A casing brush assembly comprises a mandrel, upper and lower stabilisers, a brush and a magnet assembly. The magnet assembly comprises a plurality of helically extending brush elements each of which is spaced from the underlying mandrel so that it can flex inwardly to accommodate variations in casin
A casing brush assembly comprises a mandrel, upper and lower stabilisers, a brush and a magnet assembly. The magnet assembly comprises a plurality of helically extending brush elements each of which is spaced from the underlying mandrel so that it can flex inwardly to accommodate variations in casing diameter. The thickness of the brush elements is relatively thin in the portions which connect the central regions to the ends of the brush with the result that the deflection of the brush elements is largely accommodated by the relatively thin regions. The magnet assembly includes three rings of magnets held in a non-magnetic cage and located beneath a thin cover of non-magnetic material. The assembly can be used in a non-rotating mode (in which the brush is free to rotate relative to the mandrel) or in a rotating mode in which the brush is rotationally fast with the mandrel.
대표청구항▼
The invention claimed is: 1. 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 r
The invention claimed is: 1. 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. 2. A casing brush assembly according to claim 1, wherein each brush element is part helical over at least some of its length and the brush elements, when viewed axially of the tool, provide a circumferentially continuous brushing area. 3. A casing brush assembly according to claim 2, wherein each brush element is part helical over the central region thereof and the end regions of each brush element (that is the regions between the central region and the respective collars) is substantially completely axially extending relative to the tool axis. 4. A casing brush assembly according to claim 1, having stabilisers at both ends of the brush. 5. A casing brush assembly according to claim 4, wherein the stabilisers are mounted on the mandrel by one or more ballbearings which locate the stabilisers on the mandrel and transmit thrust load from the stabilisers to the mandrel. 6. A casing brush assembly according to claim 5, wherein the magnets are located relative to each other by a non-magnetic cage. 7. A casing brush assembly according to claim 1, including, in addition to the brush and mandrel, at least one magnet assembly. 8. A casing brush assembly according to claim 7, wherein the at least one magnet assembly is provided on one side only of the brush to attract any iron or steel debris removed by the brush as the tool is moved in the direction in which the at least one magnet assembly is at the trailing end of the brush. 9. A casing brush assembly according to claim 7, wherein the at least one magnet assembly is provided on both sides of the brush. 10. A casing brush assembly according to claim 1, wherein at least one of the brush and magnet assemblies are mounted on the mandrel for free rotation relative to the mandrel. 11. A casing brush assembly according to claim 10, wherein means are provided for optionally locking the brush relative to the mandrel so that the casing brush assembly may be used in a rotating mode. 12. A casing brush assembly according to claim 11, having stabilisers at both ends of the brush, wherein the stabilisers are mounted on the mandrel by one or more ballbearings which locate the stabilisers on the mandrel and transmit thrust load from the stabilisers to the mandrel, and wherein the locking means comprises a locking ring threadedly mounted on the mandrel and movable to apply axial thrust load on one of the stabilisers. 13. A casing brush assembly according to claim 10, wherein radially inward of the magnets, is a sleeve of magnetic alloy whilst radially outwardly of the magnets is a thin sleeve of non-magnetic material. 14. A casing brush assembly according to claim 7, wherein the or each magnet assembly comprises three longitudinally adjacent circumferentially extending rings of magnets with all the poles of the top and bottom rings of magnets are oriented so that the same pole is facing radially outwardly. 15. A casing brush assembly according to claim 14, wherein all the magnets of the middle ring are orientated so that the pole which is opposite to the outwardly facing poles of the upper and lower rings is facing radially outwardly. 16. A casing brush assembly according to claim 14, wherein the magnets of the middle ring are circumferentially staggered from the magnets of the upper and lower rings. 17. A casing brush assembly according to claim 14, wherein the magnets are located relative to each other by a non-magnetic cage. 18. A casing brush assembly according to claim 7, wherein radially inward of the magnets, is a sleeve of magnetic alloy whilst radially outwardly of the magnets is a thin sleeve of non-magnetic material. 19. A casing brush assembly according to claim 1, wherein the brush has means formed at the longitudinally opposite extremities thereof for engaging mating means on adjacent components of the casing brush assembly to prevent rotation of the brush relative to the adjacent components. 20. A casing brush assembly according to claim 1, comprising upper and lower stabilisers, one or more brushes, and one or more magnet assemblies, all of which components are provided with means to enable the entire assembly of components to be locked together for rotation as a single unit. 21. A casing brush assembly according to claim 20, wherein a ring nut is mounted on the mandrel with a castellated end region for selectively engaging a complementary castellated end region of one of the stabilisers in order to lock the stabiliser (and accordingly any components rotationally fast with the stabiliser) against rotation relative to the mandrel. 22. A casing brush assembly according to claim 1, wherein at least one of the brush and magnet assemblies are radially located relative to the mandrel by components located opposite ends of the brush and magnet assemblies and a working clearance is provided between the brush and magnet assemblies and the mandrel. 23. A casing brush assembly according to claim 22, wherein the brush is located radially at least one end thereof by a magnet assembly.
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이 특허에 인용된 특허 (5)
Hammon Donald P. (75 E. Mountain View St. Long Beach CA 90805), Brush tool for wells.
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