Direct air cooling structure of three-phase asynchronous variable frequency motor for electric fracturing

Abstract

The present invention discloses a direct air cooling structure of a three-phase asynchronous variable frequency motor for electric fracturing, which solves the problem of how to achieve a high protection level for a three-phase asynchronous variable frequency motor for electric fracturing with high power density on site. A cooling air inlet and a cooling air outlet are respectively arranged on the motor, and an external closed cooling air inlet duct is connected to the cooling air inlet, and an isolation plate is arranged in the cooling air inlet duct to divide the duct into an isolation area and an air inlet area, so that the leaked rainwater entering the cooling air inlet duct is isolated in the isolation area and cannot enter the motor, and an air inlet is arranged on the side vertical plate of the cooling air inlet duct, and a shutter and a filter are respectively arranged on the air inlet to achieve the blocking of rainwater and dust; a closed air outlet is arranged on the cooling air outlet, and a centrifugal fan blade closed wind cover is connected to the air outlet, and shutters are respectively arranged on the front and rear vertical plates of the centrifugal fan blade closed wind cover to block rainwater from entering the exhaust fan blade closed wind cover.

Description

Technical Field

[0001] The invention relates to a direct air cooling structure of a motor, and in particular to a direct air cooling structure of a three-phase asynchronous variable frequency motor for electric drive fracturing. Background Art

[0002] In natural gas extraction, the driving mode of fracturing pumps has been gradually replaced by direct drive of variable frequency motors instead of the original diesel engine. The three-phase asynchronous variable frequency motor is integrated into the fracturing vehicle or fracturing skid. The system has strict restrictions on the weight, size and protection level of the three-phase asynchronous variable frequency motor. The power density of the integrated three-phase asynchronous variable frequency motor is very high, and it has high requirements for the ventilation and cooling of the motor. The motor protection level reaches IP44, which means that dust and moisture with a diameter of 1 mm are not allowed to enter the motor. Conventional motors with high protection levels generally use air-to-air cooling or air-to-water cooling. The air-to-air cooling method has the characteristics of limited heat exchange effect and is not suitable for high The high-power-density fracturing pump drive motor adopts an air-water cooling cooling method, which requires a larger water-cooled heat exchanger installation space on the outside of the motor, while the motor integrated on the fracturing vehicle or fracturing skid cannot provide space for installing a water-cooled heat exchanger; the fracturing pump drive motor can only adopt a direct air-cooling cooling method, and the traditional motor direct air-cooling cooling structure, that is, a fan is set at the motor end cover, has a protection level that cannot meet the IP44 protection level requirement for the three-phase asynchronous variable-frequency motor for electric fracturing; how to simultaneously meet the cooling requirements and high protection level requirements of the high-power-density three-phase asynchronous variable-frequency motor has become a difficult problem that needs to be solved for the on-site three-phase asynchronous variable-frequency motor for electric fracturing. Summary of the invention

[0003] The present invention provides a direct air cooling structure for a three-phase asynchronous variable frequency motor for electric fracturing, which solves the technical problem of how to achieve a high protection level for a three-phase asynchronous variable frequency motor for electric fracturing with high power density on site.

[0004] The present invention solves the above technical problems through the following technical solutions:

[0005] The overall concept of the present invention is as follows: a cooling air inlet is provided at the driving end of the three-phase asynchronous variable frequency motor for electric fracturing, a cooling air outlet is provided at the non-driving end of the three-phase asynchronous variable frequency motor for electric fracturing, an external closed cooling air inlet duct is connected to the cooling air inlet, an isolation plate is provided in the cooling air inlet duct, the duct is divided into an isolation area and an air inlet area, so that leaked rainwater entering the cooling air inlet duct is isolated in the isolation area and cannot enter the motor, an air inlet is provided on the side vertical plate of the cooling air inlet duct, and a shutter and a filter are respectively provided on the air inlet to achieve rain control. Water and dust are blocked; a closed air outlet is arranged on the cooling air outlet, a centrifugal fan blade closed wind hood is connected to the air outlet, shutters are respectively arranged on the front and rear vertical plates of the centrifugal fan blade closed wind hood to block rainwater from entering the exhaust fan blade closed wind hood, the centrifugal fan blade closed wind hood and the air outlet are separately arranged and connected by a horn induced draft tube to ensure to the greatest extent that rainwater and dust in the environment cannot enter the motor through the air outlet; the cooling air inlet air path and the exhaust air path after the cooling motor are arranged in a cross shape to prevent the two winds from interfering with each other, thereby ensuring the air intake quality of the cooling air.

