A countercurrent noise reduction Roots pump

Abstract

The present application relates to a countercurrent noise reduction Roots pump, which comprises a housing and a working chamber. In the working chamber, a driving impeller and a driven impeller are symmetrically arranged in a conjugate manner. Axial ends of the driving impeller and the driven impeller are respectively provided with wall plates fixedly connected to the housing. A low-pressure air inlet end is arranged on one side of the housing, and a high-pressure exhaust end is arranged on the other side of the housing. A low-pressure air inlet is formed on one side of the working chamber close to the low-pressure air inlet end, and a high-pressure exhaust port is formed on one side of the working chamber far from the low-pressure air inlet. A high-pressure exhaust chamber is arranged outside the high-pressure exhaust port. A pair of countercurrent noise reduction cavities are symmetrically arranged on the housing. A countercurrent noise reduction hole is formed on the side wall of each countercurrent noise reduction cavity close to the working chamber. The countercurrent noise reduction holes respectively communicate the countercurrent noise reduction cavities with the working chamber. The opening area of the countercurrent noise reduction holes conforms to the laws of thermodynamics and fluid mechanics, and the reflux speed of the high-pressure gas in the high-pressure exhaust chamber into the elementary volume is controlled by using the area of the countercurrent noise reduction holes. The present application has the advantage of significantly reducing the noise of the Roots pump.

Description

Technical Field

[0001] This application relates to the field of roots pump technology, and in particular to a countercurrent noise reduction roots pump. Background Art

[0002] A roots pump is a positive displacement pump that uses two rotors with conjugate leaf shapes to compress and transport gas through relative movement within the working chamber. The impeller profile of the rotor usually adopts involute, cycloid or circular envelope profile, and when the two impellers rotate to any position driven by the synchronous gear, the profiles of the two impellers can maintain a certain very small gap. At the same time, the gap between the outer edges of the impeller peaks of the two impellers and the working chamber of the roots pump, and the gap between the end faces of the two impellers and the corresponding wall plates are also very small, so as to effectively control the leakage of high-pressure gas in the high-pressure chamber and maintain the efficient operation of the roots pump.

[0003] Currently, a kind of roots pump, such as Figure 1 shown, includes a housing 3, a working chamber 5 arranged inside the housing 3. Wall plates 4 are respectively arranged on both end faces of the working chamber 5. A main oil tank 1 is arranged outside one of the wall plates 4, and a secondary oil tank 2 is arranged outside the other wall plate 4; symmetrically arranged in the working chamber 5 are an active impeller 7 and a driven impeller 8 with the same structure. External power is input through the coupling at the shaft end of the active impeller 7, and the active impeller 7 drives the driven impeller 8 to rotate synchronously through a synchronous gear.

[0004] As Figure 2 shown, the active impeller 7 includes a first active blade 71, a second active blade 72 and a third active blade 73. The first active blade 71 includes a first active blade peak 711, the second active blade 72 includes a second active blade peak 721, and the third active blade 73 includes a third active blade peak 731; the driven impeller 8 includes a first driven blade 81, a second driven blade 82 and a third driven blade 83. The first driven blade 81 includes a first driven blade peak 811, the second driven blade 82 includes a second driven blade peak 821, and the third driven blade 83 includes a third driven blade peak 831. One side of the housing 3 is provided with a low-pressure air inlet end 31, the other side of the housing 3 is provided with a high-pressure exhaust end 32, a low-pressure air inlet 51 is arranged on the side of the working chamber 5 close to the low-pressure air inlet end 31, a high-pressure exhaust port 52 is opened on the other side of the working chamber 5, and a high-pressure exhaust chamber 6 is arranged outside the high-pressure exhaust port 52.

[0005] As Figure 2As shown, the edge of the low-pressure air inlet 51 is set as A, the position 120° away from A on the inner wall of the working chamber 5 is set as B', and the junction of the inner wall of the working chamber 5 and the high-pressure exhaust port 52 is set as C. As the first active lobe peak 711 rotates towards the inner wall of the working chamber 5 to start suction, when the first active lobe peak 711 approaches the edge A of the low-pressure air inlet 51, at this time, an approximately airtight cavity is formed by the first active lobe 71, the second active lobe 72, the working chamber 5 and the wall panel 4, and this cavity is the elementary volume 9. At the same time, since the first active lobe peak 711 approaches the edge A of the low-pressure air inlet 51, the gas flow from the low-pressure air inlet 51 into the elementary volume 9 is blocked, and at this time, the pressure in the elementary volume 9 is approximately equal to the pressure at the low-pressure air inlet 51.

[0006] As Figure 2 shown, when the first active lobe peak 711 approaches the edge A of the low-pressure air inlet 51, the second active lobe peak 721 just approaches the position B' on the inner wall of the working chamber 5. At this time, the formed elementary volume 9 is approximately an airtight cavity. Since the gaps between the meshing parts of the active impeller 7 and the driven impeller 8, between the lobe peaks of the active impeller 7 and the driven impeller 8 and the inner edge of the working chamber 5, and between the end faces of the active impeller 7 and the driven impeller 8 and the wall panels 4 are very small, the backflow leakage of the high-pressure gas in the high-pressure exhaust chamber 6 into the elementary volume 9 is restricted. Therefore, the high-pressure gas will not cause obvious backflow gas impact on the elementary volume 9.

[0007] As Figure 3 shown, the active impeller 7 continues to rotate, driving the air in the elementary volume 9 to move towards the high-pressure exhaust port 52. When the second active lobe peak 721 approaches the junction C position of the high-pressure exhaust port 52 and the inner wall of the working chamber 5, at this time, the gaps between the second active lobe peak 721 and the inner wall C of the working chamber 5 and between the end face of the second active lobe 72 and the two wall panels 4 are very small, and the backflow leakage of the high-pressure gas in the high-pressure exhaust chamber 6 into the elementary volume 9 is still very small, and the backflow gas impact is still not obvious.

