Seals on field-retrofittable progressive cavity pump drives

Abstract

The sealing device on the screw pump driving device that can be modified on site relates to the technical field of oil extraction equipment, including a bearing box, a driving shaft is rotatably arranged in the bearing box, a thrust bearing and a radial bearing are arranged in sequence from top to bottom between the driving shaft and the bearing box, a sealing member sleeved on the driving shaft is arranged in the area of ​​the bearing box below the radial bearing, and the bearing box is provided with a sealing chamber with adjustable position along the vertical direction, the sealing chamber is sleeved on the driving shaft, and the upper end of the sealing chamber is against the sealing member. The present invention solves the problem that the screw pump in the traditional technology is installed at the wellhead because the ground driving device is installed, the rod column passes through the rotating shaft, and the new oil seal cannot be installed, resulting in the oil seal being unable to be replaced at the wellhead after it is broken, and it can only be hoisted away from the wellhead, but the oil well needs to be shut down for a long time, requiring a lot of equipment and a large workload.

Description

Technical Field

[0001] The invention relates to the technical field of oil production equipment, in particular to a sealing device on a screw pump driving device which can be modified on site. Background Art

[0002] Screw pumps are widely used in oilfield production. Most screw pump oil production devices are ground-driven. A device that drives the screw pump rotor to rotate needs to be installed on the ground, which is called a ground drive device. The ground drive device drives the rod column to rotate to rotate the rotor of the screw pump to produce oil. There are bearings and brake mechanisms in the ground drive device. These mechanisms need to be filled with lubricating oil in the ground drive device. If there is lubricating oil, a sealing device must be installed, otherwise the lubricating oil will leak, causing equipment damage and environmental pollution, resulting in significant economic losses.

[0003] The seal on the existing sealing device is an oil seal, which is a standard part. The fifth edition of the "Machinery Design Manual" published by the Machinery Industry Press, Volume 3, Pages 21-51, states that the service life of the oil seal is 2000 hours. However, the screw pump drive device is installed at the wellhead and needs to work for 1 to several years. Therefore, the oil seal cannot meet the sealing requirements of the existing screw pump ground drive device, resulting in oil leakage.

[0004] like Figure 1 As shown, the existing screw pump drive device includes a bearing box 100, a drive shaft 200, a thrust bearing 300, a radial bearing 400, an oil seal 500, a connecting screw 600, a base 700, and a bare rod 800. The bottom surface of the bearing box 100 has a threaded hole 900 for disassembling the bearing. The threaded hole 900 is used to disassemble the radial bearing 400 and install the screw to push it away from the bearing hole. There is lubricating oil in the bearing box 100.

[0005] As the existing technologies including the above devices are used, the shortcomings of the technologies are gradually exposed, which are mainly manifested in the following aspects:

[0006] The existing sealing structure will leak oil after a certain working time. Since the ground drive device is installed at the wellhead, the rod column is more than 1,000 meters long and passes through the rotating shaft, and the new oil seal cannot be installed in. As a result, the oil seal cannot be replaced at the wellhead after it is broken. It can only be replaced by lifting it away from the wellhead and separating it from the rod column. Although this method can replace the seal, the oil well has to be shut down for a long time, which requires a lot of equipment and a large workload.

[0007] In summary, the existing technology obviously has inconveniences and defects in practical use, so it is necessary to improve it. Summary of the invention

[0008] In view of the defects in the prior art, the present invention solves the problem that in the conventional technology, since the ground drive device of the screw pump is installed at the wellhead and the rod column passes through the rotating shaft, a new oil seal cannot be installed therein, resulting in that the oil seal cannot be replaced at the wellhead after it is broken and can only be replaced by lifting it away from the wellhead and separating it from the rod column. Although this method can replace the seal, the oil well has to be shut down for a long time, requires a lot of equipment and a large workload.

