Apparatus for Stripping Fluid from Well Pipe (Patent No: 944685)

Inventor: Brown, William H.

Location: Edmonton

Comments: N/A

Description: The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. In a wiper device for stripping fluid from the outer surface of a well string, which device comprises a container having side walls, a pair of horizontal wiper pads disposed within the container and slidable horizontally between an open position, wherein they are disassociated from the well string, and a closed position, wherein they press against the well string, the improvement which comprises: a container having side walls which are outwardly spaced from the sides of the wiper pads to permit of lateral movement of the pads therewithin; at least one cylinder assembly mounted on and linking the wiper pads for opening and closing them; flexible means, connected to the cylinder assembly, for supplying operating fluid to it; and means for supplying operating fluid to the flexible means.

2. The improvement as set forth in claim 1 wherein: the cylinder assembly is double-acting and has a piston working within a barrel; and the flexible means comprises two flexible conduits, one connected into each end of the barrel.

3. The improvement as set forth in claim 2 wherein the means for supplying operating fluid comprises: a source of pressurized air; first and second air lines, each connecting the source with one of the flexible conduits; and accumulator means in the first air line for receiving air, displaced from the cylinder assembly due to the passage of an enlargement through the wiper pads, and maintaining the pressure substantially constant within the cylinder assembly.

4. A wiper device for use in conjunction with a rig working on a well, said device being adapted to strip fluid from the outer surface of the well string as it is pulled from the well, comprising a container adapted to be mounted on the wellhead, said container having top, bottom and side walls with aligned openings formed in the top and bottom walls for accomodating the passage therethrough of a well string; a pair of wiper pads arranged in horizontal, overlapping, longitudinally movable relationship within the container, said pads being inwardly spaced from the side walls and being slidable between an open position, wherein they are disassociated from the well string, and a closed position, wherein they press against the well string or overlap to form a closure should the well string be out of the well, each said pad having an elastic, resilient block defining a string conforming opening in its inner edge; first means, connected to the two wiper pads, adapted, when subjected to a closing force, to bias them to the closed position, said first means comprising a cable, a plurality of sheaves, and a movable member disposed outside the container, one said sheave being mounted within the container and secured thereto, another said sheave being mounted on the movable member, said cable being attached at one end to one
wiper pad and at the other end to the other wiper pad, said cable further passing over the container and movable member sheaves whereby, when the well string sways laterally within the container, the wiper pads are both caused to float with it; and second means, connected to the first means, adapted to supply a closing force of selected intensity to them, said second means comprising a spring and cable combination connected at one end to the movable member, and means connected to the said combination at its other end, said means being adapted to supply the said closing force.