Liquid pumping and bin sweeping integrated operation method of submersible pump

Abstract

The application discloses a kind of liquid pumping, scanning warehouse integrated operation method of submerged pump, it is in the inside of submerged pump again setting a with internal oil suction pipe inner pump formation pump-in-pump structure, utilize the submerged pump and the external liquid pumping passage A formed with its communication snorkel, utilize the inner pump and the internal liquid pumping passage B formed with its communication internal oil suction pipe, the internal liquid pumping passage B is located in the inside of external liquid pumping passage A;When pumping, utilize external liquid pumping passage A and internal liquid pumping passage B simultaneously pump out the oil liquid in oil tank, complete pumping work;When the oil liquid in oil tank is all pumped out, utilize internal liquid pumping passage B and pump out the oil liquid remaining in submerged pump and the part of snorkel communicated therewith, complete scanning warehouse work.The application can realize pumping and scanning warehouse function once, both reduce the residual oil liquid inventory in oil tank, thereby reduce the waste of resources can reduce the labor intensity of operator, improve the work efficiency of unloading.

Description

Technical Field

[0001] This invention relates to a method for operating a submersible pump, and more particularly to an integrated method for pumping and sweeping a submersible pump, belonging to the field of liquid pump technology. Background Technology

[0002] Railway tank cars are railway vehicles used to transport petrochemical products. In recent years, with the rapid growth in demand for petrochemical products, more and more oil depots have chosen to use railway tank cars for oil transportation. Compared with other modes of transportation, railway tank cars have advantages such as large carrying capacity, high transportation speed, and low cost.

[0003] Railway trestle bridges connect trains and oil depots, facilitating the entry and exit of oil tankers and improving loading and unloading efficiency. The assembly and unloading arms installed on the trestle bridge play a crucial role. For example... Figure 1 As shown, the loading arm 1 is typically positioned in an inverted V-shape above the oil tank 2. A submersible pump 3 is connected to one end of the loading arm 1 and is in communication with it. When unloading oil from the oil tanker on the railway tank car, one end of the loading arm 1 is inserted into the tank 2, so that the submersible pump 3 at one end of the loading arm 1 is located in the oil collection pit 211 at the bottom of the tank 2. The other end of the loading arm 1 is connected to the tank area's oil pipeline. After unloading begins, the submersible pump 3 is activated to extract oil 4 from the tank 2. The oil 4 passes through the submersible pump 3 and the loading arm 1 sequentially and is then transported to the oil depot for storage via the tank area's oil pipeline.

[0004] The problem with the existing technology is: Figure 2 As shown, after the oil 4 in tank 2 is completely sucked out, although the submersible pump 3 is still working, there is no oil left to pump from tank 2, and it is full of air. Therefore, this will cause air to accumulate inside the submersible pump 3 and in the connected arm 1 (i.e., Figure 2A significant amount of oil 4 remains inside the vertical section of the loading arm (arm loader), which cannot be transported out. When unloading oil from one tanker to the next on a railway oil tanker, according to operating procedures, to ensure safety, the submersible pump 3 must be shut down first before inserting the loading arm with the submersible pump 3 into the next tanker for unloading. However, after shutting down the submersible pump 3, the oil 5 remaining inside the pump 3 and the suction pipe 1 of the loading arm will flow back into the tanker 2, leaving a large amount of oil in the tanker 2. Since each railway oil tanker has multiple tankers, if each tank has a large amount of oil remaining, it will result in a significant waste of resources. Therefore, in the existing technology, after shutting down the submersible pump 3, another self-priming pump device is needed to extract the large amount of oil remaining in the tanker 2 for cleaning. However, this operation requires pumping and cleaning of each oil tank, which greatly reduces work efficiency and increases the workload of operators.

[0005] Chinese invention patent application CN101191493A, published on June 4, 2008, discloses a submersible pump with side-suction, no backflow, and sweeping function. An annular cover is provided on the outside of the suction port of a centrifugal pump. The lower end of the cover is connected to a self-priming pump through a support column. The impeller of the self-priming pump and the impeller of the centrifugal pump share a hydraulic motor shaft. The side of the self-priming pump is provided with a suction port, and a check valve is provided at the suction port. The suction pipe is connected after the check valve.

