A low pressure difference air filter device

Abstract

The present invention provides a low-pressure difference air filtering device, which controls the distance from the outer wall of the second inlet flow channel to the gas inlet to be smaller than the distance from the outer wall of the second inlet flow channel to the gas outlet, increases the gap between the filter unit and the inner wall of the lower cylinder body to connect the gas outlet to form an outlet chamber, and reduces the pressure loss of the compressed gas due to space contraction before the gas outlet; the centers of the horizontal projections of the first gas injection section and the second gas injection section on the top plane of the end cover substrate do not overlap, so that there is a certain stroke of guiding buffer for the high-pressure and high-flow rate compressed air when passing through the second gas injection pipe; a limiting platform is provided in the second inlet flow channel, and the inner wall surface of the second inlet flow channel is divided into an upper inner wall surface and a lower inner wall surface from top to bottom, and the upper inner wall surface smoothly transitions with the inner wall surface of the first gas injection pipe, so that the high-pressure and high-flow rate compressed air can flow smoothly into the inner wall surface of the first gas injection pipe; the first gas injection section is set to an elliptical shape, and the second gas injection section is circular, so as to reduce the pressure difference.

Description

Technical Field

[0001] The invention belongs to the technical field of compressed air filtration, and in particular relates to a low pressure difference air filtration device. Background Art

[0002] Compressed air has become the second largest energy source in modern industry besides electricity. In the modern industrial field, it runs through the entire production process. Compressed air filters, as filtering equipment for compressed air filtration, are one of the basic auxiliary equipment in industrial production.

[0003] In the actual production process, for the actual use effect, the requirements for the air pressure and air flow speed of compressed air are getting higher and higher. The compressed air is required to have a higher pressure and speed at the outlet, which causes the compressed air to maintain a high flow rate and large flow in the compressed air filter. Therefore, the requirements for the air resistance formed by the compressed air filter during the gas flow process are increased, and the pressure difference between the inlet and outlet of the gas should not be too large. Otherwise, the disadvantage of large pressure loss can only be compensated by increasing the power output of the power air pump.

[0004] In a traditional compressed air filter, it usually includes an upper shell, a lower shell and a filter element. The compressed air is injected from the air inlet of the upper shell, and the gas is injected into the center of the filter element. The air intake pipe in the upper shell is designed to be centered inside the upper shell, resulting in compression of the space in the outlet chamber. After the high-speed and high-pressure compressed air is injected into the filter element through the air intake pipe, it must pass through a smaller outlet chamber before being discharged from the air outlet. This flow channel design has large air resistance, large pressure loss, and large front-to-back pressure difference, which is not conducive to the flow of compressed air and continues to be a low-pressure difference air filtration device. Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide a low-pressure difference air filter device, which solves the problems of large resistance and large pressure difference in the compressed air filter in the prior art when processing high-pressure and high-flow rate compressed air, optimizes the overall flow channel design of high-pressure and high-flow rate compressed air in the air filter device, reduces pressure loss, reduces the front and rear pressure difference, reduces production costs, and saves energy.

[0006] In order to achieve the above-mentioned purpose, the present invention provides a low-pressure difference air filtering device, including an upper cylinder body, a lower cylinder body and a filter unit, the upper cylinder body is provided with a gas inlet flow channel for air intake and a gas outlet for air outlet, the upper cylinder body is detachably connected to the lower cylinder body, the filter unit is detachably fixed to the bottom of the upper cylinder body, the filter unit is gap-matched with the inner wall of the lower cylinder body, the gap space between the filter unit and the inner wall of the lower cylinder body together with the space surrounded by the upper cylinder body downward constitutes an air outlet chamber, the filter unit includes an upper end cover, a filter element and a lower end cover, the filter element is arranged at the upper end The upper end cover comprises a first gas injection pipe, a second gas injection pipe and an end cover substrate, the gas inlet channel comprises a first inlet channel and a second inlet channel, the first inlet channel and the second inlet channel are both hollow in the center, the first inlet channel comprises a gas inlet, the gas inlet is used to connect the gas inlet, the second inlet channel is matched and connected with the first gas injection pipe, the inner wall shape of the second inlet channel is defined by the outer wall shape of the first gas injection pipe, and the distance from the outer wall of the second inlet channel to the gas inlet is smaller than the distance from the outer wall of the second inlet channel to the gas outlet;

[0007] The first gas injection pipe and the end cover substrate are connected via a second gas injection pipe, the first gas injection pipe is hollow in the center, the second gas injection pipe is hollow in the center, the first gas injection pipe is provided with a first opening at the top end, the first gas injection pipe is provided with a second opening at the bottom end, the second gas injection pipe is provided with a third opening at the top end, the second gas injection pipe is provided with a fourth opening at the bottom end, and the end cover substrate is provided with a fifth opening at the top end;

[0008] The inner contour of the fourth opening of the second gas injection pipe is consistent with the inner contour of the fifth opening on the top of the end cover substrate, the inner contour of the third opening of the second gas injection pipe is consistent with the inner contour of the second opening of the first gas injection pipe, and the second gas injection pipe realizes a smooth transition between the second opening of the first gas injection pipe and the fifth opening of the end cover substrate;

[0009] The connecting cross section enclosed by the inner contour lines at the connection between the first gas injection tube and the second gas injection tube is the first gas injection cross section, and the connecting cross section enclosed by the inner contour lines at the connection between the second gas injection tube and the end cover substrate is the second gas injection cross section. The first gas injection cross section is a quasi-circular shape, and the second gas injection cross section is a circular shape. The center of the horizontal projection of the first gas injection cross section on the top plane of the end cover substrate is the first projection center point, and the center of the horizontal projection of the second gas injection cross section on the top plane of the end cover substrate is the second projection center point. The first projection center point and the second projection center point do not coincide with each other, and the first projection center point is located in the offset direction of the second projection center point extending along the center dividing line direction of the second gas injection cross section.

