Double-wall check joint for reverse circulation drilling

Abstract

The utility model discloses a reverse circulation drilling double-wall check connector which is installed between two double-wall drill rods and comprises an outer connector, an inner connector, an annular valve element and a spring, and the outer connector and the inner connector inside the outer connector are distributed at intervals and connected to form an annular valve cavity. The inner joint is provided with an annular groove; the annular valve element is located in the annular valve cavity and slidably connected. The spring is located in the annular valve cavity, and the two ends of the spring abut against the annular valve element and the first step of the annular valve cavity correspondingly, so that the annular valve element corresponds to the annular groove in position when the spring is compressed. One-way plugging is formed for the annular space of the inner pipe and the outer pipe of the double-wall drill rod, compressed air can be prevented from escaping when the drill rod is added, the air conveying time is shortened, and the drilling efficiency is improved.

Description

Technical Field

[0001] This utility model relates to the field of drilling tools technology, and more specifically to a double-walled check joint for reverse circulation drilling. Background Technology

[0002] In air reverse circulation drilling or air lift reverse circulation drilling, compressed air enters the bottom of the hole through the annular gap between the inner and outer tubes of the double-walled drill pipe, achieving reverse circulation. To meet the overall length requirements of the drill pipe, multiple double-walled drill pipes are usually connected together.

[0003] However, each time a double-walled drill pipe is added, the compressed air in the annular gap between the inner and outer pipes of the double-walled drill pipe needs to be disassembled because two adjacent double-walled drill pipes need to be disassembled. After the new double-walled drill pipe is connected, the air compressor needs to supply air for 5-10 minutes to re-establish the reverse circulation, which is time-consuming and energy-intensive, and seriously affects drilling efficiency.

[0004] Therefore, providing a reverse circulation drilling double-wall check joint is a problem that urgently needs to be solved by those skilled in the art. Utility Model Content

[0005] In view of this, the present invention provides a reverse circulation drilling double-wall check joint to solve the aforementioned technical problems.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A reverse circulation drilling double-wall check joint, installed between two double-wall drill pipes, includes an outer joint, an inner joint, an annular valve core, and a spring. The outer joint and the inner joint inside it are spaced apart and connected to form an annular valve cavity. The inner joint has an annular groove. The annular valve core is located in the annular valve cavity and is slidably connected. The spring is located in the annular valve cavity and its two ends abut against the annular valve core and the first step of the annular valve cavity, respectively, so that when the spring is compressed, the annular valve core corresponds to the position of the annular groove.

[0008] By adopting the above technical solutions, the beneficial effects of this utility model are as follows:

[0009] The one-way sealing of the annular gap between the inner and outer pipes of the double-walled drill pipe can prevent compressed air from escaping when adding drill pipe, shorten the gas delivery time, and improve drilling efficiency.

[0010] Furthermore, a first retaining ring is installed at the upper end of the annular valve cavity to restrict the annular valve core from extending out of the annular valve cavity.

[0011] The beneficial effect of adopting the above-mentioned further technical solution is that it limits the movement of the annular valve core, preventing the annular valve core from detaching from the annular valve cavity.

[0012] Furthermore, the inner connector is connected to the outer connector through a plurality of support blocks evenly spaced around its periphery, and the lower end of each support block abuts against the second step of the annular valve cavity; an air flow channel is formed between two adjacent support blocks.

[0013] The beneficial effect of adopting the above-mentioned further technical solution is that, while ensuring the stability of the support, it can also minimize the impact on the cross-section of the annular gap channel and reduce the resistance to compressed air flow.

[0014] Furthermore, a second retaining ring is installed at the front end of the annular valve chamber located on the support block.

[0015] The beneficial effect of adopting the above-mentioned further technical solution is that it limits the support block and prevents it from moving up and down.

[0016] Furthermore, the annular groove is an arc-shaped annular groove.

