Low-cost high-performance annular metallic seal for high pressures and large diameters

1. An annular metal static seal, comprising:

a first annular bearing plate and a second annular bearing plate facing each other, the first annular bearing plate having a first uniform thickness and the second annular bearing plate having a second uniform thickness, wherein the first uniform thickness and the second uniform thickness are the same, the seal being characterized in that it further includes an annular central portion perpendicularly connecting together said first and second annular bearing plates and secured in sealed manner to each of them via a respective annular weld, the assembly thus presenting a section in the shape of the letter H on its side.

2. An annular metal static seal according to claim 1 , characterized in that each of said first and second annular bearing plates is of undulating shape.

3. An annular metal static seal according to claim 2 , characterized in that said undulating shape comprises a recess between two bulges, at least one of which is for pressing against a facing surface where sealing is to be provided.

4. An annular metal static seal according to claim 1 , characterized in that said annular central portion presents a U-shaped section that is widely open in a radially outward direction.

5. An annular metal static seal according to claim 4 , characterized in that each of said first and second annular bearing plates includes an undulating shape, and said undulating shape comprises a recess between two bulges, said annular welds are made continuously over 360°, preferably without filler material, between inside surfaces of the first and second annular bearing plates on respective inside flanks of said recesses and an inside surface of said annular central portion substantially at positions close to its ends.

6. An annular metal static seal according to claim 5 , characterized in that said inside flanks of said recesses of said first and second annular bearing plates and said ends of said annular central portion have slopes that are substantially identical.

7. A method of fabricating an annular metal static seal according to claim 1 , characterized in that it comprises the following steps:

making the annular central portion by forming a first metal sheet of predetermined thickness and welding its ends together so as to make a closed ring;

making each of the first and second annular bearing plates by stamping a second metal sheet of predetermined thickness; and

continuously welding said first and second annular bearing plates over 360° to said annular central portion.

8. A method according to claim 7 , characterized in that each of said first and second annular bearing plates includes an undulating shape, and said undulating shape comprises a recess between two bulges, and said step of continuously welding over 360° is performed without adding filler material between inside surfaces of the first and second annular bearing plates on inside flanks of said recesses and an inside surface of said annular central portion at positions close to its ends.

9. A method according to claim 7 , characterized in that said first and second metal sheets are of different thicknesses.

10. A mechanical system including an annular metal static seal according to claim 1 .

11. An annular metal static seal, comprising:

a first annular bearing plate having an inner surface and an outer surface, and a second annular bearing plate having an inner surface and an outer surface, wherein the inner surfaces of the first and second annular bearing plates face each other, the seal being characterized in that it further includes an annular central portion perpendicularly connecting together said first and second annular bearing plates and secured in sealed manner to each of them via a respective annular weld, the assembly thus presenting a section in the shape of the letter H on its side, wherein the inner surface and the outer surface of said first and second annular bearing plates each have an undulating shape.

12. The annular metal static seal according to claim 11 , wherein the first annular bearing plate has a first uniform thickness and the second annular bearing plate has a second uniform thickness, wherein the first uniform thickness and the second uniform thickness are the same.