Mechanical pressure control type slip fisher capable of freely grabbing and releasing fallen fish

Abstract

A mechanical pressure control type slip fisher capable of freely grabbing and releasing fallen fishes relates to the field of slip fishers and comprises an upper connector, a connecting sleeve, a spring, a fishing barrel, an anti-rotation sleeve, a rotating body, a guide control sleeve and a slip sleeve, the upper connector, the connecting sleeve and the fishing barrel are connected to form a fisher body, and the rotating body, the guide control sleeve and the slip sleeve are connected to form a fisher core string. The fisher core string and the spring are arranged in the fisher body, the spring is supported between the upper connector and the rotating body, the anti-rotating sleeve is installed on the inner side wall of the connecting sleeve, a guide groove is formed in the inner circumferential face of the anti-rotating sleeve, and guide sawteeth are arranged on the upper end face of the anti-rotating sleeve. The guide control sleeve is hung at the lower end of the rotating body, an anti-rotating wedge is arranged on the outer circumferential face of the guide control sleeve, guide control protruding teeth are arranged on the upper end face of the guide control sleeve, the slip sleeve is connected to the lower end of the guide control sleeve, the fisher achieves the free grabbing and releasing function through a combined structure of the anti-rotating sleeve, the rotating body and the guide control sleeve, and the safety, stability and reliability of free grabbing and releasing of fallen fishes can be enhanced.

Description

Technical Field

[0001] The utility model relates to the field of slip salvage devices, in particular to a mechanical pressure-controlled slip salvage device capable of freely catching and releasing fallen fish. Background Art

[0002] The slip salvage device is a specialized tool for sucker rod salvage. It is suitable for salvaging tubular perforated fish, such as downhole tubing, drill pipe, casing milling pipe, packers, water distributors, and production distributors. In actual production, fish salvage operations often require stopping and releasing the fish due to obstacles or production process requirements. Currently, the slip salvage device primarily releases the fish by rotating the sucker rod or drill pipe forward or by cutting weak current screws. The former requires that the sucker rod or drill pipe be free of rotating nipples, while the latter prevents further salvage after release, both of which have significant functional limitations. The utility model patent with announcement number CN210622752U discloses the technical solution of "a pressure-controlled releasable slip salvage device", which specifically "adopts a rotating body and a guide pin matching structure, and limits the movement of the rotating body relative to the cylinder through the grooves on the surface of the rotating body, thereby limiting the axial displacement and radial contraction of the slip, and realizing the cyclic reciprocating operation of salvaging, releasing, and re-salvaging the fish in the well". However, in this technical solution, the weight of the rotating body, the limiting body, the slip and the fish salvaged by the slip is always borne by the guide pin, and the radial shear force is continuously applied to the guide pin through the interaction between the rotating body and the cylinder, especially during the operation. During the alternating cycles of catching and releasing, the guide pin is subjected to significant mechanical impact when interacting with the first and second side guide surfaces, as well as the upper end surfaces of the long and short vertical grooves. This further increases the radial shear force on the guide pin, which also varies in magnitude and direction as the catching and releasing cycles progress. Furthermore, the guide pin's small radial cross-section makes it susceptible to bending fatigue under these dynamic alternating loads, often leading to damage or even breakage during use. This shortens the lifespan of the fish trap, increases production costs, and can sometimes cause production accidents, significantly limiting the widespread application of this technical solution. Therefore, further research and development of novel free-catch-and-release fish slip fish traps is necessary to address the existing technical issues. Utility Model Content

[0003] The purpose of the utility model is to provide a mechanical pressure-controlled slip salvage device capable of freely catching and releasing fallen fish, thereby enhancing the safety, stability and reliability of the free catching and releasing function of fallen fish.

