A negative pressure system for eliminating oil leakage of a large power motor and a use method thereof

Abstract

This invention belongs to the field of electric motor technology and provides a negative pressure system and method for eliminating oil leakage from the bearings of high-power electric motors. The system includes a control power supply box, an electric oil mist extractor, an oil-gas separator, an oil reservoir, air ducts, and a manual valve. The control power supply box is interlocked with the electric oil mist extractor. The outlet of the electric oil mist extractor is connected via air ducts to the balance air duct inlets on the drive side and the free side of the motor. The outlets on the drive side and free side of the motor are connected to the oil-gas separator via air ducts. The oil circuit of the oil-gas separator is connected to the oil reservoir, and the air circuit of the oil-gas separator is connected to the inlet of the electric oil mist extractor. The system uses the electric oil mist extractor to create a convection channel between the air ducts and the balance airflow chamber of the motor bearings, reducing the flow of oil mist into the motor through the air gap and effectively preventing oil mist from adhering to the coil surface. This prevents oil mist and dust in the air from corroding the coil insulation and affecting the main insulation of the motor coil.

Description

Technical Field

[0001] This invention belongs to the field of electric motor technology and relates to oil mist leakage in electric motor bearings, specifically a system and method for eliminating oil leakage in the bearings of high-power electric motors. Background Technology

[0002] High-power, high-voltage motors are typically used in blast furnace blowers at ironmaking plants. The motor's bearing cavity seals and the skeleton oil seals are hard resin seals that form a seal between the motor and the main shaft. During production, varying degrees of oil leakage frequently occur. Maintenance typically involves replacing the skeleton oil seals and spring rings, and replacing the cotton and linen packing seals on the outer retaining wall of the bearing with rubber strips. While this reduces leakage somewhat, some seepage still occurs. Adjusting the negative pressure of the oil mist fan at the lubrication station to reduce the negative pressure in the upper cavity of the oil tank and decrease the impact of vaporized oil mist on the retaining wall seals also proves insufficient; oil droplets still leak around the bearings on both the drive and free sides of the motor. This persistent oil leakage hinders the operation and management of high-power motors and poses a safety hazard to the operation of the high-voltage motor's electromagnetic coils. Summary of the Invention

[0003] The purpose of this invention is to provide a negative pressure system and method for eliminating oil leakage from the bearings of high-power motors, thereby solving the problem of oil leakage from the bearings of high-power motors.

[0004] The technical solution adopted by the present invention to achieve the above objectives is as follows:

[0005] A negative pressure system for eliminating oil leakage from the bearings of high-power electric motors includes: a control power supply box, an electric oil mist fan, an oil-gas separator, an oil reservoir, air ducts, and a manual valve. The control power supply box is interlocked with the operating signals of the electric oil mist fan and the main process system motor oil pump. The outlet of the electric oil mist fan is connected to the inlet of the balanced air duct on the drive side of the motor and the inlet of the balanced air duct on the free side of the motor via the air ducts. The outlet of the balanced air duct on the drive side of the motor and the outlet of the balanced air duct on the free side of the motor are connected to the oil-gas separator via air ducts. The oil circuit of the oil-gas separator is connected to the oil reservoir, and the air circuit of the oil-gas separator is connected to the inlet of the electric oil mist fan.

[0006] Furthermore, the manual valves include an air exhaust regulating manual valve installed in the air duct of the electric oil mist fan outlet, a drive-side positive pressure regulating manual valve installed in the air duct of the motor drive-side balance air duct inlet, a free-side positive pressure regulating manual valve installed in the air duct of the balance air duct inlet on the free side of the motor, a drive-side negative pressure regulating manual valve installed in the air duct of the motor drive-side balance air duct outlet, a free-side negative pressure regulating manual valve installed in the air duct outlet of the balance air duct on the free side of the motor, and a negative pressure overall regulating manual valve installed in the air inlet of the oil-gas separator.

[0007] Furthermore, the air inlet of the motor drive-side balance air duct, the air inlet of the motor free-side balance air duct, the air outlet of the motor drive-side balance air duct, and the air outlet of the motor free-side balance air duct are respectively connected to the air duct pipeline using spring tube PVC pipe.

