A self-cooling circulating sewage pump with adjustable pressure for motor inner cavity circulating cooling system

Abstract

The utility model discloses a kind of motor inner cavity circulating cooling system pressure adjustable self-cooling circulating sewage pumps, it is related to pump product, to solve the problem that traditional self-cooling circulating sewage pump is caused by cooling liquid thermal expansion and contraction and cooling cavity pressure is too large, mechanical seal is easy to fail leakage, and cooling liquid is easy to contact oxidation with air;The sewage pump includes motor, outer sleeve, cooling cavity, circulating impeller, pump cover, mechanical seal and pressure stabilizing tank;Among them, pressure stabilizing tank is connected with outer sleeve and communicates cooling cavity, its inside is separated into air cavity and liquid cavity by flexible airbag, air cavity can be pre-filled with gas close to system normal working pressure, and pressure stabilizing tank is equipped with pressure gauge, air inlet, fixed sling bag device and sealingly connected water inlet pipe and connecting pipe;Without modifying original pump structure, the volume of pressure stabilizing tank can be flexibly adapted according to motor model, guaranteeing pump long-term stable operation, applicable to pressure regulation and cooling scene of self-cooling circulating sewage pump.

Description

Technical Field

[0001] This utility model relates to pump products, specifically a self-cooling circulating sewage pump with adjustable pressure in the internal circulation cooling system of an electric motor. Background Technology

[0002] Currently, traditional submersible motors can only operate underwater, while traditional standard motors can only be dry-installed and cannot operate underwater. This led to the development of self-cooled circulating submersible motors. In these motors, the internal coolant circulates via a circulating impeller, generating heat at the pump cover of the self-cooling pump. This heat is then continuously carried away from the motor, cooling it. However, as the motor's temperature rises during operation, the coolant expands, causing excessive pressure in the cooling chamber. Because the mechanical seal has weak back pressure resistance, it can easily be pushed out, leading to coolant leakage and the entry of sewage and debris into the cooling chamber. This can prevent the motor from cooling properly and may even cause it to burn out.

[0003] Therefore, a device is needed to adjust the pressure of the cooling chamber of a self-cooling circulating motor, and it is also necessary to consider that the coolant in the motor cooling chamber should not come into direct contact with the external environment to prevent the coolant from oxidizing and reducing the cooling effect. Utility Model Content

[0004] The purpose of this invention is to provide a self-cooling circulating sewage pump with an adjustable pressure in the internal cooling system of a motor cavity. It features a design with a pressure-stabilizing tank, which includes an air chamber and a liquid chamber separated by a closed, flexible airbag. This tank is attached to the outer sleeve of the motor as a "temporary air tank." When the coolant heats up and expands, it inflates the airbag, converting excess pressure potential energy within the system into the elastic potential energy of the gas and storing it. This rapidly absorbs pressure peaks and prevents coolant leakage due to overpressure failure of the mechanical seal. This solves the problem of excessive internal pressure leading to mechanical seal leakage caused by the expansion of the motor cooling chamber as the temperature rises in the self-cooling circulating sewage pump motor.

[0005] To achieve the above objectives, this utility model provides the following technical solution: A self-cooling circulating sewage pump with adjustable pressure in its internal motor cavity cooling system includes a motor, an outer sleeve fitted over the outside of the motor, a cooling cavity formed between the motor and the outer sleeve, a circulating impeller located at one end of the motor, a pump cover cooperating with the circulating impeller, and a mechanical seal located between the pump cover and the motor. The pump is characterized by further including a pressure stabilizing tank, which is connected to the outer sleeve and communicates with the cooling cavity. The pressure stabilizing tank contains a flexible air bladder that divides the interior of the pressure stabilizing tank into a gas cavity and a liquid cavity. The liquid cavity communicates with the cooling cavity, and the gas cavity stores gas to buffer pressure fluctuations within the cooling cavity.

[0006] The outer wall of the pressure stabilizing tank is provided with a nameplate seat, a pressure gauge and an air inlet. The air inlet is connected to the air chamber and the pressure gauge is used to monitor the pressure of the air chamber.

[0007] The pressure stabilizing tank is equipped with a fixed lifting device, which is connected to the flexible airbag and is used to limit the range of movement of the flexible airbag within the pressure stabilizing tank.

[0008] The pressure stabilizing tank is equipped with a water inlet pipe and a connecting pipe. One end of the water inlet pipe is connected to the liquid chamber, and the other end is sealed to the outer sleeve through the connecting pipe, so as to achieve sealed communication between the liquid chamber and the cooling chamber.

