Claims
- 1. In a drill bit having a main body and means at an upper end thereof for attachment to a driving means; a drilling face formed at the lower end of said main body, drilling cutters secured to and forming part of said face; a throat formed through said main body; said throat having a fluid outlet connected thereto for passage of drilling fluid to said face;
- said fluid outlet contains a flow restricting means arranged to provide first a constricted flow and serially thereafter a diffused flow, thereby producing a reduced fluid velocity onto said face;
- said flow restricting means includes a first nozzle stage that is shaped, sized, and arranged to provide a combination of effectual fluid flow constriction and diffused fluid flow, an intermediate nozzle stage shaped, sized, and arranged to provide a combination of minimal fluid flow constriction and optimum diffused fluid flow, and an outlet nozzle stage shaped, sized, and arranged to provide a combination of minimal fluid flow constriction and substantially straightened fluid flow.
- 2. A rotary drill bit comprising: a main body having means at an upper end thereof for attachment to a driving means; a drilling face formed at the lower end of said main body, drilling cutters secured to said face; a throat formed through said main body; fluid outlet means connected to said throat for passage of drilling fluid to said face; said fluid outlet means contains a flow restricting means arranged to provide first an effectual constricted flow then, serially thereafter, a diffused flow initiated within said restricting means and thereafter a fluid discharge of reduced constriction;
- said flow restricting means is positioned in the fluid path of said throat, and is arranged to provide a fluid pressure drop onto said face;
- said flow restricting means includes; a first nozzle stage shaped, sized, and arranged to provide a combination of effectual fluid flow constriction and diffused fluid flow; an intermediate nozzle stage shaped, sized, and arranged to provide a combination of minimal fluid flow constriction and optimum diffused fluid flow; and an outlet nozzle stage shaped, sized, and arranged to provide a combination of minimal fluid flow constriction and practically straightened fluid flow.
- 3. A drill bit as in claim 2 which includes a flow isolating ridge means secured to said face, said ridge means being of sufficient height to contact the bottom of a borehole during drilling operation.
- 4. A drill bit as set forth in claim 3 wherein said ridge means substantially seals both sides and one end of said isolated flow path.
- 5. A drill bit as in claim 2 wherein said flow restricting means provides first a constricted flow then serially a fluid flow of reduced velocity onto said face.
- 6. A drill bit as in claim 2 wherein said flow restricting means includes serially arranged nozzle stages.
- 7. In a rotary drill bit having a generally cylindrical main body and means at an upper end thereof for attachment to a driving means; a drilling face formed at the lower end of said main body, drilling cutters secured to said face; a throat formed through said main body; said throat having a fluid outlet connected thereto for passage of drilling fluid to said face; the improvement comprising:
- said fluid outlet contains a flow restricting means arranged to provide first a constricted flow then, serially thereafter, within said restricting means a diffused flow and thereafter a reduced fluid velocity onto said face;
- said flow restricting means is positioned in the fluid path of said throat, said flow restricting means being arranged to provide a fluid pressure drop onto said face;
- said flow restricting means includes; a first nozzle stage shaped, sized, and arranged to provide a combination of effectual fluid flow constriction and diffused fluid flow; an intermediate nozzle stage shaped, sized, and arranged to provide said diffused fluid flow; and an outlet nozzle stage shaped, sized, and arranged to provide minimal fluid flow constriction.
- 8. A drill bit as in claim 7 which includes a flow isolating ridge means secured to said face and of sufficient height to contact the bottom of a borehole during drilling operation.
- 9. A drill bit as in claim 8 wherein said ridge means practically seals both sides and one end of an isolated flow path formed by said flow isolating means.
- 10. A drill bit as in claim 7 wherein said flow restricting means provides first a constricted flow then serially a fluid flow of reduced velocity onto said face.
- 11. A drill bit as in claim 7 wherein said flow restricting means includes serially arranged nozzle stages.
REFERENCE TO RELATED PATENT APPLICATION
This patent application is a continuation of patent application Serial No. 07/076,910 filed July 23, 1987 now abandoned, which in turn is a continuation of application Serial No. 06/820,742, filed Jan. 22, 1986, now Patent No. 4,690,229 issued Sept. 1, 1987.
US Referenced Citations (11)
Foreign Referenced Citations (1)
Number |
Date |
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1148957 |
Apr 1985 |
SUX |
Continuations (1)
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820742 |
Jan 1986 |
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Continuation in Parts (1)
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76910 |
Jul 1987 |
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