CN209742846U - Wall scraper - Google Patents

Abstract

The utility model provides a wall scraper, belonging to the technical field of petroleum drilling, comprising a hollow shaft and at least one group of wall scraping components sleeved on the hollow shaft; the wall scraping component comprises an annular scraping blade, a sliding bearing and an annular pressing sheet; the annular scraping blade is sleeved on the hollow shaft, a sliding bearing is arranged between the annular scraping blade and the hollow shaft, and a spring is arranged between the sliding bearing and the annular pressing scraping blade; the annular pressing plate comprises a first pressing ring, a second pressing ring and a plurality of pressing strips connected to two ends of the first pressing ring and the second pressing ring, and the first pressing ring and the second pressing ring are used for limiting the axial displacement of the annular scraping blade along the hollow shaft; the pressing strip is used for limiting the radial displacement of the annular scraping blade along the hollow shaft; the annular scraping piece positioned between two adjacent pressing strips is provided with a spiral convex tooth, the spiral convex tooth protrudes out of the surface of the pressing strip, and two adjacent spiral convex teeth form a diversion trench. The utility model provides a scrape wall ware can reduce and scrape the wall ware and meet the emergence of card phenomenon and promote and scrape wall efficiency and scrape the wall effect.

Description

wall scraper

Technical Field

The utility model relates to an oil drilling technical field especially relates to a scrape wall ware.

Background

In the process of oil exploitation, a mud cake on a well wall needs to be scraped, and then casing cementing or well logging is carried out so as to ensure the cementing quality and the accuracy of well logging data.

At present, a wall scraper is often adopted to scrape mud cakes on a well wall so that the mud cakes on the well wall fall off from the well wall into a well bore and are carried away to the ground along with backwashing well liquid. The scraping blade of the existing wall scraper is fixed and does not rotate, and due to the fact that the well wall is irregular or the quality of a well wall mud cake is poor (the shape is irregular), when the wall scraper is used for scraping the wall in a well, the wall scraper is easy to clamp, and the wall scraper needs to be repeatedly lifted up and down to continue the wall scraping operation.

When the existing wall scraper is used for wall scraping operation, the wall scraper is easy to be blocked underground, so that the wall scraping efficiency is low and the wall scraping effect is poor.

SUMMERY OF THE UTILITY MODEL

The utility model provides a scrape wall ware can reduce and scrape the emergence that wall ware meets the card phenomenon in the pit to and promote and scrape wall efficiency and scrape the wall effect.

In order to achieve the above purpose, the utility model adopts the following technical scheme:

The utility model provides a wall scraper, which comprises a hollow shaft and at least one group of wall scraping components sleeved on the hollow shaft; the wall scraping component comprises an annular scraping blade, a sliding bearing and an annular pressing sheet; the annular scraping blade is sleeved on the hollow shaft, the sliding bearing is arranged between the annular scraping blade and the hollow shaft, and a spring is arranged between the sliding bearing and the annular pressing scraping blade; the pressing ring comprises a first pressing ring, a second pressing ring and a plurality of pressing strips; the first pressing ring and the second pressing ring are respectively arranged at two ends of the annular scraping blade and are used for limiting the axial displacement of the annular scraping blade along the hollow shaft; the pressing strips are arranged along the circumferential direction of the hollow shaft at intervals, one end of each pressing strip is connected with the first pressing ring, the other end of each pressing strip is connected with the second pressing ring, and the pressing strips are used for limiting the radial displacement of the annular scraping blade along the hollow shaft; the annular scraping piece positioned between two adjacent pressing strips is provided with spiral convex teeth, the spiral convex teeth protrude out of the surfaces of the pressing strips, and two adjacent spiral convex teeth form a diversion trench.

further, the wall scraping assembly further comprises a first thrust ring and a second thrust ring; the first thrust ring is arranged on one side, away from the annular scraping blade, of the first pressing ring, and the first thrust ring is abutted to the first pressing ring; the second thrust ring is arranged on one side, away from the annular scraping blade, of the second pressing ring, and the second thrust ring is abutted to the second pressing ring.

