Air screw drill fly-off prevention one-way valve

Abstract

The application discloses an air screw drill anti-flying one-way valve, which comprises a valve body and a valve core, a plurality of P-shaped structure annular bends are symmetrically arranged on the valve core and sequentially arranged along the axial direction, the direction characteristics of the P-shaped structure annular bends are utilized to control the flow direction of the gas passing through the valve core, unlike the conventional one-way valve, no movement mechanism is arranged, and no complex structure or movement is needed to control the gas, the one-way conduction of the gas can be realized without input energy, the valve is installed between an air screw motor and a drill string, the valve core blocks the upward return of the gas above the air screw motor, a part of the gas can be reserved in the third chamber, therefore, a certain pressure is maintained above the air screw motor, the flying problem of the air screw, i.e., the sudden increase of the air screw volume and the sudden increase of the motor rotating speed caused by the pressure reduction due to the tripping of the air screw, can be effectively avoided.

Description

Technical Field

[0001] This invention relates to the field of air screw control technology. More specifically, this invention relates to a one-way valve for preventing runaway of air screw drill bits. Background Technology

[0002] Air drilling technology is a gas-based fluid underbalanced drilling technology that uses air as the circulating medium. Due to its significant advantages in reservoir protection and increasing mechanical drilling speed, it is widely used both domestically and internationally. Air screw drills are essential tools for drilling directional wells and various special process wells using gas drilling or underbalanced drilling techniques. Their structure and performance directly affect the efficiency of gas drilling operations. Although air screw drills have significant advantages in increasing mechanical drilling speed, reducing drilling cycles, and lowering drilling costs, some problems also exist during their application, with the "runaway" problem being the most serious.

[0003] The "runaway" problem refers to the phenomenon where, due to the compressibility of air, the motor pressure differential decreases significantly during tripping, leading to a reduction in air pressure at the motor inlet, an increase in air volume, and a sudden increase in motor speed. This runaway problem causes the motor to generate a large amount of heat in a short period, affecting the lifespan of the motor stator rubber. It also increases the operating frequency of the universal joints, drive shaft bearings, and motor stator and rotor within the air screw drill bit, accelerating wear, shortening lifespan, and severely impacting drilling efficiency and costs. Therefore, solving the "runaway" problem is crucial for extending the lifespan of air screw drill bits. However, current solutions often involve complex structural systems to overcome insufficient air pressure at the motor inlet, resulting in complex implementation processes and excessively high costs. Summary of the Invention

[0004] One object of the present invention is to solve at least the above-mentioned problems and to provide at least the advantages that will be described later.

[0005] Another objective of this invention is to provide a one-way valve for preventing runaway in air screw drills, in order to solve the technical problems of complex structural design and high cost in the prior art for dealing with runaway issues in air screw drills.

[0006] To achieve these objectives and other advantages according to the present invention, an anti-runaway check valve for air screw drill bits is provided, comprising:

[0007] The valve body has a male thread at one end that is threaded to the anti-drop assembly. The valve body has a through hole along the axial direction. The through hole is divided into a first chamber, a second chamber, and a third chamber with decreasing diameters at the end facing the male thread. The first chamber has a female thread that is threaded to the drill string. The second chamber has a cylindrical structure. The third chamber serves as an air storage chamber.

[0008] The valve core is installed in the second chamber and is configured to fit the shape of the second chamber. The valve core can rotate circumferentially relative to the second chamber. The valve core has a flow channel along the axial direction. The flow channel includes multiple annular bends with a P-shaped structure arranged sequentially along the axial direction. The annular bend has an inlet section on the side facing the female thread and an outlet section on the side facing the male thread. The inlet section and the outlet section are respectively inclined relative to the valve core axis and symmetrical along the axial direction. The inlet section is positioned facing the outlet section. The outlet section of the previous annular bend and the inlet section of the next annular bend are connected in the same direction. The outlet section and the inlet section at both ends of the flow channel respectively penetrate the corresponding ends of the valve core to form working ports. One working port is connected to the drill string and the other working port is connected to the third chamber.

[0009] The adjusting sleeve is placed between the valve core and the drill string to fix the valve core and the drill string on the valve body axially.

[0010] Preferably, each of the annular bends is composed of a P-shaped structure consisting of an arc segment and a straight segment connected together. One end of the arc segment and the straight segment are smoothly connected to form a rounded corner, and the other end of the arc segment and the straight segment form an acute angle at the connection. The inlet segment extends from the end of the straight segment that has an acute angle with the arc segment, and the outlet segment is located at the rounded corner and is aligned with the tangent direction of the corresponding end of the arc segment.

