A lubricating device for a power end of a plunger pump

Abstract

The present application belongs to the technical field of oil field development equipment, and particularly relates to a power end lubricating device of a plunger pump, aiming at solving the problem of poor splash lubrication effect of the plunger pump during low-speed operation. The present application comprises a gear pump installed on the plunger pump, and an oil inlet pipe and an oil outlet pipe connected between the gear pump and the plunger pump, wherein the oil inlet pipe and the oil outlet pipe are respectively communicated with the gear pump and the plunger pump; one end of the oil outlet pipe is connected with the oil outlet end of the gear pump, and the other end is connected with the upper side of the plunger pump body; one end of the oil inlet pipe is connected with the oil inlet end of the gear pump, and the other end is connected with the lower side of the plunger pump body; the gear pump pumps lubricating oil into the plunger pump through the oil outlet pipe to lubricate the crankshaft of the plunger pump, and the lubricating oil in the plunger pump is pumped out through the oil inlet pipe and injected into the gear pump, so as to realize the circulation of the lubricating oil. The present application solves the problem of high temperature of the pump and the damage of the parts caused by the high temperature of the power end due to insufficient lubrication during low-speed operation.

Description

Technical Field

[0001] This invention belongs to the technical field of oilfield development equipment, and specifically relates to a lubrication device for the power end of a plunger pump. Background Technology

[0002] High-pressure plunger pumps are the main equipment for high-pressure water injection in oilfields. The power end is a crucial component of the plunger pump, responsible for converting the rotational work of the motor into the reciprocating motion of the plunger via the crankshaft. This converts kinetic energy into potential energy, achieving pressurized injection, driving the formation reservoir, and increasing crude oil production. Currently, some oilfields, due to changes in injection requirements, are reducing the displacement of the plunger pump by lowering the motor frequency and thus the rotational speed. The current lubrication of the power end of the plunger pump relies on the high-speed rotation of the crankshaft to deliver lubricating oil to the parts requiring lubrication. This is currently a splash lubrication method. However, splash lubrication requires the crankshaft to have sufficient rotational speed (not less than 160 rpm) to throw the lubricating oil to the parts needing lubrication. In practice, due to adjustments in the injection volume, the pump speed is often reduced to below 160 rpm. The crankshaft speed is too slow to throw enough lubricating oil to the lubrication points, resulting in ineffective lubrication and cooling of the friction pairs. This leads to excessively high pump temperatures, causing high temperatures in the power end and damage to components.

[0003] In existing technology, such as the forced lubrication system for the power end of a pump body disclosed in CN205638905U, specifically, a first fixed disc is provided on the drive shaft of a gear oil pump. A wear-resistant sleeve is fitted on the drive shaft. A mounting groove adapted to the wear-resistant sleeve is provided at the end of the high-speed shaft facing the gear oil pump. The wear-resistant sleeve is embedded in the mounting groove. The first fixed disc and the wear-resistant sleeve are fixedly connected to the high-speed shaft by bolts and are coaxially arranged with the high-speed shaft. A second fixed disc is provided on the drive shaft. A rolling bearing is fitted on the high-speed shaft. The inner ring of the rolling bearing is fixedly connected to the high-speed shaft, and the outer ring of the rolling bearing is fixedly connected to the second fixed disc. The second fixed disc is coaxially arranged with the high-speed shaft. This structure requires heat treatment for installation, which is time-consuming and labor-intensive. Summary of the Invention

[0004] In order to solve the above-mentioned problems in the prior art, namely the problem of poor splash lubrication effect when the plunger pump is running at low speed, the present invention provides a lubrication device for the power end of the plunger pump.

[0005] This application discloses a lubrication device for the power end of a plunger pump, which adopts the following technical solution:

[0006] A lubrication device for the power end of a plunger pump includes a gear pump mounted on the plunger pump, and an oil inlet pipe and an oil outlet pipe connected between the gear pump and the plunger pump, the oil inlet pipe and the oil outlet pipe being respectively connected to the gear pump and the plunger pump.

[0007] One end of the oil outlet pipe is connected to the oil outlet of the gear pump, and the other end is connected to the upper side of the plunger pump body; one end of the oil inlet pipe is connected to the oil inlet of the gear pump, and the other end is connected to the lower side of the plunger pump body.

[0008] The gear pump pumps lubricating oil into the plunger pump through the oil outlet pipe to lubricate the crankshaft of the plunger pump, and then draws out the lubricating oil from the plunger pump through the oil inlet pipe and injects it into the gear pump to achieve the circulation of lubricating oil.

