Stator for a vacuum pump
By using a combination of SG iron and NiP alloy materials on the vacuum pump stator, and designing grooves and partial plating, the leakage problem of vacuum pump seals during fluid flow was solved, achieving more efficient sealing and mechanical stability, and improving the performance of the vacuum pump.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- EDWARDS KOREA
- Filing Date
- 2024-10-31
- Publication Date
- 2026-06-19
AI Technical Summary
The seals of existing vacuum pumps are difficult to seal effectively when fluid is flowing, especially under pressure differential, which leads to leakage and performance degradation.
By employing a combination of spheroidal graphite (SG) iron and nickel-phosphorus (NiP) alloy materials, and through the design of grooves and plating technology on the stator surface, local sealing and protection of stator components are achieved, avoiding direct contact and chemical reactions.
It improves the sealing performance and mechanical stability of the vacuum pump, reduces chemical reactions and wear, maintains the lubrication effect between the rotor and stator, and enhances the pump's operating efficiency and reliability.
Smart Images
Figure CN122249642A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a stator for a vacuum pump, a vacuum pump, and a method for forming a stator for a vacuum pump. Background Technology
[0002] Rotating machines (such as compressors or vacuum pumps) require careful design and manufacture so that moving parts can precisely cooperate with each other. Providing effective seals to seal the machine tends to be problematic, especially when fluid flow is driven by a pressure difference between the machine and the surrounding environment. Improved seals are desired. Summary of the Invention
[0003] In one aspect, a vacuum pump stator is provided, including a first stator component and a second stator component, the first stator component having a first surface and the second stator component having a second surface. At least one of the first surface or the second surface includes one or more grooves. The first stator component and the second stator component are configured to be sealingly connected to each other when at least a portion of the first surface abuts against at least a portion of the second surface, thereby defining one or more pumping chambers between the first stator component and the second stator component, each of the one or more pumping chambers being at least partially defined by a corresponding groove of the one or more grooves. The first stator component and the second stator component are formed of a first material. At least a portion of each of the first surface and the second surface is an uncoated portion formed of the first material that at least partially defines the one or more pumping chambers when the first stator component and the second stator component are sealingly connected to each other when at least a portion of the first surface abuts against at least a portion of the second surface. Each of the first surface and the second surface includes at least a portion thereof, wherein when the first stator component and the second stator component are sealed to each other with at least a portion of the first surface abutting against at least a portion of the second surface, the at least a portion of the one or more pumping chambers is not limited to being coated with a second material, the second material being different from the first material.
[0004] The first material can be spheroidal graphite (SG) iron.
[0005] The second material can be a nickel-phosphorus (NiP) alloy.
[0006] The first surface may be an unplated portion formed of the first material such that when the first stator component and the second stator component are sealed to each other with at least a portion of the first surface abutting against at least a portion of the second surface, the integral at least partially defines the one or more pumping chambers.
[0007] The first surface may be plated with the second material in the following manner: when the first stator component and the second stator component are sealed to each other with at least a portion of the first surface abutting at least a portion of the second surface, the integral does not define the one or more pumping chambers.
[0008] When the first stator component and the second stator component are sealed to each other with at least a portion of the first surface abutting against at least a portion of the second surface, the entirety of the second surface defining the one or more pumping chambers may be an unplated portion formed of the first material.
[0009] The second surface may be plated with the second material in the following manner: when the first stator component and the second stator component are sealed to each other with at least a portion of the first surface abutting at least a portion of the second surface, the integral does not define the one or more pumping chambers.
[0010] The first stator component and the second stator component may include corresponding ends that are arranged to receive a vacuum pump heat shield when the first stator component and the second stator component are sealed to each other with at least a portion of the first surface abutting against at least a portion of the second surface. At least a portion of each of the ends may be coated with the second material.
[0011] In another aspect, a vacuum pump is provided, the vacuum pump comprising a vacuum pump stator as described in any of the preceding aspects, wherein a first stator component and a second stator component are hermetically connected to each other with at least a portion of the first surface abutting against at least a portion of the second surface, thereby defining the one or more pumping chambers between the first stator component and the second stator component; and one or more rotors arranged to rotate within the one or more pumping chambers.
[0012] The vacuum pump may further include one or more sealing devices disposed between at least a portion of the first surface and at least a portion of the second surface.
[0013] The vacuum pump may include one or more vacuum pump insulation plates, each vacuum pump insulation plate being hermetically attached to a corresponding end of the vacuum pump stator.
