Abstract: In one aspect of the present invention, a sensor detects particles within a fluid. The sensor includes a housing that defines a cavity. A magnet is disposed adjacent the cavity bottom to attract particles into the cavity. A first coil is wound about the outer surface of the cavity. The induction of the first coil is responsive to the particle accumulation within the cavity. A second coil is wound about the magnet. The induction of the second coil is responsive to the temperature of the fluid and independent to the particle accumulation within the cavity.

Abstract: An apparatus is used for sensing liquid level in a vessel at multiple levels and with variable resolution using optical properties. Known electrical optical sensing devices are not adequate for applications where multiple level, fine or variable resolution sensing are desired. The subject liquid level sensor includes a mounting apparatus adapted for insertion into the vessel, for containing the electric circuit, and for filtering the liquid entering the sensor. In addition, the sensor includes an array of sensing elements electrically connected in parallel and attached along the mounting apparatus spaced from one another at preselected locations. The sensing elements are adapted to deliver a plurality of electric signals in response to the absence of liquid at the level of the respective sensing element. The electric signals are then summed by an amplifier, which then delivers a resultant liquid level signal.