Pump and method for generating a sliding layer

Abstract

The invention relates to a pump, in particular a vacuum pump, comprising a sliding layer, wherein the sliding layer comprises an oxide layer, in particular formed by anodic oxidation in an acidic electrolyte, and a polymer-based sealant, in particular based on a fluoropolymer, and wherein the oxide layer is at least partially covered and / or impregnated by the sealant. Furthermore, the invention relates to a method for producing a sliding layer, comprising the following steps: a) producing an oxide layer, in particular by anodic oxidation, in an electrolyte, preferably comprising oxalic acid; and b) coating the oxide layer with a sealant.

Description

Technical Field

[0001] This invention relates to a pump, particularly a vacuum pump, comprising, for example, at least two conveying elements movable relative to each other and at least one seal disposed on one of the two conveying elements. According to the invention, a sliding layer is provided, which is applied at least partially to, particularly at least one, conveying element. Furthermore, the invention relates to the use of the component with the sliding layer and at least one seal in the manufacture of a pump, particularly a vacuum pump, and to a method for generating the sliding layer. Background Technology

[0002] Fluids such as grease or oil are commonly used to seal the delivery chamber of pumps, especially vacuum pumps. For example, piston pumps essentially have a gap between the delivery chamber and the piston. In fluid-sealed or fluid-lubricated designs, this gap is filled with a fluid (usually oil or grease) during pump operation, which acts as a sealant between the piston and the delivery chamber. Furthermore, surface structural defects (cracks, holes, pores, etc.) can exhibit cleavage effects (spaltwirksam). This is particularly true for defects in certain coatings (paints, anodized layers, etc.). A disadvantage of such pumps is that the medium being pumped, such as gas or vapor, can react with the fluid used as a sealant, which particularly reduces the sealing effect. Another problem, especially in the case of vacuum pumps, is that the container can become contaminated by the fluid used.

[0003] For this reason, especially for vacuum pumps, so-called dry-flow pumps are preferred, where the medium being pumped does not come into contact with a fluid. Sliding or friction sealants made of chemically resistant materials (usually plastics) are typically used here. For example, in the case of piston pumps, this sealant is usually applied to the piston. During operation, the sealant rubs against the inner wall of the cylinder to seal the resulting delivery space as airtight as possible. Another example of a pump that is also typically dry-flow pumps (i.e., without fluid lubricant) is a scroll pump or screw pump. A scroll pump has a sickle-shaped suction chamber formed by the engagement of a rotor with a helical cross-section and a similarly helical stator, where the rotor moves in an orbital motion via an eccentric drive. A sealant is applied to the helical end faces to seal the delivery chamber, and the rotor end face sealant rubs against the stator, and vice versa.

[0004] The disadvantage of these sliding or friction sealants is that they typically suffer very severe wear due to continuous sliding friction and generally have only a limited service life. In particular, the sealant in the intake chamber may wear away as dust after a period of operation. With increased wear, the sealing effect of the worn sealant decreases, which can lead to poor end pressure.

[0005] Slip or protective layers can be incorporated to reduce wear, as described, for example, in EP 3 153 706 A1. Such slip layers can be incorporated into acidic electrolytes, particularly those containing oxalic acid, sulfuric acid, or mixtures thereof, as oxide layers formed by anodizing. These slip / protective layers also increase the substrate's corrosion and abrasion resistance. A very narrow gap (a few 0.01 mm) exists between the sickle-shaped suction chambers. Harte slip and protective layers ensure a longer service life for the substrate in the event of contact or penetration of solid objects between the two components forming the suction chambers. However, it has been found that such oxide layers, due to their porous structure, cannot achieve the required final pressure and airtightness, or only after a long operating time (the so-called break-in period). Although tests have shown that, particularly for newly coated components, a heating process of the coated component can reduce break-in time or increase final pressure, improvements in achievable final pressure and reductions in break-in time are still needed. Summary of the Invention

[0006] Therefore, the object of the present invention is to provide a pump that overcomes the above-mentioned disadvantages or at least improves upon known solutions.

[0007] The objective is achieved by the pump and method according to the present invention.

[0008] The pump according to the invention is preferably a vacuum pump. The pump includes a sliding layer comprising an oxide layer and a sealant formed of a fluoropolymer, wherein the oxide layer is at least partially covered and / or impregnated by the sealant.

[0009] The sliding layer described herein can possess a variety of properties. Particularly when used in vortex pumps (e.g., vortex vacuum pumps), the sliding layer serves two functions: 1) a sliding layer / optimization for the friction system; 2) a protective layer; protecting the substrate from damage, wear, and corrosion. Tests have shown that without a hard surface coating on the vortex pump, the substrate can be damaged in a very short time.

[0010] The oxide layer is preferably formed by anodic oxidation, particularly in an acidic electrolyte. The electrolyte preferably contains oxalic acid and / or sulfuric acid, with sulfuric acid being more preferred. The oxide layer is preferably an anodic metal oxide formed by the electrolytic oxidation of aluminum. This oxide layer can possess the aforementioned multifunctional properties regarding sliding and protection.

[0011] It has been found that pumps according to the invention, having a sliding layer comprising an oxide layer and a sealant, such as a polyurethane layer or an impregnation, can achieve lower final pressures compared to sliding layers (e.g., as described in EP 3 153 706 A1). The hard oxide layer applied for wear protection has pores, defects, and thermally induced cracks. The pores are primarily arranged perpendicular to the layer, but there are also branches within the layer that are partially arranged horizontally with the layer, which interconnect the vertical pores. In addition to pores, this hard oxide layer has other defects, such as inclusions and cracks. Defects and pores represent microscopic channels through which gas can flow. Furthermore, substances such as water can be discharged from these areas. This reduces airtightness and adversely affects the achievable final pressure. This means that the desired final pressure and airtightness cannot be achieved or can only be achieved after a long period. During the so-called break-in process, pores and defects are essentially closed in their respective locations due to wear of the seals. Furthermore, there is degassing of the sealing medium, such as coating residue. It has been found that sealants can achieve the desired final pressure more quickly while maintaining a high level of wear protection. This can likely be explained by the fact that, in the pump according to the invention, the pores contained in the oxide layer are sealed by the sealant, thus preventing or at least reducing airflow within the sliding layer or degassing of the sliding layer.