[0014] On another front, a method of forming a vacuum pump stator is provided, the method comprising: providing a first stator component having a first surface, the first stator component being formed of a first material; and providing a second stator component having a second surface, the second stator component being formed of the first material; wherein at least one of the first surface or the second surface includes one or more grooves; the first stator component and the second stator component are configured to be sealingly connected to each other when at least a portion of the first surface abuts against at least a portion of the second surface, thereby defining one or more pumping chambers, each of the one or more pumping chambers being at least partially defined by a corresponding groove of the one or more grooves; and the The method further includes: coating at least a portion of each of the first surface and the second surface with a second material such that, when the first stator component and the second stator component are sealed to each other with at least a portion of the first surface abutting against at least a portion of the second surface, the at least a portion does not define the one or more pumping chambers, the second material being different from the first material; and maintaining at least a portion of each of the first surface and the second surface in an uncoated state such that, when the first stator component and the second stator component are sealed to each other with at least a portion of the first surface abutting against at least a portion of the second surface, the at least a portion at least partially defines the one or more pumping chambers.
[0015] The maintenance may include: during the plating process, shielding each of the first and second surfaces with at least a portion thereof, wherein the at least a portion at least partially defines the one or more pumping chambers when the first stator component and the second stator component are sealed to each other with at least a portion of the first surface abutting against at least a portion of the second surface.
[0016] On another front, a vacuum pump stator is provided, comprising: a first stator component having a first surface; and a second stator component having a second surface; wherein at least one of the first surface or the second surface includes one or more grooves; the first stator component and the second stator component are configured to be sealingly connected to each other when at least a portion of the first surface abuts against at least a portion of the second surface, thereby defining one or more pumping chambers, each of the one or more pumping chambers being at least partially defined by a corresponding groove of the one or more grooves; the first stator component and the second stator component are formed of a first material; the first surface includes: a first surface portion that at least partially defines the one or more pumping chambers when the first stator component and the second stator component are sealingly connected to each other when at least a portion of the first surface abuts against at least a portion of the second surface, the first surface portion being an uncoated surface formed of the first material. The first stator component and the second stator component are sealed to each other with at least a portion of the first surface abutting against at least a portion of the second surface, the second surface portion not defining the one or more pumping chambers, the second surface portion being plated with a second material different from the first material; and the second surface includes: a third surface portion, which at least partially defines the one or more pumping chambers when the first stator component and the second stator component are sealed to each other with at least a portion of the first surface abutting against at least a portion of the second surface, the third surface portion being an unplated surface portion formed of the first material; and a fourth surface portion, which does not define the one or more pumping chambers when the first stator component and the second stator component are sealed to each other with at least a portion of the first surface abutting against at least a portion of the second surface, the fourth surface portion being plated with the second material.
[0017] In another aspect, a vacuum pump stator is provided, comprising: a first stator component having a first mating surface; and a second stator component having a second mating surface; wherein the first stator component and the second stator component are formed of a first material; the first mating surface includes a first sealing portion and a first pumping chamber portion; the second mating surface includes a second sealing portion and a second pumping chamber portion; the first stator component and the second stator component are configured to be sealingly connected to each other when the first sealing portion abuts against the second sealing portion, thereby defining one or more pumping chambers, each of the one or more pumping chambers being defined by the first pumping chamber portion and the second pumping chamber portion; the first sealing portion and the second sealing portion are uncoated surface portions formed of the first material; and the first pumping chamber portion and the second pumping chamber portion are coated with a second material, the second material being different from the first material. Attached Figure Description
[0018] The present invention will now be described by way of example only with reference to the accompanying drawings, in which: Figure 1 This is a schematic diagram (not to scale) showing the housing of the vacuum pump; Figure 2 This is a schematic diagram (not to scale) illustrating the vacuum pump. Figure 3 This is a schematic illustration (not to scale) showing further details of the stator components; Figure 4 and Figure 5 This is a schematic illustration (not to scale) showing further details of the insulation panel; and Figure 6 This is a process flow diagram illustrating certain steps of a method for assembling or supplying a vacuum pump stator. Detailed Implementation
[0019] Figure 1 The diagram (not to scale) illustrates a schematic representation of one embodiment of a vacuum pump housing 100. The housing 100 includes a stator comprising a pair of shell-type stators, hereinafter referred to as a first stator component 101 and a second stator component 102. The housing also includes a pair of end plates or heat insulation plates, hereinafter referred to as a first heat insulation plate 103 and a second heat insulation plate 104.
[0020] The first stator component 101 has a first surface 106, in Figure 1 In the orientation, the first surface 106 is the lower surface of the first stator component 101 facing the second stator component 102. The first surface 106 includes a plurality of first grooves 108 defined therein.
[0021] The second stator component 102 has a second surface 110, in Figure 1 In the orientation, the second surface 110 is the upper surface of the second stator component 102 facing the first stator component 101. The second surface 110 includes a plurality of second grooves 112 defined therein.
[0022] The first groove 108 and the second groove 112, defined by the first stator component 101 and the second stator component 102 respectively, are configured to receive the rotating component of the vacuum pump, i.e., the rotor of the vacuum pump.
