Down hole drilling motor with lobed stator of nitrile rubber

• Main Author: LILLIAN GUO
• Format: Patent
• Language: English
• Published: 24.09.2003
• Edition: 7
• Subjects: BLASTING; HEATING; INDEXING SCHEME RELATING TO MATERIALS, MATERIAL PROPERTIES ORMATERIAL CHARACTERISTICS FOR MACHINES, ENGINES OR PUMPS OTHERTHAN NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES; INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUSSUBCLASSES OF CLASSES F01-F04; LIGHTING; MACHINES OR ENGINES FOR LIQUIDS; MECHANICAL ENGINEERING; OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR; POSITIVE DISPLACEMENT MACHINES FOR LIQUIDS; POSITIVE-DISPLACEMENT ENGINES DRIVEN BY LIQUIDS; PRODUCING MECHANICAL POWER; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENTMACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENTPUMPS; WEAPONS; WIND, SPRING WEIGHT AND MISCELLANEOUS MOTORS

The down hole drilling motor, eg of the progressing cavity or Moineau type, comprising a tubular housing 12, eg of steel, enclosing a lobed stator 20 of nitrile rubber which defines a cavity 34 within which a lobed rotor 22 is caused to rotate by applying fluid pressure to the cavity 34. The stator 20 may be formed from a compound comprising nitrile rubber having about 35% by weight acyrlonitrile, a Mooney viscosity of about 50 (35-5 NBR) and a hardness of less than 90 Shore A. Various other structural properties of the compound including tensile strength, elongation at break, tear strength, tensile modulus, compression modulus, E', E'' and tan s are specified. The stator compound has improved manufacturing and performance characteristics.