[0012] Preferably, the pump, particularly a vacuum pump, further includes at least two delivery elements movable relative to each other, the delivery elements being arranged to interact in a sealing manner to form at least one delivery chamber, with at least one seal disposed on one of the two delivery elements. In this case, a sliding layer is applied at least partially to at least one delivery element and interacts with the corresponding seal.

[0013] According to another preferred embodiment of the invention, the pump is a helical or vortex pump, particularly a helical or vortex vacuum pump, wherein a sliding layer is applied at least partially to at least one helical element.

[0014] A helical or vortex pump, particularly a helical or vortex vacuum pump, is preferably a pump in which the delivery elements are two helical elements movable relative to each other, each helical element having a wall on a carrier that extends helically around an axis and has a free end face, and the walls are arranged to seal each other to form a delivery chamber, wherein a seal is arranged on the free end face of the walls.

[0015] According to another embodiment of the invention, the pump is a piston pump, particularly a piston vacuum pump, having at least one cylinder and a piston, the cylinder having an inner wall, the piston being movable within the cylinder. The delivery element is a cylinder and a piston movable therein, wherein a seal is provided on the piston and / or the inner wall of the cylinder. In this configuration, a sliding layer is applied at least partially to the inner wall of the cylinder and / or the piston.

[0016] Preferably, in the pump of the present invention, the fluoropolymer contained in the sealant is either a fully fluorinated polymer, i.e., a perfluorinated polymer, or a polymer having perfluorinated segments. Sealants containing fluorinated polyurethane, particularly polyurethane with perfluorinated segments, have proven particularly suitable. It has been shown that using such polyurethane with perfluorinated segments can achieve low final pressure and short break-in time while maintaining high abrasion resistance. According to the invention, it is also preferred that the sealant is formed of polyurethane with polyether segments. Polyurethane with polyether segments has also proven particularly suitable in terms of low final pressure, short break-in time, and high abrasion resistance. Therefore, more preferably, the polyurethane layer is formed of polyurethane with perfluorinated polyether segments. Using perfluorinated polyether segments can achieve particularly low final pressure and short break-in time while providing very good abrasion resistance. The perfluorinated polyether segments can be present in the dispersion used to produce the sealant as a polyol prepolymer or a diisocyanate prepolymer. The perfluorinated polyether segments can be, for example, segments based on perfluorinated polyethylene glycol or perfluorinated polypropylene glycol, preferably based on perfluorinated polyethylene glycol. The sliding layer of the pump according to the invention preferably has at least one fluorinated polymer different from PTFE. Due to its particle size and associated relatively high permeability, PTFE is unsuitable as a sealant for porous oxide layers. Therefore, while PTFE may be included, in this case, at least one other polymer different from PTFE should be included.

[0017] In the sliding layer of the pump according to the invention, a sealant, for example in the form of a polyurethane layer, can be obtained by applying a dispersion, such as a polyurethane dispersion, to the oxide layer. The sealant can be applied either as an aqueous dispersion or as a solvent-based dispersion. In the case of a solvent-based dispersion, the solvent is preferably a C1 to C8 alcohol, particularly a C3 to C6 alcohol, such as a C4 alcohol. The sealant can preferably be obtained by applying an aqueous polyurethane dispersion, particularly an aqueous ionic polyurethane dispersion, preferably an anionic polyurethane dispersion. Anionic polyurethane dispersions based on a perfluorinated polyether (PFPE) structure have proven particularly advantageous. Exemplary suitable anionic polyurethane dispersions are available from Solvay under the trade name Fluorolink.

[0018] The dispersion can be applied by spraying, dipping, scraping, or spin coating. Application by spraying or dipping has proven advantageous in terms of ease of implementation, with spraying being particularly advantageous in terms of uniformity and the production of exceptionally thin layers. Scraping or spin coating can also produce very uniform thin coatings. According to a preferred embodiment, the dispersion is applied selectively, particularly to the sealing surface.

[0019] According to the invention, the thickness of the sealant, for example, in the form of a polyurethane layer, is not limited to any particular thickness. However, sealants with a thickness of 0.1 µm to 35 µm have proven advantageous in balancing low final pressure and short break-in time on the one hand, and high abrasion resistance on the other. More preferably, the sealant thickness is 0.5 µm to 25 µm, more preferably 0.8 µm to 20 µm, even more preferably 1.0 µm to 15 µm, and most preferably 1.5 µm to 10 µm. The sealant layer thickness is most preferably less than or equal to 5 µm. Moreover, the sealant can impregnate the pores of the oxide layer without a identifiable continuous fluoropolymer layer covering the oxide layer. Impregnation can fill defects in the pores connecting the oxide layer, thereby increasing airtightness. In the pump according to the invention, preferably, for example, the sealant in the form of a polyurethane layer completely or substantially completely covers the oxide layer. Complete or substantially complete coverage seals the pores contained in the oxide layer, thereby preventing the transported medium from bypassing the sliding layer. In this way, particularly low final pressure can be achieved in a shorter break-in period.

[0020] To improve wear resistance, the sliding layer of the pump according to the invention preferably contains a tackifier. The tackifier is typically a reactive compound that improves the bonding between the sealant, preferably in the form of a polyurethane layer, and the oxide layer. Such tackifiers are known to those skilled in the art. They can be, for example, epoxy compounds, siloxane compounds, aziridine derivatives, melamine compounds, or terminated isocyanate compounds. Epoxysilanes and polyaziridines have proven to be particularly suitable tackifiers. This tackifier can be included in the sealant formed as a polyurethane layer and / or impregnated, for example, by adding them to a polyurethane dispersion used to produce the polyurethane layer. Alternatively or additionally, the tackifier can also be applied to the oxide layer prior to the application of the sealant. In this case, the tackifier acts as a primer on the oxide layer.