[0008] As Figure 4 shown, as the second active lobe peak 721 continues to rotate, the gap between the second active lobe peak 721 and the inner wall C of the working chamber 5 increases rapidly, so that the elementary volume 9 is communicated with the high-pressure exhaust port 52. At this time, the high-temperature and high-pressure gas in the high-pressure exhaust chamber 6 flows back into the elementary volume 9 through the rapidly increasing gap, making the pressure value in the elementary volume 9 increase rapidly to the pressure value in the high-pressure exhaust chamber 6, thus generating a huge backflow gas impact noise and significantly increasing the operating noise of the Roots pump. At the same time, since the high-temperature and high-pressure gas in the high-pressure exhaust chamber 6 flows back and compresses, the exhaust temperature further increases, shortening the service life of the Roots pump.

[0009] As the driving impeller 7 and the driven impeller 8 continue to rotate synchronously and conjugately, the high-pressure gas in the elementary volume 9 is continuously squeezed into the high-pressure exhaust cavity 6. At the same time, the low-pressure gas at the low-pressure inlet 51 is continuously sucked into the subsequently formed elementary volume 9. Since the driving impeller 7 and the driven impeller 8 in the working chamber 5 are conjugately and symmetrically arranged, the operating principles of the two conjugate and symmetrical parts in the working chamber 5 are the same, thereby realizing the continuous pressurized transportation of the low-pressure gas by the Roots pump.

[0010] Therefore, it can be seen that how to make the reflux process of the high-pressure gas in the high-pressure exhaust cavity 6 tend to be gentle and stable and reduce the intensity of the high-pressure gas reflux impact is the key to reducing the operating noise of the Roots pump. At the same time, reducing the intensity of the high-pressure gas reflux impact can effectively reduce the impact damage caused by the high-pressure gas reflux impact to the inside of the working chamber 5, thereby prolonging the service life of the Roots pump and improving the operating stability of the Roots pump. Summary of the Invention

[0011] In order to weaken the intensity of the high-pressure gas reflux impact and reduce the operating noise of the Roots pump, the present application provides a Roots pump with reverse flow noise reduction, adopting the following technical solutions:

[0012] A countercurrent noise reduction Roots pump, comprising a housing and a working chamber disposed within the housing. A driving impeller and a driven impeller are symmetrically and conjugately disposed within the working chamber. Axial ends of the driving impeller and the driven impeller are respectively provided with a wall plate fixedly connected to the housing. One side of the housing is provided with a low-pressure air inlet end, and the other side of the housing is provided with a high-pressure exhaust end. A low-pressure air inlet is opened on a side of the working chamber close to the low-pressure air inlet end, and a high-pressure exhaust port is opened on a side of the working chamber away from the low-pressure air inlet. A high-pressure exhaust chamber is disposed outside the high-pressure exhaust port. A pair of countercurrent noise reduction cavities are symmetrically disposed outside the working chamber within the housing. Side walls of each countercurrent noise reduction cavity close to the working chamber are symmetrically provided with countercurrent noise reduction holes. The countercurrent noise reduction holes are designed according to the principles of fluid mechanics and thermodynamics. The countercurrent noise reduction holes respectively communicate the countercurrent noise reduction cavities with the working chamber; outer edges of the blade peaks of the driving impeller and the driven impeller are disposed in close proximity to the inner edge of the working chamber; an outer arc surface of the blade peak is set as arc surface ab, a radian angle corresponding to the arc surface ab is γ, a width of the countercurrent noise reduction hole is d, an outer edge radius of the blade peaks of the driving impeller and the driven impeller is R, an edge of the inner wall of the working chamber at the low-pressure air inlet is set as A, a center line of the opening position of the countercurrent noise reduction hole is set as B, an edge of the inner wall of the working chamber at the high-pressure exhaust port is set as C, a radian angle between A and B is α, and α = (2π) / n – γ / 2, where n is the number of impeller heads, and d ≤ γR; when the b side of the outer arc surface of the first blade peak just rotates to the intake end edge A of the inner wall of the working chamber at the low-pressure air inlet (51), the center of the outer arc surface ab of the second blade peak adjacent to the first blade peak just rotates to the center line B of the opening position of the countercurrent noise reduction hole on the inner wall of the working chamber. The first blade peak, the second blade peak, the wall plate, and the inner wall of the working chamber together form a basic volume. Since the width d of the countercurrent noise reduction hole (11) ≤ γR, the arc length of the arc surface ab is greater than or equal to the width d of the countercurrent noise reduction hole, and the outer arc surface ab of the second blade peak just blocks the countercurrent noise reduction hole (11); at the moment when the a side of the outer arc surface ab of the second blade peak rotates away from C, the pressure within the basic volume is close to or equal to the pressure within the high-pressure exhaust chamber.

[0013] By adopting the above technical solution, the roots pump is started, and the driving impeller drives the driven impeller to rotate synchronously. When the b side of the outer arc surface of the first lobe peak just rotates to the intake end edge A of the inner wall of the working chamber at the low-pressure intake port, at this time, the center of the outer arc surface ab of the second lobe peak just rotates to the center line B of the position where the countercurrent noise reduction hole is opened on the inner wall of the working chamber. At this time, the first driving blade, the second driving blade, the wall plate and the inner wall of the working chamber jointly form an elementary volume. Since the width d of the countercurrent noise reduction hole ≤ γR, and the arc length of the arc surface ab is greater than or equal to the width d of the countercurrent noise reduction hole, at this time, the outer arc surface ab of the second lobe peak just blocks the countercurrent noise reduction hole, so that the high-pressure gas in the high-pressure chamber cannot flow back into the elementary volume. At this time, the air pressure in the elementary volume is close to or equal to the air pressure of the low-pressure intake port. As the driving impeller and the driven impeller continue to rotate, the outer arc surface ab of the second lobe peak evenly sweeps across the countercurrent noise reduction hole and makes the countercurrent noise reduction hole communicate the countercurrent noise reduction cavity with the elementary volume respectively. At this time, the high-pressure gas in the countercurrent noise reduction cavity is gradually countercurrent pressurized into the elementary volume under the control of the area of the countercurrent noise reduction hole. When the a side of the outer arc surface ab of the second lobe peak rotates to the edge C of the inner wall of the working chamber on the side of the high-pressure exhaust port, at this time, the air pressure in the elementary volume is close to or equal to the pressure in the high-pressure exhaust chamber. At the moment when the a side of the outer arc surface ab of the second lobe peak turns away from C, since the pressure in the elementary volume is close to or equal to the pressure in the high-pressure exhaust chamber, the impact effect caused by the backflow of the high-pressure gas is greatly reduced, achieving the effect of effectively reducing the noise of the roots pump. At the same time, the damage to the working chamber caused by the backflow impact of the high-pressure gas is also reduced, improving the operation stability and service life of the roots pump. The working principle of the other working chamber and the process of pressure change in the elementary volume are the same.

