Gas compressor equipment for extracting small molecule gas

Abstract

The utility model discloses a gas compressor device for extracting small molecule gas, the gas compressor device is provided with a shell and a Roots blower device, the Roots blower device is arranged in an inner cavity and comprises an impeller assembly, the impeller assembly comprises a pair of impellers, the pair of impellers are located in an impeller cavity, the impellers are centrosymmetric components and are provided with three blades, and the blades of the pair of impellers are meshed with each other; wherein the outer contour shape of each lobe blade is composed of a left half outer contour shape and a right half outer contour shape which are mutually mirrored; according to the direction from the blade top to the blade root of the blade, the outer contour shape of the left half part is provided with a blade top center point, a blade center point, a first transition point, a second transition point, a third transition point, a fourth transition point and a blade root center point; the outer contour shape of the left half part is composed of a blade top opposite rolling arc section, a transition arc section, an involute section, an arc envelope line section, a point meshing cycloid section and a blade root opposite rolling arc section.

Description

Technical Field

[0001] This application relates to the technical field of compressors, and particularly to a compressor device for extracting small molecule gases and including a Roots blower device. Background Art

[0002] In some large-scale equipment equipped with gas monitoring systems, it is often necessary to use a compressor device to transport the sampled gas to the gas monitoring point so that the monitoring device can complete the monitoring process at the monitoring point. For the monitoring of some small molecule gases, such as argon isotope gas, hydrogen isotope gas, etc., during the process of transporting the gas by the compressor device, it is necessary to avoid problems such as gas leakage.

[0003] A Roots blower is a rotary positive displacement twin-rotor gas transportation device that can be used as a blower and a vacuum pump. It compresses and transports gas by the rotary motion of two or three impeller rotors in the cylinder volume chamber. The two rotor impellers of the Roots blower do not contact each other, and the sealing is achieved by a reasonable clearance tolerance. Thanks to this sealing method, the gas transported by the Roots blower will not be contaminated by mixing with oil. The structural characteristics and operating principle of the Roots blower determine that the Roots blower does not require lubricant, and it has the advantages of high energy efficiency, stable exhaust pressure, high precision, and long working life, making it have obvious advantages in transporting conventional gases and flammable, explosive, and corrosive gases.

[0004] The Roots blower is easily affected by backflow impact and inlet and outlet pressure pulsation during use, which requires high reliability of the materials. At present, the Roots blowers introduced on the market are mainly applied to occasions with large flow rates and unrestricted use space, and there is a lack of research on Roots blowers suitable for small flow rate gas transportation and small size. Summary of the Utility Model

[0005] In order to solve the above technical problems, the purpose of this application is to provide a compressor device that can achieve the transportation of small molecule gases with small flow rates and low leakage rates.

[0006] To achieve the above object, the present application adopts the following technical solution: A compressor device for extracting small molecule gas, having a housing and a Roots blower device. The housing defines an inner cavity and an air inlet and an air outlet that are in fluid communication with the inner cavity. The Roots blower device is disposed in the inner cavity and includes: an inner housing that defines an impeller cavity and one or more suction ports and one or more exhaust ports that are in fluid communication with the impeller cavity. The one or more suction ports are in fluid communication with the air inlet, and the one or more exhaust ports are in fluid communication with the air outlet. And an impeller assembly, including a first shaft extending along a first axis, a second shaft extending along a second axis parallel to the first axis, and a pair of impellers respectively mounted on the first shaft and the second shaft. The pair of impellers are located in the impeller cavity and are configured to convey the gas to be transported from the one or more suction ports to the one or more exhaust ports. The impellers are centrosymmetric members and have three-lobe blades, and the blades of the pair of impellers mesh with each other. Wherein, the outer contour shape of each lobe of the blade is composed of a left half outer contour shape and a right half outer contour shape that are mirror images of each other. In the direction from the blade tip to the blade root, the left half outer contour shape has a blade tip center point, a blade tip apex point, a first transition point, a second transition point, a third transition point, a fourth transition point, and a blade root center point. The left half outer contour shape is composed of a blade tip rolling arc segment located between the blade tip center point and the blade tip apex point, a transition arc segment located from the blade tip apex point to the first transition point, an involute segment located between the first transition point and the second transition point, an arc envelope segment located between the second transition point and the third transition point and meshing with the transition arc segment, a point meshing cycloid segment located between the third transition point and the fourth transition point and meshing with the blade tip apex point, and a blade root rolling arc segment located between the fourth transition point and the blade root center point and meshing with the blade tip rolling arc segment.

