The ultrasonic flowmeter provides numerous advantages over other types of flow measuring meters. The main advantage provided is ultrasonic measurements are non-invasive. The flow of fluid is measured by clamping a set of transducers on a pipe. Because in most cases the transducers are placed on the outside, they do not come in contact with the fluid.
Ultrasonic flowmeters are the equipment of choice whenever the contact with the measured fluid isn’t possible. Ultrasonic measurements are made by attaching two transducers onto the outside of a pipe. This installation method is perfect for all situations in which neither cutting the pipes nor the shutting down of the process is impossible. These externally applied flowmeters don’t suffer any mechanical wear and tear. They don’t cause the pressure to drop.
This method has no need to shut down the machine or cut a pipe during installation. Bidirectional measurements can be done with clamp-on flowmeters.
These sensors can be mounted either on the exterior or inside the pipes. In most situations, the exterior installation works very well. However, in case of uneven wall thickness or corrosion problems, the transducers have to be inserted through the pipe, in order to be able to work properly. Advanced technologies of digital signal processing have made it possible to attach digital coding to the beamed sound waves. This is a good method to eliminate lots of problems such as noise and density variations. Flowmeters that use the transit time method can be used only in conditions of clean fluids, with barely any gas bubbles or suspended solids. Besides, the fluid has to be inside a full and closed pipes system.
These ultrasonic flowmeters are used on closed full pipes and the transducer may be mounted either on the outside of the pipe or inserted (hot tapped) into the pipe.