[0014] Optionally, the countercurrent noise reduction cavity is arranged on the outer wall of the working chamber of the housing and is directly communicated with the high-pressure exhaust chamber.

[0015] By adopting the above technical solution, when the outer arc surface ab of the second lobe peak evenly sweeps across the countercurrent noise reduction hole and makes the countercurrent noise reduction hole communicate the countercurrent noise reduction cavity with the elementary volume respectively, the high-pressure gas in the high-pressure exhaust chamber is gradually countercurrent pressurized into the elementary volume under the control of the area of the countercurrent noise reduction hole. When the a side of the outer arc surface ab of the second lobe peak rotates to the edge C of the inner wall of the working chamber on the side of the high-pressure exhaust port, at this time, the air pressure in the elementary volume is close to or equal to the pressure in the high-pressure exhaust chamber, so that the impact effect caused by the backflow of the high-pressure gas in the high-pressure exhaust chamber into the elementary volume is greatly reduced, achieving the effect of effectively reducing the noise of the roots pump.

[0016] Optionally, the countercurrent noise reduction cavity is arranged on the outer wall of the working chamber of the housing and is separated from the high-pressure exhaust chamber. An external connection end is arranged at one end of the countercurrent noise reduction cavity away from the countercurrent noise reduction hole, and an external countercurrent pressurized gas source is communicated with the external connection end.

[0017] By adopting the above technical solution, when the outer arc surface ab of the second lobe peak uniformly sweeps across the countercurrent noise reduction holes and enables the countercurrent noise reduction holes to connect the high-pressure gas in the countercurrent noise reduction cavity with the elementary volume respectively, due to being controlled by the area of the countercurrent noise reduction holes, the external countercurrent booster gas source connected to the external connection end gradually countercurrent boosts into the elementary volume. When the a side of the outer arc surface ab of the second lobe peak rotates to the edge C of the inner wall of the working cavity on the side of the high-pressure exhaust port, at this time, the air pressure in the elementary volume is close to or equal to the pressure in the high-pressure exhaust cavity, so as to effectively reduce the impact effect caused by the backflow of the high-pressure gas in the countercurrent noise reduction cavity into the elementary volume, and achieve the effect of significantly reducing the noise of the Roots pump.

[0018] Optionally, the external countercurrent booster gas source is the low-temperature and high-pressure gas formed by cooling the high-temperature and high-pressure gas led from the high-pressure exhaust cavity through a cooling device or the external atmospheric gas source with a relatively low temperature.

[0019] By adopting the above technical solution, since the temperature of the low-temperature and high-pressure gas source formed by cooling the high-temperature and high-pressure gas led from the high-pressure exhaust cavity through a cooling device is significantly lower than the temperature of the compressed gas in the high-pressure exhaust cavity, therefore, using the low-temperature gas source cooled by cooling to countercurrent boost into the elementary volume can not only effectively weaken the impact effect caused by the backflow of the high-pressure gas in the high-pressure exhaust cavity into the elementary volume to reduce the noise of the Roots pump, but also effectively reduce the working temperature of the Roots pump; when the Roots pump is used as a Roots pump directly exhausting to the atmosphere, using the atmospheric gas source to countercurrent boost into the elementary volume, similarly, because the temperature of the atmospheric gas source is also significantly lower than the temperature of the compressed gas in the high-pressure exhaust cavity, it can also effectively reduce the working temperature of the Roots pump while reducing the noise of the Roots pump.

[0020] Optionally, the countercurrent noise reduction cavity is arranged in the wall panel, and a pair of countercurrent noise reduction holes communicating with the working cavity are symmetrically opened on one side wall of the countercurrent noise reduction cavity in the wall panel facing the working cavity of the casing.

[0021] By adopting the above technical solution, when the highest point of the outer edge of the first lobe peak rotates to the edge A of the low-pressure air inlet, the end face of the second active lobe just blocks the corresponding countercurrent noise reduction hole, and at this time, the elementary volume is formed. The impeller continues to rotate, the end face of the second active lobe begins to turn away from the corresponding countercurrent noise reduction hole, the countercurrent noise reduction hole gradually opens, and the high-pressure gas in the countercurrent noise reduction cavity in the wall panel is controlled by the area of the countercurrent noise reduction hole and gradually countercurrent boosts into the elementary volume through the countercurrent noise reduction hole; when the highest point of the outer edge of the second lobe peak rotates to the edge C of the inner wall of the working cavity, at this time, the air pressure in the elementary volume is close to or equal to the pressure in the high-pressure exhaust cavity. At the moment when the highest point of the second lobe peak turns away from point C, since the pressure in the elementary volume is close to the pressure in the high-pressure exhaust cavity, the impact effect caused by the backflow of the high-pressure gas is significantly reduced, and the effect of effectively reducing the noise of the Roots pump is achieved.

[0022] Optionally, the countercurrent noise reduction cavity provided on the wall panel is directly communicated with the high-pressure exhaust cavity, and the countercurrent noise reduction cavity communicates with the high-pressure exhaust end through the high-pressure exhaust cavity.