[0009] In the initial state, the gas pressure pre-charged into the air chamber is consistent with the normal operating pressure of the cooling circulation system corresponding to the cooling chamber. At this time, the flexible airbag is in a force balance position, and there is no cooling medium remaining in the liquid chamber.

[0010] The flexible airbag is a sealed elastic structure that isolates the gas in the air chamber from the cooling medium in the liquid chamber and prevents the cooling medium from contacting the outside air.

[0011] The volume of the pressure stabilizing tank is adapted according to the model of the motor and the expansion volume of the cooling medium in the cooling chamber.

[0012] The pressure regulation and cooling functions of this sewage pump are achieved through the dynamic coordination of the motor, cooling chamber, circulating impeller, pressure stabilizing tank, and flexible airbag, as detailed below: In the initial state, gas close to the normal operating pressure of the cooling circulation system is pre-charged into the gas chamber through the gas inlet of the pressure stabilizing tank. At this time, the flexible airbag is in a force balance position within the range limited by the fixed airbag device. There is no cooling medium left in the liquid chamber of the pressure stabilizing tank. The pressure gauge monitors the initial pressure of the gas chamber in real time to ensure that the system is in a ready-to-operate state.

[0013] When the motor starts, the circulating impeller rotates synchronously, driving the cooling medium in the cooling chamber to circulate along the cooling chamber → pump cover → cooling chamber. During this process, it continuously absorbs the heat generated by the motor operation, realizing the motor's self-cooling. As the running time increases, the cooling medium expands in volume due to heat absorption, resulting in a passive increase in pressure inside the cooling chamber.

[0014] When the pressure in the cooling chamber exceeds the pre-charge pressure of the pressure stabilizing tank's gas chamber, the high-pressure cooling medium enters the liquid chamber of the pressure stabilizing tank through the connecting pipe between the outer sleeve and the pressure stabilizing tank and the water inlet pipe, generating a thrust on the flexible airbag. Under the action of the thrust, the flexible airbag is compressed towards the gas chamber side, the gas chamber volume shrinks, and the internal gas pressure rises simultaneously. During this process, the flexible airbag converts the pressure potential energy of the cooling medium into the elastic potential energy of the gas in the gas chamber, quickly absorbing the pressure peak of the cooling chamber and avoiding the pressure from acting directly on the mechanical seal.

[0015] When the pressure in the air chamber rises to a point where it rebalances with the pressure in the cooling chamber, the cooling medium stops flowing into the liquid chamber, and the flexible airbag maintains its current compressed state. If the motor load changes, causing the temperature of the cooling medium to drop and its volume to shrink, the pressure in the cooling chamber to decrease. The high-pressure gas in the air chamber then pushes the flexible airbag to reset, pressing the cooling medium in the liquid chamber back into the cooling chamber, thus achieving pressure balance again.

[0016] Throughout the entire operation, the pressure stabilizing tank continuously buffers the pressure fluctuations in the cooling chamber caused by the thermal expansion and contraction of the medium through dynamic adjustment driven by pressure difference, airbag deformation, and gas-liquid pressure rebalancing. At the same time, the airtight structure of the flexible airbag isolates the gas in the air chamber from the cooling medium, preventing the cooling medium from contacting and oxidizing with the outside air. The circulating impeller ensures continuous circulation and heat dissipation of the cooling medium. The two work together to maintain stable cooling of the motor and prevent leakage of the cooling medium caused by overpressure failure of the mechanical seal, ultimately achieving long-term stable operation of the pump.

[0017] Compared with the prior art, the beneficial effects of this utility model are: 1. Traditional self-cooled sewage pumps experience a continuous increase in pressure within the cooling chamber due to the thermal expansion and contraction of the cooling medium as the motor operates. The mechanical seal, with its weak back pressure capability, is easily pushed out by high pressure, leading to coolant leakage and the entry of sewage and debris into the cooling chamber. Ultimately, this results in the motor failing to cool or even burning out. This invention utilizes the dynamic synergy of a pressure stabilizing tank and a flexible airbag to buffer pressure fluctuations through a "gas-liquid energy conversion" method. When the cooling chamber pressure rises, the flexible airbag compresses the air chamber to absorb the pressure peak; when the pressure decreases, the gas in the air chamber pushes the airbag to force the medium back into the cooling chamber. This consistently prevents direct pressure on the mechanical seal, fundamentally reducing the probability of seal failure and medium leakage, and extending the service life of the motor and pump body.

