Dual-function pressure compensator for sealing the oil storage cavity of mining drill bits

Abstract

The present invention provides a mining drill bit with a sealed bearing, the mining drill bit having a dual-function pressure compensator for an oil storage chamber. The mining drill bit has a drill bit body and a downwardly extending tooth palm, the tooth palm including a journal extending inwardly and downwardly for mounting a rotating cone, and a seal disposed between the journal and the cone. A grease flow path extends from the inner cavity of the drill bit body, through the tooth palm and the journal, and to an intermediate space between the journal and the cone. A pressure compensator extends between the inner cavity and the flow path and has a movable piston. When the piston is locked in place, the compensator can operate in a grease system mode, or in an air flow bypass mode by removing a locking member from the position in which the piston is fixed before the mining drill bit is secured to the drill string.

Description

Technical Field

[0001] The present invention relates to a mining drill bit, and more particularly to an air flow bypass for use with a grease compensator in a sealed bearing drill bit. Background Art

[0002] Bottom penetration tools include rotatable knife-type mining drill bits, such as roller cone drill bits. Roller cone mining drill bits have a drill body having an upper end adapted to be connected to a drill string and typically having three drill legs extending downwardly from the body. Descending from the lower portion of the drill body are a plurality of support arms, typically three in number. A journal extends inwardly and downwardly from each of the drill legs. Conventional drill bit support shafts are cylindrical and rotatably receive a roller cone. A journal cone is typically mounted on each journal and rotatably supports each roller cone on a bearing between the main shaft and the interior of the main shaft receiving cavity. As the roller cone rotates on the journal, the roller cone has teeth or pressure blocks on its outer surface for breaking up the formation. One or more fluid nozzles are typically disposed on the underside of the drill body. The nozzles are typically configured to direct drilling fluid downwardly from the drill string toward the bottom of the borehole being drilled. The drilling fluid flushes material removed from the bottom of the borehole and cleans the cones, carrying drill cuttings and other debris radially outward and then upward within the annulus defined between the drill bit and the borehole wall.

[0003] Several support systems are used to support the cone. These support systems typically consist of a combination of radial and thrust bearings, which can be sealed and lubricated, or unsealed and open to the drilling fluid. The drilling fluid can be a liquid, such as mud, or a gas, such as air. The contact wear surfaces for the journals can be composed of wear-resistant metals or non-metallic materials, such as tungsten carbide. In sealed bearing drill bits, seals are placed in the gap between the cutting cone and the corresponding journal to prevent debris from contaminating the bearing and also to prevent grease from leaking to the outside. Various types of seals have been used, including elastomeric seals and metal-to-metal face seals. Open bearing drill bits operate without seals and typically pass drilling fluid through the cone bearings for cooling and lubrication. Open bearings typically pass drilling fluid through ports through the bearing system to lubricate and cool the bearing wear surfaces. In some cases, air can be used as the drilling fluid and forced through the bearings to cool and lubricate the bearings.

[0004] When operating in a fluid-filled borehole, static pressure acts on the drill bit due to the weight of the drilling fluid column. As the drill bit is lowered into the hole, the temperature of the grease increases due to heat transfer, and the frictional heat from rotation causes the grease to expand. A sealed, grease-lubricated bearing drill bit contains a lubricant reservoir in the drill body that supplies oil to the journals. Each journal has a pressure compensation system mounted in the reservoir in the drill body. Sealed bearing drill bits typically use a lubrication system that includes a grease pressure compensator to limit the pressure difference between the grease and the pressure in the borehole. A typical grease compensator consists of a flexible diaphragm or spring-biased piston that separates the reservoir and grease from the borehole fluid. The diaphragm or spring-biased piston moves due to the pressure differential across it, tending to equalize the pressure difference between the reservoir pressure and the borehole fluid pressure. A lubricant flow channel extends from the compensator's reservoir to the exterior of the journal. The pressure compensation system has a communication port that communicates with the static pressure on the outside to equalize the pressure on the outside with the grease pressure in the channels and gaps within the drill bit. As the cone rotates on the journal, the viscous grease generates hydrodynamic lift, so that the load is supported partially by the grease fluid film and partially by surface-to-surface contact.

