CN210289650U - Sand washing joint and sand washing device - Google Patents

Abstract

The utility model discloses a sand washing connects and sand washing device, this sand washing connects includes: the locking piece comprises an upper joint, a central pipe, a clamping cylinder, a conical surface ring and a locking piece arranged on the upper joint. The center tube is connected with the top connection is coaxial, and the center tube has first end and second end, and the top connection is located the first end, and the second end has the locating part. A buckle section of thick bamboo slip suit is on the center tube, is equipped with a plurality of annular archs that are used for with oil pipe joint on the outer wall of a buckle section of thick bamboo, is equipped with axially extended open slot on the terminal surface that a buckle section of thick bamboo is close to the second end. The conical surface ring is sleeved on the central tube and located between the first end and the limiting part, one end, close to the first end, of the conical surface ring is close to one end of the second end, the outer diameter of the conical surface ring is gradually increased, the conical surface ring is inserted into the buckle barrel, and the outer wall of the conical surface ring is in contact with the inner wall of the buckle barrel. The locking piece supports against one end of the buckle barrel. The utility model discloses simplify sand washing instrument and oil pipe's connected mode, save the time of connection process cost, improve sand washing efficiency.

Description

Sand washing joint and sand washing device

Technical Field

The utility model relates to an oil recovery engineering field, in particular to sand washing connects and sand washing device.

Background

In the production process of the oil field, the sand of the oil well can be produced due to reasons such as cementing and loosening of an oil layer, and if the sand of the oil well cannot be cleaned in time after the sand is produced, the sand is precipitated in the well, so that the oil pipe is blocked, and the production of the oil field is not facilitated. In order to avoid sand production from an oil well from affecting oil field production, sand washing operation is usually required.

At present, during sand washing operation, a cement truck is generally used for pumping high-speed sand washing liquid into an oil pipe, and sand in a formation is washed to the ground from a space between the oil pipe and a casing pipe under the action of the high-speed sand washing liquid.

In the process of implementing the present invention, the inventor finds that the prior art has at least the following problems:

the connection of a sand washing tool (such as a drill rod) used in the prior sand washing operation and an oil pipe usually adopts a union joint, and when the union joint is adopted for connection, a tool such as a pipe wrench is required to screw the union joint and the sand washing tool so as to ensure the tightness of the union joint during threaded connection, and the connection process takes longer time, is easy to influence the sand washing efficiency and is not beneficial to use.

SUMMERY OF THE UTILITY MODEL

The embodiment of the utility model provides a sand washing connects and sand washing device can simplify sand washing instrument and oil pipe's connected mode, saves the time of connection process cost, improves sand washing efficiency. The technical scheme is as follows:

in a first aspect, an embodiment of the present invention provides a sand washing joint, the sand washing joint includes: an upper joint; a center tube coaxially coupled to the top sub, the center tube having opposite first and second ends, the top sub being located at the first end, the second end having a stop; the buckle barrel is slidably sleeved on the central pipe, a plurality of annular bulges used for being clamped with internal threads on the inner wall of the oil pipe are arranged on the outer wall of the buckle barrel, and at least two axially extending open grooves are formed in the end face, close to the second end, of the buckle barrel; the conical surface ring is sleeved on the central tube and positioned between the first end and the limiting piece, the outer diameter of the conical surface ring is gradually increased from one end, close to the first end, of the conical surface ring to one end, close to the second end, of the conical surface ring, the conical surface ring is inserted into the buckle barrel, and the outer wall of the conical surface ring is in contact with the inner wall of the buckle barrel; and the locking piece is arranged on the upper joint and is abutted against one end of the buckle barrel.

The embodiment of the utility model provides an in the implementation, follow the notch of open slot extremely the tank bottom of open slot, the distance of two relative cell walls on the open slot reduces gradually.

In another implementation of the embodiment of the present invention, the sand washing joint further includes an annular rubber hose sleeved on the central tube, and the annular rubber hose is located between the conical ring and the locating part.

The utility model discloses in another kind of realization of embodiment, cyclic annular rubber tube has a plurality ofly, adjacent two be equipped with the suit between the cyclic annular rubber tube and be in annular baffle on the center tube.

