A differential pressure fracturing pump plunger seal

Abstract

The application discloses a differential pressure fracturing pump plunger sealing device and relates to the technical field of fracturing pump plunger sealing. The application aims to solve the problem that the sealing mode of reducing the pressure difference by using the size end area ratio of the differential pressure plunger is limited in use range and is difficult to meet the adaptation to different pressure injection conditions. The application comprises a pump head, a plunger, a primary sealing assembly, a secondary sealing assembly, a primary pressure cap and a secondary pressure cap. An annular space is formed between the primary pressure cap and the pump head. A differential pressure hole is further formed in the pump head and is communicated with a plunger cavity in the pump head. A differential pressure assembly is arranged in the differential pressure hole. The differential pressure hole is communicated with the annular space. A differential pressure sleeve of the differential pressure assembly is provided with a differential pressure column. A counter hole is formed in the top end of the differential pressure column. A threaded hole is formed in a gland corresponding to the counter hole. A counter column is threadedly connected in the threaded hole. The bottom end of the counter column is inserted into the corresponding counter hole.

Description

Technical Field

[0001] This invention relates to the technical field of plunger sealing for fracturing pumps, and specifically to a differential pressure fracturing pump plunger sealing device. Background Technology

[0002] Fracturing is a key method in oil and gas extraction to "bring out stagnant oil and gas," especially for "sharpening stone" level reservoirs such as low-permeability shale and tight oil, where economic extraction is basically impossible without fracturing.

[0003] The fracturing pump is a key core piece of equipment, and the reciprocating plungers in the fracturing pump employ plunger sealing devices with multiple V-rings connected in series. However, existing measures to extend the service life of plunger seals mainly involve improving the structure and materials of the sealing rings in the pressure pump sealing device, as well as modifying the structural shape of the pressure bearing ring. But these methods are not very effective in improving the service life of the pump plunger seals, and the pressure difference during plunger seal operation is a key factor affecting its service life.

[0004] Regarding the above issues, the Chinese patent titled "A Differential Pressure Fracturing Pump Plunger Sealing Device" (publication number CN114576158B) makes a core contribution by using the differential pressure plunger area difference plus the back pressure of the drainage to reduce the differential pressure between the primary and secondary seals, thereby improving the lifespan of the seals.

[0005] However, although the aforementioned patents can improve the lifespan of seals, their products still have many drawbacks during use. For example, the large / small end face area ratio of the differential pressure plunger is machined to a fixed value, while the actual operating conditions of the pressure pump range from 70 to 140 MPa. A fixed area ratio means that when deviating from the design point, a certain stage will still be unbalanced, resulting in excessive pressure differential on the seal. Therefore, the products in the aforementioned patents are quite limited in actual use and cannot meet high adaptability requirements. Summary of the Invention

[0006] To address the aforementioned problem—namely, the limited applicability of sealing methods that utilize the differential pressure plunger's large-to-small end area ratio to reduce differential pressure and adapt to different injection pressure conditions—this invention proposes a differential pressure fracturing pump plunger sealing device. This device includes a pump head, within which a plunger is housed. A primary sealing assembly is fitted onto the plunger and secured by a primary pressure cap, forming an annular space between the primary pressure cap and the pump head. A secondary sealing assembly is also fitted onto the plunger and secured by a secondary pressure cap, located inside the primary pressure cap. A differential pressure orifice perpendicular to the plunger is also provided within the pump head. The differential pressure assembly is configured to communicate with the plunger cavity inside the pump head and is provided in the differential pressure orifice. The differential pressure orifice is connected to the annular space. The differential pressure assembly includes a differential pressure sleeve fitted inside the differential pressure orifice. The differential pressure sleeve has a radial hole for communicating with the annular space. A pressure cap is threaded to the top of the differential pressure sleeve. A differential pressure column is provided inside the differential pressure sleeve. The projected area of ​​the top of the differential pressure column is larger than the projected area of ​​the bottom of the differential pressure column. At least one offset hole is provided at the top of the differential pressure column. A threaded hole is provided on the pressure cap corresponding to the offset hole. An offset column is threaded to the threaded hole. The bottom end of the offset column is inserted into the corresponding offset hole.

[0007] A further provision of the present invention is that three offset holes are provided.

