High-efficiency positive displacement motor

Abstract

The present invention relates to an efficient positive displacement motor drill. Through a sliding sleeve that can rotate and axially slide and a conical filter screen, combined with structures such as slag discharge holes and backwashing holes, efficient filtration of impurities in drilling fluid and automatic slag discharge are achieved. When the resistance of the filter screen exceeds the elastic force of the return spring, the device automatically moves downward to form a backwashing channel, using the drilling fluid to reverse-flush the filter screen and discharge the impurities through the slag discharge holes; after the slag discharge is completed, it quickly returns to the upper limit position under the action of the return spring. This structure effectively avoids clogging of the filter screen, extends the service life of the positive displacement motor, and can be dredged by removing the plug when the backwashing hole is clogged. Compared with traditional equipment, the structure of the present invention is compact, has a high filtration efficiency, and the rotation centrifugation and backwashing cooperate with each other, greatly improving the continuity of drilling operations, reducing maintenance costs, and being applicable to downhole environments with high sand content or high viscosity. This structure is convenient to maintain, and the backwashing hole can be quickly dredged by replacing or cleaning the plug, shortening the troubleshooting time.

Description

Technical Field

[0001] The high-efficiency positive displacement motor of the present invention relates particularly to a high-efficiency positive displacement motor applied in the technical field of drilling engineering. Background Art

[0002] With the increasingly in-depth development of the exploration of resources such as oil, natural gas, and geothermal energy, the downhole operation environment has become increasingly complex, posing higher requirements for the efficiency and durability of drilling equipment. As a commonly used downhole power tool, during operation, a positive displacement motor needs to ensure that the drilling fluid continuously flushes and lubricates the inside of the motor during the flow process. However, larger particulate matters such as sand and cuttings contained in the drilling fluid often cause wear or blockage to the internal structure of the motor, resulting in frequent shutdowns for maintenance and a decline in operation efficiency. Therefore, in order to reduce the damage of impurities to the positive displacement motor and improve its service life and working efficiency, various filtering devices have emerged.

[0003] The specification of Chinese invention patent CN116474443B discloses a filtering device for a positive displacement motor, belonging to the technical field of filtering devices. It includes a hollow tube with a fixedly connected filter screen inside, and a communication groove and a collection groove are arranged on the inner wall of the hollow tube. By using the inclined design of the filter screen from top to bottom in cooperation with a moving component, the filtration and collection of impurities in the drilling fluid are realized, which helps to improve the drilling efficiency.

[0004] The specification of Chinese invention patent CN110947222B discloses a filtering device for a positive displacement motor, its use method, and its installation method. This technology mainly opens an annular groove on the outer wall of the hollow tube, and a filter element, a diversion support, a nut, and a support sleeve are arranged inside. By using the diversion support to block and divert the mud first, the erosion of the filter element and the nut by the mud is reduced, and the service life of key components is prolonged.

[0005] The above two existing technologies have improved the filtration and protection ability of the drilling fluid to a certain extent by improving the internal structure of the hollow tube, adding a diversion support, and a moving component, etc. However, there are still the following limitations: the filter screen is prone to local blockage during long-term use, lacking an efficient automatic backwashing or centrifugal slag discharging mechanism, resulting in the need for frequent disassembly and cleaning. When the sand content or viscosity in the downhole environment is relatively high, impurities quickly accumulate on the surface of the filter screen, affecting the working efficiency of the positive displacement motor. Relying on a simple inclined or external flushing structure is difficult to continuously keep the filter screen unblocked. Some designs do not consider the discharge path of impurities around the filter screen sufficiently, easily causing secondary accumulation or cyclic blockage of impurities, and additional auxiliary tools or complex moving components are required for cleaning. Summary of the Invention

[0006] To solve the above problems, the present invention provides an efficient positive displacement motor drill, including a drill pipe. A positive displacement motor is provided on the lower side of the drill pipe. A filter section is fixedly connected between the drill pipe and the positive displacement motor. A sliding sleeve is slidably connected in the filter section. A fixing ring is fixedly connected in the sliding sleeve. A filter screen fixing ring is clamped at the top end of the fixing ring. A support is fixedly connected to the bottom end of the fixing ring. A rotating shaft is fixedly connected in the support. The top end of the rotating shaft penetrates the filter screen, and a top plate is threadedly connected to the penetrated part. A transmission sleeve is fixedly connected to the bottom end of the rotating shaft. A transmission shaft is slidably connected along its axial direction in the transmission sleeve through a spline. A bottom plate is fixedly connected to a position near the bottom end of the outer end of the transmission sleeve. A top ring, a bottom ring and a retaining ring are fixedly connected to the inner wall of the filter section. The bottom end of the transmission shaft is fixedly connected to the top end of the rotor of the positive displacement motor.

