Noise reduction device for large fan body and motor in power plant

Abstract

The invention discloses a noise reduction device for a large fan body and a motor in a power plant, which comprises a sound absorption and insulation cover body in which the fan and the motor are arranged, and a maintenance gap is reserved between the sound absorption and insulation cover body and the motor or the fan; a cold air inlet is formed in the lower portion of the side wall, away from the air inlet end of the motor cooling fan, of the sound absorption and insulation cover body and is close to the cover wall of the output shaft side of the motor, and a cold air inlet silencer is installed on the cold air inlet. The wind scooper covering the motor in size is arranged above the motor, one end of the wind scooper is provided with the wind guide pipe, the wind guide pipe is communicated with the air inlet pipe of the fan, external cold air is pulled into the sound absorption and insulation cover body from the cold air inlet silencer by means of the power of the motor cooling fan, and the motor is cooled by moving from the motor output shaft end to the motor cooling fan end. And meanwhile, the negative pressure of the fan is utilized to introduce heat into the air inlet pipe from the air guide pipe to realize heat dissipation. According to the motor sound absorption and insulation cover, the contradiction between heat dissipation and noise reduction of the motor is solved; the air inlet and outlet design solves the problems of air noise and working noise of the fan.

Description

Technical Field

[0001] The invention relates to a noise reduction device for a large-scale fan body and a motor in a power plant, belonging to the technical field of noise control equipment. Background Art

[0002] The large fans used in power plant equipment are mainly primary fans and blowers. The primary fans are mainly used to dry and transport pulverized coal into the furnace, and the blowers are mainly used to supply air to the combustion furnace to maintain the combustion process in the furnace. A primary fan is generally composed of a motor, a reducer, a rotor, a cabinet, a base, an impeller, a guide vane and an inlet pipe. A blower is generally composed of a motor, a reducer, a gear, an impeller, a frame, a volute, an air inlet and an outlet. In a thermal power plant, each fan has its specific application. Since the motor noise of the primary fan and the blower is loud, it seriously affects the health of production personnel or surrounding residents, so noise reduction treatment is required. In order to solve this problem, corresponding technical solutions are needed. We searched the existing technology and obtained corresponding search results. Specific examples are as follows: For example, CN202321674490.4 discloses a slag bin dust removal system for a circulating fluidized bed boiler in a thermal power plant, wherein a primary air mechanism is disclosed, including a plurality of air supply fans (4), the inlets of the air supply fans (4) are connected to a plurality of air inlet pipes (5), and the inlets of the air inlet pipes (5) are connected to a muffler (18). Another example is a lubricating oil fume treatment device for a power plant disclosed in CN202123076238., including an exhaust pipe connected to an oil tank, the other end of which is divided into an exhaust pipe branch and an exhaust pipe main line, the other end of the exhaust pipe main line is connected in parallel with a muffler and a blower, and the outlet of the blower is connected to an air preheater through a pipeline. We also found patents such as CN202122696487.X, which discloses a thermal power plant blower with a vibration-damping and noise-reducing structure. The patent includes a vibration-damping assembly at the top of the base, a movable plate at the top of which the blower is mounted via fasteners. Sliding assemblies are provided at the left and right ends of the vibration-damping assembly, and a soundproofing plate is provided at one end of the sliding assembly. The soundproofing plate is higher than the blower. This patent addresses the problem of noise caused by the violent vibrations of the blower during use, which can harm workers.

[0003] The above search reveals that fans typically employ mufflers at the air inlet or further noise reduction through vibration damping. These methods do not address the noise of the motors that drive the fans. While installing mufflers at the air inlet or inlet duct can reduce some noise, this solution has limitations, such as inherent motor and fan noise.

[0004] Further research and analysis revealed a detachable dual-circuit ventilation and heat dissipation soundproof enclosure, such as the one disclosed in CN201620476673.9. The enclosure comprises an enclosure 1, with an air inlet 2 at one end and motor cooling vents 3 and exhaust cooling vents 4 at the top. Fans are installed in each of the air inlet, motor cooling vents, and exhaust cooling vents. The air inlet is equipped with an air inlet muffler 5, the motor cooling vent is equipped with a fan muffler 6, and the exhaust cooling vent is equipped with an exhaust muffler 7. A soundproof door 8 is installed on one side of the enclosure. A temperature sensor 9 is installed at the top of the enclosure, connected to the fans at the motor cooling vents 3 and exhaust cooling vents 4 via a temperature-controlled switch 10. The outer surface of the enclosure is equipped with embedded connectors 11 for connecting to other enclosures. Hot air is drawn in through the air inlet 2, dissipated through the dual circuits, and then discharged through the motor cooling vents 3 and exhaust cooling vents 4.

