Floating labyrinth sealing device
By using a floating maze sealing device in a magnetic levitation centrifuge, the sealing gap is automatically adjusted using the combination of toothed sliders and elastic rings, the problem of high leakage of traditional sealing devices is solved, significantly improving the energy efficiency of the equipment and reducing energy consumption .
Patent Information
- Application Number
- CN202310979144.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-08-04
- Publication Date
- 2025-02-14
AI Technical Summary
In magnetic levitation centrifuges, the sealing gap of traditional maze sealing devices is large, resulting in high leakage, which in turn limits the energy efficiency level and energy consumption of the equipment.
A floating maze sealing device is adopted, which includes a base, toothed slider, a press plate, an elastic ring, an O-ring, a shaft and a chuck. Through the radial floating of the toothed slider and the restoration force of the elastic ring, automatic adjustment of the sealing gap is achieved and the leakage amount is reduced.
It effectively reduces the size of the sealing gap and reduces the leakage by 66.7%-93.3%, improving the energy efficiency level of the compressor and reducing energy consumption.
Smart Images
Figure CN119435713A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the field of centrifuges, in particular to a floating labyrinth sealing device in the field of centrifuges such as magnetic suspension centrifugal compressors and magnetic suspension centrifugal blowers. Background Art
[0002] Labyrinth seal is a contactless seal, which can still leak a small amount of gas after sealing. It is also called comb-tooth seal, which is mainly used to seal the gas leaked in the centrifuge. The parts with internal leakage usually include the impeller disc and wheel cover, stage partition, rotating shaft and balance plate on the rotating shaft. Labyrinth seal is generally composed of two inner and outer rings; the outer ring has a slightly larger diameter and is a stationary part, with multiple sealing teeth at the inner diameter; the inner ring has a smaller diameter and is a rotating part, with an outer diameter generally cylindrical, and sealing grooves or sealing teeth can also be opened on the cylindrical surface. The flow of gas in the labyrinth seal is equivalent to the flow through a single sealing tooth many times. When the pressure difference at both ends of the labyrinth seal is constant, the more sealing teeth are used or the smaller the sealing gap between the sealing teeth and the rotating shaft, the smaller the leakage of the entire seal, and vice versa, the greater the leakage. The number of sealing teeth is mainly limited by the axial installation size. For example, the axial length available for installation at the wheel cover is relatively small, generally around 4-10 teeth. Some can also use stepped teeth to improve the sealing efficiency, but as the number of sealing teeth increases, the leakage reduction rate gradually decreases, and the effect is not good; the size of the sealing gap mainly depends on the machining accuracy requirements and matching accuracy requirements of the parts, and the size of the sealing gap is proportional to the leakage, which means that the smaller the sealing gap, the higher the energy efficiency of the equipment. Therefore, the size of the sealing gap also limits the maximum level of centrifuge energy efficiency.
[0003] As the mainstream trend product in the current market, the magnetic levitation centrifuge series products also have higher requirements for their performance. Magnetic levitation bearings are used at both ends of the rotating shaft of the magnetic levitation centrifuge. During operation, the rotating shaft is suspended to the center position through the magnetic levitation bearings, and then the rotating shaft is driven by the motor to rotate at high speed. In this way, there is no contact between the rotating shaft and the bearing, no mechanical friction, high efficiency, and the control accuracy is generally 1 um -10um, and the control accuracy is very high; but rolling bearings are also required at both ends of the rotating shaft to support the standby state of the centrifuge and protect against abnormal shutdown, which is indispensable; due to the manufacturing and assembly accuracy requirements, a certain bearing clearance is required to protect the bearing and the rotating shaft, and the bearing clearance is generally 0.1mm-0.2mm, and due to the debugging process requirements of the magnetic bearing and the reliability requirements of the operation process, the sealing clearance needs to be larger than the bearing clearance, generally 0.15mm-0.3mm, so the larger sealing clearance causes the leakage of the centrifuge to remain at a higher level. Summary of the invention
[0004] In order to solve the above-mentioned technical problems, the purpose of the present invention is to provide a floating labyrinth seal device, which can minimize the labyrinth seal gap of the compressor during operation and reduce leakage, thereby significantly improving the energy efficiency level of the compressor and reducing energy consumption.
