Plug valve having preloaded seal segments

A plug valve comprising:

• a valve body having an inlet port, an outlet port and a central chamber extending between the inlet port and the outlet port;
• an inlet and an outlet seal segment disposed within the central chamber proximate the inlet and outlet ports, respectively, each having a bore extending therethrough and coaxially aligned with valve body inlet and outlet ports;
• a plug member disposed in the central chamber, the plug member moveable between an open position, to facilitate fluid flow through the plug valve, and a closed position, to block fluid flow through the plug valve;
• and
• at least one side segment extending less than halfway around a perimeter of the plug member, the side segment having ends nestable with respective ends of the inlet and outlet seal segments to interlock the at least one side segment to the inlet and outlet seal segments, the at least one side segment and the seal segments encircle the plug member such that the at least one side segment is tensioned to preload and tension the seal members against the plug to form a seal between the plug and the seal segments to prevent the flow of fluid between the seal segments and the plug member.

A method of manufacturing a plug valve, comprising:

• forming a valve body having an inlet port, an outlet port and a central chamber extending between the inlet port and the outlet port;
• inserting an inlet seal segment and an outlet seal segment within the central chamber proximate the inlet and outlet ports, respectively, such that respective bores extending through the inlet and outlet ports are coaxially aligned with valve body inlet and outlet ports;
• inserting at least one side segment between respective ends of the inlet and outlet seal segments, the at least one side segment having ends nestable with respective ends of the inlet and outlet seal segments to interlock the at least one side segment to the inlet and outlet seal segments, the at least one side segment and the seal segments configured to encircle and form a plug receiving area having an inner diameter;
• and
• tensioning the at least one side segment by inserting a plug member having an outer diameter sized larger than the receiving area inner diameter to create a pulling force thereby preloading the inlet and outlet seal members against the plug to form a seal between the plug and the seal segments.

A seal assembly for a plug valve including a valve body having an inlet port, an outlet port and a central chamber extending between the inlet port and the outlet port, a plug member disposed in the central chamber, the plug member moveable between an open position, to facilitate fluid flow through the plug valve, and a closed position, to block fluid flow through the plug valve, the seal assembly comprising:

• an inlet seal segment disposed within the central chamber and having a bore extending therethrough and aligned with the inlet port;
• an outlet seal segment disposed within the central chamber having a bore extending therethrough and aligned with the outlet port;
• and
• a first side segment and a second side segment detached and spaced apart from the first side segment, the first and second side segments having ends nestable with and interlocking to respective ends of the inlet and outlet seal segments, the first and second side segments and inlet and outlet seal segments encircle the plug member and are sized, relative to the plug member, to tension the side segments and seal members against the plug to form a seal between the plug and the seal segments.