[0007] In the above technical solution, preferably, the impellers are all cast iron impellers. There is a first meshing gap between the blades of the pair of impellers. The pair of impellers define an outer perimeter boundary, and the inner housing has an inner perimeter boundary that defines the inner diameter of the impeller cavity. There is a second gap between the outer perimeter boundary and the inner perimeter boundary, and the first meshing gap is less than or equal to 2 times the second gap.

[0008] In the above technical solution, preferably, the inner housing includes a cylindrical barrel, a front wall plate that is hermetically joined to the front end face of the barrel, and a rear wall plate that is hermetically joined to the rear end face of the barrel. The front and rear end portions of the first shaft respectively pass through the front wall plate and the rear wall plate, and the front end portion of the second shaft passes through the front wall.

[0009] In the above technical solution, preferably, the pair of impellers define a front base surface perpendicular to the first axis and a rear base surface perpendicular to the first axis. There is a third gap between the front base surface and the front wall plate, and a fourth gap between the rear base surface and the rear wall plate. The third gap, the fourth gap, and the first meshing gap are equal.

[0010] In the above technical solution, preferably, the one or more air inlets are located on the cylinder body.

[0011] In the above technical solution, preferably, the number of the air inlets is multiple.

[0012] In the above technical solution, preferably, the one or more air outlets are located on the rear wall plate.

[0013] In the above technical solution, preferably, the Roots blower device further includes: a gearbox, the gearbox is disposed in the inner cavity and includes a box body and a first gear and a second gear located in the box body. The rear end portion of the box body is hermetically joined to the front wall plate. The first gear meshes with the second gear. The front end portion of the first shaft extends into the box body, and the first gear is mounted on the first shaft. The front end portion of the second shaft extends into the box body, and the second gear is mounted on the second shaft. Wherein, there is a second meshing gap between the first gear and the second gear, and the second meshing gap is less than or equal to 1 / 3 of the first meshing gap.

[0014] The Roots blower device further includes: a motor assembly, the motor assembly is placed in the inner cavity and includes a stator, a rotor, and a motor shaft. The motor shaft is coupled to the rear end portion of the first shaft through a coupling.

[0015] In the above technical solution, preferably, the air inlet and the air outlet are respectively located at the front end portion and the rear end portion of the outer shell.

[0016] The present application has the following beneficial effects compared with the prior art: Through the design of the outer contour shape of the blades of the impellers, while ensuring the rotation and meshing of the pair of impellers, the leakage amount of gas from the meshing gap of the pair of impellers is significantly reduced, thereby ensuring the gas transportation capacity of the compressor equipment. And the gas transportation flow rate of the compressor equipment is small, the pressure is low, there is no oil stain, it has corrosion resistance, good stability, small volume, and long service life, and is especially suitable for the transportation of small molecule gases. Description of the Drawings

[0017] Figure 1Schematic structural diagram of a compressor device for extracting small-molecule gas provided by an embodiment of the present application;

[0018] Figure 2 For Figure 1 Side view of the compressor device;

[0019] Figure 3 For Figure 2 Cross-sectional view along the A-A direction;

[0020] Figure 4 For Figure 3 Cross-sectional view along the B-B direction;

[0021] Figures 5a - 5e Schematic diagram of the suction, compression, and exhaust working processes of the Roots blower device provided by an embodiment of the present application;

[0022] Figure 6 Schematic diagram of the outer contour shape of the first impeller provided by an embodiment of the present application;

[0023] Figure 7 Schematic diagram of the gap between the first impeller and the second impeller provided by an embodiment of the present application. Detailed implementation manners

[0024] To describe in detail the technical content, structural features, achieved objectives, and effects of the application, the technical solutions in the embodiments of the present application will be described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. In the following description, for the purpose of explanation, many specific details are set forth to provide a detailed description of various exemplary embodiments or implementations of the present application. However, various exemplary embodiments can also be implemented without these specific details or in the case of one or more equivalent arrangements. In addition, various exemplary embodiments can be different, but they do not have to be exclusive. For example, without departing from the concept of the present application, the specific shapes, structures, and characteristics of the exemplary embodiments can be used or implemented in another exemplary embodiment.

