Nuclear low pressure packing casing for rotary machine and casing fabrication method

摘要

A nuclear low pressure packing casing having reduced horizontal joint leakage. This is accomplished by providing packing ring carriers that are separately formed from the casing so that thermal distortion loads will not be transmitted to the horizontal joints. In an embodiment of the invention, the packing ring carriers are fit in place in pre-machine grooves in the casing rather than being welded directly to the casing. According to further, optional feature of the invention, the vent or seal steam enters or exits at only one of the bottom quadrants rather than the entire bottom half so that the packing case design can be simplified to reduce fabrication and material costs.