[0006] Regarding the submersible pump described in the aforementioned literature, the applicant's research revealed that it does not possess a true non-backflow scavenging function. As shown in the accompanying diagrams of the aforementioned literature, when the hydraulic motor in the submersible pump is rotating, the centrifugal pump impeller is also constantly rotating. Oil is always present in the centrifugal pump casing channel and the connecting pipes. As long as the hydraulic motor is rotating, this oil cannot flow back out through the centrifugal pump impeller channel. However, as soon as the hydraulic motor stops rotating, the oil in the centrifugal pump casing channel and the connecting pipes will flow back out through the centrifugal pump impeller channel. Therefore, even if the oil in the tank is emptied by the self-priming pump impeller located below, once the hydraulic motor above stops rotating, causing the centrifugal pump impeller to also stop rotating, the oil in the centrifugal pump casing channel and the connecting pipes will flow back into the tank through the centrifugal pump impeller channel. Therefore, the applicant believes that the submersible pump in the aforementioned patent literature cannot achieve a true non-backflow scavenging function.

[0007] In summary, designing an integrated pumping and tank cleaning method for submersible pumps, enabling both pumping and cleaning to be performed simultaneously, facilitating convenient and quick oil unloading operations, reducing residual oil in tanks to minimize resource waste, lowering labor intensity for operators, and improving unloading efficiency are urgent technical problems that need to be solved. Summary of the Invention

[0008] The technical problem to be solved by the present invention is to address the deficiencies in the existing technology by providing an integrated pumping and tank cleaning method for a submersible pump. This method can realize pumping and tank cleaning functions in one go, making it convenient and quick to unload oil from the tank. It reduces the amount of residual oil in the tank, thereby reducing resource waste, reducing the labor intensity of operators, and improving the efficiency of unloading.

[0009] To solve the above-mentioned technical problems, the technical solution to be solved by the present invention is: an integrated operation method for pumping and sweeping of a submersible pump, which is to set up an inner pump with an internal oil suction pipe inside the submersible pump to form a pump-in-pump structure, and to use the submersible pump and the loading arm connected to it to form an external pumping channel A, and to use the inner pump and the internal oil suction pipe connected to it to form an internal pumping channel B, wherein the internal pumping channel B is located inside the external pumping channel A; During the pumping process, the external pumping channel A and the internal pumping channel B are used simultaneously to pump out the oil from the tank, completing the pumping operation. After all the oil in the tank has been pumped out, the internal pumping channel B is used to pump out the remaining oil in the submersible pump and a portion of the loading arm connected to it, completing the tank cleaning operation.

[0010] Preferably, during the liquid extraction process, the submersible pump and the internal pump operate simultaneously; after the liquid extraction is completed, the submersible pump and the internal pump continue to operate simultaneously to complete the tank cleaning process.

[0011] Preferably, the submersible pump includes a cylindrical pump body shell, and a pump head, a motor and a bottom volute are arranged sequentially from top to bottom inside the pump body shell. An annular channel is formed between the outer peripheral surface of the motor and the inner peripheral surface of the pump body shell. The inner cavity of the bottom volute is connected to the inner cavity of the pump head through the annular channel. The bottom opening of the bottom volute is an oil inlet C1, and the top opening of the pump head is an oil outlet D1. The top opening of the pump head is connected to the loading arm. An inner pump housing is also provided in the inner cavity of the pump head. The inner cavity of the inner pump housing is isolated from the inner cavity of the pump head. The inner pump includes an inner pump impeller, which is disposed in the inner cavity of the inner pump housing. A volute impeller is disposed in the inner cavity of the bottom volute. The motor shaft of the motor is hollow. Its upper end extends into the inner cavity of the pump head and is connected to the inner pump impeller. Its lower end extends into the inner cavity of the bottom volute and is connected to the volute impeller. The lower end of the hollow motor shaft is the inner pump oil inlet C2. The top opening of the inner pump housing is the inner pump oil outlet D2. The top opening of the inner pump housing is connected to the internal oil suction pipe. The inner cavities of the hollow motor shaft, the inner cavity of the inner pump housing, and the inner cavity of the internal oil suction pipe are sequentially connected to each other. The inner cavity of the bottom volute, the annular channel, the inner cavity of the pump head, and the loading arm communicating with the inner cavity of the pump head form an external liquid extraction channel A; the inner cavity of the hollow motor shaft, the inner cavity of the pump head, and the inner cavity of the internal oil suction pipe form an internal liquid extraction channel B.