[0011] Preferably, the diameter of the straight segment is larger than the diameter of the arc segment.

[0012] Preferably, the valve core includes valve core A and valve core B, which are semi-cylindrical structures with the same overall shape and size. Half of the flow channel is located on valve core A and the other half is located on valve core B, and the shapes arranged on valve core A and valve core B are completely consistent. Welding grooves are respectively provided on two edges of valve core A and valve core B. By welding the welding grooves opposite to those of valve core A and valve core B, valve core A and valve core B are connected as one unit to form the valve core.

[0013] Preferably, valve core A and valve core B are symmetrically provided with two pairs of keyholes at the end facing the female thread, and a flat key is inserted and fitted into each pair of keyholes. The end of the flat key near the female thread abuts against the corresponding surface of the adjusting sleeve.

[0014] Preferably, the length of the valve core is proportional to the number of stages of the annular bend, where the number of stages represents the number of annular bends arranged axially.

[0015] Preferably, the reverse control effect ratio of each stage of the annular bend is η, where the reverse control effect is the proportion of gas consumed when gas enters from the outlet section, first splits and then merges through the arc section and the straight section, and then flows out from the inlet section. The number of stages N that the annular bend needs to be designed for a given maximum displacement is calculated according to the following formula:

[0016]

[0017] Rounding the data obtained on the right up gives the value of the series N.

[0018] The present invention has at least the following beneficial effects:

[0019] (1) The air screw drill anti-runaway one-way valve of the present invention mainly includes a valve body and a valve core. The valve core is provided with multiple P-shaped annular bends that are symmetrical and arranged sequentially along the axial direction. By utilizing the directional characteristics of the annular bends, the flow direction of the gas passing through the valve core can be controlled. Unlike conventional one-way valves, no moving mechanism is provided. It does not require a complex structure or movement to control the gas. It can achieve one-way gas flow without input energy.

[0020] (2) When the air screw drill bit anti-runaway one-way valve of the present invention is set, the gas pressure in the upper part of the drill string is low during the start-up of the drill bit. Since the air screw drill bit anti-runaway one-way valve blocks the gas from returning to the upper part of the air screw motor through the valve core, the gas in the lower part of the air screw cannot flow smoothly into the upper part of the drill string. A part of the gas is retained in the third chamber. Therefore, a certain pressure will be maintained above the air screw motor, which can effectively avoid the runaway problem caused by the sudden decrease in pressure of the air screw during the start-up of the drill bit, which leads to the increase in the air volume in the air screw and the sudden increase in the motor speed.

[0021] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the air screw drill anti-runaway one-way valve of the present invention when the gas is flowing in the forward direction;

[0023] Figure 2 This is a schematic diagram of the anti-runaway check valve for air screw drills of the present invention when the gas flows in reverse.

[0024] Figure 3 This is a schematic diagram of the working position of the anti-runaway check valve for the air screw drill bit of the present invention;

[0025] The following are the reference numerals in the instruction manual's attached drawings: 1. Valve body; 2. Valve core; 3. Flat key; 4. Adjusting sleeve; 5. Sealing ring; 6. Anti-drop assembly; 7. Motor assembly; 8. Universal shaft assembly; 9. Drive shaft assembly; 10. First chamber; 11. Second chamber; 12. Third chamber; 13. Male thread; 14. Female thread; 15. Working port; 16. Annular bend; 17. Straight section; 18. Arc section. Detailed Implementation

[0026] The present invention will now be described in further detail with reference to the accompanying drawings, so that those skilled in the art can implement it based on the description.

[0027] It should be noted that, unless otherwise specified, the experimental methods described in the following embodiments are all conventional methods, and the reagents and materials described are all commercially available unless otherwise specified. In the description of this invention, the terms "lateral", "longitudinal", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0028] like Figure 1-3 As shown, the present invention provides a one-way valve for preventing runaway of air screw drill bits, comprising:

[0029] The valve body 1 has a male thread 13 at one end, which is threaded to the anti-drop assembly 6. The valve body 1 has a through hole along the axial direction. The through hole is divided into a first chamber 10, a second chamber 11, and a third chamber 12 with successively decreasing diameters at the end facing the male thread 13. The first chamber 10 has a female thread 14, which is threaded to the drill string. The second chamber 11 has a cylindrical structure. The third chamber 12 serves as an air storage chamber.