[0021] The pump according to the invention preferably comprises a conveying element made of a base material, at least partially made of aluminum or an aluminum alloy, on which a sliding layer is applied. The conveying element is preferably made of aluminum or an aluminum alloy. The base material is particularly preferably an aluminum alloy of the AlMgSi type. Aluminum alloys of the AlMgSiMn, AlMgSiPb, or AlZnMg type are also advantageous. Aluminum and aluminum alloys have proven particularly suitable for anodizing in an acidic electrolyte and forming the sliding layer according to the invention. In this case, the electrolyte preferably contains oxalic acid, sulfuric acid, or a mixture thereof. More preferably, the electrolyte contains sulfuric acid.

[0022] Furthermore, the present invention relates to a method for generating a sliding layer, comprising the following steps:

[0023] a) Preferably, the oxide layer is produced in an acidic electrolyte, particularly by anodic oxidation; and

[0024] b) Apply an oxide layer with a sealant.

[0025] It should be understood that the oxide layer is formed on a substrate in step A, such as the delivery element of a pump as described above.

[0026] The pores and defects contained in the oxide layer are preferably sealed by the sealant in step b). This creates a sliding layer, which prevents cross-connections between pores and defects in the oxide layer, thereby improving airtightness. The sealant used in the method according to the invention is particularly as described above regarding the pump according to the invention.

[0027] The method according to the invention is preferably part of the production process of pumps, particularly vacuum pumps, as described herein.

[0028] It goes without saying that various aspects of the present invention, including those described below with reference to the accompanying drawings, can be advantageously combined with each other. Attached Figure Description

[0029] The invention is explained below by way of example only, with reference to schematic symbols and embodiments.

[0030] Figure 1 A cross-sectional view of the vortex pump is shown.

[0031] Figure 2 The housing of the electronic components of the vortex pump is shown.

[0032] Figure 3 A perspective view of a vortex pump is shown, revealing selected components.

[0033] Figure 4 The pressure sensor integrated into the pump is shown.

[0034] Figure 5 The movable screw component of the pump is shown.

[0035] Figure 6 Showing with Figure 5 The spiral component on one side is visible on the other side.

[0036] Figure 7 A clamping device for the spiral component is shown.

[0037] Figure 8 and Figure 9 Eccentric shafts with balancing counterweights for different vortex pumps are shown respectively.

[0038] Figure 10 A perspective view of a gas ballast ventil with an actuation handle is shown.

[0039] Figure 11 Show Figure 10 A cross-sectional view of the valve.

[0040] Figure 12 Show Figure 5 and Figure 6 Part of the spiral component.

[0041] Figure 13 The cross-section of the helical component passing through the helical wall in the outer end region is shown.

[0042] Figure 14 Show Figure 1 A perspective view of the air guide shroud of a vortex pump.

[0043] Figure 15 A cross-sectional view of the clamping thread is shown.

[0044] Figure 16 Show Figure 1 Detailed diagram of a spiral pump or vortex pump.

[0045] Figure 17 An electron microscope cross-sectional view of the oxide layer is shown.

[0046] Figure 18 Show Figure 16 A cross-sectional electron microscope image of the oxide layer at a higher magnification.

[0047] Figure 19 Show Figure 16 and Figure 17 Electron microscope planar image of the oxide layer.

[0048] Figure 20 The development of vacuum is shown when using vortex pumps with both coated and uncoated delivery elements. Detailed Implementation

[0049] Although the invention is not limited to the vortex pump 20, it has proven to be very suitable. In principle, the pump according to the invention can also be a piston pump (not shown in the figures). The sealants described herein are also preferred for sealing coated components in general (e.g., static sealing of oxide layers, such as O-ring seals). Figure 1 A vacuum pump designed as a vortex pump 20 is shown. It includes a first housing element 22 and a second housing element 24, wherein the second housing element 24 has a pumping structure, namely a helical wall 26. Therefore, the second housing element 24 forms the fixed helical component of the vortex pump 20. The helical wall 26 interacts with the helical wall 28 of a movable helical element 30, which is eccentrically actuated by an eccentric shaft 32 to produce a pumping action. The gas to be pumped is delivered from an inlet 31 defined in the first housing element 22 to an outlet 33 defined in the second housing element 24.

[0050] The eccentric shaft 32 is driven by a motor 34 and supported by two rolling bearings 36. It includes an eccentric pin 38 arranged eccentrically relative to its axis of rotation, which transmits its eccentric deflection to the movable helical component 30 via another rolling bearing 40. For sealing, in Figure 1 The left end of the bellows 42 is also fixed to the movable helical component 30, and the right end of the bellows is fixed to the first housing element 22. The left end of the bellows 42 deflects with the movable helical component 30.

[0051] The vortex pump 20 includes a fan 44 for generating a cooling airflow. An air guide shroud 46 is provided for this cooling airflow, to which the fan 44 is also attached. The air guide shroud 46 and housing elements 22 and 24 are shaped such that the cooling airflow flows substantially around the entire pump housing, thus achieving good cooling performance.

[0052] The vortex pump 20 also includes an electronic component housing 48, in which control devices and power electronics for driving the motor 34 are arranged. The electronic component housing 48 also forms the base of the pump 20. A channel 50 can be seen between the electronic component housing 48 and the first housing element 22 through which the airflow generated by the fan 44 is guided along the first housing element 22 and also along the electronic component housing 48, effectively cooling both.

[0053] Electronic component housing 48 Figure 2The diagram is shown in more detail below. It comprises multiple individual chambers 52. Electronic components can be encapsulated within these chambers 52 and are thus advantageously shielded. When encapsulating the electronic components, it is preferable to use as little encapsulation material as possible. For example, the encapsulation material can be introduced into the chambers 52 first, and then the electronic components can be pressed in. The chambers 52 can preferably be designed such that different variations of the electronic components, particularly different configuration variations of the circuit board, can be arranged and / or encapsulated within the electronic component housing 48. For some variations, individual chambers 52 can also remain empty, i.e., without electronic components. Thus, a so-called modular system for different types of pumps can be achieved in a simple manner. The encapsulation material can, in particular, be thermally conductive and / or electrically insulating.