[0005] Sealed bearing drill bit failures are usually caused by the cone bearing seals wearing out until they fail, which causes the bearing to fail before the cutting structure wears out. Therefore, it is desirable to extend the life of sealed bearing drill bits beyond the life of the seals. Summary of the Invention

[0006] The present invention discloses a mining drill bit having a dual-function pressure compensator for an oil storage chamber. The mining drill bit is preferably a sealed roller drill bit having a roller that provides cutting. The grease pressure compensator can operate in a sealed lubrication system mode or in an airflow bypass mode selected before the mining drill bit is secured to the drill string. The mining drill bit has a drill body and a downwardly extending tooth palm, the tooth palm including an inwardly and downwardly extending journal or shaft for mounting a rotating roller, and a seal disposed between the journal and the tooth palm. A grease flow path extends from the inner cavity of the drill body, through the journal and the journal, and to an intermediate space between the journal and the roller. A grease compensator extends from the flow path into a cavity having a bore end, with a compensator piston located within the bore end. The grease compensator has an elongated tube having an inwardly facing end disposed within the flow path and a component for receiving the piston when grease is discharged from the elongated tube. A through hole passes through the side wall of the elongated tube, is separated from the end by the cavity, and is in fluid communication with the flow channel.

[0007] The grease compensator can operate in a sealed grease system mode using a retainer member that selectively locks the piston in a fixed position within the elongated tube, without providing pressure compensation. Alternatively, the grease compensator can operate in a flow bypass mode in the event of a bearing failure by removing the retainer member that secures the piston in place within the elongated tube before securing the mining drill bit to the drill string. With the retainer member removed, the piston is free to move along the length of the elongated tube and provide pressure compensation for the grease flow channel. As the seal between the cone and the journal wears, lubricant will drain from the flow channel, and the piston will move to the lower end of the elongated tube, allowing drilling fluid to flow through a hole in the lower end of the elongated tube, around the piston, and through the grease flow channel. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] For a more complete understanding of the present invention and its advantages, reference is now made to the following description taken in conjunction with the accompanying drawings, in which Figures 1 to 6 Various aspects of a dual-function pressure compensator for sealing a mining drill bit made in accordance with the present invention are shown as follows:

[0009] Figure 1 is a perspective view of a sealed mining drill bit having a dual-function compensator for an oil reservoir, with the drill bit body shown in longitudinal quarter section;

[0010] Figure 2 It is along Figure 1 A cross-sectional view of one of the palms of the drill bit taken along section line 2-2, showing the dual-function reservoir with the piston in the initial upper position;

[0011] Figure 3 It is along Figure 1 A cross-section of one of the drill bit's teeth, taken along section line 2-2, shows the dual-function reservoir after the piston has moved to its lower position;

[0012] Figure 4 This is an exploded view of the dual-function compensator of the oil storage chamber;

[0013] Figure 5 yes Figure 2 and Figure 3 A cross-sectional view of a journal, along Figure 3 and Figure 4 A cross section rotated about the central longitudinal axis 28; and

[0014] Figure 6 It is along Figure 5 End view of the journal taken through section 6-6. DETAILED DESCRIPTION

[0015] Figure 1FIG. 1 is a perspective view of a drill bit 12, with the drill body 14 shown in a quarter longitudinal section. The drill body 14 has at least one tooth leg 16, three of which are shown. A rotating cone 20 is rotatably mounted on the legs 16 by a journal 18 ( Figure 3 ). The rotating cone 20 is shown having inserted cutting teeth 22, preferably tungsten carbide inserts ("TCI"), although other types of cutting teeth, such as steel teeth and abrasive surfaces, may also be used. The cutting teeth 22 are preferably tungsten carbide inserts or steel teeth. A nozzle hole 24 is provided at the lower end of the drill bit body 14 for receiving drilling fluid flowing from the interior cavity 30 of the drill bit body 14 and spraying it through the nozzle 24 onto the rotating cone 20 of the drill bit body 14. The drill bit body 14 has a drill bit connection end 26 for connection to a drill string.

