JP2019113064A - Screw-type vacuum pump - Google Patents

Abstract

To improve temperature situation of a screw-type vacuum pump.SOLUTION: A screw-type vacuum pump (10) has a housing (16), and two screw rotors (28, 30) disposed in the housing (16) in a state of being engaged with each other. The screw-type rotors repeatedly form a conveyance amount in which a process gas is enclosed to convey the same to a direction of an outlet (24) while interacting with the housing (16). The screw-type vacuum pump (10) has a motor (12), the motor is formed as a direct driving portion for one of the screw-type rotors (28), and an active fluid cooling portion is disposed for the screw-type rotors (28, 30) and the motor (12).SELECTED DRAWING: Figure 1

Description

  The present invention relates to a screw-type vacuum pump having a housing, a screw-type rotor provided in the housing and in engagement with each other. The screw-type rotor interacts with the housing for the transport of the process gas, forms the transport volume of the process gas closed repeatedly and transports in the direction of the outlet.

  The vacuum technical performance of the screw-type vacuum pump depends on the size and number of the gaps in the area which exerts the pump effect, in particular between the screw rotors engaged with each other, and between each screw rotor and the surrounding housing wall. It depends heavily. These gaps are deformed by heat-dependent deformation, in particular expansion, of the components involved in comparison to the operating or static state. By controlling the generation of heat in the screw pump and the high temperature limitation or avoidance, the influence of the temperature on the gap and thus the influence on the vacuum technical performance of the screw pump is improved It is possible.

  Moreover, reducing heat generation can improve the efficiency of a screw-type vacuum pump, since heat basically corresponds to a loss, unless exposed at most places. There is a close relationship between the power consumption of the pump and the heat that is generated, where high power density requires efficient heat dissipation.

German Federal Patent Application Publication No. 19775615 A1

  The object of the present invention is to improve the temperature profile of a screw-type vacuum pump of the type described at the outset.

  This task is solved by the features of claim 1.

  Further, a screw vacuum pump is disclosed having a housing, a screw rotor provided in the housing and in engagement with each other. The screw rotor interacts with the housing for the transfer of the process gas, forms the closed process gas transfer volume repeatedly and transfers in the direction of the outlet, where the screw vacuum pump It has at least one of the features described.

  A motor can be provided. The motor is formed as a drive of a screw rotor. Since the motor is formed as a drive, there is no need to provide a connection between the motor and the associated screw rotor. Since the connection basically generates heat during operation, the heat source is thus completely avoided. Furthermore, corresponding mechanical losses at the connection are avoided, which improves the energy efficiency of the pump.

  Active fluid cooling may be provided. The term "active cooling" relates to externally operated cooling, i.e. fluid cooling, in particular by a pump. In that case, for example, a separate pump can be provided or, in any case, the water pressure on the water pipe can be used. For example, the active cooling can be water cooling. Active cooling is used for rapid heat removal and in doing so helps to limit the temperature in the screw pump.

  Active fluid cooling can be provided both for the screw rotor and for the motor. Thus, the temperature is limited both in the area of the motor and in the area of the screw rotor, ie in the pump where particularly high heat generation is expected. The term "for" also includes that the active cooling part is provided directly in the element in the area of the element, ie also in the area of the screw rotor or motor, for example. Thus, for example, in the context of the present invention, the active cooling can be provided in the housing of the screw rotor, or in the housing, in particular in the axial region in which the screw rotor is arranged. . Essentially only one active fluid cooler can be provided, both for the motor and for the screw rotor, or a plurality of active fluid coolers can be provided. Is also possible.

  In particular, the directly driven screw rotor forms the rotor of the motor. Thus, no additional bearing is required for the screw rotor, which further reduces mechanical losses and the corresponding generation of heat.

  The motor can, for example, be a permanent magnet synchronous machine, have a magnet located inside the unwinder, or be configured as an IPMSM. Thus, the efficiency can be further improved. In particular, extra efficiency can be achieved with IPMSM.

  According to one embodiment, in particular an external frequency converter is provided for the motor. In particular, due to the lack of moving parts, this likewise contributes to the reduction of mechanical losses. Thus, for example, there is no need to provide a conversion gear between the motor and the associated screw rotor. Since the connection basically generates heat during operation, the heat source is thus completely avoided. Furthermore, in this way corresponding mechanical losses at the connection are avoided, which further improves the energy efficiency of the pump. However, it is possible, for example, to provide a synchronous gear between the screw rotors, except that a conversion gear is not necessary between the motor and the corresponding screw rotor.

