RF Admittance Level Switch

Cape-11 RF Admittance Level Switch is a level measurement instrument mainly designed for powdery coal ashes, solid granules and adhesive materials. It possesses merits and benefits of other similar products in the market. Besides, Jiwei has developed innovative techniques and manufactured technologies to make Cape-11 more competitive and has higher reliability as well as stronger flexibility.

In Cape-11 RF Admittance Level Switch series products, a probe is designed to detect the change of capacitance and impedance between probe and vessel wall to fulfill material level measurement and control. In its electronic unit, reactance between measurement electrode and the wall of an empty vessel constitute a balanced bridge circuit which outputs a stable oscillation signal. As medium level rises, measured medium covers measurement electrode, reactance between electrode and the wall of vessel changes. It causes imbalance of bridge circuit and stops the oscillation as a result. A post-circuit is designed to detect the change of output signal from bridge circuit and generate an alarm signal. In addition, oscillation signal at radio frequency is not only applied to the measurement electrode but also applied to a shield pole through a 1: 1 voltage-follower, so measurement electrode and shield pole have the same electric potential, phase, and frequency, but these two electrodes are insulated from each other. Even if there is medium buildup on probe, because there is no electric potential difference between measurement electrode and shield pole, and the reactance change on shield pole has no effect on the detection of post-circuit. Therefore, only reactance change on measurement electrode induced by the filled medium between measurement electrode and the wall of vessel will be detected by post-circuit. It eliminates the effect of medium buildup on level measurement.

Cape-11 RF Admittance Level Switch series include 4 models (Standard, Guard, Rope and Ultra-high Temperature):

Cape-11A Standard: Suitable for level measurement of dust and coal ash etc., flexible and easy for installation and maintenance.

Cape-11P Guard: A stainless steel protective sleeve assembled on standard Cape-11 to enhance impact resistance of instrument for heavy materials.

Cape-11R Rope: Suitable for large silos or bunkers, install vertically to effectively avoid material impact from side.