[0018] 2. Existing technologies do not isolate and protect the cooling medium, making the coolant susceptible to oxidation upon contact with outside air. This leads to a decline in cooling performance over time, indirectly increasing the risk of motor overheating. While some improved solutions attempt to seal the cooling medium, they require modifications to the core pump structure, resulting in poor compatibility. The flexible airbag in this invention is a sealed, elastic structure that completely separates the gas chamber and liquid chamber of the pressure stabilizing tank. This prevents the gas in the gas chamber from mixing with the coolant and avoids contact between the coolant and outside air, effectively preventing coolant oxidation and deterioration. This ensures that cooling efficiency does not decrease during long-term operation, eliminating the need for frequent coolant replacements and reducing maintenance costs.

[0019] 3. Traditional pressure regulation solutions often require redesigning or modifying core components such as the pump's cooling chamber and outer sleeve. This not only involves complex disassembly and assembly but also necessitates custom-designed structures for different motor models, resulting in poor compatibility and high production costs. The pressure stabilizing tank of this invention is directly and sealed to the original pump's outer sleeve via a connecting pipe, eliminating the need to modify existing components such as the motor, circulating impeller, and pump cover, simplifying disassembly and assembly. Furthermore, pressure stabilizing tanks of different volumes can be flexibly selected based on the motor model and the expansion volume of the cooling medium, eliminating the need to replace the entire pump body and significantly reducing equipment adaptation and subsequent maintenance costs.

[0020] 4. In existing technologies, "motor cooling" and "pressure control" are mostly independent functions. The circulating cooling medium is only responsible for heat dissipation and lacks real-time response to pressure fluctuations. This easily leads to the contradiction of "effective heat dissipation but pressure overpressure," causing the pump to be unable to operate continuously and stably. This utility model deeply integrates "circulating impeller driving medium heat dissipation" and "dynamic pressure regulation by the pressure stabilizing tank": the circulating impeller ensures that the cooling medium continuously absorbs heat, while the pressure stabilizing tank synchronously buffers pressure fluctuations caused by the thermal expansion and contraction of the medium. The two form a "heat dissipation-pressure regulation" closed loop, which not only ensures that the motor is always in a safe cooling state, but also avoids the impact of pressure fluctuations on key components, ultimately achieving long-term continuous and stable operation of the pump, which is especially suitable for high-load and long-term operation scenarios. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of a self-cooling circulating sewage pump with adjustable pressure in the internal cavity cooling system of an electric motor, according to this utility model. Figure 2 This is a schematic diagram of the pressure stabilizing tank structure of a self-cooling circulating sewage pump with adjustable pressure in the internal cavity cooling system of an electric motor, according to this utility model. In the diagram: 1. Pressure stabilizing tank; 2. Outer sleeve; 3. Cooling chamber; 4. Motor; 5. Circulating impeller; 6. Pump cover; 7. Mechanical seal; 11. Nameplate holder; 12. Pressure gauge; 13. Air inlet; 14. Water inlet pipe; 15. Fixed suspension device; 16. Airbag; 17. Connecting pipe; 18. Air chamber; 19. Liquid chamber. Detailed Implementation

[0022] The technical solutions of the present invention will now be described in detail with reference to the accompanying drawings of the embodiments.

[0023] like Figure 1-2As shown, a self-cooling circulating sewage pump with adjustable pressure in the internal circulation cooling system of an electric motor includes a motor 4, an outer sleeve 2 sleeved on the outside of the motor 4, a cooling cavity 3 formed between the motor 4 and the outer sleeve 2, a circulating impeller 5 disposed at one end of the motor 4, a pump cover 6 cooperating with the circulating impeller 5, and a mechanical seal 7 disposed between the pump cover 6 and the motor 4. The pump is characterized by further including a pressure stabilizing tank 1, which is connected to the outer sleeve 2 and communicates with the cooling cavity 3. The pressure stabilizing tank 1 has a flexible air bladder 16 inside, which divides the interior of the pressure stabilizing tank 1 into a gas chamber and a liquid chamber. The liquid chamber communicates with the cooling cavity 3, and the gas chamber is used to store gas to buffer pressure fluctuations within the cooling cavity 3.

[0024] The outer wall of the pressure stabilizing tank 1 is provided with a nameplate seat 11, a pressure gauge 12 and an air inlet 13. The air inlet 13 is connected to the air chamber, and the pressure gauge 12 is used to monitor the pressure of the air chamber.

[0025] The pressure stabilizing tank 1 is equipped with a fixed lifting device 15, which is connected to the flexible airbag 16 and is used to limit the range of movement of the flexible airbag 16 within the pressure stabilizing tank 1.

[0026] The pressure stabilizing tank 1 is equipped with a water inlet pipe 14 and a connecting pipe 17. One end of the water inlet pipe 14 is connected to the liquid chamber, and the other end is sealed to the outer sleeve 2 through the connecting pipe 17, so as to achieve a sealed connection between the liquid chamber and the cooling chamber 3.

