Blowoutpreventer stacks and method of tensioning stack tie rods

摘要

An improved blowout preventer stack including a plurality of ram type blowout preventers, an annular blowout preventer, a plurality of tie rods connecting said blowout preventers into a stack, the upper ends of the rods being secured to the side of the upper member of the stack and the lower end of the rods being secured to the lower end of the stack with securing means to maintain the preset tension in the tie rods. An improved test stump is provided to support the stack and connect to and exert tension on the tie rods responsive to pressure supplied to the test stump to preset the tension therein. The improved method of the present invention includes the step of assembling the components into a stack supported on the test stump, securing the tie rods to the upper member of the stack, connecting the pressure responsive means of the test stump to the lower end of the tie rods, supplying pressure to the pressure responsive means of the test stump to pretension the tie rods and tightening the securing means on the end of the tie rods to maintain the preset tension in the tie rods.