[0008] This invention also proposes a differential pressure fracturing pump plunger sealing device, comprising a pump head, a plunger disposed within the pump head, a primary sealing assembly fitted onto the plunger, the primary sealing assembly being tightened by a primary pressure cap, the primary pressure cap forming an annular space with the pump head; a secondary sealing assembly further fitted onto the plunger, the secondary sealing assembly being tightened by a secondary pressure cap, and the secondary sealing assembly being disposed inside the primary pressure cap; a differential pressure orifice perpendicular to the plunger is also provided within the pump head, the differential pressure orifice communicating with the plunger cavity within the pump head, a differential pressure assembly disposed within the differential pressure orifice; the differential pressure orifice communicating with the annular space; the differential pressure assembly including a differential pressure force fitted within the differential pressure orifice. The differential pressure sleeve has a radial hole for connecting the annular space. A pressure cap is threaded to the top of the differential pressure sleeve. A differential pressure column is provided inside the differential pressure sleeve. The projected area of ​​the top of the differential pressure column is larger than the projected area of ​​the bottom of the differential pressure column. A coaxially arranged offsetting hole is provided at the top of the differential pressure column. At least one offsetting ring hole is also coaxially provided at the top of the differential pressure column. The diameter of the offsetting ring is larger than the diameter of the offsetting hole. An offsetting column is detachably connected to the pressure cap corresponding to the offsetting column. An offsetting sleeve is detachably connected to the pressure cap corresponding to the offsetting ring hole. The bottom end of the offsetting column is inserted into the offsetting hole, and the bottom end of the offsetting sleeve is inserted into the offsetting ring hole.

[0009] A further provision of the present invention is that: two offset ring holes are provided, and the diameters of the two offset ring holes are different.

[0010] A further feature of the present invention is that the pump head has a transverse hole and a longitudinal hole that are interconnected. One end of the transverse hole is connected to the differential pressure hole, and one end of the longitudinal hole is connected to the annular space. A one-way valve is installed at the end of the transverse hole away from the differential pressure hole, and the other end of the one-way valve is used to connect to the return oil device.

[0011] A further feature of the present invention is that a third-stage sealing assembly is provided inside the second-stage pressure cap, and the third-stage sealing assembly is also sleeved on the plunger.

[0012] A further feature of the present invention is that an annular pressure relief chamber is provided inside the secondary pressure cap, the pressure relief chamber is located between the secondary sealing assembly and the tertiary sealing assembly, the pressure relief chamber is connected to the plunger chamber, and the pressure relief chamber is also connected to a pressure relief valve, which is located outside the secondary pressure cap.

[0013] The beneficial effects of this invention are as follows:

[0014] 1. By setting offset holes and offset columns, the positive projection area of ​​the top of the differential pressure column in contact with the lubricating oil can be adjusted. Then, by inserting the offset column, the area ratio of the pressure-bearing surfaces at both ends of the differential pressure column can be adjusted. Furthermore, the differential pressure can be adjusted by adjusting the area ratio, so that it can adapt to different pressure conditions.

[0015] 2. By cooperating with the offset column and the offset hole, and cooperating with the offset sleeve and the offset ring hole, the positive projection area of ​​the top of the differential pressure column in contact with the lubricating oil can be adjusted. Then, by inserting the offset column or the offset sleeve, the area ratio of the pressure-bearing surfaces at both ends of the differential pressure column can be adjusted. Furthermore, the differential pressure can be adjusted by adjusting the area ratio, so that it can be adapted to different pressure conditions.

[0016] 3. By connecting the transverse hole to the oil return device, the lubricating oil can achieve semi-forced circulation in the differential pressure sleeve, radial hole, transverse hole, longitudinal hole, and annular space, thereby removing the frictional heat generated during the high-speed reciprocating motion of the plunger and removing wear debris, thus improving the overall life of the sealing device.

[0017] 4. Through the cooperation of the pressure relief chamber and the tertiary sealing assembly, the leakage can be relieved in time when the secondary sealing assembly fails, preventing fracturing fluid from spraying out or entering the oil tank and causing emulsification. At the same time, since the tertiary sealing assembly does not participate in the sealing work under normal circumstances, it only participates in preventing external spraying and assisting in the pressure relief work when the secondary sealing assembly fails or there is a leak. Therefore, the service life of the tertiary sealing assembly is longer, and the pressure difference experienced by the tertiary sealing assembly is only a small part of the pressure relief of the secondary sealing assembly, so its wear is extremely slow, providing a final safety guarantee for the equipment. Attached Figure Description

[0018] Figure 1 A schematic diagram of the structure of Embodiment 1 is shown.

