Abstract: A method for circulating and maintaining a drilling mud in a wellbore drilled into a subterranean formation at a desired pressure during drilling operations, said method consisting essentially of;(a) circulating drilling mud through a drill pipe in the wellbore into the wellbore, maintaining a desired pressure in said wellbore and recovering drilling mud from the wellbore at a controlled rate using a mud pump and mud pit arrangement; and,(b) maintaining a second supply of drilling mud in fluid communication with the drill pipe at a suitable pressure so that when the mud pump fails to maintain pressure in the drill pipe, drilling mud is supplied from the second supply of drilling mud to maintain pressure in the wellbore.

Abstract: A carrier for a plurality of transducers is disclosed. The carrier is useful in ultrasonic testing of furnace tubes. The carrier includes provision for positioning a plurality of transducers against the interior of the tubes.

Abstract: A roll straightener for wire is disclosed in which rolls on each side of the wire are mounted in fixed spatial relation in supports and the relative positioning of the supports is adjusted, depending on wire type and size, to produce straightened wire.