Roots blower casing

Abstract

The utility model provides a shell of a Roots blower, and mainly relates to the field of Roots blowers. A Roots blower shell comprises a shell body, an air inlet and an air outlet are formed in the two sides of the shell body respectively, two impellers are arranged in the shell body in the vertical position relation, extending pieces are arranged on the upper side and the lower side of the air inlet, and an air inlet collecting opening is formed between the two extending pieces. A buffer cavity is formed in one side of an air outlet of the shell, arc-shaped perforated plates are arranged on the two sides of the buffer cavity, a plurality of through holes are formed in the perforated plates in an array mode, and an air outlet collecting opening is formed between the two perforated plates. The Roots blower has the beneficial effect that the noise problem of the Roots blower can be fundamentally solved.

Description

Technical Field

[0001] The utility model mainly relates to the field of Roots blowers, in particular to a casing of a Roots blower. Background Art

[0002] Roots blower is widely used in many industries due to its simple structure, low cost, high efficiency, stable flow and many other advantages.

[0003] However, due to the structural characteristics and working principle of the Roots blower, the Roots blower is very noisy when in operation, which greatly limits the application of the blower in more fields. The main source of noise of the Roots blower is also very clear. When the impeller blades pass through the inlet of the shell, the gaps formed between the adjacent blades and the shell are full of gas. Each gap is always in a closed state during the process of delivering gas to the blower outlet as the impeller rotates. The density and pressure of the gas in the gap are equal to the density and pressure of the gas at the inlet of the blower. However, at this time, due to the continuous delivery of gas through the blower, the pressure at the outlet will be 5 to 10kpa higher than the inlet pressure. As the impeller rotates, each closed gap filled with gas density and pressure equal to the inlet of the blower reaches the outlet of the blower and suddenly opens up with the outlet. The high-pressure gas at the outlet will quickly fill the low-pressure gas in the gap. Due to the high speed of the fan, each interval opens very quickly at the outlet. When the high-pressure gas at the outlet fills the low-pressure gas in the interval, a large shock wave will be generated, causing vibrations in the fan casing, pipelines, etc., thus forming a large impact noise. Without taking any noise reduction measures, the impact noise value can reach more than 110 decibels.

[0004] Such a high noise value cannot be used without taking measures. Usually, various noise reduction or noise isolation devices are installed outside the fan body, such as: installing mufflers on the inlet and outlet pipes, wrapping the entire fan with sound-absorbing materials, etc. Although many measures have been taken and a great cost has been spent, and sometimes the investment in noise reduction measures is far higher than the cost of the fan itself, since the noise source has not been fundamentally eliminated, it can only play a role in noise reduction, and cannot completely eliminate the noise. Utility Model Content

[0005] In order to solve the deficiencies of the prior art, the utility model provides a Roots blower casing, which can fundamentally solve the noise problem of the Roots blower.

[0006] In order to achieve the above purpose, the utility model is implemented through the following technical solutions:

[0007] A Roots blower casing comprises a shell, wherein both sides of the shell are provided with an air inlet and an air outlet respectively, the inner cavity of the shell is in an "8"-shaped structure, two impellers are arranged in the shell in an upper and lower positional relationship, extension plates are arranged on the upper and lower sides of the air inlet, an air inlet convergence port is provided between the two extension plates, and the extension trend of the extension plate is consistent with that of the inner cavity of the shell; a buffer cavity is arranged on one side of the air outlet of the shell, arc-shaped porous plates are arranged on both sides of the buffer cavity, a plurality of through holes are arranged in an array on the porous plates, an air outlet convergence port is provided between the two porous plates, and the extension trend of the porous plates is consistent with that of the inner cavity of the shell.

[0008] The end point of the extension piece at one end of the air inlet is the compression starting point, the connection point between the porous plate and the inner cavity of the shell is the sealing end point, when one end of the impeller is located at the compression starting point, the other end of the impeller is located at the sealing end point, and according to the rotation direction of the impeller, the section from the compression starting point to the sealing end point is the sealing section, and the section from the sealing end point to the compression starting point is the reflux compression section.

[0009] The porous plate is detachably connected to the shell.

[0010] The buffer chamber is communicated with the air outlet, and the buffer chamber is separated from the air inlet by two impellers.

[0011] Compared with the prior art, the beneficial effects of the utility model are:

[0012] This invention makes very little change to the Roots blower, only partially transforming and adjusting the arc segment structure inside the casing. It can be upgraded based on the original design, and the source of the blower impact noise can be completely eliminated at a very low cost.

