Plug valve and stem sealing assembly

A self-adjusting stem seal assembly for a plug valve having a body with a first port, a second port and a passage configured to flow a media extending between said first port and said second port, a flow-element positioned between said first port and said second port, wherein said flow-element has a stem configured to actuate said flow-element between a closed position and an open position and a bonnet secured to said body, wherein said stem seal assembly is adjacent to said stem and is configured to prevent media leakage from the valve, said stem seal assembly comprising:

• a. a primary seal seated in an annular space defined by the area between said stem, said body and said bonnet, said primary seal comprising:
• i. a primary sealing component comprising;
• a bottom sealing element:
• a top sealing element,
• ii. a primary force transmitting component, wherein said primary force transmitting component comprises a primary force transmitting surface and a primary force transmitting member configured to transfer a first axial load to said primary force transmitting surface, wherein said primary force transmitting surface is configured to transfer said first axial load to said bottom sealing element and said top sealing element to create a seal between the said body and said stem;
• b. a secondary seal comprising:
• i. a packing configured to expand radially to form a seal with said stem;
• ii. a secondary force transmitting component, wherein said secondary force transmitting component comprises a secondary force transmitting surface;
• and a secondary force transmitting member configured to transfer a second axial load to said secondary force transmitting surface, wherein said secondary force transmitting surface is configured to transfer said second axial load to said packing thereby creating a seal between said stem and said primary seal;
• and
• c. a tertiary seal.

A plug valve comprising:

• a. a body having a first port and a second port with a passage configured to flow a media extending between said first port and said second port;
• b. a flow-element positioned between said first port and said second port, wherein said flow-element has a stem configured to actuate said flow-element between a closed position and an open position;
• c. a stem sealing assembly configured to prevent media leakage from the valve, said stem sealing assembly comprising:
• i. a primary seal comprising:
• a bottom sealing element;
• a top sealing element;
• a primary force transmitting surface;
• a primary force transmitting member configured to transfer a first axial load to said primary force transmitting surface, wherein said primary force transmitting surface is configured to transfer said first axial load to said bottom sealing element and said top sealing element to create a seal between said body and said stem;
• ii. a secondary seal;
• iii. a tertiary seal;
• and
• d. a bonnet secured to said body.