[0023] The first stator component 101 and the second stator component 102 are brought together (e.g.) Figure 1 (As indicated by middle arrows 118 and 120) to hold the rotating components in the first groove 108 and the second groove 112. Then, heat insulation plates 103 and 104 are brought in to hold the stator components 101 and 102 (as shown by...). Figure 1 (As indicated by the middle arrows 114 and 116).
[0024] Figure 2 This is a schematic diagram (not to scale) showing a vacuum pump 200 including the housing 100.
[0025] In this embodiment, the first stator component 101 and the second stator component 102 are hermetically connected to each other such that at least a portion of the first surface 106 abuts (i.e., contacts) with at least a portion of the second surface 110. In this embodiment, the first groove 108 and the second groove 112 are aligned, thereby defining a plurality of pumping chambers 202 between the first stator component 101 and the second stator component 102. The pumping chambers 202 are collectively referred to as the swept volume of the vacuum pump 200. Each of the plurality of pumping chambers 202 is at least partially defined by a corresponding pair of the first groove 108 and the second groove 112.
[0026] A pair of cooperating rotor assemblies, hereinafter referred to as first rotor assembly 204 and second rotor assembly 206, are mounted in vacuum pump 200. First rotor assembly 204 includes a first plurality of vacuum pump rotors 208 mounted on a first shaft 210. Second rotor assembly 206 includes a second plurality of vacuum pump rotors 212 mounted on a second shaft 214. The first plurality of vacuum pump rotors 208 and the second plurality of vacuum pump rotors 212 are arranged in a cooperating pair of rotors 208, 212. Each pair of cooperating rotors 208, 212 is located within a corresponding pumping chamber 202.
[0027] In this embodiment, to adequately seal the first stator component 101 and the second stator component 102 together, one or more (e.g., two) longitudinal seals are positioned along the mating surfaces (i.e., the first surface 106 and the second surface 110) of the stator components 101, 102. Furthermore, to ensure adequate sealing between the stator components 101, 102 and the heat insulation plates 103, 104, a pair of seals defining a closed shape (e.g., annular seals in some embodiments) are positioned between the heat insulation plates 103, 104 and the stator components 101, 102. The seals may be elastomeric seals.
[0028] Figure 3 This is a schematic illustration (not to scale) showing further details of the second stator component 102. Those skilled in the art will understand that the first stator component 101 may have a similar or identical construction to the second stator component 102.
[0029] The second stator component 102 includes a body of a first material. The second stator component 102 is formed from the first material, for example by one or more processes selected from the group consisting of casting, molding, machining, and additive manufacturing (AM).
[0030] In this embodiment, the first material is spheroidal graphite (SG) iron.
[0031] The second surface 110, that is, the mating surface of the second stator component 102 that abuts against the first surface 106 of the first stator component 101 to seal, defines two parts, hereinafter referred to as the first surface portion 301 and the second surface portion 302.
[0032] The first surface portion 301 in Figure 3 The second surface portion 302 is shown without a shaded line (i.e., without shading). Figure 3 It is shown in the middle as a shaded line (i.e., with a shadow).
[0033] The first surface portion 301 is a portion of the second surface 110 such that the first stator component 101 and the second stator component 102 are sealed to each other when the first surface 106 is positioned against or in contact with the second surface 110 (e.g., Figure 2 As shown and described in more detail above, the portion partially defines the one or more pumping chambers 202. In this embodiment, the first surface portion 301 is defined by the second groove 112. In other words, the first surface portion 301 is a groove portion of the second surface 110.
[0034] In this embodiment, the first surface portion 301 is a portion of the second surface 110 in which one or more of the rotor assemblies 204, 206 move or pass over during use (i.e., when the vacuum pump 200 is operating). The first surface portion 301 is also a portion of the second surface 110 in which, during use (i.e., when the vacuum pump 200 is operating), the portion tends to be exposed to relatively high flow rates or velocities of process gas pumped by the vacuum pump 200.
[0035] In this embodiment, the first surface portion 301 is the uncoated portion of the second surface 110. In other words, no material coating is applied to the first surface portion 301. Therefore, the first surface portion 301 is a surface formed of the first material, which in this embodiment is SG iron.
[0036] The second surface portion 302 is a portion of the second surface 110 such that the first stator component 101 and the second stator component 102 are sealed to each other when the first surface 106 is positioned against or abuts the second surface 110 (e.g., Figure 2 As shown and described in more detail above, the portion does not limit the one or more pumping chambers 202. In this embodiment, the second surface portion 302 is the portion of the second surface that engages with a corresponding portion of the first surface 106 (i.e., can be positioned against a corresponding portion of the first surface 106 or can abut or seal against a corresponding portion of the first surface 106). In other words, the second surface portion 302 may be a portion of the second surface 110 that is not the second groove 112.
[0037] In this embodiment, the second surface portion 302 is a portion of the second surface 110 in which neither of the rotor assemblies 204, 206 moves or crosses during use (i.e., when the vacuum pump 200 is running). The second surface portion 302 is also a portion of the second surface 110 in which, during use (i.e., when the vacuum pump 200 is running), the portion is preferably not exposed to the process gas, or is only exposed to stagnant or relatively low flow rates or velocities of the process gas.