[0054] refer to Figure 2 Multiple walls or ribs 54 are designed on the rear side of the electronic component housing 48, defining multiple channels 50 for guiding cooling airflow. The chamber 52 also enables particularly good heat dissipation for the electronic components disposed therein, especially those related to thermally conductive encapsulation materials, as well as the ribs 54. Therefore, the electronic components can be cooled particularly effectively, and their lifespan can be extended.

[0055] exist Figure 3 In the diagram, the vortex pump 20 is shown as a whole in a perspective view, with the air guide shroud 46 concealed, thus the stationary helical component 24 and the fan 44 are particularly visible. A plurality of star-shaped recesses 56 are provided on the stationary helical component 24, each defining a rib 58 arranged between the recesses 56. Cooling airflow generated by the fan 44 passes through the recesses 56 and the ribs 58, thus cooling the stationary helical component 24 particularly effectively. The cooling airflow first flows around the stationary helical component 24 and then around the first housing element 22 or the electronic component housing 48. This arrangement is particularly advantageous because the effective pumping area of ​​the pump 20 generates a large amount of heat during operation due to compression, and thus is cooled first there.

[0056] Pump 20 includes a pressure sensor 60 integrated therein. This pressure sensor is disposed within an air guide shroud 46 and screwed into a retaining screw component 24. Pressure sensor 60 is connected via a cable connection (partially shown) to an electronics housing 48 and a control device disposed therein. In this case, pressure sensor 60 is integrated into the control device of the vortex pump 20. For example, Figure 1 The visible motor 34 can be driven in response to the pressure sensed by the pressure sensor 60. For example, when pump 20 is used as a backing pump for a high vacuum pump in a vacuum system, the high vacuum pump will only be turned on when the pressure sensor 60 measures a sufficiently low pressure. This protects the high vacuum pump from damage.

[0057] Figure 4A cross-sectional view of the pressure sensor 60 and its arrangement on the fixed helical member 24 is shown. A channel 62 is provided for the pressure sensor 60, leading to the non-pumping external region between the helical walls 26 and 28 of the fixed or movable helical members 24 and 30. Therefore, the pressure sensor measures the pump's suction pressure. Alternatively or additionally, the pressure between the helical walls 26 and 28 can also be measured, for example, in the pumping region. Depending on the location of the pressure sensor 60 or the channel 62, intermediate pressures can also be measured, for example.

[0058] The pressure sensor 60 allows for the detection of wear conditions in pumping components, particularly the sealing element 64, also known as the tip seal, specifically by determining compression. Furthermore, the measured suction pressure can also be used to regulate the pump (e.g., pump speed). For example, the suction pressure can be specified via software and set by changing the pump speed. It is also conceivable that, based on the measured pressure, the pressure increase caused by wear can be compensated for by increasing the speed. This means that tip seal replacement can be delayed, or longer replacement intervals can be achieved. Therefore, data from the pressure sensor 60 can generally be used, for example, to determine wear, control the pump as needed, process control, etc.

[0059] For example, pressure sensor 60 may be optionally provided. Instead of pressure sensor 60, a blind plug for closing channel 62 may be provided, for example. Then, if necessary, pressure sensor 60 may be modified, for example. In particular with regard to modification, and generally advantageously, it may be specified that pressure sensor 60 is automatically recognized when it is connected to the control device of pump 20.

[0060] The pressure sensor 60 is positioned within the cooling airflow of the fan 44. This allows it to be advantageously cooled. This also eliminates the need for special measures to ensure the pressure sensor 60 is more temperature-resistant, and therefore allows the use of a more cost-effective sensor.

[0061] In addition, the pressure sensor 60 is specifically arranged so as not to increase the external size of the pump 20, and thus the pump 20 remains compact.

[0062] exist Figure 5 and Figure 6 In the diagram, the movable spiral component 30 is shown in different views. The spiral structure of the spiral wall 28 is... Figure 5 This can be seen particularly clearly in the image. In addition to the spiral wall 28, the spiral component 30 also includes a base plate 66 from which the spiral wall 28 extends.

[0063] It is possible Figure 6 The side of the base plate 66 opposite to the spiral wall 28 is visible. On this side, the base plate specifically includes multiple fixing grooves, for example, for fixing the bearing 40 and the bellows 42, such as... Figure 1 As shown.

[0064] Three retaining protrusions 68 are located on the outer side of the base plate 66, spaced apart and evenly distributed around the circumference of the base plate 66. The retaining protrusions 68 extend radially outward. In particular, all retaining protrusions 68 have the same radial height.

[0065] A first intermediate portion 70 of the circumference of the base plate 66 extends between the two retaining protrusions 68. The first intermediate portion 70 has a greater radial height than the second intermediate portion 72 and the third intermediate portion 74. The first intermediate portion 70 is the outermost 120° portion of the opposing spiral wall 28.

[0066] In the manufacture of the movable spiral component 30, the base plate 66 and the spiral wall 28 are preferably manufactured from solid materials together, that is, the spiral wall 28 and the base plate 66 are formed as a single piece.

[0067] For example, in the case of a finishing operation, the spiral component 30 can be directly clamped onto the retaining protrusion 68. Within the same clamping range, for example, the base plate 66 can also be clamped. Figure 6 The sides shown are machined, in particular, to allow for the introduction of fastening grooves. In principle, the spiral wall 28 can also be machined from a solid material within this clamping range.

[0068] For this purpose, the spiral component 30 can be clamped, for example, by a clamping device 76, such as Figure 7 As shown. It has a hydraulic three-jaw chuck 78 for direct contact with the three retaining protrusions 68. Furthermore, the clamping device 76 has continuous grooves 80 through which the tool can approach the helical component 30, particularly... Figure 6 The spiral component shown is located on one side. Therefore, machining operations can be performed from both sides during clamping, particularly at least one finishing of the spiral wall 28 and the introduction of a fastening groove.