[0004] A mechanical pressure-controlled slip salvage device capable of freely catching and releasing fallen fish, comprising: an upper joint, a connecting sleeve, a spring, an overshot tube, an anti-rotation sleeve, a rotating body, a guide sleeve, and a slip sleeve; the upper joint, the connecting sleeve, and the overshot tube are sequentially connected up and down to form a main body of the overshot tube; an inverted inner conical surface is provided at the lower end of the inner circumference of the overshot tube; the rotating body, the guide sleeve, and the slip sleeve are sequentially connected up and down to form a core string of the overshot tube; the core string of the overshot tube and the spring are jointly installed on the main body of the overshot tube The spring is arranged in the inner cavity of the salvage core string, supported between the upper joint and the rotating body, and applies an elastic force to the salvage core string relative to the salvage body; the anti-rotation sleeve is fixedly installed on the inner side wall of the connecting sleeve, and an axial straight guide groove is provided on the inner circumference of the anti-rotation sleeve. The guide grooves are evenly distributed on the cross-sectional circumference of the anti-rotation sleeve, and are composed of deep grooves and shallow grooves of the same width arranged alternately. The depth of the deep groove is large. The cam is provided with a plurality of guide teeth, each of which is provided with a plurality of guide teeth and a plurality of guide teeth which are arranged in a corresponding axial direction at the same time as the guide teeth.The guide sleeve is rotatably fitted and suspended in the lower end of the rotating body, and a plurality of anti-rotation wedges are provided on the outer circumference thereof, which are arranged in a coordinated manner and in a corresponding axial straight line. The cross-sectional structure of the anti-rotation wedge corresponds to the shallow groove, and is synchronously fitted and correspondingly embedded in the guide grooves provided on the anti-rotation sleeve, so as to limit the rotational movement of the guide sleeve relative to the anti-rotation sleeve and guide the axial movement of the guide sleeve. Guide convex teeth are provided on the upper end surface of the guide sleeve, and the guide convex teeth have an inclined guide surface corresponding to the spatial orientation of the inclined fitting surface at the lower end of the guide wedge, and the inclined guide surface has the same inclination as that of the inclined fitting surface. When the rotating body is fitted in the anti-rotation sleeve, it is prevented from rotating by the guide groove. The rotation limit is maintained, and the inclined guide surface and the inclined matching surface maintain a partial overlap fit, so that a space travel for relative sliding rotation along the matching surface is maintained between the two. When the rotating body moves out of the anti-rotation sleeve and the anti-rotation limit is released, the inclined guide surface can guide the rotating body to rotate under the action of the spring; the slip sleeve is fixedly connected to the lower end of the guide sleeve, and an axially arranged check groove with an opening at the lower end is provided on the slip sleeve, so that the slip sleeve has radial elastic deformation ability, and an inverted outer conical surface is provided on the lower end head. The inverted outer conical surface corresponds to the inverted inner conical surface structure in the overshot tube. When the inverted inner conical surface and the inverted outer conical surface cooperate with each other, the slip sleeve can produce radial contraction deformation to salvage fish in the well.

[0005] The mechanical pressure-controlled slip fish catcher that can freely catch and release fallen fish is preferably provided with a thrust bearing between the rotating body and the spring, and the lower end of the spring is supported on the rotating body by the thrust bearing to reduce the rotational resistance of the rotating body. At the same time, it can also prevent the spring from twisting with the rotation of the rotating body, thereby ensuring the stability of the overall operating function and structural state of the fish catcher.

[0006] The mechanical pressure-controlled cava salvage device that can freely catch and release fallen fish is preferably provided with an outwardly extending annular flange on the outer circumferential surface of the lower part of the rotating body, and a suspension pin with a pin body extending to the inside of the sleeve is installed on the upper side wall of the guide sleeve. The suspension pins are evenly distributed along the circumference of the guide sleeve cross section, and the upper end of the guide sleeve is correspondingly overlapped with the lower end of the rotating body. The pin body of the suspension pin and the annular flange form a balanced overlapping fit, so that the guide sleeve is rotationally fitted and suspended on the rotating body.

[0007] The beneficial effect of the present invention is to provide a mechanical pressure-controlled cava salvage device that can freely catch and release fallen fish, which adopts a corresponding combination structure of an anti-rotation sleeve, a rotating body and a guide sleeve, uses the anti-rotation sleeve to limit the motion trajectory of the guiding and controlling sleeve, cooperates to limit the spatial form of the rotating body, and uses the guide sleeve to drive and control the cyclic transformation of the matching form between the rotating body and the anti-rotation sleeve, and drives the cava sleeve and the salvage tube to cyclically switch between the salvage matching state and the release matching state through the rotating body, so as to realize the free catch and release function of the fish in the well during the salvage operation; in the cyclic conversion process of salvaging and releasing the fish in the well, the rotating body has no No matter between the guide sleeve or the anti-rotation sleeve, axial force is always applied to each other between the end faces. Not only is the force transmitted to each other balanced and stable, but the anti-rotation sleeve, the rotating body and the guide sleeve all have sufficient bearing capacity in the axial direction, which can ensure that the conversion process is completed stably and reliably. It can completely replace the structure in the existing technology that uses the guide pin in an unbalanced state to bear the conversion force, eliminate the phenomenon of production accidents caused by damage or breakage of the guide pin, enhance the safety, stability and reliability of the free release function of falling fish, and can effectively save production costs and improve production efficiency when applied in actual production. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 This is a cross-sectional view of the release structure of a mechanical pressure-controlled slip fish catcher that can freely catch and release fallen fish.