[0016] The drill bit body 14 has a central longitudinal axis 28. An internal cavity 30, or drill bowl, extends into the drill bit body 14 and is connected to the bore of the drill string for receiving drilling fluid through the drill bit body 14 for cooling the drill bit 12, cleaning cuttings from the rotating cone 20, and circulating the cuttings upward through the drill hole. Grease pressure compensators 32 (two shown) are mounted in the drill bit body 14, one in each of the teeth 16. The compensators 32 extend from the internal cavity 30 into respective compensator ports 34. In each tooth 16, an oil reservoir 33 is defined by the combination of the compensator port 34, grease flow passage 36, grease port 38, grease port 104, and a ball port 80, which is fluidically connected without a ball valve 82. An annular space 40 is defined by the exterior of the compensator 32 by a gap extending between the walls of the compensator port 34. The compensator port 34, the oil reservoir 36, the grease port 104, the grease port 38 and the ball port 80 are bored into the body of the tooth palm 16 by interconnected holes. The oil reservoir 36 extends into the tooth palm 26 by a drill hole, preferably parallel to the axis 28. The oil reservoir 36 has a large capacity for accommodating the oil reservoir 33. The outer end of the oil reservoir 36 is sealed with a plug 68. A filler port 65 and a drain port 67 connect the oil reservoir 36 to the outside of the tooth palm 26 and between the drill bit 12. Gas enters the oil reservoir 33 through the flow channel 36 of the filler port 65 and is discharged through the drain port 67. The filler port 65 vent port 67 can be sealed with a weld after the oil reservoir is filled with grease. The plug 68 can be used to seal the end of the grease 36.

[0017] Figure 3 and 4 is a partial cross-sectional view of the drill bit 12, Figure 3 The drill bit 12 is shown configured for operation in a sealed bearing mode. Figure 4The drill bit 12 is shown configured to operate in an open bearing mode. The compensator port 34 extends from the internal cavity 30 to the grease reservoir 36. The grease reservoir 36 is a bore extending from the hole providing the compensator port 34 to the ball port 80. A grease port 38 is defined by a pilot hole extending from the ball port 80 to the end of the journal 18 located at the thrust bearing 86. The compensator port 34 and the compensator 32 are sized to form an annular space 40 therebetween. The annular space 40 provides a flow path for fluid to flow from the compensator 32 into the compensator port 34.

[0018] The compensator 32 preferably has a cylindrical tubular body defined by a tube 42. The compensator tube 42 has a lower end 50 preferably defined by an upper end 48 and an opposite end. The upper end 48 is disposed within the lumen 30 and preferably defines a bore diameter by the throughbore 44 extending outwardly around the tube 42 adjacent the upper end 48. The throughbore 44 is in fluid communication with the lumen 30 and provides fluid communication between the lumen 30 and the interior of the tube at the end of the tube 42 defined by the upper end 48. The lower end 50 is configured to extend into the compensator port 34 and has a bore 46 preferably defined by a throughbore extending outwardly around the tube 42, spaced from the lower end 50 by a member 52. The member 52 preferably has a tubular interior profile sized to have a diameter and longitudinal length for receiving a piston 54 disposed adjacent the bore 46 such that fluid flow from the lower end 42 and the throughbore 44 to the bore 46 is unimpeded by the piston 54, as shown. Figure 3 shown.