[0069] The contour of the retaining protrusions 68 and the clamping pressure of the clamping device 76 are preferably selected such that the helical component 30 does not undergo critical deformation. Three retaining protrusions 68 are preferably selected so that the external dimension, i.e., the maximum diameter of the helical component 30, does not increase. Therefore, material and machining costs are reduced. The retaining protrusions 68 are specifically designed and / or arranged at angular locations such that they are accessible to the threaded connection of the bellows 42. The number of threaded connection points of the bellows 42 is preferably not equal to the number of retaining protrusions 68 on the movable helical component 30.

[0070] Two balance weights 82 attached Figure 1 An eccentric shaft 32 is used to compensate for imbalances in the erregt system. Figure 1 The area of ​​the 82-weight balance on the right side of the middle is in Figure 8 The image is enlarged in size. The counterweight 82 is bolted to the eccentric shaft 32.

[0071] Figure 9 The image shows similar details of another vortex pump, which preferably belongs to the category of... Figure 1 The pump is from the same series as the 20. Figure 9 The pumps are of particularly different sizes, and therefore require different counterweights 82.

[0072] The dimensions of the eccentric shaft 32, the counterweight 82, and the housing element 22 are designed such that only one specific type of counterweight 82, of the two types shown, can be mounted on the eccentric shaft 32 at the corresponding fastening position shown.

[0073] The dimensions of the counterweight 82 are as follows: Figure 8 and Figure 9 The dimensions of the installation space provided for it should be determined together in order to clearly indicate... Figure 9 The counterweight 82 cannot be mounted on the eccentric shaft 32, and vice versa. It goes without saying that the dimensions given are merely illustrative.

[0074] Therefore, in Figure 8 In the middle, the distance between the fastening hole 84 and the shoulder 86 is 9.7mm. Figure 8 The counterweight 82 is shorter in the corresponding direction, that is, 9mm long, so it can be installed without any problems. Figure 9 The balancing weight 82 has a longitudinal extension of 11 mm, measured from the corresponding fastening hole. Therefore, Figure 9 The 82 counterweight cannot be installed Figure 8 On the eccentric shaft 32, because the shoulder 86 collided with the counterweight 82 during the attempt to install, or because Figure 9 The 82-weight balance cannot be completely matched with Figure 8 The eccentric shaft 32 is in contact. Due to Figure 9 The balancing weight 82 is greater than in both measuring dimensions. Figure 8 The distance between the fastening hole 84 and the shoulder 86 in the shaft also prevents assembly in the opposite direction. Furthermore, Figure 8 The 21.3mm size of the counterweight 82 prevents the correct counterweight 82 from being inverted and thus incorrectly installed.

[0075] exist Figure 9 In the middle, the longitudinal distance between the fastening hole 84 and the housing shoulder 88 is 17.5 mm. When Figure 9 When the eccentric shaft 32 is pushed in, it has an extension length of 21.3 mm. Figure 8 The counterweight 82 may collide with the housing shoulder 88, preventing complete assembly. Incorrect assembly is initially possible but can be reliably detected. Figure 8 The counterweight 82 is torsionally mounted around the axis of the fastening hole 84. Figure 9 When the eccentric shaft 32 is in place, the 21.3mm extension will collide with the shoulder 86, which is only 13.7mm away from the fastening hole 84.

[0076] The counterweight 82, particularly the motor-side counterweight 82, is typically designed to prevent confusion with counterweights of other sizes during assembly and / or maintenance. The counterweight is preferably secured using through bolts. Specifically, similar counterweights for different pump sizes are designed to prevent incorrect installation due to adjacent shoulders on the shaft, the position of the counterweight threads and through holes, and shoulders within the housing.

[0077] exist Figure 10 and Figure 11 The image shows the gas ballast valve 90 of the vortex pump 20. It can also be used in... Figure 3 The pump 20 is shown in the overall view and is arranged on the fixed spiral component 24.

[0078] The gas ballast valve 90 includes an actuating handle 92. It comprises a plastic body 94 and a base element 96, preferably made of stainless steel. The base element 96 includes a continuous orifice 98, which is configured on one side for connecting and introducing ballast gas, and on the other side includes a check valve 100. In the illustration, the orifice 98 is also closed by a plug 102. Instead of the plug 102, a filter may also be provided, for example, wherein the ballast gas is preferably air, and can particularly directly enter the valve 90 through the filter.

[0079] The actuation handle 92 is fastened to the rotatable element 106 of the valve 90 by three fastening screws 104, which are arranged in corresponding holes 108. Figure 11 Only one fastening screw is visible in the selected cross-sectional view. The rotatable element 106 is rotatably fastened to the second housing element 24 by means of a fastening screw (not shown) extending through the hole 110.

[0080] To actuate valve 90, the torque manually applied to the actuation handle 92 is transmitted to the rotatable element 106, causing the rotatable element to rotate. Therefore, the orifice 98 communicates with the interior of the housing. Valve 90 has three switching positions, namely... Figure 10 The diagram shows the blocking position, the right rotation position, and the left rotation position, where hole 98 communicates with different areas inside the housing.

[0081] Holes 108 and 110 are closed by cap 112. The sealing effect of the gas ballast valve 90 is based on the axially compressed O-ring. When the valve 90 is actuated, relative motion is applied to the O-ring. If dirt (e.g., particles) reaches the surface of the O-ring, there is a risk of premature failure. Cap 112 prevents dirt and the like from seeping into the screw of handle 92.

[0082] The cover 112 is attached by an interference fit of three centering elements. Specifically, the cover 112 has an insert pin (not shown) for each hole 108, by which the cover 112 is held in the hole 108. The holes 108 and 110, and the fastening screws arranged therein, are thus protected from contamination. In particular, with the fastening screws (not shown) arranged in the hole 110 and allowing rotational movement, the entry of dirt into the valve mechanism can be effectively minimized, thereby improving the service life of the valve.

[0083] The plastic handle with its overmolded stainless steel base ensures good corrosion resistance and low manufacturing costs. Furthermore, the plastic handle remains cool due to limited heat conduction, making it easier to use.

