1. Field of the Invention
This invention relates in general to closing devices for pressure vessels and in particular to a closure head for a coke drum.
2. Description of the Prior Art
In a coke manufacturing process, high temperature petroleum products are placed inside a large pressure vessel. The pressure vessel may be as much as 80 feet high, with a nozzle or discharge opening on its bottom. A head, which is a large, flat plate up to six or seven feet in diameter, secures across the opening of the nozzle. The plate bolts to a flange on the pressure vessel by a large number of bolts.
Subsequently, the high temperature petroleum products will be quenched and cooled with water, forming coke. After cooling, the head is removed and a chute positioned below the nozzle. High pressure water jets will be used to break up the coke, which flows out the opening of the nozzle.
The process of removing and reinstalling the head is time consuming and messy. A carriage moves under the head to engage the lower side and provide support during the removal and installation process. Workers must physically unscrew all of the bolts, which can number 60 or so. There have been various proposals in the past to improve head closures, however generally these proposals are complex.