A back-flushing filter drill pipe for use in coal mines and a method of using the same

Abstract

The present application belongs to the field of drilling tools, and relates to a coal mine underground back-flushing filter drill rod and a use method thereof. The coal mine underground back-flushing filter drill rod comprises a drill rod body, the drill rod body is composed of an upper outer tube and a lower outer tube, a throttle block, an upper inner tube, a filter tube fixing seat and a lower inner tube are sequentially arranged in the upper outer tube, a cone valve core and a control spring are sequentially arranged in the upper inner tube, the upper inner tube, the filter tube fixing seat and the lower inner tube are respectively provided with an annular flow channel between the upper inner tube and the upper outer tube, a filter core, a pressure valve core, an unloading spring and a spring gland are sequentially arranged in the lower outer tube, and the filter core is fixed through the filter tube fixing seat. Nozzles are embedded in the upper outer tube and the upper inner tube, annular B and annular C are arranged at two ends of the cone valve core, annular B and annular A are arranged at two ends of the filter core, annular A and annular C are communicated through the annular flow channel, and annular B is communicated with the outside through the nozzles. The present application utilizes the flow change in the starting stage of the pump, realizes the reverse flushing of the filter device, discharges the rock debris to the outside, and ensures that the filter device is not blocked for a long time.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of drilling tools, and relates to a coal mine underground back-flushing filter drill rod and a use method thereof. BACKGROUND

[0002] The hydraulic hammer has extremely high requirements for the cleanliness of drilling fluid. However, after adding the drill rod each time, a large amount of cuttings is brought in the newly added drill rod. The cuttings in the drill rod reaches the inside of the hydraulic hammer along with the drilling fluid. The drilling fluid with the cuttings causes the service life of the hydraulic hammer to be very short. According to statistics, the wear of the hydraulic hammer after working in the well for 6 hours is equivalent to the wear after working in clean water for 80-100 hours. The cuttings in the newly added drill rod seriously affects the drilling efficiency and causes a large amount of economic loss. In order to filter the cuttings brought by the disassembled drill rod, a filter device is added behind the hydraulic hammer. However, the impurities in the filter device cannot be discharged in time. The pressure difference before and after the filter device is increased, which causes the filter core to be damaged. The scheme of adding the filter device behind the hydraulic hammer cannot filter the cuttings in the drill rod for a long time. Therefore, a filter device capable of self-cleaning is needed. SUMMARY

[0003] In view of this, the purpose of the present application is to provide a coal mine underground back-flushing filter drill rod and a use method thereof. The flow change in the pump starting stage is relied on to realize the back-flushing of the filter device and discharge the cuttings, ensure the cleanliness of the filter core of the filter device, and realize the long-time use of the filter device without blocking the filter core.

[0004] To achieve the above purpose, the present application provides the following technical scheme: a coal mine underground back-flushing filter drill rod, comprising a drill rod body, the drill rod body is composed of an upper outer pipe and a lower outer pipe, a throttle block, an upper inner pipe, a filter pipe fixing seat and a lower inner pipe are sequentially arranged in the upper outer pipe, a cone valve core and a control spring are sequentially arranged in the upper inner pipe, an annular flow channel is arranged between the upper inner pipe, the filter pipe fixing seat, the lower inner pipe and the upper outer pipe, a filter core, a pressure valve core, an unloading spring and a spring gland are sequentially arranged in the lower outer pipe, and the filter core is fixed through the filter pipe fixing seat;

[0005] A nozzle is further embedded in the upper outer pipe and the upper inner pipe, annular B and annular C are arranged at both ends of the cone valve core, annular B and annular A are arranged at both ends of the filter core, annular A and annular C are kept in communication through the annular flow channel, and annular B is communicated with the outside through the nozzle.

[0006] Optionally, the annular flow channel is a plurality of grooves formed on the outer surfaces of the upper inner pipe, the filter pipe fixing seat and the lower inner pipe. The grooves are arranged in the direction of the drill rod, and the corresponding grooves on the upper inner pipe, the filter pipe fixing seat and the lower inner pipe are communicated with each other.