Furthermore, the edge of the spiral convex tooth is provided with an arc-shaped surface.

further, the wall scraper comprises a first wall scraping component and a second wall scraping component, the first wall scraping component comprises a first annular scraping blade, the first annular scraping blade is provided with right spiral convex teeth, and a first diversion trench is formed between every two adjacent right spiral convex teeth; the second wall scraping assembly comprises a second annular scraping blade, the second annular scraping blade is provided with left spiral convex teeth, and a second diversion trench is formed between every two adjacent left spiral convex teeth.

Further, the sliding bearing comprises an inner bushing, an outer bushing and two bearing covers; the two bearing covers are arranged at two ends of the inner bushing and the outer bushing, a cavity is formed between the inner bushing and the outer bushing, and lubricating oil is arranged in the cavity; the inner bushing is provided with an oil filling hole, the lubricating oil flows to the position between the inner bushing and the hollow shaft through the oil filling hole, and a lubricating oil film is formed on the surface of the hollow shaft.

Furthermore, a first mounting hole is formed in one side, close to the annular scraping blade, of the outer bushing, and a second mounting hole opposite to the first mounting hole is formed in the annular scraping blade; and two ends of the spring are respectively fixed in the first mounting hole and the second mounting hole.

Further, a positioning shaft shoulder for mounting the inner bushing is arranged on the surface of the hollow shaft.

Furthermore, internal threads are arranged at two ends of the hollow shaft, and the hollow shaft is connected to the drill rod through threads.

Further, the annular scraping blade comprises a plurality of elastic scraping blades; each elastic scraping blade is respectively pressed in an interval formed by two adjacent pressing strips, and the spiral convex teeth are positioned on the elastic scraping blades.

Furthermore, the first pressing ring, the second pressing ring and the pressing strip are molded into an integrated structure.

Compared with the prior art, the wall scraper provided by the utility model has the following advantages;

The utility model provides a wall scraper, wherein annular preforming cup joints on the hollow shaft through slide bearing, makes annular preforming hollow shaft relatively rotate, and the surface of annular preforming is provided with spiral dogtooth and guiding gutter, puts the in-process of scraping wall scraper under, and liquid erodees the guiding gutter in the well, can drive annular preforming rotatory to utilize spiral dogtooth to cut the piece to rubbing the mud cake of the wall of a well, can realize brushing the piece to the mud cake limit, has promoted and has scraped wall operating efficiency and reduced the phenomenon of meeting the card in the pit of scraping wall scraper.

In addition, a spring is arranged between the annular scraping blade and the sliding bearing, so that the annular pressing sheet can stretch out and draw back along the axial direction of the hollow shaft, and when the annular scraping blade bears larger resistance, the annular scraping blade shrinks towards one side of the hollow shaft, so that the phenomenon of underground clamping of the wall scraper can be reduced.

In addition to the technical problems, technical features constituting technical solutions, and advantageous effects brought by the technical features of the technical solutions described above, other technical problems, technical features included in the technical solutions, and advantageous effects brought by the technical features that can be solved by the wall scraper provided by the present invention will be described in further detail in the detailed description of the embodiments.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the embodiments of the present invention or the description of the prior art will be briefly described below, it should be apparent that the drawings in the following description are only a part of the embodiments of the present invention, and for those skilled in the art, other drawings can be obtained without creative efforts.

Fig. 1 is a schematic overall structural diagram of a wall scraper according to an embodiment of the present invention;

Fig. 2 is a schematic view of an internal structure of a wall scraper according to an embodiment of the present invention;

FIG. 3 is an enlarged view taken at A in FIG. 2;

fig. 4 is a schematic structural diagram of a ring pressing plate according to an embodiment of the present invention;

fig. 5 is a schematic structural component view of a first wall scraping assembly according to an embodiment of the present invention;

fig. 6 is a schematic structural component view of a second wall scraping assembly according to an embodiment of the present invention;

fig. 7 is a schematic structural diagram of a sliding bearing according to an embodiment of the present invention;

Fig. 8 is a schematic structural diagram of a bearing cap according to an embodiment of the present invention.

