Well drilling apparatus

Claim 1

IN A STRUCTURE FORMING A PASSAGE CONFINING A FLUID STREAM, THE COMBINATION OF: TWO SECTIONS OF THE STRUCTURE TELESCOPED TOGETHER FOR LONGITUDINAL MOVEMENT RELATIVE TO EACH OTHER; A RESTRICTION IN THE PASSAGE CARRIED BY ONE OF THE TWO SECTIONS; A CHOKE HEAD CARRIED BY THE OTHER SECTION AND NORMALLY SPACED FROM THE RESTRICTION LONGITUDINALLY OF THE PASSAGE; MEANS TO SENSE A CONDITION; MEANS RESPONSIVE TO SAID SENSING MEANS TO CAUSE LONGITUDINAL MOVEMENT BETWEEN THE TWO SECTIONS THEREBY TO CAUSE RELATIVE MOVEMENT OF THE RESTRICTION AND THE CHOKE HEAD TOWARDS EACH OTHER TO CREATE A SIGNALING PRESSURE RISE IN THE STREAM BY PROGRESSIVELY RESTRICTING THE STREAM WITH PROGRESSIVE INCREASE IN THE LOCAL VELOCITY OF THE STREAM; AND MEANS TO ACCELERATE THE RELATIVE MOVEMENT BETWEEN THE CHOKE HEAD AND THE RESTRICTION IN RESPONSE TO THE RISE IN VELOCITY THEREBY TO INCREASE THE RATE OF PRESSURE RISE.