[0009] To solve the above problems, the present invention provides the following technical solutions:

[0010] The sealing device on the screw pump driving device which can be modified on site comprises a bearing box, a driving shaft is rotatably arranged in the bearing box, a polished rod is connected to the driving shaft, and a thrust bearing and a radial bearing are arranged in sequence from top to bottom between the driving shaft and the bearing box.

[0011] The area of ​​the bearing box below the radial bearing is provided with a seal mounted on the drive shaft. The bearing box is provided with a seal cavity with adjustable position vertically. The seal cavity is mounted on the drive shaft, and the upper end of the seal cavity abuts against the seal.

[0012] As an optimized solution, a sealing cavity insertion channel is axially opened on the side wall of the sealing cavity and runs through both ends thereof, and the sealing cavity is sleeved on the driving shaft along the radial direction of the polished rod through the sealing cavity insertion channel.

[0013] As an optimized solution, the sealing member comprises a polished rod sealing packing, and the sealing member is provided with a score opening along the axial direction.

[0014] As an optimized solution, a filling block is radially mounted at the upper end of the sealing cavity into the channel, and the upper end of the filling block and the upper end of the sealing cavity are respectively abutted against the lower end of the sealing member.

[0015] As an optimized solution, the sealing cavity is provided with a filling groove in the card-in channel, and the opposite side walls of the filling groove are respectively fixed with card stages, and the opposite end faces of the two card stages are arranged to taper from the outside to the center, and the opposite end faces of the filling block are provided with card grooves matching the card stages.

[0016] As an optimized solution, a retaining ring is provided in the area of ​​the bearing box above the sealing member, and the upper end of the sealing member abuts against the lower end of the retaining ring.

[0017] As an optimized solution, the retaining ring includes two semicircular rings that are butt-jointed, wherein an insertion block is fixedly connected to the butt end face of one of the semicircular rings, and an insertion groove is provided on the butt end face of the other semicircular ring.

[0018] As an optimized solution, the bearing box is fixed with a fixing bracket by means of screws, and a bracket insertion channel for avoiding the light rod is provided on a side wall of the fixing bracket.

[0019] As an optimized solution, a first internal thread is provided on the inner wall of the fixing bracket, and a first external thread matching the first internal thread is provided on the outer wall of the sealing cavity.

[0020] As an optimized solution, a locking sleeve is sleeved on the outside of the fixing bracket, a locking sleeve insertion channel for avoiding the light rod is opened on the side wall of the locking sleeve, and a limiting ring is provided at the lower end of the locking sleeve to abut against the lower end of the sealing cavity.

[0021] As an optimized solution, a second external thread is provided on the outer wall of the fixing bracket, and a second internal thread matching the second external thread is provided on the inner wall of the locking sleeve.

[0022] As an optimized solution, a plurality of threaded holes are arranged on the outer wall of the lock sleeve, and bolts are threadedly connected to the threaded holes, and the ends of the bolts are against the sealing cavity.

[0023] As an optimized solution, a disc-shaped boss is provided on the top of the fixing bracket, and a mounting hole aligned with the threaded hole of the bearing box is opened on the disc-shaped boss. The screw is inserted into the mounting hole, and the end of the screw is threadedly connected to the threaded hole of the bearing box.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] The present invention can quickly replace the sealing device on site, and can be installed on the driving device by using the existing threaded holes of the bearing box without changing the existing component structure and without removing the ground driving device from the wellhead;

[0026] During the working process, if the sealing performance of the seal is reduced, the seal can be pressed again by rotating the sealing chamber to make it sealed, and the seal can also be quickly replaced online. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following is a brief introduction to the drawings required for the specific embodiments or the description of the prior art. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn according to the actual scale.

[0028] Figure 1 It is a structural schematic diagram of the prior art;

[0029] Figure 2 It is a schematic diagram of the structure of the present invention;

[0030] Figure 3 It is a structural schematic diagram of the retaining ring of the present invention;

[0031] Figure 4 It is a structural schematic diagram of the sealing chamber of the present invention;

[0032] Figure 5 It is a structural schematic diagram of the fixing bracket of the present invention;

[0033] Figure 6 It is a structural schematic diagram of the lock sleeve of the present invention.