[0007] In the present invention, by providing a sliding sleeve and a conical filter screen in the filter section that can simultaneously achieve rotation and axial sliding, and combining structures such as slag discharge holes and backwashing holes, it is possible to continuously and efficiently filter the drilling fluid during actual drilling operations, timely discharge the intercepted larger particle impurities, and trigger the automatic backwashing function when necessary.

[0008] A plurality of first slag discharge holes are formed at a position between the top end of the sliding sleeve and the fixing ring. The plurality of first slag discharge holes are arranged in a circumferential array around the axis of the sliding sleeve. The filter screen is of a conical structure, and the end with a smaller diameter is arranged close to the top plate.

[0009] The outer diameters of the top plate and the bottom plate are larger than the inner diameters of the top ring and the bottom ring. When the top plate and the bottom plate move down to the lower limit position, the bottom ends of the top plate and the bottom plate respectively abut against the top ends of the top ring and the bottom ring.

[0010] A plurality of second slag discharge holes corresponding to the first slag discharge holes are formed on the filter section. When the top plate and the bottom plate move up to the upper limit position, the top end of the sliding sleeve abuts against the bottom end of the top ring. When the sliding sleeve moves down to the lower limit position, the first slag discharge holes are communicated with the second slag discharge holes.

[0011] A plurality of backwashing holes are formed on the filter section. Each backwashing hole is located between two second slag discharge holes. The top end and the bottom end of the second slag discharge holes are both communicated with the inner wall of the filter section.

[0012] Through grooves corresponding to the backwashing holes are formed at a position at the bottom end of the fixing ring on the sliding sleeve. When the sliding sleeve moves to the upper limit position, the bottom end of the through groove is located above the bottom end of the backwashing hole, and at this time, the sliding sleeve blocks the bottom end of the backwashing hole.

[0013] When the sliding sleeve moves to the lower limit position, the bottom end of the backwashing hole is communicated with the through groove. A return spring is fixedly connected between the bottom end of the bottom plate and the top end of the retaining ring.

[0014] The return spring is a conical spring, and the end with a smaller diameter is arranged close to the bottom plate.

[0015] The top and bottom ends of the backwashing holes penetrate through the filtering section, and the positions near the outer end of the filtering section are blocked by plugs, which are used to dredge and clean the backwashing holes and facilitate processing.

[0016] In summary, the present application has the following beneficial effects:

[0017] 1. Under the dual action of the rotational centrifugal force and the conical structure, the filter screen pushes impurities towards the inner wall of the sliding sleeve, avoiding the concentrated accumulation of impurities on the front surface of the filter screen. Thus, the risk of filter screen blockage is significantly reduced, the filter screen is not easily blocked by impurities, the wear on the screw motor is reduced, and the overall service life of the drill tool is significantly extended.

[0018] 2. When the sliding sleeve moves up and down, the first slag discharge hole and the second slag discharge hole can communicate at specific positions to form a slag discharge channel, and the impurities deposited between the filter screen and the sliding sleeve are discharged in a timely manner. By means of the power within the system, slag discharge is directly completed, shortening the downtime for manual cleaning or disassembly and improving the construction progress.

[0019] 3. When the resistance of the filter screen increases to exceed the elastic force of the return spring, the sliding sleeve drives the filter screen and related components to move downward, so that the through groove is connected to the bottom end of the backwashing hole, guiding the drilling fluid to reverse-scour the filter screen, automatically removing the impurities deposited on the surface and around the filter screen. This process effectively restores the filtering ability of the filter screen and avoids frequent disassembly and cleaning.

[0020] 4. After the filtering and slag discharge are completed, the return spring will push the sliding sleeve and the filter screen back to the initial position, closing the slag discharge hole and the backwashing hole again, and the drilling fluid resumes the normal filtering process. This automatic reset method not only ensures the continuity of work but also avoids the complex operations of manual intervention.