[0010] Furthermore, a limiting platform is provided in the second inlet channel, and the limiting platform divides the inner wall surface of the second inlet channel into an upper inner wall surface and a lower inner wall surface from top to bottom. The upper plane of the first air injection pipe abuts against the limiting platform, and the inner contour of the connection between the upper inner wall surface and the inner wall surface of the first air injection pipe is defined by the shape of the inner wall surface of the first air injection pipe, and the inner contour of the lower inner wall surface is defined by the shape of the outer wall of the first air injection pipe.

[0011] Furthermore, the first gas injection pipe is an elliptical cylinder structure with a hollow center, the first gas injection section is an elliptical shape, and the connecting line between the two foci of the first gas injection section is perpendicular to the connecting line between the first projection center point and the second projection center point.

[0012] Further, the major axis length of the first gas injection cross section is greater than or equal to the diameter length of the second gas injection cross section, and the minor axis length of the first gas injection cross section is less than or equal to the diameter of the second gas injection cross section.

[0013] Furthermore, the area of ​​the first gas injection cross section is less than or equal to the area of ​​the second gas injection cross section.

[0014] Furthermore, a projection of the inner wall surface of the first inlet channel on the gas inlet plane is a first air inlet section, a horizontal projection of the inner wall surface of the second inlet channel on the top plane of the end cover substrate is a second air inlet section, and an area of ​​the second air inlet section is greater than or equal to an area of ​​the first air inlet section.

[0015] Furthermore, the air outlet chamber includes an upper air outlet chamber and a lower air outlet chamber, the upper air outlet chamber includes a first upper air outlet chamber and a second upper air outlet chamber, the first upper air outlet chamber is formed by the outer wall surface of the second inlet channel close to the gas inlet, the inner wall surface of the upper cylinder body between the outer wall surface of the second inlet channel and the gas inlet, the second upper air outlet chamber is formed by the outer wall surface of the second inlet channel close to the gas outlet, the inner wall surface of the upper cylinder body between the outer wall surface of the second inlet channel and the gas outlet, and the space surrounded by the gas outlet, and the lower air outlet chamber is formed by the outer surface of the filter unit and the space surrounded by the inner surface of the lower cylinder body The boundary line between the upper air outlet chamber and the lower air outlet chamber is a horizontal plane surrounded by the upper edge of the lower cylinder body, and the boundary line between the first upper air outlet chamber and the second upper air outlet chamber is a vertical plane perpendicular to the first air injection section and coincident with the long axis of the first air injection section. Two symmetrical curved surfaces are provided on the inner wall surface of the upper cylinder body in the second upper air outlet chamber, and the curved surfaces are bent toward the second upper air outlet chamber, and the curved surfaces include a vertical section and an inclined section, and the vertical section and the inclined section have a smooth transition, and a fillet is formed at the connection between the vertical section and the inclined section, and the fillet protrudes out of the second upper air outlet chamber.

[0016] Furthermore, the inner contour line of the fourth opening at the bottom end of the second air injection tube is a circular shape, the inner contour line of the third opening at the top end of the second air injection tube is an elliptical shape, the semi-elliptical arc line of the third opening of the second air injection tube along the offset direction is a first semi-elliptical arc line, the semi-elliptical arc line of the third opening of the second air injection tube along the direction opposite to the offset direction is a second semi-elliptical arc line, the semi-circular arc line of the fourth opening of the second air injection tube along the offset direction is a first semi-circular arc line, the semi-circular arc line of the fourth opening of the second air injection tube along the direction opposite to the offset direction is a second semi-circular arc line, the curved surface enclosed by the first semi-elliptical arc line and the first semi-circular arc line is a semi-funnel shape that gradually shrinks from top to bottom, and the curved surface enclosed by the second semi-elliptical arc line and the second semi-circular arc line is a diffusion shape that gradually diverges from top to bottom.

[0017] Furthermore, the angle between the pipeline center lines of the first inlet flow channel and the second inlet flow channel is an obtuse angle.

[0018] Furthermore, at least two convex rings are arranged on the outer surface of the first gas injection pipe, the outer edges of the convex rings are elliptical, and a groove is formed between every two convex rings, and the groove is used to place a sealing rubber ring.

[0019] Beneficial effects of the present invention:

[0020] 1. The present invention provides a low-pressure difference air filter device, which controls the distance from the outer wall of the second inlet flow channel to the gas inlet to be smaller than the distance from the outer wall of the second inlet flow channel to the gas outlet, increases the gap between the filter unit and the inner wall of the lower cylinder body to connect the gas outlet to form the gas outlet chamber, reduces the pressure loss of the compressed gas due to space contraction before the gas outlet, and the centers of the horizontal projections of the first gas injection section and the second gas injection section on the top plane of the end cover substrate do not overlap, so that the high-pressure and high-flow rate compressed air has a certain stroke of guide buffer when passing through the second gas injection pipe, and is injected into the filter element in the direction opposite to the offset direction, forming an overall low-pressure difference flow channel in the air filter device, reducing pressure loss, saving energy input in production, and reducing production costs;