[0023] By adopting the above technical solution, when the end face of the second active blade evenly sweeps across the countercurrent noise reduction holes and communicates the countercurrent noise reduction cavity with the elementary volume through the countercurrent noise reduction holes, the high-pressure gas in the high-pressure exhaust cavity is gradually countercurrently pressurized into the elementary volume under the control of the area of the countercurrent noise reduction holes. When the outermost highest point of the second blade peak rotates to the edge C of the inner wall of the working cavity on the side of the high-pressure exhaust port, the air pressure in the elementary volume is close to or equal to the pressure in the high-pressure exhaust cavity at this time, thereby greatly reducing the impact effect caused by the backflow of the high-pressure gas in the high-pressure exhaust cavity into the elementary volume, and achieving the effect of effectively reducing the noise of the Roots pump.

[0024] Optionally, the countercurrent noise reduction cavity in the wall panel is separated from the high-pressure exhaust cavity. A pair of external connection ends communicating with the countercurrent noise reduction cavity are symmetrically arranged on both sides of the wall panel, and an external countercurrent pressurizing gas source is communicated with the external connection ends.

[0025] By adopting the above technical solution, when the end face of the second active blade evenly sweeps across the countercurrent noise reduction holes and communicates the countercurrent noise reduction cavity with the elementary volume through the countercurrent noise reduction holes, the external countercurrent pressurizing gas source communicated with the external connection ends conveys high-pressure gas to the countercurrent noise reduction chamber and is gradually countercurrently pressurized into the elementary volume under the control of the area of the countercurrent noise reduction holes. When the outermost highest point of the second blade peak rotates to the edge C of the inner wall of the working cavity, the air pressure in the elementary volume is close to or equal to the pressure in the high-pressure exhaust cavity at this time, thereby effectively reducing the impact effect caused by the backflow of the high-pressure gas in the high-pressure exhaust cavity into the elementary volume, and achieving the effect of significantly reducing the noise of the Roots pump.

[0026] Optionally, the external countercurrent pressurizing gas source is low-temperature high-pressure gas formed by cooling high-temperature high-pressure gas introduced from the high-pressure exhaust cavity through a cooling device or an external atmospheric gas source with a relatively low temperature.

[0027] By adopting the above technical solution, since the temperature of the low-temperature high-pressure gas source formed by cooling the high-temperature high-pressure gas introduced from the high-pressure exhaust cavity through a cooling device is significantly lower than the temperature of the compressed gas in the high-pressure exhaust cavity, therefore, using the low-temperature high-pressure gas source cooled by cooling to countercurrently pressurize into the elementary volume can not only effectively weaken the impact effect caused by the backflow of the high-pressure gas in the high-pressure exhaust cavity into the elementary volume to reduce the noise of the Roots pump, but also effectively reduce the working temperature of the Roots pump; when the Roots pump is used as a Roots pump directly exhausting to the atmosphere, using the atmospheric gas source to countercurrently pressurize into the elementary volume, similarly, because the temperature of the atmospheric gas source is also significantly lower than the temperature of the compressed gas in the high-pressure exhaust cavity, it can also effectively reduce the working temperature of the Roots pump while reducing the noise of the Roots pump.

[0028] In summary, the present application includes at least one of the following beneficial technical effects:

[0029] 1. A countercurrent noise reduction cavity is provided, and countercurrent noise reduction holes communicating the working cavity with the countercurrent noise reduction cavity are opened on the inner wall of the working cavity. The gas in the countercurrent noise reduction cavity is gradually countercurrent pressurized into the basic volume by controlling the area of the countercurrent noise reduction holes, so that when the basic volume communicates with the high-pressure exhaust cavity, the pressure in the basic volume is close to or equal to the pressure in the high-pressure exhaust cavity, thereby reducing the impact effect caused by the reflux of high-pressure gas and effectively reducing the noise of the Roots pump;

[0030] 2. The countercurrent noise reduction cavity is separated from the high-pressure exhaust cavity, and an external countercurrent pressurization gas source is communicated at the outer end of the countercurrent noise reduction cavity. The external countercurrent pressurization gas source is gradually countercurrent pressurized into the basic volume by controlling the area of the countercurrent noise reduction holes, thereby reducing the noise of the Roots pump;

[0031] 3. By providing a countercurrent noise reduction cavity inside the wall panel, this countercurrent noise reduction cavity communicates with the high-pressure exhaust cavity, and a pair of countercurrent noise reduction holes are symmetrically opened on the side wall of the wall panel facing the working cavity. The high-pressure gas in the high-pressure exhaust cavity passes through the countercurrent noise reduction cavity and is gradually countercurrent pressurized into the basic volume by controlling the area of the countercurrent noise reduction holes, thereby reducing the impact effect caused by the reflux of the high-pressure gas in the high-pressure exhaust cavity and effectively reducing the noise of the Roots pump;

[0032] 4. The countercurrent noise reduction cavity in the wall panel is separated from the high-pressure exhaust cavity, and the countercurrent noise reduction cavity is communicated with an external countercurrent pressurization gas source. The high-pressure gas in the external countercurrent pressurization gas source is gradually countercurrent pressurized into the basic volume under the control of the area of the countercurrent noise reduction holes, achieving the effect of reducing the noise of the Roots pump;

[0033] 5. The provided external countercurrent pressurization gas source can also be high-temperature and high-pressure gas introduced from the high-pressure exhaust cavity. This high-temperature and high-pressure gas is cooled by a cooling device to form low-temperature and high-pressure gas. The low-temperature and high-pressure gas source with cooling and temperature reduction is used to countercurrent pressurize the basic volume, which can reduce the working temperature of the Roots pump while reducing the noise of the Roots pump;

[0034] 6. When the Roots pump is used as a Roots pump directly exhausting to the atmosphere, the provided external countercurrent pressurization gas source can be an external atmospheric gas source. Since the temperature of the external atmospheric gas source is lower than the temperature of the gas in the high-pressure exhaust cavity, the working temperature of the Roots pump can be effectively reduced while reducing the noise of the Roots pump. Description of the Drawings

[0035] Figure 1 is the overall structural cross-sectional view of the Roots pump in the background art of the present application.

