Wet line fluid removal system with optical sensor

In a liquid cargo tank having a loading line communicating therewith, a system for the returning to said liquid cargo tank the residual liquid remaining in said loading line after loading or unloading of said cargo tank, said system comprising:

• a. a liquid return line extending between said loading line and said cargo tank;
• b. a pump positioned to move liquid from said loading line, through said liquid return line, and into said cargo tank;
• and
• c. a vapor line communicating between a vapor space in said cargo tank and said loading line, as liquid is moved from said loading line wherein as liquid is moved from said loading line vapor from said vapor space is transferred to said loading line at approximately ambient pressure.

An optical liquid level sensor comprising:

• a. a light tube having two substantially straight sections joined by a substantially continuous curvature bend, said bend having a rounded cross-section;
• b. an optical emitter positioned at an end of one of said straight sections of said tube, said emitter emitting light at a half angle of between approximately 30° and approximately 12°;
• c. an optical detector positioned at the other one of said straight sections of said tube;
• and
• d. control circuitry activating said optical emitter and monitoring said optical sensor.

A wireless overfill detection system comprising:

• a. an optical sensor positioned within a cargo tank to detect an overfill state;
• b. a wireless transmitter connected to said sensor and generating a signal to indicate when said sensor is in contact with fluid;
• and
• c. a control module for receiving signals from said wireless transmitter and for further generating signals to control the flow of fluid into said cargo tank.