[0034] In the figure: 1-bearing box; 2-driving shaft; 3-thrust bearing; 4-radial bearing; 5-seal; 6-screw; 7-base; 8-naked rod; 9-threaded hole of bearing box; 10-retaining ring; 11-fixed bracket; 12-sealing chamber; 13-locking sleeve; 14-insertion block; 15-insertion slot; 16-sealing chamber insertion channel; 17-filling slot; 18-filling block; 19-card platform; 20-card slot; 21-first external thread; 22-first internal thread; 23-second external thread; 24-second internal thread; 25-bracket insertion channel; 26-disc boss; 27-mounting hole; 28-locking sleeve insertion channel; 29-limiting ring; 30-threaded hole. DETAILED DESCRIPTION

[0035] The following embodiments of the technical solution of the present invention are described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and are therefore only used as examples, and cannot be used to limit the protection scope of the present invention.

[0036] like Figures 2 to 6 As shown, the sealing device on the screw pump drive device which can be modified on site comprises a bearing box 1, a driving shaft 2 is rotatably arranged in the bearing box 1, a polished rod 8 is connected to the driving shaft 2, and a thrust bearing 3 and a radial bearing 4 are arranged in sequence from top to bottom between the driving shaft 2 and the bearing box 1.

[0037] The area of ​​the bearing box 1 below the radial bearing 4 is provided with a seal 5 which is mounted on the drive shaft 2 . The bearing box 1 is vertically provided with a seal cavity 12 which can be adjusted in position. The seal cavity 12 is mounted on the drive shaft 2 , and the upper end of the seal cavity 12 abuts against the seal 5 .

[0038] The bearing box 1 is fixed on the base 7, and the base 7 is installed on the wellhead device of the oil well.

[0039] A sealing cavity insertion channel 16 is axially opened on the side wall of the sealing cavity 12 and runs through both ends thereof, and the sealing cavity 12 is sleeved on the driving shaft 2 along the radial direction of the polished rod 8 through the sealing cavity insertion channel 16 .

[0040] The sealing member 5 comprises a polished rod sealing packing, and the sealing member 5 is provided with a scored opening along the axial direction.

[0041] A filling block 18 is radially mounted on the upper end of the sealing cavity insertion channel 16 , and the upper end of the filling block 18 and the upper end of the sealing cavity 12 respectively abut against the lower end of the sealing member 5 .

[0042] The sealing cavity card-in channel 16 is provided with a filling groove 17, and the opposite side walls of the filling groove 17 are respectively fixed with card stages 19. The opposite end faces of the two card stages 19 are gradually tapered from the outside to the center, and the opposite end faces of the filling block 18 are provided with a card groove 20 matching the card stage 19.

[0043] A retaining ring 10 is provided in the area of ​​the bearing box 1 above the sealing member 5 , and the upper end of the sealing member 5 abuts against the lower end of the retaining ring 10 .

[0044] The retaining ring 10 includes two semicircular rings that are butt-jointed, wherein an inserting block 14 is fixedly connected to the butt-jointed end surface of one of the semicircular rings, and an inserting groove 15 is provided on the butt-jointed end surface of the other semicircular ring.

[0045] The bearing box 1 is fixed with a fixing bracket 11 by means of screws 6 , and a bracket insertion channel 25 for avoiding the polished rod 8 is provided on a side wall of the fixing bracket 11 .

[0046] A first internal thread 22 is disposed on the inner wall of the fixing bracket 11 , and a first external thread 21 matching the first internal thread 22 is disposed on the outer wall of the sealing cavity 12 .

[0047] A locking sleeve 13 is sleeved on the outside of the fixed bracket 11, and a locking sleeve insertion channel 28 for avoiding the light rod 8 is opened on the side wall of the locking sleeve 13. A limiting ring 29 is provided at the lower end of the locking sleeve 13 to abut against the lower end of the sealing cavity 12. A step is provided on the outer wall of the sealing cavity 12 near the lower end, and the limiting ring 29 abuts against the step.