[0021] 2. A limiting platform is provided in the second inlet flow channel, and the inner wall surface of the second inlet flow channel is divided into an upper inner wall surface and a lower inner wall surface from top to bottom. The upper inner wall surface smoothly transitions with the inner wall surface of the first air injection pipe, so that the high-pressure and high-flow rate compressed air can smoothly flow into the inner wall surface of the first air injection pipe, and the first air injection cross section is set to an elliptical shape, and the second air injection cross section is a circular shape. The long axis length of the ellipse is greater than or equal to the diameter length of the circle, and the short axis length of the ellipse is less than or equal to the diameter length of the circle. In addition, the curved surface enclosed by the first semi-elliptical arc line and the first semi-circular arc line is a semi-funnel shape that gradually shrinks from top to bottom, and the curved surface enclosed by the second semi-elliptical arc line and the second semi-circular arc line is a diffusion shape that gradually diverges from top to bottom, so that a smooth transition from an elliptical shape to a circular cross section is achieved in the structure, and the high-pressure and high-flow rate air is buffered in the diffusion area to reduce the impact, and the semi-funnel contraction area realizes the collection and guidance of the air;

[0022] 3. The air outlet chamber includes an upper air outlet chamber and a lower air outlet chamber, and the upper air outlet chamber includes a first upper air outlet chamber and a second upper air outlet chamber. The compressed air processed by the filter unit flows into the lower air outlet chamber, and then enters the upper air outlet chamber from the lower air outlet chamber, and is finally discharged from the gas outlet. Since the second upper air outlet chamber is directly connected to the gas outlet, two symmetrical curved surfaces are arranged on the upper cylinder wall surface in the second upper air outlet chamber, and the curved surfaces are bent inside the second upper air outlet chamber. Under the guidance of this curved surface, the compressed air coming up from the lower air outlet chamber is first processed from bottom to top, and finally the compressed air is discharged from the gas outlet in the horizontal direction. This flow channel arrangement has a small gas pressure loss and plays a good role in guiding the airflow. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The present invention is further described using the accompanying drawings, but the embodiments in the accompanying drawings do not constitute any limitation to the present invention. A person skilled in the art can obtain other drawings based on the following drawings without creative work.

[0024] Figure 1 It is a schematic diagram of the overall structure of a low pressure difference air filtering device provided by the present invention.

[0025] Figure 2 It is a front view of a low pressure difference air filtering device provided by the present invention.

[0026] Figure 3 is Figure 2 Sectional view along tangent line BB.

[0027] Figure 4 The present invention is a schematic diagram of the overall structure of an upper cylinder body and a filter unit in a low-pressure difference air filter device provided by the present invention in an assembled state.

[0028] Figure 5It is a top view of a low pressure difference air filtering device provided by the present invention.

[0029] Figure 6 is Figure 5 Section view along tangent line AA.

[0030] Figure 7 The invention discloses a half-section view of an upper cylinder body and an upper end cover in an assembled state in a low-pressure difference air filtering device provided by the present invention.

[0031] Figure 8 It is a schematic diagram of the overall structure of the upper end cover provided by the present invention.

[0032] Fig. 9 It is a front view of the upper end cover provided by the present invention.

[0033] Fig.10 It is a top view of the upper end cover provided by the present invention.

[0034] Fig.11 is Fig.10 Sectional view along the tangent line CC. DETAILED DESCRIPTION

[0035] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0037] Embodiment 1:

[0038] Reference Figures 1 to 6The present embodiment provides a low pressure difference air filtering device, comprising an upper cylinder body 1, a lower cylinder body 2 and a filter unit 3, the upper cylinder body 1 is provided with a gas inlet flow channel for air intake and a gas outlet 14 for air outlet, the upper cylinder body 1 and the lower cylinder body 2 are threadedly connected, the outer thread on the upper part of the lower cylinder body 2 is screwed into the inner thread of the upper cylinder body 1 from bottom to top, the upper cylinder body 1 and the lower cylinder body 2 are detachably connected, the filter unit 3 is detachably fixed to the bottom of the upper cylinder body 1, the filter unit 3 is fixed to the bottom of the upper cylinder body 1 by snap-fitting, the filter unit 3 is gap-matched with the inner wall of the lower cylinder body 2, the gap space between the filter unit 3 and the inner wall of the lower cylinder body 2 together with the space surrounded by the upper cylinder body 1 downward constitutes an air outlet chamber, the air processed by the filter unit 3 enters the air outlet chamber, and is discharged from the gas outlet 14.

[0039] Reference Figures 7 to 11 In this embodiment, the filter unit 3 includes an upper end cover 31, a filter element 32 and a lower end cover 33. The filter element 32 is arranged between the upper end cover 31 and the lower end cover 33. The upper end cover 31 includes a first gas injection pipe 34, a second gas injection pipe 35 and an end cover substrate 36. The gas inlet channel includes a first inlet channel 11 and a second inlet channel 12. The first inlet channel 11 and the second inlet channel 12 are both hollow in the center. The first inlet channel 11 includes a gas inlet 13. The gas inlet 13 is used to connect the intake. The second inlet channel 12 is matched with the first gas injection pipe 34. The external high-pressure and high-flow rate compressed air enters from the gas inlet 13 and passes through the first inlet channel 11, The second inlet flow channel 12, the first gas injection pipe 34 and the second gas injection pipe 35, then enter the filter element 32 for filtering treatment, the inner wall shape of the second inlet flow channel 12 is defined by the outer wall shape of the first gas injection pipe 34, the first gas injection pipe 34 can be directly inserted into the inner wall of the second inlet flow channel 12 and fixed, the distance from the outer wall of the second inlet flow channel 12 to the gas inlet 13 is smaller than the distance from the outer wall of the second inlet flow channel 12 to the gas outlet 14, so as to control the position of the second inlet flow channel 12 in the upper cylinder body 1 in a top-down view state to deviate from the center and lean towards the gas inlet 13 to increase the distance from the outer wall of the second inlet flow channel 12 to the gas outlet 14;