[0019] The piston 54 is slidably disposed within the tube 42 and has a piston seal 56, preferably an O-ring. A groove 116 extends circumferentially around the piston 54 and, in conjunction with the inner surface of the tube 42, forms a sealing gland for receiving the piston seal 56. A first retainer member 58 preferably comprises a first cotter pin extending through a retainer port 118 on the rod 114 at the upper end of the piston 54 and a hole near the upper end 48 of the tube 42, securing the piston 54 in position within the tube 42 unless the retainer member 58 is removed before the drill bit 12 is operated in the well, as described below. A second retainer member 60 preferably comprises a second cotter pin extending through an opposing hole in the lower end 48 of the tube 42, adjacent to one end of the piston 54 near the inner cavity 30. A flange 62 preferably extends circumferentially around the middle portion of the tube 42, between the upper end 48 and the lower end 50. Through-hole 44 is preferably provided between upper end 48 and flange 62, providing fluid communication between compensator port 34 and the interior of tube 42. Aperture 46 is preferably provided between lower end 50 and flange 62, providing fluid communication between compensator port 34 and the interior of tube 42. Flange 62 is preferably welded to the opening of compensator port 34, securing compensator tube 42 to bit body 14. A recess 66 may be provided, countersunk from the outward opening of compensator port 34, to accommodate flange 62. Flange 62 preferably extends continuously around the periphery of compensator tube 42, but in some embodiments, may be a tab projecting radially outward from the outer surface of compensator tube 42. When flange 62 does not extend continuously around the circumference of compensator tube 42, seal 64 may be an O-ring for sealing compensator port 34 against the exterior of tube 42. Seal 64 may be omitted when welding between flange 62 and the opening of compensator port 34 provides a fluid-tight seal.

[0020] The journal 18 has a main shaft or pin on which the rotating cone 20 is rotatably mounted. The journal 18 preferably has a main portion 70 and a guide portion 72. An outer bearing 74, preferably a roller bearing, is disposed on the main portion 72. An inner bearing 76, preferably a roller bearing, is disposed on the guide portion 72 of the journal 18. A ball bearing 78 conventionally locks the rotating cone 20 to the journal 18. A ball plug 82 is welded to the ball port 78 to secure the ball bearing 78 between the bearing race of the journal 18 and the rotating cone 20. The ball plug 82 has a tapered portion 84 within the ball port 80 to facilitate fluid flow from the oil reservoir 36 to the grease port 38. A thrust bearing 86 is located at the outer end of the journal 18. An intermediate space 88 is located between the journal 18 and the rotating cone 20, forming a gap between the journal 18 and the rotating cone 20. Outer bearing 74, inner bearing 76, ball bearing 78, and thrust bearing 86 are located in intermediate space 88. Seal 90 seals intermediate space 88 between journal 18 and rotating cone 20. Seal 90 is an elastomeric portion, such as an O-ring, a metal-to-metal seal, or another type of seal, such as an oval or flat seal, and is preferably formed from an elastomer.

[0021] Figure 4FIG. 8 is an exploded view of a grease pressure compensator 32 having a longitudinal axis 92. The compensator 32 includes a compensator tube 42, a piston 54 with a piston seal 56, a retainer member 58, and a retainer member 60. The piston 54 and the piston seal 56 are slidably disposed within the compensator tube 42. A throughbore 44 is located at an upper end 48 of the compensator tube 42, and the bore 46 is separated from the lower end 50 by a member 52. A flange 62 projects between the upper end 48 and the throughbore 44 and the lower end 50 and the bore 46. The piston 54 includes a body portion 112 that is a selectively removable plug for sealing the interior of the compensator tube 42. A sealing groove 116 extends circumferentially into the body portion 112 of the piston 54 for accommodating the piston seal 56, which is preferably an annular elastomeric seal. The piston 54 also has a stem 114 extending upward from the body portion 112 and a retainer port 118 for receiving and passing a retainer member 58 through the retainer port 118. The retainer member 58 preferably extends through a pair of opposing through-holes 44 in the sidewall of the compensator tube 42 near the upper end 48. A retainer member 60 also preferably retains the piston 54 within the compensator tube 42 through the two opposing through-holes 44 in the sidewall of the compensator tube 42, preventing the piston 54 from moving out of the compensator tube 42 and into the interior cavity 30 of the drill bit body 14. A hole 46 extends through the sidewall of the member 52 near the lower end 50 of the compensator tube 42. The member 52 receives the piston 54 after the compensator tube 42 is drained of lubricant, and the hole 46 allows drilling fluid to bypass the piston 42 and flow out of the compensator tube 42 and the compensator port 34, and into the oil reservoir 36 through the grease port 38. The seal 64 seals between the countersunk grooves 66 between the flanges 62 to form the toothed leg 16 .

