Flue gas recirculation fan

Abstract

The utility model relates to a flue gas recirculation fan which comprises a motor, a volute front end plate, an impeller, a volute, a rubber ring and an end cover. A first through hole is formed in the horizontal middle of the front end plate of the volute, a second through hole is formed in the horizontal middle of the volute, and the size of the first through hole is smaller than that of the second through hole; a third through hole is formed in the horizontal middle part of the end cover; the inner circumference of the third through hole is matched with the outer circumference of the motor shaft; the motor shaft sequentially penetrates through the front end plate of the volute, the end cover and the impeller to the middle of the volute; the motor shaft is sleeved with the rubber ring, the rubber ring is attached to the end cover of the motor, and the rubber ring is arranged between the end cover of the motor and the front end plate of the volute to seal a gap between the end cover of the motor and the motor shaft. According to the flue gas recirculation fan, the connecting mode is simple, compared with a traditional flue gas recirculation fan, the sealing performance of the connecting position of the motor and the volute is better, water is not prone to being thrown out of the volute and entering the motor along the motor shaft, and burnout or bearing damage caused by water inflow in the running period of the motor is completely eradicated.

Description

Technical Field

[0001] The present application relates to the technical field of flue gas treatment, and in particular to a flue gas recirculation fan. Background Art

[0002] On May 13, 2015, the Beijing Municipal Environmental Protection Bureau and the Beijing Municipal Bureau of Quality and Technical Supervision jointly issued a new Beijing local standard, "Boiler Air Pollutant Emission Standard" DB11 / 139-2015. The new standard will increase the NOx emission of newly built gas boilers from the previous 80mg / m3 to 30mg / m3 from April 1, 2017. At the same time, relevant policies were issued to encourage enterprises to carry out low-nitrogen transformation of existing gas boilers to meet the new emission standards.

[0003] One of the ways to transform gas boilers into low-nitrogen boilers is flue gas recirculation (FGR), which is to send a small amount of low-temperature flue gas at the tail of the gas boiler into the air inlet of the burner through the flue gas recirculation fan to allow it to participate in combustion. The advantages of this solution are low transformation cost and obvious effect. The disadvantages are that the recycled flue gas can easily produce a large amount of condensed water, causing the recirculation fan to burn and a large amount of water to accumulate around the fan. After the water is thrown out of the volute, it enters the motor along the motor shaft, which can cause the front bearing to be scrapped due to emulsification of the lubricating oil, or even burn the motor; another part of the water is thrown around the fan, and the boiler operators often slip and fall during inspections. Therefore, the existing flue gas recirculation fan structure needs to be optimized. Utility Model Content

[0004] In view of this, the present application proposes a flue gas recirculation fan to solve the above problems.

[0005] According to one aspect of the present application, there is provided a flue gas recirculation fan, comprising: a motor, a volute front end plate, an impeller, a volute, a rubber ring and an end cover;

[0006] A first through hole is opened in the horizontal middle of the front end plate of the volute, and a second through hole is opened in the horizontal middle of the volute, and the size of the first through hole is smaller than that of the second through hole;

[0007] The motor has a motor shaft, and a third through hole is opened in the horizontal middle of the end cover; the inner circumference of the third through hole matches the outer circumference of the motor shaft;

[0008] The motor shaft passes through the front end plate of the volute, the end cover, the impeller in sequence to the middle of the volute;

[0009] The rubber ring is sleeved on the motor shaft, and the rubber ring is arranged between the motor end cover and the front end plate of the volute to seal the gap between the motor end cover and the motor shaft.

[0010] In a possible implementation, it further includes: white felt; the white felt ring is arranged circumferentially of the opening of the front end plate of the volute, and the white felt and the rubber ring are arranged on both sides of the opening of the front end plate of the volute opposite to each other.

[0011] In a possible implementation, the end cap is disposed on the rear end surface of the white felt, and the size of the end cap matches the size of the white felt.

[0012] In a possible implementation, the rubber ring is arranged in interference connection with the motor shaft; the rubber ring is a water-retaining rubber ring, and the outer circumference of the rubber ring is larger than the outer circumference of the first through hole.

[0013] In a possible implementation, the end cover is a circular structure, the material of the end cover is nylon, and the outer circumference of the end cover is larger than the outer circumference of the first through hole.

[0014] In a possible implementation, the volute is provided with a drainage hole, the drainage hole is arranged at the bottom of the volute, and the drainage hole is arranged at the outer periphery of the volute.