[0030] The valve core 2 is installed in the second chamber 11 and is configured to fit the shape of the second chamber 11. The valve core 2 can rotate circumferentially relative to the second chamber 11. The valve core 2 has a flow channel along the axial direction. The flow channel includes a plurality of annular bends 16 arranged in a P-shape along the axial direction. The annular bend 16 has an inlet section on the side facing the female thread 14 and an outlet section on the side facing the male thread 13. The inlet section and the outlet section are respectively inclined relative to the valve core 2 and symmetrical along the axial direction. The inlet section is positioned facing the outlet section. The outlet section of the previous annular bend 16 and the inlet section of the next annular bend 16 are connected in the same direction. The outlet section and the inlet section at both ends of the flow channel respectively penetrate the corresponding ends of the valve core 2 to form working ports 15. One working port 15 is connected to the drill string and the other working port 15 is connected to the third chamber 12.

[0031] Adjusting sleeve 4, which abuts between valve core 2 and drill string, is used to fix valve core 2 and drill string on valve body 1 along the axial direction.

[0032] For ease of explanation, Figure 1 , Figure 2 left side and Figure 3 The lower end is on the same side and connected to the anti-fall assembly 6. Figure 1 right side Figure 3 The upper end is on the same side and connected to the drill string, so that... Figure 3 The valve core 2 is inserted into the second chamber 11 from the end with the female thread 14 and is axially limited by the stepped surface. The valve core 2 can rotate circumferentially relative to the valve body 1. The other end of the valve core 2 abuts against the drill string through the adjusting sleeve 4. The relative position of the drill string and the valve core 2 is adjusted through the adjusting sleeve 4 to ensure that the valve core 2 and the drill string are fixed in the axial direction. The air screw drill anti-runaway one-way valve is connected to the anti-drop assembly 6, motor assembly 7, universal joint assembly 8 and drive shaft assembly 9 in sequence through the self-locking tapered male thread 13. A sealing ring is provided between the valve body and the anti-drop assembly for sealing connection. The diversion is the process of a section of fluid becoming multiple sections of fluid.

[0033] The flow rate and direction of the air fluid are controlled by the valve core 2. The flow channel on the valve core 2 does not have any moving mechanism, so the fluid can form a pressure drop characteristic with direction-related characteristics outside the working ports 15 on both sides of the valve core 2, forming the effect of a "fluid diode". That is, the flow resistance in one direction of gas flow is higher than that in the other direction, while the unidirectional flow of gas can be achieved without inputting energy in the positive direction, that is, from top to bottom.

[0034] Specifically, in combination Figure 1As shown, the gas flows from right to left in a forward direction, entering through an inlet section (working port 15) near the female thread 14. The inlet and outlet sections are axially inclined relative to each other, controlling the overall flow direction towards the third chamber 12. Due to the shape of the P-shaped annular bend 16, the gas is split. Most of the gas flows towards the outlet section along the extension direction of the inlet section, while a small portion flows with the annular bend 16. The gas flowing towards the outlet section reaches the outlet section. With the inlet and outlet sections symmetrical and inclined relative to the valve core 2, the gas collides with the sidewall of the outlet section. Furthermore, since the outlet section of the current annular bend 16 and the inlet section of the next annular bend 16 are along the same direction... Since the direction is connected and connected, most of the gas leaves the current annular bend 16 along the outlet section, while a small portion of the gas continues to flow along the annular bend 16. When subsequent gas enters the current annular bend 16, it undergoes the same diversion process and merges with the diverted gas at the corresponding position. At the same time, the small portion of gas that was diverted and flows around the annular bend 16 undergoes the next diversion. Gases flowing in the same direction as the majority of the gas retain more power, while gases flowing in the opposite direction gradually lose power in the opposite direction until they merge and are driven by the majority of the gas to have the same power direction again. This process repeats itself, with almost no energy loss throughout the process, and it can always keep most of the gas flowing towards the direction of the third chamber 12.

[0035] The gas flow within valve core 2 is configured to flow in reverse from left to right, combined with... Figure 2 As shown, when the gas flows in the reverse direction, it enters from the lower outlet section and is still diverted. However, because the structure of the annular bend 16 is different from that of the forward flow, the direction of diversion changes. Most of the gas goes around the annular bend 16. During the detour, it continuously collides with the flow channel wall and loses a considerable amount of energy due to the extended path. Furthermore, it merges with the forward-flowing gas during the detour. Since the flow direction is opposite to that of the forward-flowing gas, it loses energy again. After several annular bends 16, the resistance becomes greater and greater. Finally, due to the exhaustion of power, the gas can no longer move forward, thus achieving unidirectional flow of gas in the forward direction.

