Patent ID: 8464752

Claim:
A blowout preventer for sealing a well, the blowout preventer comprising: a body having first and second chambers, the first chamber extending substantially perpendicular to and intersecting the second chamber; a ram block selectively moveable from within the first chamber to the second chamber to define a seal in the second chamber; a connecting rod connected to the ram block and configured to extend along the first chamber; a piston connected to the connecting rod and configured to move along and within the first chamber and move the ram block in and out of the second chamber; a bonnet configured to receive the piston, the bonnet being detachably attached to the body; an indicator device having at least a portion disposed outside the bonnet when the ram block is in the first chamber and in the second chamber, and configured to indicate where the ram block is within the body; and a third magnet are disposed at an end of the piston opposite the first magnet and along an axis of the first chamber, with the second magnet between the first and third magnets, so that when the piston moves within the bonnet, the first magnet and third magnet move the second magnet to indicate a position of the ram.