10-hollow shaft, 20-annular pressing sheet,

21-a first press ring, 22-a second press ring,

23-a bead, 30-an annular wiper blade,

31-right spiral convex teeth, 32-left spiral convex teeth,

40-spring, 50-plain bearing,

51-inner liner, 52-outer liner,

53-oil filler hole, 54-bearing cover,

55-round cover plate, 56-fixed ring.

Detailed Description

in order to make the above objects, features and advantages of the present invention more comprehensible, embodiments of the present invention are described in detail with reference to the accompanying drawings. It is obvious that the described embodiments are only some of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by a person skilled in the art without creative efforts all belong to the protection scope of the present invention.

In the description of the embodiments of the present invention, it should be understood that the terms "central," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used in the orientation or positional relationship indicated in the drawings for convenience of description and simplicity of description, and do not indicate or imply that the device or element so indicated must have a particular orientation, be constructed and operated in a particular orientation, and therefore should not be considered as limiting.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the embodiments of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.

As shown in fig. 1 to 4, the wall scraper provided by the embodiment of the present invention includes a hollow shaft 10 and at least one set of wall scraping assemblies sleeved on the hollow shaft 10; the wall scraping component comprises an annular scraping blade 30, a sliding bearing 50 and an annular pressing sheet 20; the annular scraping blade 30 is sleeved on the hollow shaft 10, a sliding bearing 50 is arranged between the annular scraping blade 30 and the hollow shaft 10, and a spring 40 is arranged between the sliding bearing 50 and the annular pressing scraping blade; the pressing ring 20 comprises a first pressing ring 21, a second pressing ring 22 and a plurality of pressing bars 23; the first pressing ring 21 and the second pressing ring 22 are respectively arranged at two ends of the annular scraping blade 30 and used for limiting the axial displacement of the annular scraping blade 30 along the hollow shaft 10; the plurality of pressing strips 23 are arranged at intervals along the circumferential direction of the hollow shaft 10, one end of each pressing strip 23 is connected with the first pressing ring 21, the other end of each pressing strip 23 is connected with the second pressing ring 22, and the pressing strips 23 are used for limiting the radial displacement of the annular scraping blade 30 along the hollow shaft 10; the annular scraping blade 30 positioned between two adjacent pressing strips 23 is provided with spiral convex teeth, the spiral convex teeth protrude out of the surfaces of the pressing strips 23, and two adjacent spiral convex teeth form a diversion trench.

Specifically, the wall scraper includes hollow shaft 10, and hollow shaft 10 is used for connecting the wall scraper on the drilling rod, can be provided with the internal thread or the external screw thread that are used for with drilling rod threaded connection at the both ends of hollow shaft 10, and correspondingly, be provided with at the drilling rod with hollow shaft 10 female thread complex external screw thread, or be provided with the female thread of the male thread complex of hollow shaft 10.

at least one wall scraping assembly is sleeved on the hollow shaft 10 and used for scraping the wall of the well wall, so that mud cakes adhered to the well wall are removed from the well wall. The wall scraping component comprises an annular scraping blade 30, a sliding bearing 50 and an annular pressing sheet 20; the annular scraping blade 30 is of an annular structure, the annular scraping blade 30 is sleeved on the hollow shaft 10, a sliding bearing 50 is arranged between the annular scraping blade 30 and the hollow shaft 10, the sliding bearing 50 is connected with the annular scraping blade 30 through a spring 40, the annular scraping blade 30 can stretch and deform along the radial direction of the hollow shaft 10, the operation radius of the annular scraping blade 30 is changed, in addition, the annular scraping blade 30 is connected on the hollow shaft 10 through the sliding bearing 50, the annular scraping blade 30 can rotate relative to the hollow shaft 10, circumferential scraping is carried out on mud cakes adhered to the wall of a well, and the wall scraping operation efficiency is improved.

the outer side of the annular scraping blade 30 is sleeved with an annular pressing sheet 20, and the annular pressing sheet 20 comprises a first pressing ring 21, a second pressing ring 22 and a pressing strip 23 connected between the first pressing ring 21 and the second pressing ring 22; first clamping ring 21 and second clamping ring 22 are the loop configuration, and first clamping ring 21 and second clamping ring 22 all are provided with the shoulder hole, and the shoulder hole includes first hole section and second hole section, and the internal diameter of first hole section is greater than the internal diameter of second hole section, and the transitional coupling department of first hole section and second hole section forms the step face.