[0040] The first gas injection pipe 34 and the end cover substrate 36 are connected via the second gas injection pipe 35. The center of the first gas injection pipe 34 is hollow, and the center of the second gas injection pipe 35 is hollow. The top of the first gas injection pipe 34 is provided with a first opening 10, and the bottom of the first gas injection pipe 34 is provided with a second opening 20. The top of the second gas injection pipe 35 is provided with a third opening 30, and the bottom of the second gas injection pipe 35 is provided with a fourth opening 40. The top of the end cover substrate 36 is provided with a fifth opening 50. High-pressure and high-flow-rate air is injected from the gas inlet 13 of the upper cylinder body 1, and deflects at a certain angle in the first inlet flow channel 11 and the second inlet flow channel 12, from the horizontal direction to the downward direction, and then enters the air intake mechanism through the fifth opening 50, passes through the first opening 10, the second opening 20, the third opening 30 and the fourth opening 40 in sequence, and is finally blown out from the bottom of the end cover;

[0041] In addition, the first gas injection pipe 34, the second gas injection pipe 35 and the end cover substrate 36 are integrally formed by injection molding, the inner contour of the fourth opening 40 of the second gas injection pipe 35 is consistent with the inner contour of the fifth opening 50 at the top of the end cover substrate 36, the inner contour of the third opening 30 of the second gas injection pipe 35 is consistent with the inner contour of the second opening 20 of the first gas injection pipe 34, and the second gas injection pipe 35 realizes a smooth transition between the second opening 20 of the first gas injection pipe 34 and the fifth opening 50 of the end cover substrate 36;

[0042] Reference Fig.11 More specifically, the connecting cross section enclosed by the inner contour lines at the connection between the first gas injection tube 34 and the second gas injection tube 35 is the first gas injection cross section, and the connecting cross section enclosed by the inner contour lines at the connection between the second gas injection tube 35 and the end cover substrate 36 is the second gas injection cross section. In a top view, with the top plane of the end cover substrate 36 as the projection plane, the first gas injection cross section is a quasi-circular shape, and the second gas injection cross section is a circular shape. The center of the horizontal projection of the first gas injection cross section on the top plane of the end cover substrate 36 is the first projection center point, and the center of the horizontal projection of the second gas injection cross section on the top plane of the end cover substrate 36 is the second projection center point. The first projection center point and the second projection center point do not overlap, and the first projection center point is located in the offset direction of the second projection center point extending along the central dividing line direction of the second gas injection cross section, such as Fig.10 As shown, the offset direction of the second projection center point extending along the center dividing line of the second air intake section is to the left of the second projection center point, and the first projection center point is located to the left of the second projection center point.

[0043] Reference Figure 7In this embodiment, a limiting platform 15 is provided in the second inlet flow channel 12, and the limiting platform 15 divides the inner wall surface of the second inlet flow channel 12 from top to bottom into an upper inner wall surface 16 and a lower inner wall surface 17, wherein the wall thickness of the upper inner wall surface 16 is thicker, and the wall thickness of the lower inner wall surface 17 is thinner. Due to this difference in thickness, a limiting platform 15 is formed at the interface between the upper inner wall surface 16 and the lower inner wall surface 17, and the upper plane of the first gas injection pipe 34 abuts against the limiting platform 15, which is also convenient when the filter unit 3 is inserted into the upper cylinder body 1, that is, when the first gas injection pipe 34 is inserted into the second inlet flow channel 12, there is a limiting signal, when the upper plane of the first gas injection tube 34 abuts against the limit platform 15, it proves that it has been inserted and matched in place. When it is matched in place, the inner contour of the connection between the upper inner wall surface 16 and the inner wall surface of the first gas injection tube 34 is limited by the shape of the inner wall surface of the first gas injection tube 34, and the inner contour of the lower inner wall surface 17 is limited by the shape of the outer wall of the first gas injection tube 34. That is, for the air flow channel, there is a smooth transition from the upper inner wall surface 16 to the inner wall surface of the first gas injection tube 34. In addition, the lower inner wall surface 17 is sealed and connected to the outer wall of the first gas injection tube 34 to prevent gas leakage without being processed by the filter element 32.

[0044] In this embodiment, the first gas injection tube 34 is an elliptical cylinder structure with a hollow center, and the first gas injection cross-section is an elliptical shape. The connecting line between the first projection center point and the second projection center point is defined as the first connecting line, and the connecting line between the two foci of the first gas injection cross-section is defined as the second connecting line, that is, the straight line where the major axis of the first gas injection cross-section ellipse lies coincides with the second connecting line, and the straight line where the minor axis of the first gas injection cross-section ellipse lies is defined as the third connecting line, wherein on the horizontal projection plane, the first connecting line is perpendicular to the second connecting line, and the first connecting line coincides with the third connecting line, and the first connecting line divides the second gas injection cross-section into two symmetrical patterns along its center, and the two foci of the first gas injection cross-section are separated on both sides of the first connecting line, and the two foci are symmetrical relative to the first connecting line, that is, each focus has the same vertical distance from the first connecting line.

