Integrated central cable passing device for coal mine and processing method

Abstract

The invention discloses an integrated center cable passing device for a coal mine and a machining method. The integrated center cable passing device comprises a taper hole steel connector, a copper pipe, a column hole steel connector, an insulator, a positioning steel connector, a variable-diameter spring and a center supporting body. The integrated center cable passing device is coaxially arranged in the drill rod body through the auxiliary supporting tool. According to the invention, the size of the plastic joint of the cable passing device is reasonably reduced, the overall annular open area of the drill rod is increased, the flow of flushing fluid is increased, and drilling construction and powder discharge are facilitated; the drill rod is processed and formed through the injection molding technology, and the purposes of improving the connection strength of the plastic connector and the production efficiency of the center cable passing device, reducing the machining procedures before the drill rod is assembled and reducing the machining cost are achieved.

Description

Technical Field

[0001] The invention relates to an integrated central cable passing device for coal mines and a processing method thereof. Background Art

[0002] Wired measurement while drilling system is more and more widely used in coal mines due to its advantages of simple device, convenient operation, high measurement efficiency and strong reliability. The wired measurement while drilling system for coal mines usually adopts the central cable type measurement while drilling drill pipe, which has a high data transmission rate and can realize the two-way, real-time, high-speed and stable transmission of power and signals between the wellhead and the bottom of the well.

[0003] The existing center-through cable type MWD drill pipe has the following two problems:

[0004] The center stabilizer and support device of the drill pipe together occupy about 12% of the flow area of ​​the inner hole of the drill pipe body, reducing the effective flow area of ​​the inner hole; the stabilizer occupies about 75% of the axial inner hole length of the drill pipe, increasing the fluid friction resistance. Ultimately, the two lead to increased loss of drilling fluid pressure along the hole. At the same time, the flow rate of flushing fluid is reduced, which can easily cause insufficient downhole power.

[0005] The commonly used center cable-type measurement while drilling drill pipe center cable device is assembled from multiple parts and has multiple connection points where the seals are prone to fail. The commonly used drill pipe length is 3m. The center cable device is installed in the drill pipe body with hard supports at both ends and soft supports in the middle. During drilling, the cable device is prone to deflection under the action of rotating centrifugal force and deadweight, which accelerates the failure of the sealing part and causes signal transmission interruption to occur frequently, affecting the construction progress. Summary of the invention

[0006] In view of the deficiencies in the prior art, the purpose of the present invention is to provide an integrated center cable device and a processing method for coal mines, which solves the problem that the existing center cable type downhole measurement drill rod occupies a large flow area, resulting in increased pressure loss of drilling fluid circulation in the hole and reduced flushing fluid flow, causing insufficient downhole power and poor powder discharge; improves the signal transmission reliability of the center cable device; reduces the number of manual installation process links in the drill rod assembly process, reduces the labor intensity of workers, and saves labor costs; improves the applicability of the center cable drill rod and the production efficiency of the center cable device, shortens the processing cycle, and reduces manufacturing costs.

[0007] In order to solve the above technical problems, the present invention adopts the following technical solutions to achieve the above problems:

[0008] An integrated central cable-passing device for coal mines, comprising a tapered hole steel joint, a copper tube, a column hole steel joint, an insulator, a positioning steel joint, a variable diameter spring, and a central support body;

[0009] The tapered hole steel joint and the column hole steel joint are arranged at both ends of the copper tube and are coaxially fixed and welded together; the insulator is wrapped around the tapered hole steel joint, the copper tube and the column hole steel joint to form an integrated injection molded body; the positioning steel joint is arranged outside the insulator and is wrapped around the insulator and is coaxial, the insulator wraps the positioning steel joint in the axial direction, and the positioning steel joint wraps the insulator in the circumferential direction; the variable diameter spring is assembled in the column hole steel joint, and together with the column hole steel joint, the copper tube and the tapered hole steel joint, it forms a conduction module of the center cable device; the center support body is sleeved in the middle position outside the insulator and supported on the inner wall of the drill pipe, so that the integrated center cable device is effectively supported inside the drill pipe.

[0010] The present invention also includes the following technical features:

[0011] Specifically, the inner hole of the positioning steel joint is provided with a spiral groove, and the side surface is provided with a rectangular groove or a circular hole.