[0027] In the initial state, the gas pressure pre-charged into the air chamber is consistent with the normal operating pressure of the cooling circulation system corresponding to the cooling chamber 3. At this time, the flexible airbag 16 is in a force balance position, and there is no cooling medium remaining in the liquid chamber.

[0028] The flexible airbag 16 is a sealed elastic structure that isolates the gas in the air chamber from the cooling medium in the liquid chamber and prevents the cooling medium from contacting the outside air.

[0029] The volume of the pressure stabilizing tank 1 is adapted according to the model of the motor 4 and the expansion volume of the cooling medium in the cooling chamber 3.

[0030] Initially, the pressure stabilizing tank is pre-charged to a pressure close to the "normal operating" pressure of the cooling circulation system. At this time, the inner bladder diaphragm is in an equilibrium position, and there is no medium stored in the liquid chamber. As the heat dissipation increases after the motor starts running, the temperature of the cooling medium rises and it expands, passively increasing the pressure of the circulation system. When this pressure exceeds the pre-charge pressure of the pressure stabilizing tank, the high-pressure cooling medium in the motor cavity is forced into the liquid chamber of the pressure stabilizing tank, pushing the bladder diaphragm to compress the air chamber; the volume of the air chamber decreases, and the internal pressure increases until the air chamber pressure and the system pressure are rebalanced. The pressure stabilizing tank achieves dynamic balance of the circulating pressure in the motor cavity through "pressure difference-driven gas-liquid energy conversion," ensuring long-term stable operation of the pump.

Claims

1. A self-cooling circulating sewage pump with adjustable pressure for an internal circulating cooling system of an electric motor, comprising a motor (4), an outer sleeve (2) sleeved on the outside of the motor (4), a cooling cavity (3) formed between the motor (4) and the outer sleeve (2), a circulating impeller (5) disposed at one end of the motor (4), a pump cover (6) cooperating with the circulating impeller (5), and a mechanical seal (7) disposed between the pump cover (6) and the motor (4), characterized in that, It also includes a pressure stabilizing tank (1), which is connected to the outer sleeve (2) and communicates with the cooling chamber (3); the pressure stabilizing tank (1) is provided with a flexible airbag (16) inside, which divides the inside of the pressure stabilizing tank (1) into a gas chamber and a liquid chamber, the liquid chamber is communicated with the cooling chamber (3), and the gas chamber is used to store gas to buffer the pressure fluctuations in the cooling chamber (3).

2. The self-cooling circulating sewage pump with adjustable pressure in the motor cavity circulating cooling system according to claim 1, characterized in that, The outer wall of the pressure stabilizing tank (1) is provided with a nameplate seat (11), a pressure gauge (12) and an air inlet (13). The air inlet (13) is connected to the air chamber, and the pressure gauge (12) is used to monitor the pressure of the air chamber.

3. A self-cooling circulating sewage pump with adjustable pressure in the internal cooling system of a motor cavity, as described in claim 1 or 2, characterized in that, The pressure stabilizing tank (1) is equipped with a fixed lifting device (15), which is connected to the flexible airbag (16) and is used to limit the range of movement of the flexible airbag (16) within the pressure stabilizing tank (1).

4. The self-cooling circulating sewage pump with adjustable pressure in the motor cavity circulating cooling system according to claim 1, characterized in that, The pressure stabilizing tank (1) is provided with a water inlet pipe (14) and a connecting pipe (17). One end of the water inlet pipe (14) is connected to the liquid chamber, and the other end is sealed to the outer sleeve (2) through the connecting pipe (17) to achieve sealed communication between the liquid chamber and the cooling chamber (3).

5. A self-cooling circulating sewage pump with adjustable pressure in an internal cooling system for an electric motor, as described in claim 1, is characterized in that... In the initial state, the gas pressure pre-charged into the air chamber is consistent with the normal working pressure of the cooling circulation system corresponding to the cooling chamber (3). At this time, the flexible airbag (16) is in a force balance position, and there is no cooling medium remaining in the liquid chamber.

6. A self-cooling circulating sewage pump with adjustable pressure in an internal cooling system for an electric motor, as described in claim 1, is characterized in that... The flexible airbag (16) is a closed elastic structure that isolates the gas in the air chamber from the cooling medium in the liquid chamber and prevents the cooling medium from contacting the outside air.

7. A self-cooling circulating sewage pump with adjustable pressure in an internal cooling system for an electric motor, as described in claim 1, is characterized in that... The volume of the pressure stabilizing tank (1) is adapted according to the model of the motor (4) and the expansion volume of the cooling medium in the cooling chamber (3).

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