Patent ID: 7491320

Claim:
An apparatus for estimating blockage within a liquid strainer used in a marine vessel comprising: a sensor for measuring a rate of liquid flow through a liquid strainer on a marine vessel; a sensor for measuring an operational speed of a device on a marine vessel that utilizes the strained liquid; a central processing unit configured to: receive at least one measurement from the liquid flow rate sensor; receive at least one measurement of operational speed from the operational speed sensor; and compare a relationship of the measured liquid flow rate and measured device speed to a predetermined reference relationship of liquid flow rate and device speed at an equivalent device speed to determine a degree of blockage in the liquid strainer and further comprising a removable magnet/paddlewheel assembly within the liquid flow sensor and a valve adjacent to the liquid flow sensor, wherein the magnet/paddlewheel assembly is not removable when a handle on the valve is oriented in a valve open position.