[0012] Specifically, both ends of the insulator are plug-in connectors, one end is an external connector with two sealing grooves, and the other end is an internal connector with a smooth cylindrical hole.

[0013] Specifically, the end face of the inner joint of the insulator is an end face open groove.

[0014] Specifically, the two axial ends of the central support body are circular rings and can be sleeved in the middle position outside the insulator. A three-wing or four-wing arch or cone-cylinder-cone three-section structure is connected between the two circular rings and supported in the annulus between the inner wall of the drill pipe and the insulator. The material is spring steel, so that it has sufficient deformation margin during installation, so that it can fully enter the pipe body hole through the small hole at the end of the drill pipe and then rebound to the size of the inner hole of the pipe body, and has sufficient rigidity to resist the centrifugal force borne by the central cable device during drilling.

[0015] An integrated center cable passing device and a matching drill rod, comprising the integrated center cable passing device, a drill rod body, and also comprising auxiliary supporting tooling: a shaft retaining spring, an inclined surface limit support ring, a hole retaining spring I, a hole retaining spring II, a straight surface limit support ring, a compression spring, and an O-ring; the drill rod body comprises a drill rod internal thread joint, a drill rod tube body, and a drill rod external thread joint that are coaxial and welded in sequence; the integrated center cable passing device is coaxially arranged in the drill rod body, and is supported in the drill rod body and positioned axially by the hole retaining spring I, the shaft retaining spring, the inclined surface limit support ring, the hole retaining spring II, the straight surface limit support ring, and the compression spring.

[0016] Specifically, the large diameter end of the inclined surface limiting support ring is supported on the hole retaining spring I on the inner wall of the drill pipe internal threaded joint, and the small diameter end is supported on the shaft retaining spring at the positioning steel joint outside the insulator; the outer ring of the straight surface limiting support ring is axially limited by the hole retaining spring II on the inner wall of the drill pipe external threaded joint, the inner ring of the straight surface limiting support ring is sleeved on the insulator, the compression spring is arranged between the inner ring of the straight surface limiting support ring and the boss on the outer wall of the joint inside the insulator, the hole retaining spring II and the compression spring are located on both sides of the straight surface limiting support ring; the O-ring is arranged in the sealing groove of the joint outside the insulator.

[0017] Specifically, when the integrated center cable device is compressed due to a sudden temperature change in the drill rod body, it can automatically compensate for the expansion and contraction amount through the pre-compression of the compression spring to meet the use requirements of the drill rod.

[0018] The processing method of the integrated central cable passing device adopts one-step injection molding, and comprises the following steps:

[0019] Step 1: Processing the integrated central cable-passing device and auxiliary support tooling;

[0020] Step 2: Install the auxiliary support tooling on the welded body composed of the tapered hole steel joint, the copper tube and the column hole steel joint and place it in the mold;

[0021] Step 3: Use high impact PP and reinforced PP in a ratio of 10:3 for injection molding, injection pressure 40MPa, injection temperature 200℃ for zone 1, 210℃ for zone 2, 210℃ for zone 3, 200℃ for zone 4, injection speeds 25mm / min for zone 1, 12mm / min for zone 2, 30mm / min for zone 3, 25mm / min for zone 4, holding pressure 45MPa, holding time 10 seconds, cooling time 3 minutes, demoulding and taking out the integrated central cable device;

[0022] Step 4: The integrated center cable device is finely processed to the required size.

[0023] The processing method of the integrated central cable-passing device adopts step-by-step injection molding, and comprises the following steps:

[0024] Step 1: respectively process the outer joint side mold of the insulator of the integrated central cable-through device, the inner joint side mold of the insulator and the auxiliary support tooling;

[0025] Step 2: Install auxiliary support tooling on the welded body composed of the tapered hole steel joint, the copper tube and the column hole steel joint and place it in the mold;

[0026] Step 3: Use high impact PP and reinforced PP in a ratio of 10:3 to perform injection molding of the middle part of the integrated central cable device, with an injection pressure of 40 MPa, a temperature of 200°C, a speed of 20 mm / min, a holding pressure of 40 MPa, a holding time of 10 seconds, a cooling time of 1 minute, and demolding;

