Patent ID: 7241137

Claim:
A flame arrestor for a flowing explosive gas, having a disk structure with a front face and a back face, the disk structure comprising: structure forming multiple concentric rings of first gas passages, about a longitudinal axis in a flow direction, extending from the front face to the back face, said first gas passages each having a cross-sectional area, normal to the flow direction, larger than a given value; and structure forming at least one ring of second gas passages, said ring being substantially concentric with said multiple concentric rings of first gas passages, said second gas passages extending in the flow direction and each having a cross-sectional area, normal to the flow direction, less than the given value, wherein said multiple concentric rings of first gas passages and said at least one ring of second gas passages are arranged in an alternating pattern, such that said at least one ring of said second gas passages surrounds at least one ring of said first gas passages.