Patent ID: 8813849

Claim:
An oil well safety shut off method, comprising the steps of: a) providing in a section of well casing having a well bore, a device having a first flow bore of a first diameter aligned generally with the well bore of the casing so that flow through the casing also flows through the first flow bore; b) providing a second flow bore that communicates with the first bore at two spaced apart positions to provide a lower flow entry from the first flow bore and an upper flow discharge into the first flow bore, the second flow bore having a diameter that is at least in part larger in transverse cross section than the first diameter; c) providing an upper ball seat in the first flow bore and above the upper flow discharge; d) providing a lower ball seat in the second flow bore in between the lower flow entry and the upper flow discharge; e) placing a ball valving member in the second flow bore above the lower seat; f) disallowing entry of the ball valving member into the first flow bore by placing a ball retarding member in the first flow bore, the ball retarding member occupying a position within the first flow bore and extending above and below the upper flow discharge; and g) a removal of the ball retarding member enabling the ball valving member to form a seal with the upper ball seat, slowing the flow of fluids upwardly in the first flow bore.