[0021] 5. Both ends of the backwashing hole penetrate through the filtering section and are blocked by plugs at the outer end. If blockage occurs, the plugs can be removed to conveniently dredge and clean, which greatly improves the maintenance efficiency and reduces the downtime for maintenance and repair and the maintenance cost.

[0022] 6. In the downhole operation environment with high viscosity or a large sand content, the filtering, slag discharge, and backwashing processes of the present invention can continuously and effectively operate, avoiding the problems of frequent replacement or downtime caused by sediment blockage, and providing stable support for long-term continuous drilling operations. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is the usage state of the present application Figure 1 ;

[0024] Figure 2 is the partial explosion view of the present application;

[0025] Figure 3 is the overall explosion view of the present application;

[0026] Figure 4 Front view of the present application;

[0027] Figure 5 of the present application Figure 4 A - A cross - sectional view in;

[0028] Figure 6 of the present application Figure 5 B - B cross - sectional view in;

[0029] Figure 7 of the present application Figure 6 C - C cross - sectional view in;

[0030] Figure 8 of the present application Figure 7 D - D cross - sectional view in;

[0031] Figure 9 of the present application Figure 7 E - E cross - sectional view in;

[0032] Figure 10 Use state of the present application Figure 2 ;

[0033] Figure 11 Appearance structure diagram of the present application.

[0034] Explanation of reference numerals in the figure:

[0035] 1. Drill pipe; 2. Screw motor; 3. Filter section; 4. Sliding sleeve; 5. Fixed ring; 6. Filter screen; 7. Bracket; 8. Rotating shaft; 9. Top plate; 10. Transmission sleeve; 11. Transmission shaft; 12. Bottom plate; 13. Top ring; 14. Bottom ring; 15. Retaining ring; 16. Discharge slag hole one; 17. Discharge slag hole two; 18. Backwashing hole; 19. Through groove; 20. Return spring. Specific embodiments

[0036] The following will explain the three embodiments of the present application in detail with reference to the accompanying drawings. Embodiment

[0037] This embodiment aims to solve the problem of wear on the screw motor 2 caused by impurities in the drilling fluid. By installing a rotatable and slidable filter screen 6 inside the filter section 3 and cooperating with the structure of the discharge slag hole one 16 and the discharge slag hole two 17, the functions of efficient filtration and slag discharge are achieved.

[0038] In Embodiment 1, the high - efficiency screw drill of the present invention includes a drill pipe 1. A screw motor 2 is fixedly installed on the lower side of the drill pipe 1. A filter section 3 is fixedly connected between the drill pipe 1 and the screw motor 2 by welding, flange connection or other means. The inner wall of the filter section 3 is fixedly connected with a top ring 13, a bottom ring 14 and a retaining ring 15 to form a limit support for other internal components.

[0039] Inside the filtration section 3, a sliding sleeve 4 is slidably connected. The structure of the sliding sleeve 4 is cylindrical. A fixing ring 5 is fixedly connected to its inner side. A filter screen 6 is snap-connected to the top end of the fixing ring 5. The bottom end of the fixing ring 5 is fixedly connected to a support 7. A rotating shaft 8 is fixedly connected inside the support 7. The top end of the rotating shaft 8 passes through the filter screen 6 and is connected to the top plate 9 in a threaded manner. The bottom end of the rotating shaft 8 is fixedly connected to a transmission sleeve 10. The transmission sleeve 10 is axially slidably connected to a transmission shaft 11 through splines inside, ensuring that the transmission shaft 11 can synchronously transfer the power of the screw motor 2 to components such as the transmission sleeve 10 and the sliding sleeve 4. A bottom plate 12 is fixedly installed at a position near the bottom end of the outer side of the transmission sleeve 10. The bottom plate 12 is similar to the top plate 9 in structure, and its outer diameter is larger than the inner diameter of the bottom ring 14.

[0040] Between the top of the fixing ring 5 and the sliding sleeve 4, the sliding sleeve 4 is provided with a plurality of first slag discharge holes 16. These first slag discharge holes 16 are evenly distributed in a circle around the axis of the sliding sleeve 4. Correspondingly, the wall of the filtration section 3 is also provided with second slag discharge holes 17 corresponding to the first slag discharge holes 16 one by one. When the sliding sleeve 4 is at the lower limit position, the first slag discharge holes 16 are exactly connected to the second slag discharge holes 17, and the impurities retained inside the sliding sleeve 4 can be discharged. The filter screen 6 adopts a conical structure, and the end with a smaller diameter is arranged close to the top plate 9. This conical arrangement helps to gradually push the larger particle impurities to the periphery of the filter screen 6 during the flow and rotation of the drilling fluid, further reducing the possibility of blockage of the filter screen 6.

