US 3111179 A
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Description (OCR text may contain errors)
ATTORNEY Nov. 19, 1963 G.A.A1.BE1s ETAI.
JETV NozzLEV Filed July 26, 1960 United States Patent O 3,111,179 .EET NOZZLE Gus A. Albers, Houston, and Edward B. Wiilianis, Jr.,
Greenville, Tex., assignors, by mesue assignments, to
A and B Metal Manufacturing Company, lne., Houston,
Tex., a corporation of Texas Filed .luly 26, 196e, Ser. No. 45,373 4 Claims. (Cl. 175-393) lhis invention relates to jet nozzles, `and particularly those for discharging abrasive uids such las the jet nozzles used in rotary drill bits for `drilling earth formations.
For example, rotary drill bits, of this character, are equipped with downwardly and sometimes upwardly directed nozzle-like openings for discharging powerful jets of drilling fluid downwardly between the cutter teeth and onto the 'bottom of the bore hole to remove cuttings rapidly rand to induce upward flow of drilling fluid for carrying the cuttings to the Vtop of the bore hole. Such powerful jets have been very success-ful in cleaning the teeth of the bit and clearing the bot-tom of the hole so that the teeth of the bit are continuously cutting on new formation, thereby greatly increasing the eiciency ot the bit. However, the drilling iluid contains abrasive material, with the result that the surfaces of the nozzle-like openings are soon eroded.
This diiiiculty has been relieved by constructing the jet nozzles of an extremely hard -and dense -metal or metal alloy that is resistant to erosion by the `abrasive action of the high pressure drilling fluid. Because of vthe dii'lculty of machining such hard material, the jet nozzles are usually of cylindrical shape and have an outer diameter to contain a `conical cavity necessary to orrn and direct the jets of drilling tiuid. Also, due to the difficulty in machining the metal, the jet nozzles are simply inserted within the open ended recesses that are provided in the body of the drill bit, and `are retained by a lock-ring fitted into `an annular groove that 'is inset within the open end of the recess. Because it is necessary to make the jet nozzle cylindrical, it is obvious that they contain -a `substantial amount of metal and are expensive. Also, the high pressure fluid acting on the conical surface exents such high pressure on the retaining rings that the jet nozzles are diicul-t to retain in the body of the bit, with the result that the jet nozzles are often pushed out by the pressure into the bottom of the bore hole where they are destructive to the teeth of the bit.
It is therefore the principal object of the present invention to provide a jet nozzle of less expensive construction and which, if it becomes lost, is readily disintegrated by the .teeth `of the bit, without damaging the bit.
Another object of the invention is to provide a jet nozzle with an inner thin walled shell of Wear resistant material yand to provide the exterior `shape by an outer breakable casing of inexpensive nonmetallic material such as a synthetic plastic, whereby the jet nozzle may be produced inexpensively by prcmolding the shell of a tungsten carbide material and molding the plastic about the shell.
Another object ofthe invention is to provide ya jet nozzle with a tungsten carbide shell having sufficiently high density to withstand abrasion and destruction by chemical action ofthe uids.
further obiect of the invention is to provide an improved jet nozzle for replacement of conventional jet nozzles.
In accomplishing these and other objects of the invention as hereinafter pointed out, we have provided improved structure, the preferred form yof which is illustrated in the accompanying drawings, wherein:
FIG. l is a sectional view through the bottom of a bore 3jr-,l l l,179 Patented Nov. 19, 1963 race hole being drilled by `a rotary bit equipped with jet nozzles embodying the features of the present invention.
FIG. 2 is a 'fragmentary section ,through a portion of the body of the bit and the improved jet nozzle contained therein, ythe section being taken on the line 2 2 of FiG. l.
FG. 3 is ya similar section, but showing the parts in disassembled -and in spaced apart relation to .better illustrate the construction.
FIG. 4 is a perspective view of the shell as viewed from the outlet end thereof.
FIG. 5 is `a similar view as viewed from the inlet end thereof.