[0038] In this embodiment, the second surface portion 302 is a plated portion of the second surface 110. In other words, the second portion 302 is plated with a second material different from the first material.
[0039] In this embodiment, one or more grooves on the second surface portion 302 for receiving longitudinal seals for sealing the mating surfaces (i.e., the first surface 106 and the second surface 110) of the stator components 101, 102 may be coated with the second material.
[0040] In this embodiment, the end 304 of the second stator component 102 (i.e., the end surface against which the heat insulation plates 103, 104 are positioned during use) may also be coated with the second material. The end 304 defines a surface that does not define the one or more pumping chambers 202. Furthermore, during use (i.e., when the vacuum pump 200 is running), neither of the rotor assemblies 204, 206 moves on or across the end 304. During use (i.e., when the vacuum pump 200 is running), the end 304 tends to be unexposed to the process gas, or only exposed to stagnant or relatively low flow rates or velocities of the process gas.
[0041] In this embodiment, the outer surface 306 of the second stator component 102 relative to the pumping chamber 202 may also be coated with the second material. The outer surface 306 defines a surface that does not define the one or more pumping chambers 202. Furthermore, in use (i.e., when the vacuum pump 200 is running), neither of the rotor assemblies 204, 206 moves on or across the outer surface 306. In use (i.e., when the vacuum pump 200 is running), the outer surface 306 tends to be unexposed to the process gas, or only exposed to stagnant or relatively low flow rates or velocities of the process gas.
[0042] In this embodiment, the second material plated on the second portion 302 is a nickel-phosphorus (NiP) alloy. Electroless NiP plating may be applicable. The thickness of the plating applied to the second portion may depend on the application and may, for example, range from about 10 µm to about 100 µm, or more preferably from about 10 µm to about 50 µm, or even more preferably from about 10 µm to about 30 µm. More preferably, the thickness of the plating is about 25 µm.
[0043] Those skilled in the art will understand that the first stator component 101 has a structure corresponding to that described above for the second stator component 102. The first stator component 101 may be similar to or the same as the second stator component 102.
[0044] More specifically, similar to the second surface 110, the first surface 106 defines two portions.
[0045] The first surface portion of the first surface 106 is such that the first stator component 101 and the second stator component 102 are sealed to each other when the first surface 106 is positioned against or in contact with the second surface 110 (e.g., Figure 2 As shown and described in more detail above, the portion partially defines the one or more pumping chambers 202. In this embodiment, the first surface portion is defined by the first groove 108.
[0046] In this embodiment, the first surface portion of the first surface 106 is a portion over which one or more rotor assemblies 204, 206 move or pass during use (i.e., when the vacuum pump 200 is operating). The first surface portion of the first surface 106 is also a portion over which, during use (i.e., when the vacuum pump 200 is operating), it tends to be exposed to relatively high flow rates or velocities of process gas pumped by the vacuum pump 200.
[0047] In this embodiment, the first surface portion of the first surface 106 is an uncoated portion. In other words, no material coating is applied to the first surface portion of the first surface 106. Therefore, the first surface portion of the first surface 106 is a surface formed of the first material, which in this embodiment is SG iron.
[0048] The second surface portion of the first surface 106 is such that the first stator component 101 and the second stator component 102 are sealed to each other when the first surface 106 is positioned against or in contact with the second surface 110 (e.g., Figure 2 As shown and described in more detail above, the portion does not limit the one or more pumping chambers 202. In this embodiment, the second surface portion of the first surface 106 is a portion that engages with a corresponding portion of the second surface 110 (i.e., can be positioned against a corresponding portion of the second surface 110 or can abut or seal against a corresponding portion of the second surface 110). In other words, the second surface portion of the first surface 106 can be a portion that is not the first groove 108.
[0049] In this embodiment, the second surface portion of the first surface 106 is such that, during use (i.e., when the vacuum pump 200 is running), neither of the rotor assemblies 204, 206 moves on or crosses this portion. The second surface portion of the first surface 106 is also such that, during use (i.e., when the vacuum pump 200 is running), this portion tends to be unexposed to the process gas, or only exposed to stagnant or relatively low flow rates or velocities of the process gas.
[0050] In this embodiment, the second surface portion of the first surface 106 is a plated portion. In other words, the second portion of the first surface 106 is plated with the second material in a manner similar to or the same as the second surface portion 302 of the second surface 110. In this embodiment, one or more grooves located on the second surface portion of the first surface 106 for receiving longitudinal seals for sealing the mating surfaces (i.e., the first surface 106 and the second surface 110) of the stator components 101, 102 may be coated with the second material.
[0051] Figure 4 This is a schematic illustration (not to scale) showing further details of the first heat insulation panel 103. Those skilled in the art will understand that the second heat insulation panel 104 may have a similar or identical construction to the first heat insulation panel 103.