The utility model discloses in another kind of implementation of embodiment, the locking piece includes locking lagging and two locking handles, the fixed suit of locking lagging is in on the top connection, be equipped with the edge on the locking lagging two curb plates of top connection axial extension, two curb plate parallel mutual disposition, follow on two curb plates the epaxial a plurality of pinholes of having equally distributed of top connection, two be equipped with on the locking handle with pinhole complex round pin axle, two the locking handle all passes through the round pin axle cartridge is in on two curb plates.

The utility model discloses in another kind of implementation of embodiment, the locking piece includes locking lagging and two locking handles, the fixed suit of locking lagging is in on the top connection, be equipped with the edge on the locking lagging two curb plates of top connection axial extension, two curb plate parallel mutual disposition, be equipped with coaxial distribution's pinhole, two on two curb plates the locking handle rotationally installs through the round pin axle on the curb plate, two the locking handle have with the adjustment curved surface that a buckle section of thick bamboo offsets, the adjustment curved surface is apart from the distance of the central line of round pin axle changes gradually.

In another implementation of the embodiment of the present invention, the inner wall surface of the fastening cylinder and the conical surface ring are provided with protrusions extending along the radial direction of the fastening cylinder.

In another implementation of the embodiment of the present invention, the fastening cylinder is a spring steel structure.

In another implementation of the embodiment of the present invention, the position-limiting member is a nut.

In a second aspect, an embodiment of the present invention provides a sand washing device, which includes the sand washing joint described above.

The embodiment of the utility model provides a beneficial effect that technical scheme brought is:

the sand washing joint in the embodiment of the utility model is provided with an upper joint and a central pipe which are coaxially connected, wherein, a buckle barrel and a conical surface ring are sleeved on the central pipe, a locking piece is sleeved on the upper joint and is propped against one end of the buckle barrel, when in use, the locking piece is pushed to enable the buckle barrel to be sleeved on the conical surface ring, so that the inner wall of the buckle barrel is matched with the conical surface ring, because a limiting piece can limit the axial displacement of the conical surface ring, the buckle barrel can be gradually sleeved on the conical surface ring, in the process, under the extrusion matching of the inner wall of the buckle barrel and the conical surface ring, the outer diameter of the buckle barrel which is divided into at least two sections by an open slot can be expanded, thereby the annular bulge can be clamped with the internal thread on the inner wall of the oil pipe after entering the oil pipe, so that the sand washing joint is rapidly clamped on the oil pipe, the sand washing joint simplifies the connection mode of, the union joint and the sand washing tool are screwed down without using tools such as pipe tongs and the like, so that the time spent in the connection process is saved, and the sand washing efficiency is improved.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.

Fig. 1 is a schematic structural diagram of a sand washing joint provided by an embodiment of the present invention;

fig. 2 is a schematic diagram of a structure diagram of a buckle barrel according to an embodiment of the present invention;

fig. 3 is a schematic structural diagram of a sand washing joint provided by an embodiment of the present invention;

fig. 4 is a schematic structural view of a locking handle according to an embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention clearer, embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

Fig. 1 is a schematic structural diagram of a sand washing joint provided by an embodiment of the present invention. As shown in fig. 1, the sand wash joint comprises: the pipe joint comprises an upper joint 1, a central pipe 2, a buckling barrel 3, a conical surface ring 4 and a locking piece 5 installed on the upper joint 1.

Wherein, the central tube 2 is coaxially connected with the upper joint 1, the central tube 2 has a first end 21 and a second end 22 which are opposite, the upper joint 1 is positioned at the first end 21, and the second end 22 has a limiting member 23. A buckle section of thick bamboo 3 slip suit is on center tube 2, be equipped with a plurality of annular archs 31 that are used for with the internal thread joint on the oil pipe inner wall on the outer wall of a buckle section of thick bamboo 3, is equipped with two at least axially extended open slots 30 on the terminal surface that a buckle section of thick bamboo 3 is close to second end 22. Conical surface ring 4, the suit is on center tube 2, is located between first end 21 and locating part 23, and from conical surface ring 4 one end that is close to first end 21 to conical surface ring 4 one end that is close to second end 22, the external diameter of conical surface ring 4 increases gradually, and conical surface ring 4 cartridge is in a buckle section of thick bamboo 3, and the outer wall of conical surface ring 4 contacts with the inner wall of a buckle section of thick bamboo 3. The locking piece 5 is pressed against one end of the buckle barrel 3.