Referring more in detail to the drawings:
1 designates :a bore hole being `drilled through an earth formation 2 by la drill bit 3 attached to the lower end of a drill pipe 4. The ydrill pipe extends to the top of the bore hole and is rotated in accordance with the usual practice. The drill bit 3 includes a body 5 that is attached to ythe lower end of the drill pipe and carries cutters 6 having cutting teeth 7 that roll upon and chip away the bottom of the bore hole. Circulated under high pressure from the top ot the bore hole is a drilling huid that `discharges through the body of the bit in yone or more downwardly directed jets 8 that discharge between the teeth of the cutters and onto the bottom of Ithe bore hole to clean the teeth 7 `and to clear the bottom of the bore hole of cuttings. The `cuttings yare washed upwardly of the bore hole on :the exterior side of the drill pipe to the upper end thereof, in `accordance with rotary drilling of bore holes. The bit body may also be provided with one or more upwardly directed jets 9 to increase the velocity of the upward iiow of the drilling uid.
As above described, `such `drilling fluid contains abrasives 'and is destructive to the jet oriiices lo and ll that are provided in the body of the bit. This dihiculty has been relieved by providing the body of the bit with recesses 12 for containing jet nozzles or inserts in the shape of a cylinder. The cylindrical jet nozzles are completely formed oi extremely hard, highly resistant metal or metal alloy having conical cavities shaped to provide the jet orifices.
As above described, such cylindrical jet nozzles are dilicult to manufacture and machine, consequently the machining to retain them is carried out on the body of the bit. The portions 13 of the body of the bit that contain the iiuid passageways 'i4 are counterbored to provide the recesses l2 and form shoulders l5 against which the inlet ends of the jet nozzles abut, and are retained by an expansion ring 16 which is inserted in an annular groove 17 that is inset from the open end 1S ot" the recess l2 as shown in FIG. 2. In order to prevent leak` age of the drilling uid around the exterior of the cylindrical jet nozzle, the recess 12 is encircled by an annular groove 19 containing a sealing element such as an O ring 2li.
'In order to provide less expensive and more satisfactory jet nozzles, the present invention contemplates a jet nozzle that replaces the present extremely expensive nozzles and which may be retained in a like manner. The jet nozzles of the present invention are of composite construction in that they include a thin walled inner shell 21 of the expensive wear resistant material and an outer casing 22 of less expensive `and breakable material that is preferably molded about the circumference of the shell in order to make iirm Contact therewith and assure complete backing and support of the shell.
The wear or abrasion resistant shell 2-1 may be constructed by casting or by sintering, but preferably by molding thereof under heat and pressure. The materials used are preferably granules of tungsten carbide or a like alloy and a suitable bonding metal such a cobalt, nickel 3 or the like, combined under heat and pressure in a Imold having a cavity corresponding to the inner and outer contour of the shell. In order to reduce porosity, the grain sizes of the tungsten carbide are regulated to eliminate as much as possible voids between particles.
The shell 211 has a cylindrical neck portion 23, forming the discharge orifice of the nozzle, and a generally conical body portion 24 aring from the neck portion 23, whereby the base 25 thereof forms the inlet 26 t0 the nozzle. The wall thickness of the neck and body portions need be only enough to withstand application of the casing 22. The shell is, therefore, of minimum weight and contains a minimum amount of the costly material.
In forming the casing, the shell rnay be placed coaxially within a cylindrical cavity of a mold (not shown) and the plastic material is extruded into the mold to now around the shell with suicient pressure to assure a rm contact with the surface of the shell and to form a smooth exterior cylindrical surface 2,7 conforming to the cylindrical surface 28 of the recess 12. After the molding operation, there is sufficient cohesion between the pfl-astic material and the exterior surface `of the shell to maintain the parts in unitary assembly and assure a solid and firm backing of the thin walled shell. While we have particularly specified a plastic material, other materials may be substituted that are capable of fiowing around the shell and which are capable of taking on a set without placing the shell under undue stress. It is also essen tial that a casing material be selected which will maintain tightness of the shell therein under different temperature conditions to which the jet nozzles may be subjected.
In inserting a jet nozzle constructed as described, the ring is inserted in the groove 19 and the jet nozzle is inserted in the recess until the base is in abutment with the shoulder 15. After insertion of the jet nozzle, the expansion ring 16 is contracted to a diameter for movement through the open end of the recess 12 until it comes in contact with the end face of the nozzle, whereupon it is lallowed to spring into the annular groove 17 to clock the jet nozzle in position.