[0005] To reduce noise, a soundproof enclosure is used. To dissipate heat, air inlets, motor cooling vents, and exhaust cooling vents are designed. Fans are installed inside, and temperature control components are also designed. The structure is complex, and the manufacturing and use costs are high. The use of power cooling also consumes more energy.

[0006] Our company also adopted a similar structure in its early designs, such as the large motor silencer chamber structure in CN201410469072.0. A sound-absorbing and sound-insulating wall 9 surrounds the large motor. The motor's cooling fan 4 is introduced into a ventilation muffler 6 via a duct 5, ensuring that the air entering the motor is cool air from the outside, facilitating heat dissipation. The cooling fan 4's outlet is connected to the outside via an air duct 3, with a ventilation muffler 8 installed at the outlet. The remaining heat from the motor is dissipated through the ventilation mufflers 6 on the three side walls 9 and the forced ventilation muffler 7 on the top wall. The muffler volume of 6, 7, and 8 is comparable to that of the chamber's sound-absorbing and sound-insulating walls. Sound-insulated observation windows (i.e., skylights) 11 are installed on the side walls 9, along with a sound-absorbing and sound-insulating inspection door 10 for easy access. The sound-absorbing and sound-insulating top wall 12 can be lifted (or removed) when the motor needs to be removed for overhaul.

[0007] The aforementioned technical solutions, through soundproof enclosures or sound-absorbing enclosures, have achieved some success in reducing noise. However, their complex structures, long on-site installation cycles, high manufacturing and operating costs, numerous failure points, and high energy consumption have fallen short of the company's requirements. Furthermore, no solution has been found for simultaneously reducing the noise of large fans and fan motors, and reducing maintenance time. Summary of the Invention

[0008] Based on the technical requirements of power plant customers and in view of the above-mentioned problems in existing technologies, our company organized R&D personnel to tackle the problems and finally came up with a motor noise reduction device for power plant primary fans or blowers. This device not only solves the problem of noise leakage from motors and fans, but also meets the requirements of motor ventilation and heat dissipation without the need for external power, thus saving energy and reducing maintenance.

[0009] The technical solution provided by the present invention is as follows: a noise reduction device for a large fan body and a motor in a power plant, comprising a sound-absorbing and insulating cover in which the fan and the motor are placed, with a maintenance gap left between the sound-absorbing and insulating cover and the motor or the fan; a cool air inlet is provided on the lower part of the side wall of the sound-absorbing and insulating cover away from the air inlet end of the motor heat dissipation fan and on the cover wall close to the motor output shaft side, and a cool air inlet silencer is installed on the cool air inlet; an air guide cover of a size covering the motor is provided above the motor, an air guide duct is installed at one end of the air guide cover, and the air guide duct is connected to the air inlet duct of the fan, and external cool air is drawn into the sound-absorbing and insulating cover through the cool air inlet silencer by relying on the power of the motor heat dissipation fan, and moves along the motor output shaft end to the motor heat dissipation fan end to dissipate heat from the motor, and at the same time, the negative pressure of the fan is utilized to introduce heat from the air guide cover and the air guide duct into the air inlet duct to achieve heat dissipation.

[0010] Furthermore, the motor is installed on a motor mounting base above the ground through a motor fixing bracket, a ventilation gap is left between the motor and the mounting base, and the motor fixing bracket is fixed by a fixing rod embedded in the mounting base; the fan is installed on a fan mounting base above the ground and adjacent to the motor mounting base through a fan fixing bracket, and the fan fixing bracket is fixed by a fixing rod embedded in the mounting base.

[0011] Furthermore, the installation position of the cool air inlet silencer corresponds to the ventilation gap.

[0012] Furthermore, two cool air inlets are provided and are symmetrical with the motor.

[0013] Furthermore, an air volume control valve is provided on the air duct, and the air volume flowing from the air duct into the air induction duct is controlled by controlling the switch and opening and closing amount of the air volume control valve.

