| 摘要 |
A pipe recovery circulation valve for open hole drilling, which includes a valve body attachable intermediate sections of drill string for normally allowing flow therethrough to the drill bit. The valve further includes a fluid flow means where upon activation directs fluid flow exterior to the valve body, a first main sleeve slideable within the bore of the valve body moveable between a first position wherein the fluid flow means prevents fluid flow exterior to the valve body; and a second position wherein the fluid flow means is activated to allow flow exterior to the valve body. An upper retainer sleeve is fixed within the valve body, which includes a spring for allowing the main sleeve to move between the first and second positions against the bias of the spring. A spring loaded detent pin is provided for maintaining a main sleeve in the second position for allowing fluid flow exterior to the valve body. An unlocking sleeve, slideable within the valve body cooperates with an arm member to disengage the detent pin for allowing the main sleeve to shift into the first position for preventing fluid flow exterior to the valve body. The main sleeve and unlocking sleeve are activated by a wireline tool lowered within the tool during operation. There is further provided a guard sleeve contained within the lower portion of the valve body for guarding functioning of the fluid flow means during operation.
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