With the jet nozzle in place, the drilling uid contacts only the interior surface of the shell 21. The shell 21 thus resists abrasion by the abrasive elements in the drilling fluid, so that the jets may be discharged with sufficient velocity to accomplish the intended purpose. It is obvious that the casing is completely shielded from the erosive effects of the drilling liuid by the shell, and `at the same time the casing provides firm and solid backing for the shell.
Should one or more of the jet nozzles become displaced and lost into the bottom of the hole, the casing being relatively soft and the shell relatively frangible are readily broken up by the bit without damaging the teeth 'of the cutters. Any fragments of the jet nozzle are immediately reduced as -to size vvhere they are easily washed to the top of the hole along with the cuttings.
From the foregoing, it is `obvious that we have provided a jet nozzle capable of `withstanding the abrasion of high pressure jets with a minimum amount of the costly tungsten carbide material. The jet nozzles may therefore 'be supplied at a comparatively low cost. It is also obvious that the casing portion thereof adequately backs and supports the Ishell portion. If one or more of the jet nozzles are displaced, it is obvious that Ithe composite unit is readily disrupted and disposed of without damaging the teeth of the cutters.
What We claim `and desire to secure by Letters Patent is:
1. A jet nozzle comprising -a thin Walled shell of Wear resistant material and having ran inner surface of a shape to provide a discharge orice and a generally conical inlet converging into said discharge orifice and having an exterior surface conforming in shape to said inner surface for providing a thin wear resistant wall of substantially uniform thickness, and a plastic casing providing a solid and rm backing surrounding the periphery of the shell and having an inner surface in cohesive contact with the `entire outer surface of the shell and having a generally cylindrical outer periphery.
2. A jet nozzle for drilll bi-ts and the like, said jet nozzle comprising a thin walled shell of wear resistant material composed of an alloy principally of tungsten carbide granules and a bonding metal and havin-g an inner surface of a shape =to provide an annular discharge orifice and a generally conical inlet converging into said annular discharge orifice and having an exterior surface conforming in shape to the inner surface to provide a thin Wear resistant Wall of substantially uniform thickness, and a plastic casing providing a solid and firm backing surrounding the periphery of the shell and having an inner surface in cohesive contact with the entire outer surface to firmly support said shell when the jet nozzle is mounted within a drill bit and having a generally cylindrical outer periphery, said plastic casing having the property of disintegrating with the shell in case the nozzle should become dislodged from the drill blt.
3. A jet nozzle comprising 4a thin iwalled shell of wear resistant material composed of an :alloy principally of tungsten carbide granules combined with a bonding metal and having an inner surface of la shape to provide a discharge orifice and a generally conical inlet converging into said discharge orifice and having an exterior surface conforming in shape to the inner surface to provide la thin wear resistant wall of substantially uniform thickness, and a breakable nonmetallic casing providing a iirm backing surrounding the periphery of the shell and having an inner -surface in cohesive contact with the entire outer surface `of the shell and having Ia generally cylindrical outer periphery, said inner shell being frangible upon breaking apart of the casing.
4. In a drill bit having a Channel for passing 'drilling fluid to the cutting elements of the drill bit and having a cylindrical counter-recess -at the discharge end thereof and forming an annular shoulder encircling the channel, a jet nozzle in said recess comprising a thin walled shell of wear resistant material composed of an alloy principally of tungsten carbide granules combined with a bonding metal and having yan inner surface `of a shape to provide a discharge orifice and a generally conical Iinlet end abutting said shoulder converging therefrom into said discharge orifice and having an exterior surface conforming in shape to the inner surface to provide a ,thin wear resistant wall yof substantially uniform thickness, and a breakable plastic casing providing a firm and solid backing surrounding the periphery of the lshell and having an inner surface in cohesive contact with the entire outer surface -o-f the shell and having a generally cylindrical outer periphery hitting the counterbore and protected by the shell from ythe erosive effects of the drilling uid, said inner :shell being frangible upon breaking apart of the plastic casing by said cutting elements of the bit upon accidental Idisplacement of the jet nozzle from said recess when lthe bit is in use.
References Cited in the le of this patent UNITED STATES PATENTS