[0009] Figure 2 This is a cross-sectional view of the salvaging structure of a mechanical pressure-controlled cava salvage device that can freely catch and release fallen fish.

[0010] Figure 3 for Figure 2 Cross-sectional view of the middle AA section.

[0011] Figure 4 for Figure 2 Cross-sectional view of the middle BB section.

[0012] Figure 5 This is a three-dimensional structural diagram of the anti-rotation sleeve.

[0013] Figure 6 It is a three-dimensional structural diagram of the rotating body.

[0014] Figure 7 This is a three-dimensional structural diagram of the guidance and control sleeve.

[0015] Among them: 1 is the upper joint, 2 is the connecting sleeve, 3 is the overshot tube, 4 is the spring, 5 is the anti-rotation sleeve, 6 is the rotating body, 7 is the guide sleeve, 8 is the slip sleeve, 9 is the suspension pin, 10 is the thrust bearing, 11 is the deep groove, 12 is the shallow groove, 13 is the guide serration, 14 is the guide wedge, 15 is the anti-rotation wedge, 16 is the guide convex tooth, 17 is the annular flange, 18 is the extension area, 19 is the downhole fish drop, 20 is the inclined guide surface, 21 is the inclined guide surface, 22 is the vertical limit surface, and 23 is the inclined matching surface. DETAILED DESCRIPTION

[0016] Furthermore, the technical solution claimed for protection of the present utility model is described in detail in conjunction with specific embodiments and the accompanying drawings.

[0017] A mechanical pressure-controlled slip fisher capable of freely catching and releasing fallen fish, such as Figures 1 to 4 As shown, it consists of an upper joint 1, a connecting sleeve 2, an overshot tube 3, a spring 4, an anti-rotation sleeve 5, a rotor 6, a guide sleeve 7, a slip sleeve 8, a suspension pin 9 and a thrust bearing 10. The upper joint 1, the connecting sleeve 2 and the overshot tube 3 are sequentially connected up and down to form the overshot body. An inverted inner conical surface is provided at the lower end of the inner circumferential surface of the overshot tube 3. The rotor 6, the guide sleeve 7 and the slip sleeve 8 are sequentially connected up and down to form a overshot core string. The overshot core string is correspondingly arranged in the inner cavity of the overshot body. The thrust bearing 10 is provided at the upper end of the rotor 6, and the spring 4 is provided at the upper end of the thrust bearing 10, supported between the upper joint 1 and the thrust bearing 10.