[0052] The first heat insulation panel 103 comprises a body of a first material. The first heat insulation panel 103 is formed from the first material, for example, by one or more processes selected from the group consisting of casting, molding, machining, and additive manufacturing.
[0053] The first heat insulation plate 103 includes a mating surface 400, which can be coupled to the head plate of the vacuum pump in use. In this embodiment, the mating surface 400 defines two portions, hereinafter referred to as a first surface portion 401 and a second surface portion 402.
[0054] The first surface portion 401 in Figure 4 The second surface portion 402 is shown without a shaded line (i.e., without shading). Figure 4 It is shown in the middle as a shaded line (i.e., with a shadow).
[0055] The first surface portion 401 is a portion of the mating surface 400 such that, in use (i.e. when the vacuum pump 200 is running), one or more moving parts of the vacuum pump can move on or across this portion.
[0056] In this embodiment, the first surface portion 401 is the unplated portion of the mating surface 400. In other words, no material coating is applied to the first surface portion 401. Therefore, the first surface portion 401 is a surface formed of the first material, which in this embodiment is SG iron.
[0057] The second surface portion 402 is a portion of the mating surface 400 in which, during use (i.e., when the vacuum pump 200 is running), the moving parts of the vacuum pump do not move on or across this portion. The second surface portion 402 is also a portion of the mating surface 400 in which, during use (i.e., when the vacuum pump 200 is running), this portion tends to be unexposed to the process gas, or only exposed to stagnant or relatively low flow rates or velocities of the process gas.
[0058] In this embodiment, the second surface portion 402 is a plated portion of the bonding surface 400. In other words, the second portion 402 is plated with the second material, which in this embodiment is a NiP alloy.
[0059] In this embodiment, one or more grooves 404 on the second surface portion 402 for receiving a closed-shape seal for sealing the mating surface 400 to the headplate may be coated with the second material.
[0060] Figure 5 This is a schematic illustration (not to scale) showing further details of the first heat insulation panel 103. Specifically, Figure 5 The first heat insulation plate 103 is shown with Figure 4 The side opposite to the side shown and described in more detail above.
[0061] The first heat insulation plate 103 includes a mating surface 500 that seals against the end of the stator formed by the first stator component 101 and the second stator component 102. In this embodiment, the mating surface 500 defines two portions, hereinafter referred to as a first surface portion 501 and a second surface portion 502.
[0062] The first surface portion 501 in Figure 5 The second surface portion 502 is shown without a shaded line (i.e., without shading). Figure 5 It is shown in the middle as a shaded line (i.e., with a shadow).
[0063] The first surface portion 501 is a portion of the mating surface 500 in which one or more of the rotor assemblies 204, 206 move or cross during use (i.e., when the vacuum pump 200 is running). Specifically, in this embodiment, rotors 208, 212 are movable on the first surface portion 501.
[0064] In this embodiment, the first surface portion 501 is the unplated portion of the mating surface 500. In other words, no material coating is applied to the first surface portion 501. Therefore, the first surface portion 501 is a surface formed of the first material, which in this embodiment is SG iron.
[0065] The second surface portion 502 is a portion of the mating surface 500 in which, during use (i.e., when the vacuum pump 200 is running), the moving parts of the vacuum pump do not move on or across this portion. The second surface portion 502 is also a portion of the mating surface 500 in which, during use (i.e., when the vacuum pump 200 is running), this portion tends to be unexposed to the process gas, or only exposed to stagnant or relatively low flow rates or velocities of the process gas.
[0066] In this embodiment, the second surface portion 502 is a plated portion of the bonding surface 500. In other words, the second portion 502 is plated with the second material, which in this embodiment is a NiP alloy.
[0067] In some embodiments, the mating surface 500 may include one or more grooves for receiving closed-shape seals for sealing the mating surface 500 to the end surfaces of the stator components 101, 102. These grooves may be coated with the second material.
[0068] Figure 6 This is a process flow diagram illustrating certain steps of a method 600 for assembling or providing a vacuum pump stator, such as a reference numeral. Figure 2 The vacuum pump stator described in more detail above.
[0069] At step s601, the first stator component 101 is provided. The first stator component 101 has a first surface 106. The body of the first stator component 101 is formed of a first material, such as SG iron.
[0070] At step s602, the second stator component 102 is provided. The second stator component 102 has a second surface 110. The body of the second stator component 102 is formed of the first material.
[0071] At least one of the first surface or the second surface includes one or more grooves. For example, the first surface 106 and the second surface 110 may include corresponding multiple grooves, namely the first groove 108 and the second groove 112.
[0072] The first stator component 101 and the second stator component 102 are configured to be hermetically connected to each other with at least a portion of the first surface 106 abutting against at least a portion of the second surface 110, thereby defining the one or more pumping chambers 202. Each of the one or more pumping chambers 202 is defined at least in part by a corresponding recess of the one or more recesses, for example by a corresponding pair of the first recess 108 and the second recess 112.