[0009] By adopting the above technical solution, the oil inlet pipe is connected to the lower side of the plunger pump, and the oil outlet pipe is connected to the oil filling hole on the top of the plunger pump leading to the crosshead slide. When the plunger pump is running, the crankshaft rotates, driving the coupling to rotate, which in turn drives the gears in the gear pump to rotate and mesh. As the gears rotate, the volume of the suction chamber gradually increases, forming a vacuum, thereby drawing in the lubricating oil from the plunger pump; while the volume of the discharge chamber gradually decreases, squeezing out and discharging the liquid, which then enters the oil filling hole of the crosshead slide through the oil outlet pipe. The lubricating oil can directly lubricate the crosshead, thereby lubricating the connecting rod and other friction pairs. Sufficient lubricating oil in the crosshead and connecting rod can adequately lubricate and reduce the temperature of the friction pairs, ensuring the normal operation of the power end.

[0010] Optionally, the crankshaft in the plunger pump is connected to the input shaft of the gear pump via a coupling.

[0011] Optionally, the piston pump has an intermediate rod installed at one end of its crankshaft, with one end of the intermediate rod inserted into the end of the crankshaft, and a coupling installed at the other end of the intermediate rod.

[0012] Optionally, the bearing cover is equipped with a mounting cover that covers the connection between the coupling and the intermediate rod, and the connection between the coupling and the input shaft of the gear pump; the mounting cover and the bearing cover are detachably connected.

[0013] Optionally, an asbestos gasket is installed between the mounting cover and the bearing cover.

[0014] By adopting the above technical solution, the sealing performance between the mounting cover and the bearing cover is improved.

[0015] Optionally, the mounting cover consists of an upper cover and a lower cover, which are fastened together, and both the upper and lower covers are detachably connected to the bearing cover.

[0016] By adopting the above technical solution, the installation of the cover is facilitated.

[0017] Optionally, two oil inlet pipes are provided, and the ends of the two oil outlet pipes connected to the plunger pump are arranged at intervals.

[0018] By adopting the above technical solution, the lubricating oil pumped into the plunger pump via the gear pump through the oil outlet pipe can provide a wider range of lubrication for the crankshaft in the plunger pump. The lubricating oil entering the plunger pump to lubricate the crankshaft flows into the oil inlet pipe under its own gravity, and then flows back to the gear pump through the oil inlet pipe, thereby realizing the circulation lubrication of the lubricating oil between the gear pump and the plunger pump, improving the lubrication effect.

[0019] Optionally, the positions where the inlet pipe and plunger pump are connected are aligned with the positions where the outlet pipe and plunger pump are connected.

[0020] By adopting the above technical solution, it is convenient for the lubricating oil after lubricating the crankshaft to flow into the oil inlet pipe.

[0021] Optionally, an installation filter is installed on the oil inlet pipe.

[0022] By adopting the above technical solution, the filter is used to filter particulate impurities in the lubricating oil, preventing particulate impurities from entering the friction pair of the gear pump and causing damage to the power end components.

[0023] The beneficial effects of the present invention are as follows: The plunger pump power end lubrication device of the present invention enables the crankshaft to drive the gear pump to deliver lubricating oil to the parts that need lubrication when the crankshaft is running at low speed through the crankshaft and coupling. This avoids the defect of insufficient lubrication due to splashing when the crankshaft is running at low speed, thereby solving the problem of excessive pump temperature and high temperature phenomenon at the power end caused by insufficient lubrication at low speed, which leads to damage to the parts. Attached Figure Description

[0024] Other features, objects, and advantages of this application will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0025] Figure 1 This is a schematic diagram of the lubrication device on the power end of the plunger pump in this embodiment;

[0026] Figure 2 This is a schematic diagram of the connection between the crankshaft and the gear pump in this embodiment;

[0027] Figure 3 This is a schematic diagram showing the connection between the mounting rod and the bearing cover in this embodiment.

[0028] Explanation of reference numerals in the attached drawings: 1. Piston pump; 2. Crankshaft; 3. Gear pump; 4. Oil inlet pipe; 5. Oil outlet pipe; 6. Intermediate rod; 7. Bearing cap; 8. Coupling; 9. Mounting cover; 91. Upper cover; 92. Lower cover; 10. Filter. Detailed Implementation

[0029] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention. Furthermore, it should be noted that, for ease of description, only the parts relevant to the invention are shown in the accompanying drawings.