[0018] The anti-rotation sleeve 5 is fixedly embedded on the inner wall of the connecting sleeve 2. Figure 5 As shown, 8 axially straight guide grooves with the same cross-sectional width are provided on the inner circumference. The guide grooves are evenly distributed along the cross-sectional circumference of the anti-rotation sleeve 5 and are composed of deep grooves 11 and shallow grooves 12 arranged alternately. The depth of the deep grooves 11 is twice the depth of the shallow grooves 12. 8 guide serrations 13 are provided on the upper end face of the anti-rotation sleeve 5 and are continuously and periodically distributed along the circumference. The guide serrations 13 have inclined guide surfaces 21 and vertical limit surfaces 22, which correspond to the opening positions of the guide grooves respectively; the rotating body 6 is a circular cylinder, as shown Figure 6As shown, four guide wedges 14 arranged in an axial straight line are provided in the middle of the outer circumferential surface. The guide wedges 14 are evenly distributed along the circumference of the cross section of the rotating body 6. The cross-sectional structure corresponds to the deep groove 12. The four guide wedges 14 can be synchronously and correspondingly embedded in the four deep grooves 12. An inclined matching surface 23 is provided on the lower end of the guide wedge 14. The inclined matching surface 23 has the same inclination as the inclined guide surface 21 on the guide serration 13. An extended area 18 relative to the guide wedge 14 is provided at the lower end of the rotating body 6, and an annular flange 17 is further provided on the outer circumferential surface of the extended area 18; the guide sleeve 7 is a circular sleeve body, as shown Figure 7 As shown, 8 anti-rotation wedges 15 arranged in an axial straight line are provided on the outer circumference, and the cross-sectional structure of the anti-rotation wedges 15 corresponds to the shallow groove 12. They are evenly arranged along the cross-sectional circumference of the guide sleeve 7 and respectively correspond to the lower end of the anti-rotation sleeve 5 and are embedded in the guide groove opened on the anti-rotation sleeve 5. 8 guide convex teeth 16 are provided on the upper end surface of the guide sleeve 7 and are continuously and periodically distributed along the circumference. The guide convex teeth 16 are in the shape of an umbrella cap, and one side of the tooth surface is an inclined guide surface 20. The inclined guide surface 20 has the same inclination as the inclined matching surface 23 at the lower end of the guide wedge 14. When the rotating body 6 is fitted in the anti-rotation sleeve 5, the inclined guide surface 20 can be aligned with the The inclined mating surface 23 maintains a local overlapping fit. Four suspension pins 9 are installed on the upper side wall of the guide sleeve 7, which are evenly distributed along the circumference. The pin body of the suspension pin 9 extends to the inside of the guide sleeve 7. The upper end of the guide sleeve 7 is fitted on the extended area 18 at the lower end of the rotating body 6. The suspension pin 9 is fitted and hooked on the annular flange 17 to rotate and suspend the guide sleeve 7 on the rotating body 6; the slip sleeve 8 is threaded and fixedly connected to the lower end of the guide sleeve 7. The sleeve body is provided with 8 axially arranged elastic check grooves with openings at the lower end, and an inverted outer conical surface is provided at the lower end. The inverted outer conical surface corresponds to the inverted inner conical surface structure in the salvage tube 3.

[0019] The mechanical pressure-controlled slip fisher capable of freely catching and releasing fallen fish is in a released structural state. Figure 1As shown, the four guide wedges 14 on the rotating body 6 correspond to the four shallow grooves 12 opened on the anti-rotation sleeve 5. Since the guide wedges 14 cannot be inserted into the shallow grooves 12, under the elastic force of the spring 4, the rotating body 6 is fixedly supported on the anti-rotation sleeve 5 through the corresponding cooperation of the inclined matching surface 23 at the lower end of the guide wedge 14 and the inclined guide surface 21 on the guide serration 13 and the anti-rotation limitation of the vertical limiting surface 22 on the adjacent guide serration 13. At this time, the guide control sleeve 7 suspended at the lower end of the rotating body 6 and the slip sleeve 8 connected to the guide control sleeve 7 are lifted upward with the rotating body 6, so that the inverted outer conical surface at the lower end of the slip sleeve 8 and the inverted inner conical surface in the salvage tube 3 are separated and cannot cooperate with each other, so that the slip sleeve 8 cannot catch the fish 19 in the salvage well; in the salvage structure state, as shown Figure 2 As shown, the four guide wedges 14 on the rotating body 6 correspond to the four deep grooves 11 provided on the anti-rotation sleeve 5 and are synchronously inserted into the deep grooves 11 respectively. Under the elastic force of the spring 4, the salvage core string is fully moved downward in the salvage body, and the inverted outer conical surface at the lower end of the slip sleeve 8 forms a corresponding fit with the inverted inner conical surface in the salvage tube 3. At this time, since the rotating body 6 is rotationally limited and fitted in the anti-rotation sleeve 5, the inclined fitting surface 23 at the lower end of the guide wedge 14 can form and maintain a partial overlapping fit with the inclined guide surface 20 on the guide control cam 16, and can transmit the elastic force to the guide control sleeve 7 and the slip sleeve 8 through the rotating body 6, so that the inverted outer conical surface and the inverted inner conical surface generate an interaction force, and the slip sleeve 8 can catch and salvage the fish 19 fallen in the well.