[0073] At step s603, each of the first surface 106 and the second surface 110 is plated with a second material (e.g., a NiP alloy) such that the corresponding portions do not define the one or more pumping chambers 202 when the first stator component 101 and the second stator component 102 are sealed to each other with at least a portion of the first surface 106 abutting against at least a portion of the second surface 110. The second material differs from the first material. Any suitable plating process may be performed.
[0074] In some embodiments, the respective portions of each of the first surface 106 and the second surface 110 coated with the second material include (e.g., composed of) those portions that are engaged (e.g., in contact) when the first stator component 101 and the second stator component 102 are hermetically connected together.
[0075] The plating process in step s603 is performed such that corresponding portions of each of the first surface 106 and the second surface 110 are maintained in an unplated state when the first stator component 101 and the second stator component 102 are sealed to each other with at least a portion of the first surface 106 abutting at least a portion of the second surface 110, and the corresponding portions at least partially define the one or more pumping chambers 202 (e.g., at least the first recess 108 and the second recess 112). Therefore, the portions of the first surface 106 and the second surface 110 on which the rotor assembly moves in use are maintained in the unplated state during the plating process by, for example, shielding those surface portions. In this embodiment, the unplated surface portions are formed of the first material, i.e., SG iron.
[0076] Therefore, a method 600 for assembling or providing a vacuum pump stator is provided.
[0077] Seals in vacuum pumps, such as the seals between the shell and stator and between the stator and the insulation plate, tend to be important for achieving good pump performance. In conventional pumps, the performance of the seals, and therefore the pump performance, can be degraded by chemical reactions between the stator and / or gaskets and the pumped process gas. High-temperature process gases can cause, for example, deterioration of the sealing surfaces of the shell stator (i.e., the mating surfaces of the SG iron). Advantageously, the plating on the mating surfaces tends to reduce or eliminate the deterioration of the mating surfaces caused by chemical reactions with the pumped process gas. Specifically, the NiP alloy plating on the abutting portion of the mating surfaces tends to protect the underlying SG iron surface and reduce its deterioration.
[0078] Furthermore, the inventors have recognized that elastomeric seals in direct contact with the SG stator can lead to the formation of iron oxides, for example, under high-temperature conditions. This iron oxide formation can cause gas leakage from the stator. Advantageously, a NiP coating on the sealing surface tends to reduce or eliminate this iron oxide formation.
[0079] Mechanical stability is important for the efficiency and normal operation of vacuum pumps. During operation, metal-to-metal contact may occur between the rotor and stator due to the small gap between them. When this contact does occur, the material properties of the contact surfaces are a significant factor in whether it adversely affects pump operation. Peeling, flaking, and wear of the contact surfaces can lead to complete machine failure. Advantageously, avoiding coating the surfaces of the stator that define the pumping chamber (i.e., the surfaces on which the rotor assembly moves or crosses during use) eliminates the risk of any coating peeling. Furthermore, by not coating these surfaces, the gap between the stator and the moving rotor assembly tends to be maintained, or at least not significantly reduced.
[0080] When metal-to-metal contact occurs between the rotor and stator, the graphite on the surface of the SG stator tends to act as a lubricant between them. If these stator surfaces are coated, this lubrication effect tends not to occur, which can lead to increased wear and reduced pumping performance. Avoiding coating the stator in the rotating areas / pumping chambers tends to provide this lubrication effect.
[0081] Furthermore, using SG iron as a substrate for electroless NiP plating may result in porosity in the NiP plating structure. This porosity can be problematic in areas with fast or turbulent process gas flow (such as pump chambers) and may lead to increased peeling or wear of the NiP plating in those areas. Advantageously, these effects tend to be reduced or eliminated by avoiding NiP plating on the surfaces of the stator that define the pump chambers. Moreover, the inventors have recognized that this porosity of the NiP plating tends not to be a problem in slower / no-flow areas of the pump (such as at sealing surfaces).
[0082] Advantageously, the aforementioned vacuum pump stator tends to provide both improved sealing and mechanical stability.
[0083] In the above embodiments, the vacuum pump is a multi-stage positive displacement pump that employs meshing rotors in each of a plurality of pumping chambers. The rotors may have the same type of profile in each chamber, or the profile may vary from one chamber to another. However, in other embodiments, the vacuum pump is of a different type.
[0084] In the above embodiments, a first surface of the first stator component includes a plurality of first grooves, and a second surface of the second stator component includes a plurality of second grooves. The first and second grooves together define a plurality of pumping chambers. However, in other embodiments, one or both of the first and second surfaces include a different number of grooves than those described above and shown in the figures. For example, in some embodiments, one or both of the first and second surfaces include only a single groove, thereby defining only a single pumping chamber. In some embodiments, the first and second surfaces may include a different number of grooves from each other. In some embodiments, one of the first or second surfaces does not include any pumping chamber grooves, and the pumping chamber is defined by a flat surface of either the first or second surface and one or more grooves on the other surface.