[0084] Preferably, fan 44 is provided with speed regulation, for example, it can be provided with speed regulation. Figure 1 and Figure 3 As seen in the diagram, for example, the fan is controlled via PWM based on the power consumption and temperature of the power module, which is mounted in, for example, an electronic component housing 48. The fan speed is set in the same way as the power consumption. However, adjustment is only allowed starting from a module temperature of 50°C. If the pump enters a temperature range that may derating (temperature-related power reduction), the maximum fan speed is automatically activated. Through this adjustment, the lowest noise level can be achieved when the pump is cold, and the noise level is low at final pressure or low load (corresponding to pump noise) while achieving optimal pump cooling at a low noise level, and ensuring maximum cooling capacity before temperature-related power reduction occurs.

[0085] The maximum fan speed can be adjustable, depending on the specific circumstances. For example, reducing the maximum fan speed can achieve higher water vapor tolerance.

[0086] exist Figure 12 Compared to Figure 5 A partially enlarged view shows the movable helical component 30. Along... Figure 12 The cross-sectional view of the helical component 30 of line A:A shown in the figure. Figure 13 It is shown schematically and is not drawn to scale.

[0087] The spiral wall 28 has a groove 114 at its end away from the base plate 66 and toward the fixed spiral component 24 (not shown here) for inserting a sealing element 64 (also not shown here) (i.e., a so-called tip seal). The arrangement in the operating state is, for example, in… Figure 4 It is clearly visible in the middle. In a preferred embodiment of the pump according to the invention, a tip seal is provided that frictionally contacts the sliding layer.

[0088] The groove 114 is defined by two opposing sidewalls, one outward and one inward, namely the inner sidewall 116 and the outer sidewall 118. In the first helical portion 120, the outer sidewall 118 is designed to be thicker than the inner sidewall 116 in the first helical portion 120, and thicker than both sidewalls 116 and 118 in another second helical portion 122.

[0089] The first spiral section 120 from Figure 12 The position shown extends to the outer end of the spiral wall 28, for example, as Figure 5 As shown. The first spiral portion 120 extends, for example, more than approximately 163°.

[0090] The first helical portion 120 forms the outer end of the helical wall 28. The first helical portion 120 is arranged at least partially, and particularly completely, in the non-pumping region of the helical wall 28. In particular, the first helical portion 120 may at least substantially completely fill the non-pumping region of the helical wall 28.

[0091] like Figure 5 As can be seen, the first intermediate portion 70 can preferably be arranged between the two retaining protrusions 68. The first intermediate portion has a greater radial height than the other intermediate portions 72 and 74, and is arranged opposite to the first spiral portion 120. The imbalance introduced by the thicker sidewalls 118 can therefore be compensated by the greater weight of the first intermediate portion 70.

[0092] For low system loads on bearings and other components, movable helical components should generally preferably have low self-weight. Therefore, the helical walls are typically designed to be thin. Furthermore, the thinner the wall, the smaller the pump size (significant outer diameter). Consequently, the sidewalls of the tip seal groove are particularly thin. For example, the ratio of the tip seal wall thickness to the total helical wall thickness is 0.17 or less. However, due to the tip seal groove, the tip of the helical wall is very sensitive to impacts during handling, such as during assembly or when replacing the tip seal. Even slight impacts, such as during transport, can push the sidewalls of the groove inwards, rendering the tip seal unusable. To address this, the groove has an asymmetrical wall thickness, particularly with localized thickening of the helical wall towards the outside. This area is preferably not the pumping action area and can therefore be manufactured with greater tolerances. Thickening one side of the winding, particularly the latter half, significantly reduces damage. At other locations on the component, thickening of the helical wall is preferably unnecessary, as the wall is protected by the protruding elements of the component.

[0093] Figure 1The air guide shroud 46, as shown, defines the airflow as indicated by the dashed arrow 124. The fan 44 is connected to a control device within the electronics housing 48 via a cable (not shown) passing through the air guide shroud 46 and a plug connection. The plug connection includes a socket 126 and a plug 128. The socket 126 is mounted on and / or attached to a circuit board disposed within the electronics housing 48. The socket 126 may also be, for example, in… Figure 2 and Figure 3 As seen in the image, plug 128 is connected to fan 44 via a cable (not shown).

[0094] The plug connectors 126 and 128 are separated from the airflow 124 by a partition wall 130. The airflow 124, which may contain dust or similar contaminants, is thus kept away from the plug connectors 126 and 128. Therefore, the plug connectors 126 and 128 are protected on the one hand, and on the other hand, contaminants are prevented from entering the electronic component housing 48 through the opening provided for the socket 126 and reaching the control device and / or power electronic equipment.

[0095] Air guide shroud 46 Figure 14 The image is shown separately in perspective view. In particular, the partition wall 130 can be seen, behind which a defined space is provided for the plug 128. The partition wall 130 includes a recess 132 designed as a V-shaped notch here for leading the cable from the plug 128 to the fan 44.

[0096] For example, to save costs, inexpensive plug connectors can be used without sealing (e.g., no IP protection), because the partition wall 130 ensures that the intake air does not reach the electronic equipment through openings in the plug connectors 126, 128. The fan cable is guided laterally through the partition wall 130 through the V-groove 132. The groove 132 is laterally offset relative to the plug connectors 126, 128, thus creating a labyrinth effect and therefore further reducing cooling air leakage to the plug connectors 126, 128. The partition wall 130 within the air guide shroud 46 also improves the airflow into the channel 50 between the electronic component housing 48 and the pump housing 22. The fan 44 experiences less turbulence and back pressure.

[0097] Figure 15 A schematic cross-sectional view of the contact area between the first housing element 22 and the second housing element or retaining screw component 24 is shown. The second housing element 24 is partially inserted into the first housing element 22 via a transition fit 134. A seal is provided via an O-ring 136. The transition fit 134 is also used, for example, to center the second housing element 24 relative to the first housing element 22.

[0098] For maintenance purposes, such as replacing the sealing element 64, it may be necessary to remove the second housing element 24. If the second housing element 24 is not pulled out sufficiently, the transition fit 134 or the O-ring 136 may become stuck. This problem is solved by providing a clamping thread 138. Preferably, the second clamping thread may also be provided at least substantially radially opposite. To loosen the second housing element 24 as straight as possible and in a guided manner, a screw may be screwed into the clamping thread 138 until the screw protrudes and contacts the first housing element 22. With further screwing, housing elements 22 and 24 are pushed away from each other.

