Pipe coupling gasket assembly

1. A conduit coupling assembly configured to clamp to a fluid conduit oriented about a longitudinal axis comprising:

an arcuate clamp ring having a first longitudinal edge and a second longitudinal edge;

a spanner configured to extend across a longitudinal ring gap between said first longitudinal edge and said second longitudinal edge of said clamp ring;

said spanner having a spanner arc length transverse to said longitudinal axis from a first longitudinal edge to a second longitudinal edge;

a connecting assembly configured to tighten said spanner and said clamp ring to said fluid conduit from a non-actuated position to a tightened position;

an arcuate gasket configured to be positioned between said clamp ring and said spanner on an outer side of said gasket and said fluid conduit on an inner side of said gasket;

said gasket comprising a spanner recess in said outer side of said gasket;

said spanner recess having a recess arc length transverse to said longitudinal axis from a first longitudinal edge to a second longitudinal edge; and

said spanner recess configured to receive at least a portion of said spanner such that said first longitudinal edge of said spanner and said first longitudinal edge of said recess are opposed to each other and said second longitudinal edge of said spanner and said second longitudinal edge of said recess are opposed to each other.

2. The conduit coupling assembly set forth in claim 1 , wherein said gasket comprises an outer cylindrical arc surface and said spanner recess comprises a radial recess in said outer cylindrical arc surface of said gasket configured to receive at least a portion of said spanner.

3. The conduit coupling assembly set forth in claim 2 , wherein:

said radial recess of said spanner recess has a radial depth;

said spanner comprises a cylindrical arc portion having a radial thickness; and

said radial recess and said cylindrical arc portion have a radial depth to radial thickness ratio of between about 0.5 and about 0.9.

4. The conduit coupling assembly set forth in claim 2 , wherein:

said radial recess of said spanner recess has an axial width;

said spanner comprises a cylindrical arc portion having an axial length; and

said radial recess and said cylindrical arc portion have an axial width to axial length ratio of between about 1.01 and about 1.5.

5. The conduit coupling assembly set forth in claim 1 , wherein said gasket comprises an outer end wall and said spanner recess comprises an axial recess in said outer end wall of said gasket configured to receive at least a portion of said spanner.

6. The conduit coupling assembly set forth in claim 5 , wherein:

said axial recess of said spanner recess has an axial depth;

said spanner comprises an annular arc portion having an axial thickness; and

said axial recess and said annular arc portion have an axial depth to axial thickness ratio of between about 0.9 and about 1.1.

7. The conduit coupling assembly set forth in claim 6 , wherein:

said axial recess of said spanner recess has a radial width;

said spanner comprises an annular arc portion having a radial length; and

said axial recess and said annular arc portion have a radial width to radial length ratio of between about 1.01 and about 1.5.

8. The conduit coupling assembly set forth in claim 1 , wherein

said spanner recess and said spanner have a recess arc length to spanner arc length ratio of between about 1.01 and about 1.5.

9. The conduit coupling assembly set forth in claim 1 , wherein said gasket comprises an outer gasket layer and a separate inner gasket layer and said inner and outer gasket layers configured to be selectively engaged with each other.