[0014] Furthermore, the air inlet of the fan is connected to one end of the air inlet connecting pipe, and the other end of the air inlet connecting pipe is connected to the induced air duct. The induced air duct includes an elbow pipe that changes the direction from horizontal to vertical, and an air inlet pipe connected to the elbow pipe. An air inlet muffler is provided on the air inlet pipe. The air outlet of the fan is connected to the small end of the flared pipe through the air outlet connecting pipe, and the large end of the flared pipe is connected to the air outlet muffler. The elbow pipe, air inlet connecting pipe, air outlet connecting pipe and flared pipe are all located inside the sound absorbing and insulating cover.

[0015] Furthermore, a plurality of fan side cooling air openings are provided on the lower part of the sound-absorbing and isolating cover and on the cover wall located at the expanded pipe, and fan side ventilation silencers are provided on the fan side cooling air openings.

[0016] Furthermore, the air outlet silencer is a ventilation silencer with a flow guide structure.

[0017] Furthermore, a plurality of light windows are provided on the upper portion of the cover wall of the sound-absorbing and sound-insulating cover.

[0018] Furthermore, the wall thickness of the sound-absorbing and insulating cover is 6.5 to 15 cm, and the cover is composed of a porous protective plate located inside, a sound insulating plate located outside, a frame connecting the porous protective plate and the sound insulating plate, and sound-absorbing cotton filled in the frame.

[0019] The beneficial effects of the present invention compared to the prior art are: 1. The air guide cover and air duct are designed inside the sound-absorbing and sound-insulating enclosure, and cooperate with the motor's own cooling fan and the cool air inlet silencer set on the enclosure wall near the motor output shaft to form a circulation channel for cool air to enter, dissipate heat for the entire motor, and then lead out hot air. No external power is required. The structural design is ingenious, and the sound-absorbing and sound-insulating enclosure is used for noise control, ultimately resolving the contradiction between motor heat dissipation and motor and fan noise reduction. 2. Change the air inlet side from large to small and the air outlet side from small to large to change the wind speed to reduce noise. Use an air inlet silencer and a pipe wall-covered sound-absorbing insulation layer to solve the air duct noise. Place the fan and the air outlet expansion pipe in a fan sound-absorbing soundproof cover to eliminate noise. Assist the fan side ventilation silencer to adjust the ventilation and temperature inside the sound-absorbing soundproof cover, thereby solving the wind noise and fan working noise. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic structural diagram of Example 1 of the present invention; Figure 2 Schematic diagram of wind flow in Example 1 of the present invention; In the figure: 1. Motor, 2. Sound-absorbing and sound-insulating cover, 3. Cool air inlet silencer, 4. Fan, 5. Motor cooling fan, 6. Air guide cover, 7. Air guide duct, 8. Elbow pipe, 9. Skylight, 10. Air volume control valve, 11. Air inlet duct, 12. Flaring pipe, 13. Air outlet silencer, 14. Air inlet silencer, 15. Fan side ventilation silencer. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Example

[0022] like Figure 1 、 2 The noise reduction device for a large fan body and motor in a power plant shown in the figure comprises a sound-absorbing and insulating cover 2 in which a fan 4 and a motor 1 are placed, and a maintenance gap is left between the sound-absorbing and insulating cover 2 and the motor 1 or the fan 4; a cool air inlet is provided on the lower part of the side wall of the sound-absorbing and insulating cover 2 away from the air inlet end of the motor heat dissipation fan 5 and on the cover wall near the motor output shaft side, and a cool air inlet silencer 3 is installed on the cool air inlet. Two cool air inlets are provided and are symmetrical with the motor 1, and air enters the motor 1 on both sides, as shown in FIG. Figure 2 The middle arrow points to a better solution to the problem of motor ventilation and heat dissipation.

[0023] An air duct 6 of a size that covers the motor is provided above the motor 1. An air duct 7 is installed at one end of the air duct 6. The air duct 7 is connected to the air inlet duct of the fan 4. The power of the motor cooling fan 5 is used to draw external cool air from the cool air inlet muffler 3 into the sound-absorbing and insulating cover 2, and moves along the motor output shaft end to the motor cooling fan end to dissipate heat from the motor 1. At the same time, the negative pressure of the fan 4 is used to introduce heat from the air duct 6 and the air duct 7 into the air inlet duct to achieve heat dissipation. An air volume control valve 10 is provided on the air duct 7. By controlling the opening and closing amount of the air volume control valve 10, the air volume flowing from the air duct into the air inlet duct is controlled. The heat dissipation simultaneously utilizes the power generated by the cooling fan of the motor and the negative pressure generated by the operation of the fan.