[0027] Step 4: Use high-impact PP and reinforced PP in a ratio of 10:3 to perform injection molding on the outer joint side of the insulator of the integrated central cable device, with an injection pressure of 40 MPa, a temperature of 200°C, a speed of 20 mm / min, a holding pressure of 45 MPa, a holding time of 10 seconds, a cooling time of 2 minutes, and demolding;

[0028] Step 5: Use high-impact PP and reinforced PP in a ratio of 10:3 to perform injection molding on the inner joint side of the insulator of the integrated central cable device, with an injection pressure of 40 MPa, a temperature of 200°C, a speed of 20 mm / min, a holding pressure of 45 MPa, a holding time of 10 seconds, a cooling time of 2 minutes, and demolding;

[0029] Step 6: The integrated center cable device is finely processed to the required size.

[0030] Compared with the prior art, the present invention has the following technical effects:

[0031] The present invention reasonably reduces the size of the plastic joint of the center cable device, increases the overall flow area of ​​the drill pipe annulus, promotes the increase of the flushing fluid flow rate, and is beneficial to drilling construction and powder removal; the center cable device is processed and formed by the injection molding process, thereby achieving the goals of improving the connection strength of the plastic joint and the production efficiency of the center cable device, reducing the processing steps before drill pipe assembly, and reducing the processing cost; effectively improves the applicability and reliability of the center cable drill pipe for while-drilling measurement in coal mines, shortens the processing cycle, and reduces the manufacturing cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic diagram of the injection molding structure of the integrated while-drilling measurement center cable device for coal mines of the present invention.

[0033] Figure 2 This is a schematic diagram of the drill pipe assembly structure of the integrated while-drilling measurement center cable device for coal mines.

[0034] Figure 3 Schematic diagram of the central support structure.

[0035] The meaning of each number in the figure is:

[0036] 1-conical hole steel joint, 2-positioning steel joint, 3-copper tube, 4-column hole steel joint, 5-insulator, 6-O-ring, 7-shaft retaining spring, 8-inclined surface limit support ring, 9-hole retaining spring I, 10-drill pipe internal thread joint, 11-drill pipe body, 12-center support body, 13-drill pipe external thread joint, 14-hole retaining spring II, 15-straight surface limit support ring, 16-compression spring, 17-variable spring. DETAILED DESCRIPTION

[0037] Specific embodiments of the present invention are given below. It should be noted that the present invention is not limited to the following specific embodiments, and all equivalent changes made on the basis of the technical solution of this application fall within the protection scope of the present invention.

[0038] Embodiment 1:

[0039] like Figures 1 to 3 As shown, this embodiment provides an integrated center cable device for coal mines, including a tapered hole steel joint 1, a copper tube 3, a column hole steel joint 4, an insulator 5, a positioning steel joint 2, a variable diameter spring 17, and a center support body 12.

[0040] The tapered hole steel joint 1 and the column hole steel joint 4 are arranged at both ends of the copper tube 3 and are coaxially fixed and welded together; the insulator 5 is wrapped around the tapered hole steel joint 1, the copper tube 3 and the column hole steel joint 4 to form an integrated injection molding body; the positioning steel joint 2 is arranged outside the insulator 5 and is coaxial with the insulator 5, the insulator 5 wraps the positioning steel joint 2 in the axial direction, and the positioning steel joint 2 wraps the insulator 5 in the circumferential direction; the variable diameter spring 17 is assembled in the column hole steel joint 4, and together with the column hole steel joint 4, the copper tube 3 and the tapered hole steel joint 1, it forms a conduction module of the center cable device; the center support body 12 is sleeved in the middle position outside the insulator 5 and supported on the inner wall of the drill pipe, so that the integrated downhole measurement center cable device is effectively supported inside the drill pipe.

[0041] The inner hole of the positioning steel joint 2 is provided with a spiral groove, and the side surface is provided with a rectangular groove or a circular hole.

[0042] The two ends of the insulator 5 are plug-in connectors, one end is an external connector with two sealing grooves, and the other end is an internal connector with a smooth cylindrical hole, which has a sealing effect.