[0099] For example, the fastening screws 142 used to secure the second housing element 24 to the first housing element 22 can be used for clamping, for example as they are in Figure 1 and Figure 3 The 3 mark indicates this. For this purpose, the clamping thread 138 preferably has the same thread type as the fastening thread provided for the fastening screw 142.

[0100] A countersunk hole 140 is provided on the second housing element 22 and is assigned to a clamping thread 138. If wear particles are expelled when the screw is screwed into the clamping thread 138, they accumulate in the countersunk hole 140. This prevents such wear particles from, for example, obstructing complete contact between housing elements 22 and 24.

[0101] When assembling the retaining screw component 24, the screws must be unscrewed again; otherwise, it may prevent the retaining screw component 24 from being fully tightened onto the first housing element 22 (properly secured to the plane of the housing). This could lead to leakage, misalignment, and reduced pump performance. To avoid such assembly errors, the air guide shroud 46 has at least one, particularly additional, such as Figure 14 The cross-shaped part (Dom) 144 shown allows the air guide shroud 46 to be assembled only after the clamping screws, particularly the fastening screw 142, have been removed again. This is because the air guide shroud 46 with the cross-shaped part 144 is designed to collide with the screw head of the clamping screw that has been screwed into the clamping thread 138, thus preventing the air guide shroud 46 from being fully installed. In particular, the air guide shroud 46 can only be installed after the clamping screw has been completely removed.

[0102] Figure 16A schematic detailed view of the screw pump or vortex pump 20 according to the foregoing figures is shown in the area where the seal 150 contacts the carrier 154 in the form of a base plate 66, where the sliding layer 152 is provided. Specifically, the screw elements 26, 28 are arranged such that the seal 150 is pressed against the carrier 154 in the form of the base plate 66. The seal is pressed against the base plate by the pressure difference between the two sides of the screw elements 26, 28. The seal 150 is connected to the screw elements 26, 28 via an interface 151. The sealant for the oxide layer and the sliding layer 152 is not shown separately because the sealant has penetrated into and sealed the pores and defects of the oxide layer. No additional layer structure is necessary. Preferred fluoropolymer sealants not only improve the dry lubrication performance of the sliding layer 152 and further reduce its wear, but also improve the airtightness of the sliding layer 152, thereby improving the achievable final pressure and reducing the break-in time.

[0103] The carrier 154, in the form of a base plate 66, and the spiral walls 26 and 28 are each formed in one piece and are made of AlMgSi type aluminum alloy. The oxide layer of the sliding layer 152 is an aluminum oxide layer generated by anodizing in sulfuric acid electrolyte. The sliding layer 152 is specifically applied to all surfaces of the spiral components 24 and 30 facing the conveying chamber. Figure 6 The seal 150 (tip seal) shown is, for example, polytetrafluoroethylene containing polyimide particles, manufactured by hot pressing followed by sintering. The average particle size of the polyimide particles is 25µm.

[0104] The sealant is preferably applied as an aqueous anionic polyurethane dispersion, wherein the polyurethane comprises perfluorinated polyether segments. The perfluorinated polyether segments can exist as polyol prepolymers or as diisocyanate prepolymers. The perfluorinated polyether segments can be, for example, segments based on perfluorinated polyethylene glycol or perfluorinated polypropylene glycol, preferably based on perfluorinated polyethylene glycol. A tackifier is added to the polyurethane dispersion to improve the bonding between the sealant and the oxide layer. For example, epoxysilanes or polyaziridinium can be added. Alternatively or additionally, other tackifiers, such as melamine or blockierte isocyanate, can also be added. The sealant can also be acrylate-based or sol-gel-based, wherein the use of the tackifier described above is preferred in the case of acrylate-based or sol-gel-based sealants.

[0105] The pump according to the present invention may have the above reference. Figures 1 to 16 One or more of the described features, wherein any combination of these features can be implemented in the pump according to the invention.

[0106] Figure 17 An electron micrograph shows a cross-section of an oxide layer 156 with a thickness of 39.08 µm applied to a substrate 66. Figure 17 The scale bar shows a length of 10µm. The oxide layer 156 has cracks 158 and defects 158 that compromise the airtightness. Figure 18 A further magnified view is shown, in which the pore structure and the defects that connect the pores to each other can be seen. Figure 18 The scale bar in the image shows a length of 200 nm. The porous structure of oxide layer 156 can also be seen from... Figure 19 From this, we can see that Figure 19 show Figure 17 and Figure 18 An electron microscopic planar image of the oxide layer, in which pores 160 are shown as dark vertical stripes, and very small defects 158 can also be seen as dark spots connecting adjacent pores 160 to each other. Figure 18 The scale bar in the image shows a length of 200 nm, revealing very small pores 160, as well as larger pores 160 and cracks 158, and their branching. Figures 17 to 19 In the figure, only a few pores and defects are marked with the attached diagram.

[0107] The effect of the sliding layer of the pump according to the present invention can be derived from... Figure 20 As shown in the chart, time is plotted in hours on the horizontal axis (X-axis), and pressure in hPa is plotted on the vertical axis. Under the same conditions, a vortex vacuum pump generates negative pressure, with the corresponding negative pressure development recorded over time.

[0108] All lines A through D use HiScroll type pumps, the only difference being that the conveying element in line A has no coating. In line B, the conveying element has a coating as described in EP 3 153 706 A1, where sulfuric acid electrolyte is used to generate the oxide layer, i.e., the oxide layer produced by anodizing. Line C uses a HiScroll pump like line B, but the coating is heated for a period of time before vacuum is generated. Line D illustrates the development of a vacuum with a vacuum pump according to the invention, wherein the oxide layer is additionally sealed with a sealant.