[0024] Motor 1 is mounted on a motor mounting base elevated above the ground via a motor mounting bracket, with a ventilation gap between motor 1 and the mounting base. The motor mounting bracket is secured via a fixing rod embedded in the mounting base, and the installation position of the cool air inlet muffler 3 corresponds to the ventilation gap. A cool air inlet is provided at the lower portion of the sidewalls of the sound-absorbing and insulating enclosure 2 on both sides of motor 1, symmetrically arranged around motor 1. The installation position of the cool air inlet muffler 3 corresponds to the ventilation gap. This allows air to enter from both sides of motor 1 and effectively guides the airflow, better solving the problem of overall ventilation and heat dissipation of the motor.

[0025] Fan 4 is mounted on a fan mounting base, elevated above the ground and adjacent to the motor mounting base, using a fan mounting bracket. The fan mounting bracket is secured by fixing rods embedded in the mounting base. The structure of the motor mounting bracket, fixing rods, and mounting base further optimizes the ventilation and heat dissipation of the motor and eliminates the problem of structure-borne noise caused by vibration during operation of the motor and fan.

[0026] The sound-absorbing and insulating enclosure 2 has three to five skylights 9 located on its upper wall. These windows provide a clear view of the interior during maintenance. The enclosure 2 has an 8.5 cm thick wall and consists of an internal porous protective plate, an external soundproofing plate, a frame connecting the two plates, and sound-absorbing cotton filling the frame. The wall thickness is designed based on measured noise levels to ensure that noise control meets standards. Example

[0027] As a further design of Example 1, the air inlet of the fan 4 is connected to one end of the air inlet connecting pipe, the other end of which is connected to the induced draft pipe. The induced draft pipe includes an elbow pipe 8 that changes its direction from horizontal to vertical, and an air inlet pipe 11 connected to the elbow pipe 8. An air inlet muffler 14 is provided on the air inlet pipe 11. The air outlet of the fan is connected to the small end of the expanded pipe 12 through the air outlet connecting pipe, and the large end of the expanded pipe 12 is connected to the air outlet muffler 13. The elbow pipe 8, the air inlet connecting pipe, the air outlet connecting pipe, and the expanded pipe 12 are all located within the sound-absorbing and insulating enclosure 2. An integral sound-absorbing and insulating enclosure is used to control noise from the fan and motor, and a special structural design is applied to the fan noise to ensure wind noise control.

[0028] Two fan-side cooling air openings are provided on the lower portion of the sound-absorbing and insulating enclosure 2, located on the enclosure wall at the flared tube 12. Fan-side ventilation silencers 15 are installed in these openings. These openings further introduce cool air, bringing the temperature inside the enclosure closer to the outdoor temperature, making it easier for personnel to enter for maintenance and ensuring effective heat dissipation for the motor.

[0029] The air outlet silencer 13 is a ventilation silencer with a flow guide structure. The flow guide structure is designed after the expansion structure of the expansion pipe, which can further reduce wind noise and achieve fan noise reduction.

[0030] The air inlet pipe 11 is composed of an air inlet constriction pipe, a top pipe and a pipe cap. The large-diameter end of the air inlet constriction pipe is connected to one end of the air inlet silencer 14, and the other end of the air inlet silencer 14 is connected to the top pipe. A pipe cap is set on the top of the top pipe, and an air inlet is set between the top pipe and the pipe cap. The small-diameter end of the air inlet constriction pipe is connected to the elbow pipe 8. The outer surface of the air inlet constriction pipe is covered with a sound-absorbing and insulating layer. The air inlet side is changed from large to small and the air outlet side is changed from small to large to change the wind speed to reduce noise. The air inlet silencer is added to the pipe wall to cover the sound-absorbing and insulating layer to solve the air duct noise. The fan and the air outlet expansion pipe are placed in a fan sound-absorbing and insulating cover to eliminate noise. The fan side ventilation silencer is used to assist in ventilation and temperature adjustment inside the sound-absorbing and insulating cover, thereby solving wind noise and fan operating noise.