[0017] The beneficial effect of adopting the above-mentioned further technical solution is to improve the smoothness of compressed air flow.

[0018] Furthermore, sealing rings are installed between the annular valve core and the inner connector, as well as between the annular valve core and the outer connector.

[0019] The beneficial effect of adopting the above-mentioned further technical solution is to improve sealing performance.

[0020] Furthermore, the inner connector has a first sealing groove on the outer side of the upper end of the annular groove that contacts the annular valve core, and the annular valve core has a second sealing groove on the outer side that contacts the outer connector. The sealing ring is installed in both the first sealing groove and the second sealing groove.

[0021] The beneficial effect of adopting the above-mentioned further technical solution is to avoid reducing the air flow area between the annular groove and the annular valve core.

[0022] Furthermore, the sealing ring is a rubber sealing ring. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0024] Figure 1 The attached figure is a structural schematic diagram of the closed state of a reverse circulation drilling double-wall check joint provided by this utility model;

[0025] Figure 2 The attached figure is a structural schematic diagram of the reverse circulation drilling double-wall check joint in the open state provided by this utility model;

[0026] Figure 3 The attached figure is a structural schematic diagram of the relationship between the reverse circulation drilling double-wall check joint and the double-wall drill pipe provided by this utility model. Detailed Implementation

[0027] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0028] like Figure 1-3 As shown in the figure, this utility model discloses a reverse circulation drilling double-wall check valve joint, installed between two double-wall drill pipes 1. It includes an outer connector 2, an inner connector 3, an annular valve core 4, and a spring 5. The outer connector 2 and its inner connector 3 are spaced apart and connected to form an annular valve cavity 6. The inner connector 3 has an annular groove 31. The annular valve core 4 is located within the annular valve cavity 6 and is slidably connected. The spring 5 is located within the annular valve cavity 6, with both ends abutting against the annular valve core 4 and the first step of the annular valve cavity 6, respectively, so that when the spring is compressed, the annular valve core 4 corresponds to the position of the annular groove 31. This utility model forms a unidirectional seal for the annular gap between the inner and outer pipes of the double-wall drill pipe 1, which can prevent compressed air from escaping when adding double-wall drill pipes, shorten the air delivery time, and improve drilling efficiency.

[0029] Specifically, the upper end of the outer connector 2 and the upper end of the inner connector 3 form an upper interface, and the lower end of the outer connector 2 and the lower end of the inner connector 3 form a lower interface. The upper interface is connected to the double-walled drill rod 1 located at the top, and the lower interface is connected to the double-walled drill rod 1 located at the bottom.

[0030] To further optimize the technical solution of this utility model, a first retaining ring 7 is installed at the upper end of the annular valve cavity 6 to restrict the annular valve core 4 from extending out of the annular valve cavity 6, thereby limiting the annular valve core 4 and preventing the annular valve core 4 from detaching from the annular valve cavity 6.

[0031] Of course, the outer connector 2 has a first snap ring groove, the first snap ring 7 is installed in the first snap ring groove, and there is an air flow gap between the first snap ring 7 and the inner connector 3.

[0032] To further optimize the technical solution of this utility model, the inner connector 3 is connected to the outer connector 2 through a plurality of support blocks 8 evenly spaced around its periphery, and the lower end of each support block 8 abuts against the second step of the annular valve cavity 4; an air flow channel is formed between two adjacent support blocks 8. In this embodiment, there are four support blocks 8, which can ensure stable support while minimizing the impact on the cross section of the annular channel and reducing the resistance to compressed air flow.

[0033] To further optimize the technical solution of this utility model, a second retaining spring 9 is installed at the front end of the annular valve cavity 6 on the support block 8 to limit the support block 8 and prevent it from moving up and down.

[0034] Of course, the outer connector 2 has a second snap ring groove, the second snap ring 9 is installed in the second snap ring groove, and there is an air flow gap between the second snap ring 9 and the inner connector 3.