[0022] Figure 5 is Figure 2 and 3 2 is a cross-sectional view of the journal 18 rotated about its longitudinal axis 28. A lubricant port 104 extends from the lubricant port 38 through the main portion 70 of the journal at a flat surface 108 to the space 88 adjacent the inner bearing 76 for passage of fluid. A second lubricant port 106 extends from the lubricant port 38 to the second flat surface 108. The hardened face 102 is disposed in a groove 100 that extends to the annular end surface of the main portion 70 of the journal 18.

[0023] Figure 6 yes Figure 5An end view of the journal 18 is shown in section 6-6. A hardface 102 is provided on the annular end face of the main body portion 70 of the journal 18, adjacent the base of the pilot bearing 72 of the journal 18. Two flat surfaces 108 are provided on opposite sides of the pilot bearing 72. Grease ports 104 and 106 terminate at flat plate 108. Flat surfaces 108 are located in the annular end of the outer bearing, on opposite sides of the pilot portion 72 of the journal 18. Flat plates 108 provide clearance to provide an intermediate space 88 for the passage of grease and, later, well fluid, between the rotating cone 20 and the journal 18.

[0024] The compensator 32 for the drill bit 12 is configured such that the piston 54 is locked in place by the locking member 58 when in the sealed grease system mode, or in the airflow bypass mode, before the drill bit 12 is secured to the drill string, by removing the locking member 58 to prevent the piston 54 from being secured. When operating in the sealed grease system mode or the sealed bearing mode, the piston 54 remains in place and grease is gravity fed from the reservoir 36, the grease port 38, and the compensator 32 into the bearing clearance between the journal 18 and the selector cone 20. In this mode, the compensator 32 does not provide compensation for pressure differences between the reservoir 36 and the grease port 38, and between the grease port 38 and the exterior of the drill bit 12, because the piston 54 is fixed in place within the compensator tube 42.

[0025] When the compensator 32 operates in the bypass mode, the locking member 58 is removed from the fixed piston 54 in its fixed position within the compensator tuner 43. The piston 54 is free to move according to the pressure differential between the oil reservoir 36 and the grease port 38. Initially, the compensator 32 operates in the sealed bearing mode, with the piston 54 fixed within the tube 42 adjacent to the upper locking member 60. As the drill bit bearing seal wears and grease migrates from the drill bit 12, the piston 54 is free to move within the compensator tube 42 in response to the pressure differential between the grease port 38 and the oil reservoir 36. As well depth and drill bit 12 temperature increase and decrease, the pressure within the grease port 38 increases and decreases, respectively. These pressure fluctuations act on the end of the piston 54 near the inner chamber 30 and the compensator tuner's position within the tube 42. Grease fills the compensator port 34, the oil reservoir 36, the grease port 38, and the compensator tube 42, which collectively form a reservoir. The piston 54 and piston seal 56 together provide a movable sealing assembly in a first position. The piston 54 and piston seal 56 preferably work together to compensate for the pressure difference between the lubricant reservoir and the drilling pressure near the drill bit 12 using drilling fluid pressure from the lubricant port 38. After drilling, when seal 90 wears out and fails, lubricant is expelled from the compensator tube 42 and forced out of the intermediate space 88 and seal 90. The pressure in the internal cavity 30 pushes the piston 54 from the first position near the upper end 48 to the second position, located in the component 52 near the lower end 50 and adjacent to the bore 46. The drill bit 12 then operates in an open bearing mode. This allows drilling fluid to flow in a bypass flow path extending from the internal cavity 30 through the compensator 32 and bore 46 to the compensator port 34. The drilling fluid will flow through the oil reservoir 36 and grease port 38, then through the intermediate space 88 and the area where the seal 90 is located at the drill hole. The compensator 32 thus has a bypass flow passage for the passage of drilling fluid through the oil reservoir 36, the grease port 38 and the intermediate space 88 allowing the sealed bearing drill bit 12 to operate in an open bearing mode following a main cone bearing seal failure.