[0036] Figure 2 is the cross-sectional view for reflecting the initial position of the basic volume in the working cavity of the Roots pump in the background art of the present application.

[0037] Figure 3 It is a cross-sectional view of the working state in the background art of the present application for showing the working state when the elementary volume in the working chamber is about to communicate with the high-pressure exhaust chamber.

[0038] Figure 4 It is a cross-sectional view of the working state in the background art of the present application for showing the working state at the moment when the elementary volume in the working chamber communicates with the high-pressure exhaust chamber.

[0039] Figure 5 It is a cross-sectional view of the present application in Embodiment 1 for showing the positional relationship between the countercurrent noise reduction cavity and the countercurrent noise reduction holes.

[0040] Figure 6 It is a sectional view of the housing of a countercurrent noise reduction Roots pump and the structure of the countercurrent noise reduction holes in Embodiment 1 of the present application.

[0041] Figure 7 It is a cross-sectional view of the positional relationship between the elementary volume and the initial position of the working chamber in Embodiment 1 of the present application.

[0042] Figure 8 It is a cross-sectional view of the working state when the elementary volume is about to communicate with the high-pressure exhaust chamber in Embodiment 1 of the present application.

[0043] Figure 9 It is a cross-sectional view of the working state for showing the communication between the elementary volume and the high-pressure exhaust chamber in Embodiment 1 of the present application.

[0044] Figure 10 It is a cross-sectional view of the present application in Embodiment 2 for showing the internal structure of the housing.

[0045] Figure 11 It is a sectional view of the present application in Embodiment 3 for showing the positional relationship between the plugging cavity and the countercurrent noise reduction holes.

[0046] Figure 12 It is a schematic structural diagram and a sectional view in the A-A direction of the present application in Embodiment 4 for showing the positional relationship between the spaced plugging cavities and the countercurrent noise reduction holes.

[0047] Figure 13 It is a cross-sectional view of the internal structure in which the countercurrent noise reduction cavity and the high-pressure exhaust chamber are separated in Embodiment 5 of the present application.

[0048] Figure 14 It is a cross-sectional view of the internal structure of the housing of a countercurrent noise reduction Roots pump in Embodiment 6 of the present application.

[0049] Figure 15 It is a schematic diagram of the positional relationship between the countercurrent noise reduction cavity and the wall panel of a countercurrent noise reduction Roots pump in Embodiment 7 of the present application.

[0050] Figure 16It is a cross-sectional view of the initial state of the elementary volume formation in the working chamber in Embodiment 7 of the present application.

[0051] Figure 17 It is a cross-sectional view of the working state in Embodiment 7 of the present application for showing the countercurrent pressurization of high-temperature and high-pressure gas into the elementary volume through the countercurrent noise reduction holes.

[0052] Figure 18 It is a cross-sectional view of the working state in Embodiment 7 of the present application for showing that the elementary volume is about to communicate with the high-pressure exhaust cavity.

[0053] Figure 19 It is a schematic diagram showing the positional relationship between the countercurrent noise reduction cavity and the wall plate, and between the countercurrent noise reduction holes and the wall plate in a countercurrent noise reduction Roots pump according to Embodiment 8 of the present application.

[0054] Explanation of reference numerals: 1, main oil tank; 2, auxiliary oil tank; 3, housing; 31, low-pressure air inlet end; 32, high-pressure exhaust end; 4, wall plate; 5, working chamber; 51, low-pressure air inlet; 52, high-pressure exhaust port; 6, high-pressure exhaust cavity; 7, driving impeller; 71, first driving vane; 711, first driving vane peak; 72, second driving vane; 721, second driving vane peak; 73, third driving vane; 731, third driving vane peak; 8, driven impeller; 81, first driven vane; 811, first driven vane peak; 82, second driven vane; 821, second driven vane peak; 83, third driven vane; 831, third driven vane peak; 9, elementary volume; 10, countercurrent noise reduction cavity; 11, countercurrent noise reduction holes; 12, external connection end; 13, plugging cavity; 131, processing window. Detailed implementation manners

[0055] The following further elaborates on the present application in conjunction with the attached Figure 1-19 to make a more detailed description of the present application.

[0056] The embodiments of the present application disclose a countercurrent noise reduction Roots pump.

[0057] Embodiment 1

[0058] A countercurrent noise reduction Roots pump, referring to Figure 5 and Figure 6 , includes a housing 3. One side of the housing 3 is fixedly connected with a low-pressure air inlet end 31, and the other side of the housing 3 is fixedly connected with a high-pressure exhaust end 32. There are two high-pressure exhaust ends 32 symmetrically arranged.

[0059] Referring to Figure 5, a working chamber 5 is provided inside the housing 3. The driving impeller 7 and the driven impeller 8 are conjugately and symmetrically arranged inside the working chamber 5. The driving impeller 7 includes a first driving blade 71, a first driving blade peak 711, a second driving blade 72, a second driving blade peak 721, a third driving blade 73, and a third driving blade peak 731. The driven impeller 8 includes a first driven blade 81, a first driven blade peak 811, a second driven blade 82, a second driven blade peak 821, a third driven blade 83, and a third driven blade peak 831. The outer edges of the blade peaks of the driving impeller 7 and the driven impeller 8 are both arranged in close proximity to the inner edge of the working chamber 5. The two parts of the driving impeller 7 and the driven impeller 8 that are conjugately and symmetrically arranged inside the working chamber 5 have the same working operation principle.

[0060] Refer to Figure 5 and Figure 6 , on one side of the working chamber 5 close to the low-pressure intake end 31, a low-pressure intake port 51 is provided. On the side of the working chamber 5 away from the low-pressure intake port 51, a high-pressure exhaust port 52 is provided. On the outside of the high-pressure exhaust port 52, a high-pressure exhaust chamber 6 is provided. The high-pressure exhaust chamber 6 communicates with the outside through the high-pressure exhaust end 32.