the first pressing ring 21 and the second pressing ring 22 are respectively sleeved at two ends of the annular scraping blade 30, the annular scraping blade 30 is pressed in the first hole section, the end face of the annular scraping blade 30 abuts against the step face, the first pressing ring 21 and the second pressing ring 22 are fixed on the hollow shaft 10 through the second hole section, and therefore the annular scraping blade 30 is limited to move axially along the hollow shaft 10.

it can be understood that the first press ring 21 and the second press ring 22 are fixed to the hollow shaft 10 by threads, that is, the inner surface of the second hole segment of the first press ring 21 and the inner surface of the second hole segment of the second press ring 22 are both provided with internal threads, and the hollow shaft 10 is provided with external threads for matching with the first press ring 21 or the second press ring 22.

A plurality of pressing strips 23 are uniformly arranged between the first pressing ring 21 and the second pressing ring 22, each pressing strip 23 is in a strip shape, one end of each pressing strip 23 is fixedly connected with the surface of the first pressing ring 21, the other end of each pressing strip is fixedly connected with the surface of the second pressing ring 22, each pressing strip 23 has certain rigidity, and the pressing strips are attached to the surface of the annular scraping blade 30, so that the displacement of the annular scraping blade 30 in the radial direction of the hollow shaft 10 can be limited, and the annular scraping blade 30 is prevented from falling off from the hollow shaft 10. It can be understood that the bead 23 may be connected to the first pressing ring 21 or the second pressing ring 22 by welding, or the first pressing ring 21, the second pressing ring 22 and the bead 23 are an integrated structure, and in this embodiment, the ring pressing plate 20 is preferably manufactured into an integrated structure, which can enhance the structural strength of the ring pressing plate 20 and prevent the bead 23 from falling off from the first pressing ring 21 and the second pressing ring 22.

An interval is formed between every two adjacent pressing strips 23, a plurality of spiral convex teeth which are arranged in sequence are arranged on the surface of the annular scraping blade 30 positioned at the interval, and the spiral convex teeth protrude out of the surface of the pressing strips 23, so that the annular scraping blade 30 can be ensured to be in contact with mud cakes on a well wall. Two adjacent spiral convex teeth form a diversion trench, and liquid flow erodes the diversion trench, can drive annular doctor blade 30 and rotate relative to hollow shaft 10, realizes scouring the side of mud cake and scraping, has promoted wall scraping operation efficiency and has reduced the probability of scraping wall ware and meeting the card in the pit.

When the wall scraper provided by the utility model is used for scraping the wall of a well, when the wall scraper is placed down, the annular scraping blade 30 is deformed in a stretching way when encountering the irregular part of the well wall, so that the operation range of the annular scraping blade 30 is reduced, the annular scraping blade 30 is deviated towards one side of the hollow shaft 10, and the phenomenon of blocking of the annular scraping blade 30 is avoided; in addition, in the process of lowering the wall scraper, the wall scraper and liquid in the well form relative motion, so that the liquid erodes the diversion trench of the annular scraping blade 30, the annular scraping blade 30 can be driven to rotate, the well wall and the annular scraping blade 30 are eroded, mud cakes adhered to the well wall and the scraping blade fall off and enter liquid flow, and the wall scraping operation efficiency and the wall scraping effect can be improved.

In this embodiment, the wall scraping assembly further comprises a first thrust ring and a second thrust ring; the first thrust ring is arranged on one side, far away from the annular scraping blade 30, of the first pressing ring 21, the first thrust ring is abutted to the first pressing ring 21, the second thrust ring is arranged on one side, far away from the annular scraping blade 30, of the second pressing ring 22, and the second thrust ring is abutted to the second pressing ring 22.