[0041] The outer diameters of the top plate 9 and the bottom plate 12 are designed to be larger than the inner diameters of the top ring 13 and the bottom ring 14. When the sliding sleeve 4 is forced to move downward to the lower limit position, the top plate 9 will abut against the top end of the top ring 13, and the bottom plate 12 will abut against the top end of the bottom ring 14, thereby restricting the sliding sleeve 4 from continuing to move downward. On the contrary, when the sliding sleeve 4 moves upward to the upper limit position, the top end of the sliding sleeve 4 will abut against the bottom end of the top ring 13. At this time, the first slag discharge holes 16 and the second slag discharge holes 17 are in a misaligned state, preventing the continuous opening of the slag discharge holes and causing ineffective loss.

[0042] Working process

[0043] During the drilling operation, the drilling fluid flows from the drill pipe 1 to the screw motor 2 and enters the inside of the filtration section 3. When the larger particle impurities pass through the filter screen 6, they are effectively intercepted by the filter screen 6 and retained in the space between the sliding sleeve 4 and the filter screen 6. The drilling fluid continues to flow into the screw motor 2 after passing through the filter screen 6 to drive the rotor of the screw motor 2 to rotate.

[0044] The rotation of the rotor of the screw motor 2 drives the drive shaft 11 to rotate. The drive shaft 11 is connected to the transmission sleeve 10 through splines, and synchronously drives components such as the sliding sleeve 4, the fixed ring 5, the filter screen 6, the bracket 7, the rotating shaft 8, the top plate 9, and the bottom plate 12 to rotate together. Since the filter screen 6 is conical and generates centrifugal force during rotation, impurities can be pushed along the surface of the filter screen 6 towards the inner wall of the sliding sleeve 4. With the combined effects of the self-flow scouring of the drilling fluid and centrifugal force, the filter screen 6 is not prone to centralized blockage, thereby improving the filtration efficiency and reducing the cleaning workload.

[0045] When impurities in the filtration section 3 continuously accumulate around the filter screen 6 or within the sliding sleeve 4 and reach a certain degree, the sliding sleeve 4 may move up and down to a certain extent under the action of the drilling fluid pressure or operating force. When the sliding sleeve 4 moves down to the lower limit position, the first slag discharge hole 16 aligns with the second slag discharge hole 17, thereby providing a discharge channel for the internally deposited impurities. As a result, the impurities between the sliding sleeve 4 and the filter screen 6 can be partially discharged outside the filtration section 3 along with the drilling fluid. This process can effectively prevent impurities from accumulating inside for a long time, further improving the service life and working efficiency of the screw motor 2.

[0046] By arranging a rotatable and slidable sliding sleeve 4 in the filtration section 3 and installing a conical filter screen 6 inside the sliding sleeve 4, larger particle impurities can be intercepted and pushed away from the surface of the filter screen 6 under the scouring and rotational centrifugal action of the drilling fluid, reducing the clogging probability of the filter screen 6 and extending the service life of the filter screen 6.

[0047] The conical structure of the filter screen 6 can concentrate impurities along the surface of the filter screen 6 towards the inner wall of the sliding sleeve 4 under the action of centrifugal force, thereby improving the filtration efficiency and saving cleaning time.

[0048] The relative misalignment and alignment between the first slag discharge hole 16 and the second slag discharge hole 17 can achieve the slag discharge function through the up and down movement of the sliding sleeve 4 when the filter screen 6 is severely clogged, thereby keeping the inside of the filter screen 6 and the sliding sleeve 4 unobstructed.

[0049] The outer diameters of the top plate 9 and the bottom plate 12 are designed to be larger than the inner diameters of the top ring 13 and the bottom ring 14, which can achieve precise control of the up and down limits of the sliding sleeve 4, avoid structural damage caused by excessive movement, and at the same time provide conditions for the communication between the first slag discharge hole 16 and the second slag discharge hole 17 when necessary.