[0007] Optionally, the nozzle is arranged below the limit position of the spool, and the nozzle is between the sealing rings of the spool when the spool is in the lower limit position, and the nozzle remains closed.

[0008] Optionally, a throttling channel is arranged in the throttling block, the cross section of the throttling channel is smaller than the cross section of the internal flow passage of the upper outer tube, and a throttling effect is formed when the fluid flows through the throttling channel, so that the pressure at the upper end of the throttling block is greater than the pressure at the lower end.

[0009] A use method of the coal mine underground back-flushing filter drill rod, which is suitable for the coal mine underground back-flushing filter drill rod, and comprises the following steps:

[0010] A, when drilling, drilling fluid is provided in the drill rod, the drilling fluid passes through the throttling block, a throttling channel is arranged in the throttling block, a throttling effect is formed at both ends of the throttling block, and a pressure difference is formed at both ends of the throttling block, the pressure at the upper end is greater than the pressure at the lower end, the fluid pressure at the upper end of the throttling block is P1, the fluid pressure at the lower end of the throttling block is P2, P1 is greater than P2, therefore, the throttling block is subjected to the downward differential pressure, the throttling block is set to be static when the flow is less than the set value Q1, and the throttling mechanism moves downward when the flow is greater than Q1;

[0011] B, back-flushing of the filter drill rod: after the pump is started, the flow continues to increase until the rated flow, during the 0-Q1 flow stage after the pump is started, the drilling fluid passes through the throttling block, a throttling effect is formed at both ends of the throttling block, and a pressure difference is formed at both ends of the throttling block, the downward force of the pressure difference acting on the throttling block is insufficient to overcome the upward elastic force provided by the control spring, the throttling block and the spool are in the upper limit position, the spool blocks the channel between the annulus C and the annulus B, and since the pressure formed by the flow Q1 on the pressure spool is less than the elastic force of the unloading spring, the pressure spool blocks the downward flow passage, the drilling fluid can only enter the annulus C after back-flushing the filter element from the annulus C through the annulus flow passage and the annulus A, and finally is discharged to the external space through the nozzle;

[0012] C, normal drilling operation: when the flow is Q2, the flow Q2 is greater than Q1, a pressure difference is formed at both ends of the throttling block, the downward force of the pressure difference acting on the throttling block is sufficient to overcome the upward elastic force provided by the control spring, the throttling block and the spool move downward, the annulus flow passage is blocked by the throttling block, the nozzle is blocked by the spool, the fluid pressure rapidly increases, the pressure on the pressure spool overcomes the elastic force of the unloading spring, the pressure spool moves downward, the annulus C and the annulus B are connected, the fluid enters the annulus B from the annulus C, passes through the filter element, enters the annulus A, and finally enters the lower equipment through the pressure spool from the annulus A, so that the filtering of the drilling fluid is realized.

[0013] Optionally, the elastic force of the control spring arranged below the spool is equal to the pressure difference force formed by the flow Q1 at both ends of the spool.

[0014] Optionally, the elastic force of the unloading spring is greater than the pressure formed by the flow Q1 on the pressure spool.

[0015] The coal mine underground back-flushing filter drill rod and the use method thereof have the advantages that the flow change in the initial stage of the pump is utilized to realize the reverse flushing of the filter device and to discharge the rock debris to the outside, and the filter device is ensured to be not blocked for a long time.

[0016] Additional advantages, objects, and features of the application will be set forth in part by the description that follows, and in part will become apparent to those skilled in the art upon examination of same, or can be learned by practice of the application. The objects and other advantages of the application can be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings. BRIEF DESCRIPTION OF DRAWINGS

[0017] To make the objects, technical solutions and advantages of the present application clearer, the preferred embodiments of the present application will be described in detail below with reference to the drawings, in which:

[0018] Figure 1 is a schematic diagram of the reverse flushing state of the present application;

[0019] Figure 2 is a schematic diagram of the filtering state of the present application;

[0020] Figure 3 is Figure 1 is a sectional view of A-A in FIG. 1.