[0061] Refer to Figure 5 and Figure 6 , a pair of countercurrent noise reduction cavities 10 are symmetrically arranged between the outer wall of the housing 3 and the high-pressure exhaust chamber 6. The countercurrent noise reduction cavities 10 are directly communicated with the high-pressure exhaust chamber 6, and the countercurrent noise reduction cavities 10 communicate with the high-pressure exhaust end 32 through the high-pressure exhaust chamber 6. On the side wall of each countercurrent noise reduction cavity 10 close to the working chamber 5, a countercurrent noise reduction hole 11 is provided. The countercurrent noise reduction holes 11 respectively communicate the countercurrent noise reduction cavities 10 with the working chamber 5.

[0062] Refer to Figure 5 and Figure 7 , the outer arc surface of the first driving blade peak 711 is set as the arc surface ab, the radian angle of the arc surface ab is γ, the width of the countercurrent noise reduction hole 11 is d, the radius of the outer edges of the blade peaks of the driving impeller 7 and the driven impeller 8 is R, the edge of the inner wall of the working chamber 5 at the low-pressure intake port 51 is set as A, the center line of the opening position of the countercurrent noise reduction hole 11 is set as B, the edge of the inner wall of the working chamber 5 at the high-pressure exhaust port 52 is set as C, the radian included angle between A and B is α, α = (2π) / n - γ / 2, n is the number of impeller heads, and d ≤ γR.

[0063] The implementation principle of Embodiment 1 is: As Figure 7As shown, start the Roots pump. The driving impeller 7 drives the driven impeller 8 to rotate synchronously through the synchronous gear. When the b side of the outer edge arc surface ab of the first driving lobe peak 711 just rotates to position A, the center of the outer edge arc surface ab of the second driving lobe peak 721 just rotates to position B. At this time, the first driving lobe 71, the second driving lobe 72, the wall plate 4 and the inner wall of the working chamber 5 jointly form the elementary volume 9. Since the width d of the countercurrent noise reduction hole 11 ≤ γR and the arc length of the outer edge arc surface ab of the second driving lobe peak 721 is greater than or equal to the width d of the countercurrent noise reduction hole, the outer edge arc surface ab of the second driving lobe peak 721 just blocks the countercurrent noise reduction hole 11 at this time, so that the high-pressure gas in the high-pressure exhaust chamber 6 cannot flow back into the elementary volume 9. At this time, the air pressure in the elementary volume 9 is close to or equal to the air pressure of the low-pressure air inlet 51; as the driving impeller 7 and the driven impeller 8 continue to rotate, the outer edge arc surface ab of the second driving lobe peak 721 evenly sweeps across the countercurrent noise reduction hole 11 and makes the countercurrent noise reduction hole 11 connect the countercurrent noise reduction cavity 10 and the elementary volume 9 respectively. At this time, the high-temperature and high-pressure gas entering the countercurrent noise reduction cavity 10 from the high-pressure exhaust chamber 6 is gradually pressurized by countercurrent into the elementary volume 9 under the control of the area of the countercurrent noise reduction hole 11; as Figure 8 shown, when the a side of the outer edge arc surface ab of the second driving lobe peak 721 rotates to position C, the air pressure in the elementary volume 9 is close to or equal to the pressure in the high-pressure exhaust chamber 6 at this time, as Figure 9 shown. At the moment when the a side of the outer edge arc surface ab of the second driving lobe peak 721 turns away from point C, since the pressure in the elementary volume 9 is close to or equal to the pressure in the high-pressure exhaust chamber 6, the impact effect caused by the backflow of high-pressure gas is greatly reduced, achieving the effect of effectively reducing the noise of the Roots pump. At the same time, the damage to the driving impeller 7, the driven impeller 8 and the working chamber 5 caused by the backflow impact of high-pressure gas is also reduced, improving the running stability and service life of the Roots pump.

[0064] Embodiment 2

[0065] A countercurrent noise reduction Roots pump. Referring to Figure 10 this figure, the difference between this embodiment and Embodiment 1 is that there is only 1 high-pressure exhaust end 32 outside the high-pressure exhaust port 52.

[0066] The implementation principle of Embodiment 2 refers to the implementation principle of Embodiment 1.

[0067] Embodiment 3

[0068] A countercurrent noise reduction Roots pump. Referring to Figure 11The difference between this embodiment and embodiment 1 is that a blocking cavity 13 connected to the inside of the countercurrent noise reduction cavity 10 is respectively provided on the outside of the countercurrent noise reduction cavity 10, and a processing window 131 is provided inside the blocking cavity 13 for facilitating the cutting of the countercurrent noise reduction hole 11. After the processing of the countercurrent noise reduction hole 11 is completed, the processing window 131 is sealed by a plug. In this embodiment, the countercurrent noise reduction hole 11 is an integral long hole.

[0069] The implementation principle of Example 3 refers to the implementation principle of Example 1.

[0070] Example 4

[0071] A countercurrent noise reduction Roots pump, refer to Figure 12 The difference between this embodiment and embodiment 1 is that a plurality of plugging cavities 13 are arranged at intervals on the outer wall of each countercurrent noise reduction cavity 10, each plugging cavity 13 is respectively connected to the inside of the countercurrent noise reduction cavity 10, and each plugging cavity 13 is provided with a processing window 131 for facilitating the cutting of the countercurrent noise reduction hole 11. After the processing of the countercurrent noise reduction hole 11 is completed, the processing window 131 is sealed by a plug. In this embodiment, the countercurrent noise reduction hole 11 is set as a circular hole, and the total area of ​​all the circular hole-shaped countercurrent noise reduction holes 11 arranged at intervals on each side is set according to the laws of fluid mechanics and thermodynamics.

[0072] The implementation principle of Example 4 refers to the implementation principle of Example 1.