[0020] The mechanical pressure-controlled slip salvage device capable of freely catching and releasing fish described in this embodiment is used to salvage fish that have fallen into a well. The method of use and its working principle are as follows:

[0021] When salvaging fish downhole, the mechanical pressure-controlled slip salvage device capable of freely catching and releasing fish in the structure state is released, such as Figure 1As shown, it is connected to the drill pipe of the drilling tool and sent down the well. When it is sent down to the salvage depth, the overshot tube 3 guides the downhole fish 19 into the overshot body and enters the slip sleeve 8. The drilling tool drill pipe is continuously applied and slowly sent down. The downhole fish 19 will abut against the lower end of the guide sleeve 7, pushing the guide sleeve 7 to move upward relative to the guide sleeve 5 until the inclined guide surfaces 20 on a group of guide convex teeth 16 on the upper end of the guide sleeve 7 respectively cooperate with the inclined lower ends of the four guide wedges 14 on the outer circumference of the rotating body 6. The surface 23 is partially overlapped, and the driving force of the fish falling into the well 19 is transmitted through the mutually matched inclined guide surface 20 and the inclined matching surface 23, so that the core string of the fish catcher moves upward relative to the main body of the fish catcher. When the guide sleeve 7 extends from the upper end of the anti-rotation sleeve 5 to the point where the root of the guide protruding tooth 16 exceeds the height of the tooth tip of the guide serration 13 at the upper end of the anti-rotation sleeve 5, the guide wedge 14 simultaneously breaks away from the circumferential limit of the vertical limit surface 22 on the adjacent guide serration 13. Under the guidance of the inclined guide surface 20 on the guide control cam 16, the rotating body 6 is pushed to rotate, and the four guide wedges 14 are correspondingly guided to the inclined guide surfaces on the adjacent guide serrations 13 and re-form a guiding fit therewith. Since the guide serrations 13 that have re-formed the guiding fit respectively correspond to the deep grooves 11, the guide wedges 14 can be guided by the inclined guide surfaces 21 and respectively fit into the deep grooves 11, so that the rotating body 6 is pushed by the spring 4 to move downward relative to the anti-rotation sleeve 5. After the inclined fitting surface 23 at the lower end of the guide wedge 14 again forms an overlapping fit with the inclined guide surface 20 on the guide control cam 16, the overshot core string forms a structural whole and begins to move downward relative to the overshot body until the slip sleeve 8 drops to the bottom of the overshot tube 3, so that the inverted inner conical surface in the overshot tube 3 forms a corresponding fit with the inverted outer conical surface on the slip sleeve 8, as shown in FIG. Figure 2 As shown, the mechanical pressure-controlled cava salvage device that can freely capture and release fallen fish is transformed into a release structure state. At this time, the drill pipe of the drilling tool is lifted. Under the action of the inverted inner conical surface, the cava sleeve 8 radially elastically contracts and tightens the fallen fish 19 in the well. Continuing to lift the drill pipe of the drilling tool can salvage the fallen fish 19 out of the well.

[0022] When it is necessary to release the fish in the well, the above-mentioned salvage process is terminated and the fish in the well 19 is slowly returned. After the fish in the well 19 is returned and stabilized, the force is continued to be applied to slowly send the drill pipe of the drilling tool. When the fish in the well 19 hits the guide sleeve 7 again, the guide sleeve 7 and the slip sleeve 8 connected to the guide sleeve 7 are pushed upward relative to the anti-rotation sleeve 5. During the movement, the outer conical surface of the lower end of the slip sleeve 8 is gradually separated from the inverted inner conical surface in the overshot tube 3, and the slip sleeve 8 is elastically deformed to recover and loosen to release the fish in the well 19, until the inclined guide surface 20 on the guide convex tooth 16 at the upper end of the guide sleeve 7 is partially engaged with the inclined matching surface 23 at the lower end of the guide wedge 14 again, so that the overshot core string as a whole moves upward relative to the overshot body again. When the guide control sleeve 7 extends from the upper end of the anti-rotation sleeve 5 until the root of the guide control protruding tooth 16 exceeds the tooth tip height of the guide serration 13 on the upper end of the anti-rotation sleeve 5, the guide wedge 14 continues to be guided by the inclined guide surface 20 to the inclined matching surface 23 on the sequentially adjacent guide serration 13, so that the inclined guide surface 20 and the inclined matching surface 23 form a guiding fit with each other. Since the newly introduced guide serrations 13 correspond to the shallow grooves 12 respectively, the guide wedge 1 cannot be inserted into the shallow groove 11 to cause the rotating body 6 to move relative to the anti-rotation sleeve 5. Therefore, the guide wedge 14 is circumferentially limited by the vertical limiting surfaces 22 on the sequentially adjacent guide serrations 13, and is correspondingly supported on the inclined guide surface 21 on the newly introduced guide serrations 13, so that the overshot core string is fixedly connected to the overshot body as a whole. Figure 1 As shown, the mechanical pressure-controlled slip salvage device that can freely capture and release fallen fish is transformed into a release structure state, and the drill pipe of the drilling tool is continuously lifted. The downhole fish 19 will escape from the slip sleeve 8 and the salvage tube 3 and be released in the oil well.

