Retractable packing ring lower half segment retaining key and method for retaining retractable packing ring lower half segment

A rotary machine comprising:

• a component rotatable about an axis;
• a stationary component including an annular groove about said axis, at least one axially directed locating flange about the axis and in part defining a slot opening into the annular groove, the stationary component being defined by upper and lower half housing parts secured to define a horizontal midline joint;
• a plurality of generally annular packing ring segments disposed about said axis, each segment having an arcuate seal face, at least one axially directed flange disposed in said annular groove and a neck portion in said slot and interconnecting said flange and said seal face;
• certain of said plurality of packing ring segments being movable between radial outward and radial inward positions relative to said axis, including a lower side segment defining a lower side one of a plurality of annular segments about the axis of the machine;
• said lower side segment having upper and lower circumferential ends and a length so as to extend circumferentially beyond, so that said upper circumferential end is disposed vertically above, said horizontal midline joint of said stationary component;
• and
• a key bar member secured to said stationary component and projecting generally radially inwardly therefrom for engagement with a key bar receptacle defined in a radially outer surface of said lower side segment body, adjacent said upper circumferential end, for preventing downward circumferential displacement of the lower side segment body in the annular groove.

A method of mounting a variable clearance positive pressure packing to a stationary component of a rotary machine having a component rotatable about a rotary axis, the stationary component having an annular groove about the axis, at least one axially directed locating flange about the axis and in part defining a slot opening into the annular groove, the stationary component being defined by upper and lower half housing parts secured to define a horizontal midline joint, the method comprising the steps of:

• providing a lower side segment body for forming a lower side segment one of a plurality of annular segments about the axis of the machine, said lower side segment body having upper and lower circumferential ends, an arcuate seal face, at least one axially directed flange for disposition in the annular groove, a neck portion receivable in the slot and interconnecting said flange and said seal face;
• partially disposing said lower side segment body in the annular groove of the stationary component by slidably engaging said at least one axially directed flange with said annular groove, said lower side segment body having a length so as to extend circumferentially beyond, so that said upper circumferential end is disposed vertically above, said horizontal midline joint of said stationary component;
• engaging a key bar member with a key bar receptacle defined in a radially outer surface of said lower side segment body, adjacent said upper circumferential end;
• and
• securing said key bar member to said stationary component to prevent downward circumferential displacement of the lower side segment body in the annular groove.