[0030] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0031] This invention provides a lubrication device for the power end of a plunger pump, as described above. Figure 1 The lubrication device of the piston pump power end includes a gear pump 3 connected to the crankshaft 2 of the piston pump 1. An oil inlet pipe 4 and an oil outlet pipe 5 are connected between the gear pump 3 and the piston pump 1. The oil inlet pipe 4 and the oil outlet pipe 5 are respectively connected to the gear pump 3 and the piston pump 1. The gear pump 3 pumps lubricating oil into the piston pump 1 through the oil outlet pipe 5 for lubrication, and draws out the lubricating oil that has been lubricated in the piston pump 1 through the oil inlet pipe 4 and injects it into the gear pump 3 to realize the circulation of lubricating oil.

[0032] Reference Figure 2 , Figure 3 An intermediate rod 6 is installed at one end of the crankshaft 2 of the plunger pump 1. One end of the intermediate rod 6 is inserted into the end of the crankshaft 2, and the connection between the intermediate rod 6 and the end of the crankshaft 2 is located outside the bearing cover 7 of the plunger pump 1. A coupling 8 is installed at the other end of the intermediate rod 6, which connects the input shaft of the gear pump 3 to the intermediate rod 6. The coupling 8 is connected to the input shaft of the gear pump 3 by a key.

[0033] An installation cover 9 is installed on the bearing cover 7 to cover the connection between the coupling 8 and the intermediate rod 6, and the connection between the coupling 8 and the input shaft of the gear pump 3. The installation cover 9 and the bearing cover 7 are fixed together by bolts. An asbestos board gasket is installed between the installation cover 9 and the bearing cover 7 to increase the sealing of the connection.

[0034] The mounting cover 9 consists of an upper cover 91 and a lower cover 92. The upper cover 91 and the lower cover 92 are fastened together, and both the upper cover 91 and the lower cover 92 are fixed to the bearing cover 7 by bolts. During installation, the coupling 8 is installed first, followed by the lower cover 92. The upper cover 91 is not installed yet. When connecting the gear pump 3 and the coupling 8, the direction of the keyway needs to be observed and aligned before installation. The upper cover 91 can only be installed after the coupling 8 is fully aligned.

[0035] Reference Figure 1The oil inlet pipe 4 and oil outlet pipe 5 are connected to the gear pump 3 and the plunger pump 1, respectively. Two oil inlet pipes 4 are provided, with one end of each outlet pipe 5 connected to the oil outlet of the gear pump 3 and the other end connected to the upper part of the plunger pump 1. The ends of the two outlet pipes 5 connected to the plunger pump 1 are spaced apart, allowing the lubricating oil pumped into the plunger pump 1 by the gear pump 3 through the outlet pipes 5 to provide a wider range of lubrication for the crankshaft 2 in the plunger pump 1. Two oil inlet pipes 4 are also provided, with one end connected to the oil inlet of the gear pump 3 and the other end connected to the lower part of the plunger pump 1. The ends of the two inlet pipes 4 connected to the plunger pump 1 are spaced apart, allowing the lubricating oil entering the plunger pump 1 to lubricate the crankshaft 2 to flow into the oil inlet pipe 4 under its own gravity, and then return to the gear pump 3 via the oil inlet pipe 4. This achieves circulating lubrication between the gear pump 3 and the plunger pump 1, improving the lubrication effect. The connection points of the oil inlet pipe 4 and the plunger pump 1 can be aligned with those of the oil outlet pipe 5 and the plunger pump 1 to facilitate the flow of lubricating oil from the crankshaft 2 into the oil inlet pipe 4. Furthermore, a filter 10 is installed on the oil inlet pipe 4 to filter particulate impurities in the lubricating oil, preventing these impurities from entering the friction pair of the gear pump 3 and causing damage to the power-end components. It should be further noted that the filter 10 should be cleaned regularly to ensure its filtration effectiveness.