Specifically, the first thrust ring and the second thrust ring are both annular, inner threads are arranged on the inner walls of the first thrust ring and the second thrust ring, the first thrust ring and the second thrust ring are connected to the hollow shaft 10 through threads, and one side of the first thrust ring is abutted to the first pressing ring 21 to prevent the first pressing ring 21 from moving along the axial direction of the hollow shaft 10; similarly, one side of the second thrust ring abuts against the second pressure ring 22, and the second pressure ring 22 is prevented from moving in the axial direction of the hollow shaft 10. By sleeving the first thrust ring and the second thrust ring on the hollow shaft 10, the stability of the installation of the annular scraping blade 30 on the hollow shaft 10 can be further improved, the annular scraping blade 30 can be effectively prevented from moving along the axial direction of the hollow shaft 10, and the efficiency of wall scraping operation is further improved.

Further, in order to reduce the friction force between the annular scraping blade 30 and the well wall and avoid the phenomenon of blocking of the wall scraper, the edges of the spiral convex teeth are subjected to fillet treatment to form an arc-shaped surface at the tops of the spiral convex teeth. It can be understood that, in order to prevent the mud cake from blocking the diversion trench and preventing the mud cake from adhering to the annular scraping blade 30, the diversion trench can be set to be a trapezoidal groove, and the size of the bottom surface of the trapezoidal groove far away from one side of the hollow shaft 10 is larger than that of the bottom surface of the trapezoidal groove towards one side of the hollow shaft 10, so that the mud cake in the diversion trench can be easily thrown out when the annular scraping blade 30 rotates automatically, the annular scraping blade 30 is convenient to clean, and the wall scraping operation efficiency is improved.

As shown in fig. 5 and 6, in order to improve the efficiency of the wall scraping operation, the wall scraper provided by the embodiment comprises a plurality of wall scraping assemblies; specifically, a plurality of wall scraping assemblies are arranged at intervals along the axial direction of the hollow shaft 10, and the wall scraping assemblies can be divided into a first wall scraping assembly and a second wall scraping assembly according to different rotation directions of the spiral convex teeth arranged on the wall scraping assemblies; the first wall scraping assembly comprises a first annular scraping blade, the first annular scraping blade is provided with right spiral convex teeth 31, and two adjacent right spiral convex teeth 31 form a first diversion trench; the second wall scraping assembly comprises a second annular scraping blade, the second annular scraping blade is provided with left spiral convex teeth 32, and two adjacent left spiral convex teeth 32 form a second diversion trench. When the wall scraper is lowered into the well along with the drill rod, the liquid scours the first diversion trench to drive the first annular scraping blade to rotate anticlockwise and scrape mud cakes on the well wall; similarly, the liquid scouring the second diversion trench can drive the second annular scraping blade to rotate clockwise and scrape the mud cake on the well wall. The wall scraper is provided with the first annular scraping blade and the second annular scraping blade which rotate to different directions, so that mud cakes on a well wall can be scraped forwards or backwards, and the wall scraping operation effect is improved.

as shown in fig. 7 and 8 in combination with fig. 3, the plain bearing 50 in the present embodiment includes an inner bush 51, an outer bush 52, and bearing caps 54 at both ends; two bearing covers 54 are installed at two ends of the inner bush 51 and the outer bush 52, a cavity is formed between the inner bush 51 and the outer bush 52, and lubricating oil is arranged in the cavity; the inner bush 51 is provided with oil holes 53, and lubricating oil flows between the inner bush 51 and the hollow shaft 10 through the oil holes 53, and forms a lubricating oil film on the surface of the hollow shaft 10.

specifically, the inner bush 51 is sleeved in the outer bush 52, the inner bush 51 is provided with a plurality of oil holes 53, the plurality of oil holes 53 are uniformly distributed on the inner bush 51, two ports of the inner bush 51 are flush with two ports of the outer bush 52, a cavity is formed between the outer side wall of the inner bush 51 and the inner side wall of the outer bush 52, bearing covers 54 are respectively installed at two ends of the inner bush 51 and the outer bush 52, and the bearing covers 54 are used for sealing the cavity. The bearing cover 54 comprises a circular cover plate 55, a fixed ring 56 is arranged on the circular cover plate 55, the fixed ring 56 and the circular cover plate 55 are coaxially arranged, and the diameter of the fixed ring 56 is smaller than that of the circular cover plate 55; the outer side wall of the fixing ring 56 is provided with external threads, the inner bushing 51 and the outer bushing 52 are provided with internal threads matched with the external threads of the fixing ring 56, and the fixing ring 56 is connected between the inner bushing 51 and the outer bushing 52 through the internal threads and the external threads, so that the inner bushing 51 and the outer bushing 52 are fixed and sealed.