[0012] Preferably, the simultaneous operation of the submersible pump and the internal pump is achieved by rotating the motor shaft, which drives the internal pump impeller and the volute impeller to rotate together.

[0013] Preferably, the specific steps of the integrated liquid extraction and scavenging operation method are as follows: I) Liquid extraction operation steps: When the operation begins and the oil in the tank is being pumped out, the motor is started, causing the motor shaft to drive the inner pump impeller and the volute impeller to rotate together. Due to the rotation of the volute impeller, a portion of the oil in the tank is drawn out through the external pumping channel A, that is, the oil in the tank is drawn in through the bottom opening of the bottom volute, and is drawn out sequentially through the inner cavity of the bottom volute, the annular channel, the inner cavity of the pump head, and the loading arm connected to the inner cavity of the pump head. Due to the rotation of the inner pump impeller, another portion of the oil in the tank is drawn out through the internal pumping channel B, that is, the oil in the tank is drawn in through the lower end of the hollow motor shaft, and is drawn out sequentially through the inner cavity of the hollow motor shaft, the inner cavity of the inner pump housing, and the inner cavity of the internal suction pipe. II. Steps for sweeping up inventory: After the oil in the tank is completely pumped out, the tank cleaning begins, keeping the inner pump impeller and the volute impeller rotating together. Due to the rotation of the volute impeller, the remaining oil will be retained in the submersible pump and a part of the loading arm connected to it. Due to the rotation of the inner pump impeller, the remaining oil in the submersible pump and a part of the loading arm connected to it will continue to be pumped out from the internal pumping channel B. That is, the remaining oil is sucked in from the lower end of the hollow motor shaft, and is pumped out in sequence through the inner cavity of the hollow motor shaft, the inner cavity of the inner pump housing, and the inner cavity of the internal oil suction pipe.

[0014] Preferably, a one-way valve is provided on the internal pumping channel B; after the sweeping operation is completed and the motor is turned off, the one-way valve is used to prevent the oil in the internal pumping channel B from flowing back into the oil tank.

[0015] Preferably, the one-way valve is located on the internal oil suction pipe and near the internal pump housing.

[0016] Preferably, the one-way valve is located on the motor shaft and above the inner pump oil inlet C2 at the lower end of the motor shaft.

[0017] Preferably, the submersible pump is also equipped with a detection device for detecting changes in the motor load, and the pumping and sweeping time is controlled by detecting changes in the motor load through the detection device.

[0018] The beneficial effects of this invention are as follows: By designing a pump-within-a-pump structure, this invention forms two pumping channels, one internal and one external. First, both channels simultaneously pump oil from the tank. When the oil in the tank is depleted, the internal pumping channel continues to pump out the oil remaining in the submersible pump and a portion of the loading arm connected to it, completing the tank cleaning process. This achieves both pumping and tank cleaning functions in one operation, enabling convenient and quick oil unloading operations. It reduces the amount of residual oil in the tank, thus reducing resource waste and lowering the labor intensity of operators, while improving unloading efficiency. Through specific structural design, a pump-within-a-pump design is achieved, forming two pumping channels, facilitating the pumping and tank cleaning functions of the submersible pump. A one-way valve on the internal pumping channel prevents oil from flowing back into the tank after the explosion-proof motor stops rotating. A detection device for monitoring motor load changes facilitates intelligent automatic control of the submersible pump's oil pumping and tank cleaning operation time. Attached Figure Description