  In a further embodiment, the screw rotors each have at least two parts adjoining along the screw axis, wherein the screw rotors are each in a first part placed near the inlet. There is at least essentially a constant or increasing slope in the second portion, and a lower slope in the second portion than in the first portion. Then, with respect to the screw axis, the first part is longer than the closed conveying distance in the first part, in particular more than one revolution of the screw profile or 360 degrees. This increases the gap length between the compressed area and the inlet of the pump, which improves the corresponding sealing. Thus, the pump can be formed more efficiently. Furthermore, this can reduce the required working quality of the cover surface for the screw rotor in the inlet area. This lowers the manufacturing cost of the pump.

  In a further development, an overpressure valve is provided in the region of the compression inside the pump. This is connected to or forms an outlet of the pump. This allows any pressure not needed to be released from this area when the pressure at the outlet, ie normal atmospheric pressure, is exceeded. The inner compression is thus limited to atmospheric pressure. This eliminates the drive power required for further compression and correspondingly avoids further heat of compression. This leads to a drop in temperature.

  For example, the pump may have a controller, which may be configured or provided to operate the pump at least about 120 Hz, in particular at least about 80 Hz, at least in the normal operating mode. It is. By this, correspondingly low power consumption or correspondingly low mechanical losses are achieved. This is especially true in the area of the discharge pump stage. Here, or in the outlet region, the rotor temperature and the housing temperature and the outlet gas temperature are kept low.

  According to another embodiment, the controller is configured and / or provided to operate the pump in at least a temporally at least in the reinforced operating mode, in which the rotor speed is in the normal operating mode Higher than in While this allows the performance to be further enhanced if necessary, but in the normal operating mode, it is possible subsequently to maintain low power consumption or low heat generation. In other words, an efficient pump is provided as a whole, but it can be used flexibly. This embodiment is advantageous, for example, in particular for frequently repeated applications for vacuuming. Here, respectively, an output is added as needed to start the vacuum, where the power consumption and heat generation remain relatively low as average. In particular, it is possible to overload the motor for fluid cooling for a short time. Thus, a small designed motor can be sufficient for driving the screw vacuum pump.

  One development is characterized in that a non-contacting seal, in particular at least one piston ring, is provided for at least one screw rotor. The heat generation can thereby be further reduced, in particular in comparison to a pump with a radial shaft seal.

  A lubricant discharger, for example a deflector, can be provided, in particular adjacent to the seal. It is possible to support a seal for a screw rotor. The support is provided by the fact that, in particular, the majority of the lubricant, for example oil, has already reached no seal at all and is drained first. This can in particular improve the non-contacting seal in its sealing action.

  The screw rotors can, for example, be connected via synchronous gears. The synchronization gear then has straight teeth. It has a small contact surface in the engaged state, in particular in comparison with the beveled teeth. Correspondingly, less heat is generated in the engagement area of the correspondingly designed gear.

  Furthermore, it is advantageous, thermally technically, that a low lubricant, for example an oil, be used for the synchronous gear. Of course, sufficient lubricants need to be present. This is to ensure lubrication. Less lubricant leads to less mechanical loss than lubricant.

  Moreover, the pump is intended that at least one heat source, eg an internal compression, ie a motor, or a gear is arranged near at least one heat sink, eg a fluid cooling part It is possible. This guarantees particularly efficient heat dissipation.

  According to another embodiment, the at least one heat source is located away from the at least one heat-sensitive area, for example the heat-sensitive component and / or the area to be oil lubricated, or the heat source and the heat The pump is formed such that a shield is formed between the sensitive areas.

  The shield can, for example, be formed by a side cut of the housing. Sidecuts limit possible heat flow and thus provide efficient isolation. At the same time, sidecuts can be made easily and in particular do not require additional isolation.

  In particular, it is advantageous to provide an active cooling in the area of the side cut. As such, heat retention in this area can be efficiently dissipated. The sidecut then acts like a so-called heat collection point for the active cooling, so that heat basically does not pass through or hardly passes through the sidecut, but of the active cooling Mostly supplied.

  A shield can be provided, in particular, between the outlet and the bearing part for the screw rotor. Thus, in particular, the lubricant present in the bearing part can be protected against the ingress of much heat from the outlet area. Lubricants are often heat sensitive or, because of the higher temperatures, sourcing is expensive.

  The shield can be formed as an isolating part, for example as an isolating layer, in particular by a material which is less likely to conduct heat, for example by a foamable material or a gas such as air. For example, the bearing part, in particular the bearing shield, can be formed as a sandwich element, in particular by (or with) a separating layer. As a result, the heat transfer from the area exerting the pump effect to the bearing area can be further reduced.