The sand washing joint in the embodiment of the utility model is provided with an upper joint and a central pipe which are coaxially connected, wherein, a buckle barrel and a conical surface ring are sleeved on the central pipe, a locking piece is sleeved on the upper joint and is propped against one end of the buckle barrel, when in use, the locking piece is pushed to enable the buckle barrel to be sleeved on the conical surface ring, so that the inner wall of the buckle barrel is matched with the conical surface ring, because a limiting piece can limit the axial displacement of the conical surface ring, the buckle barrel can be gradually sleeved on the conical surface ring, in the process, under the extrusion matching of the inner wall of the buckle barrel and the conical surface ring, the outer diameter of the buckle barrel which is divided into at least two sections by an open slot can be expanded, thereby the annular bulge can be clamped with the internal thread on the inner wall of the oil pipe after entering the oil pipe, so that the sand washing joint is rapidly clamped on the oil pipe, the sand washing joint simplifies the connection mode of, the union joint and the sand washing tool are screwed down without using tools such as pipe tongs and the like, so that the time spent in the connection process is saved, and the sand washing efficiency is improved.

In the present embodiment, the cross section of the annular protrusion 31 on the outer wall of the latch barrel 3 in the radial direction of the latch barrel 3 may be serrated (see fig. 1). Correspondingly, the clamping groove matched with the annular protrusion 31 in the oil pipe can also be a serrated groove, and the serrated annular protrusion 31 is matched with the clamping groove, so that the oil pipe and the buckle barrel 3 can be prevented from being easily separated, and the clamping reliability of the buckle barrel 3 and the oil pipe is improved.

Fig. 2 is a schematic structural diagram of a buckle barrel according to an embodiment of the present invention. As shown in fig. 2, the distance L between the two opposing slot walls 33 of the open slot 30 decreases from the slot 34 of the open slot 30 to the slot bottom 35 of the open slot 30. In this embodiment, the opening groove 30 is a through groove that runs through the inner wall and the outer wall of the buckle barrel 3, and therefore, the opening groove 30 that extends axially at least through two of the buckle barrel 3 can make the buckle barrel 3 form a multi-petal structure, so that the outer diameter of the buckle barrel 3 can be expanded outwards sufficiently, and the annular protrusion 31 is clamped in the oil pipe. Meanwhile, in the present embodiment, the distance between the two opposite groove walls 33 on the opening groove 30 gradually decreases from the end of the latch barrel 3 close to the second end to the end of the latch barrel 3 close to the first end. As shown in fig. 2, the opening groove 30 is triangular, and the distance between the two groove walls 33 of the end of the buckle cylinder 3 close to the second end is larger in the triangular opening groove 30, so that the area of the buckle cylinder 3 close to the second end is more easily deformed, the outer diameter of the buckle cylinder 3 is easier to expand, and the distance between the two groove walls 33 of the buckle cylinder 3 is gradually reduced in the direction from the second end to the first end, so that the area of the buckle cylinder 3 close to the first end has enough strength to prevent the buckle cylinder 3 with a multi-petal structure from being easily broken. Meanwhile, the triangular open slot 30 can ensure that the buckle barrel 3 has enough contact area with the oil pipe, so that the stability of the buckle barrel 3 after being clamped and connected with the oil pipe is ensured.

The first type is that the buckle cylinder moves towards the second end, and the buckle cylinder is sleeved on the conical surface ring at the moment; the second is that the cartridge moves toward the first end, at which time the cartridge disengages the conical ring.

In the first state, when the buckle barrel 3 gradually moves towards the second end 22, the diameter of the buckle barrel 2 matched with the conical surface ring 4 gradually increases, so that the multi-petal structure of the buckle barrel 3 gradually expands outwards, and the annular bulge 31 of the buckle barrel 3 can be tightly clamped with the internal thread of the oil pipe; under the second state, when a buckle section of thick bamboo 3 removed to first end 21 gradually, a buckle section of thick bamboo 2 diminishes with conical surface ring 3 complex diameter gradually, makes a buckle section of thick bamboo 3's multi-petal structure retrieve gradually to the annular bulge 31 that makes a buckle section of thick bamboo 3 breaks away from with the internal thread of oil pipe, separates with oil pipe until a buckle section of thick bamboo 3.

