US5348770A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of forming an uninterrupted refractory coating on a downhole drill bit cone
Assignee: Tmt Research Development Inc
•
Filing: 1992-05-04
•
Granted: 1994-09-20
•
Expires: 2012-05-04
Abstract
Abstract Drill bits having projecting inserts are completely coated with refractory material including on the edge margins about the inserts by thermally spraying with refractory particles whose particulate constituent under the spraying conditions is able to penetrate the inserts. Completely coated drill bits are provided.
Inventors
- 👤 G. Kelly Sievers
- 👤 Rajan K. Bamola
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 22:40
CPC Classifications
E; E21; E21B; E21B10/00; E21B10/46; E21B10/50; E21B10/52
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
106 words
Method of coating a drill bit having refractory inserts projecting therefrom out of supporting pockets having edge margins surrounding said inserts, including thermally spraying refractory particles comprising binder and refractory particulate against the bit and inserts under conditions such that said refractory particles penetrate said inserts and do not bounce back from said inserts so as to leave said edge margins about said inserts uncoated, whereby said thermally sprayed refractory particle coating on said inserts and on said bit join in a bridge coating on said pocket edge margins to form a continuous, uninterrupted coating over said bit and said inserts which protects said edge margins.
Claim 2
Dependent Claim
106 words
Method of coating a drill bit having refractory inserts projecting therefrom out of supporting pockets having edge margins surrounding said inserts, including thermally spraying refractory particles comprising binder and refractory particulate against the bit and inserts under conditions such that said refractory particles penetrate said inserts and do not bounce back from said inserts so as to leave said edge margins about said inserts uncoated, whereby said thermally sprayed refractory particle coating on said inserts and on said bit join in a bridge coating on said pocket edge margins to form a continuous, uninterrupted coating over said bit and said inserts which protects said edge margins.
Claim 3
Dependent Claim
23 words
The method according to claim 1, including spraying said particles at a temperature sufficient to soften said binder for flattening against said bit.
Claim 4
Dependent Claim
14 words
The method according to claim 1, including selecting tungsten carbide as said refractory particulate.
Claim 5
Dependent Claim
22 words
The method according to claim 1, including selecting cobalt at from 9 to 12% by weight of said particles as said binder.
Claim 6
Dependent Claim
14 words
The method according to claim 1, including selecting tungsten carbide inserts as said inserts.
Claim 7
Dependent Claim
18 words
The method according to claim 1, including directing said spraying substantially normal to the surfaces of said bit.
Claim 8
Dependent Claim
20 words
Method according to claim 1, including spraying said refractory particles at feed rates from 1 to 12 pounds per hour.
Claim 9
Dependent Claim
20 words
Method according to claim 1, including selecting particulate wherein said particles are from 10 to 33 microns in particle size.
Claim 10
Dependent Claim
53 words
Method according to claim 1, including effecting a first combustion of fuel in a first chamber to thermally spray said refractory particles and effecting a secondary combustion of fuel in a physically separated second chamber beyond said first combustion chamber to further effect thermal spray of said refractory particles in twice heated condition.
Claim 11
Dependent Claim
14 words
The method according to claim 2, including selecting tungsten carbide as said refractory particulate.
Claim 12
Dependent Claim
22 words
The method according to claim 10, including selecting cobalt at from 9 to 12% by weight of said particle as said binder.
Claim 13
Dependent Claim
14 words
The method according to claim 11, including selecting tungsten carbide inserts as said inserts.
Claim 14
Dependent Claim
18 words
The method according to claim 12, including directing said spraying substantially normal to the surfaces of said bit.
Claim 15
Dependent Claim
22 words
Method according to claim 13, including spraying said tungsten carbide refractory particles at feed rates from 1 to 12 pounds per hour.
Claim 16
Dependent Claim
22 words
Method according to claim 14, including selecting tungsten carbide particulate wherein said particles are from 10 to 33 microns in particle size.
Claim 17
Dependent Claim
50 words
Method according to claim 15, including thermally spraying said refractory particulate with a first combustion of fuel in a first chamber and a secondary combustion of fuel in a second chamber physically separate from and beyond the first combustion chamber, whereby said refractory particulate is sprayed in twice heated condition.
References Cited (Backward Citations)
US4372404A
Cited
US4396077A
Cited
US4593776A
Cited
US4592252A
Cited
US4597456A
Cited
US5019686A
Cited
US5206059A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-09-19 | 1998-03-21 | 1998-09-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-09-19 | 2002-03-21 | 2002-09-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-09-19 | 2006-03-21 | 2006-09-20 | $7700.00 | Window Closed / Lapsed |