[0043] The end face of the inner joint of the insulator 5 is an end face opening groove, so as to be used in conjunction with a special tool during assembly to prevent the central cable passing device from rotating.

[0044] The central support body 12 has circular rings at both axial ends and can be sleeved in the middle position outside the insulator 5. A three-wing or four-wing arch or cone-cylinder-cone three-section structure is connected between the two circular rings and supported in the annulus between the inner wall of the drill pipe and the insulator 5. The material is spring steel, so that it has sufficient deformation margin during installation, so that it can fully enter the pipe body hole through the small hole at the end of the drill pipe and then rebound to the size of the inner hole of the pipe body, and has sufficient rigidity to resist the centrifugal force borne by the central cable device during drilling.

[0045] The present invention also provides an integrated center cable device and a matching drill rod, comprising the above-mentioned integrated center cable device, a drill rod body, and an auxiliary support tooling: a shaft retaining spring 7, an inclined surface limit support ring 8, a hole retaining spring I 9, a hole retaining spring II 14, a straight surface limit support ring 15, a compression spring 16, and an O-ring 6; the drill rod body comprises a drill rod internal thread joint 10, a drill rod tube body 11, and a drill rod external thread joint 13 which are coaxially and welded in sequence, and the inner burr is turned to make the inner hole of the drill rod smooth and round without any abnormal protrusions; the integrated center cable device is coaxially arranged in the drill rod body, and is supported in the drill rod body and positioned in the axial direction by the hole retaining spring I 9, the shaft retaining spring 7, the inclined surface limit support ring 8, the hole retaining spring II 14, the straight surface limit support ring 15, and the compression spring 16. The limit support ring structure is but not limited to a cylindrical structure, a conical structure, etc. The compression spring 16 is but not limited to a wave spring, a disc spring, etc.

[0046] The large diameter end of the inclined surface limiting support ring 8 is supported on the hole retaining spring I9 on the inner wall of the drill pipe internal threaded joint 10, and the small diameter end is supported on the shaft retaining spring 7 at the positioning steel joint 2 outside the insulator 5; the inclined surface limiting support ring 8 does not affect the axial penetration inside the drill pipe body; the outer ring of the straight surface limiting support ring 15 is axially limited by the hole retaining spring II14 on the inner wall of the drill pipe external threaded joint 13, the inner ring of the straight surface limiting support ring 15 is sleeved on the outside of the insulator 5, and the compression spring 16 is arranged between the inner ring of the straight surface limiting support ring 15 and the outer wall boss of the inner joint of the insulator 5, and the hole retaining spring II14 and the compression spring 16 are located on both sides of the straight surface limiting support ring 15; the straight surface limiting support ring 15 does not affect the axial penetration inside the drill pipe body; the O-ring 6 is arranged in the sealing groove of the outer joint of the insulator 5.

[0047] When the integrated central cable device is compressed due to a sudden temperature change in the drill rod body, it can automatically compensate for the expansion and contraction amount through the pre-compression of the compression spring 16 to meet the use requirements of the drill rod.

[0048] The present invention provides a processing method for an integrated central cable-passing device, which adopts one-step injection molding and comprises the following steps:

[0049] Step 1: Processing the integrated central cable-passing device and auxiliary support tooling;

[0050] Step 2: Install the auxiliary support tooling on the welded body composed of the tapered hole steel joint, the copper tube and the column hole steel joint and place it in the mold;

[0051] Step 3: Use high impact PP and reinforced PP in a ratio of 10:3 for injection molding, injection pressure 40MPa, injection temperature 200℃ for zone 1, 210℃ for zone 2, 210℃ for zone 3, 200℃ for zone 4, injection speeds 25mm / min for zone 1, 12mm / min for zone 2, 30mm / min for zone 3, 25mm / min for zone 4, holding pressure 45MPa, holding time 10 seconds, cooling time 3 minutes, demoulding and taking out the integrated central cable device;

[0052] Step 4: The integrated center cable device is finely processed to the required size.