[0025] Refer to Figure 1 , Figure 2 And Figure 3 As shown, it shows a compressor device of the present application, which can be used to extract small-molecule gas so as to transport the small-molecule gas from one location to another location.

[0026] The compressor device 100 mainly includes a closed outer casing 10 and a Roots blower device 20 disposed within the outer casing 10. The outer casing 1 defines an inner cavity 11, as well as an air inlet 12 and an air outlet 13 that are in fluid communication with the inner cavity 11. The Roots blower device 20 includes an inner casing 2, an impeller assembly 3, a gearbox 4, a bearing assembly 5, and a motor assembly 6. The Roots blower device 20 provides a flow driving force for the gas to flow from the air inlet 12 to the air outlet 13.

[0027] In the embodiments of the present application, the air inlet 12 and the air outlet 13 are respectively located at the front end portion and the rear end portion of the closed outer casing 1. In some specific embodiments, the closed outer casing 1 may be assembled from a plurality of outer casing bodies. In the present embodiment, the closed outer casing 1 includes a cap-shaped front outer casing body 101, a cap-shaped rear outer casing body 102, and an intermediate connecting outer casing body 103. The air inlet 12 is located at the front part of the front outer casing body 101, and the air outlet 13 is located at the rear part of the rear outer casing body 102. The rear part of the front outer casing body 101 has a flange-like flange 1011, and the front part of the rear outer casing body 102 has a flange-like flange 1021. The flange-like flange 1011, the flange-like flange 1021, and the connecting outer casing body 103 are fixedly joined together by a plurality of threaded fasteners 104.

[0028] The inner casing 2 is disposed in the inner cavity 11 of the outer casing 1. In this example, the inner casing 2 is placed in a corresponding part of the inner cavity 11 of the front outer casing body 101. In the present embodiment, the inner casing 2 includes a cylindrical barrel 201, a front wall panel 202 that is sealingly joined to the front side end face of the barrel 201, and a rear wall panel 203 that is sealingly joined to the rear side end face of the barrel 201. As Figure 4 shown, the inner casing 2 defines an impeller cavity 21, as well as a plurality of suction ports 22 and exhaust ports 23 that are in fluid communication with the impeller cavity 21. The plurality of suction ports 22 are located on the barrel 201, and the exhaust ports 23 are located on the rear wall panel 203.

[0029] Continuing as Figure 3 shown, an air inlet passage 111 is formed within the inner cavity 11 outside the inner casing 2; the air inlet passage 111 is in fluid communication with the air inlet 12 and the plurality of suction ports 22. Similarly, an air outlet passage 112 is formed within the inner cavity 11 outside the inner casing 2. The air outlet passage 112 is in fluid communication with the air outlet 13 and the exhaust ports 23.

[0030] The impeller assembly 3 includes a first shaft 31 extending along a first axis X1, a first impeller 32 mounted on the first shaft 31, a second shaft 33 extending along a second axis X2 parallel to the first axis X1, and a second impeller 34 mounted on the second shaft 33. The first impeller 32 and the second impeller 34 are located within the impeller cavity 21 and are configured to convey the gas from the plurality of suction ports 22 to the exhaust ports 23. Referring to FIG. 4, the first impeller 32 and the second impeller 34 are centrally symmetric members of the same specification and each has three-vane blades, and the blades of the first impeller 32 mesh with the blades of the second impeller 34.