[0085] In the above embodiments, the first material is SG iron. However, in other embodiments, the first material is a different material. Examples of suitable alternative materials include, but are not limited to, FG (flake graphite) iron (such as flake graphite cast iron), NR (nickel iron), and aluminum.
[0086] In the above embodiments, the first material is a NiP alloy. However, in other embodiments, the second material is a different material and / or has a different structure. Examples of suitable alternative coating structures include, but are not limited to, multilayer coatings, such as those comprising NiP and a solid lubricant.
[0087] In some embodiments, the first surface is an unplated portion formed of a first material such that when a first stator component and a second stator component are sealed to each other with at least a portion of the first surface abutting against at least a portion of the second surface, the integral at least partially defines one or more pumping chambers.
[0088] In some embodiments, the first surface is integrally coated with a second material such that when the first stator component and the second stator component are sealed to each other with at least a portion of the first surface abutting at least a portion of the second surface, the integral does not define one or more pumping chambers.
[0089] In some embodiments, the second surface is an unplated portion formed of a first material such that when the first stator component and the second stator component are sealed to each other with at least a portion of the first surface abutting against at least a portion of the second surface, the integral at least partially defines one or more pumping chambers.
[0090] In some embodiments, the second surface is integrally coated with a second material such that when the first stator component and the second stator component are sealed to each other with at least a portion of the first surface abutting at least a portion of the second surface, the integral does not define one or more pumping chambers.
[0091] Although illustrative embodiments of the invention have been disclosed in detail herein with reference to the accompanying drawings, it should be understood that the invention is not limited to the precise embodiments, and that various changes and modifications can be made therein without departing from the scope of the invention as defined by the appended claims and their equivalents.
[0092] List of reference numerals 100 – Housing 101 – First Stator Component 102 – Second stator component 103 – First Insulation Board 104 – Second Insulation Panel 106 – First Surface 108 – First Groove 110 – Second Surface 112 – Second Groove 114, 116, 118, 120 – Arrows indicating the direction of movement. 200 – Vacuum Pump 202 – Pumping Chamber 204 – First Rotor Assembly 206 – Second Rotor Assembly 208 – First Rotor 210 – First Axis 212 – Second Rotor 214 – Second Axis 301 – First Surface Section 302 – Second Surface Section 304 – End 306 – Outer Surface 400 – Joint Surface 401 – First surface portion of mating surface 400 402 – Second surface portion of mating surface 400 404 – Sealing Groove 500 – Joint Surface 501 – First surface portion of mating surface 500 502 – Second surface portion of mating surface 500 600 – Method s601-s603 – Methods and Steps.
Claims
1. A vacuum pump stator, comprising: A first stator component, the first stator component having a first surface; as well as The second stator component has a second surface; wherein... At least one of the first surface or the second surface includes one or more grooves; The first stator component and the second stator component are configured to be hermetically connected to each other with at least a portion of the first surface abutting against at least a portion of the second surface, thereby defining one or more pumping chambers between the first stator component and the second stator component, each of the one or more pumping chambers being defined at least partially by a corresponding recess of the one or more recesses; The first stator component and the second stator component are formed of a first material; At least a portion of each of the first and second surfaces is an unplated portion formed of the first material, wherein when the first stator component and the second stator component are sealed to each other with at least a portion of the first surface abutting at least a portion of the second surface, the at least a portion at least partially defines the one or more pumping chambers; and Each of the first surface and the second surface includes at least a portion thereof, wherein when the first stator component and the second stator component are sealed to each other with at least a portion of the first surface abutting against at least a portion of the second surface, the at least a portion of the one or more pumping chambers is not limited to being coated with a second material, the second material being different from the first material.
2. The vacuum pump stator according to claim 1, wherein, The first material is spheroidal graphite (SG) iron.
3. The vacuum pump stator according to any one of the preceding claims, wherein, The second material is a nickel-phosphorus (NiP) alloy.
4. The vacuum pump stator according to any one of the preceding claims, wherein, The first surface is an unplated portion formed of the first material such that when the first stator component and the second stator component are sealed to each other with at least a portion of the first surface abutting at least a portion of the second surface, the whole at least partially defines the one or more pumping chambers.
5. The vacuum pump stator according to any one of the preceding claims, wherein, The first surface is integrally coated with the second material such that when the first stator component and the second stator component are sealed to each other with at least a portion of the first surface abutting at least a portion of the second surface, the integral does not define the one or more pumping chambers.
6. The vacuum pump stator according to any one of the preceding claims, wherein, The second surface is an unplated portion formed of the first material such that when the first stator component and the second stator component are sealed to each other with at least a portion of the first surface abutting at least a portion of the second surface, the entirety at least partially defines the one or more pumping chambers.