[0031] The above embodiments are merely explanations and illustrations of the technical solution of the present invention and are not intended to limit the scope of protection of the technical solution of the present invention. All simple variations based on this solution fall within the scope of protection of the present invention.

Claims

1. A noise reduction device for a large fan body and motor in a power plant, characterized by: The utility model comprises a sound-absorbing and insulating cover body in which a fan and a motor are placed, and a maintenance gap is left between the sound-absorbing and insulating cover body and the motor or the fan; a cool air inlet is arranged on the lower part of the side wall of the sound-absorbing and insulating cover body away from the air inlet end of the motor heat dissipation fan and on the cover wall close to the motor output shaft side, and a cool air inlet muffler is installed on the cool air inlet; an air guide cover of a size covering the motor is arranged above the motor, an air guide pipe is installed at one end of the air guide cover, and the air guide pipe is connected to the air inlet pipe of the fan, and the external cool air is drawn into the sound-absorbing and insulating cover body through the cool air inlet muffler by relying on the power of the motor heat dissipation fan, and moves along the motor output shaft end to the motor heat dissipation fan end to dissipate the heat of the motor, and at the same time, the negative pressure of the fan is used to introduce the heat from the air guide cover and the air guide pipe into the air inlet pipe to achieve heat dissipation.

2. The noise reduction device for a large-scale fan body and motor in a power plant according to claim 1 is characterized in that: The motor is installed on a motor mounting foundation above the ground through a motor fixing frame, a ventilation gap is left between the motor and the mounting foundation, and the motor fixing frame is fixed by a fixing rod embedded in the mounting foundation; the fan is installed on a fan mounting foundation above the ground and adjacent to the motor mounting foundation through a fan fixing frame, and the fan fixing frame is fixed by a fixing rod embedded in the mounting foundation.

3. The noise reduction device for a large-scale fan body and motor in a power plant according to claim 2 is characterized in that: The installation position of the cool air inlet silencer corresponds to the ventilation gap.

4. The noise reduction device for a large-scale fan body and motor in a power plant according to claim 1 is characterized in that: The two cool air inlets are arranged symmetrically with respect to the motor.

5. The noise reduction device for a large-scale fan body and motor in a power plant according to claim 1 is characterized in that: An air volume control valve is provided on the air duct, and the air volume flowing from the air duct into the air induced duct is controlled by controlling the switch and the opening and closing amount of the air volume control valve.

6. The noise reduction device for a large-scale fan body and motor in a power plant according to claim 1 is characterized in that: The fan air inlet is connected to one end of the air inlet connecting pipe, and the other end of the air inlet connecting pipe is connected to the induced air duct. The induced air duct includes an elbow pipe that changes its direction from horizontal to vertical, and an air inlet pipe connected to the elbow pipe. An air inlet muffler is provided on the air inlet pipe. The fan air outlet is connected to the small end of the flared pipe through the air outlet connecting pipe, and the large end of the flared pipe is connected to the air outlet muffler. The elbow pipe, air inlet connecting pipe, air outlet connecting pipe and flared pipe are all located in the sound absorbing and insulating cover.

7. The noise reduction device for a large-scale fan body and motor in a power plant according to claim 6 is characterized in that: A plurality of fan side cooling air openings are arranged on the lower part of the sound-absorbing and insulating cover body and on the cover wall located at the expanded pipe, and fan side ventilation silencers are arranged on the fan side cooling air openings.

8. The noise reduction device for a large-scale fan body and motor in a power plant according to claim 6 is characterized in that: The air outlet silencer is a ventilation silencer with a flow guide structure.

9. The noise reduction device for a large-scale fan body and motor in a power plant according to claim 1, characterized in that: A plurality of light windows are arranged on the upper part of the cover wall of the sound-absorbing and insulating cover.

10. The noise reduction device for a large-scale fan body and motor in a power plant according to claim 1, characterized in that: The wall thickness of the sound-absorbing and insulating cover is 6.5 to 15 cm, and the cover is composed of a porous protective plate located inside, a sound insulating plate located outside, a frame connecting the porous protective plate and the sound insulating plate, and sound-absorbing cotton filled in the frame.

Images