Stripper blow out preventer for small diameter oil field tubing or small diameter polished rods

A stripper blow out preventer for small diameter oil field tubing or small diameter polished rods, wherein the stripper blow out preventer comprises:

• a. a housing with a longitudinal bore for engaging oil field work over equipment or oil field stimulation equipment;
• b. an open port in the housing for accepting hydraulic fluid;
• c. a close port in the housing for accepting the hydraulic fluid;
• d. a grease port in the housing for allowing grease to lubricate housing threads in the housing;
• e. a dual diameter annular recess having a first diameter differing from a second diameter, wherein the dual diameter annular recess is in fluid communication with the longitudinal bore;
• f. a dual threaded retainer ring threadably engaged in the dual diameter annular recess comprising:
• inner threads, outer threads, and a beveled seal surface, wherein the outer threads are engaged with the housing threads;
• g. a piston with a piston beveled seal surface, wherein the piston is disposed in the dual diameter annular recess;
• h. a radially expandable resilient seal element with a resilient seal element top beveled seal surface and a resilient seal element bottom beveled seal surface, wherein the radially expandable resilient seal element is disposed in the dual diameter annular recess, wherein the resilient seal element bottom beveled seal surface is engaged with the piston beveled seal surface, and wherein the radially expandable resilient seal element has a thru bore with a diameter identical with the diameter of the oil field work over equipment or oil field stimulation equipment;
• i. a replaceable insert threadably engaged with the inner threads of the dual threaded retainer ring, wherein insert threads located on an upper portion of the replaceable insert are engaged with the inner threads of the dual threaded retainer ring, and a beveled lower portion is engaged with the resilient seal element top beveled seal surface, and wherein the replaceable insert is configured to accommodate oil field equipment within the housing having different diameter sizes;
• j. a plurality of first seals disposed between the first diameter of the dual diameter annular recess and the piston;
• k. a second seal disposed between the dual threaded retainer ring and the replaceable insert;
• l. a third seal disposed between the dual threaded retainer ring and the housing;
• m. a fourth seal disposed between the dual threaded retainer ring and the piston;
• and
• n. a plurality of fifth seals disposed between the piston and the housing, wherein when the close port is pressurized by hydraulic fluid the piston is configured to move axially in a first direction in the longitudinal bore and press against the radially expandable resilient seal element to form a high pressure seal against the oil field work over equipment or oil field stimulation equipment in the longitudinal bore, and wherein when the open port is pressurized by hydraulic fluid the piston is configured to move axially in a second direction opposite the first direction to relax the radially expandable resilient seal element from the oil field work over equipment or oil field stimulation equipment in the longitudinal bore.