[0023] During the above-mentioned production and use process, when salvaging, the mechanical pressure-controlled slip salvage device that can freely catch and release fallen fish is converted from the released structure state to the salvage structure state. During the conversion process, the guide sleeve 7 transmits an axial force to the rotating body 6 through the inclined guide surface 20 on the upper guide convex tooth 16 and the inclined matching surface 23 at the lower end of the guide wedge 14, so that the rotating body 6 changes the matching state with the anti-rotation sleeve 5; when releasing, the mechanical pressure-controlled slip salvage device that can freely catch and release fallen fish is converted from the salvage structure state to the released structure state. During the conversion process, the guide sleeve 7 still transmits an axial force to the rotating body 6 through the inclined guide surface 20 on the upper guide convex tooth 16 and the inclined matching surface 23, so that the rotating body 6 is fixedly supported on the anti-rotation sleeve 5 through the inclined matching surface 23 at the lower end of the guide wedge 14 and the inclined guide surface 21 on the guide serration 13 at the upper end of the anti-rotation sleeve 5, thereby realizing the matching state conversion again. It can be seen that in the cyclic transformation of the structural state of the mechanical pressure-controlled cava salvage device capable of freely catching and releasing fallen fish described in this embodiment, the rotating body always applies axial force to each other between the upper and lower end surfaces, whether between the guide sleeve or the anti-rotation sleeve. Not only is the force balanced and stable, but the anti-rotation sleeve, the rotating body and the guide sleeve all have sufficient load-bearing capacity in the axial direction, ensuring the safety, stability and reliability of freely catching and releasing fallen fish in the well. In addition, although the guide sleeve 7 is suspended and connected to the rotating body 6 by the suspension pin 9, the suspension pin 9 does not have the function of transmitting force during the transformation of the structural state of the mechanical pressure-controlled cava salvage device capable of freely catching and releasing fallen fish. Its function is only to suspend and lift the guide sleeve 7 and the cava sleeve 8 fixed thereto in the released structural state, so that the inverted outer conical surface at the lower end of the cava sleeve 8 is disengaged from the corresponding cooperation with the inverted inner conical surface in the salvage tube 3. In this structural state, since the fallen fish 19 in the well has been released, the suspension pin 9 It only bears the weight of the guide sleeve 7 and the slip sleeve 8. In the salvage structure state, since the inverted outer conical surface has formed an interactive cooperation with the inverted inner conical surface, the entire weight of the downhole fish 19 and the salvage device core string is borne on the overshot tube 3 through the inverted inner conical surface. At this time, the suspension pin 9 does not bear any force. It can be seen that the provision of the suspension pin 9 will not have any adverse effect on the safety, stability and reliability of the free-catching and releasing function of the mechanical pressure-controlled slip salvage device that can freely catch and release fish described in this embodiment.

