This flow meter type is popular in industries such as: food and beverage, pharmaceuticals, wastewater management and water treatment, pulp and paper, power, HVAC, and mining. Within these industries and others, they are often used to measure the flow of dirty and highly hazardous or corrosive fluids. They are so useful for these types of applications because, since they do not actually come in contact with the fluids, the flow meter sensor heads are not at risk for damage like corrosion.
Instead of reading flow from inside the pipe, they read flow from the outside of the pipe, the surface to which they are clamped. There, the flow meter sensor(s) collect flow data by sending and receiving ultrasonic pulses. They send their collected data to a connected readout for interpretation. Typically, this readout device is digital, but it can also use analog outputs, relay outputs, binary + RTD inputs, or a combination of all of them.
Most often, these highly useful flow meters come in single and dual-sensor models. Single sensor meters work using piezoelectric transmit and receive crystals that are planted in just one sensor body. Customers clamp these onto a single point on the pipe surface and connect the sensor to the pipe using a coupling compound. Dual-sensor meters are built with the transmit crystal in one sensor body and the receive crystal in the other.
The main drawback of clamp-on flow meters is the fact that they do not work well with pipes that are lined, particularly linings of copper, concrete, plastic or fiberglass. This is because the lining interferes with transmit and receive signals, making the flow meter readings inaccurate.
Nevertheless, the unique, non-invasive nature of clamp-on flow meters presents a variety of benefits. First, the monitored flow remains undisturbed and without pressure drops. This allows for undistorted, more accurate readings. In addition, during installation, it is not necessary to break open your pipe system in order to insert the flow meter. Rather, you can easily install and uninstall the meter by clamping on to your pipe. This not only saves you time and money, but also makes it less likely that your system will leak or become contaminated. Also, because your meter will not be exposed to fluids, it will last longer. This is cost-effective both in the short and the long run; if you like, when you’re done with one application, you can remove your meter from the pipe and use it on another.