[0036] Under normal operating conditions, the gas pressure in the upper drill string of the air screw drill bit is high, while the gas pressure in the lower air screw is low. Gas continuously flows into the upper part of the lower air screw motor assembly 7 through the air screw drill bit anti-runaway one-way valve, providing sufficient air volume to ensure the normal operation of the air screw. When tripping out of the drill string, the gas pressure in the upper drill string is low, while the gas in the lower air screw is obstructed from flowing back into the upper drill string. Therefore, a certain pressure is maintained above the lower air screw motor in the third chamber 12, which effectively prevents the air screw from suddenly dropping in pressure due to tripping out of the drill string, which would cause the air volume inside the air screw to increase and the motor speed to suddenly increase, resulting in a "runaway" problem.

[0037] In another technical solution, such as Figure 1-3 As shown, each of the annular bends 16 is composed of a P-shaped structure formed by an arc segment 18 and a straight segment 17 connected together. One end of the arc segment 18 and the straight segment 17 is smoothly connected to form a rounded corner, and the other end of the arc segment 18 and the straight segment 17 forms an acute angle at the connection. The inlet segment extends from the end of the straight segment 17 that has an acute angle with the arc segment 18, and the outlet segment is located at the rounded corner and is consistent with the tangent direction of the corresponding end of the arc segment 18.

[0038] The annular bend 16 has a P-shaped structure resembling a valve, with the outlet at the upper end of P and the inlet at the lower end. Utilizing a combination of straight section 17 and curved section 18 with corresponding docking angles, gas flow direction can be controlled without an additional power mechanism. When gas passes through the anti-runaway check valve of the air screw drill bit in a forward direction, it enters through the check valve inlet. After passing through a straight section 17, the flow is split. Due to the shape of the annular bend 16, only a small portion of the fluid flows towards the end of the curved section 18 with a rounded corner, while the majority of the fluid continues along the straight section. 17. As the fluid continues to flow forward, it will choose a direction again. One direction is to flow towards the exit section with an acute angle, and the other is to flow in the opposite direction, i.e., towards the end of the arc-shaped section 18 with an obtuse angle. The outlet of the previous annular bend 16 is in the same direction as the inlet of the next annular bend 16. Therefore, the gas flowing towards the outlet section can directly enter the next annular bend 16 without losing power or changing the flow direction. The fluid that entered and split in the previous part also converges here and continues to repeat the flow pattern in the previous annular bend 16. This process repeats itself, and there is almost no energy loss in the whole process. When the gas flows in the opposite direction through the anti-runaway check valve of the air screw drill, it will still be diverted, but the structure of the annular bend 16 encountered after the diversion is different, becoming a form with opposite angles. The fluid that went around the previous arc segment 18 will encounter an arc segment 18 when it moves forward. The gas loses a lot of energy when it hits it. Then the gas will rotate nearly 180° and merge with the remaining gas on the straight segment 17 after the first diversion. When the two gases in opposite directions meet, they will lose energy again. After repeating this several times through the annular bend 16, the resistance becomes greater and greater. Finally, due to the exhaustion of power, the gas can no longer move forward, thus realizing the one-way conduction of the valve core 2.

[0039] In another technical solution, such as Figure 1-3 As shown, the diameter of the straight segment 17 is larger than the diameter of the arc segment 18. The straight segment 17 serves as the main channel of the flow path, and most of the gas flows along the straight segments 17 of all the annular bends 16, resulting in minimal energy loss. The arc segment 18 serves as a branch channel of the flow path, mainly working in conjunction with the straight segment 17 to change the gas flow direction.

[0040] In another technical solution, such as Figure 1-3As shown, the valve core 2 includes valve core 2A and valve core 2B, which are semi-cylindrical structures of the same shape and size. Half of the flow channel is located on valve core 2A and the other half on valve core 2B, and their arrangement on valve core 2A and valve core 2B is completely identical. Welding grooves are respectively provided on two edges of valve core 2A and valve core 2B. By welding the corresponding welding grooves of valve core 2A and valve core 2B, valve core 2A and valve core 2B are connected as one unit to form the valve core 2. Welding grooves are milled on two edges of valve core 2A and valve core 2B. The welding grooves of valve core 2A and valve core 2B are butt-jointed and welded. After welding, the surface is polished smooth and then installed into valve body 1 in a specified direction.

[0041] In another technical solution, such as Figure 1-3 As shown, valve core 2A and valve core 2B have two pairs of keyholes symmetrically opened at the end facing the female thread 14. A flat key 3 is inserted and fitted into each pair of keyholes. The end of the flat key 3 near the female thread 14 abuts against the corresponding surface of the adjusting sleeve 4.

[0042] When valve core 2A and valve core 2B are assembled together, two flat keys 3 are inserted into the two pairs of keyholes and positioned by the flat keys 3. Then, welding grooves are welded on the two adjacent edges of valve core 2A and valve core 2B.