As shown in fig. 1, the inner wall surface of the catch barrel 3 that engages with the conical ring 4 has a projection 32 extending in the radial direction of the catch barrel 3. Thus, when the fastening cylinder 3 is sleeved on the conical ring 4, the protrusion 32 on the inner wall of the fastening cylinder 3 is abutted against the conical ring 4. As the cartridge 3 is gradually moved toward the second end 22, the force exerted on the protrusions by the conical ring 4 is increased, thereby pushing the protrusions 32 to cause the multi-lobed structure of the cartridge to expand radially outward, i.e., to achieve the purpose of changing the diameter of the cartridge 3

Alternatively, the protrusion 32 may be a ring-shaped protrusion arranged along the circumferential direction of the inner wall of the buckle barrel 3, or a plurality of protrusions distributed along the circumferential direction of the inner wall of the buckle barrel 3. Like this when buckle section of thick bamboo 3 and conical surface ring 4 offset, conical surface ring 4 can provide even effort to buckle section of thick bamboo 3 to guarantee that buckle section of thick bamboo 3 diameter can alternate uniformly.

Exemplarily, as shown in fig. 1, the protrusion 32 is a ring-shaped protrusion arranged along the circumferential direction of the inner wall of the snap cylinder 3. And the protrusion 32 is in a sharp angle shape, that is, the inner diameter of the buckle barrel 3 is gradually reduced from the two ends of the buckle barrel 3 to the middle portion. Therefore, the inner diameters of the two ends of the buckle barrel 3 are larger, so that the buckle barrel 3 can be easily sleeved on the conical surface ring 4, and the use is convenient. When such a protrusion 32 is machined, a machining tool (milling cutter) may be used to gradually mill the inner wall of the clip cylinder 3 from both ends of the clip cylinder 3 toward the middle. In order to prevent the protrusion 32 from scratching the conical ring 4 during sliding, the protrusion 32 may be machined into an arc shape.

Optionally, the snap cylinder 3 is a spring steel structure. That is, the snap cylinder 3 may be a structural member made of spring steel. Spring steel is a steel material used for manufacturing springs and elastic elements. This kind of steel has good elastic deformation ability, therefore uses the buckle section of thick bamboo 3 of spring steel preparation to be difficult to appear permanent deformation at the in-process that uses, and stability is high, long service life.

Alternatively, the stopper 21 at the other end of the center tube 2 may be a nut. The nut is connected with the screw-thread fit of 2 second end positions of center tube to fix the nut at the second end of center tube 2, when conical surface ring 4 offseted with the nut, can restrict conical surface ring 4 and slide to the second end of center tube 2, the conical surface ring 4 of being convenient for cooperates with a buckle section of thick bamboo 3, also prevents that conical surface ring 4 from landing on center tube 2.

Optionally, the sand flushing joint may further include an annular rubber hose 6, the annular rubber hose 6 is sleeved in the central tube 2, and the annular rubber hose 6 is located between the conical surface ring 4 and the limiting member 21. In this embodiment, after the annular rubber tube 6 is sleeved on the central tube 2, two sides of the annular rubber tube 6 respectively abut against the conical surface ring 4 and the limiting part 21, so that after the conical surface ring 4 is pushed by the buckle barrel 3, the annular rubber tube 6 is extruded to deform the annular rubber tube 6, and the radial size of the deformed annular rubber tube 6 can be tightly attached to the inner wall of the oil tube, so that the oil tube is sealed, the sand flushing liquid is prevented from leaking from the joint of the buckle barrel 3 and the oil tube, and the sealing performance of the sand flushing joint after installation and connection is improved.

In this embodiment, there may be a plurality of annular rubber hoses 6, and an annular partition 7 sleeved on the central tube 2 is disposed between two adjacent annular rubber hoses 6. Illustratively, as shown in fig. 1, there may be three annular rubber hoses 6 and three annular partition plates 7, and the annular rubber hoses 6 and the annular partition plates 7 are sequentially sleeved on the central pipe 2 at intervals. The annular partition plates 7 are arranged between the annular rubber tubes 6, so that when the annular rubber tubes 6 are mutually extruded, acting force is transmitted through the annular partition plates 7, and the annular partition plates 7 are in planar contact with the annular rubber tubes 6, so that the annular rubber tubes 6 are stressed more uniformly.