[0026] The drilling fluid is preferably air, although other water-based or oil-based drilling fluids may also be used. It should be noted that the cross-sectional areas of compensator port 34, oil reservoir 36, grease port 38, and compensator tube 42 are sized to pass a sufficient amount of drilling fluid to provide adequate cooling and lubrication of drill bit 12. The cross-sectional area of ​​the bore is preferably sized to provide an annular space 40 with sufficient dimensions to pass an appropriate amount of drilling fluid. Similarly, upper end 48, in conjunction with through-hole 44 and bore 46, is sized to allow the drilling fluid to flow through without excessive pressure loss.

[0027] The present invention provides the advantage of a mining drill bit that can initially operate in a sealed bearing mode. Once the seal fails, the drill bit operates in an open bearing mode using a drilling fluid for cooling the drill bit. Air is preferably used as the drilling fluid, but water-based and oil-based drilling fluids can also be used.

[0028] Although the preferred embodiment has been described in detail, it should be understood that various changes, substitutions and alterations can be made hereto without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

1. A mining drill bit, characterized in that: include: a drill bit body, with at least one journal mounted on the drill bit body; A rotating cone is mounted on the journal for rotation, and an intermediate space is defined between the rotating cone and the journal; The seal is provided between the journal and the rotating cone to seal the intermediate space outside the drill bit; An oil storage cavity is defined by a combination of the compensator port, the grease flow channel, the grease port, and the ball port; a fill port and a drain port connect the oil storage cavity to the outside of the tooth palm and between the drill bit; a flow channel extending through the drill bit body from the inner cavity of the drill bit body to an intermediate space between the journal and the rotating cone; a dual-function compensator extending between the flow passage and the inner cavity of the drill bit body, the dual-function compensator including a compensator body having a first end in fluid communication with the inner cavity of the drill bit body and a second end in fluid communication with the flow passage; The dual-function compensator has a movable sealing member disposed in the compensator body for at least initially being disposed in a first position adjacent the first end of the compensator body and preventing fluid flow through the compensator body and movable to a second position enabling fluid flow through the compensator body; The dual-function compensator further includes: a retainer member for securing the movable sealing member in the first position, wherein the retainer member is further configured to release the movable sealing member from being secured in the first position so that the movable sealing member can move according to a fluid pressure difference between the inner cavity of the bit body and the flow passage, and wherein, after fluid is discharged from the compensator body, the movable sealing member is disposed in the second position within the compensator body, the movable sealing member being located on one side of a flow passage for transferring fluid flow from the inner cavity of the bit body to the flow passage; The drill bit body also includes a flow passage through the drill bit body having a terminal end adjacent to the inner cavity of the drill bit body, the terminal end defining a compensator port, wherein the compensator port is larger than the cross-sectional dimensions of the remainder of the flow passage, and the compensator tube has a lower end extending into the compensator port; and wherein the compensator port is sized to interface with the dual-function compensator, a gap is provided between the dual-function compensator and the compensator port, and the gap is sized to allow fluid to flow from the inner cavity of the drill bit body to the flow passage; further comprising a through hole provided on a side wall of the compensator body for allowing drilling fluid to enter the compensator body from the inner cavity of the drill bit body through the through hole, and a hole through the side wall of the compensator body for allowing drilling fluid to enter the flow channel from the compensator body, wherein the through hole, the hole, the flow channel and the intermediate space between the journal and the rotating cone are sized to allow drilling fluid to pass therethrough; the movable sealing member having a body and an upwardly extending stem about which a seal is mounted, the upwardly extending stem having a retaining port for receiving the retainer member; and wherein the retainer member includes a removable pin extending through two opposing through-holes in the through-hole and through the retaining port for securing the movable sealing member in the first position; The dual-function compensator has a flange extending outwardly from a middle portion of the dual-function compensator, and the flange engages the compensator port disposed at a terminal end of the flow passage and positions the dual-function compensator at the compensator port.