[0073] Example 5

[0074] A countercurrent noise reduction Roots pump, refer to Figure 13 The difference between this embodiment and embodiment 1 is that the countercurrent noise reduction cavity 10 is fixedly connected to the outer wall of the housing 3, and the countercurrent noise reduction cavity 10 is separated from the high-pressure exhaust cavity 6. An external connection end 12 is provided at the outer end of the countercurrent noise reduction cavity 10. The external connection end 12 is connected to an external countercurrent boost gas source. The external countercurrent boost gas source can be drawn from the high-temperature and high-pressure gas of the high-pressure exhaust cavity 6, which is cooled by a cooling device to form a low-temperature and high-pressure gas or an external atmospheric gas source. There is only one high-pressure exhaust end 32 outside the high-pressure exhaust port 52.

[0075] The implementation principle of Embodiment 5 is as follows: When the outer arc surface ab of the second active blade peak 721 evenly sweeps across the countercurrent noise reduction holes 11 and causes the countercurrent noise reduction holes 11 to connect the countercurrent noise reduction cavity 10 with the basic volume 9 respectively, an external countercurrent pressurizing gas source connected to the external connection end 12 delivers gas to the countercurrent noise reduction cavity 10, and gradually countercurrent pressurizes into the basic volume 9 under the control of the opening area of the countercurrent noise reduction holes 11. When the a side of the outer edge arc surface ab of the second active blade peak 721 rotates to point C, the air pressure in the basic volume 9 is close to or equal to the pressure in the high-pressure exhaust cavity 6 at this time, so that the impact effect caused by the backflow of the high-pressure gas in the high-pressure exhaust cavity 6 into the basic volume 9 can be effectively reduced, achieving the effect of significantly reducing the noise of the Roots pump; The external countercurrent pressurizing gas source can be high-temperature and high-pressure gas led out from the high-pressure exhaust cavity 6. The temperature of the low-temperature and high-pressure gas source formed by cooling the high-temperature and high-pressure gas led out from the high-pressure exhaust cavity 6 by a cooling device is significantly lower than the temperature of the compressed gas in the high-pressure exhaust cavity. Therefore, using the low-temperature and high-pressure gas source with reduced temperature by cooling to countercurrent pressurize into the basic volume 9 can not only effectively weaken the impact effect caused by the backflow of the high-pressure gas in the high-pressure exhaust cavity 6 into the basic volume 9 to reduce the noise of the Roots pump, but also effectively reduce the working temperature of the Roots pump; When the Roots pump is used as a Roots pump discharging directly to the atmosphere, using the atmospheric gas source to countercurrent pressurize into the basic volume 9, also because the temperature of the atmospheric gas source is significantly lower than the temperature of the compressed gas in the high-pressure exhaust cavity 6, it can effectively reduce the working temperature of the Roots pump while reducing the noise of the Roots pump.

[0076] Embodiment 6

[0077] A countercurrent noise reduction Roots pump, referring to Figure 14 , the difference between this embodiment and Embodiment 5 is that 2 high-pressure exhaust ends 32 are symmetrically arranged outside the high-pressure exhaust port 52.

[0078] The implementation principle of Embodiment 6 refers to the implementation principle of Embodiment 5.

[0079] Embodiment 7

[0080] A countercurrent noise reduction Roots pump, referring to Figure 15 , the difference between this embodiment and Embodiment 1 is that the countercurrent noise reduction cavity 10 is arranged in the wall panel 4, the countercurrent noise reduction cavity 10 is directly connected to the high-pressure exhaust cavity 6 of the housing 3, the countercurrent noise reduction cavity 10 communicates with the high-pressure exhaust end 32 through the high-pressure exhaust cavity 6. In this embodiment, there are two symmetrically arranged high-pressure exhaust ends 32, and a pair of countercurrent noise reduction holes 11 communicating with the working cavity 5 are symmetrically opened on the side wall of the countercurrent noise reduction cavity 10 in the wall panel 4 facing the working cavity 5 direction.

[0081] The implementation principle of Embodiment 7 is as follows: As Figure 16As shown, when the first active blade peak 711 rotates to the edge A of the low-pressure air inlet 51, the end surface of the second active blade 72 just covers the corresponding counterflow noise reduction hole 11, and the elementary volume 9 is formed at this time. The impeller continues to rotate, as shown in FIG. Figure 17 As shown, the end surface of the second active blade 72 begins to turn away from the corresponding countercurrent noise reduction hole 11, and the countercurrent noise reduction hole 11 gradually opens. The high-pressure gas in the countercurrent noise reduction cavity 10 is controlled by the area of ​​the countercurrent noise reduction hole 11 and gradually countercurrently pressurizes the unit volume 9; Figure 18 As shown, when the second active blade peak 721 rotates to the edge C of the inner wall of the working chamber 5, the gas pressure in the elementary volume 9 is close to or equal to the pressure in the high-pressure exhaust chamber 6. At the moment when the second active blade peak 721 rotates away from C, the pressure in the elementary volume 9 is close to or equal to the pressure in the high-pressure exhaust chamber 6, thereby significantly reducing the impact effect caused by the backflow of high-pressure gas, thereby effectively reducing the noise of the Roots pump.

[0082] Example 8

[0083] A countercurrent noise reduction Roots pump, refer to Figure 19 The difference between this embodiment and embodiment 7 is that the countercurrent noise reduction cavity 10 is arranged in the wall panel 4, and the countercurrent noise reduction cavity 10 is separated from the high-pressure exhaust cavity 6. A pair of external connection ends 12 respectively connected to the countercurrent noise reduction cavity 10 are symmetrically arranged on both sides of the wall panel 4. The external connection ends 12 are connected to an external countercurrent pressurized air source. The external countercurrent pressurized air source can be a low-temperature high-pressure gas formed by cooling the high-temperature and high-pressure gas drawn from the high-pressure exhaust cavity 6 through a cooling device, or an external atmospheric gas source.