[0019] Figure 1 This diagram illustrates the operation of using an existing submersible pump for liquid pumping. Figure 1 ; Figure 2 This diagram illustrates the operation of using an existing submersible pump for liquid pumping. Figure 2 ; Figure 3 This is a schematic diagram illustrating the principle of the integrated oil and tank cleaning operation method of the present invention. Figure 1 ; Figure 4 This is a schematic diagram illustrating the principle of the integrated oil and tank cleaning operation method of the present invention. Figure 2 ; Figure 5 This is a schematic diagram illustrating the principle of the integrated oil and tank cleaning operation method of the present invention. Figure 3 ; Figure 6 This is a schematic diagram of the axial cross-sectional structure of the submersible pump in Embodiment 1 of the present invention; Figure 7 This is a schematic diagram of an integrated oil and tank cleaning operation using the submersible pump in Embodiment 1 of the present invention; Figure 8 for Figure 7 A schematic diagram of the axial cross-section of a submersible pump during oil operations. Figure 9 for Figure 7 A schematic diagram of the axial cross-section of the submersible pump during tank cleaning operations. Figure 10 for Figure 6 A schematic diagram of a partial axial cross-section of the structure located at the pump head; Figure 11 for Figure 6 A schematic diagram of a partial axial cross-section of the structure located at the bottom vortex shell; Figure 12 This is a partial axial cross-sectional view of the submersible pump located at the bottom volute of the present invention, according to Embodiment 2 of the present invention. In the diagram: 1. Loading arm, 2. Oil tank, 211. Oil collection basin, 3. Submersible pump, 31. Pump body casing, 32. Pump head, 321. Inner pump casing, 322. Conduit, 33. Bottom volute, 331. Volute impeller, 34. Explosion-proof motor, 341. Motor shaft, 4. Oil, 5. Internal suction pipe, 6. Inner pump, 611. Inner pump impeller, 7. Annular channel, 8. Check valve, 9. Flange, 10. Opening, 11. Bottom ring, 12. Filter screen. Detailed Implementation

[0020] The submersible pump in this application is used in an integrated pumping and tank cleaning method, wherein the submersible pump employs a pump-within-a-pump structure design, such as... Figure 3 As shown, an inner pump 6 with an internal suction pipe 5 is installed inside the submersible pump 3, forming a pump-within-a-pump structure. The submersible pump 3 and the loading arm 1 connected to it form an external pumping channel A, and the inner pump 6 and the internal suction pipe 5 connected to it form an internal pumping channel B. The external pumping channel A and the internal pumping channel B are independently set up, and the internal pumping channel B is located inside the external pumping channel A. Figure 3 As shown, during pumping, first insert one end of the loading arm 1 equipped with the submersible pump 3 into the oil tank 2, place the submersible pump 3 into the oil collection basin 211 of the oil tank 2, and then turn on the submersible pump 3 and the internal pump 6. Simultaneously, using the external pumping channel A and the internal pumping channel B, the oil 4 in the oil tank 2 is pumped out. Figure 4 and Figure 5As shown, after all the oil 4 in tank 2 has been pumped out, the submersible pump 3 and the internal pump 6 are kept running simultaneously. The internal pump 6 is used to pump out the remaining oil 4 in the submersible pump 3 and a portion of the loading arm 1 connected to it, completing the tank cleaning work. This application designs a pump-within-a-pump structure to form two pumping channels, internal and external. First, the two pumping channels are used simultaneously to pump the oil from the tank. When the oil in the tank is completely pumped out, the internal pumping channel is used to continue pumping out the oil remaining in the submersible pump and a portion of the loading arm connected to it, completing the tank cleaning work. Thus, the pumping and tank cleaning functions are achieved in one go, enabling convenient and quick oil unloading operations. This reduces the amount of residual oil in the tank, thereby reducing resource waste, lowering the labor intensity of operators, and improving the efficiency of oil unloading.

[0021] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0022] Example 1: As Figure 6 As shown, the submersible pump 3 includes a cylindrical pump body shell 31, a pump head 32 disposed inside the pump body shell 31 and located at the upper position, a bottom volute 33 disposed inside the pump body shell 31 and located at the lower position, and an explosion-proof motor 34 disposed between the upper chamber 32 and the bottom volute 33. The explosion-proof motor 34 is cylindrical, and its outer circumferential surface forms an annular channel 7 with the inner circumferential surface of the pump body shell 31. The inner cavity of the bottom volute 33 is connected to the inner cavity of the pump head 32 through the annular channel 7. The bottom opening of the bottom volute 33 is an oil suction port C1, and the top opening of the pump head 32 is an oil discharge port D1. The top opening of the pump head 32 is connected to the loading arm 1. In this way, the inner cavity of the bottom volute 33, the annular channel 7, the inner cavity of the pump head 32, and the loading arm 1 connected to the inner cavity of the pump head 32 form an external pumping channel A.