[0045] The first gas injection cross section is an elliptical shape, and the inner wall surface of the first gas injection pipe 34 of the elliptical column structure is a smooth curved surface 5 without edges and corners. When the curved surface 5 passes through the second gas injection pipe 35 and transitions to the circular cross section of the fifth opening 50 of the end cover substrate 36, the air resistance along the way is small, the pressure loss is small, and the short axis of the ellipse set to the first gas injection cross section is set to be consistent with the offset direction, which is beneficial to the space allocation of the air inlet chamber and the air outlet chamber divided inside the upper cylinder body 1. If the long axis is set to be consistent with the offset direction, It will compress the space of the air outlet chamber. If the short axis is at a certain angle to the offset direction, the space of the air outlet chamber will be irregular. Therefore, the best implementation method is to set the short axis to be consistent with the offset direction to achieve maximum utilization of the air outlet chamber space; in addition, according to the characteristics of the elliptical shape, when the first air injection pipe 34 is inserted into the second inlet channel 12, when the upper cylinder body 1 and the filter unit 3 are fixed, relative rotation cannot occur between the first air injection pipe 34 and the second inlet channel 12, thereby further improving the assembly stability.

[0046] In this embodiment, the major axis length of the first gas injection section is greater than or equal to the diameter length of the second gas injection section, the minor axis length of the first gas injection section is less than or equal to the diameter of the second gas injection section, and the area of ​​the first gas injection section is less than or equal to the area of ​​the second gas injection section. In the process of flowing from top to bottom, the air is first narrow and then wide in the offset direction, and first wide and then narrow in the direction perpendicular to the offset direction. The direction of gradually widening in the offset direction is consistent with the flow direction of the air when it enters the upper cylinder body 1. In these two mutually perpendicular directions, the height of the second gas injection pipe 35 gradually changes from top to bottom, effectively guiding the air to be converged and rectified, reducing pressure loss and reducing pressure difference.

[0047] In this embodiment, the projection of the inner wall surface of the first inlet flow channel 11 on the plane of the gas inlet 13 is the first air intake section, and the horizontal projection of the inner wall surface of the second inlet flow channel 12 on the top plane of the end cover substrate 36 is the second air intake section. The area of ​​the second air intake section is greater than or equal to the area of ​​the first air intake section. The high-pressure and high-flow rate compressed air enters from the gas inlet 13, first passes through the first air intake section, and then flows into the second air intake section. In the second inlet flow channel 12, due to the increase in the cross-sectional area of ​​the gas flow, the flow rate of the air will decrease, and it enters the filter unit 3 at a relatively low speed, which can reduce the pressure loss generated when the gas enters the filter unit 3 and reduce the pressure difference.

[0048] Reference Figure 6As a preferred embodiment, the gas outlet chamber includes an upper gas outlet chamber and a lower gas outlet chamber 43, the upper gas outlet chamber includes a first upper gas outlet chamber 41 and a second upper gas outlet chamber 42, the first upper gas outlet chamber 41 is formed by the outer wall surface of the second inlet flow channel 12 close to the gas inlet 13, and the space enclosed by the inner wall surface of the upper cylinder body 1 between the outer wall surface of the second inlet flow channel 12 and the gas inlet 13, and the first inlet flow channel 11 is located above the first upper gas outlet chamber 41;

[0049] The second upper gas outlet chamber 42 is formed by the outer wall surface of the second inlet flow channel 12 close to the gas outlet 14, the inner wall surface of the upper cylinder body 1 between the outer wall surface of the second inlet flow channel 12 and the gas outlet 14, and the space surrounded by the gas outlet 14. The left side of the second upper gas outlet chamber 42 is the second inlet flow channel 12, and the right side is the gas outlet 14.

[0050] The lower air outlet chamber 43 is formed by the space enclosed by the outer surface of the filter unit 3 and the inner surface of the lower cylinder body 2;

[0051] The boundary between the upper air outlet chamber and the lower air outlet chamber 43 is a horizontal plane surrounded by the upper edge of the lower cylinder body 2. Below this horizontal plane is the lower air outlet chamber 43, and above this horizontal plane is the upper air outlet chamber; and in the upper air outlet chamber, the boundary between the first upper air outlet chamber 41 and the second upper air outlet chamber 42 is a vertical plane perpendicular to the first air injection section and coincident with the long axis of the first air injection section. Since the first air injection section is an elliptical shape, in a top view, the vertical plane containing the long axis is used as the boundary, and the chamber on the left is the first upper air outlet chamber 41, and the chamber on the right is the second upper air outlet chamber 42;

[0052] Wherein, based on the direction of the air inlet and outlet, the distance of the first upper air outlet chamber 41 in this direction is smaller than the distance of the second upper air outlet chamber 42 in this direction, so as to increase the volume of the second upper air outlet chamber 42 and improve the flow field;

[0053] Additionally, in the second upper air outlet chamber 42, as Figure 3As shown in the left sectional view, the inner wall surface of the upper cylinder body 1 in the second upper air outlet chamber 42 is provided with two symmetrical curved surfaces 5, the curved surface 5 is bent toward the second upper air outlet chamber 42, the curved surface 5 includes a vertical section 51 and an inclined section 52, the vertical section 51 and the inclined section 52 are smoothly transitioned, and the connection between the vertical section 51 and the inclined section 52 forms a fillet, and the fillet protrudes from the second upper air outlet chamber 42, so when the compressed air processed by the filter unit 3 flows to the lower air outlet chamber 43, and then enters the upper air outlet chamber from the lower air outlet chamber 43, the compressed air is finally During the process of being discharged from the gas outlet 14, since the second upper air outlet chamber 42 is directly connected to the gas outlet 14, two symmetrical curved surfaces 5 are set on the inner wall surface of the upper cylinder body 1 in the second upper air outlet chamber 42, and the curved surface 5 is bent toward the second upper air outlet chamber 42. Under the guidance of the curved surface 5, the compressed air coming up from the lower air outlet chamber 43 is first processed from bottom to top, and finally the compressed air is discharged from the gas outlet 14 in the horizontal direction. This flow channel arrangement has a small gas pressure loss and plays a good role in guiding the airflow.

