Double-walled contained shear valve, particularly for fueling environments

A shear valve for use with a fuel dispenser, comprising:

• a housing having an axial length extending between a first end and second end thereof, said housing defining a shear groove on the outside circumference of the housing, said housing being initially unbroken at said shear groove but breakable at said shear groove in response to a shearing force;
• the housing containing an orifice therein forming a fuel flow path;
• a main valve coupled to the housing that is adapted to close the fuel flow path to prevent flow of fuel, wherein the main valve is adapted to close off an upstream fuel flow path in response to a shear, and wherein the housing contains a main valve seat along the orifice engaged by the main valve when closed;
• a flexible leak skirt fixed to an exterior of the housing at a first location upstream of said shear groove and a second location downstream of said shear groove and comprising an elastomer material, said leak skirt surrounding the unbroken shear groove but not surrounding a remainder of said housing along said axial length thereof further upstream and downstream of said first and second locations to provide a leak containment chamber to contain fuel leaking through the shear groove in the event of a leak that subsequently occurs at the shear groove due to break at said shear groove;
• and
• a secondary poppet valve and secondary poppet valve seat in the housing, said secondary poppet valve adapted to close off a downstream fuel flow path from the housing fuel flow path in response to a shear.

A shear valve that carries fuel from a branch or main fuel piping to fuel dispenser piping, comprising:

• a housing defining a shear groove on the outside circumference of the housing, said housing being initially unbroken at said shear groove but breakable at said shear groove in response to a shearing force;
• the housing containing an orifice therein forming a fuel flow path;
• a main poppet valve coupled to the housing that is adapted to close the fuel flow path to prevent flow of fuel;
• a flexible leak skirt coupled to an exterior of the housing, said leak skirt surrounding the unbroken shear groove to provide a leak containment chamber to contain fuel leaking through the shear groove in the event of a leak that subsequently occurs due to a break at said shear groove;
• and
• wherein said housing defines a containment housing and an inner housing coupled to the containment housing, and partially or fully surrounded by the containment housing, such that an interstitial space is formed separate from the fuel flow path between the containment housing and the inner housing.

A shear valve for use with a fuel dispenser, comprising:

• a housing defining a shear groove on the outside circumference of the housing, said housing being initially unbroken at said shear groove but breakable at said shear groove in response to a shearing force;
• the housing containing an orifice therein forming a fuel flow path;
• a main valve coupled to the housing that is adapted to close the fuel flow path to prevent flow of fuel, wherein the main valve is adapted to close off an upstream fuel flow path in response to a shear, and wherein the housing contains a main valve seat along the orifice engaged by the main valve when closed;
• a flexible leak skirt coupled to an exterior of the housing comprising an elastomer material, said leak skirt surrounding the unbroken shear groove to provide a leak containment chamber to contain fuel leaking through the shear groove in the event of a leak that subsequently occurs at the shear groove due to break at said shear groove;
• a secondary poppet valve and secondary poppet valve seat in the housing, said secondary poppet valve adapted to close off a downstream fuel flow path from the housing fuel flow path in response to a shear;
• and
• wherein said housing defines a containment housing and an inner housing coupled to the containment housing, and partially or fully surrounded by the containment housing, such that an interstitial space is formed separate from the fuel flow path between the containment housing and the inner housing.