[0021] The drawings show the following: 1, upper outer pipe; 2, spool valve core; 3, nozzle; 4, filter pipe fixing seat; 5, filter core; 6, pressure valve core; 7, unloading spring; 8, spring gland; 9, lower outer pipe; 10, annulus flow channel; 11, lower inner pipe; 12, control spring; 13, upper inner pipe; 14, throttle block; 101, annulus A; 102, annulus B; 103, annulus C. DETAILED DESCRIPTION

[0022] The embodiments of the present application are described below through specific concrete examples, and those skilled in the art can easily understand other advantages and effects of the present application from the disclosure of the present specification. The present application can also be implemented or applied through other different specific embodiments, and each detail in the present specification can be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that the diagrams provided in the following embodiments only illustrate the basic concept of the present application in a schematic manner, and the following embodiments and features in the embodiments can be combined with each other without conflict.

[0023] The drawings are only used for exemplary illustration, and the representation is only a schematic diagram, not a physical diagram, and cannot be understood as a limitation on the present application; in order to better illustrate the embodiments of the present application, some components of the drawings may be omitted, enlarged or reduced, and do not represent the size of the actual product; for those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0024] The same or similar reference numerals in the drawings of the embodiments of the present application correspond to the same or similar components; in the description of the present application, it should be understood that if the terms "upper", "lower", "left", "right", "front", "back" and the like indicate the orientation or positional relationship shown in the drawings, they are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore the terms describing the positional relationship in the drawings are only used for exemplary illustration, and cannot be understood as a limitation on the present application, for those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0025] Please refer to Figures 1 to 3 , a coal mine underground backwash filter drill rod, comprising a drill rod body, the drill rod body is composed of an upper outer tube 1 and a lower outer tube 9, a throttle block 14, an upper inner tube 13, a filter tube fixing seat 4 and a lower inner tube 11 are sequentially arranged in the upper outer tube 1, a cone valve core 2 and a control spring 12 are sequentially arranged in the upper inner tube 13, the upper inner tube 13, the filter tube fixing seat 4 and the lower inner tube 11 are respectively provided with an annular flow channel 10 between the upper outer tube 1, a filter core 5, a pressure valve core 6, an unloading spring 7 and a spring gland 8 are sequentially arranged in the lower outer tube 9, the filter core 5 is fixed through the filter tube fixing seat 4, a nozzle 3 is embedded in the upper outer tube 1 and the upper inner tube 13, annular spaces B102 and C103 are provided at both ends of the cone valve core 2, annular spaces B102 and A101 are provided at both ends of the filter core, the annular space A101 and the annular space C103 are kept in communication through the annular flow channel 10, the annular space B102 is communicated with the outside through the nozzle 3, the annular flow channel 10 is a plurality of grooves formed on the outer surfaces of the upper inner tube 13, the filter tube fixing seat 4 and the lower inner tube 11, the grooves are arranged along the direction of the drill rod, and the corresponding grooves on the upper inner tube 13, the filter tube fixing seat 4 and the lower inner tube 11 are communicated with each other, the nozzle 3 is arranged below the extreme position of the cone valve core 2, when the cone valve core 2 is at the lower extreme position, the nozzle 3 is between the sealing rings of the cone valve core, the nozzle 3 is kept closed, a throttling channel is arranged in the middle of the throttle block 14, the cross section of the throttling channel is smaller than that of the inner flow channel of the upper outer tube, when the fluid flows through the throttling channel, a throttling effect is formed, so that the pressure at the upper end of the throttle block 14 is greater than that at the lower end.

