Side entry sub

A side entry sub, comprising:

• an elongated main body comprising a longitudinal bore therethrough, said longitudinal bore forming a wall in said main body, said main body further comprising a side passage extending through said wall and intersecting said longitudinal bore, said side passage comprising internal threads therein;
• a removable hub comprising a longitudinal bore therethrough, forming a flowpath through said removable hub and into said longitudinal bore of said main body when said removable hub is threadably engaged with said main body, wherein said removable hub further comprises a nose portion comprising threads engageable with said internal threads in said side passage and a seal groove, an outermost end comprising external threads, and a flange positioned between said nose portion and said outermost end;
• a resilient seal element positioned in said seal groove and sealing between said main body and said removable hub, when said removable hub is threadably engaged with said main body;
• and
• wherein, when said removable hub is fully threadably engaged with said main body, said flange is in contact with said main body, and one or more fasteners are positioned through holes in said flange and into said main body, thereby preventing rotation of said removable hub.