2. The mining drill bit according to claim 1, characterized in that: The flange is welded to the drill bit body to secure the first end of the dual-function compensator to the compensator port.

3. The mining drill bit according to claim 1, characterized in that: An elastomeric seal is provided between the dual-function compensator and the compensator port for sealing engagement therebetween.

4. A mining drill bit, characterized in that: include: A drill bit body; at least one journal is mounted on the drill bit body; A rotating cone is mounted on the journal for rotation, and an intermediate space is defined between the rotating cone and the journal; The seal is provided between the journal and the rotating cone to seal the intermediate space outside the drill bit; An oil storage cavity is defined by a combination of the compensator port, the grease flow channel, the grease port, and the ball port; a fill port and a drain port connect the oil storage cavity to the outside of the tooth palm and between the drill bit; The flow passage extends from the inner cavity of the drill body to the intermediate space between the journal and the rotating cone; a dual-function compensator extending between the flow passage and the inner cavity of the drill bit body, the dual-function compensator comprising an elongated body having a first end in fluid communication with the inner cavity of the drill bit body and a second end in fluid communication with the flow passage; The dual-function compensator has a movable sealing member disposed in the elongated body for at least initially being disposed in a first position adjacent the first end of the elongated body and preventing fluid flow through the elongated body and movable to a second position enabling fluid flow through the elongated body; The dual-function compensator further includes: a retainer member for securing the movable sealing member in the first position, wherein the retainer member is further configured to release the movable sealing member from being secured in the first position so that the movable sealing member can move according to a fluid pressure difference between the inner cavity of the drill bit body and the flow passage, and wherein, after fluid is discharged from the dual-function compensator, the movable sealing member is disposed in the second position within the elongated body of the dual-function compensator, the movable sealing member being located on one side of a flow passage for transferring fluid flow from the inner cavity of the drill bit body to the flow passage; The drill bit body also includes a flow passage through the drill bit body having a terminal end adjacent to the inner cavity of the drill bit body, the terminal end defining a compensator port, wherein the compensator port is larger than the cross-sectional dimensions of the remainder of the flow passage, and the compensator tube has a lower end extending into the compensator port; and wherein the compensator port is sized to interface with the dual-function compensator, a gap is provided between the dual-function compensator and the compensator port, and the gap is sized to allow fluid to flow from the inner cavity of the drill bit body to the flow passage; Also included are a through hole provided on the side wall of the elongated body for allowing drilling fluid to enter the elongated body from the inner cavity of the drill body through the through hole, and a hole through the side wall of the elongated body for allowing drilling fluid to enter the flow channel from the elongated body, wherein the through hole, the hole, the flow channel and the intermediate space between the journal and the rotating cone are sized to allow drilling fluid to pass through; the movable sealing member having a movable sealing body and an upwardly extending stem about which a seal is mounted, the upwardly extending stem having a retaining port for receiving the retainer member; and wherein the retainer member includes a removable pin extending through two opposing through-holes in the elongated body and through the retaining port for securing the movable sealing member in the first position; The dual-function compensator has a flange extending outwardly from a middle portion of the dual-function compensator, and the flange engages the compensator port disposed at a terminal end of the flow passage and positions the dual-function compensator at the compensator port.

