| 20110240375 | DOWNHOLE APPARATUS - A double-acting compounder is disclosed, comprising: an outer housing; an inner mandrel at least partially disposed telescopically within the outer housing to define a fluid chamber between the inner mandrel and the outer housing, the fluid chamber containing fluid and being sealed at an uphole end and a downhole end; an equalizer between the fluid chamber and an exterior of the outer housing for equalizing pressure; a movable seal assembly disposed within the fluid chamber and having a first end that defines the uphole end or the downhole end of the fluid chamber; the inner mandrel having an outer shoulder for contacting a second end of the movable seal assembly to move the movable seal assembly with the inner mandrel when the inner mandrel moves in a first direction relative to the outer housing to compresses fluid within the fluid chamber; and the outer housing having an inner shoulder for contacting the second end of the movable seal assembly to prevent the movable seal assembly from moving with the inner mandrel when the inner mandrel moves in a second direction relative to the outer housing to compresses fluid within the fluid chamber. The equalizer may comprise an equalization piston, and the double-acting compounder may comprise a restrictor for restricting initial movement of the movable seal assembly from both the inner shoulder and the outer shoulder due to hydrostatic pressure when the double-acting compounder is in a neutral position. The restrictor keeps the movable seal assembly from moving first and allows the equalizer piston to move and establish hydrostatic pressure in the fluid chamber. Thus, the movable seal assembly is kept in a neutral position and full stroke up and down is preserved, making the tool more efficient relative to a compounder without such an equalizer. | 10-06-2011 |