[0050] Through the combined use of the above structures, the screw motor 2 is protected by the filter screen 6 to reduce wear, reduce the frequency of shutdown for maintenance, and thus improve the construction efficiency of the entire screw drill.

[0051] In summary, in Embodiment 1, by arranging a sliding sleeve 4, a fixing ring 5 and a conical filter screen 6 inside the filtering section 3, and respectively arranging a first slag discharge hole 16 and a second slag discharge hole 17 on the wall of the sliding sleeve 4 and the filtering section 3, the continuous and efficient filtration of the drilling fluid is achieved by skillfully utilizing the rotational centrifugation and the up-and-down limit cooperation of the movable sliding sleeve 4, significantly reducing the wear of the screw motor 2 caused by solid impurities, prolonging its service life and improving the overall operation efficiency. This embodiment has the advantages of simple structure, convenient use and high filtration efficiency, and is applicable to various drilling occasions where it is necessary to protect the screw motor 2 from large particle impurities. Embodiment

[0052] On the premise of retaining the basic structure and the filtering and slag discharging functions of the high-efficiency screw drill in Embodiment 1, this embodiment adds components such as a backwashing hole 18, a through groove 19 and a return spring 20, making the cleaning and maintenance of the filter screen 6 more rapid and efficient, and greatly improving the continuity and reliability of the drilling operation.

[0053] On the upper part or the outer wall of the filtering section 3, a plurality of backwashing holes 18 are opened. Each backwashing hole 18 is located between two second slag discharge holes 17 and is communicated with the inner wall of the filtering section 3. For the convenience of cleaning during subsequent blockage and daily maintenance, the top and bottom ends of the backwashing hole 18 penetrate through the filtering section 3 and are blocked by a plug at a position close to the outer end of the filtering section 3. In this way, if the backwashing hole 18 is blocked by mud or sand and gravel, the plug can be directly removed to quickly dredge and clean the backwashing hole 18. In addition, since the backwashing hole 18 is communicated with the outer end of the filtering section 3, it is also convenient for rapid drilling and accurate positioning during processing.

[0054] Corresponding to the backwashing hole 18, through grooves 19 with the same number and corresponding positions are opened on the outer surface of the sliding sleeve 4 (near the bottom end of the fixing ring 5). The through grooves 19 and the backwashing holes 18 can be aligned or misaligned during the up-and-down movement of the sliding sleeve 4. Specifically, when the sliding sleeve 4 moves to the upper limit position, the bottom end of the through groove 19 is located above the bottom end of the backwashing hole 18, thereby blocking the bottom end of the backwashing hole 18, and no drilling fluid will flow into the inside of the sliding sleeve 4 through the backwashing hole 18. On the contrary, when the sliding sleeve 4 moves to the lower limit position, the through groove 19 is communicated with the bottom end of the backwashing hole 18, providing a channel for the backwashing operation of the filter screen 6.

[0055] Between the bottom end of the bottom plate 12 and the top end of the retaining ring 15, a return spring 20 is also fixedly connected. The return spring 20 is preferably a conical spring, and the end with a smaller diameter is installed near the bottom plate 12. This structure can not only provide sufficient elastic force to balance the drilling fluid pressure when the filter screen 6 drives the sliding sleeve 4 to move downward, but also timely reset the sliding sleeve 4 and the filter screen 6 to the upper limit position after slag discharge and backwashing, so that the entire filter slag discharge device can re-enter the normal filtering working state.

[0056] Except for the above newly added or improved components, the high-efficiency positive displacement motor of Embodiment 2 retains all the basic structures in Embodiment 1, including the drill pipe 1, the positive displacement motor 2, the filtering section 3, the sliding sleeve 4, the fixed ring 5, the filter screen 6, the support 7, the rotating shaft 8, the top plate 9, the transmission sleeve 10, the transmission shaft 11, the bottom plate 12, the top ring 13, the bottom ring 14, and the retaining ring 15, etc. Their connection methods, positional relationships, and basic functions during drilling are the same as those in Embodiment 1, and will not be elaborated here.