  In another embodiment, the fluid cooling portion is formed such that it forms turbulence in the area of the heat source. This guarantees particularly good heat transfer. In principle, it may be advantageous to envisage a low volume, in particular a small cross section of the cooling circuit and / or a low total fluid volume, and / or a high flow rate of the cooling fluid. This enables particularly good heat transfer, in particular by the formation of turbulent states. Turbulence can also be created, for example, by locally narrowing the cooling piping or by suddenly changing its internal area.

  In general, it may be intended to guarantee efficient cooling, in particular by means of local rapid thermal entrainment, in particular directly or as close as possible to the heat source. Thus, for example, the cooling piping of the active cooling part can comprise aluminum or another material with high thermal conductivity, can be formed in an aluminum casting and / or In particular, it can be designed as a cooling pipe embedded in the housing groove. The cooling pipes are in particular arranged close to the heat source and / or follow their contours as close as possible. In general, the cooling circuits can be split and / or properly connected for cooling of various heat sources. Here, for example, a part of the cooling circuit can be provided completely for the particularly hot or heat-sensitive area, in particular for the particularly hot or heat-sensitive component. On the other hand, other parts of the cooling circuit can be connected in series to other less sensitive or less heat emitting areas or components.

  Moreover, it is advantageous to arrange the heat sources in the pump together, adjacent and / or close to each other, in order to improve the cooling piping. By this it is possible that local cooling is already achieved. It is for cooling a plurality of heat sources in common. The heat generated in a concentrated manner can be dissipated particularly well.

  In particular, it may be advantageous to locate the unavoidable heat source near the outlet. The outlet is then in particular itself a heat source. The heat can be dissipated locally here particularly efficiently.

  For example, an immersion cooler can be provided. It contains especially aluminum. The immersion cooler can be arranged, for example, in a vacuum pump, in particular a synchronous gear lubricant bath, in particular an oil bath. The temperature of the sensitive lubricant can thereby be managed particularly well, or can be used for localized cooling in this temperature-sensitive area, Other areas may need to be cooled less often.

  The screw rotor of the screw vacuum pump can in particular be formed by or have a cycloidal profile and / or be formed in two stages. The screw inclination of the screw rotor can, for example, be formed partially constant, that is to say the inclination changes only at the transition region between the partial parts along the screw axis. The transition area is then in particular smaller than one part, in particular all the transition areas are smaller than all parts.

  The outlet of the pump can, for example, be directed downwards. The inlet of the pump can, for example, be directed upwards.

  The screw-type vacuum pump has, for example, an internal compression with a compression ratio less than 5: 1, in particular less than 4: 1, in particular less than 3.5: 1, and / or greater than 2: 1, in particular greater than 3: 1. It is possible to Each screw profile forms or conveys, for example, a closed conveying volume of more than 7, in particular more than 10, in particular more than 12 and in particular more than 13. The ratio of the length of the screw profile of each screw rotor to its diameter is in particular at least 2.0, in particular at least 2.5, in particular at least 3.0, and / or at most 5.0, in particular at most 4.0 is there.

  In an exemplary method for the operation of a vacuum system having a screw vacuum pump, in particular a screw vacuum pump according to the type described above, the vacuum chamber is in particular often frequently, in particular several times a day, in particular several times an hour A roller piston pump is provided which is repeatedly evacuated and in particular is preconnected to the screw pump, wherein in particular the roller piston pump is at most three times the suction performance of the screw vacuum pump, in particular the highest. The suction performance is doubled or approximately doubled.

  Because repeated vacuuming, also referred to as load lock applications, is often or generally relatively long and operated at high pressures near the environment, the above-mentioned advantageous suction performance ratios and / or low compression ratios are low It leads to the fact that only compressed output needs to be provided and only low heat of compression is generated. The heat of compression can be discharged easily by this. Thus, a particularly efficient operation of the vacuum system is possible.

  In an exemplary method for the operation of a screw vacuum pump, in particular a vacuum system having a screw vacuum pump according to the type described above, the vacuum chamber is operated basically at a final pressure for a prolonged period, in particular A roller piston pump is provided which is preconnected to the screw pump, wherein in particular the roller piston pump has a suction performance which is at least five times, in particular at least seven times higher, than the suction performance of the screw vacuum pump.

  During preferential operation at final pressure, the above-mentioned advantageous suction performance ratios and / or high compression ratios do not lead to the above-mentioned disadvantages. Rather, it is possible to use a screw vacuum pump which is set small, which is cost-effective.