[0015] In a possible implementation, it also includes: a drain pipe and a water tank; the size of the drain pipe matches the size of the drain hole, one end of the drain pipe is connected to the drain hole, the other end of the drain pipe is connected to the water tank, and the water tank is set in the ditch.

[0016] In a possible implementation, the volute is arranged around the front end plate of the volute, the volute is arranged behind the front end surface of the volute, and the motor is arranged in front of the front end plate of the volute.

[0017] In a possible implementation manner, the first through hole has a circular structure, the second through hole has a circular structure, and the third through hole has a circular structure.

[0018] Beneficial effects of this application:

[0019] The flue gas recirculation fan proposed in this application has a simple structure. The sealing performance of the connection between the motor and the volute in this application is better. Water is not easy to be thrown out from the volute and enter the motor along the motor shaft, which can prevent the motor from being burned or bearing damaged due to water ingress during operation. Specifically, a first through hole is opened in the horizontal middle of the front end plate of the volute, and a second through hole is opened in the horizontal middle of the volute. The size of the first through hole is smaller than that of the second through hole; the motor has a motor shaft, and a third through hole is opened in the horizontal middle of the end cover; the inner circumference of the third through hole fits the outer circumference of the motor shaft; the inner circumference of the rubber ring is interference fit with the outer circumference of the motor shaft, and the outer circumference of the rubber ring is larger than the outer circumference of the first through hole, and the motor shaft passes through the rubber ring to the first through hole; the motor shaft passes through the rubber ring, the front end plate of the volute, the end cover, and the impeller to the middle of the volute in sequence. Compared with the traditional flue gas recirculation fan, the flue gas recirculation fan proposed in this embodiment can also prevent the inspection personnel from slipping and falling and environmental pollution caused by condensed water splashing to the outside of the flue gas recirculation fan, and better meet user needs.

[0020] Other features and aspects of the present application will become apparent from the following detailed description of exemplary embodiments with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate exemplary embodiments, features, and aspects of the present application and, together with the description, serve to explain the principles of the present application.

[0022] Figure 1 An exploded schematic diagram showing a flue gas recirculation fan according to an embodiment of the present application;

[0023] Figure 2 A partial schematic diagram showing a flue gas recirculation fan according to an embodiment of the present application;

[0024] Figure 3 An exploded schematic diagram showing an existing flue gas recirculation fan. DETAILED DESCRIPTION

[0025] Various exemplary embodiments, features and aspects of the present application will be described in detail below with reference to the accompanying drawings. The same reference numerals in the accompanying drawings represent elements with the same or similar functions. Although various aspects of the embodiments are shown in the accompanying drawings, the drawings are not necessarily drawn to scale unless otherwise specified.

[0026] Among them, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application or simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0027] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0028] The word “exemplary” is used exclusively herein to mean “serving as an example, example, or illustration.” Any embodiment described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments.

[0029] In addition, in order to better illustrate the present application, numerous specific details are given in the following specific embodiments. It should be understood by those skilled in the art that the present application can also be implemented without certain specific details. In some examples, methods, means, components and circuits well known to those skilled in the art are not described in detail in order to highlight the subject matter of the present application.

[0030] like Figure 1 , Figure 2 and Figure 3 As shown, the flue gas recirculation fan comprises: a motor 1, a volute front end plate 3, an impeller 6, a volute 7, a rubber ring 2 and an end cover 5; a first through hole is opened in the horizontal middle of the volute front end plate 3, a second through hole is opened in the horizontal middle of the volute 7, and the size of the first through hole is smaller than that of the second through hole; the motor 1 has a motor shaft, and a third through hole is opened in the horizontal middle of the end cover 5; the inner circumference of the third through hole matches the outer circumference of the motor shaft; the motor shaft sequentially passes through the volute front end plate 3, the end cover 5, the impeller 6 to the middle of the volute 7; the rubber ring 2 is sleeved on the motor shaft, and the rubber ring 2 is arranged between the end cover of the motor 1 and the volute front end plate 3 to seal the gap between the end cover of the motor 1 and the motor shaft. The rubber ring 2 and the motor shaft are interference fit, the inner circumference of the rubber ring 2 is less than or equal to the outer circumference of the first through hole, and the motor shaft passes through the rubber ring 2 to the first through hole; the motor shaft sequentially passes through the rubber ring 2, the volute front end plate 3, the end cover 5, the impeller 6 to the rear of the volute 7.