[0048] A second external thread 23 is disposed on the outer wall of the fixing bracket 11 , and a second internal thread 24 matching the second external thread 23 is disposed on the inner wall of the locking sleeve 13 .

[0049] A plurality of threaded holes 30 are arranged on the outer wall of the locking sleeve 13 . Bolts are connected to the threaded holes 30 . The ends of the bolts abut against the sealing cavity 12 , so as to position the locking sleeve 13 .

[0050] A disc-shaped boss 26 is provided on the top of the fixing bracket 11 , and a mounting hole 27 aligned with the threaded hole 9 of the bearing box is opened on the disc-shaped boss 26 , a screw 6 is inserted into the mounting hole 27 , and the end of the screw 6 is threadedly connected to the threaded hole 9 of the bearing box.

[0051] The working principle of this device is:

[0052] Remove on site Figure 1 After the oil seal 500 is installed, the fixing bracket 11 is connected to the lower end surface of the bearing box 1 by screws 6, and the retaining ring 10 and the sealing member 5 are placed in the annular space between the bearing box 1 and the drive shaft 2. The first external thread 21 of the sealing chamber 12 is screwed with the first internal thread 22 of the fixing bracket 11. When the sealing chamber 12 is rotated, the upper end surface thereof squeezes the sealing member 5, so that the sealing member 5 is deformed and seals the annular space between the bearing box 1 and the drive shaft 2.

[0053] Due to the presence of the polished rod 8 at the site, the retaining ring 10, the seal 5, the fixing bracket 11, and the sealing chamber 12 cannot be directly installed in place;

[0054] Therefore, the retaining ring 10 is designed as two semicircular rings, and the cylindrical tube of the sealing member 5 needs to be cut (same as the polished rod sealing packing on the pumping well);

[0055] The fixing bracket 11 is provided with a bracket insertion channel 25 in the longitudinal direction, the width of which is equal to the diameter of the polished rod 8, the upper end of the fixing bracket 11 is a disc-shaped boss 26, two mounting holes 27 are provided on the disc-shaped boss 26, and the mounting holes 27 match the bearing box threaded holes 9 on the lower end surface of the bearing box 1;

[0056] The sealing cavity 12 is cylindrical, and the inner diameter of the upper part is slightly larger than the outer diameter of the lower part of the driving shaft 2. In addition to the sealing cavity insertion channel 16 having the same diameter as the polished rod 8, a filling groove 17 is provided for placing the filling block 18, so that the top of the sealing cavity 12 is in the shape of a whole cylinder. After the first external thread 21 of the sealing cavity 12 is screwed with the first internal thread 22 of the fixing bracket 11, the outer wall of the filling block 18 will not be separated from the filling groove 17 under the limitation of the inner wall of the fixing bracket 11;

[0057] The second internal thread 24 of the locking sleeve 13 is connected to the second external thread 23 of the fixing bracket 11, which plays a locking role to prevent the connection thread between the sealing chamber 12 and the fixing bracket 11 from loosening, thereby ensuring the pressing force of the sealing chamber 12 on the sealing member 5. Similarly, due to the existence of the polished rod 8, the locking sleeve 13 also needs to be provided with a locking sleeve insertion channel 28 having a diameter equal to that of the polished rod 8;

[0058] During the operation of the present invention, if the sealing performance of the seal 5 decreases, the seal 5 can be compressed again by rotating the sealing chamber 12 to make it sealed, and the seal 5 can also be replaced online, which is also different from the existing drive device installed on the well.

[0059] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. These modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and specification of the present invention.

