GB2469669A

GB2469669A - Frangible ceramic bearing

Info

Publication number: GB2469669A
Application number: GB0906947A
Authority: GB
Inventors: Edward Docherty Scott
Original assignee: Individual
Current assignee: Individual
Priority date: 2009-04-23
Filing date: 2009-04-23
Publication date: 2010-10-27
Also published as: GB0906947D0

Abstract

Drillable drilling motor bearing with a ceramic wafer layer 3 which is pre weakened enabling it to be mechanically destroyed and removed from a borehole. The frangible bearing has a thin ceramic layer 3 bonded to a substructure 1. Stressed lines of weakness 4 can assist the destruction of the bearing. The ceramic layer can have a pore structure or perforations 5 to create a reservoir for a lubrication fluid. The stress lines and perforations can be made by laser.

Description

Title: Thin Layer Ceramic Bearing, Application: Rotating and Sliding Interface Bearing or Sealing Equipment General: One example of the application is set out in the following paragraph.

In the process of drilling weilbores for the extraction of hydrocarbons and geothermal energy one method of achieving this is utilising hydraulic drilling motors where there are a variety of machines constructed for this purpose. Typically these machines are positive displacement, turbine, vane and electric motors in addition there is the recent development of rotary stearable systems, all of these systems require both radial and axial thrust bearing.

The technology of preparing thrust and radial bearings from elastomers, ball thrust bearings, Polycrystalline (PCD) or polymer thrust bearings are reasonably well developed.

It would be well understood by those skilled in the art of mechanical engineering that this bearing application can be equally applied to any rotating or sliding bearing system.

In the development of a drillable motor system as described in our Patent number CTIGB/2007/002874 Running Bore-I ining Tubulars' in the name of "Futuretec-Ltd" there is presented an engineering challenge to provide a high speed thrust bearing which can be drilled through using standard existing rotary drill PDC bits. All existing drilling Motors are furnished with Radial & Thrust Bearing systems which due to the nature of their construction are considered to be non-drillable.

The following description sets out a patent proposal for a fully through drillable Thrust and or Radial bearing element.

A Ceramic wafer plate of thickness of appx 0.75 -1.0mm or more or less thickness is constructed from a ceramic which can be stressed or perforated by laser beam energy technology application, this technology being well developed by leading ceramic industry suppliers, these lines of stress may be of a geometric regular construction which facilitates easy fracture of the ceramic plate into small pieces by the application of impact force. The ceramic may also be perforated by the application of laser energy technology, these perforations facilitate a reservoir of lubrication fluid to be contained and thereby provide a stored lubrication boundary between mating sliding layers of ceramic or ceramic and another sliding structure of different materials.

The bearing is constructed by metalising a surface of the ceramic wafer and bonding by typically high strength brazing or laser welding to a substructure which is not ceramic or e.g. carbide or softer metals. The ceramic wafer may alternatively be bonded by the application of industrial adhesive sufficient in strength to resist any shearing action when two bearing / sliding surfaces run against each other.

Fig 1; Shows a general layout of a Ceramic Rotating Seal and substructure, item I shows the substructure, item 2 points to the bond plane, item 3 shows the Ceramic wafer, item 4 shows the laser scored lines of stress structure item 5 shows the laser applied perforations which create the lubrication reservoir.

Fig 1: only shows one side of a sealing component, it is to be understood that a mating component of similar geometry with both sliding surfaces in contact will constitute the bearing contact sliding faces.

It is understood that this method of construction can be applied to any geometrical form of supporting substructure e.g., flat rings, flat forms or can be constructed as thin section annular rings or other geometrical forms which may constitute the construction of a bearing system.

Claims

Claims: 1) A method of constructing a thin wafer ceramic bearing which has the facility to be mechanically broken up and destroyed for the purpose of flushing i.e. circulating out' from a well bore if required.
2) A method of constructing a bearing structure which is bonded to a mechanically resilient supporting sub-structure.
3) A method of constructing a bearing where the bearing component of the assembly has had laser beam energy technology applied to the surface of the structure where this application sets up small but geometrically constant discrete areas of stressed lines of weakness to assist in the process of fracture by drill through of the bearing system.
4) A method of constructing a bearing material which has had laser beam energy application to generate a micro-pore structure at the sliding surface of the bearing contact face. This micropore structure creating a reservoir of lubrication fluid to aid the lubrication between sliding surfaces.
5) A method of bonding by metalising a surface of the Ceramic to be bonded to a supporting substructure sufficient to resist shear forces.
6) A method of constructing a bearing assembly by bonding chemically with industrial adhesive a wafer of ceramic to a substructure of a different material.
7) A method of constructing a bearing which may be a plain thrust bearing or a radial journal bearing or a bearing surface of a convex or concave or irregular shape.
8) A bearing assembly constructed from different materials, these being Ceramics e.g. Silicon Carbide and softer than ceramic i.e. metals or other materials.
9) A bearing assembly where the bearing surface being finished lapped / polished has a typical coefficient of friction approaching 0,1 or 0,05 or better.