[0031] The flue gas recirculation fan proposed in this embodiment has a simple connection method, and compared with the traditional flue gas recirculation fan, the sealing of the connection between the motor 1 and the volute 7 of this application is better, and water is not easy to be thrown out from the volute 7 and enter the motor 1 along the motor shaft, which can prevent the motor 1 from burning or bearing damage caused by water ingress during operation. It can also prevent the condensed water from splashing onto the outside of the flue gas recirculation fan, causing the patrol personnel to slip and fall and environmental pollution. This application takes into account the high temperature and high humidity of the boiler flue gas. Therefore, a large amount of condensed water will inevitably be generated during the mixing of boiler flue gas and cold air. Although condensed water cannot be avoided, only blocking the water from flowing out can eliminate the burning of the motor 1 and the injury of personnel. If it is drained to the drainage ditch, this problem can be satisfactorily solved. Therefore, the flue gas recirculation fan is modified as follows. Specifically, by arranging a rubber ring 2 and an end cover 5 on both sides of the front end surface of the volute 7, the sealing of the connection between the first through hole and the motor shaft is better. The existing flue gas recirculation fan uses a skeleton oil seal to be fixedly installed on the end cover of the motor 1, covering the motor shaft. The motor shaft rotates at 1470 rpm. Over time, a gap will be generated between the rubber mouth and the shaft, so that the condensed water splashing at high speed can easily enter the inside of the motor 1. The present application uses the 10mm gap between the end cover of the motor 1 and the front end plate 3 of the volute to install a water-retaining rubber ring 2 on the motor shaft, and the inner diameter of the rubber ring 2 is 2mm smaller than the motor shaft, so that an interference fit is formed between the rubber ring 2 and the shaft after installation, so that even a large amount of water cannot enter the motor 1. It should also be noted that there is a small gap between the rubber ring 2 and the end cover of the motor 1, and the gap is 0.5mm-2mm.

[0032] In one of the specific embodiments, it also includes: white felt 4; white felt 4 is arranged in the circumference of the opening of the front end plate 3 of the volute, and the white felt 4 and the rubber ring 2 are arranged on both sides of the opening of the front end plate 3 of the volute. In this embodiment, it should be noted that the shaft diameter of the motor shaft is Φ38mm, the aperture of the front end plate 3 of the volute (for the motor shaft to extend into the flue gas recirculation fan) is Φ72mm, and there is a 17mm gap between the shaft and the hole. Part of the water thrown out irregularly by the impeller 6 is thrown onto the water retaining ring along this annular gap, and the water retaining ring then throws the water around the flue gas recirculation fan. If a hard sealing material is used, even if an over-matching is used, the water will be thrown out, and this matching will produce friction due to the limited processing accuracy. Therefore, the present application adds a circle of white felt 4 at the shaft hole position of the front end plate 3 of the volute, and the white felt 4 is fixed to the front end plate 3 of the volute, and the inner hole hugs the shaft. When the water reaches the felt, it will flow down along the felt under the action of gravity, and the felt is very soft in texture, and will not cause wear to the shaft even if it hugs the shaft.

[0033] In one specific embodiment, the end cover 5 is arranged on the rear end face of the white felt 4, and the size of the end cover 5 matches the size of the white felt 4. In this embodiment, it should be noted that a nylon end cover 5 is installed on the hub side of the impeller 6 to eliminate the gap, fixed to the front end plate 3 of the volute by a threaded connection, and white felt 4 is filled in the end cover 5 to absorb moisture.

[0034] In one specific embodiment, the rubber ring 2 is arranged in interference connection with the motor shaft; the rubber ring 2 is a water-retaining rubber ring 2, and the outer circumference of the rubber ring 2 is larger than the outer circumference of the first through hole. In this embodiment, it should be noted that the water-retaining rubber ring 2 is installed between the end cover side of the motor 1 and the front end cover 3 of the volute so that it is interference-fitted with the shaft to prevent water from splashing into the motor 1.

[0035] In one specific embodiment, the end cap 5 is a circular structure, the material of the end cap 5 is nylon, and the outer circumference of the end cap 5 is larger than the outer circumference of the first through hole. In this embodiment, it should be noted that the diameter of the third hole opened on the end cap 5 is Φ40mm, and the diameter of the motor shaft is Φ38mm. After the motor shaft passes through the center hole of the end cap, there is a 1mm gap between the two and no contact occurs, but the internal white felt is held on the shaft to block the water droplets that want to be thrown out.