[0005] In order to achieve the above-mentioned purpose, the present invention adopts the following technical solutions:
[0006] A floating labyrinth seal device comprises a base, a toothed slider, a pressure plate, an elastic ring, an O-ring, a rotating shaft and a chuck;
[0007] Preferably, the base is provided with an annular groove, and the step inside the groove is provided with four bosses evenly distributed around the circumference;
[0008] Preferably, the toothed slider is also provided with a groove, the outer diameter of the groove is equal to the inner diameter of the base groove, and the inner diameter of the base groove serves as a mechanical limit to limit the toothed slider from sliding further toward the center. Furthermore, notches are provided at both ends of the toothed slider groove, and the size of the notch matches the size of the boss of the base, and the boss of the base can limit the toothed slider from sliding circumferentially;
[0009] Preferably, the base is installed in cooperation with four toothed sliders, and the four toothed sliders are connected end to end to form a complete circle;
[0010] Preferably, an elastic ring is installed between the outer diameter of the full circle formed by the four toothed sliders and the outer step of the base groove;
[0011] Preferably, the elastic ring is in a pre-tensioned state after assembly, providing a constant centripetal force to the four toothed sliders, so that in a natural state, the outer diameter of the groove of the toothed slider just abuts against the inner diameter of the groove of the base;
[0012] Preferably, there is a gap between the inner diameter of the groove of the toothed slider and the inner diameter of the base, and the gap is a floating gap. The floating gap serves as the maximum displacement of the toothed slider in the radial direction, and the size of the floating gap is 0.2mm-0.5mm.
[0013] Preferably, a plurality of sealing teeth are provided at the inner diameter of the toothed slider, and the number of the sealing teeth is 3-6;
[0014] Preferably, a labyrinth seal is formed between the sealing teeth of the toothed slider and the rotating shaft, and the rotating shaft may be a rotor, an impeller, a balancing disk, etc. of a centrifuge. Furthermore, a gap between the inner diameter of the sealing teeth and the outer diameter of the rotating shaft is called a sealing gap, and the sealing gap is 0.02 mm-0.05 mm.
[0015] Preferably, the pressing plate is provided with two inner and outer annular grooves;
[0016] Preferably, O-rings of corresponding specifications are installed on the annular grooves on the pressing plate and fixed on the base;
[0017] Preferably, the labyrinth seal device also requires a corresponding assembly tool chuck during the installation process;
[0018] Preferably, the chuck comprises a chuck base and four set screws;
[0019] Preferably, the toothed slider is provided with a waist-shaped groove, and the pitch circle diameters of the semicircular arcs on both sides of the waist-shaped groove differ by 1 mm, and the pitch circle diameter of the semicircular arc with a larger diameter is called the large diameter side, and the smaller one is called the small diameter side;
[0020] Preferably, the pitch circle diameters of the four set screws of the chuck are equal to the large diameter side;
[0021] In summary, the advantages of the present invention are:
[0022] 1. The sealing gap size of the labyrinth seal device can be reduced to 0.02mm-0.05mm, while the general labyrinth seal gap is generally 0.15mm-0.3mm. Since the sealing gap is proportional to the leakage amount, the leakage amount can be reduced by more than 66.7%-93.3%, greatly reducing the leakage rate of the compressor.
[0023] 2. The toothed slider of the labyrinth seal device allows a floating amount of 0.2mm-0.5mm in the radial direction. When the shaft needs to move in the radial direction, up, down, left or right, the toothed slider will move with the movement of the shaft; when the centrifuge equipment is operating normally, the shaft will re-suspend to the center position, and the labyrinth seal will restore the toothed slider to the center due to the restoring force of the elastic ring, and the sealing gap will be restored to the initial state of 0.02mm-0.05mm, thereby ensuring that the centrifuge is maintained in a state of small gap, low leakage rate and high efficiency during operation.
[0024] 3. The labyrinth seal device is installed through a tooling chuck. The radial floating amount of the toothed slider can be used to expand the inner diameter of the labyrinth seal device. During the debugging and operation process, the sealing teeth can float radially to avoid radial constraints on the rotating shaft, which greatly reduces the requirements for the processing accuracy and assembly accuracy of parts and facilitates assembly. BRIEF DESCRIPTION OF THE DRAWINGS
[0025] Figure 1 It is a structural schematic diagram of a floating labyrinth seal device;
[0026] Figure 2 It is a schematic diagram of the floating mechanism of the floating labyrinth seal device;
[0027] Figure 3 is an axial cross-sectional view of a floating labyrinth seal device;
[0028] Figure 4 is a schematic diagram of the base;
[0029] Figure 5 It is a schematic diagram of a toothed slider;
[0030] Figure 6 This is a schematic diagram for installing and using the chuck;
[0031] Figure 7 is a schematic diagram of a chuck;
[0032] Figure numerals: 1, base; 2, elastic ring; 3, toothed slider; 4, pressure plate; 5, O-ring I; 6, O-ring II; 7, rotating shaft; 8, chuck; 11, base groove; 12, outer step; 13, inner step; 14, boss; 31, right groove notch; 32, left groove notch; 33, sealing tooth; 34, waist groove; 341, large diameter side; 342, small diameter side; 35, toothed slider groove; 81, chuck base; 82, set screw; a, sealing gap; b, floating gap; c, temporary gap; Implementation
[0033] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.
