Flödesprober

Flödesprober, or flow probes, are instruments for measuring the flow rate or velocity of a fluid in a pipe, duct, or open channel. They are used in process engineering, HVAC, laboratory research, and medical technology to monitor flow conditions and to control processes.

The common measurement principles include differential-pressure, thermal, ultrasonic, and mechanical methods. Differential-pressure probes insert a restriction such as an orifice, venturi, or flow nozzle and derive flow from the pressure drop using calibration. Thermal probes use a heated element; the rate at which heat is carried away by the fluid is proportional to its velocity. Ultrasonic probes determine flow by measuring the time it takes for an acoustic signal to traverse the flow in the direction of the flow and against it (transit-time) or by detecting Doppler-shifted reflections from particles. Mechanical probes use a turbine, paddle wheel, or other rotor whose rotational speed is proportional to flow. Some systems measure mass flow directly via Coriolis or other mass-flow methods, which are common in precise processes.

Installation and maintenance: Probes can be installed inline, inserting into a pipe, or clamped onto a pipe for non-invasive measurement. Proper straight-pipe sections and alignment improve accuracy; cleaning and avoidance of air bubbles or fouling are important. Calibration against known flow standards is often required.

Applications: Flödesprober are used to monitor and control liquids and gases in chemical, petrochemical, water treatment, HVAC and laboratory settings, as well as in some medical devices to monitor blood or respiratory gas flow.