[0053] The present invention also provides another method for processing an integrated central cable passing device, which adopts step-by-step injection molding and includes the following steps:

[0054] Step 1: respectively process the outer joint side mold of the insulator of the integrated central cable-through device, the inner joint side mold of the insulator and the auxiliary support tooling;

[0055] Step 2: Install auxiliary support tooling on the welded body composed of the tapered hole steel joint, the copper tube and the column hole steel joint and place it in the mold;

[0056] Step 3: Use high impact PP and reinforced PP in a ratio of 10:3 to perform injection molding of the middle part of the integrated central cable device, with an injection pressure of 40 MPa, a temperature of 200°C, a speed of 20 mm / min, a holding pressure of 40 MPa, a holding time of 10 seconds, a cooling time of 1 minute, and demolding;

[0057] Step 4: Use high-impact PP and reinforced PP in a ratio of 10:3 to perform injection molding on the outer joint side of the insulator of the integrated central cable device, with an injection pressure of 40 MPa, a temperature of 200°C, a speed of 20 mm / min, a holding pressure of 45 MPa, a holding time of 10 seconds, a cooling time of 2 minutes, and demolding;

[0058] Step 5: Use high-impact PP and reinforced PP in a ratio of 10:3 to perform injection molding on the inner joint side of the insulator of the integrated central cable device, with an injection pressure of 40 MPa, a temperature of 200°C, a speed of 20 mm / min, a holding pressure of 45 MPa, a holding time of 10 seconds, a cooling time of 2 minutes, and demolding;

[0059] Step 6: The integrated MWD center cable device is finely processed to the required size.

[0060] Steps 4 and 5 are interchangeable.

[0061] The preferred embodiments of the present invention are described in detail above in conjunction with the accompanying drawings. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0062] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0063] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. An integrated central cable device for coal mines, characterized in that: It comprises a tapered hole steel joint (1), a copper tube (3), a column hole steel joint (4), an insulator (5), a positioning steel joint (2), a variable diameter spring (17), and a central support body (12); The tapered hole steel joint (1) and the column hole steel joint (4) are arranged at both ends of the copper tube (3) and are coaxially fixed and welded together; the insulator (5) is wrapped around the tapered hole steel joint (1), the copper tube (3) and the column hole steel joint (4) to form an integrated injection molded body; the positioning steel joint (2) is arranged outside the insulator (5) and is mutually wrapped and coaxial with the insulator (5), the insulator (5) wraps around the positioning steel joint (2) in the axial direction, and the positioning steel joint (2) wraps around the insulator (5) in the circumferential direction; the variable diameter spring (17) is assembled in the column hole steel joint (4), and together with the column hole steel joint (4), the copper tube (3) and the tapered hole steel joint (1) form a conduction module of the central cable device; the central support body (12) is sleeved in the middle position outside the insulator (5) and supported on the inner wall of the drill pipe, so that the integrated central cable device is effectively supported inside the drill pipe.

2. The integrated center cable device for coal mines according to claim 1, characterized in that: The inner hole of the positioning steel joint (2) is provided with a spiral groove, and the side surface is provided with a rectangular groove or a circular hole.

3. The integrated center cable device for coal mines according to claim 1, characterized in that: The insulator (5) has plug-in connectors at both ends, one end is an external connector with two sealing grooves, and the other end is an internal connector with a smooth cylindrical hole.

4. The integrated center cable device for coal mines according to claim 3, characterized in that: The inner joint end face of the insulator (5) is an end face open groove.

5. The integrated center cable device for coal mines according to claim 1, characterized in that: The central support body (12) has circular rings at both axial ends and can be sleeved in the middle position outside the insulator (5). A three-wing or four-wing arch or cone-cylinder-cone three-section structure is connected between the two circular rings and supported in the annulus between the inner wall of the drill pipe and the insulator (5). The material is spring steel, so that it has sufficient deformation margin during installation, so that it can fully enter the pipe body hole through the small hole at the end of the drill pipe and then rebound to the size of the inner hole of the pipe body, and has sufficient rigidity to resist the centrifugal force borne by the central cable device during drilling.