[0036] The method of using a plunger pump power end lubrication device disclosed in this application embodiment is as follows: A hole is drilled at the end of the crankshaft 2 of the plunger pump 1 to install an intermediate rod 6, then a coupling 8 is installed, followed by the installation of a bearing cover 7 and a lower cover 92. A gear pump 3 is connected to the coupling 8, and an upper cover 91 is installed. An oil inlet pipe 4 is connected to the lower side of the plunger pump 1. A filter 10 is installed on the oil inlet pipe 4 to prevent impurities from entering the gear pump 3. An oil outlet pipe 5 is connected to the oil injection hole on the plunger pump 1 leading to the crosshead slide. When the plunger pump 1 is running, the crankshaft 2 rotates, driving the coupling 8 to rotate, thereby driving the gears in the gear pump 3 to rotate and mesh. As the gears in the gear pump 3 rotate, the volume of the suction chamber gradually increases, forming a vacuum, thereby drawing in the lubricating oil from the plunger pump 1; while the volume of the discharge chamber gradually decreases, squeezing out and discharging the liquid, which enters the oil injection hole of the crosshead slide through the oil outlet pipe 5. Lubricating oil can directly lubricate the crosshead, thereby lubricating friction pairs such as the connecting rod. With sufficient lubricating oil, the crosshead and connecting rod can be adequately lubricated, reducing the temperature of the friction pairs and ensuring normal operation of the power end.

[0037] The plunger pump power end lubrication device of the present invention enables the crankshaft 2 to drive the gear pump 3 to deliver lubricating oil to the parts that need lubrication when the crankshaft 2 is running at low speed through the crankshaft 2 and coupling 8. This avoids the defect of insufficient lubrication due to splashing when the crankshaft 2 is running at low speed, thereby solving the problem of excessive pump temperature and high temperature phenomenon at the power end caused by insufficient lubrication at low speed, which leads to damage to parts.

[0038] The term "comprising" or any other similar term is intended to cover non-exclusive inclusion, such that a process, method, 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 in such process, method, article, or apparatus / device.

[0039] 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 these changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A lubrication device for the power end of a plunger pump, characterized in that: It includes a gear pump (3) installed on a plunger pump (1), and an oil inlet pipe (4) and an oil outlet pipe (5) are connected between the gear pump (3) and the plunger pump (1). The oil inlet pipe (4) and the oil outlet pipe (5) are respectively connected to the gear pump (3) and the plunger pump (1). One end of the oil outlet pipe (5) is connected to the oil outlet end of the gear pump (3), and the other end is connected to the upper side of the pump body of the plunger pump (1); one end of the oil inlet pipe (4) is connected to the oil inlet end of the gear pump (3), and the other end is connected to the lower side of the pump body of the plunger pump (1). The gear pump (3) pumps lubricating oil into the plunger pump (1) through the oil outlet pipe (5) to lubricate the crankshaft (2) of the plunger pump (1), and draws out the lubricating oil that has been lubricated in the plunger pump (1) through the oil inlet pipe (4) and injects it into the gear pump (3) to realize the circulation of lubricating oil.

2. The lubrication device for the power end of the plunger pump according to claim 1, characterized in that: The crankshaft (2) of the plunger pump (1) is connected to the input shaft of the gear pump (3) via a coupling (8).

3. The lubrication device for the power end of the plunger pump according to claim 2, characterized in that: The piston pump (1) has an intermediate rod (6) installed at one end of the crankshaft (2), with one end of the intermediate rod (6) inserted into the end of the crankshaft (2), and a coupling (8) installed at the other end of the intermediate rod (6).

4. The lubrication device for the power end of the plunger pump according to claim 1, characterized in that: The bearing cover (7) is equipped with a mounting cover (9) that covers the connection between the coupling (8) and the intermediate rod (6) and the connection between the coupling (8) and the input shaft of the gear pump (3); the mounting cover (9) and the bearing cover (7) are detachably connected.

5. The lubrication device for the power end of the plunger pump according to claim 4, characterized in that: An asbestos gasket is installed between the mounting cover (9) and the bearing cover (7).

6. The lubrication device for the power end of the plunger pump according to claim 4, characterized in that: The mounting cover (9) is divided into an upper cover (91) and a lower cover (92). The upper cover (91) and the lower cover (92) are fastened together, and both the upper cover (91) and the lower cover (92) are detachably connected to the bearing cover (7).

7. The lubrication device for the power end of the plunger pump according to claim 1, characterized in that: There are two oil inlet pipes (4), and the two oil outlet pipes (5) are arranged at intervals at one end connected to the plunger pump (1).

8. The lubrication device for the power end of the plunger pump according to claim 7, characterized in that: The position where the oil inlet pipe (4) and the plunger pump (1) are connected is aligned with the position where the oil outlet pipe (5) and the plunger pump (1) are connected.

9. The lubrication device for the power end of the plunger pump according to claim 7, characterized in that: An installation filter (10) is installed on the oil inlet pipe (4).

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