A connection apparatus. The apparatus comprises a wing mandrel having a first check valve disposed within an inner bore of the wing mandrel, a thread mandrel abutting the wing mandrel, with the thread mandrel having outer threads and a second check valve disposed within an inner bore of the thread mandrel....http://www.google.es/patents/US7789100?utm_source=gb-gplus-sharePatente US7789100 - Connection apparatus and method
