Liquid filling control method for multiple tanks

A method of automatically controlling the filling of a ship's fuel tanks with fuel from a supply source, the fuel tanks being equipped with overflow sensing means that detects an overflow condition indicative of the fuel tanks being filled to capacity, said method comprising the steps of:

• coupling a controllable valve to the supply source wherein the liquid dispensed therefrom must pass through said controllable valve when the plurality of tanks are being filled;
• providing an increment that said controllable valve can be opened and closed when liquid is being dispensed therethrough;
• opening said controllable valve to an initial position, wherein said initial position defines a flow rate through said controllable valve that falls within a range of acceptable flow rates;
• dispensing the liquid from the supply source through said controllable valve in said initial position;
• monitoring, for an amount of time, each of (i) a flow rate of the liquid being dispensed, (ii) a level of the liquid in each of the plurality of tanks, and (iii) a state of the overflow sensing means, wherein (i) an average flow rate, (ii) an average level, and (iii) an average state, respectively, are defined for said amount of time;
• moving said controllable valve by said increment when said average flow rate is outside said range of acceptable flow rates, wherein said controllable valve is closed by an amount equal to said increment when said average flow rate is greater than said range, and wherein said controllable valve is opened by an amount equal to said increment when said average flow rate is less than said range;
• waiting a predetermined wait time following an occurrence of said step of moving, said predetermined wait time being equal to the sum of (i) a first time interval equal to the time needed for said controllable valve to move said increment, and (ii) a second time interval based on a plurality of factors to include the number of fuel tanks and location of said controllable valve relative to where said flow rate is being monitored;
• and
• initiating a finalize filling process when one of a number of events occurs, said number of events including (i) said average level being equal to a predetermined percentage of the capacity of the fuel tanks, and (ii) said average state indicating said overflow condition, said finalize filling process fully closing said controllable valve in accordance with a series of discrete movements of said controllable valve carried out over a specified time period;
• and
• repeating said steps of monitoring, moving and waiting until one of said number of events occurs.