[0008] A method for using a negative pressure system to eliminate oil leakage from the bearings of high-power electric motors includes:

[0009] S1. Use an electric oil mist fan to form a convection channel between the air duct and the balance airflow chamber of the motor bearing, so as to equalize the airflow pressure in the breathing equalization chamber of the motor bearing to the airflow that is slightly higher than the airflow circulating in the internal cooling air duct of the motor.

[0010] S2. The high-speed airflow of the electric oil mist fan extracts the oil mist gas-liquid from the labyrinth oil seal between the circular skeleton oil seal and the main shaft.

[0011] S3. The oily mist is filtered and separated by the oil-gas separator. The oil flows into the oil storage cup and the gas is discharged through the gas pipeline.

[0012] S4. Periodically return the oil collected in the oil storage cup to the oil drum manually.

[0013] Furthermore, the electric oil mist fan is equipped with manual start / stop control and automatic interlock control for start / stop.

[0014] Furthermore, the automatic interlock control for start and stop adopts an interlock between the electric oil mist fan and the oil pump operation signal, and the electric oil mist fan is automatically started after the oil pump is turned on.

[0015] Furthermore, the electric oil mist fan is equipped with overload alarm, open circuit alarm, fault short circuit grounding, and trip protection.

[0016] The beneficial effects of this invention are:

[0017] This system uses an electric oil mist extraction fan to create a convection channel between the air duct and the balanced airflow cavity of the motor bearing, reducing the flow of oil mist into the motor through the cavity air gap and effectively preventing oil mist from adhering to the coil surface; it also prevents oil mist and dust in the air from corroding the coil insulation and affecting the main insulation of the motor coil. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the system structure of the present invention;

[0019] In the diagram: 1. Control power supply box; 2. Electric oil mist fan; 3. Oil-gas separator; 4. Oil reservoir; 5. Motor drive side; 6. Motor free side; 7-1. Manual valve for regulating air pressure during air venting; 7-2. Manual valve for regulating positive pressure on the drive side; 7-3. Manual valve for regulating positive pressure on the free side; 7-4. Manual valve for regulating negative pressure on the drive side; 7-5. Manual valve for regulating negative pressure on the free side; 7-6. Manual valve for regulating total negative pressure; 8. Semi-circular ring-shaped oil seal; 9. Motor spindle; 10. Coaxial annular air duct balance chamber for motor bearing balance; 11. Plan view of circulating airflow in the internal cooling duct of the motor. Detailed Implementation

[0020] The invention will be further described below with reference to the accompanying drawings:

[0021] A negative pressure system for eliminating oil leakage from the bearings of high-power electric motors, such as Figure 1 As shown, it includes: a control AOC power supply box 1, an electric oil mist fan 2, an oil-gas separator 3, an oil reservoir 4, air ducts and manual valves. The control power supply box 1 is interlocked with the operating signals of the electric oil mist fan 2 and the main process system motor oil pump. The air outlet of the electric oil mist fan 2 is connected to the motor drive side balance air duct inlet 5-1 of the motor drive side 5 and the motor free side balance air duct inlet 6-1 of the motor free side 6 through air ducts. The motor drive side balance air duct outlet 5-2 of the motor drive side 5 and the motor free side balance air duct outlet 6-2 of the motor free side 6 are connected to the oil-gas separator 3 through air ducts. The oil circuit of the oil-gas separator 3 is connected to the oil reservoir 4, and the air circuit of the oil-gas separator 3 is connected to the air inlet of the electric oil mist fan 2.

[0022] The manual valves include: an air exhaust regulating manual valve 7-1 installed in the air outlet duct of the electric oil mist fan 2; a drive-side positive pressure regulating manual valve 7-2 installed in the air inlet 5-1 of the motor drive-side balance air duct; a free-side positive pressure regulating manual valve 7-3 installed in the air inlet 6-1 of the motor free-side balance air duct; a drive-side negative pressure regulating manual valve 7-4 installed in the air outlet 5-2 of the motor drive-side balance air duct; a free-side negative pressure regulating manual valve 7-5 installed in the air outlet 6-2 of the motor free-side balance air duct; and a negative pressure overall regulating manual valve 7-6 installed in the air inlet of the oil-gas separator 3.

[0023] Among them, the air inlet 5-1 of the motor-driven side balance air duct, the air inlet 6-1 of the motor-free side balance air duct, the air outlet 5-2 of the motor-driven side balance air duct, and the air outlet 6-2 of the motor-free side balance air duct are respectively connected to the air duct pipeline using spring tube PVC pipe.