Claims

1. A sealing device on a screw pump drive device that can be retrofitted on site, comprising a bearing box (1), a drive shaft (2) rotatably disposed in the bearing box (1), a polished rod (8) connected to the drive shaft (2), a thrust bearing (3) and a radial bearing (4) disposed in sequence from top to bottom between the drive shaft (2) and the bearing box (1), characterized in that: The bearing box (1) is provided with a sealing member (5) sleeved on the drive shaft (2) in an area below the radial bearing (4); the bearing box (1) is provided with a sealing chamber (12) with an adjustable position in the vertical direction; the sealing chamber (12) is sleeved on the drive shaft (2), and the upper end of the sealing chamber (12) abuts against the sealing member (5); A sealing cavity insertion channel (16) is axially provided on the side wall of the sealing cavity (12) and passes through both ends thereof, and the sealing cavity (12) is sleeved on the driving shaft (2) along the radial direction of the polished rod (8) through the sealing cavity insertion channel (16); The bearing box (1) is fixed with a fixing bracket (11) by means of screws (6), and a bracket insertion channel (25) for avoiding the polished rod (8) is provided on a side wall of the fixing bracket (11); The fixing bracket (11) is provided with a locking sleeve (13) on its exterior, a locking sleeve insertion channel (28) for avoiding the light rod (8) is provided on the side wall of the locking sleeve (13), and a limiting ring (29) is provided at the lower end of the locking sleeve (13) for abutting against the lower end of the sealing cavity (12); The fixing bracket (11) has a first internal thread (22) on its inner wall, the sealing chamber (12) has a first external thread (21) matching the first internal thread (22) on its outer wall, the fixing bracket (11) has a second external thread (23) on its outer wall, and the locking sleeve (13) has a second internal thread (24) matching the second external thread (23) on its inner wall. The sealing performance of the sealing element (5) is reduced, and the sealing element (5) can be compressed again to achieve sealing by rotating the sealing chamber (12).

2. The sealing device on the screw pump drive device that can be retrofitted on site according to claim 1, characterized in that: A filling block (18) is radially mounted on the upper end of the sealing cavity insertion channel (16), and the upper end of the filling block (18) and the upper end of the sealing cavity (12) respectively abut against the lower end of the sealing member (5); The sealing cavity insertion channel (16) is provided with a filling groove (17), and opposite side walls of the filling groove (17) are respectively fixedly connected with a clamping platform (19), and the opposite end surfaces of the two clamping platforms (19) are arranged to be gradually reduced from the outside to the center, and the opposite end surfaces of the filling block (18) are provided with a clamping groove (20) matching the clamping platform (19).

3. The sealing device on the field-refittable screw pump drive device according to claim 1, characterized in that: A retaining ring (10) is provided in the area of ​​the bearing box (1) above the sealing member (5), and the upper end of the sealing member (5) abuts against the lower end of the retaining ring (10).

4. The sealing device on the screw pump drive device that can be retrofitted on site according to claim 3 is characterized in that: The retaining ring (10) comprises two semicircular rings that are butt-jointed, wherein an insertion block (14) is fixedly connected to the butt-jointed end surface of one of the semicircular rings, and an insertion groove (15) is provided on the butt-jointed end surface of the other semicircular ring.

5. The sealing device on the field-retrofittable screw pump drive device according to claim 1, characterized in that: A plurality of threaded holes (30) are arranged on the outer wall of the locking sleeve (13), and bolts are connected to the inner threads of the threaded holes (30), with the ends of the bolts abutting against the sealing cavity (12).

6. The sealing device on the field-retrofittable screw pump drive device according to claim 1, characterized in that: A disc-shaped boss (26) is provided on the top of the fixing bracket (11), and a mounting hole (27) is provided on the disc-shaped boss (26) and is aligned with the threaded hole (9) of the bearing box. The screw (6) is inserted into the mounting hole (27), and the end of the screw (6) is threadedly connected to the threaded hole (9) of the bearing box.

7. The sealing device on the field-retrofittable screw pump drive device according to claim 1, characterized in that: The sealing member (5) comprises a polished rod sealing packing, and the sealing member (5) is provided with a scored opening along the axial direction.

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