[0057] Working process

[0058] When the high-efficiency positive displacement motor is working normally, the drilling fluid enters the filtering section 3 through the positive displacement motor 2 and then flows to the positive displacement motor 2 to drive the rotation of the rotor of the positive displacement motor 2. During this process, the filter screen 6 intercepts larger particle impurities in the drilling fluid to prevent these particles from entering the inside of the positive displacement motor 2 and causing wear. The sliding sleeve 4, the fixed ring 5, and the filter screen 6 rotate together with the rotation of the transmission shaft 11. With the conical structure and centrifugal force of the filter screen 6, the impurities are pushed towards the inner wall of the sliding sleeve 4 and cooperate with the first slag discharge hole 16 and the second slag discharge hole 17 to discharge slag when necessary.

[0059] As the impurities around the filter screen 6 continue to accumulate, the flow area of the filter screen 6 will gradually decrease and the flow resistance will increase. When the resistance borne by the filter screen 6 exceeds the elastic force of the return spring 20, under the action of the drilling fluid pressure, the filter screen 6 drives the sliding sleeve 4, the fixed ring 5, the support 7, the rotating shaft 8, the top plate 9, the transmission sleeve 10, and the bottom plate 12 to move downward together until the top plate 9 abuts against the top ring 13 and the bottom plate 12 abuts against the bottom ring 14, forming a lower limit position.

[0060] At this time, the top plate 9 and the bottom plate 12 jointly block part of the drilling fluid from continuing to enter the filtering section 3, and the first slag discharge hole 16 and the second slag discharge hole 17 are aligned and connected. More importantly, due to the downward movement of the sliding sleeve 4, the through groove 19 is connected to the bottom end of the backwashing hole 18, and the drilling fluid can flow from the positive displacement motor 2 through other channels or the external return port into the backwashing hole 18, and then enter the inside of the sliding sleeve 4 to perform a bottom-up backwashing on the filter screen 6.

[0061] During the backwashing process, the drilling fluid will flow from the bottom end of the filter screen 6 to the top end of the filter screen 6, and at the same time, a large amount of impurities accumulated around the filter screen 6 will be flushed out through the slag discharge hole 16 and the slag discharge hole 17. This "reverse flushing" effectively removes the sediment on the surface of the filter screen 6, preventing shutdown for maintenance due to the decline in filtration effect.

[0062] When a certain amount of drilling fluid completes the backwashing, the impurities are discharged outside the filtration section 3, and the pressure between the sliding sleeve 4 and the periphery of the filter screen 6 gradually tends to balance. Consequently, the pressure difference between the top plate 9 and the bottom plate 12 decreases. At this time, the return spring 20 releases elastic force, causing the sliding sleeve 4, the fixed ring 5, the filter screen 6, the support 7, the rotating shaft 8, the top plate 9, the transmission sleeve 10, and the bottom plate 12 to move upward from the lower limit position until they return to the upper limit position. At this time, the slag discharge hole 16 and the slag discharge hole 17 are staggered, and the through groove 19 and the bottom end of the backwashing hole 18 are also staggered. The backwashing hole 18 is blocked again, and the drilling fluid resumes the normal filtration process.

[0063] If it is found that the backwashing hole 18 itself is blocked during use, it is only necessary to remove the plug at the outer end of the backwashing hole 18 to carry out dredging and cleaning, which greatly facilitates the maintenance operation and improves the operation efficiency.

[0064] During use, the drilling fluid enters the filtration section 3 through the screw motor 2, and then enters the screw motor 2 from the filtration section 3 to drive the screw motor 2 to rotate;

[0065] During this process, the substances with larger particles in the drilling fluid are intercepted and filtered by the filter screen 6;

[0066] During this process, the rotor on the screw motor 2 drives the transmission shaft 11 to rotate. The transmission shaft 11 then drives the sliding sleeve 4, the fixed ring 5, the filter screen 6, the support 7, the rotating shaft 8, the top plate 9, the transmission sleeve 10, and the bottom plate 12 to rotate together. During the rotation of the sliding sleeve 4 and the filter screen 6, under the action of centrifugal force, the filtered impurities are pushed towards the inner wall of the sliding sleeve 4, making it difficult for the impurities to block the filter screen 6. At the same time, the conical structure of the filter screen 6 causes the impurities to move towards the direction close to the inner wall of the sliding sleeve 4 under the push of the drilling fluid. The dual effects of centrifugation and the conical structure make it difficult for the impurities to block the filter screen 6;

