A reverse circulation drill bit

Abstract

The present invention provides a reverse circulation drill bit comprising a drill bit body having a central air hole, a cavity, and a flow guide machined into the center of the drill bit body; the flow guide is disposed between the central air hole and the cavity, and the cavity cooperates with a collection tube. The drill bit employing this structure effectively prevents rock samples from impacting the end face of the collection tube, thereby increasing the service life of the collection tube; reduces energy loss during rock sample collection, improves rock sample collection efficiency, and ensures the integrity of the rock sample.

Description

Technical Field

[0001] The invention relates to a reverse circulation drill bit, belonging to the technical field of drill bits. Background Art

[0002] Reverse circulation drilling and down-the-hole drilling are common drilling techniques. Both utilize an impactor paired with a corresponding drill bit. The most significant feature of reverse circulation drilling is that rock dust is expelled from the impactor to the surface, effectively protecting the hole walls and efficiently collecting rock particles. It is widely used in prospecting, mining, and other engineering projects.

[0003] Figure 1 Figure 2 is a schematic diagram of dust removal during the operation of a common reverse circulation hammer and reverse circulation drill bit. During operation, compressed gas is blown to the bottom of the hole along the air channel a on the outer edge of the reverse circulation drill bit. The compressed gas and the rock sample are collected from the bottom of the hole through the air hole b on the end face of the drill bit, the central air hole c, the hole cavity d, the central air hole e of the collection tube 22, and the central air hole m of the adapter tube 23. The adapter tube 23 is connected to an external rock sample collection device. The rock sample completes the process from the bottom of the hole through the internal channel of the reverse circulation drill bit 1 and the hammer 2 to the collection device. The entire process is the "outside-to-inside" center hole reverse circulation process of the rock sample in reverse circulation drilling.

[0004] Figure 2 This is an enlarged schematic diagram of the fluid flow at the interface between the drill bit cavity d and the collection tube 22. A mixture of compressed gas and rock sample flows through the central channel c and cavity d, rushing to the end face of the collection tube, forming a vortex. This creates a localized loss of mechanical energy and reduces rock dust collection efficiency. This impact with the end face of the collection tube reduces the size of the rock sample, affecting its quality and accelerating wear on the collection tube and the hole where the drill bit meets it. Summary of the Invention

[0005] The purpose of the present invention is to provide a reverse circulation drill bit. By adopting the drill bit with the above structure, the impact of rock samples on the end face of the collection tube is effectively avoided, thereby increasing the service life of the collection tube; reducing energy loss during rock sample collection, improving rock sample collection efficiency; and ensuring the integrity of the rock sample.

[0006] In order to realize the above-mentioned technical features, the purpose of the present invention is realized as follows: a reverse circulation drill bit, which includes a drill bit body, the center of which is processed with a central air hole, a cavity and a guide portion; the guide portion is a cavity whose cross-section gradually increases from the end of the central air hole and then gradually decreases, and is arranged between the central air hole and the cavity, and the cavity cooperates with the collection pipe.

[0007] The extension line of the side wall of the guide portion can pass through the structure of the end surface of the collecting pipe, so that the fluid moves along the side wall of the guide portion toward the collecting pipe.

[0008] The side wall of the guide portion is extended to the end surface of the collecting pipe, and the diameter H2≤H1, wherein H1 is the inner diameter of the collecting pipe.

[0009] An impactor comprising any one of the reverse circulation drill bits, wherein the impactor adopts the reverse circulation drill bit.

[0010] The present invention has the following beneficial effects:

[0011] 1. By adopting the drill bit with the above structure, the impact of the rock sample on the end face of the collection tube is effectively avoided, thereby increasing the service life of the collection tube.

[0012] 2. Through the diversion function of the diversion part, the rock sample can be guided to directly enter the collection pipe, reducing energy loss during rock sample collection and improving rock sample collection efficiency.

[0013] 3. The above-mentioned guide part prevents the rock sample from directly contacting and impacting the end face of the collection tube, thereby ensuring the integrity of the rock sample.

[0014] 4. By adopting the drill bit with the above structure, the wear of the rock sample on the hole between the drill bit and the collection tube is effectively reduced, thereby increasing the service life of the drill bit. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The present invention will be further described below with reference to the accompanying drawings and examples.

[0016] Figure 1 This is a schematic diagram of powder discharge when an existing reverse circulation hammer and reverse circulation drill are working.

[0017] Figure 2 This is an enlarged schematic diagram of the fluid at the junction of the existing drill bit cavity and the collection tube.

[0018] Figure 3 It is a schematic diagram of the drill bit structure of the present invention.

[0019] Figure 4 This is a schematic diagram of powder discharge during operation of the reverse circulation hammer and reverse circulation drill bit of the present invention.

[0020] Figure 5 This is a partial enlarged view of the powder discharge of the reverse circulation hammer and reverse circulation drill bit of the present invention when they are working.

[0021] Figure 6 It is an enlarged schematic diagram of the fluid at the joint between the drill bit cavity and the collection tube of the present invention. DETAILED DESCRIPTION

[0022] The embodiments of the present invention will be further described below with reference to the accompanying drawings.

[0023] Example 1:

[0024] See also Figure 3-6A reverse circulation drill bit includes a drill bit body 1, the center of which is processed with a central air hole c, a cavity f and a guide part v; the guide part v is a cavity whose cross-section gradually increases from the end of the central air hole c and then gradually decreases, and is arranged between the central air hole c and the cavity f, and the cavity f cooperates with the collection pipe 22.

[0025] Furthermore, the extension line L1 of the side wall L of the guide portion v can pass through the structure of the collecting pipe end surface D, so that the fluid moves along the side wall of the guide portion v toward the collecting pipe 22, thereby reducing direct contact between the fluid and the collecting pipe end surface D.

[0026] Furthermore, the side wall L of the guide portion v is extended to the end face D of the collecting tube with a diameter H2≤H1, where H1 is the inner diameter of the collecting tube 22, thereby preventing the rock sample from directly contacting the end face of the collecting tube.

[0027] The principle of powder removal when using the reverse circulation drill bit with the above structure and the hammer is:

[0028] During operation, compressed gas is blown to the bottom of the hole along the air channel a on the outer edge of the reverse circulation drill bit. The compressed gas and the rock sample are collected through the bottom of the hole through the air hole b on the end face of the drill bit, the central air hole c, the guide part v, the central air hole e of the collection pipe 22 and the central air hole m of the adapter pipe 23. The adapter pipe 23 is connected to the external rock sample collection equipment. The rock sample completes the process from the bottom of the hole through the internal channel of the reverse circulation drill bit 1 and the impactor 2 to the collection equipment.

Claims

1. A reverse circulation drill bit, characterized by: It comprises a drill bit body (1), the center of which is machined with a central air hole (c), a cavity (f) and a guide portion (v); the guide portion (v) is a cavity whose cross section gradually increases from the end of the central air hole (c) and then gradually decreases, and is arranged between the central air hole (c) and the cavity (f); the cavity (f) cooperates with a collecting pipe (22); An extension line (L1) of the side wall (L) of the guide portion (v) can pass through the structure of the collecting pipe end surface (D), so that the fluid moves along the side wall of the guide portion (v) toward the collecting pipe (22).

2. A reverse circulation drill bit according to claim 1, characterized in that: The side wall (L) of the guide portion (v) is extended to the end surface (D) of the collecting pipe, and the diameter H2≤H1, wherein H1 is the inner diameter of the collecting pipe (22).

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