further, in order to improve the supporting strength between the inner bushing 51 and the outer bushing 52, a plurality of supporting columns are arranged between the inner bushing 51 and the outer bushing 52, one ends of the supporting columns are fixed on the outer side wall of the inner bushing 51, and the other ends of the supporting columns are abutted to the inner side wall of the outer bushing 52, so that a stable force transmission structure is formed, the pressure resistance of the sliding bearing 50 is enhanced, and the service life of the sliding bearing is prolonged.

on the basis of the above embodiment, one side of the outer bushing 52 close to the annular blade 30 is provided with a first mounting hole, and the annular blade 30 is provided with a second mounting hole opposite to the first mounting hole; both ends of the spring 40 are fixed in the first mounting hole and the second mounting hole, respectively. Specifically, the annular scraping blade 30 is connected to the sliding bearing 50 through the spring 40, so that the scraping range of the annular scraping blade 30 is adjustable, and the occurrence of the blocking phenomenon of the annular scraping blade 30 is reduced. In order to facilitate the installation of the spring 40, a first installation hole may be formed in the outer bushing 52 of the sliding bearing 50, a second installation hole may be formed in a side of the annular blade 30 close to the sliding bearing 50, and the first installation hole is opposite to the second installation hole, and both ends of the spring 40 may be respectively installed in the first installation hole and the second installation hole, thereby improving the stability of the installation of the spring 40 between the annular blade 30 and the sliding bearing 50.

On the basis of the above-described embodiment, the surface of the hollow shaft 10 is provided with a positioning shoulder for mounting the inner bush 51. Specifically, in order to further limit the displacement of the annular scraping blade 30 along the axial direction of the hollow shaft 10, a set of positioning shoulders may be disposed on the hollow shaft 10, an inner bushing 51 of the sliding bearing 50 is embedded between the two positioning shoulders to prevent the sliding bearing 50 from moving along the axial direction of the hollow shaft 10, the sliding bearing 50 is connected to the annular scraping blade 30 through a spring 40, and a first pressing ring 21 and a second pressing ring 22 are respectively mounted at two ends of the annular scraping blade 30, and under the action of the first pressing ring 21, the second pressing ring 22 and the positioning shoulders, in the wall scraping operation, the movement of the annular scraping blade 30 along the direction of the hollow shaft 10 may be limited, thereby improving the wall scraping operation efficiency and the operation effect.

In this embodiment, internal threads are provided at both ends of the hollow shaft 10, and the hollow shaft 10 is connected to the drill rod through the threads. Specifically, for being convenient for to scrape the wall ware and connect on the drilling rod to can transfer to the well along with the drilling rod and scrape the wall operation, be provided with the internal thread at the both ends of hollow shaft 10, the drilling rod is provided with the external screw thread with the internal thread matched with of hollow shaft 10 with the junction of hollow shaft 10, scrape the wall ware and pass through hollow shaft 10 and connect on the drilling rod, be convenient for maintain and change and scrape the wall ware. It will be appreciated that the hollow shaft 10 is not limited to the threaded connection described above, and may alternatively be connected in other ways.

in this embodiment, in order to avoid the annular scraping blade 30 from being jammed during the wall scraping operation and improve the wall scraping operation efficiency, the annular scraping blade 30 may be made of a rigid material with certain elasticity, and when the annular scraping blade 30 is used for the wall scraping operation, the elastic deformation may occur in a self-adaptive manner when encountering a place with a large resistance, thereby reducing the occurrence of the jamming phenomenon of the annular scraping blade 30.