[0023] An inner pump housing 321 is also provided in the inner cavity of the pump head 32. The inner cavity of the inner pump housing 321 is isolated from the inner cavity of the pump head 32. The inner pump includes an inner pump impeller 611, which is disposed in the inner cavity of the inner pump housing 321. A volute impeller 331 is disposed in the inner cavity of the bottom volute 33. The motor shaft 341 of the explosion-proof motor 34 is hollow with open ends. Its upper end extends into the inner cavity of the pump head 32 and is connected to the inner pump impeller 611. Its lower end extends into the inner cavity of the bottom volute 33 and is connected to the volute impeller 331. Thus, the rotation of the motor shaft 341 can drive the inner pump impeller 611 and the volute impeller 331 to rotate together. The lower end of the hollow motor shaft 341 is the oil inlet C2 of the internal pump. The inner cavity of the bottom volute 33 is connected to the inner cavity of the internal pump housing 321 through the inner cavity of the hollow motor shaft 341. The top opening of the internal pump housing 321 is the oil outlet D2 of the internal pump. The top opening of the internal pump housing 321 is connected to the internal oil suction pipe 5. The inner cavities of the hollow motor shaft 341, the internal pump housing 321, and the internal oil suction pipe 5 are sequentially interconnected, thus forming an internal liquid extraction channel B.

[0024] Through the above method, a pump-within-a-pump design was completed, forming two pumping channels, one internal and one external, which facilitates the pumping and scavenging functions of the submersible pump. Furthermore, since the internal space of the entire submersible pump is limited, in order to integrate the pumping and scavenging functions, the applicant used a single motor shaft to drive two impellers to rotate together. This allows for the integrated design of pumping and scavenging functions within a limited space.

[0025] Work begins; when the oil is being drawn from the tank, such as... Figure 7 and Figure 8 As shown, when the explosion-proof motor 34 is started, the motor shaft 341 drives the inner pump impeller 611 and the volute impeller 331 to rotate together. Due to the rotation of the volute impeller 331, a portion of the oil in the oil tank is drawn out from the external pumping channel A. That is, the oil in the oil tank 2 is sucked in from the bottom opening of the bottom volute 33, and is drawn out sequentially through the inner cavity of the bottom volute 33, the annular channel 7, the inner cavity of the pump head 32, and the loading arm 1 connected to the inner cavity of the pump head 32 (the path is shown by the solid arrow in the figure). Due to the rotation of the inner pump impeller 611, another portion of the oil in the oil tank is drawn out from the internal pumping channel B. That is, the oil in the oil tank 2 is sucked in from the lower end of the hollow motor shaft 341, and is drawn out sequentially through the inner cavity of the hollow motor shaft 341, the inner cavity of the inner pump housing 321, and the inner cavity of the internal oil suction pipe 5 (the path is shown by the dashed arrow in the figure).

[0026] After the oil in the tank is completely pumped out, the tank cleaning begins. When pumping out the remaining oil 4 in the submersible pump 3 and a portion of the loading arm 1 connected to it, the residual oil is retained within the submersible pump 3 and the connected loading arm 1 due to the rotation of the volute impeller 331, preventing it from flowing back into the tank 2. At this time, due to the rotation of the inner pump impeller 611, the remaining oil 4 in the submersible pump 3 and the connected loading arm 1 continues to be drawn out from the internal pumping channel B. That is, the residual oil is sucked in from the lower end of the hollow motor shaft 341, and sequentially drawn out through the inner cavity of the hollow motor shaft 341, the inner cavity of the inner pump housing 321, and the inner cavity of the internal suction pipe 5 (the path is shown by the dotted arrow in the figure). This completes the pumping and tank cleaning operations in one operation.

[0027] like Figure 5 and Figure 9 As shown, one end of the internal oil suction pipe 5 is connected to the top opening of the internal pump housing 321, and the other end of the internal oil suction pipe 5 passes through the highest position F of the loading arm 1 and is installed downward along the loading arm 1 in the inner cavity of the loading arm 1. The internal oil suction pipe 5 can be a plastic hose or a rubber hose.

[0028] like Figure 9 As shown, in order to prevent the oil in the internal suction pipe 5 from flowing back into the oil tank 2 after the explosion-proof motor 34 stops rotating, a one-way valve 8 is installed on the internal suction pipe 5. The one-way valve 8 is located close to the inner pump housing 321. The oil can flow from the inner pump housing 321 to the internal suction pipe 5 through the one-way valve 8, but cannot flow back from the internal suction pipe 5 to the inner pump housing 321 through the one-way valve 8. This avoids the oil in the internal suction pipe 5 from flowing back into the oil tank 2 after the explosion-proof motor 34 stops rotating.