In this embodiment, the lock member 5 is used to restrict the latch barrel 3 to any position on the upper joint 1. That is, after the locking cylinder 3 is adjusted to a proper position, it can be fixed on the upper joint 1 through the locking member 5.

In a possible embodiment, as shown in fig. 3, the locking member 5 includes a locking sleeve plate 51 and two locking handles 52, the locking sleeve plate 51 is fixedly sleeved on the upper joint 1, two side plates 53 extending along the axial direction of the upper joint 1 are provided on the locking sleeve plate 51, the two side plates 53 are arranged in parallel and oppositely, a plurality of pin holes 54 are uniformly distributed on the two side plates 53 along the axial direction of the upper joint 1, the two locking handles 52 are both located between the two side plates 53, a pin shaft matching with the pin hole 54 is provided on the two locking handles 52, and both the two locking handles 52 are inserted on the two side plates 53 through the pin shaft. During the use, can take out the round pin axle on the locking handle, combine figure 3, press the locking handle downwards, make the locking handle promote a buckle section of thick bamboo 3 suit gradually on conical surface ring 4, treat that a buckle section of thick bamboo 3 clamps in the oil pipe and when not having not hard up the condition, use round pin axle reconnection locking handle and curb plate to restriction buckle section of thick bamboo 3 upwards removes.

In another possible embodiment, with reference to fig. 3 and 4, the locking member 5 includes a locking sleeve plate 51 and two locking handles 52, the locking sleeve plate 51 is fixedly sleeved on the upper joint 1, the locking sleeve plate 51 is provided with two side plates 53 extending along the axial direction of the upper joint 1, the two side plates 53 are arranged in parallel and oppositely, the two side plates 53 are provided with pin holes 54 coaxially distributed, the two locking handles 52 are rotatably mounted on the side plates 53 through a pin shaft, the two locking handles have curved adjustment surfaces 55 abutting against the buckle barrel 3, and the distance between the curved adjustment surfaces 55 and the center line of the pin shaft gradually changes. In this embodiment, as shown in fig. 4, when the locking handle is rotated clockwise, the distance between the adjustment curved surface 55 and the center line of the pin gradually increases. During the use, can rotate two locking handles 52 clockwise, because the adjustment curved surface of locking handle 52 offsets with a buckle section of thick bamboo 3, consequently, at the pivoted in-process, a buckle section of thick bamboo 3 can keep away from locking handle 52 gradually, combines fig. 3, and a buckle section of thick bamboo 3 can move down gradually promptly to suit gradually on conical surface ring 4, until a buckle section of thick bamboo 3 clamps in the oil pipe and when not having the not hard up condition, stop to rotate locking handle 52, with a buckle section of thick bamboo 3 restriction on top connection 1.

In other embodiments, the distance between the adjusting curved surface and the central line of the pin shaft can be gradually reduced when the locking handle is rotated in a clockwise direction. When the locking handle is used for clamping the buckle barrel in the oil pipe, the locking handle is rotated anticlockwise.

Use the embodiment of the utility model provides a pair of sand washing connects when being connected with oil pipe, with the center tube cartridge in the oil pipe, the other end of top connection can be connected like the drilling rod through screw hole and sand washing instrument, the simultaneous control locking piece makes a buckle section of thick bamboo move down, make a buckle section of thick bamboo suit on the conical surface ring, thereby make the external diameter increase of a buckle section of thick bamboo lock with the fluting cooperation in the oil pipe under the extrusion of conical surface ring, and the conical surface ring also can extrude annular rubber tube, make annular rubber tube warp with the clearance between sealed oil pipe and the center tube.

Use the embodiment of the utility model provides a pair of during sand washing connects and oil pipe separation, control lock piece makes lock piece and a buckle section of thick bamboo separation, a buckle section of thick bamboo is under the effect of conical surface ring sum annular rubber tube elastic recovery power, axial rebound along the center tube, because a buckle section of thick bamboo separates with conical surface ring gradually, consequently, the inner wall of a buckle section of thick bamboo and the mutual effort between the conical surface ring reduce gradually, make the external diameter of a buckle section of thick bamboo reduce, thereby make a buckle section of thick bamboo and oil pipe's draw-in groove separation, directly take out sand washing joint from oil pipe this moment and can accomplish sand washing and connect and oil pipe separation.