[0043] In another technical solution, such as Figure 1-3 As shown, the length of the valve core 2 is proportional to the number of stages of the annular bend 16, where the number of stages represents the number of annular bends 16 arranged axially.

[0044] Each annular bend 16 is called a stage. The flow channel can present different stages as required. The number of stages is different, and the length of the valve core 2 is different. The larger the number of stages, the longer the valve core 2 is, and the longer the internal flow channel of the valve core 2 is, which has a better effect on preventing gas from returning upward. At the same time, the length of the adjusting sleeve 4 can be adjusted according to the length of the valve core 2, so that the valve body 11, valve core 22, adjusting sleeve 44 and the upper drill string are in close contact in the axial direction to achieve axial fixation.

[0045] In another technical solution, such as Figure 1-3 As shown, the reverse control effect ratio of each stage of the annular bend 16 is η%. The reverse control effect is the proportion of gas consumed when gas enters from the outlet section, is first split and then merged through the arc section and the straight section, and then flows out from the inlet section. The number of stages N that the annular bend 16 needs to be designed for under a given maximum displacement is calculated according to the following formula:

[0046]

[0047] Rounding the data obtained on the right up gives the value of the series N.

[0048] The number of stages of the annular bend 16 is set according to the requirement to prevent gas backflow, i.e. the control effect on gas backflow. The larger the number of stages of the flow channel, the greater the resistance, and ultimately the majority of the gas backflow can be blocked.

[0049] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. A one-way valve for preventing runaway operation in air screw drills, characterized in that, include: The valve body has a male thread at one end that is threaded to the anti-drop assembly. The valve body has a through hole along the axial direction. The through hole is divided into a first chamber, a second chamber, and a third chamber with decreasing diameters at the end facing the male thread. The first chamber has a female thread that is threaded to the drill string. The second chamber has a cylindrical structure. The third chamber serves as an air storage chamber. The valve core is installed in the second chamber and is configured to fit the shape of the second chamber. The valve core can rotate circumferentially relative to the second chamber. The valve core has a flow channel along the axial direction. The flow channel includes multiple annular bends with a P-shaped structure arranged sequentially along the axial direction. The annular bend has an inlet section on the side facing the female thread and an outlet section on the side facing the male thread. The inlet section and the outlet section are respectively inclined relative to the valve core axis and symmetrical along the axial direction. The inlet section is positioned facing the outlet section. The outlet section of the previous annular bend and the inlet section of the next annular bend are connected in the same direction. The outlet section and the inlet section at both ends of the flow channel respectively penetrate the corresponding ends of the valve core to form working ports. One working port is connected to the drill string and the other working port is connected to the third chamber. Each of the aforementioned annular bends is composed of a P-shaped structure consisting of interconnected arc-shaped segments and straight segments. One end of the arc-shaped segment and the straight segment are smoothly connected to form a rounded corner, and the other end of the arc-shaped segment and the straight segment form an acute angle at the connection point. The inlet segment extends from the end of the straight segment that forms an acute angle with the arc-shaped segment. The outlet segment is located at the rounded corner and is aligned with the tangent direction of the corresponding end of the arc-shaped segment. The diameter of the straight segment is larger than the diameter of the arc-shaped segment. The adjusting sleeve abuts between the valve core and the drill string, and is used to fix the valve core and the drill string on the valve body axially. The length of the valve core is proportional to the number of stages of the annular bend, where the number of stages represents the axial arrangement of the annular bends. Each stage of the annular bend has a reverse control effect ratio of η, where the reverse control effect is the proportion of gas consumed when gas enters from the outlet section, first splits and then merges through the arc section and the straight section, before exiting from the inlet section. The number of stages N required for the annular bend under a given maximum displacement is calculated using the following formula: Rounding the data obtained on the right up gives the value of the series N.

2. The anti-runaway check valve for air screw drills as described in claim 1, characterized in that, The valve core includes valve core A and valve core B, which are semi-cylindrical structures with the same overall shape and size. Half of the flow channel is located on valve core A and the other half is located on valve core B, and the arrangement of the flow channel on valve core A and valve core B is completely consistent. Welding grooves are respectively provided on two edges of valve core A and valve core B. By welding the welding grooves opposite to those of valve core A and valve core B, valve core A and valve core B are connected as one unit to form the valve core.

3. The anti-runaway check valve for air screw drills as described in claim 1, characterized in that, The valve core A and the valve core B have two pairs of keyholes symmetrically opened at the end facing the female thread. A flat key is inserted and fitted into each pair of keyholes. The end of the flat key near the female thread abuts against the corresponding surface of the adjusting sleeve.

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