Patent ID: 9238965
Filing Date: 2016-01-19
CPC Classification: E21B

Claim Text:
1. A rotary pulser for transmitting information from a portion of a drill string operating at a down hole location in a well bore, said drill string having a passage through which a drilling fluid flows, comprising: a) a stator adapted to be mounted in said drill string and having at least one passage formed therein through which at least a portion of said drilling fluid flows; b) a rotor adapted to be mounted in said drill string proximate said stator, said rotor being rotatable into at least first and second circumferential orientations, said rotor imparting a different degree of obstruction to said flow of drilling fluid flowing through said stator passage depending on the circumferential orientation of said rotor, said first circumferential orientation providing a greater obstruction to said flow of drilling fluid than that of said second rotor circumferential orientation, whereby rotation of said rotor generates 1) a pressure drop in said drilling fluid across said rotor, and 2) as a series of pulses encoded with said information to be transmitted; c) a gap formed between said rotor and said stator, rotor and stator capable of relative displacement with respect to each other during rotation of the rotor, wherein displacement of said rotor toward said stator reduces said gap, and displacement of said rotor away from said stator increases said gap; and d) a spring arranged so that deflection of said spring generates a biasing force resisting relative displacement between said rotor and said stator.