[0067] During the use process, as impurities gradually accumulate between the sliding sleeve 4 and the filter screen 6, the effective flow area of the filter screen 6 decreases, resulting in an increase in the resistance of the filter screen 6. When the resistance of the filter screen 6 increases to exceed the elastic force of the return spring 20, under the pressure of the drilling fluid, the filter screen 6 drives the sliding sleeve 4, the fixed ring 5, the bracket 7, the rotating shaft 8, the top plate 9, the transmission sleeve 10, and the bottom plate 12 to move downward together until the top plate 9 and the bottom plate 12 respectively abut against the top ends of the top ring 13 and the bottom ring 14 to reach the lower limit position. At this time, the drilling fluid in the screw motor 2 is blocked by the top plate 9 and cannot enter the filtering section 3. At the same time, the first slag discharge hole 16 is communicated with the second slag discharge hole 17, and the through groove 19 is communicated with the bottom end of the backwashing hole 18. At this time, the drilling fluid flows into the sliding sleeve 4 through the backwashing hole 18, and then the drilling fluid flows from the bottom end of the filter screen 6 to the top end of the filter screen 6 and then is discharged from the first slag discharge hole 16 and the second slag discharge hole 17. During this process, the drilling fluid performs backwashing on the filter screen 6, and at the same time flushes out the impurities accumulated between the sliding sleeve 4 and the filter screen 6 from the first slag discharge hole 16 and the second slag discharge hole 17;

[0068] With the backwashing, a large amount of drilling fluid flows into the space between the top plate 9 and the bottom plate 12, gradually reducing the pressure difference at both ends of the top plate 9. Under the elastic force of the return spring 20, the sliding sleeve 4, the fixed ring 5, the filter screen 6, the bracket 7, the rotating shaft 8, the top plate 9, the transmission sleeve 10, and the bottom plate 12 move upward together until they reach the upper limit position;

[0069] After the sliding sleeve 4 reaches the upper limit position, the first slag discharge hole 16 is staggered from the second slag discharge hole 17 to block the first slag discharge hole 16. At the same time, the through groove 19 is staggered from the bottom end of the backwashing hole 18 to block the bottom end of the backwashing hole 18, and the drilling fluid no longer passes through the backwashing hole 18. In this way, a process of filtration, slag discharge, backwashing, and resetting is completed. This process continuously cycles to filter the impurities in the drilling fluid, prevent the wear of the screw motor 2 by particles, reduce the time for shutdown, replacement, and maintenance, etc., and thus improve the efficiency of the positive displacement motor;

[0070] During the use process, if the backwashing hole 18 is blocked, the plug on the backwashing hole 18 can be removed to dredge and clean the backwashing hole 18. At the same time, the backwashing hole 18 is communicated with the outer end of the filtering section 3, which also facilitates the rapid machining of the backwashing hole 18 during processing.

[0071] On the basis of Embodiment 1, the backwashing hole 18 and the through groove 19 are added. In cooperation with the first slag discharge hole 16 and the second slag discharge hole 17, the filter screen 6 can be backwashed by means of the drilling fluid when it bears a large resistance, effectively removing the impurities attached between the filter screen 6 and the sliding sleeve 4, and greatly reducing the risk of blockage.

[0072] By setting the return spring 20, after the backwashing process is completed, the sliding sleeve 4 can automatically move upward to the initial working position, which not only maintains the stability of the overall structure but also avoids repeated manual adjustment, improving the filtration efficiency and the continuity of drilling operations.

[0073] The up-and-down through design of the backwashing hole 18 and its plugging at the outer end of the filtration section 3 make it easy to disassemble, clean, and dredge after use or during use, effectively extending the service life of the high-efficiency positive displacement motor and reducing the downtime caused by blockage.

[0074] Compared with the conventional design that only relies on the rotational centrifugal effect of a single filter screen 6, this embodiment combines backwashing and the return spring 20, greatly improving the cleaning efficiency and durability of the filter screen 6, avoiding frequent disassembly and cleaning, and reducing the maintenance cost.

[0075] Overall, based on Embodiment 1, Embodiment 2 realizes a dynamic cycle of "filtration - slag discharge - backwashing - reset", greatly reducing the wear of the positive displacement motor 2, improving the drilling operation efficiency and economic benefits, and is suitable for drilling occasions that require long-term continuous operation and have high requirements for filtration quality.

