Line leak detector

A dispensing system, comprising:

• a tank for holding a liquid;
• a dispensing unit for dispensing the liquid;
• a fluid conduit line providing fluid communication between the tank and the dispensing unit;
• a one-way valve disposed in the fluid conduit line, the portion of the fluid conduit line between the valve and the dispensing unit defining a liquid volume;
• and
• a leak detector in communication with the fluid conduit line and adapted to detect volumetric changes in the liquid volume, the leak detector comprising:
• a housing defining an interior bore therein;
• a piston disposed in the interior bore and movable along the interior bore, the interior bore and piston defining an expansible chamber;
• a biasing member for biasing the piston against movement within the interior bore;
• a liquid passage extending from the liquid volume to the expansible chamber;
• and
• a magnetostrictive sensor including a magnetostrictive waveguide, a magnet operably connected to the piston for movement therewith and in operative relation to said magnetostrictive waveguide, and pulsing and detection devices for detecting a position of the magnet along the magnetostrictive waveguide.