[0013] The Roots blower reduces the pressure shock at the air outlet, thereby reducing the impact noise, and thus can increase the fan speed, so that the fan volume can be reduced while meeting the same air volume or pressure, and the consumption of materials used in fan manufacturing can be reduced, thereby reducing the direct cost of fan manufacturing.

[0014] The structure of this Roots blower reduces noise at the source, and there is no need to excessively install noise-absorbing and isolating facilities, which can reduce greater engineering investment. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Attached Figure 1 It is a schematic diagram of the structure of the utility model;

[0016] Attached Figure 2 It is a schematic diagram of the side view structure of the porous plate of the utility model;

[0017] Attached Figure 3 This is a schematic diagram of the main structure of the porous plate of the utility model;

[0018] Attached Figure 4It is a schematic diagram of the prior art structure of the utility model.

[0019] The numbers shown in the accompanying drawings are: 1, shell; 2, impeller; 3, extension piece; 4, air inlet convergence port; 5, buffer chamber; 6, porous plate; 7, air outlet convergence port; 11, air inlet; 12, air outlet; 31, compression starting point; 61, through hole; 62, sealing stop point. DETAILED DESCRIPTION

[0020] The utility model is further described in conjunction with the accompanying drawings and specific embodiments. It should be understood that these embodiments are only used to illustrate the utility model and are not used to limit the scope of the utility model. In addition, it should be understood that after reading the content taught by the utility model, those skilled in the art can make various changes or modifications to the utility model, and these equivalent forms also fall within the scope defined by this application.

[0021] like Figure 1-3 As shown, the housing of a Roots blower of the utility model comprises a housing 1, and the housing 1 has an air inlet 11 and an air outlet 12 on both sides thereof, and the inner cavity of the housing 1 is in an "8"-shaped structure, and two impellers 2 are arranged in an upper and lower position relationship in the housing 1. The upper and lower parts of the housing 1 are both circular, so that the impeller 2 installed therein can rotate stably to complete air supply.

[0022] Extension pieces 3 are provided on the upper and lower sides of the air inlet 11, and an air inlet converging port 4 is provided between the two extension pieces 3, and the extension piece 3 is consistent with the extension trend of the inner cavity of the housing 1. The upper and lower inner arcs of the Roots blower housing are extended toward the blower inlet by the extension piece 3, the width of the air inlet 11 at the inner arc of the housing is narrowed, and the length of the inner arc that matches the impeller is increased. A buffer cavity 5 is provided on one side of the air outlet 12 of the housing 1, and arc-shaped porous plates 6 are provided on both sides of the buffer cavity 5, and the porous plates 6 are consistent with the extension trend of the inner cavity of the housing 1. An air outlet converging port 7 is provided between the two porous plates 6, and the porous plate 6 extends the upper and lower inner arcs of the Roots blower housing toward the blower outlet, narrows the width of the air outlet 12 at the inner arc of the housing, and increases the length of the inner arc that matches the impeller. Specifically, the porous plate 6 is detachably connected to the housing 1, so that it is convenient to replace the porous plate 6 with different apertures or different numbers of holes to adapt to various working conditions of the blower at any time.

[0023] Specifically, the buffer chamber 5 is communicated with the air outlet 12 , and the buffer chamber 5 is separated from the air inlet 11 by two impellers 2 .

[0024] The porous plate 6 is provided with a plurality of through holes 61 in an array, and the buffer cavity 5 is connected with the inner cavity of the shell 1 through the through holes 61 .

[0025] The end point of the extension piece 3 located at one end of the air inlet convergence port 4 is the compression starting point 31, and the connection point between the porous plate 6 and the inner cavity of the shell 1 is the sealing stop point 62. When one end of the impeller 2 is located at the compression starting point 31, the other end of the impeller 2 is located at the sealing stop point 62. According to the rotation direction of the impeller 2, the section from the compression starting point 31 to the sealing stop point 62 is the sealing section, and the section from the sealing stop point 62 to the compression starting point 31 is the reflux compression section.

[0026] During the operation of the Roots blower, when the blades of the impeller 2 pass through the air inlet convergence port 4, the gaps formed between the adjacent blades and the housing are full of gas. In the process of forming a closed chamber that rotates with the impeller 2 to deliver gas to the blower outlet 12, after the apex of the front impeller blade in the closed chamber exceeds the compartment sealing stop point 62 and enters the arc segment of the porous plate 6, a part of the through holes 61 on the porous plate 6 is connected to the closed chamber, and the high-pressure gas on the side of the blower outlet 12 begins to be injected into the closed chamber from the part of the through holes 61 of the porous plate 6, and the low-pressure gas in the closed chamber is compressed, and the density and pressure begin to increase. As the impeller rotates continuously, the number of holes on the porous plate 6 connected to the closed chamber will gradually increase, and the return gas flow rate will also gradually increase, until the pressure in the closed chamber is equal to or close to the pressure at the fan outlet 12. The apex of the front impeller blade in the closed chamber passes through the side edge of the porous plate close to the fan outlet 12, so that the entire chamber is completely opened to the fan outlet 12, and the gas that has been compressed to a pressure equal to or close to that at the fan outlet 12 is discharged into the fan outlet pipe.