[0019] Figure 2 A schematic diagram of the differential pressure column in Example 1 is shown.

[0020] Figure 3 A schematic diagram of the structure of Embodiment 2 is shown. Figure 1 .

[0021] Figure 4 A schematic diagram of the structure of Embodiment 2 is shown. Figure 2 .

[0022] Figure 5 A schematic diagram of the structure of Embodiment 2 is shown. Figure 3 .

[0023] Figure 6 A schematic diagram of the differential pressure column in Example 2 is shown.

[0024] Figure 7 It shows Figure 3 Schematic diagram of the structure of a medium pressure differential column.

[0025] Figure 8 It shows Figure 4 Schematic diagram of the structure of a medium pressure differential column.

[0026] Figure 9 It shows Figure 5 Schematic diagram of the structure of a medium pressure differential column.

[0027] Reference numerals: 1. Pump head; 11. Differential pressure orifice; 12. Annular space; 13. Transverse orifice; 131. Check valve; 14. Longitudinal orifice; 2. Piston; 3. Primary sealing assembly; 4. Primary pressure cap; 5. Differential pressure assembly; 51. Differential pressure sleeve; 511. Radial orifice; 52. Pressure gland; 53. Differential pressure column; 531. Counteracting orifice; 532. Counteracting ring orifice; 54. Counteracting column; 55. Counteracting sleeve; 6. Secondary pressure cap; 61. Pressure relief chamber; 7. Tertiary sealing assembly; 8. Pressure relief valve; 9. Secondary sealing assembly. Detailed Implementation

[0028] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0029] Example 1.

[0030] refer to Figure 1-2 The present invention proposes a sealing device for a differential pressure fracturing pump plunger 2, including a pump head 1, a plunger 2 installed inside the pump head 1, a primary sealing component 3 sleeved on the plunger 2, and the primary sealing component 3 being tightened by a primary pressure cap 4, that is, the small diameter end of the primary pressure cap 4 is sleeved on the plunger 2 and extends into the pump head 1 to tighten the primary sealing component 3.

[0031] An annular space 12 is formed between the primary pressure cap 4 and the pump head 1. Several radial grooves are also provided at the end of the primary pressure cap 4 that is pressed against the primary sealing assembly 3. These radial grooves are arranged at equal angles along their circumference and communicate with the annular space 12. A secondary sealing assembly 9 is also fitted onto the plunger 2. The secondary sealing assembly 9 is pressed against the primary pressure cap 6 and is located inside the primary pressure cap 4. The annular space 12 is located between the primary sealing assembly 3 and the secondary sealing assembly 9.

[0032] A differential pressure orifice 11 is also provided inside the pump head 1. The differential pressure orifice 11 is set perpendicular to the plunger 2. A differential pressure assembly 5 is installed inside the differential pressure orifice 11, and the differential pressure orifice 11 communicates with the annular space 12. The differential pressure assembly 5 includes a differential pressure sleeve 51 fitted inside the differential pressure orifice 11. A radial hole 511 for communicating with the annular space 12 is provided on the differential pressure sleeve 51. A pressure cap 52 is threaded to the top end of the differential pressure sleeve 51. A differential pressure column 53 is coaxially installed inside the differential pressure sleeve 51. The differential pressure column 53 is a stepped column, wherein the diameter of the bottom end of the differential pressure column 53 is smaller than the diameter of its top end, so that the projected area of ​​the top end of the differential pressure column 53 is larger than the projected area of ​​the bottom end of the differential pressure column 53.

