving parts, but has a shortcoming against vibrations which can cause errors in accuracy, and won’t be working without long, clean lengths of pipework.