[0084] The implementation principle of Example 8 is as follows: when the end face of the second active blade 72 evenly sweeps over the countercurrent noise reduction hole 11, the countercurrent noise reduction hole 11 respectively connects the countercurrent noise reduction cavity 10 arranged on the wall panel 4 with the elementary volume 9. At this time, the external countercurrent pressurized air source connected to the external connection end 12 transports gas to the countercurrent noise reduction cavity 10, and gradually countercurrently pressurizes the gas into the elementary volume 9 under the control of the opening area of ​​the countercurrent noise reduction hole 11. At the moment when the second active blade peak 721 turns away from point C, since the pressure in the elementary volume 9 is close to or equal to the pressure in the high-pressure exhaust chamber 6, the impact effect caused by the reflux of the high-pressure gas in the high-pressure exhaust chamber 6 to the elementary volume 9 can be effectively reduced, thereby achieving the effect of significantly reducing the noise of the Roots pump.

[0085] Since the temperature of the low-temperature and high-pressure gas source formed by cooling the high-temperature and high-pressure gas led out from the high-pressure exhaust cavity 6 by the cooling device is significantly lower than the temperature of the compressed gas in the high-pressure exhaust cavity 6, therefore, using the cooled low-temperature gas source to reverse flow and boost the pressure into the basic volume 9 can not only effectively weaken the impact effect caused by the reverse flow of the high-pressure gas in the high-pressure exhaust cavity 6 into the basic volume 9 to reduce the noise of the roots pump, but also effectively reduce the working temperature of the roots pump; when the roots pump is used as a roots pump directly exhausting to the atmosphere, using the atmospheric gas source to reverse flow and boost the pressure into the basic volume 9, also because the temperature of the atmospheric gas source is significantly lower than the temperature of the compressed gas in the high-pressure exhaust cavity 6, it can also effectively reduce the working temperature of the roots pump while reducing the noise of the roots pump. Therefore, this embodiment can also effectively reduce the noise of the roots pump and play a role in reducing the working temperature of the roots pump.

[0086] The above are all the preferred embodiments of this application, and the protection scope of this application is not limited thereby. Therefore, all equivalent changes made according to the structure, shape, and principle of this application should be covered within the protection scope of this application.

Claims

1. A countercurrent noise reduction Roots pump, comprising a housing (3) and a working chamber (5) arranged inside the housing (3). The active impeller (7) and the driven impeller (8) are symmetrically arranged in conjugate in the working chamber (5). At both axial ends of the active impeller (7) and the driven impeller (8), there is a wall plate (4) fixedly connected to the housing (3). One side of the housing (3) is provided with a low-pressure air inlet end (31), and the other side of the housing (3) is provided with a high-pressure exhaust end (32). A low-pressure air inlet (51) is opened on the side of the working chamber (5) close to the low-pressure air inlet end (31), and a high-pressure exhaust port (52) is opened on the side of the working chamber (5) far from the low-pressure air inlet (51). A high-pressure exhaust chamber (6) is arranged outside the high-pressure exhaust port (52). It is characterized in that: A pair of countercurrent noise reduction cavities (10) are symmetrically arranged inside the housing (3) on the outside of the working chamber. On the side wall of each countercurrent noise reduction cavity (10) close to the working chamber (5), countercurrent noise reduction holes (11) are symmetrically opened. The countercurrent noise reduction holes (11) are designed according to the principles of fluid mechanics and thermodynamics, and the countercurrent noise reduction holes (11) communicate with the countercurrent noise reduction cavity (10) and the working chamber (5) respectively; the outer arc surfaces of the blade peaks of the active impeller (7) and the driven impeller (8) are arranged close to the inner edge of the working chamber (5); the outer arc surface of the blade peak is set as arc ab, and the radian angle corresponding to the arc ab is γ. The width of the countercurrent noise reduction hole (11) is d, the outer radius of the blade peaks of the active impeller (7) and the driven impeller (8) is R, the edge of the inner wall of the working chamber (5) at the low-pressure air inlet (51) is set as A, the center line of the opening position of the countercurrent noise reduction hole (11) is set as B, and the edge of the inner wall of the working chamber (5) at the high-pressure exhaust port (52) is set as C. The radian angle between A and B is α, and α = (2π) / n – γ / 2, where n is the number of impeller heads, and d ≤ γR; when the b side of the outer arc surface of the first blade peak just rotates to the intake end edge A of the inner wall of the working chamber (5) at the low-pressure air inlet (51), the center of the outer arc surface ab of the second blade peak adjacent to the first blade peak just rotates to the center line B of the opening position of the countercurrent noise reduction hole (11) on the inner wall of the working chamber (5). The first blade peak, the second blade peak, the wall plate (4) and the inner wall of the working chamber (5) together form a basic volume (9). Since the width d of the countercurrent noise reduction hole (11) ≤ γR, the arc length of the arc ab is greater than or equal to the width d of the countercurrent noise reduction hole (11), and the outer arc surface ab of the second blade peak just blocks the countercurrent noise reduction hole (11); at the moment when the a side of the outer arc surface ab of the second blade peak turns away from C, the pressure in the basic volume (9) is close to or equal to the pressure in the high-pressure exhaust chamber (6).

2. A countercurrent noise reduction Roots pump according to claim 1, It is characterized in that: The counterflow noise reduction cavity (10) is arranged on the outer wall of the casing (3) and is directly connected to the high-pressure exhaust cavity (6); the counterflow noise reduction cavity (10) is connected to the high-pressure exhaust end (32) through the high-pressure exhaust cavity (6).

3. A countercurrent noise reduction Roots pump according to claim 1, Features: The countercurrent noise reduction cavity (10) is arranged on the outer wall of the casing (3) and is separated from the high-pressure exhaust cavity (6); an external connection end (12) is arranged at one end of the countercurrent noise reduction cavity (10) away from the countercurrent noise reduction hole (11); and the external connection end (12) is connected to an external countercurrent pressurized air source.

4. A countercurrent noise reduction Roots pump according to claim 3, Features: The external countercurrent pressurized gas source is a low-temperature high-pressure gas formed by cooling the high-temperature high-pressure gas drawn from the high-pressure exhaust chamber (6) through a cooling device, or an external atmospheric gas source with a relatively low temperature.

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