In many industrial applications requiring flow measurement for gas and liquid passing through a process pipeline, a variable area flow meter determines the flow rate in volume units. Variable area flow meters are also known as rotameters. The measurement mechanism consists of a freely moving float inside a tapered tube. This freely moving float finds the equilibrium. The device includes a scale attached either outside or inside the tube used in reading the flow rate. Regarding popularity, rotameters are the most commonly used type of variable area flow meter.
Advantages of using a rotameter
There are several benefits to using a rotameter in measuring fluid and gas flow. Below are some of the characteristics of a rotameter which makes it the preferred measurement device for fluid and gas flow rate in many industrial applications.
- No need for external power. Unlike other kinds of flow meters, a rotameter operates mechanically. There is no need for a power input for the device to work. Since no power supply is required, rotameters are suitable for applications in hazardous conditions where the power supply is limited or considered a source of danger itself.
- The process is visible. Variable area flowmeters allow a clear view of the process involved. Engineers or technicians can check if the fluid is cloudy and needs filter replacement. In addition to this, it is easier to check if there are underlying concerns such as unusual fluid colour or bubbles.
- Cheaper option. One of the most significant benefits of rotameters is cost-effectiveness. The price and function of the device contribute to additional savings. The device is also compatible when combined with other technologies used in flow measurement.
- Easy maintenance and installation. Installing a rotameter requires the pipeline into the outlet and inlet of the device. There are no complicated installation procedures. As long as the meter sits vertically, flow measurement can commence.
- Low-pressure drop. Pressure drop determines the size of the pumps. Since rotameters have a low-pressure drop, you can install these devices in several areas of the process.
- Measurement repeatability. Rotameters are reliable in repeated measurement accuracy as long as the same process conditions exist.
Type of material used
Variable area flow meters use different kinds of material in their fabrication. Here is a comparison of varying area flow meters according to the kind of material used:
- Plastic flow meters are the cheapest solution if you are looking for non-corrosive properties and suitability to low-pressure conditions. Plastic flow meters are compatible with both gas and liquids.
- Glass flow meters have better accuracy than plastic flow meters. These are most suitable for gasses and have a more extensive flow range.
- Metal flow meters are best for measuring the flow rate of fluids in hazardous conditions. Metal flow meters are also ideal for extremely high and low-temperature applications. This type of flow meter has a simple design that is easy to install, maintain, and operate.
Variable area flow meters will continue to be one of the most popular types of flow meters used for a variety of applications in industrial and commercial settings because of their versatility and simplicity.