[0031] Continue to refer to Figure 3 , the gearbox 4 is arranged in the inner cavity 11 and is located on the front side of the inner housing 2. The gearbox 4 includes a box body 41 and a first gear 42 and a second gear 43 located inside the box body 41. The rear end of the box body 41 is hermetically joined to the front wall panel 202 by a plurality of threaded fasteners 44. The first gear 42 and the second gear 43 mesh with each other.

[0032] The bearing assembly 5 is located in the inner cavity 11 and is located on the rear side of the inner housing 2. The bearing assembly 5 provides a pair of first bearings 51 arranged front and back and a pair of second bearings 52 arranged front and back. The first bearings 51 and the second bearings 52 are both supported on the rear wall panel 23, and these bearings will help support the first shaft 31 and the second shaft 33.

[0033] The motor assembly 6 is built into the inner cavity 11 and is located on the rear side of the bearing assembly 5. In this example, the motor assembly 6 is placed in a part of the inner cavity 11 corresponding to the front outer housing 101. The motor assembly 6 includes a stator 61, a rotor 62 located inside the stator 61, and a motor shaft 63 fixed to the center of the rotor 62.

[0034] The first shaft 31 is supported on a pair of first bearings 51. The front end of the first shaft 31 passes through the front wall panel 202 and extends into the box body 41. A third bearing 53 is arranged between the first shaft 31 and the front wall panel 202. The third bearing 53 is located inside the box body 41. The rear end of the first shaft 31 and the front end of the motor shaft 53 are coupled to each other by a coupling 7. The front end of the second shaft 32 also passes through the front wall panel 202 and extends into the box body 41. A fourth bearing 54 is arranged between the second shaft 31 and the front wall panel 202. The fourth bearing 53 is located inside the box body 41. The second gear 42 is installed on the second shaft 32.

[0035] As Figure 5a , Figure 5b , Figure 5c , Figure 5d and Figure 5e shown, when the compressor equipment is working, relying on the first impeller 32 and the second impeller 34 of the Roots blower device 20 to rotate in opposite directions at the same speed, the suction, compression, and exhaust processes of the entire gas 800 to be transported are realized; among them, Figure 5a is the suction process, Figure 5b , Figure 5c , Figure 5d is the compression process, Figure 5e is the exhaust process. For a three-lobe rotor, six suction and exhaust processes are completed in one working cycle. Compared with a two-lobe rotor that can only complete four suction and exhaust processes in one working cycle, its working efficiency is higher.

[0036] Refer to Figure 6, which shows a schematic structural diagram of the first impeller 32 according to an embodiment of the present application. The first impeller 32 is a centrally symmetric member and is composed of three vanes 321, 322, and 323 with exactly the same outer contour shape. Taking the vane 321 as an example, the specific shape of the vane will be described in detail below.

[0037] The outer contour shape of the vane 321 is composed of a left half outer contour shape 3211 and a right half outer contour shape 3212 that are mirror images of each other. In the direction from the tip to the root of the vane, the left half outer contour shape 3211 has a tip center point A, a tip apex point B, a first transition point C, a second transition point D, a third transition point E, a fourth transition point F, and a root center point G. The left half outer contour shape is composed of a tip rolling arc segment AB between the tip center point A and the tip apex point B, a transition arc segment BC from the tip apex point B to the first transition point C, an involute segment CD between the first transition point C and the second transition point D, an arc envelope segment DE between the second transition point D and the third transition point E that meshes with the transition arc segment, a point meshing cycloid segment EF between the third transition point E and the fourth transition point F that meshes with the tip apex point B, and a root rolling arc segment FG between the fourth transition point F and the root center point G that meshes with the tip rolling arc segment.

[0038] In a specific embodiment, the parameter ranges of each segment of the left half outer contour shape 3211 of the vane 321 can be calculated as follows. Among the basic parameters, A is the impeller center distance, and D is the theoretical meshing diameter of the impeller; see Figure 6 the pitch circle radius R marked in p and the impeller radius R. The pitch circle radius Rp = A / 2, and the impeller radius R = D / 2; in the following formula, α1 can take (2:4)°, and z = 3.

