Patent ID: 7229233
Filing Date: 2007-06-12
Classification: G01M,Y10T

Abstract:
1. An underground storage system comprising: an underground storage tank; a double walled riser sump having a vertical wall terminating in a top, the vertical wall including an inner wall and a spaced apart outer wall, the outer wall and the inner wall defining an annular space; and a monitoring liquid reservoir containing a liquid and being in fluid communication with the annular via a liquid supply tube and a liquid vent tube; wherein the monitoring liquid reservoir is a separate container from the vertical wall of the riser sump; wherein the vertical wall is formed from a riser and a collar, the collar being attached to the underground storage tank and the riser being attached to the collar, the riser being formed from an inner riser wall and an outer riser wall that together define a riser annular space, the collar being formed from an inner collar wall and an outer collar wall that together define a collar annular space, the riser annular space and the collar annular space being in fluid communication with each other; and wherein the reservoir is positioned near the top of said vertical wall, whereby the reservoir is accessible from a space adjacent said top, and wherein the reservoir includes two holes, the first of said holes being a vent hole for communicating ambient air to the reservoir and the second of said holes providing for the insertion of sensing means into the reservoir.