[0027] The process of each closed chamber passing through the arc segment of the perforated plate 6 of the inner shell of the fan in turn is the process of the high-pressure gas on the side of the fan outlet 12 being gradually injected into the compartment to compress the gas in the closed chamber. When the connection is just started, the chamber gas density is the lowest and the pressure is the lowest, and the pressure difference with the orifice plate reflux chamber is the largest. However, since the number of holes connected at this time is small, the flow of the reflux gas will also be small. And after being diverted by the orifice plate, the impact energy is lost and the density and pressure of the gas in the compartment can only be increased silently. As the impeller 2 rotates continuously, the number of through holes 61 connected to the closed chamber will gradually increase, but at this time the gas density and pressure in the compartment have been improved, reducing the pressure difference between the reflux gas and the compartment, and the reflux gas also loses the impact energy. Therefore, the reflux gas flow rate will not cause too much impact in the process of gradually increasing, until the pressure of the closed chamber is equal to or close to the pressure of the fan outlet, and the pressure difference between the compartment and the fan outlet is almost zero after the compartment and the fan outlet are fully opened, and no impact will be generated. Therefore, the invention completely eliminates the root cause of the impact noise of the Roots blower.

[0028] The use of this technology will fundamentally eliminate the impact noise of Roots blowers. Roots blowers without impact noise have changed from high-noise manufacturers to environmentally friendly ones. This will greatly expand the scope of use and dramatically increase the amount of use, and will also play a greater role in promoting social production.

[0029] Since the noise source of traditional Roots blowers is the pressure difference at the air outlet, the use of this technology to manufacture Roots blowers without impact noise can appropriately increase the blower outlet pressure without having to worry about the impact noise caused by the pressure difference, and reduce the number of series connections when used in high-pressure environments, thereby reducing the space occupied by the blower and reducing investment costs.

[0030] Roots blowers without impact noise can increase the blower speed again without worrying about the noise. This can reduce the size of the blower while meeting the same air volume or pressure, reduce the consumption of materials used in the manufacture of the blower, and thus reduce the direct cost of blower manufacturing.

[0031] Furthermore, the Roots blower housing is also applicable to three-blade blowers or multi-blade blowers, and it is only necessary to adjust the position and size of the porous plate 6 according to the number of blades.

Claims

1. A Roots blower casing, comprising a casing (1), wherein the casing (1) has an air inlet (11) and an air outlet (12) on both sides thereof, the inner cavity of the casing (1) is in an "8"-shaped structure, and two impellers (2) are arranged in an upper and lower position relationship in the casing (1), characterized in that: Extension pieces (3) are arranged on the upper and lower sides of the air inlet (11), an air inlet convergence port (4) is provided between the two extension pieces (3), and the extension trend of the extension piece (3) is consistent with that of the inner cavity of the shell (1); a buffer cavity (5) is arranged on one side of the air outlet (12) of the shell (1), arc-shaped porous plates (6) are arranged on both sides of the buffer cavity (5), a plurality of through holes (61) are arranged in an array on the porous plates (6), an air outlet convergence port (7) is provided between the two porous plates (6), and the extension trend of the porous plates (6) is consistent with that of the inner cavity of the shell (1).

2. A Roots blower housing according to claim 1, characterized in that: The end point of the extension piece (3) located at one end of the air inlet convergence port (4) is the compression starting point (31), and the connection point between the porous plate (6) and the inner cavity of the shell (1) is the sealing stop point (62). When one end of the impeller (2) is located at the compression starting point (31), the other end of the impeller (2) is located at the sealing stop point (62). According to the rotation direction of the impeller (2), the section from the compression starting point (31) to the sealing stop point (62) is the sealing section, and the section from the sealing stop point (62) to the compression starting point (31) is the reflux compression section.

3. The Roots blower housing according to claim 1, characterized in that: The porous plate (6) is detachably connected to the shell (1).

4. The Roots blower housing according to claim 1, characterized in that: The buffer chamber (5) is connected to the air outlet (12), and the buffer chamber (5) is separated from the air inlet (11) by two impellers (2).

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