[0039] (1) Segment AB

[0040] Segment AB is a tip rolling arc with a radius of R to ensure the tip seal of the impeller. Its parametric equation is

[0041]

[0042] where (α2 is shown in the description of “(2) Segment BC” below)

[0043] (2) Segment BC

[0044] Segment BC is an arc with a center on the involute base circle and a radius of r1. Its parametric equation is as follows:

[0045]

[0046] where r2 = ro ; α2 = α e -β e ; r1 = R e sinα e ; (r o , α e , β e , R e See the description of the following “(III) CD segment”.

[0047] (III) CD segment

[0048] The CD segment is an involute, and its parametric equations are as follows:

[0049]

[0050] tanα e ≥ t ≥ tanα b

[0051] where r o is the involute base circle radius, the base circle correction coefficient ε1 = 0.9; α p is the pitch circle pressure angle, the radii of the arcs where the involute starting point D and ending point C are located are respectively: The involute segment contact ratio ε2 = 0.3; the pressure angles corresponding to the involute starting point D and ending point C are respectively: The polar angles corresponding to the involute starting point D and ending point C are respectively:

[0052] (IV) DE segment

[0053] The DE segment is an arc envelope that meshes with the arc segment BC, and its parametric equations are as follows:

[0054]

[0055] where,

[0056] (V) EF segment

[0057] The EF segment is a point-contact cycloid that meshes with the blade tip B, and its parametric equations are as follows:

[0058]

[0059] where, r E is the polar radius of point E and can be obtained from the parametric equations in “(IV) DE segment”.

[0060] (VI) FG segment

[0061] The FG section is the root rolling arc section that meshes with the tip rolling arc section AB of the blade. Its parametric equations are as follows:

[0062]

[0063] Between the first impeller 32 and the second impeller 34 of the present application, in order to ensure no collision and abrasion between the impellers or between the impellers and the machine body, and taking into account factors such as thermal expansion, deformation under load, clearance of synchronous gears and bearings, and machining and installation, gaps are provided between the first impeller 32 and the second impeller 34, between the first impeller 32 and the second impeller 34 and the front wall panel 202, between the first impeller 32 and the second impeller 34 and the rear wall panel 203, and between the outer perimeters of the first impeller 32 and the second impeller 34 and the impeller cavity 21, specifically as follows:

[0064] As Figure 7 shown, both the first impeller 32 and the second impeller 34 are cast iron impellers and there is a first meshing gap d1 between them.

[0065] Continuing to refer to Figure 4 , the impeller assembly 3 defines an outer perimeter boundary C1, and the inner shell 2 has an inner perimeter boundary C2 that defines the inner diameter of the impeller cavity 21. There is a second gap d2 between the outer perimeter boundary C1 and the inner perimeter boundary C2, and the first meshing gap d1 is less than or equal to 2 times the second gap d2; preferably, the first meshing gap d1 is equal to 2 times the second gap d2.

[0066] Continuing to refer to Figure 3 , the first impeller 32 and the second impeller 34 define a front end base surface F1 perpendicular to the first axis X1 and a rear end base surface F2 perpendicular to the first axis X1. There is a third gap d3 between the front end base surface X1 and the front wall panel 202, and a fourth gap d4 between the rear end base surface F2 and the rear wall panel 203. The third gap d3, the fourth gap d4, and the first meshing gap d1 are equal.

[0067] In addition, there is a second meshing gap (not marked in the figure) between the first gear 42 and the second gear 43, and the second meshing gap is less than or equal to 1 / 3 of the first meshing gap d1.

[0068] The above shows and describes the basic principles, main features, and advantages of the present application. Those skilled in the art should understand that the present application is not limited by the above embodiments. What is described in the above embodiments and the specification only illustrates the principles of the present application. Without departing from the spirit and scope of the present application, the present application will have various changes and improvements. The scope of protection required by the present application is defined by the appended claims, the specification, and their equivalents.