[0054] In this embodiment, the upper end cover 31 of the filter unit 3 is a key component connecting the upper cylinder body 1 and the filter element 32. Its shape and structure are very important for the transition of air entering the filter element 32. The inner contour line of the fourth opening 40 at the bottom end of the second air injection pipe 35 is a circular shape, and the inner contour line of the third opening 30 at the top end of the second air injection pipe 35 is an elliptical shape. The semi-elliptical arc of the third opening 30 of the second air injection pipe 35 in the offset direction is the first semi-elliptical arc, and the semi-elliptical arc of the third opening 30 of the second air injection pipe 35 in the direction opposite to the offset direction is the second semi-elliptical arc. The semicircular arc line of the fourth opening 40 of the second gas injection pipe 35 along the offset direction is the first semicircular arc line, the semicircular arc line of the fourth opening 40 of the second gas injection pipe 35 along the direction opposite to the offset direction is the second semicircular arc line, the first semi-elliptical arc line is connected to the first semicircular arc line in correspondence, and the curved surface 5 enclosed by the first semi-elliptical arc line and the first semicircular arc line is a semi-funnel shape 6 that gradually shrinks from top to bottom, the second semi-elliptical arc line and the second semicircular arc line are connected to each other in correspondence, and the curved surface 5 enclosed by the second semi-elliptical arc line and the second semicircular arc line is a diffusion shape 7 that gradually diverges from top to bottom.

[0055] It should be noted that by dividing the second gas injection pipe 35 into two parts in space, the left half closer to the gas inlet 13 of the upper cylinder body 1 is semi-funnel-shaped 6, and the right half farther away from the gas inlet 13 of the upper cylinder body 1 is diffuser-shaped 7. From the perspective of the front view, the cross-section of the second gas injection pipe 35 is a quadrilateral, including an upper structural line, a lower structural line, a left structural line and a right structural line, wherein the upper structural line and the lower structural line are parallel to each other, the left structural line and the right structural line are both inclined to the right in the direction from top to bottom, and the acute angle between the left structural line and the upper structural line is larger than the acute angle between the right structural line and the upper structural line, so that the high-pressure and high-flow air can achieve a decrease in flow rate in the diffuser-shaped space 7, thereby achieving a buffering effect, and can guide the air to better flow into the filter element 32 below, thereby reducing pressure loss and impact.

[0056] As a preferred embodiment, the second air injection pipe 35 has a certain height, and the wall thickness between the curved surface 5 enclosed by the first semi-elliptical arc and the first semi-circular arc and the corresponding outer wall of the second air injection pipe 35 is the first wall thickness, and the wall thickness between the curved surface 5 enclosed by the second semi-elliptical arc and the second semi-circular arc and the corresponding outer wall of the second air injection pipe 35 is the second wall thickness. The thickness of the second wall thickness is greater than the first wall thickness. The flowing air also carries impurities such as dust, oil gas or debris. Under high-speed carrying, impurities such as debris directly wash the upper end cover 31, especially the second air injection pipe 35. Therefore, the wall thickness of the second air injection pipe 35 is strengthened in a targeted area, and the wall thickness is increased on the half of the wall away from the offset direction, so as to effectively resist the impact of impurities such as debris and extend the service life.

[0057] In this embodiment, since the second upper air outlet chamber 42 occupies a longer space in the horizontal direction than the first upper air outlet chamber 41, in order to make the air enter the filter unit 3 more smoothly, the angle between the center lines of the first inlet channel 11 and the second inlet channel 12 is an obtuse angle, that is, the flow direction of the air has a certain inclination before entering the filter unit 3, and the inclination direction is consistent with the inclination direction of the second air injection pipe 35, which is conducive to the docking and matching of the flow fields between the two components.

[0058] In this embodiment, two mounting claws 37 are further provided on the top of the end cover substrate 36. The two mounting claws 37 are arranged opposite to each other along the extension line of the offset direction. A reinforcing rib 38 is provided between the mounting claw 37 and the connecting portion. The mounting claw 37 is fixed to the top of the end cover substrate 36 in an outwardly inclined state. The mounting claw 37 extends to the outside of the end cover substrate 36 body. The mounting claw 37 is fixed to the upper cylinder body 1 to fix the filter unit 3, and the reinforcing rib 38 can effectively improve the connection strength between the mounting claw 37 and the second gas injection pipe 35, and the bottom of the reinforcing rib 38 is fixed to the top of the end cover substrate 36, so that the three are tightly connected.

[0059] In this embodiment, in order to achieve better sealing between the inner wall surface of the second inlet flow channel 12 and the outer wall surface of the first air injection pipe 34, two convex rings 81 are provided on the outer surface of the first air injection pipe 34. The outer edge of the convex ring 81 is elliptical in shape. A groove 82 is formed between the two convex rings 81. The groove 82 is used to place a sealing rubber ring. The convex ring 81 cooperates with the inner wall of the second inlet flow channel 12. The sealing rubber ring installed in the groove 82 has an interference fit with the inner wall of the second inlet flow channel 12 to achieve sealing and prevent gas blowby.