[0034] In the description of the present application, it should be understood that the terms "upper", "lower", "left", "right", "inside", "outside", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present application.
[0035] It should also be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not require further definition and explanation in subsequent drawings.
[0036] The specific implementation modes of the present invention will be described in detail below in conjunction with the accompanying drawings.
[0037] like Figures 1 to 5As shown, a floating labyrinth sealing device comprises a base 1, an elastic ring 2, a toothed slider 3, a pressure plate 4, an O-ring Ⅰ 5, an O-ring Ⅱ 6, a rotating shaft 7, and a chuck 8; the floating labyrinth sealing device comprises four toothed sliders 3, the four toothed sliders 3 are fitted together with the base 1, and are evenly distributed on the base 1 in a circumference, and are connected end to end on the left and right sides to form a full circle; the elastic ring 2 is installed in the gap between the inner diameter of the base groove 11 and the outer diameter of the toothed slider 3; the pressure plate 4 is fixed to the base 1 by screws; the pressure plate 4 is provided with two large and small annular grooves, and the O-ring Ⅰ 5 and O-ring Ⅱ 6 are respectively installed on the annular grooves; the O-ring Ⅰ 5 and O-ring Ⅱ 6 are distributed on the inner and outer sides of the pressure plate 4 to prevent gas leakage from the contact surface between the base 1 and the pressure plate 4.
[0038] like Figure 4 As shown, the base 1 is provided with a base groove 11; the outer side of the base groove 11 is an outer step 12, and the inner side is an inner step 13; the inner step 13 is provided with four bosses 14 evenly distributed around the circumference.
[0039] like Figure 5 As shown, the toothed slider 3 is provided with a toothed slider groove 35, and a right groove notch 31 and a left groove notch 32 are respectively provided on both sides of the toothed slider groove 35; a plurality of sealing teeth 33 are provided at the inner diameter of the toothed slider 3; a waist-shaped groove 34 with a depth of 1 mm is provided on the step of the toothed slider 3; the semicircular arc dividing circle diameters at both ends of the waist-shaped groove 34 are different in size, the left side is the small diameter side 341, and the right side is the large diameter side 342, and the small diameter is 1 mm smaller than the large diameter.
[0040] The inner diameter of the toothed slider groove 35 is smaller than the inner diameter of the inner step 13. Furthermore, a floating gap b is formed between the inner diameter of the toothed slider groove 35 and the inner diameter of the inner step 13, and the floating gap b is 0.2mm-0.5mm; further, the toothed slider 3 is assembled on two adjacent bosses 14 on the base 11, wherein the left boss clamps the left groove notch 32, and the right boss clamps the right groove notch 31; further, the toothed slider 3 can slide along the radial direction without sliding circumferentially.
[0041] The gap formed between the sealing teeth 33 and the rotating shaft 7 is the sealing gap a; the rotating shaft 7 can be a centrifuge rotor, an impeller, a balancing disk or other components; the size of the sealing gap a is proportional to the leakage of the labyrinth seal, the larger the sealing gap a, the greater the leakage, and vice versa; the size of the sealing gap a is 0.02mm-0.05mm.
[0042] The elastic ring 2 is made of elastic material, which may be rubber or a spring, and can provide sufficient restoring force; wherein the elastic ring 2 is in a pre-tensioned state in a natural state, providing centripetal force to the toothed slider 3 .
[0043] The material of the toothed slider 3 is softer than that of the shaft, and is generally made of aluminum alloy or babbitt alloy.
[0044] like Figure 2 As shown, the gap between the inner diameter of the base groove 11 and the outer diameter of the toothed slider groove 35 is a temporary gap c; the temporary gap c is 0 mm in a natural state; when the rotating shaft 7 needs to move upward, the rotating shaft 7 contacts the sealing teeth 33, and the toothed slider 3 moves upward with the rotating shaft 7. At this time, the floating gap b gradually decreases, and the temporary gap c increases accordingly; and when the rotating shaft 7 returns to the center position, the toothed slider 3 returns to the initial state due to the restoring force of the elastic ring 2, so that the sealing gap a and the floating gap b return to the initial value, and the temporary gap c returns to 0 mm.
[0045] like Figure 6 to Figure 7 As shown, the chuck 8 includes a chuck base 81 and four set screws 82; the set screws 82 are evenly distributed on the chuck base 81 along the circumference, and the pitch circle diameter thereof is equal to the pitch circle diameter of the right large diameter side 342; the diameter of the end of the set screw 82 is equal to the width of the waist-shaped groove 34; when installing the floating labyrinth seal device, the four set screws 82 of the chuck 8 are aligned with the large diameter side 342 for assembly; further, the chuck 8 is rotated counterclockwise, and the toothed slider 3 slides outward along the radial direction, thereby expanding the inner diameter of the labyrinth seal for easy installation.