[0036] In one of the specific embodiments, the volute 7 is provided with drainage holes, which are arranged at the bottom of the volute 7 and at the periphery of the volute 7. In this embodiment, it should be noted that during the process of water being thrown out of the volute of the existing flue gas recirculation fan, a portion of the water will remain in the lower part of the volute 7. When the amount of water accumulated is large, the flue gas recirculation fan becomes a water pump and cannot work. This portion of water needs to be discharged regularly. The present application opens drainage holes at the bottom of the volute 7 and installs a drainage pipe to the ditch. When the flue gas recirculation fan is running, the stored water is negative pressure water that cannot be discharged. The speed of the flue gas recirculation fan needs to be regularly reduced each shift so that the water can be discharged.

[0037] In one specific embodiment, it also includes: a drain pipe and a water tank; the size of the drain pipe matches the size of the drain hole, one end of the drain pipe is connected to the drain hole, the other end of the drain pipe is connected to the water tank, and the water tank is set in the ditch. In this embodiment, it should be noted that the water tank is a hollow structure, an opening is set on the water tank, and there is always water in the water tank. Among them, the water tank is set at the end of the drain pipe, and the drain pipe drains water into the water tank. When the water is full, it overflows and flows into the ditch. When the water is not drained, the water in the water tank plays a role in sealing the drain pipe opening to prevent air from being sucked back into the fan.

[0038] In one specific embodiment, the volute 7 is arranged around the volute front end plate 3 , the volute 7 is arranged behind the front end surface of the volute 7 , and the motor 1 is arranged in front of the volute front end plate 3 .

[0039] In one specific embodiment, the first through hole is a circular structure, the second through hole is a circular structure, and the third through hole is a circular structure.

[0040] It should be noted that although the present application is described as an example of a flue gas recirculation fan, those skilled in the art will appreciate that the present application should not be limited thereto. In fact, the user can flexibly set parameters according to personal preferences and / or actual application scenarios, as long as they are reasonable.

[0041] The embodiments of the present application have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The selection of terms used herein is intended to best explain the principles of the embodiments, practical applications, or improvements to the technology in the market, or to enable other persons of ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. A flue gas recirculation fan, characterized in that: Including: motor, volute front end plate, impeller, volute, rubber ring and end cover; A first through hole is opened in the horizontal middle of the front end plate of the volute, and a second through hole is opened in the horizontal middle of the volute, and the size of the first through hole is smaller than that of the second through hole; The motor has a motor shaft, and a third through hole is opened in the horizontal middle of the end cover; the inner circumference of the third through hole matches the outer circumference of the motor shaft; The motor shaft passes through the front end plate of the volute, the end cover, the impeller in sequence to the middle of the volute; The rubber ring is sleeved on the motor shaft, and the rubber ring is arranged between the end cover of the motor and the front end plate of the volute to seal the gap between the end cover of the motor and the motor shaft.

2. The flue gas recirculation fan according to claim 1, characterized in that: Also includes: White felt; the white felt ring is arranged in the circumference of the opening of the front end plate of the volute, and the white felt and the rubber ring are arranged on both sides of the opening of the front end plate of the volute opposite to each other.

3. The flue gas recirculation fan according to claim 2, characterized in that: The end cover is arranged on the rear end surface of the white felt, and the size of the end cover matches the size of the white felt.

4. The flue gas recirculation fan according to claim 1, characterized in that: The rubber ring is arranged in interference connection with the motor shaft; the rubber ring is a water-retaining rubber ring, and the outer circumference of the rubber ring is larger than the outer circumference of the first through hole.

5. The flue gas recirculation fan according to claim 1, characterized in that: The end cover has a circular structure, is made of nylon, and has an outer circumference larger than an outer circumference of the first through hole.

6. The flue gas recirculation fan according to any one of claims 1 to 5, characterized in that: The volute is provided with a drainage hole, the drainage hole is arranged at the bottom of the volute, and the drainage hole is arranged at the outer periphery of the volute.

7. The flue gas recirculation fan according to claim 6, characterized in that: Also includes: A drain pipe and a water tank; the size of the drain pipe matches the size of the drain hole, one end of the drain pipe is connected to the drain hole, the other end of the drain pipe is connected to the water tank, and the water tank is arranged in the ditch.

8. The flue gas recirculation fan according to claim 6, characterized in that: The volute is arranged around the front end plate of the volute, the volute is arranged behind the front end surface of the volute, and the motor is arranged in front of the front end plate of the volute.

9. The flue gas recirculation fan according to claim 6, characterized in that: The first through hole has a circular structure, the second through hole has a circular structure, and the third through hole has a circular structure.

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