The embodiment of the utility model provides a sand washing device, this sand washing device include the preceding sand washing joint.

The above description is only for the preferred embodiment of the present invention, and should not be construed as limiting the present invention, and any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention should be included within the protection scope of the present invention.

Claims (10)

1. A sand wash joint, comprising:

an upper joint (1);

a central tube (2) coaxially connected to the upper joint (1), the central tube (2) having opposite first and second ends (21, 22), the upper joint (1) being located at the first end (21), the second end (22) having a stop (23);

the clamping cylinder (3) is sleeved on the central pipe (2) in a sliding mode, a plurality of annular bulges (31) used for being clamped with internal threads on the inner wall of the oil pipe are arranged on the outer wall of the clamping cylinder (3), and at least two axially extending open grooves (30) are formed in the end face, close to the second end (22), of the clamping cylinder (3);

the conical surface ring (4) is sleeved on the central tube (2) and located between the first end (21) and the limiting piece (23), the outer diameter of the conical surface ring (4) is gradually increased from one end, close to the first end (21), of the conical surface ring (4) to one end, close to the second end (22), of the conical surface ring (4), the conical surface ring (4) is inserted into the buckling barrel (3), and the outer wall of the conical surface ring (4) is in contact with the inner wall of the buckling barrel (3);

and the locking piece (5) is arranged on the upper joint (1) and is abutted against one end of the buckle barrel (3).

2. A sand wash joint according to claim 1, characterized in that the distance (L) between two opposite groove walls (33) on the open groove (30) decreases from the notch (34) of the open groove (30) to the groove bottom (35) of the open groove (30).

3. A sand flush joint according to claim 1, further comprising an annular rubber hose (6), the annular rubber hose (6) being fitted around the central tube (2), the annular rubber hose (6) being located between the conical ring (4) and the retainer (23).

4. A sand flushing joint according to claim 3, characterized in that a plurality of annular rubber hoses (6) are provided, and an annular partition plate (7) sleeved on the central pipe (2) is arranged between two adjacent annular rubber hoses (6).

5. The sand washing joint according to any one of claims 1 to 4, wherein the locking member (5) comprises a locking sleeve plate (51) and two locking handles (52), the locking sleeve plate (51) is fixedly sleeved on the upper joint (1), two side plates (53) extending along the axial direction of the upper joint (1) are arranged on the locking sleeve plate (51), the two side plates (53) are oppositely arranged in parallel, a plurality of pin holes (54) are respectively distributed on the two side plates (53) along the axial direction of the upper joint (1), pin shafts matched with the pin holes (54) are arranged on the two locking handles (52), and the two locking handles (52) are inserted on the two side plates (53) through the pin shafts.

6. A sand washing joint according to any one of claims 1 to 4, wherein the locking member (5) comprises a locking sleeve plate (51) and two locking handles (52), the locking sleeve plate (51) is fixedly sleeved on the upper joint (1), two side plates (53) extending axially along the upper joint (1) are arranged on the locking sleeve plate (51), the two side plates (53) are arranged in parallel and oppositely, coaxially distributed pin holes (54) are formed in the two side plates (53), the two locking handles (52) are rotatably mounted on the side plates (53) through a pin shaft, the two locking handles (52) are provided with adjusting curved surfaces (55) abutting against the buckling cylinder (3), and the distance between the adjusting curved surfaces (55) and the center line of the pin shaft is gradually changed.

7. A sand wash joint according to any one of claims 1-4, characterized in that the inner wall surface of the catch barrel (3) cooperating with the conical ring (4) has a projection (32) extending in the radial direction of the catch barrel (3).

8. A sand wash joint according to any one of claims 1-4, wherein the snap cylinder (3) is a spring steel structure.

9. A sand wash joint according to any one of claims 1-4, wherein the retainer (23) is a nut.

10. A sand washing device characterised in that it includes a sand washing sub as claimed in any one of claims 1 to 9.

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