6. An integrated central cable device supporting a drill pipe, characterized in that: The invention comprises an integrated center cable passing device and a drill rod body as described in any one of claims 2 to 5, and also comprises auxiliary supporting tooling: a shaft retaining spring (7), an inclined surface limit support ring (8), a hole retaining spring I (9), a hole retaining spring II (14), a straight surface limit support ring (15), a compression spring (16), and an O-ring (6); the drill rod body comprises a drill rod internal thread joint (10), a drill rod tube (11) and a drill rod external thread joint (13) which are coaxially welded in sequence; the integrated center cable passing device is coaxially arranged in the drill rod body, and is supported in the drill rod body and positioned axially by means of the hole retaining spring I (9), the shaft retaining spring (7), the inclined surface limit support ring (8), the hole retaining spring II (14), the straight surface limit support ring (15) and the compression spring (16).

7. The integrated center cable device and supporting drill rod according to claim 6, characterized in that: The large diameter end of the inclined surface limiting support ring (8) is supported on the hole retaining spring I (9) on the inner wall of the drill pipe internal threaded joint (10), and the small diameter end is supported on the shaft retaining spring (7) at the positioning steel joint (2) outside the insulator (5); the outer ring of the straight surface limiting support ring (15) is axially limited by the hole retaining spring II (14) on the inner wall of the drill pipe external threaded joint (13), the inner ring of the straight surface limiting support ring (15) is sleeved outside the insulator (5), the compression spring (16) is arranged between the inner ring of the straight surface limiting support ring (15) and the boss on the outer wall of the inner joint of the insulator (5), the hole retaining spring II (14) and the compression spring (16) are located on both sides of the straight surface limiting support ring (15); the O-ring (6) is arranged in the sealing groove of the outer joint of the insulator (5).

8. The integrated center cable device and supporting drill rod according to claim 7, characterized in that: When the integrated central cable device is compressed due to a sudden temperature change in the drill rod body, the expansion and contraction amount can be automatically compensated by pre-compression of the compression spring (16), thereby meeting the use requirements of the drill rod.

9. The processing method of the integrated central cable device according to any one of claims 2 to 5, characterized in that: The method adopts one-step injection molding and includes the following steps: Step 1: Processing the integrated central cable-passing device and auxiliary support tooling; Step 2: Install the auxiliary support tooling on the welded body composed of the tapered hole steel joint, the copper tube and the column hole steel joint and place it in the mold; Step 3: Use high impact PP and reinforced PP in a ratio of 10:3 for injection molding, injection pressure 40MPa, injection temperature 200℃ for zone 1, 210℃ for zone 2, 210℃ for zone 3, 200℃ for zone 4, injection speeds 25mm / min for zone 1, 12mm / min for zone 2, 30mm / min for zone 3, 25mm / min for zone 4, holding pressure 45MPa, holding time 10 seconds, cooling time 3 minutes, demoulding and taking out the integrated central cable device; Step 4: The integrated center cable device is finely processed to the required size.

10. The processing method of the integrated central cable device according to any one of claims 2 to 5, characterized in that: The method adopts step-by-step injection molding, comprising the following steps: Step 1: respectively process the outer joint side mold of the insulator of the integrated central cable-through device, the inner joint side mold of the insulator and the auxiliary support tooling; Step 2: Install auxiliary support tooling on the welded body composed of the tapered hole steel joint, the copper tube and the column hole steel joint and place it in the mold; Step 3: Use high impact PP and reinforced PP in a ratio of 10:3 to perform injection molding of the middle part of the integrated central cable device, with an injection pressure of 40 MPa, a temperature of 200°C, a speed of 20 mm / min, a holding pressure of 40 MPa, a holding time of 10 seconds, a cooling time of 1 minute, and demolding; Step 4: Use high-impact PP and reinforced PP in a ratio of 10:3 to perform injection molding on the outer joint side of the insulator of the integrated central cable device, with an injection pressure of 40 MPa, a temperature of 200°C, a speed of 20 mm / min, a holding pressure of 45 MPa, a holding time of 10 seconds, a cooling time of 2 minutes, and demolding; Step 5: Use high-impact PP and reinforced PP in a ratio of 10:3 to perform injection molding on the inner joint side of the insulator of the integrated central cable device, with an injection pressure of 40 MPa, a temperature of 200°C, a speed of 20 mm / min, a holding pressure of 45 MPa, a holding time of 10 seconds, a cooling time of 2 minutes, and demolding; Step 6: The integrated center cable device is finely processed to the required size.

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