[0035] To further optimize the technical solution of this utility model, the annular groove 31 is an arc-shaped annular groove, which can improve the smoothness of compressed air flow.

[0036] To further optimize the technical solution of this utility model, sealing rings 10 are installed between the annular valve core 4 and the inner connector 3, and between the annular valve core 4 and the outer connector 2, which can improve the sealing performance.

[0037] Specifically, the inner connector 3 has a first sealing groove on the outer side of the upper end of the annular groove 31 that contacts the annular valve core 4, and the annular valve core 4 has a second sealing groove on the outer side that contacts the outer connector 2. Both the first and second sealing grooves are equipped with sealing rings 10 to avoid reducing the air flow area between the annular groove 31 and the annular valve core 4.

[0038] Specifically, the sealing ring 10 is a rubber sealing ring.

[0039] The working principle of this utility model:

[0040] In the unloaded state, the annular valve core 4 is lifted by the spring force of the spring 5, and the annular valve core 4 is in contact with the inner connector 3 and the outer connector 2, and is in a closed state (no air flow). During drilling, the air compressor inputs high-pressure air. Under the action of air pressure, the annular valve core 4 overcomes the spring force of the spring 5 and moves downward. When it moves to the position of the annular groove 31, a compressed air flow space is formed between the annular valve core 4 and the annular groove 31. The compressed air enters the annular gap between the inner and outer pipes of the double-wall drill pipe 1 and establishes a reverse circulation. After drilling stops, the air compressor stops supplying air, and the annular valve core 4 returns to its position under the action of the spring force of the spring 5, and is closed again. The compressed air in the annular gap is pressurized.

[0041] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0042] The above description of the disclosed embodiments enables those skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A reverse circulation drilling double-wall check joint installed between two double-wall drill pipes, characterized in that, The valve comprises an outer joint, an inner joint, a ring-shaped valve core and a spring. The outer joint is spaced apart from the inner joint and connected to form a ring-shaped valve cavity. The inner joint has a ring-shaped groove. The ring-shaped valve core is located in the ring-shaped valve cavity and is connected slidingly. The spring is located in the ring-shaped valve cavity and has two ends abutting against the ring-shaped valve core and a first step of the ring-shaped valve cavity respectively. In the compressed state of the spring, the ring-shaped valve core corresponds to the position of the ring-shaped groove.

2. A double-wall check sub for reverse circulation drilling as set forth in claim 1, wherein, A first snap spring is installed at the upper end of the ring-shaped valve cavity to limit the extension of the ring-shaped valve core out of the ring-shaped valve cavity.

3. A double-wall check sub for reverse circulation drilling as set forth in claim 1, wherein, The inner joint is connected to the outer joint through a plurality of support blocks uniformly spaced apart around the periphery of the inner joint. The lower end of each support block abuts against a second step of the ring-shaped valve cavity. An air flow channel is formed between two adjacent support blocks.

4. A double-wall check sub for reverse circulation drilling as set forth in claim 3, wherein, A second snap spring is installed at the front end of the ring-shaped valve cavity.

5. The double-wall check sub of claim 1, wherein: The ring-shaped groove is an arc-shaped ring-shaped groove.

6. A double-wall check sub for reverse circulation drilling as defined in claim 1, wherein A sealing ring is installed between the ring-shaped valve core and the inner joint and between the ring-shaped valve core and the outer joint.

7. A double-wall check sub for reverse circulation drilling as set forth in claim 6, characterized in that, The inner joint has a first sealing groove on the outer side of the upper end of the ring-shaped groove in contact with the ring-shaped valve core. The ring-shaped valve core has a second sealing groove on the outer side in contact with the outer joint. The first sealing groove and the second sealing groove are both provided with the sealing ring.

8. A double-wall check sub for reverse circulation drilling as set forth in claim 7, characterized in that, The sealing ring is a rubber sealing ring.

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