[0033] The top of the differential pressure column 53 has three offset holes 531. The pressure cap 52 has threaded holes corresponding to the offset holes 531, with offset columns 54 threaded into the threaded holes. The bottom end of the offset column 54 is inserted into the corresponding offset hole 531, so that the offset column 54 can cover the projected area of ​​the offset hole 531. Therefore, when the differential pressure column 53 is under pressure, the torque transmission area ratio of the differential pressure column 53 is denoted as: bottom area : top projected area - projected area of ​​offset hole 531. Since there are three offset holes 531, the area ratio can be adjusted to four levels: no offset column 54, with... The application considers the installation of one, two, and three counteracting columns. The ratio of the top projected area of ​​the differential pressure column 53 to the bottom projected area of ​​the differential pressure column 53 is denoted as n:1. This application uses the actual operating conditions of a fracturing pump (70-140 MPa) as an example. When no counteracting column 54 is installed, n is denoted as 3, resulting in an area ratio of 3:1, suitable for a 140 MPa operating condition. When one counteracting column 54 is installed, the area ratio is 2.5:1, suitable for a 120 MPa operating condition. When two counteracting columns 54 are installed, the area ratio is 2:1, suitable for a 100 MPa operating condition. When three counteracting columns 54 are installed, the area ratio is 1.5:1, suitable for a 70 MPa operating condition.

[0034] It should be noted that when the offsetting column 54 is not inserted into the threaded hole, a plug needs to be threaded onto it. The diameter of the offsetting column 54 hole can be set according to the usage requirements, and the diameter of each offsetting hole 531 can also be set differently, which can be designed according to the usage requirements. That is, the purpose of adjusting the area ratio is achieved by subtracting the area of ​​the offsetting hole 531 offset by the offsetting column 54 from the positive projection area of ​​the top of the differential pressure column 53.

[0035] The pump head 1 has a transverse hole 13 and a longitudinal hole 14 that are interconnected. One end of the transverse hole 13 is connected to the differential pressure hole 11, and then connected to the radial hole 511 of the differential pressure sleeve 51 through the differential pressure hole 11. One end of the longitudinal hole 14 is connected to the annular space 12. The lubricating oil in the differential pressure sleeve 51 can flow into the longitudinal hole 14 through the transverse hole 13, and then into the annular space 12 through the longitudinal hole 14. It then enters the radial groove through the annular space 12 to achieve the lubrication of the plunger 2 and provide back pressure for the first-stage sealing assembly 3.

[0036] A one-way valve 131 is also installed at the other end of the transverse hole 13. The one-way valve 131 is installed on the outer surface of the pump head 1, with its opening facing outwards. The other end of the one-way valve 131 is connected to the oil return device, thereby enabling the lubricating oil in the pump head 1 to achieve semi-forced circulation, so as to remove internal heat and wear debris. At the same time, the one-way valve 131 can also prevent the lubricating oil from flowing back.

[0037] The secondary pressure cap 6 also houses a tertiary sealing assembly 7, which is also fitted onto the plunger 2. The secondary pressure cap 6 also has an annular pressure relief chamber 61 located between the secondary sealing assembly 9 and the tertiary sealing assembly 7. The pressure relief chamber 61 is connected to the plunger 2 cavity via a channel and is also connected to a pressure relief valve 8, which is installed on the outer surface of the secondary pressure cap 6. When the secondary sealing assembly 9 fails or leaks, the pressure relief valve 8 can promptly relieve the pressure of the fracturing fluid leaking from the secondary sealing assembly 9, while the tertiary sealing assembly 7 serves as a final sealing guarantee to prevent fracturing fluid from spraying out.

[0038] It should also be noted that the primary sealing assembly 3, the secondary sealing assembly 9, and the tertiary sealing assembly 7 have the same composition, all including front and rear support rings, with a sealing ring and a pressure ring provided between the two support rings. This structure is existing technology, so it will not be described in detail here.

[0039] Example 2

[0040] refer to Figure 3-9 This invention proposes a differential pressure fracturing pump plunger 2 sealing device, including a pump head 1, a plunger 2 installed inside the pump head 1, a primary sealing component 3 sleeved on the plunger 2, and the primary sealing component 3 is tightened by a primary pressure cap 4, that is, the small diameter end of the primary pressure cap 4 is sleeved on the plunger 2 and extends into the pump head 1 to tighten the primary sealing component 3.

[0041] An annular space 12 is formed between the primary pressure cap 4 and the pump head 1. Several radial grooves are also provided at the end of the primary pressure cap 4 that is pressed against the primary sealing assembly 3. These radial grooves are arranged at equal angles along their circumference and communicate with the annular space 12. A secondary sealing assembly 9 is also fitted onto the plunger 2. The secondary sealing assembly 9 is pressed against the primary pressure cap 6 and is located inside the primary pressure cap 4. The annular space 12 is located between the primary sealing assembly 3 and the secondary sealing assembly 9.

