(19)
(11) EP 0 136 146 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
20.01.1988 Bulletin 1988/03

(43) Date of publication A2:
03.04.1985 Bulletin 1985/14

(21) Application number: 84306365

(22) Date of filing: 18.09.1984
(84) Designated Contracting States:
DE FR GB IT NL

(30) Priority: 19.09.1983 US 533835
19.09.1983 US 533701
19.09.1983 US 533901
19.09.1983 US 533834

(71) Applicant: HALLIBURTON COMPANY
 ()

(72) Inventor:
  • Beck, Harold Kent
     ()

   


(54) Annulus pressure responsive downhole tool


(57) An annulus pressure responsive downhole tool includes a housing (54) having a power piston (140) slidably disposed therein. First (160) and second (166) pressure conducting passages communicate a well annulus (42) with first (142) and second (144) sides of the power piston. A retarding device (244) is disposed in the second pressure conducting passage for delaying communication of a sufficient portion of an increase in well annulus pressure to the second side of the power piston for a sufficient time to allow a pressure differential across the power piston to move the power piston from a first position to a second position relative to the housing. A pressure relief means (272) is communicated with the second pressure conducting passage between the power piston and the retarding device for relieving from the second pressure conducting passage a volume of fluid sufficient to permit the power piston to travel to its second position.






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