Safety clamping system for pressure vessel closures and the like

Clamping apparatus for a chamber member having an aperture surrounded by a seat that is engageable by a closure member to seal the aperture, with a plurality of clamping devices for the closure member;

• at least one of said clamping devices comprising
• a hub member including a cylindrical hub having a through bore on a pivot axis parallel to the axis of the hub and eccentrically offset therefrom,
• means on one of said chamber and closure members for pivotally supporting the hub member on said pivot axis for controllable rotation between a closure clamping position and a closure relieving position,
• a clamp arm journaled adjacent one end on said cylindrical hub and swingable about the hub axis between an idle position and a working position,
• said clamp arm carrying at its other end rigidly mounted hook structure in position to be free of the other of said chamber and closure members in idle angular position of the clamp arm, and to be engageable with said other member in working angular position of the clamp arm,
• said eccentric offset being such that, in working position of the clamp arm, the hook structure clamps the closure member to the seat in clamping position of the hub, and permits positively limited closure movement away from the seat in relieving position of the hub.

Clamp structure adapted for mounting between fixedly supported spaced parallel mounting plates and comprising

• handle arm means having adjacent one end two oppositely facing parallel surfaces with mutually aligned cylindrical bosses projecting from the respective surfaces, with a through bore parallel to the common axis of the bosses and eccentrically offset from that axis by a distance such that the bore is within, or internally tangent to, the cylindrical boss surfaces,
• clamp arm means journaled adjacent one end on said bosses and carrying at the other end rigidly mounted hook means,
• one of said arm means comprising two portions which are approximate mirror images of each other with the other arm means rotatably received between them, the resulting assembly having an axial dimension adjacent said bore to fit between said mounting plates,
• and a pivot pin insertable through said bore and through aligned holes in the mounting plates.

In combination with a chamber having an aperture surrounded by a seat, a closure member mounted by hinge means at one side of the aperture, and clamping means for releasably securing the closure member in sealing relation to the seat;

• improved handle means for swinging the closure member from the seat after release of the clamping means, comprising
• bracket means extending generally radially from the closure member opposite the hinge means and carrying a hand hold,
• a recess in the bracket means having a flaring mouth facing toward the chamber,
• and a fixture rigidly mounted on the chamber in position to be received in the recess as the closure member approaches the seat, and thereby to center the closure member with respect to the seat.

Method of insuring safe release of residual pressure from a pressure vessel before opening a manway that is normally sealed by a cover clamped to a peripheral seat by a plurality of angularly spaced clamping devices;

• said method comprising
• hinging the cover to the vessel at one side by hinge means which permit limited translational cover movement away from the seat,
• providing means associated with at least one clamping device approximately opposite the hinge means for blocking release of that clamping device until all other clamping devices are released,
• releasing first said other clamping devices, to cause any residual pressure to lift said one side of the cover the limited distance permitted by the hinge means and thereby to equalize pressure in the vessel.
• then releasing said at least one clamping device and swinging the cover open about the hinge means.