It will be appreciated that the annular wiper 30 comprises a plurality of elastic wipers, each of which is respectively pressed against the space formed by two adjacent beads 23, on which the helical teeth are located. Specifically, the annular scraping blade 30 can be made of a whole ring or can be divided into a plurality of elastic scraping blades, the elastic scraping blades are respectively arranged in an interval formed by two adjacent pressing strips 23, the pressing strips 23 are pressed at the edges of the elastic scraping blades, and spiral convex teeth arranged on the elastic scraping blades protrude out of the surface of the pressing strips 23 and are used for being in contact with mud cakes of the well wall. Each elastic scraper is provided with a second mounting hole for mounting the spring 40, the operation range of each elastic scraper can be adjusted, and the probability of the wall scraper encountering a card can be reduced.

finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; although the present invention has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; such modifications and substitutions do not depart from the spirit and scope of the present invention.

Claims (10)

1. A wall scraper is characterized by comprising a hollow shaft and at least one group of wall scraping components sleeved on the hollow shaft;

The wall scraping component comprises an annular scraping blade, a sliding bearing and an annular pressing sheet;

the annular scraping blade is sleeved on the hollow shaft, the sliding bearing is arranged between the annular scraping blade and the hollow shaft, and a spring is arranged between the sliding bearing and the annular pressing scraping blade;

The pressing ring comprises a first pressing ring, a second pressing ring and a plurality of pressing strips;

The first pressing ring and the second pressing ring are respectively arranged at two ends of the annular scraping blade and are used for limiting the axial displacement of the annular scraping blade along the hollow shaft;

The pressing strips are arranged along the circumferential direction of the hollow shaft at intervals, one end of each pressing strip is connected with the first pressing ring, the other end of each pressing strip is connected with the second pressing ring, and the pressing strips are used for limiting the radial displacement of the annular scraping blade along the hollow shaft;

The annular scraping piece positioned between two adjacent pressing strips is provided with spiral convex teeth, the spiral convex teeth protrude out of the surfaces of the pressing strips, and two adjacent spiral convex teeth form a diversion trench.

2. The wall scraper of claim 1 wherein said wall scraper assembly further comprises a first thrust ring and a second thrust ring;

The first thrust ring is arranged on one side, away from the annular scraping blade, of the first pressing ring, and the first thrust ring is abutted to the first pressing ring;

The second thrust ring is arranged on one side, away from the annular scraping blade, of the second pressing ring, and the second thrust ring is abutted to the second pressing ring.

3. The wall scraper of claim 1 wherein the edges of said helical lobes are provided with arcuate surfaces.

4. the wall scraper of claim 1, wherein said wall scraper comprises a first wall scraper assembly and a second wall scraper assembly;

The first wall scraping assembly comprises a first annular scraping blade, the first annular scraping blade is provided with right spiral convex teeth, and a first diversion trench is formed between every two adjacent right spiral convex teeth;

the second wall scraping assembly comprises a second annular scraping blade, the second annular scraping blade is provided with left spiral convex teeth, and a second diversion trench is formed between every two adjacent left spiral convex teeth.

5. The wall scraper of claim 1 wherein said slide bearing comprises an inner bushing, an outer bushing and two bearing caps;

The two bearing covers are arranged at two ends of the inner bushing and the outer bushing, a cavity is formed between the inner bushing and the outer bushing, and lubricating oil is arranged in the cavity;

The inner bushing is provided with an oil filling hole, the lubricating oil flows to the position between the inner bushing and the hollow shaft through the oil filling hole, and a lubricating oil film is formed on the surface of the hollow shaft.

6. the wall scraper of claim 5 wherein a side of said outer bushing adjacent said annular scraper is provided with a first mounting hole, said annular scraper being provided with a second mounting hole opposite said first mounting hole;

and two ends of the spring are respectively fixed in the first mounting hole and the second mounting hole.

7. Wall scraper according to claim 5, characterized in that the surface of the hollow shaft is provided with a positioning shoulder for mounting the inner bushing.

8. The wall scraper of claim 1 wherein said hollow shaft is internally threaded at both ends and said hollow shaft is threadedly attached to a drill stem.

9. the wall scraper of claim 1 wherein said annular scraper comprises a plurality of resilient scrapers;

Each elastic scraping blade is respectively pressed in an interval formed by two adjacent pressing strips, and the spiral convex teeth are positioned on the elastic scraping blades.

10. the wall scraper of claim 1 wherein said first and second clamping rings and bead are injection molded as a unitary structure.