7. The vacuum pump stator according to any one of the preceding claims, wherein, The second surface is integrally coated with the second material such that when the first stator component and the second stator component are sealed to each other with at least a portion of the first surface abutting at least a portion of the second surface, the integral does not define the one or more pumping chambers.
8. The vacuum pump stator according to any one of the preceding claims, wherein: The first stator component and the second stator component include corresponding ends, which are arranged to receive a vacuum pump heat shield when the first stator component and the second stator component are sealed to each other with at least a portion of the first surface abutting against at least a portion of the second surface. and At least a portion of each of the ends is coated with the second material.
9. A vacuum pump, comprising: A vacuum pump stator according to any one of the preceding claims, wherein the first stator component and the second stator component are hermetically connected to each other with at least a portion of the first surface abutting against at least a portion of the second surface, thereby defining the one or more pumping chambers between the first stator component and the second stator component; and One or more rotors are arranged to rotate within one or more pumping chambers.
10. The vacuum pump of claim 9, further comprising one or more sealing devices disposed between the at least portion of the first surface and the at least portion of the second surface.
11. The vacuum pump according to claim 9 or 10, wherein: The vacuum pump stator is the vacuum pump stator according to claim 8; and The vacuum pump includes one or more vacuum pump insulation plates, each vacuum pump insulation plate being hermetically attached to a corresponding end of the vacuum pump stator.
12. A method for forming a vacuum pump stator, the method comprising: A first stator component is provided, the first stator component having a first surface, the first stator component being formed of a first material; as well as A second stator component is provided, the second stator component having a second surface, the second stator component being formed of the first material; wherein, At least one of the first surface or the second surface includes one or more grooves; The first stator component and the second stator component are configured to be sealingly connected to each other with at least a portion of the first surface abutting against at least a portion of the second surface, thereby defining one or more pumping chambers, each of the one or more pumping chambers being at least partially defined by a corresponding recess of the one or more recesses; and The method further includes: The second material is used to plate at least a portion of each of the first and second surfaces such that, when the first stator component and the second stator component are sealed to each other with at least a portion of the first surface abutting at least a portion of the second surface, the at least a portion does not define the one or more pumping chambers, and the second material is different from the first material; and Each of the first and second surfaces is kept unplated if at least a portion thereof defines at least part of the one or more pumping chambers when the first stator component and the second stator component are sealed to each other with at least a portion of the first surface abutting against at least a portion of the second surface.
13. The method according to claim 12, wherein, The maintenance includes: during the plating process, shielding each of the first and second surfaces with at least a portion thereof, wherein the at least a portion at least partially defines the one or more pumping chambers when the first stator component and the second stator component are sealed to each other with at least a portion of the first surface abutting against at least a portion of the second surface.
14. A vacuum pump stator, comprising: A first stator component, the first stator component having a first surface; as well as The second stator component has a second surface; wherein... At least one of the first surface or the second surface includes one or more grooves; The first stator component and the second stator component are configured to be hermetically connected to each other with at least a portion of the first surface abutting against at least a portion of the second surface, thereby defining one or more pumping chambers, each of the one or more pumping chambers being defined at least in part by a corresponding recess of the one or more recesses; The first stator component and the second stator component are formed of a first material; The first surface includes: A first surface portion, which at least partially defines the one or more pumping chambers when the first stator component and the second stator component are sealingly connected to each other with at least a portion of the first surface abutting against at least a portion of the second surface, the first surface portion being an uncoated surface portion formed of the first material; and The second surface portion, when the first stator component and the second stator component are sealingly connected to each other with at least a portion of the first surface abutting against at least a portion of the second surface, does not define the one or more pumping chambers, and the second surface portion is coated with a second material different from the first material; and The second surface includes: A third surface portion, which at least partially defines the one or more pumping chambers when the first stator component and the second stator component are sealingly connected to each other with at least a portion of the first surface abutting against at least a portion of the second surface, the third surface portion being an uncoated surface portion formed of the first material; and The fourth surface portion, which does not define the one or more pumping chambers, is coated with the second material when the first stator component and the second stator component are sealed to each other with at least a portion of the first surface abutting against at least a portion of the second surface.
15. A vacuum pump stator, comprising: A first stator component, the first stator component having a first mating surface; as well as The second stator component has a second mating surface; wherein... The first stator component and the second stator component are formed of a first material; The first mating surface includes a first sealing portion and a first pumping chamber portion; The second mating surface includes a second sealing portion and a second pumping chamber portion; The first stator component and the second stator component are configured to be hermetically connected to each other when the first sealing portion abuts against the second sealing portion, thereby defining one or more pumping chambers, each of the one or more pumping chambers being defined by the first pumping chamber portion and the second pumping chamber portion; The first sealing portion and the second sealing portion are uncoated surface portions formed from the first material; and The first pumping chamber portion and the second pumping chamber portion are coated with a second material, which is different from the first material.