[0076] In summary, by adding structures such as the backwashing hole 18, the through groove 19, and the return spring 20, Embodiment 2 enables the high-efficiency positive displacement motor to still maintain excellent filtration and slag discharge performance in deep wells, high-viscosity, or high-sand-content working environments, and at the same time has the function of rapid backwashing, greatly improving the impurity treatment efficiency and the protection effect of the positive displacement motor 2. Compared with Embodiment 1, the technical solution of this embodiment is more perfect and has a wider application range, which is of great significance for extending the overall life of the positive displacement motor.

[0077] Combined with the current actual needs, the above implementation methods adopted in this application do not limit the protection scope thereto. Within the scope of knowledge of those skilled in the art, various changes made without departing from the concept of this application still fall within the protection scope of the present invention.

Claims

1. High-efficiency positive displacement motor, characterized in that: It includes a drill pipe (1). A positive displacement motor (2) is provided on the lower side of the drill pipe (1). A filter section (3) is fixedly connected between the drill pipe (1) and the positive displacement motor (2). A sliding sleeve (4) is slidably connected in the filter section (3). A fixing ring (5) is fixedly connected in the sliding sleeve (4). A filter screen (6) is snap-connected to the top end of the fixing ring (5). A support (7) is fixedly connected to the bottom end of the fixing ring (5). A rotating shaft (8) is fixedly connected in the support (7). The top end of the rotating shaft (8) penetrates through the filter screen (6), and a top plate (9) is threadedly connected to the penetrated part. The bottom end of the rotating shaft (8) is fixedly connected to a transmission sleeve (10). A transmission shaft (11) is slidably connected in the transmission sleeve (10) along its axial direction through splines. A bottom plate (12) is fixedly connected to the outer end of the transmission sleeve (10) near its bottom end. A top ring (13), a bottom ring (14) and a retaining ring (15) are fixedly connected to the inner wall of the filter section (3). The bottom end of the transmission shaft (11) is fixedly connected to the top end of the rotor of the positive displacement motor (2). A plurality of slag discharge holes one (16) are formed in the sliding sleeve (4) at the position between its top end and the fixing ring (5). The plurality of slag discharge holes one (16) are distributed in a circumferential array around the axis of the sliding sleeve (4). The filter screen (6) is of a conical structure, and the end with a smaller diameter is arranged close to the top plate (9). The outer diameters of the top plate (9) and the bottom plate (12) are larger than the inner diameters of the top ring (13) and the bottom ring (14). When the top plate (9) and the bottom plate (12) move down to the lower limit position, the bottom ends of the top plate (9) and the bottom plate (12) respectively abut against the top ends of the top ring (13) and the bottom ring (14). A plurality of slag discharge holes two (17) corresponding to the slag discharge holes one (16) one by one are formed in the filter section (3). When the top plate (9) and the bottom plate (12) move up to the upper limit position, the top end of the sliding sleeve (4) abuts against the bottom end of the top ring (13). When the sliding sleeve (4) moves down to the lower limit position, the slag discharge holes one (16) are communicated with the slag discharge holes two (17). A plurality of backwashing holes (18) are formed in the filter section (3). Each backwashing hole (18) is located between two slag discharge holes two (17). The top end and the bottom end of the slag discharge hole two (17) are both communicated with the inner wall of the filter section (3). A through groove (19) corresponding to the backwashing hole (18) one by one is formed in the sliding sleeve (4) at the position corresponding to the backwashing hole (18) at the bottom end of the fixing ring (5). When the sliding sleeve (4) moves to the upper limit position, the bottom end of the through groove (19) is located above the bottom end of the backwashing hole (18). At this time, the sliding sleeve (4) blocks the bottom end of the backwashing hole (18). When the sliding sleeve (4) moves to the lower limit position, the bottom end of the backwashing hole (18) is communicated with the through groove (19). A return spring (20) is fixedly connected between the bottom end of the bottom plate (12) and the top end of the retaining ring (15).

2. The high-efficiency positive displacement motor according to claim 1, wherein: The return spring (20) is a conical spring, and the end with a smaller diameter is arranged close to the bottom plate (12).

3. The high-efficiency positive displacement motor according to claim 1, characterized in that: The top and bottom ends of the backwashing holes (18) penetrate through the filtering section (3), and the positions near the outer end of the filtering section (3) are blocked by plugs, which are used to dredge and clean the backwashing holes (18) and facilitate processing.

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