[0060] In this embodiment, a pressure gauge 9 is provided on the top of the upper cylinder body 1, and the pressure gauge 9 is connected to the gas inlet flow channel and / or the gas outlet chamber through pressure channels, respectively, and is used to detect the air pressure in the gas inlet flow channel and / or detect the air pressure in the gas outlet chamber near the gas outlet 14.

[0061] Compared with the prior art, the present invention provides a low-pressure difference air filter device, which controls the distance from the outer wall of the second inlet flow channel 12 to the gas inlet 13 to be smaller than the distance from the outer wall of the second inlet flow channel 12 to the gas outlet 14, increases the gap between the filter unit 3 and the inner wall of the lower cylinder body 2 to connect the gas outlet 14 to form the gas outlet chamber, reduces the pressure loss of the compressed gas due to space contraction before the gas outlet 14, and the centers of the horizontal projections of the first gas injection section and the second gas injection section on the top plane of the end cover substrate 36 do not overlap, so that the high-pressure and high-flow rate compressed air has a certain stroke of guide buffer when passing through the second gas injection pipe 35, and is injected into the filter element 32 in the direction opposite to the offset direction, forming an overall low-pressure difference flow channel in the air filter device, reducing pressure loss, saving energy input in production, and reducing production costs;

[0062] A limiting platform 15 is provided in the second inlet flow channel 12, and the inner wall surface of the second inlet flow channel 12 is divided into an upper inner wall surface 16 and a lower inner wall surface 17 from top to bottom. The upper inner wall surface 16 smoothly transitions with the inner wall surface of the first gas injection pipe 34, so that the high-pressure and high-flow rate compressed air can smoothly flow into the inner wall surface of the first gas injection pipe 34, and the first gas injection cross section is set to an elliptical shape, and the second gas injection cross section is a circular shape. The long axis length of the ellipse is greater than or equal to the diameter length of the circle, and the short axis length of the ellipse is less than or equal to the diameter length of the circle. In addition, the curved surface 5 enclosed by the first semi-elliptical arc line and the first semi-circular arc line is in a semi-funnel shape 6 that gradually shrinks from top to bottom, and the curved surface 5 enclosed by the second semi-elliptical arc line and the second semi-circular arc line is in a diffusion shape 7 that gradually diverges from top to bottom, so that a smooth transition from an elliptical shape to a circular cross section is achieved in the structure, and the high-pressure and high-flow rate air is buffered in the diffusion area to reduce the impact, and the semi-funnel contraction area realizes the collection and guidance of the air;

[0063] The air outlet chamber includes an upper air outlet chamber and a lower air outlet chamber 43, and the upper air outlet chamber includes a first upper air outlet chamber 41 and a second upper air outlet chamber 42. The compressed air processed by the filter unit 3 flows into the lower air outlet chamber 43, and then enters the upper air outlet chamber from the lower air outlet chamber 43, and is finally discharged from the gas outlet 14. Since the second upper air outlet chamber 42 is directly connected to the gas outlet 14, two symmetrical curved surfaces 5 are arranged on the inner wall surface of the upper cylinder body 1 in the second upper air outlet chamber 42, and the curved surfaces 5 are bent into the second upper air outlet chamber 42. Under the guidance of the curved surfaces 5, the compressed air coming up from the lower air outlet chamber 43 is first processed from bottom to top, and finally the compressed air is discharged from the gas outlet 14 in the horizontal direction. This flow channel arrangement has a small gas pressure loss and plays a good airflow guiding role.

[0064] Finally, it should be emphasized that the present invention is not limited to the above-mentioned implementation mode. The above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A low pressure difference air filtering device, comprising an upper cylinder, a lower cylinder and a filter unit, wherein the upper cylinder is provided with a gas inlet channel for air intake and a gas outlet for air outlet, the upper cylinder is detachably connected to the lower cylinder, the filter unit is detachably fixed to the bottom of the upper cylinder, the filter unit is gap-matched with the inner wall of the lower cylinder, the gap space between the filter unit and the inner wall of the lower cylinder together with the space enclosed by the upper cylinder downward constitutes an air outlet chamber, characterized in that: The filter unit comprises an upper end cover, a filter element and a lower end cover, the filter element is arranged between the upper end cover and the lower end cover, the upper end cover comprises a first gas injection pipe, a second gas injection pipe and an end cover substrate, the gas inlet channel comprises a first inlet channel and a second inlet channel, the first inlet channel and the second inlet channel are both hollow in the center, the first inlet channel comprises a gas inlet, the gas inlet is used to connect the intake, the second inlet channel is matched and connected with the first gas injection pipe, the inner wall shape of the second inlet channel is defined by the outer wall shape of the first gas injection pipe, and the distance from the outer wall of the second inlet channel to the gas inlet is smaller than the distance from the outer wall of the second inlet channel to the gas outlet; The first gas injection pipe and the end cover substrate are connected via a second gas injection pipe, the first gas injection pipe is hollow in the center, the second gas injection pipe is hollow in the center, the first gas injection pipe is provided with a first opening at the top end, the first gas injection pipe is provided with a second opening at the bottom end, the second gas injection pipe is provided with a third opening at the top end, the second gas injection pipe is provided with a fourth opening at the bottom end, and the end cover substrate is provided with a fifth opening at the top end; The inner contour of the fourth opening of the second gas injection pipe is consistent with the inner contour of the fifth opening on the top of the end cover substrate, the inner contour of the third opening of the second gas injection pipe is consistent with the inner contour of the second opening of the first gas injection pipe, and the second gas injection pipe realizes a smooth transition between the second opening of the first gas injection pipe and the fifth opening of the end cover substrate; The connecting cross section enclosed by the inner contour lines at the connection between the first gas injection tube and the second gas injection tube is the first gas injection cross section, the connecting cross section enclosed by the inner contour lines at the connection between the second gas injection tube and the end cover substrate is the second gas injection cross section, the first gas injection cross section is a quasi-circular shape, the second gas injection cross section is a circular shape, the center of the horizontal projection of the first gas injection cross section on the top plane of the end cover substrate is the first projection center point, the center of the horizontal projection of the second gas injection cross section on the top plane of the end cover substrate is the second projection center point, the first projection center point and the second projection center point do not overlap, and the first projection center point is located in the offset direction of the second projection center point extending along the center dividing line direction of the second gas injection cross section; At least two convex rings are arranged on the outer surface of the first gas injection pipe.