5. The mining drill bit according to claim 4, characterized in that: The flange is welded to the drill bit body to secure the first end of the dual-function compensator to the compensator port.

6. The mining drill bit according to claim 4, characterized in that: An elastomeric seal is provided between the dual-function compensator and the compensator port for sealing engagement therebetween.

7. A mining drill bit, characterized in that: include: a drill bit body, with at least one journal mounted on the drill bit body; A rotating cone is mounted on the journal for rotation, and an intermediate space is defined between the rotating cone and the journal; The seal is provided between the journal and the rotating cone to seal the intermediate space outside the drill bit; An oil storage cavity is defined by a combination of the compensator port, the grease flow channel, the grease port, and the ball port; a fill port and a drain port connect the oil storage cavity to the outside of the tooth palm and between the drill bit; The flow passage extends from the inner cavity of the drill body to the intermediate space between the journal and the rotating cone; a dual-function compensator extending between the flow passage and the inner cavity of the drill bit body, the dual-function compensator comprising a tubular body having a first end in fluid communication with the inner cavity of the drill bit body and a second end in fluid communication with the flow passage; The dual-function compensator has a piston disposed in the tubular body for at least initially being disposed in a first position adjacent the first end of the tubular body and preventing fluid flow through the tubular body and movable to a second position enabling fluid flow through the tubular body; The dual-function compensator further includes: a retainer member for fixing the piston in the first position, wherein the retainer member is further configured to release the piston from being fixed in the first position so that the piston can move according to a fluid pressure difference between the inner cavity of the drill bit body and the flow channel, wherein after the fluid is discharged from the dual-function compensator, the piston is disposed in the second position within the tubular body of the dual-function compensator on one side of a flow channel for transferring fluid flow from the inner cavity of the drill bit body to the flow channel; wherein the tubular body of the dual-function compensator has a through hole extending through a side wall of the tubular body for allowing fluid to flow between the interior of the tubular body and the inner cavity of the drill bit body, and a hole extending through the interior of the tubular body and the flow channel for allowing fluid to flow between the interior of the tubular body and the flow channel, wherein the through hole, the hole, the flow channel and the intermediate space between the journal and the rotating cone are sized for passage of drilling fluid; The drill bit body also includes a flow passage through the drill bit body having a terminal end adjacent to the inner cavity of the drill bit body, the terminal end defining a compensator port, wherein the compensator port is larger than the cross-sectional dimensions of the remainder of the flow passage, and the compensator tube has a lower end extending into the compensator port; and wherein the compensator port is sized to interface with the dual-function compensator, a gap is provided between the dual-function compensator and the compensator port, and the gap is sized to allow fluid to flow from the inner cavity of the drill bit body to the flow passage; Also included are a through hole provided on the side wall of the tubular body for allowing drilling fluid to enter the tubular body from the inner cavity of the drill body through the through hole, and a hole through the side wall of the tubular body for allowing drilling fluid to enter the flow channel from the tubular body, wherein the through hole, the hole, the flow channel and the intermediate space between the journal and the rotating cone are sized to allow drilling fluid to pass through; the piston having a piston body and an upwardly extending stem, a seal mounted about the body, the upwardly extending stem having a retaining port for receiving the retainer member; and wherein the retainer member includes a removable pin extending through two opposing through-holes and through the retaining port for securing the piston in the first position; The dual-function compensator has a flange extending outwardly from a middle portion of the dual-function compensator, and the flange is engaged with a terminal end of the flow channel and positions the dual-function compensator in the cavity of the flow channel.

8. The mining drill bit according to claim 7, characterized in that: The flange is welded to the drill bit body to secure the first end of the dual-function compensator to the compensator port.

9. The mining drill bit according to claim 7, characterized in that: An elastomeric seal is provided between the dual-function compensator and the compensator port for sealing engagement therebetween.

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