[0046] The floating labyrinth seal device is a contactless labyrinth seal, which is particularly suitable for the field of magnetic levitation centrifugal machines such as magnetic levitation centrifugal compressors and magnetic levitation centrifugal blowers. Its sealing teeth are evenly divided into four equal parts in the circumferential direction, and each piece, called a toothed slider, can slide radially independently. After deviating from the center position, it can be restored to the center position through the restoring force of the elastic ring. In actual operation, there is no need to worry about contact and friction between the rotor and the sealing teeth. Since the sealing teeth and the rotating shaft are in soft contact, the rotating shaft can still float at the predetermined center and rotate normally. After the rotating shaft rotates at high speed, it will not continue to rub after a certain wear on the sealing teeth, which will not affect the normal use of the labyrinth seal.
[0047] The above is a description of the embodiments of the present invention. Through the above description of the disclosed embodiments, professionals and technicians in the field can implement or use the present invention. Various modifications to these embodiments will be apparent to professionals and technicians in the field. The general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown in this article, but will conform to the widest range consistent with the principles and novelties disclosed herein.
Claims
1. A floating labyrinth seal device, characterized in that The invention comprises a base (1), an elastic ring (2), a toothed slider (3), a pressure plate (4), an O-ring I (5), an O-ring II (6), a rotating shaft (7) and a chuck (8). The base (1) and the four toothed sliders (3) are fitted together. The four toothed sliders (3) are evenly distributed on the base (1) and connected end to end to form a full circle. The elastic ring (2) is installed in the gap between the inner diameter of the base groove (11) and the outer diameter of the toothed slider (3). The pressure plate (4) is fixed to the base (1) by screws. The pressure plate (4) is provided with two large and small annular grooves, and the O-ring I (5) and O-ring II (6) are installed on the annular grooves respectively.
2. A floating labyrinth seal device according to claim 1, characterized in that The base (1) is provided with a base groove (11), an outer step (12), an inner step (13) and four circumferentially evenly distributed bosses (14); the toothed slider (3) is provided with a right groove notch (31), a left groove notch (32) and a toothed slider groove (35); the four toothed sliders (3) are respectively installed between two adjacent bosses (14); the right groove notch (31) abuts against the boss (14) on the right side, and the left groove notch (32) abuts against the boss (14) on the left side; the four toothed sliders (3) are connected end to end to form a full circle; the inner diameter of the base groove (11) and the outer diameter of the toothed slider groove (35) form a temporary gap (c); the temporary gap (c) has a gap value of 0 mm in a natural state; when the toothed slider (3) slides outward along the radial direction along the rotating shaft (7), the temporary gap (c) gradually increases; the inner diameter of the inner step (13) and the inner diameter of the toothed slider groove (35) form a floating gap (b) The floating gap (b) is 0.2 mm to 0.5 mm in size, and the floating gap (b) gradually decreases when the toothed slider (3) slides outward along the radial direction along the rotating shaft (7).
3. A floating labyrinth seal device according to claim 1, characterized in that The inner diameter of the toothed slider (3) is provided with a plurality of sealing teeth (33), a labyrinth seal is formed between the sealing teeth (33) and the rotating shaft (7), and a sealing gap a is formed between the inner diameter of the sealing teeth (33) and the outer diameter of the rotating shaft (7), and the size of the sealing gap (a) is 0.02mm-0.05mm.
4. A floating labyrinth seal device according to claim 1, characterized in that A waist-shaped groove (34) with a depth of 1 mm is provided on the step of the toothed slider (3). The semicircular arc dividing circles at both ends of the waist-shaped groove (34) have different diameters. The left side is the small diameter side (341) and the right side is the large diameter side (342). The small diameter is 1 mm smaller than the large diameter.
5. A floating labyrinth seal device according to claim 1, characterized in that The chuck (8) is provided with a chuck base (81) and four set screws (82), and the pitch circle diameter of the four set screws (82) is equal to the pitch circle diameter of the large diameter side (342).
6. A floating labyrinth seal device according to claims 1 to 5, characterized in that After being assembled, the elastic ring (2) is in a pre-tensioned state, providing a restoring force for the toothed slider (3) to slide toward the center.
7. A floating labyrinth seal device according to claims 1 to 5, characterized in that O-rings I (5) and II (6) are distributed on the inner side and the outer side of the pressing plate (4) to prevent gas from leaking from the contact surface between the base (1) and the pressing plate (4).