[0042] A differential pressure orifice 11 is also provided inside the pump head 1. The differential pressure orifice 11 is set perpendicular to the plunger 2. A differential pressure assembly 5 is installed inside the differential pressure orifice 11, and the differential pressure orifice 11 communicates with the annular space 12. The differential pressure assembly 5 includes a differential pressure sleeve 51 fitted inside the differential pressure orifice 11. A radial hole 511 for communicating with the annular space 12 is provided on the differential pressure sleeve 51. A pressure cap 52 is threaded to the top end of the differential pressure sleeve 51. A differential pressure column 53 is coaxially installed inside the differential pressure sleeve 51. The differential pressure column 53 is a stepped column, wherein the diameter of the bottom end of the differential pressure column 53 is smaller than the diameter of its top end, so that the projected area of ​​the top end of the differential pressure column 53 is larger than the projected area of ​​the bottom end of the differential pressure column 53.

[0043] A counteracting hole 531 is provided at the top of the differential pressure column 53. The counteracting hole 531 is coaxially arranged with the differential pressure column 53. A threaded hole is provided on the pressure cap 52 corresponding to the counteracting hole 531. A counteracting column 54 is threadedly connected to the threaded hole. The bottom end of the counteracting column 54 is inserted into the corresponding counteracting hole 531. In this way, the counteracting column 54 can cover the projected area of ​​the counteracting hole 531. Therefore, when the differential pressure column 53 is under pressure, when it transmits torque upward, the torque transmission area ratio of the differential pressure column 53 is recorded as: bottom end area: top projected positive area - counteracting hole 531 positive projected area.

[0044] Two offset ring holes 532 are also provided at the top of the differential pressure column 53. The diameter of the offset ring hole 532 is larger than that of the offset hole 531. The diameters of the two offset ring holes 532 are different. Both offset ring holes 532 are coaxial with the offset hole 531. Two offset sleeves 55 can also be detachably connected to the lower surface of the pressure cover 52. The two offset sleeves 55 are respectively set corresponding to the two offset ring holes 532, and the bottom end of the offset sleeve 55 is inserted into the offset ring hole 532 to offset the area of ​​the differential pressure column 53 covered by the offset sleeve 55.

[0045] It should be noted that, during use, one of the two offset sleeves 55 and one offset column 54 can be used. That is, since the diameters of the two offset sleeves 55 are different, and the diameters of the offset sleeves 55 and the offset column 54 are also different, the areas they can cover are also different, and the area ratios that can be adjusted are 3:1, 2.5:1, 2:1, and 1.5:1, respectively, thus meeting the working conditions of fracturing pumps of 140MPa, 120MPa, 100MPa, and 70MPa.

[0046] The pump head 1 has a transverse hole 13 and a longitudinal hole 14 that are interconnected. One end of the transverse hole 13 is connected to the differential pressure hole 11, and then connected to the radial hole 511 of the differential pressure sleeve 51 through the differential pressure hole 11. One end of the longitudinal hole 14 is connected to the annular space 12. The lubricating oil in the differential pressure sleeve 51 can flow into the longitudinal hole 14 through the transverse hole 13, and then into the annular space 12 through the longitudinal hole 14. It then enters the radial groove through the annular space 12 to achieve the lubrication of the plunger 2 and provide back pressure for the first-stage sealing assembly 3.

[0047] A one-way valve 131 is also installed at the other end of the transverse hole 13. The one-way valve 131 is installed on the outer surface of the pump head 1, with its opening facing outwards. The other end of the one-way valve 131 is connected to the oil return device, thereby enabling the lubricating oil in the pump head 1 to achieve semi-forced circulation, so as to remove internal heat and wear debris. At the same time, the one-way valve 131 can also prevent the lubricating oil from flowing back.