[0006] A direct air cooling structure of a three-phase asynchronous variable frequency motor for electric fracturing, comprising a three-phase asynchronous variable frequency motor and a centrifugal fan drive motor, wherein a motor drive end air inlet and a motor non-drive end air outlet are respectively arranged at the top of a base of the three-phase asynchronous variable frequency motor; a closed air inlet cylinder is connected to the motor drive end air inlet, an air inlet window is arranged on the left side elevation of the closed air inlet cylinder, an L-shaped isolation plate is arranged in the closed air inlet cylinder inside the air inlet window, the L-shaped isolation plate divides the inner cavity of the closed air inlet cylinder into an upward air induction area and a downward air induction area, and a filter screen and an air inlet shutter are respectively arranged on the air inlet window; a closed air outlet is connected to the non-drive end air outlet of the motor A tube, a bell-shaped induced draft tube is connected to the left side facade of the closed air outlet tube, a closed centrifugal fan impeller cover is connected to the outlet of the bell-shaped induced draft tube, the centrifugal fan impeller is arranged in the closed centrifugal fan impeller cover, the output shaft of the centrifugal fan drive motor arranged at the top of the three-phase asynchronous frequency conversion motor base is extended into the centrifugal fan impeller cover and then connected with the centrifugal fan impeller, a front side air outlet window is arranged on the front side facade of the centrifugal fan impeller cover, a front side louver is arranged on the front side air outlet window, a rear side air outlet window is arranged on the rear side facade of the centrifugal fan impeller cover, and a rear side louver is arranged on the rear side air outlet window.

[0007] A V-shaped water storage area is arranged at the lower part between the air inlet louver and the L-shaped isolation plate, a V-shaped water storage area drain outlet is arranged at the bottom end of the V-shaped water storage area, and an impeller cover drain outlet is arranged at the lower end of the centrifugal fan impeller cover; the louvers on the air inlet louver, the louvers on the front louvers and the louvers on the rear louvers are all louvers that are 60 degrees to the up and down vertical direction; the filter net is a stainless steel wire woven net that prevents 1 mm solid particles from passing through.

[0008] The invention meets the requirements of high-level protection IP44, has a simple structure, good cooling effect, the cooling hood provides forced ventilation cooling for the motor, is easy to disassemble, maintain and clean, and fully meets the outdoor working environment of the fracturing pump group. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is a schematic diagram of the structure of the present invention;

[0010] Figure 2 It is a schematic diagram of the structure of the present invention in the left viewing direction. DETAILED DESCRIPTION

[0011] The present invention is described in detail below in conjunction with the accompanying drawings:

[0012] A direct air cooling structure of a three-phase asynchronous variable frequency motor for electric fracturing, comprising a three-phase asynchronous variable frequency motor and a centrifugal fan drive motor 16, wherein a motor drive end air inlet 2 and a motor non-drive end air outlet 3 are respectively arranged at the top of a three-phase asynchronous variable frequency motor base 1; a closed air inlet 4 is connected to the motor drive end air inlet 2, an air inlet window 5 is arranged on the left side elevation of the closed air inlet 4, an L-shaped isolation plate 6 is arranged in the closed air inlet 4 inside the air inlet window 5, the L-shaped isolation plate 6 divides the inner cavity of the closed air inlet 4 into an upward air induction area 7 and a downward air induction area 8, and a filter screen 10 and an air inlet shutter 11 are respectively arranged on the air inlet window 5; a closed air outlet 12 is connected to the motor non-drive end air outlet 3, and a closed air outlet 12 is connected to the motor non-drive end air outlet 3. A bell-mouth induced draft tube 13 is connected to the left side facade of the closed air outlet duct 12, and a closed centrifugal fan impeller cover 14 is connected to the outlet of the bell-mouth induced draft tube 13. A centrifugal fan impeller 15 is arranged in the closed centrifugal fan impeller cover 14, and an output shaft of a centrifugal fan drive motor 16 arranged at the top of the three-phase asynchronous frequency conversion motor base 1 is extended into the centrifugal fan impeller cover 14 and connected to the centrifugal fan impeller 15. A front side air outlet window 17 is arranged on the front side facade of the centrifugal fan impeller cover 14, and a front side shutter 18 is arranged on the front side air outlet window 17. A rear side air outlet window is arranged on the rear side facade of the centrifugal fan impeller cover 14, and a rear side shutter is arranged on the rear side air outlet window.

[0013] A V-shaped water storage area 9 is arranged at the lower part between the air inlet louver 11 and the L-shaped isolation plate 6, a V-shaped water storage area drain outlet 19 is arranged at the bottom end of the V-shaped water storage area 9, and an impeller cover drain outlet 20 is arranged at the lower end of the centrifugal fan impeller cover 14; the louvers on the air inlet louver 11, the louvers on the front side louvers 18 and the louvers on the rear side louvers are all louvers that are 60 degrees to the upper and lower vertical directions; the filter screen 10 is a stainless steel wire woven screen that prevents 1 mm solid particles from passing through.

