a is a cut-away view of the earth bit of
b is a bottom view of the earth bit and screen of
a and 3b are perspective views of a screen in unrolled and rolled conditions, respectively.
a and 4b are end views of the screen of
a is a perspective view of a shroud, in accordance with the invention.
b is a partial cut-away view of a region of the earth bit of
In this embodiment, bore 110 is in fluid communication with a bearing passageway 108 and a nozzle passageway 111. Bore 110 is in fluid communication with bearing passageway 108 and nozzle passageway 111 through openings 110a and 110b, respectively. Bearing passageway 108 extends through earth bit body 101 and between bore 110 and journal 104. Nozzle passageway 111 extends through earth bit body 101 and between bore 110 and a nozzle 105. It should be noted that earth bit 100 generally includes one bearing passageway for each lug it includes. Further, earth bit 100 generally includes one nozzle and nozzle passageway for each cutting cone it includes, wherein the nozzle is directed at a corresponding cutting cone.
In operation, lug 102 rotates in response to the rotation of earth bit 100. Cutting cone 103 is engaged with ball and roller bearings 106 and 107 and rotates, in response to contacting earthen annulus, about journal 104. A drilling fluid, such as water and/or air, is often flowed through bore 110. A portion of the drilling fluid is flowed through nozzle passageway 111 and nozzle 105 to spray material, such as earthen annulus, away from cutting cone 103. Earth bit 100 operates more efficiently if material is sprayed away from cutting cone 103 with drilling fluid.
Another portion of the drilling fluid is flowed through bearing passageway 108 and towards cutting cone 103 and journal 104. The portion of the drilling fluid flowed through bearing passageway 108 is used to reduce the temperature of cutting cone 103 and journal 104. In this way, earth bit 100 operates at a lower temperature. However, it is desirable to control the flow of material through bearing passageway 108 and nozzle passageway 111.
In accordance with the invention, screen 112 is positioned in bore 110 to cover openings 110a and 110b, as indicated by a substitution arrow 129 in
When in the rolled condition, screen 112 is biased to move to the unrolled condition. In this way, screen 112 applies a force, denoted as force F, to earth bit body 101 when it extends through bore 110 (
Screen 112 extends between openings 110a and 110b and covers them. In this way, screen 112 extends through bore 110 and between bearing passageway 108 and nozzle passageway 111. Screen 110 includes openings which allow the drilling fluid to flow therethrough. However, the openings of screen 110 are shaped and dimensioned to restrict the flow of undesirable material through openings 110a and 110b. The undesirable material can be of many different types, such as abrasive material like earthen annulus.
a and 3b are perspective views of screen 112 in unrolled and rolled conditions, respectively. It should be noted that screen 112 is in the rolled condition when extending through bore 110. In this embodiment, screen 112 is a rectangular piece of material with openings extending through it. It should be noted that screen 112 can be of many other shapes, but a rectangular shape is shown here for illustrative purposes. Screen 112 has opposed sides 113a and 113b, as well as opposed sides 113c and 113d. Sides 113a and 113b have a width dimension denoted as Wscreen and sides 113c and 113d have a length dimension denoted as Lscreen.
In the unrolled condition, sides 113a, 113b, 113c and 113d extend linearly because screen 112 is a rectangular piece of material. Further, in the unrolled condition, sides 113a and 113b are away from each other, and sides 113c and 113d are away from each other. In the rolled condition, sides 113a and 113b are away from each other and sides 113c and 113d are towards each other. It should be noted that sides 113a and 113b curve in response to moving sides 113c and 113d towards each other. Sides 113c and 113d extend linearly and, when they are proximate to each other, sides 113a and 113b define opposed openings 114a and 114b, respectively, wherein openings 114a and 114b have a diameter dscreen.