[0029] To facilitate intelligent control, a detection device (not shown in the figure) is also installed in the submersible pump to detect changes in motor load. This device controls the pumping and tank cleaning times based on the changes in motor load. Since the motor load is high when both external pumping channel A and internal pumping channel B are used simultaneously for pumping, and low when internal pumping channel B is used for tank cleaning, the timing of oil pumping and tank cleaning operations can be automatically controlled by detecting changes in motor load.

[0030] like Figure 10As shown, the pump head 32 is cylindrical, and a connecting flange 9 is provided on the outer circumferential surface of its top opening. The connecting flange 9 connects to the flange on the loading arm 1, thereby connecting the top opening of the pump head 32 to the loading arm 1. A communication port (not shown in the figure) is provided on the side of the pump head 32, and an annular channel 7 communicates with the communication port, thereby connecting the annular channel 7 to the inner cavity of the pump head 32. The inner pump housing 321 is located in the inner cavity of the pump head 32 at the lower position. A conduit 322 is also provided in the inner cavity of the pump head 32 at one side, through which the wires of the explosion-proof motor 34 are led out to the outside of the submersible pump.

[0031] like Figure 11 As shown, an opening 10 is formed on the lower side of the hollow motor shaft 341, near the impeller 331 of the volute casing. This opening serves as the internal pump oil inlet C2. Positioning the internal pump oil inlet C2 on the side of the motor shaft facilitates oil extraction. A bottom ring 11 is provided at the bottom of the pump housing 31, and a filter screen 12 is installed inside the bottom ring 11. The filter screen 12 is located below the bottom opening of the bottom volute casing 33. This ensures that the pumped oil is filtered by the filter screen 12 before entering the bottom opening of the bottom volute casing 33, preventing impurities from being sucked into the volute casing and damaging the submersible pump, thus extending its service life.

[0032] Example 2: Figure 12 As shown, the difference compared to Embodiment 1 is that the one-way valve 8 is not located on the internal oil suction pipe 5, but rather on the motor shaft 341 and above the opening 10. This downward adjustment of the one-way valve 8 further prevents the oil in the internal oil suction pipe 5 from flowing back into the oil tank 2 after the explosion-proof motor 34 stops rotating.

[0033] In summary, this invention, through the design of a pump-within-a-pump structure, forms two pumping channels, one internal and one external. First, both channels simultaneously pump oil from the tank. Once the oil in the tank is depleted, the internal channel continues to pump out the remaining oil from the submersible pump and a portion of the loading arm connected to it, completing the tank cleaning process. This achieves both pumping and cleaning functions in one operation, enabling convenient and quick oil unloading. It reduces the amount of residual oil in the tank, minimizing resource waste, lowering the workload for operators, and improving unloading efficiency. The specific structural design completes the pump-within-a-pump scheme, forming two pumping channels, facilitating the pumping and cleaning functions of the submersible pump. A one-way valve in the internal pumping channel prevents oil from flowing back into the tank after the explosion-proof motor stops rotating. A detection device for monitoring motor load changes allows for intelligent automatic control of the submersible pump's oil pumping and cleaning time.

[0034] In this embodiment, "multiple" refers to "two or more". The above embodiments are for illustrative purposes only and are not intended to limit the invention. Those skilled in the art can make various changes or modifications without departing from the spirit and scope of the invention. Therefore, all equivalent technical solutions should also fall within the protection scope of this invention, which is defined by the claims.

