Back pressure valve with double barrier sealing

A back pressure valve for providing a double barrier to flow for use within a tubing hanger within a well bore, the back pressure valve comprising:

• a. a cylindrical two-piece body with a bore hole therethrough, wherein the cylindrical two-piece body comprises a first body piece engaged with a second body piece, and wherein the cylindrical two-piece body comprises a body sealing surface for sealing between the first body piece and the second body piece;
• b. a first pressure piston disposed within the bore hole, wherein the first pressure piston is configured to sealingly engage a first sealing surface in the second body piece, and wherein the first pressure piston with the first sealing surface seals bottom pressure from the well bore, providing a first barrier to flow;
• c. a first moving stem engaged with a first compression spring, wherein the first moving stem has a first stem first end engaged with the first pressure piston for holding the first pressure piston in a first position relative to the cylindrical two-piece body, and wherein the first moving stem is configured to align the first pressure piston with the second body piece, and wherein the first moving stem has a first stem second end disposed through a centralizer alignment hole;
• d. a second pressure piston disposed within the bore hole, wherein the second pressure piston is configured to sealing engage a second sealing surface in the first body piece, and wherein the second pressure piston with the second sealing surface seals bottom pressure from the well bore, providing a second barrier to flow;
• e. a second moving stem engaged with a second compression spring, wherein the second moving stem has a second stem first end engaged with the second pressure piston for holding the second pressure piston within the bore hole and in alignment with the second sealing surface;
• f. a guide plate disposed within the bore hole and engaged between the first body piece and the second body piece for receiving a second stem second end and centralizing the second moving stem in the cylindrical two-piece body, wherein the guide plate comprises a plurality of flow passageways;
• and
• g. a plurality of stabilizer legs, wherein each stabilizer leg of the plurality of stabilizer legs is connected to the second body piece at one end and to the centralizer alignment hole opposite the second body piece, and wherein the first moving stem is engaged within the centralizer alignment hole.