Direct mounting reverse buckling disc

In combination, an inlet pipe flange and an outlet pipe flange and a safety pressure relief device mounted directly between said flanges:

• a. said inlet and outlet flanges respectively having radially projecting opposed, flat annular clamping faces, said inlet and outlet flanges each having a bore extending through said flange to said clamping face,
• b. said relief device comprising a rupture disc arrangement having a flange portion extending therefrom, said rupture disc arrangement being of the reverse buckling type having a bulged central portion with a convex side,
• c. a first centering ring comprising a tubular wall portion and a flange portion, and puncturing means mounted at least partially within said first centering ring tubular wall portion, said bulged central portion being directed away from said puncturing means,
• d. said first centering ring tubular wall portion being telescopically received into said outlet bore,
• e. means cooperating between said first centering ring flange portion and disc arrangement flange portion whereby said last named flange portions are radially coaxially retained with respect to each other in absence of said pipe flanges,
• f. a second centering ring comprising a tubular wall portion surrounding said bulged central portion and a flange portion, said second centering ring tubular wall portion forming a mouth and being telescopically received into said inlet bore, means cooperating between said second centering ring flange portion and disc flange portion whereby said last named flange portions are radially coaxially retained with respect to each other in absence of said pipe flanges, and
• g. means clamping said first and second centering ring flange portions and rupture disc flange portion in sandwiched arrangement between said pipe flanges.