2. A low pressure difference air filter device as claimed in claim 1, characterized in that: A limiting platform is provided in the second inlet channel, and the limiting platform divides the inner wall surface of the second inlet channel into an upper inner wall surface and a lower inner wall surface from top to bottom. The upper plane of the first air injection pipe abuts against the limiting platform, and the inner contour of the connection between the upper inner wall surface and the inner wall surface of the first air injection pipe is defined by the shape of the inner wall surface of the first air injection pipe, and the inner contour of the lower inner wall surface is defined by the shape of the outer wall of the first air injection pipe.

3. A low pressure difference air filter device as claimed in claim 2, characterized in that: The first gas injection pipe is an elliptical cylinder structure with a hollow center, the first gas injection section is an elliptical shape, and the connecting line between the two foci of the first gas injection section is perpendicular to the connecting line between the first projection center point and the second projection center point.

4. A low pressure difference air filter device as claimed in claim 3, characterized in that: The long axis length of the first gas injection cross section is greater than or equal to the diameter length of the second gas injection cross section, and the short axis length of the first gas injection cross section is less than or equal to the diameter of the second gas injection cross section.

5. A low pressure difference air filter device as claimed in claim 4, characterized in that: The area of ​​the first gas injection cross section is less than or equal to the area of ​​the second gas injection cross section.

6. A low pressure difference air filter device as claimed in claim 5, characterized in that: The projection of the inner wall surface of the first inlet flow channel on the gas inlet plane is the first inlet cross section, and the horizontal projection of the inner wall surface of the second inlet flow channel on the top plane of the end cover substrate is the second inlet cross section, and the area of ​​the second inlet cross section is greater than or equal to the area of ​​the first inlet cross section.

7. A low pressure difference air filter device as claimed in claim 6, characterized in that: The air outlet chamber includes an upper air outlet chamber and a lower air outlet chamber, the upper air outlet chamber includes a first upper air outlet chamber and a second upper air outlet chamber, the first upper air outlet chamber is formed by the outer wall surface of the second inlet channel close to the gas inlet and the space enclosed by the inner wall surface of the upper cylinder body between the outer wall surface of the second inlet channel and the gas inlet, the second upper air outlet chamber is formed by the outer wall surface of the second inlet channel close to the gas outlet, the inner wall surface of the upper cylinder body between the outer wall surface of the second inlet channel and the gas outlet, and the space enclosed by the gas outlet, the lower air outlet chamber is formed by the outer surface of the filter unit and the space enclosed by the inner surface of the lower cylinder body, The dividing line between the upper air outlet chamber and the lower air outlet chamber is a horizontal plane surrounded by the upper edge of the lower cylinder body, and the dividing line between the first upper air outlet chamber and the second upper air outlet chamber is a vertical plane perpendicular to the first air injection section and coincident with the long axis of the first air injection section. Two symmetrical curved surfaces are provided on the inner wall surface of the upper cylinder body in the second upper air outlet chamber, and the curved surfaces are bent toward the second upper air outlet chamber. The curved surface includes a vertical section and an inclined section, and the vertical section and the inclined section have a smooth transition, and a rounded corner is formed at the connection between the vertical section and the inclined section, and the rounded corner protrudes out of the second upper air outlet chamber.

8. A low pressure difference air filter device according to any one of claims 3 to 7, characterized in that: The inner contour line of the fourth opening at the bottom end of the second gas injection tube is circular, the inner contour line of the third opening at the top end of the second gas injection tube is elliptical, the semi-elliptical arc line of the third opening of the second gas injection tube along the offset direction is a first semi-elliptical arc line, the semi-elliptical arc line of the third opening of the second gas injection tube along the direction opposite to the offset direction is a second semi-elliptical arc line, the semi-circular arc line of the fourth opening of the second gas injection tube along the offset direction is a first semi-circular arc line, the semi-circular arc line of the fourth opening of the second gas injection tube along the direction opposite to the offset direction is a second semi-circular arc line, the curved surface enclosed by the first semi-elliptical arc line and the first semi-circular arc line is a semi-funnel shape that gradually shrinks from top to bottom, and the curved surface enclosed by the second semi-elliptical arc line and the second semi-circular arc line is a diffusion shape that gradually diverges from top to bottom.

9. A low pressure difference air filter device as claimed in claim 8, characterized in that: The angle between the pipeline center lines of the first inlet flow channel and the second inlet flow channel is an obtuse angle.

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