[0014] After the centrifugal fan driving motor 16 is started, the centrifugal fan impeller 15 rotates, and the hot air in the cooling motor first enters the closed air outlet 12 vertically through the air outlet 3 at the non-driving end of the motor, and then changes direction through the bell-shaped air induced pipe 13 to enter the centrifugal fan impeller cover 14. Then, driven by the centrifugal fan blades, the hot air is discharged horizontally into the atmosphere through the front air outlet window 17 set on the front side facade of the centrifugal fan impeller cover 14 and the rear air outlet window set on the rear side facade. The blades on the front side louver 18 and the blades on the rear side louver set on the rear side air outlet window are all at an angle of 60 degrees to the vertical direction, forming a shield for rainwater. Rainwater that partially leaks into the centrifugal fan impeller cover 14 will accumulate at the bottom of the centrifugal fan impeller cover 14 and be discharged by the impeller cover drain port 20. The centrifugal fan impeller cover 14 and the closed air outlet 12 are separately isolated, which effectively prevents rainwater from entering the motor from the direct air-cooled air outlet. At the same time, the cooling motor The hot air after the machine is redirected from vertical to horizontal, which also reduces the probability of solid particles larger than 1 mm entering the motor from the air outlet; at the same time, the cold air outside enters the closed air inlet 4 after passing through the filter 10 from the air inlet louver 11, and the cooling air first enters the upward air induction area 7 in the closed air inlet 4. The cooling air moves upward, makes a 180-degree turn at the upper part of the closed air inlet 4, and then enters the downward air induction area 8, moves downward, and enters the motor through the air inlet 2 at the motor drive end. The air inlet louver 11 is The rain outside forms a barrier, and the filter 10 prevents 1 mm solid particles from passing through. Some of the rainwater that leaks into the upward air-inducing area 7 will gather in the V-shaped water storage area 9 and be discharged by the V-shaped water storage area drain outlet 19. The establishment of the L-shaped isolation plate 6 and the upward air-inducing area 7 forms a secondary isolation for rainwater, which avoids rainwater and dust from entering the motor to the greatest extent, achieving a high level of motor protection. The external placement of the centrifugal fan provides powerful cooling air for the motor, while meeting the motor's stringent axial size requirements.

Claims

1. A direct air cooling structure of a three-phase asynchronous variable frequency motor for electric fracturing, comprising a three-phase asynchronous variable frequency motor and a centrifugal fan drive motor (16), characterized in that: The motor drive end air inlet (2) and the motor non-drive end air outlet (3) are respectively arranged at the top of the three-phase asynchronous variable frequency motor base (1); the motor drive end air inlet (2) is connected to a closed air inlet duct (4); an air inlet window (5) is arranged on the left side elevation of the closed air inlet duct (4); an L-shaped isolation plate (6) is arranged in the closed air inlet duct (4) inside the air inlet window (5); the L-shaped isolation plate (6) divides the inner cavity of the closed air inlet duct (4) into an upward air induction area (7) and a downward air induction area (8); a filter screen (10) and an air inlet louver (11) are respectively arranged on the air inlet window (5); the motor non-drive end air outlet (3) is connected to a closed air outlet duct (12); a closed air outlet duct (12) is connected on the left side elevation of the closed air outlet duct (12); A bell-mouth induced draft duct (13) is connected to an outlet of the bell-mouth induced draft duct (13). A centrifugal fan impeller cover (14) is arranged in the sealed centrifugal fan impeller cover (14). An output shaft of a centrifugal fan drive motor (16) arranged at the top of a three-phase asynchronous variable frequency motor base (1) extends into the centrifugal fan impeller cover (14) and is connected to the centrifugal fan impeller (15). A front air outlet window (17) is arranged on the front side elevation of the centrifugal fan impeller cover (14), and a front louver (18) is arranged on the front air outlet window (17). A rear air outlet window is arranged on the rear side elevation of the centrifugal fan impeller cover (14), and a rear louver is arranged on the rear air outlet window.

2. The direct air cooling structure of a three-phase asynchronous variable frequency motor for electric fracturing according to claim 1 is characterized in that: A V-shaped water storage area (9) is provided at the lower part between the air inlet louver (11) and the L-shaped isolation plate (6), a V-shaped water storage area drain outlet (19) is provided at the bottom end of the V-shaped water storage area (9), and an impeller cover drain outlet (20) is provided at the lower end of the centrifugal fan impeller cover (14); the louvers on the air inlet louver (11), the louvers on the front side louver (18) and the louvers on the rear side louver are all louvers that are 60 degrees to the vertical direction; the filter screen (10) is a stainless steel wire woven screen that prevents 1 mm solid particles from passing through.

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