[0048] The secondary pressure cap 6 also houses a tertiary sealing assembly 7, which is also fitted onto the plunger 2. The secondary pressure cap 6 also has an annular pressure relief chamber 61 located between the secondary sealing assembly 9 and the tertiary sealing assembly 7. The pressure relief chamber 61 is connected to the plunger 2 cavity via a channel and is also connected to a pressure relief valve 8, which is installed on the outer surface of the secondary pressure cap 6. When the secondary sealing assembly 9 fails or leaks, the pressure relief valve 8 can promptly relieve the pressure of the fracturing fluid leaking from the secondary sealing assembly 9, while the tertiary sealing assembly 7 serves as a final sealing guarantee to prevent fracturing fluid from spraying out.

[0049] It should also be noted that the primary sealing assembly 3, the secondary sealing assembly 9, and the tertiary sealing assembly 7 have the same composition, all including front and rear support rings, with a sealing ring and a pressure ring provided between the two support rings. This structure is existing technology, so it will not be described in detail here.

[0050] In summary, by setting the offset hole 531 and the offset column 54, the present invention can adjust the positive projection area of ​​the top of the pressure differential column 53 in contact with the lubricating oil, and further adjust the area ratio of the pressure-bearing surfaces at both ends of the pressure differential column 53 by inserting the offset column 54. Furthermore, the pressure differential can be adjusted by adjusting the area ratio, thereby enabling it to adapt to different pressure conditions.

[0051] By cooperating with the offset column 54 and the offset hole 531, and with the offset sleeve 55 and the offset ring hole 532, the positive projection area of ​​the top of the differential pressure column 53 in contact with the lubricating oil can be adjusted. Furthermore, by inserting the offset column 54 or the offset sleeve 55, the area ratio of the pressure-bearing surfaces at both ends of the differential pressure column 53 can be adjusted. In addition, the differential pressure can be adjusted by adjusting the area ratio, so that it can be adapted to different pressure conditions.

[0052] By connecting the transverse hole 13 to the oil return device, the lubricating oil can achieve semi-forced circulation in the differential pressure sleeve 51, radial hole 511, transverse hole 13, longitudinal hole 14, and annular space 12, thereby removing the frictional heat generated by the high-speed reciprocating motion of the plunger 2 and removing wear debris, so as to improve the overall service life of the sealing device.

[0053] By cooperating with the pressure relief chamber 61 and the tertiary sealing assembly 7, the leakage can be relieved immediately through the pressure relief chamber 61 when the secondary sealing assembly 9 fails, preventing fracturing fluid from spraying out or entering the oil tank and causing emulsification. At the same time, since the tertiary sealing assembly 7 does not participate in the sealing work under normal circumstances, it only participates in preventing external spraying and cooperating with the pressure relief work when the secondary sealing assembly 9 fails or there is a leak. Therefore, the service life of the tertiary sealing assembly 7 is longer, and the pressure difference experienced by the tertiary sealing assembly 7 is only a small part of the pressure relief of the secondary sealing assembly 9, so its wear is extremely slow, which can provide a final safety guarantee for the equipment.

[0054] Although the invention has been described with reference to preferred embodiments, various modifications can be made thereto and components can be replaced with equivalents without departing from the scope of the invention. In particular, the technical features mentioned in the various embodiments can be combined in any manner, provided there is no structural conflict. The invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

[0055] In the description of this invention, terms such as "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," which indicate direction or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. These are used merely for ease of description and do not indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation; therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0056] Furthermore, it should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0057] The term "comprising" or any other similar term is intended to cover non-exclusive inclusion, such that a process, article, or apparatus / device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to those processes, articles, or apparatus / devices.

[0058] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after such changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A differential pressure fracturing pump plunger sealing device, comprising a pump head (1), wherein a plunger (2) is disposed inside the pump head (1), a primary sealing assembly (3) is fitted on the plunger (2), the primary sealing assembly (3) is tightened by a primary pressure cap (4), and an annular space (12) is formed between the primary pressure cap (4) and the pump head (1); a secondary sealing assembly (9) is also fitted on the plunger (2), the secondary sealing assembly (9) is tightened by a secondary pressure cap (6), and the secondary sealing assembly (9) is disposed inside the primary pressure cap (4); a differential pressure hole (11) perpendicular to the plunger (2) is also opened inside the pump head (1), the differential pressure hole (11) 11) The differential pressure assembly (5) is configured to communicate with the plunger (2) cavity in the pump head (1), and the differential pressure orifice (11) is provided with a differential pressure component (5); the differential pressure orifice (11) is connected to the annular space (12); the differential pressure component (5) includes a differential pressure sleeve (51) sleeved in the differential pressure orifice (11), the differential pressure sleeve (51) is provided with a radial hole (511) for communicating with the annular space (12), the top end of the differential pressure sleeve (51) is threaded with a pressure cap (52), and a differential pressure column (53) is provided in the differential pressure sleeve (51), the top projection area of ​​the differential pressure column (53) is larger than the bottom projection area of ​​the differential pressure column (53), characterized in that: The top of the differential pressure column (53) has at least one offset hole (531), and the pressure cap (52) has a threaded hole corresponding to the offset hole (531). The offset column (54) is threadedly connected to the threaded hole, and the bottom end of the offset column (54) is inserted into the corresponding offset hole (531).