Claims

1. A method for integrating pumping and tank sweeping operations with a submersible pump, characterized in that: It is a pump-within-a-pump structure with an internal suction pipe installed inside the submersible pump. The submersible pump and the loading arm connected to it form an external pumping channel A, and the internal pump and the internal suction pipe connected to it form an internal pumping channel B. The internal pumping channel B is located inside the external pumping channel A. During the pumping process, the oil in the tank is pumped out simultaneously using both the external pumping channel A and the internal pumping channel B to complete the pumping operation. After all the oil in the tank has been pumped out, the remaining oil in the submersible pump and part of the loading arm connected to it is pumped out through the internal pumping channel B to complete the tank cleaning work. During the pumping operation, the submersible pump and the internal pump work simultaneously; after the pumping operation is completed, the submersible pump and the internal pump continue to work simultaneously to complete the tank cleaning operation. The submersible pump includes a cylindrical pump body shell. Inside the pump body shell, a pump head, a motor, and a bottom volute are arranged sequentially from top to bottom. An annular channel is formed between the outer circumferential surface of the motor and the inner circumferential surface of the pump body shell. The inner cavity of the bottom volute is connected to the inner cavity of the pump head through the annular channel. The bottom opening of the bottom volute is the oil inlet C1, and the top opening of the pump head is the oil outlet D1. The top opening of the pump head is connected to the loading arm. An inner pump housing is also provided in the inner cavity of the pump head. The inner cavity of the inner pump housing is isolated from the inner cavity of the pump head. The inner pump includes an inner pump impeller, which is disposed in the inner cavity of the inner pump housing. A volute impeller is disposed in the inner cavity of the bottom volute. The motor shaft of the motor is hollow. Its upper end extends into the inner cavity of the pump head and is connected to the inner pump impeller. Its lower end extends into the inner cavity of the bottom volute and is connected to the volute impeller. The lower end of the hollow motor shaft is the inner pump oil inlet C2. The top opening of the inner pump housing is the inner pump oil outlet D2. The top opening of the inner pump housing is connected to the internal oil suction pipe. The inner cavities of the hollow motor shaft, the inner cavity of the inner pump housing, and the inner cavity of the internal oil suction pipe are sequentially connected to each other. The inner cavity of the bottom volute, the annular channel, the inner cavity of the pump head, and the loading arm communicating with the inner cavity of the pump head form an external liquid extraction channel A; the inner cavity of the hollow motor shaft, the inner cavity of the pump head, and the inner cavity of the internal oil suction pipe form an internal liquid extraction channel B.

2. The integrated liquid extraction and scavenging operation method according to claim 1, characterized in that: The simultaneous operation of the submersible pump and the internal pump is achieved by rotating the motor shaft, which drives the impeller of the internal pump and the volute impeller to rotate together.

3. The integrated liquid extraction and silo cleaning method according to claim 1, characterized in that: The specific steps of the integrated liquid extraction and silo sweeping operation method are as follows: I) Liquid extraction operation steps: When the operation begins and the oil in the tank is being pumped out, the motor is started, causing the motor shaft to drive the inner pump impeller and the volute impeller to rotate together. Due to the rotation of the volute impeller, a portion of the oil in the tank is drawn out through the external pumping channel A, that is, the oil in the tank is drawn in through the bottom opening of the bottom volute, and is drawn out sequentially through the inner cavity of the bottom volute, the annular channel, the inner cavity of the pump head, and the loading arm connected to the inner cavity of the pump head. Due to the rotation of the inner pump impeller, another portion of the oil in the tank is drawn out through the internal pumping channel B, that is, the oil in the tank is drawn in through the lower end of the hollow motor shaft, and is drawn out sequentially through the inner cavity of the hollow motor shaft, the inner cavity of the inner pump housing, and the inner cavity of the internal suction pipe. II. Steps for sweeping up inventory: After the oil in the tank is completely pumped out, the tank cleaning begins, keeping the inner pump impeller and the volute impeller rotating together. Due to the rotation of the volute impeller, the remaining oil will be retained in the submersible pump and a part of the loading arm connected to it. Due to the rotation of the inner pump impeller, the remaining oil in the submersible pump and a part of the loading arm connected to it will continue to be pumped out from the internal pumping channel B. That is, the remaining oil is sucked in from the lower end of the hollow motor shaft, and is pumped out in sequence through the inner cavity of the hollow motor shaft, the inner cavity of the inner pump housing, and the inner cavity of the internal oil suction pipe.

4. The integrated liquid extraction and silo cleaning method according to claim 3, characterized in that: A one-way valve is installed on the internal pumping channel B; after the sweeping operation is completed and the motor is turned off, the one-way valve is used to prevent the oil in the internal pumping channel B from flowing back into the oil tank.

5. The integrated liquid extraction and scavenging operation method according to claim 4, characterized in that: The one-way valve is located on the internal oil suction pipe and near the internal pump housing.

6. The integrated liquid extraction and scavenging operation method according to claim 4, characterized in that: The one-way valve is installed on the motor shaft and located above the internal pump oil inlet C2 at the lower end of the motor shaft.

7. The integrated liquid extraction and scavenging operation method according to claim 3, characterized in that: The submersible pump is also equipped with a detection device for detecting changes in the motor load. The pumping and tank cleaning times are controlled by detecting changes in the motor load through the detection device.

Images