[0026] In order to facilitate the understanding of the structure diagram of the present patent, according to Figure 1 the placement direction, the present patent is described as follows:

[0027] When drilling, drilling fluid needs to be provided inside the drill pipe. The drilling fluid passes through the throttle block, a throttle passage is arranged inside the throttle block 14, a throttling effect is formed at both ends of the throttle block, a pressure difference is formed at both ends of the throttle block 14, and the pressure at the upper end is greater than that at the lower end. The fluid pressure at the upper end of the throttle block 14 is P1, and the fluid pressure at the lower end of the throttle block 14 is P2. Therefore, P1 is greater than P2, and the throttle block 14 is subjected to a downward pressure difference.

[0028] It should be noted that the throttling effect is that the gas or liquid passing through the cross section inside the pipeline is suddenly blocked, and the fluid generates vortex, collision and friction at the contraction cross section. Therefore, the pressure after the contraction cross section is much lower than that before the contraction cross section.

[0029] Reverse flushing of the filter drill pipe: After the pump is started, the flow continues to rise until the rated flow. During the 0-Q1 flow stage after the pump is started, the drilling fluid passes through the throttle block, a throttling effect is formed at both ends of the throttle block 14, and a pressure difference is formed at both ends of the throttle block 14. The downward force of the pressure difference acting on the throttle block 14 is insufficient to overcome the upward elastic force provided by the control spring 12. The throttle block 14 and the cone valve core 2 are in the upper limit position, and the cone valve core 2 blocks the passage between the annulus C103 and the annulus B102. Since the pressure formed by the flow Q1 on the pressure valve core 6 is less than the elastic force of the unloading spring 7, the pressure valve core 6 blocks the downward flow channel. The drilling fluid can only enter the annulus C103 after reverse flushing the filter element 5 through the annulus flow channel 10 and the annulus A101, and finally be discharged to the outside space through the nozzle.

[0030] Normal drilling operation: when the flow is Q2, Q2 is greater than Q1, a pressure difference is formed at both ends of the throttle block 14, and the downward force of the pressure difference acting on the throttle block 14 is sufficient to overcome the upward elastic force provided by the control spring 12. The throttle block 14 and the cone valve core 2 move downward, the annulus flow channel 10 is blocked by the throttle block 14, the nozzle 3 is blocked by the cone valve core 2, the fluid pressure rises rapidly, the pressure on the pressure valve core 6 overcomes the elastic force of the unloading spring 7, and the pressure valve core 6 moves downward. The annulus C103 and the annulus B102 are connected, the fluid enters the annulus B102 from the annulus C103, passes through the filter element 5, enters the annulus A101, and finally enters the lower equipment from the annulus A through the pressure valve core 6, thereby realizing the filtration of the drilling fluid.

[0031] In the embodiment, the control spring 12 is arranged below the cone valve core 2, and the elastic force of the control spring 12 is equal to the pressure difference force formed by the flow Q1 at both ends of the core column. The elastic force of the unloading spring 7 is greater than the pressure formed by the flow Q1 on the pressure valve core 6.

[0032] Finally, it is to be explained that the above embodiments are only used to illustrate the technical solutions of the present application but not to limit the present application. Although the present application is described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solutions of the present application can be modified or equivalently replaced without departing from the purpose and scope of the technical solutions, and all should be covered in the scope of the claims of the present application.

Claims

1. A back-flushing filter drill rod for use in a coal mine, characterised in that: The drill pipe body consists of an upper outer tube and a lower outer tube. The upper outer tube contains a throttling block, an upper inner tube, a filter tube fixing seat, and a lower inner tube. The upper inner tube also contains a cone valve core and a control spring. Annular flow channels are provided between the upper inner tube, the filter tube fixing seat, the lower inner tube, and the upper outer tube. The lower outer tube contains a filter element, a pressure valve core, an unloading spring, and a spring cap. The filter element is fixed by the filter tube fixing seat. The upper outer tube and the upper inner tube are also embedded with nozzles. The cone valve core is provided with annular space B and annular space C at both ends. The filter element is provided with annular space B and annular space A at both ends. The annular space A and annular space C are connected through the annular space flow channel. The annular space B is connected to the outside through the nozzle.

