Clamp-on flow meters are a type of ultrasonic flow meter. They are also known as "non-intrusive" or "non-invasive" flow meters because they do not come in direct contact with the fluid flow they are measuring. Instead, they are attached, or clamped on, to the outside of the pipe.
Typically, clamp-on flow meters come in single and dual-sensor versions. To make the former, manufacturers plant piezoelectric transmit and receive crystals in the same sensor body. To connect the sensor to the pipe, manufacturers use a coupling compound. The latter version, on the other hand, features the transmit crystal in one sensor body, with the receive crystal in the other.
Once clamped on, the flow meter sensor(s) send and receive ultrasonic pulses. This information is collected and sent to a readout for interpretation. Usually, this is a digital readout, but it can also have relay outputs, analog outputs, binary + RTD inputs, or a combination therein.
Clamp-on flow meters are popular for use with very dirty fluid and highly corrosive liquids. This is because, since they do not actually touch the fluid, their sensor heads are not in danger of corrosion or other damage. They do not, however, work well with pipes that are lined, especially linings of concrete, fiberglass, plastic, or copper. This is because the lining interferes with transmit and receive signals, making the flow meter readings inaccurate.
Industries that make use of clamp-on flow meters include: wastewater management and water treatment, HVAC, power, mining, pulp and paper, food and beverage and pharmaceuticals.
Because they are not inserted into the flow, clamp-on flow meters offer the advantages of: undisturbed flow, undistorted readings and a lack of pressure drops; these benefits make them ultimately more reliable and more cost-effective than other flow meter types. In addition, you do not have to break open your piping system in order to install them. Not only does this save you time and money, but it also reduces the likelihood of leaks or flow contamination. Plus, you can easily remove them and use them on a different pipe when you're done.
Clamp-on flow meters are available in a wide range of pipe sizes, usually up to 10 meters or more, making them ideal for nearly any piping application. They are also available with different sensor materials, such as polyetherimide, stainless steel or aluminum, and different temperature tolerances. To learn more about your clamp-on flow meter options, reach out to an experienced flow meter manufacturer with your specifications.