[0109] As shown in line A, although a low final pressure can be quickly achieved using an uncoated conveyor element, this is not stable due to wear of the conveyor element. If the conveyor element has an anodized coating, a stable but relatively high final pressure can be achieved even after a long break-in period. Line B clearly illustrates this. Using a pump from line B, the test was interrupted after a short run, and a sealant was applied to the oxide layer. If the test continued, it was found that the pressure dropped more quickly, reaching a significantly lower final pressure. Line C shows that a lower final pressure can be obtained by heating the conveyor element, which, like in line B, was used until the test was interrupted. However, defects contained in the oxide layer cannot be removed by heating, therefore, by... Figures 17 to 19 The visible cracks suggest some backflow of the conveying medium. The achievable final pressure is better than with the unheated conveying element. However, there is still room for improvement. The sealed conveying element used in line D achieves a significantly lower final pressure than in lines B (until the test was interrupted) and C, where the resulting vacuum, unlike in line A, is stable. In the cases of lines B and C, a significantly longer break-in time is expected before reaching the lower final pressure. Using the sealant according to the invention not only improves the tendency towards the achievable final pressure but also significantly reduces the break-in time. This demonstrates the significant effect of the sealant, due to the porous structure of the oxide layer, in terms of short break-in time, low final pressure, and high wear resistance.

[0110] List of reference numerals

[0111] 20 vortex pump

[0112] 22 First housing element

[0113] 24 Second housing element / fixed screw component

[0114] 26 Spiral Wall

[0115] 28 spiral walls

[0116] 30 movable spiral parts

[0117] 32 eccentric shaft

[0118] 34 motors

[0119] 36 rolling bearings

[0120] 38 eccentric pin

[0121] 40 rolling bearing

[0122] 42 Corrugated Pipe

[0123] 44 fans

[0124] 46 Air Guide Duct

[0125] 48 Electronic component housing

[0126] 50 channels

[0127] 52 chambers

[0128] 54 ribs

[0129] 56 grooves

[0130] 58 ribs

[0131] 60 pressure sensor

[0132] 62 channels

[0133] 64 sealing elements

[0134] 66 base plate

[0135] 68. Maintain protrusion

[0136] 70 First Middle Section

[0137] 72 Second Middle Section

[0138] 74 Third Middle Section

[0139] 76 clamping device

[0140] 78 Three-jaw Chuck

[0141] 80 groove

[0142] 82 counterweights

[0143] 84 fastening holes

[0144] 86-axis shoulder

[0145] 88 shell shoulder

[0146] 90 gas ballast valve

[0147] 92 Actuation Handle

[0148] 94 Plastic Body

[0149] 96 base components

[0150] 98 holes

[0151] 100 check valve

[0152] 102 plugs

[0153] 104 fastening screws

[0154] 106 rotatable elements

[0155] 108 holes

[0156] 110 holes

[0157] 112 covers

[0158] 114 slots

[0159] 116 Inner wall

[0160] 118 outer wall

[0161] 120 First Helix Section

[0162] 122 Second Helix Part

[0163] 124 airflow

[0164] 126 socket

[0165] 128 plug

[0166] 130 partition wall

[0167] 132 grooves

[0168] 134 Transition Fittings

[0169] 136 O-ring

[0170] 138 clamping thread

[0171] 140 countersunk hole

[0172] 142 fastening screw

[0173] 144 cross pieces

[0174] 150 seal

[0175] 152 sliding layer

[0176] 154 carriers.

Claims

1. A pump comprising: A sliding layer (152), wherein the sliding layer (152) comprises an oxide layer and a polymer-based sealant, the oxide layer being formed by anodic oxidation in an acidic electrolyte. The oxide layer is at least partially covered and / or impregnated by the sealant. The sealant is formed of polyurethane having perfluorinated segments, and / or the sealant is formed of polyurethane having polyether segments, and / or the sealant contains fluoroalkylsiloxanes. The thickness of the sealant is 0.1µm to 35µm.

2. The pump according to claim 1, The pump is a helical or vortex pump (20) having a delivery element (24, 30) designed as a helical element, wherein the sliding layer (152) is applied at least partially to at least one of the delivery elements (24, 30) designed as helical elements.

3. The pump according to claim 1, The pump is a piston pump having at least one cylinder having an inner wall and a piston movable within the cylinder, wherein the sliding layer is applied at least partially to the inner wall of the cylinder and / or the piston.

4. The pump according to any one of claims 1 to 3, wherein the oxide layer is porous, and the sealant at least partially seals the pores (160) and / or defects (158) in the oxide layer.

5. The pump according to any one of claims 1 to 3, wherein the sealant is formed of polyurethane having perfluorinated polyether segments.

6. The pump according to any one of claims 1 to 3, wherein the sealant has a thickness of 10 µm or less.

7. The pump according to any one of claims 1 to 3, wherein the sealant has a thickness of 0.5 µm to 5 µm.

8. The pump according to any one of claims 1 to 3, wherein the sealant has a thickness from 5 µm to 25 µm or from 25 µm to 35 µm.

9. The pump according to any one of claims 1 to 3, wherein the sealant substantially completely covers the oxide layer or completely covers the oxide layer.

10. The pump according to any one of claims 1 to 3, wherein a tackifier is provided in the sealant and / or as a primer on the oxide layer.

11. The pump of claim 2, wherein the conveying element comprises a base material formed at least in part of aluminum or an aluminum alloy, and the sliding layer (152) is applied to the base material.

12. The pump according to claim 1, wherein the pump is a vacuum pump.

13. The pump of claim 1, wherein the sealant is a fluoropolymer-based sealant.

14. A method for generating a sliding layer (152), comprising the steps of: a) In an acidic electrolyte, an oxide layer is formed by anodic oxidation; and b) Coat the oxide layer with a sealant. The method described therein is a method for manufacturing a pump according to any one of claims 1 to 13.

15. The method of claim 14, wherein the sealant is applied in the form of an aqueous dispersion or in the form of a solvent-based dispersion.

16. The method of claim 15, wherein the solvent in the solvent-based dispersion is a C1 to C8 alcohol.

17. The method of claim 15, wherein the solvent in the solvent-based dispersion is a C3 to C6 alcohol.

18. The method of claim 15, wherein the solvent in the solvent-based dispersion is a C4 alcohol.

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