2. A back-flushing filter drill rod for use in a coal mine, according to claim 1, wherein: The annular flow channel consists of multiple grooves on the outer surfaces of the upper inner tube, the filter tube fixing seat, and the lower inner tube. The grooves are arranged along the drill rod direction, and the corresponding grooves on the upper inner tube, the filter tube fixing seat, and the lower inner tube are interconnected.

3. A back-flushing filter drill rod for use in a coal mine, according to claim 1, wherein: The nozzle is positioned below the upper limit position of the cone valve core. When the cone valve core is at the lower limit position, the nozzle is between the cone valve core sealing rings and remains closed.

4. The back-flushing filter drill rod for underground coal mining of claim 1, wherein: The throttling block has a throttling channel in the middle. The cross-section of the throttling channel is smaller than the cross-section of the flow channel inside the upper outer pipe. When the fluid flows through the throttling channel, a throttling effect is formed, making the pressure at the upper end of the throttling block greater than the pressure at the lower end.

5. A method of using a back-flushing filter drill rod for use in a coal mine, the back-flushing filter drill rod being as claimed in any one of claims 1 to 4, the method comprising: Includes the following steps: A. During drilling, drilling fluid is supplied inside the drill pipe. The drilling fluid passes through a throttling block, which has a throttling channel inside. A throttling effect is formed at both ends of the throttling block, and a pressure difference is formed at both ends of the throttling block. The pressure at the upper end is greater than the pressure at the lower end. The fluid pressure at the upper end of the throttling block is P1, and the fluid pressure at the lower end of the throttling block is P2. Since P1 is greater than P2, the throttling block is subjected to a downward pressure difference force. The throttling block is set to remain stationary when the flow rate is less than the set value Q1, and to move downward when the flow rate is greater than Q1. B, Filter drill pipe reverse flushing: After the pump is started, the flow rate continues to increase until the rated flow rate. During the 0 to Q1 flow rate stage after the pump is started, the drilling fluid passes through the throttling block and forms a throttling effect at both ends of the throttling block, creating a pressure difference at both ends of the throttling block. The downward force of the pressure difference acting on the throttling block is insufficient to overcome the upward elastic force provided by the control spring. The throttling block and the cone valve core are in the upper limit position. The cone valve core blocks the channel between annulus C and annulus B. Since the pressure formed on the pressure valve core at flow rate Q1 is less than the elastic force of the unloading spring, the pressure valve core blocks the downward flow channel. The drilling fluid can only enter annulus B from annulus C through the annulus flow channel and the annulus A reverse flushing filter element, and finally be discharged to the external space through the nozzle. C. Normal drilling operation: When the flow rate is Q2, Q2 flow rate is greater than Q1, forming a pressure difference across the throttling block. The downward force of the pressure difference on the throttling block is sufficient to overcome the upward elastic force provided by the control spring. The throttling block and the cone valve core move downward, the annular flow channel is blocked by the throttling block, and the nozzle is blocked by the cone valve core. The fluid pressure rises rapidly, and the pressure on the pressure valve core overcomes the elastic force of the unloading spring. The pressure valve core moves downward, connecting annulus C and annulus B. The fluid enters annulus B from annulus C, passes through the filter core, enters annulus A, and finally enters the lower equipment from annulus A through the pressure valve core, thus achieving the filtration of drilling fluid.

6. The use of a back-flushing filter drill rod in a coal mine according to claim 5, wherein: The elastic force of the control spring arranged below the spool is equal to the pressure difference force formed at both ends of the throttle block by the flow rate Q1.

7. The method of using a back-flushing filter drill rod in a coal mine according to claim 5, wherein: The elastic force of the unloading spring is greater than the pressure formed on the spool by the flow rate Q1.

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