a and 4b are end views of screen 112 in the rolled condition. In this embodiment screen 112 is rolled so it has diameter dscreen. Diameter dscreen is variable and depends on the dimensions of screen 112 and the amount of overlap between sides 113c and 113d, as indicated by an indication arrow 116 in
When sides 113c and 113d engage each other, but do not overlap, they form an interface 119, as indicated by an indication arrow 118 in
a is a perspective view of a shroud 121, in accordance with the invention. In this embodiment, shroud 121 includes an open end 122 and a closed end 123, and opposed sides 126 and 127 which extend therebetween. A shroud opening 124 extends through open end 122 and a shroud channel 125 extends between open and closed ends 122 and 123, as well as opposed sides 126 and 127.
b is a partial cut-away view of a region 119, as shown in
Shroud 121 can be carried by screen 112 in many different ways. For example, it can be fastened to screen 112 using a fastener, weld or an adhesive. In other examples, shroud 121 includes hooks which hook to screen 112. Shroud 121 can be removably attached to screen 112 or it can be attached to screen 112 so it is repeatably removeable therefrom.
In operation, drilling fluid flows through bore 110 from closed end 123 towards open end 122 of shroud 121. In this example, the drilling fluid includes water and air. The water flows past shroud 121 and a portion of the air is diverted through opening 124, where it flows upstream through channel 125 to opening 110a. The air flows through screen 112 and into opening 110a and bearing passageway 108 to the earth bit component discussed above. In this way, shroud 121 diverts a material flow between bore 110 and bearing passageway 108 and allows a portion of the drilling fluid to flow upstream so it can enter bearing passageway 108.
The change in direction (i.e. diversion) of the flow of the drilling fluid reduces the amount of water in the air that flows into bearing passageway 108. It is useful to reduce the amount of water that enters into bearing cavity 109 because this increases bearing performance and bit life. The portion of the drilling fluid that does not flow through shroud opening 124 generally flows through nozzle passageway and nozzle 105, as shown in
In a step 202, a screen is provided, wherein the screen is repeatably moveable between rolled and unrolled conditions. In some embodiments, the screen is provided in the rolled condition and, in other embodiments, the screen is provided in the unrolled condition and moved to the rolled condition.
In step 202, the screen is extended through the bore so it covers an opening of the first bearing passageway that faces the bore. In some embodiments, when the screen is in the rolled condition, it is biased to move to the unrolled condition. The screen engages the earth bit body in the bore when it extends therethrough and is biased to move to the unrolled condition. In other embodiments, the screen is held in the rolled condition. The screen can be held in the rolled condition in many different ways, such as with a fastener and weld.
It should be noted that, in some embodiments, a second bearing passageway extends through the lug and is in fluid communication with a nozzle. In these embodiments, the screen covers an opening of the second bearing passageway that faces the bore. The screen extends between the openings of the first and second bearing passageways.
In a step 212, a screen is provided, wherein the screen is repeatably moveable between rolled and unrolled conditions. In some embodiments, the screen is provided in the rolled condition and, in other embodiments, the screen is provided in the unrolled condition and moved to the rolled condition.
In a step 213, a shroud is provided and attached to the screen. In a step 214, the screen is extended through the bore so it covers an opening of the first bearing passageway that faces the bore. The screen is positioned so that the shroud is proximate to the first bearing passageway. In some embodiments, when the screen is in the rolled condition, it is biased to move to the unrolled condition. The screen engages the earth bit body in the bore when it extends therethrough and is biased to move to the unrolled condition. In other embodiments, the screen is held in the rolled condition. The screen can be held in the rolled condition in many different ways, such as with a fastener and weld.
While particular embodiments of the invention have been shown and described, numerous variations and alternate embodiments will occur to those skilled in the art. Accordingly, it is intended that the invention be limited only in terms of the appended claims.
This patent application claims priority to U.S. Provisional Application No. 60/822,913 filed in Aug. 18, 2006, the contents of which are incorporated herein by reference.
Number | Date | Country | |
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60822913 | Aug 2006 | US |