2. The differential pressure fracturing pump plunger sealing device according to claim 1, characterized in that: The offset hole (531) is provided in three parts.

3. A differential pressure fracturing pump plunger sealing device, comprising a pump head (1), wherein a plunger (2) is disposed inside the pump head (1), a primary sealing assembly (3) is fitted on the plunger (2), the primary sealing assembly (3) is tightened by a primary pressure cap (4), and an annular space (12) is formed between the primary pressure cap (4) and the pump head (1); a secondary sealing assembly (9) is also fitted on the plunger (2), the secondary sealing assembly (9) is tightened by a secondary pressure cap (6), and the secondary sealing assembly (9) is disposed inside the primary pressure cap (4); a differential pressure hole (11) perpendicular to the plunger (2) is also opened inside the pump head (1), the differential pressure hole (11) 11) The differential pressure assembly (5) is configured to communicate with the plunger (2) cavity in the pump head (1), and the differential pressure orifice (11) is provided with a differential pressure component (5); the differential pressure orifice (11) is connected to the annular space (12); the differential pressure component (5) includes a differential pressure sleeve (51) sleeved in the differential pressure orifice (11), the differential pressure sleeve (51) is provided with a radial hole (511) for communicating with the annular space (12), the top end of the differential pressure sleeve (51) is threaded with a pressure cap (52), and a differential pressure column (53) is provided in the differential pressure sleeve (51), the top projection area of ​​the differential pressure column (53) is larger than the bottom projection area of ​​the differential pressure column (53), characterized in that: The top end of the differential pressure column (53) is provided with a coaxially arranged offset hole (531). The top end of the differential pressure column (53) is also coaxially provided with at least one offset ring hole (532). The diameter of the offset ring hole (532) is larger than the diameter of the offset hole (531). The pressure cap (52) is detachably connected to the offset column (54) corresponding to the offset column (54). The pressure cap (52) is detachably connected to the offset ring hole (532). The bottom end of the offset column (54) is inserted into the offset hole (531). The bottom end of the offset sleeve (55) is inserted into the offset ring hole (532).

4. The differential pressure fracturing pump plunger sealing device according to claim 3, characterized in that: Two offset ring holes (532) are provided, and the diameters of the two offset ring holes (532) are different.

5. The differential pressure fracturing pump plunger sealing device according to claim 1 or 3, characterized in that: The pump head (1) has a transverse hole (13) and a longitudinal hole (14) that are interconnected. One end of the transverse hole (13) is connected to the differential pressure hole (11), and one end of the longitudinal hole (14) is connected to the annular space (12). A one-way valve (131) is installed on the end of the transverse hole (13) away from the differential pressure hole (11), and the other end of the one-way valve (131) is used to connect to the return oil equipment.

6. The differential pressure fracturing pump plunger sealing device according to claim 1 or 3, characterized in that: The secondary pressure cap (6) is also provided with a tertiary sealing assembly (7), which is also fitted onto the plunger (2).

7. The differential pressure fracturing pump plunger sealing device according to claim 6, characterized in that: The secondary pressure cap (6) also has an annular pressure relief chamber (61) inside. The pressure relief chamber (61) is located between the secondary sealing assembly (9) and the tertiary sealing assembly (7). The pressure relief chamber (61) is connected to the plunger (2) chamber. The pressure relief chamber (61) is also connected to a pressure relief valve (8). The pressure relief valve (8) is located outside the secondary pressure cap (6).

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