[0024] A method for using a negative pressure system to eliminate oil leakage from the bearings of high-power electric motors includes:

[0025] S1. Using an electric oil mist fan 2, the airflow of the air duct pipeline and the airflow of the balance airflow cavity of the motor drive side bearing 5 and the motor free side bearing 6 are formed into a convection channel, and the airflow pressure in the coaxial annular air duct balance cavity 10 of the motor bearing balance air duct is equalized to the circulating airflow 11 that is slightly higher than the internal cooling air duct of the motor.

[0026] S2. The high-speed airflow of the electric oil mist fan 2 extracts the oil mist gas-liquid from the labyrinth oil seal between the circular skeleton oil seal 8 and the main shaft 9.

[0027] S3. The oily mist is filtered and separated by the oil-gas separator 3. The oil flows into the oil storage cup 4, and the gas is discharged through the gas pipeline.

[0028] S4. Periodically, manually return the oil collected in oil cup 4 to the oil drum;

[0029] The start / stop of the electric oil mist fan 2 is set to manual control and automatic interlock control. The automatic interlock control is based on the interlock between the electric oil mist fan 2 and the operating signal of the main process system motor oil pump. After the main process system motor oil pump is turned on, the electric oil mist fan 2 is automatically started. The electric oil mist fan 2 is equipped with overload alarm, open circuit alarm, fault short circuit grounding, and trip protection functions.

Claims

1. A method for using a negative pressure system to eliminate oil leakage from the bearings of high-power electric motors, characterized in that: The negative pressure system includes a control power supply box, an electric oil mist fan, an oil-gas separator, an oil reservoir, air ducts, and a manual valve. The control power supply box is interlocked with the operating signals of the electric oil mist fan and the main process system's motor oil pump. The outlet of the electric oil mist fan is connected via air ducts to both the motor drive-side balance air duct inlet and the motor free-side balance air duct inlet. The motor drive-side balance air duct outlet and the motor free-side balance air duct outlet are connected via air ducts to the oil-gas separator. The oil circuit of the oil-gas separator is connected to the oil reservoir, and the air circuit of the oil-gas separator is connected to the inlet of the electric oil mist fan. The manual valve includes an air exhaust valve located in the air duct of the electric oil mist fan outlet. The system includes a manual valve for adjusting air pressure, a manual valve for adjusting positive pressure on the drive side of the balanced air duct inlet, a manual valve for adjusting positive pressure on the free side of the balanced air duct inlet, a manual valve for adjusting negative pressure on the drive side of the balanced air duct outlet, a manual valve for adjusting negative pressure on the free side of the balanced air duct outlet, and a manual valve for adjusting total negative pressure at the inlet of the oil-gas separator. The balanced air duct inlet, the balanced air duct inlet, the balanced air duct outlet, and the balanced air duct outlet on the drive side of the motor are connected to the air ducts using spring-loaded PVC pipes. The usage of a negative pressure system includes: S1. An electric oil mist fan is used to form a convection channel between the air duct and the balanced airflow chamber of the motor bearing, so as to equalize the airflow pressure in the motor bearing breathing equalization chamber to the airflow that is slightly higher than the airflow circulating in the internal cooling air duct of the motor; the start and stop of the electric oil mist fan is set to manual control start and stop and automatic interlock control start and stop. The automatic interlock control start and stop adopts the electric oil mist fan and the oil pump operation signal interlock, and the electric oil mist fan is automatically started after the oil pump is turned on. S2. The high-speed airflow of the electric oil mist fan extracts the oil mist gas-liquid from the labyrinth oil seal between the circular skeleton oil seal and the main shaft. S3. The oily mist is filtered and separated by the oil-gas separator. The oil flows into the oil storage cup and the gas is discharged through the gas pipeline. S4. Periodically return the oil collected in the oil storage cup to the oil drum manually.

2. The method of using the negative pressure system for eliminating oil leakage from the bearings of high-power motors according to claim 1, characterized in that: The electric oil mist fan is equipped with control box protection against underpressure, overload, open circuit, and fault short circuit grounding; it is interlocked with the main process oil station circulating pump to achieve green energy saving.

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