Patent ID: 7255164

Claim:
A casing brush assembly comprising: a mandrel; and a brush mounted on the mandrel, the brush comprising an upper collar, a lower collar and a plurality of elongate brush elements extending between the upper and lower collars, each brush element having an inner surface radially spaced from the underlying mandrel and a central region having a plurality of wire bristles on the radially outer surface thereof, wherein the brush is flexible such that, in use, if the brush is forced through a zone of casing of reduced inside diameter the brush elements will flex radially inwardly to reduce the bending load on the bristles before the bristles plastically deform, break, or are unseated from the brush elements, wherein each brush element comprises a body having a central region to which the bristles are mounted, wherein the upper collar, the brush element bodies and the lower collar are a unitary structure, and wherein the radial wall thickness of the material making up the collars and the central regions of the brush element bodies is greater than the corresponding radial wall thickness of the portions of the brush element bodies which lie between the central regions and the collars whereby radial flexing of the brush element bodies is largely accommodated by the relatively thin-walled portions of the brush elements located between the central regions and the collars.