Claims

1. A mechanical pressure-controlled slip fisher capable of freely catching and releasing fallen fish, characterized in that: include: An upper joint (1), a connecting sleeve (2), a salvage tube (3), a spring (4), an anti-rotation sleeve (5), a rotating body (6), a guide sleeve (7) and a slip sleeve (8), wherein the upper joint (1), the connecting sleeve (2) and the salvage tube (3) are sequentially connected up and down to form a salvage device body, an inverted inner conical surface is provided at the lower end of the inner circumference of the salvage tube (3), the rotating body (6), the guide sleeve (7) and the slip sleeve (8) are sequentially connected up and down to form a salvage device core string, and the salvage device core string and the spring (4) are jointly arranged in the inner cavity of the salvage device body The spring (4) is arranged on the upper part of the salvage core string, supported between the upper joint (1) and the rotating body (6), and applies an elastic force to the salvage core string relative to the salvage body; the anti-rotation sleeve (5) is fixedly mounted on the inner side wall of the connecting sleeve (2), and an axial straight guide groove is provided on the inner circumference of the anti-rotation sleeve (5). The guide groove is evenly distributed on the cross-sectional circumference of the anti-rotation sleeve (5), and consists of deep grooves (11) and shallow grooves (12) of the same width arranged alternately. The deep grooves (11) are arranged at right angles to the inner circumference of the anti-rotation sleeve (5). The depth is greater than the depth of the shallow groove (12); a guide saw tooth (13) is provided on the upper end surface of the anti-rotation sleeve (5) and is continuously and periodically distributed along the circumference; the guide saw tooth (13) has an inclined guide surface (21) and a vertical limit surface (22), and the setting positions are synchronously corresponding to the guide groove; a guide wedge (14) is provided on the outer circumferential surface of the rotating body (6) and is arranged in a coordinated position corresponding to the axial straight line; the guide wedge (14) can be synchronously with the deep groove (11) or the shallow groove (12) opened on the anti-rotation sleeve (5). The cross-sectional structure corresponds to the deep groove (11). When the guide wedge (14) corresponds to the deep groove (11), the guide wedge (14) can be inserted into the deep groove (11). An inclined matching surface (23) is provided on the lower end of the guide wedge (14). The spatial orientation of the inclined matching surface (23) corresponds to the inclined guide surface (21) on the guide serration (13). The inclined slope is the same as that of the inclined guide surface (21), and the inclined matching surface (23) can form a rotational guide match with the inclined guide surface (21).The guide control sleeve (7) is connected to the lower end of the rotating body (6) by rotational matching and suspension, and an anti-rotation wedge (15) is provided on the outer circumferential surface, and the position of the anti-rotation wedge (15) is coordinated with the axial straight line. The cross-sectional structure of the anti-rotation wedge (15) corresponds to the shallow groove (12), and is synchronously matched and correspondingly embedded in the guide groove opened on the anti-rotation sleeve (5). The upper end surface of the guide control sleeve (7) is provided with a guide control convex tooth (16) distributed continuously and periodically along the circumference. The guide control convex tooth (16) has an inclined guide surface (20) corresponding to the spatial orientation of the inclined matching surface (23) at the lower end of the guide wedge (14). The inclined guide surface (20) ) has the same inclination as that of the inclined matching surface (23); when the rotating body (6) is fitted in the anti-rotation sleeve (5), the inclined guide surface (20) and the inclined matching surface (23) are limited by the anti-rotation of the guide groove, and the inclined guide surface (20) maintains a partial overlap fit with the inclined matching surface (23), so that a space stroke for relative sliding and rotation along the matching surface is maintained between the two; the slip sleeve (8) is fixedly connected to the lower end of the guide sleeve (7); a check groove with an axially arranged lower end opening is provided on the slip sleeve (8); an inverted outer conical surface is provided on the lower end head; the inverted outer conical surface corresponds to the inverted inner conical surface structure in the overshot tube (3); 2. A mechanical pressure-controlled slip scavenger capable of freely catching and releasing fallen fish as claimed in claim 1, characterized in that: A thrust bearing (10) is provided between the rotating body (6) and the spring (4), and the lower end of the spring (4) is supported on the rotating body (6) through the thrust bearing (10).

3. A mechanical pressure-controlled slip scavenger capable of freely catching and releasing fallen fish as claimed in claim 1 or 2, characterized in that: An outwardly extending annular flange (17) is provided on the outer circumferential surface of the lower part of the rotating body (6), and a suspension pin (9) is installed on the upper side wall of the guide sleeve (7), the pin body of which extends to the inside of the sleeve body. The suspension pins (9) are evenly distributed along the circumference of the cross section of the guide sleeve (7), and the upper end of the guide sleeve (7) is correspondingly overlapped with the lower end of the rotating body (6). The pin body of the suspension pin (9) and the annular flange (17) form a balanced hanging fit, so that the guide sleeve (7) is rotationally fitted and suspended on the rotating body (6).

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