Claims

1. A compressor device for extracting small molecule gas, comprising a housing and a Roots blower device, wherein the housing defines an inner cavity and an air inlet and an air outlet in fluid communication with the inner cavity; characterized in that: The Roots blower device is arranged in the inner cavity and comprises: an inner casing defining an impeller chamber and one or more air intake ports and one or more air exhaust ports in fluid communication with the impeller chamber, wherein the one or more air intake ports are in fluid communication with the air inlet port, and the one or more air exhaust ports are in fluid communication with the air outlet port; and An impeller assembly, comprising a first shaft extending along a first axis, a second shaft extending along a second axis parallel to the first axis, and a pair of impellers respectively mounted on the first shaft and the second shaft, wherein the pair of impellers are located in the impeller chamber and are configured to transport the gas to be transported from the one or more air inlets to the one or more air outlets, the impeller being a centrally symmetrical component and having three-petal blades, and the blades of the pair of impellers are meshed with each other; The outer contour shape of each petal of the blade is composed of a left half outer contour shape and a right half outer contour shape which are mirror images of each other; in the direction from the tip of the blade to the root of the blade, the left half outer contour shape has a tip center point (A), a tip point (B), a first transition point (C), a second transition point (D), a third transition point (E), a fourth transition point (F) and a root center point (G); the left half outer contour shape is composed of a tip rolling arc segment located between the tip center point (A) and the tip point (B), a tip arc segment located from the tip point (B) to the The blade tip is composed of a transition arc segment of the first transition point (C), an involute segment between the first transition point (C) and the second transition point (D), an arc envelope segment between the second transition point (D) and the third transition point (E) and meshing with the transition arc segment, a point-meshing cycloid segment between the third transition point (E) and the fourth transition point (F) and meshing with the tip point (B), and a blade root rolling arc segment between the fourth transition point (F) and the blade root center point (G) and meshing with the tip rolling arc segment.

2. The compressor equipment according to claim 1, characterized in that: The impeller is a cast iron impeller, and there is a first meshing gap between the blades of the pair of impellers. The pair of impellers define an outer peripheral boundary, and the inner shell has an inner peripheral boundary that defines the inner diameter of the impeller cavity. There is a second gap between the outer peripheral boundary and the inner peripheral boundary, and the first meshing gap is less than or equal to twice the second gap.

3. The compressor equipment according to claim 2, characterized in that: The inner shell includes a cylindrical body, a front wall plate sealed with the front end face of the body, and a rear wall plate sealed with the rear end face of the body. The front and rear ends of the first axis pass through the front wall plate and the rear wall plate respectively, and the front end of the second axis passes through the front wall.

4. The compressor equipment according to claim 3, characterized in that: The pair of impellers define a front end base surface perpendicular to the first axis and a rear end base surface perpendicular to the first axis, a third gap is provided between the front end base surface and the front wall plate, a fourth gap is provided between the rear end base surface and the rear wall plate, and the third gap, the fourth gap and the first meshing gap are equal.

5. The compressor equipment according to claim 3, characterized in that: The one or more air inlets are located on the cylinder.

6. The compressor equipment according to claim 5, characterized in that: The number of the air intake ports is multiple.

7. The compressor equipment according to claim 3, characterized in that: The one or more exhaust ports are located on the rear wall panel.

8. The compressor equipment according to claim 3, characterized in that: The Roots blower device also includes: a gear box, which is arranged in the inner cavity and includes a box body and a first gear and a second gear located in the box body, the rear end of the box body is sealingly engaged with the front wall panel, the first gear and the second gear are meshed with each other, the front end of the first shaft extends into the box body, the first gear is installed on the first shaft, the front end of the second shaft extends into the box body, and the second gear is installed on the second shaft; wherein, there is a second meshing gap between the first gear and the second gear, and the second meshing gap is less than or equal to 1 / 3 of the first meshing gap.

9. The compressor equipment according to claim 3, characterized in that: The Roots blower device further comprises: a motor assembly, which is placed in the inner cavity and comprises a stator, a rotor and a motor shaft, and the motor shaft is coupled to the rear end of the first shaft through a coupling.

10. The compressor equipment according to claim 1, characterized in that: The air inlet and the air outlet are respectively located at the front end and the rear end of the shell.

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