Rf level measurement handbook

It has a long standing reputation as a proven technology in the most demanding level process environments. Choose RF Admittance for reliable, proven and trusted performance. Universal II Level System This level system provides advanced internal Admittance circuitry that enables the system to ignore significant process coating deposits on the level sensor.

Keep Reading. The RF signal results in a minute current flow through the dielectric process material in the tank from the probe to the vessel wall. When the level in the tank drops and the probe is exposed to the even less conductive vapors, the dielectric constant drops.

This causes a drop in the capacitance reading and a minute Figure Click on figure to enlarge. This change is detected by the level switch's internal circuitry and translated into a change in the relay state of the level switch.

In the case of continuous level detectors vertical probes , the output is not a relay state, but a scaled analog signal. Both of these values are fixed. Therefore, when the probe is no longer surrounded by vapors K 1 , but by the process material K 2 , the resulting capacitance change is directly related to the difference in dielectric constant between the two media: The sensitivity of a capacitance sensor is expressed in pico-farads pF.

The capacitance unit is the farad, defined as the potential created when a one-volt battery connected to a capacitor causes the storage of one coulomb of electric energy. A pico-farad is one trillionth of that, and the sensitivity of an accurate capacitance detector is 0. This is the minimum detectable change in capacitance resulting from a change in dielectric constant K 2 -K 1. Table 7 gives the K 2 values of a variety of process materials. As the dielectric constant of the process material gets close to that of air K 2 for plastic pellets, for example, is 1.

The ClearLine is an in-line fluid detector point switch designed for empty pipe detection. The Dumpstar is a point level control for oil and water interface designed to reduce product loss with water dump. The Multipoint II level switch product offers three control points located anywhere along a single vertically inserted level sensing element.

One control point can be set up for differential measurement for pump control. This product is best suited to sump level control and batch processing. Drexelbrook 3A probes are level sensors with the unique requirements of the food industry and optimized for hygienic applications requiring CIP and SIP cleaning operations.

Gapless designs, FDA certified materials and fittings, allow trouble free long-term use. The Drexelbrook Plugged Chute Detector is designed to measure the presence of material in bulk solids chutes.

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