  It is advantageous to set the suction performance ratio and / or the compression ratio in such a way that a suitable compromise can be achieved if repeated evacuations and / or relatively long operation at the final pressure is also necessary or to be possible. It can be.

  The pumps, pump systems and methods described herein can be developed in the sense of features or measures for the pumps, pump systems and methods described herein.

  The invention will be described below by way of example only and based on a simplified drawing.

Perspective view of screw type vacuum pump Top view of the screw type vacuum pump of FIG. 1 Side view of the screw vacuum pump of FIGS. 1 and 2 Sectional view of screw vacuum pump along line A-A shown in FIG. 3 Immersion cooler of screw type vacuum pump shown in Figures 1 to 4

  The screw-type vacuum pump is shown in FIGS. 1 to 3 and comprises a motor 12, a gearbox 14, a housing 16, a bearing shield 18 and a cover 20. The screw-type vacuum pump 10 conveys the process gas from the inlet 22 to an outlet 24 directed downward and visible in FIG.

  An active fluid cooler is provided for the motor 12. It is out of the housing of the motor 12. An active fluid cooler is likewise provided for the screw rotors 28 and 30 provided inside the housing 28 and which can be seen in FIG. It has two cooling pipes. These are not represented in FIG. However, the extension is represented by the corresponding groove 32 of the housing 16. Cooling pipes are inserted into these grooves. Further active fluid coolers are provided in the gearbox 14 and in the cover 20 and are here each formed as a dip cooler 34. These are explained in more detail below on the basis of FIG.

  As can be seen in FIGS. 1 to 4, the housing 16 of the screw vacuum pump 10 has a side cut 36. Sidecuts 36 are provided in the area of the outlet 24.

  The screw type vacuum pump 10 is shown by FIG. 4 in sectional drawing. The cross section corresponds to line A-A in FIG. Two screw rotors 28 and 30 can be seen. They each have two stages, telescopically engaged screw-like profiles 38 and 40. They are made using a cycloid profile and have a cylindrical basic shape of the screw-like base and a cylindrical sleeve contour. The screw profiles 38 and 40 interact with the housing 16 to form the pumping area of the screw vacuum pump 10. Then, it repeatedly transports the closed transport amount from the inlet 22 to the outlet 24, that is, from the left to the right.

  The pump performance of the screw-type vacuum pump 10 depends on the size and manner of the various gaps in the area where the pumping effect is achieved. This is unavoidable based on the relative movement of the rotors 28, 30 and the housing 16, but for good pump performance it should be kept as small and as constant as possible. The temperature change in the involved member leads to its deformation. The measures described here for avoiding, entraining and generally suppressing the heat in the pump 10 thus achieve the least possible deformation and thus the possibly overwhelming clearance. The gap can thus be considered exactly, which improves the pump performance or its efficiency.

  The screw motor 28 is driven by the motor 12 directly, that is, not via an intermediate connection. On the contrary, the screw motor 30 is driven at a predetermined angle with respect to the screw rotor 28 by the gear 43 via the synchronous gear 42.

  The motor 12 has a housing 44. The housing is for example made of aluminium, in which a cooling pipe 26 for the active fluid cooling is formed. The motor 12 further has a winding stator 46. This stator together with the magnet carrier 48 provided at the shaft end of the screw rotor 28 forms a magnetic motor and a direct drive for the screw rotor 28. The screw rotor 28 forms the rotation of the motor 12. The magnet carrier 48 has a plurality of permanent magnets. The motor 12 forms a permanent magnet synchronous machine with integrated magnets, also referred to as IPMSM.

  The stator 46 is disposed within the casting 50, which insulates the non-explained conductors in the stator 46 and guides it to the substrate 52 while insulating it. The casting 50 is here connected with the substrate 52 and forms a vacuum tight connection of the motor 12. This connection is to control electronics provided in the area of atmospheric pressure. For example, an external frequency converter for the motor 12 can also be provided. Alternatively or additionally, at least part of the control electronics for the motor 12 can be provided on the substrate 52.

  A synchronous gear 42 is provided in the gearbox 14. Further, oil is disposed as a lubricant in the gearbox 14. This is distributed by the splash disc 54 over the synchronization gear 42 and over the adjacent bearing 56.

  The side cuts 36 form a shield or a thermal barrier. This is in particular due to the heat generated during the pump operation, in particular in the region of the screw rotors 28, 30. By leaving less material cross-section and changing the heat path by deformation, the heat from the screw motor (heat that would otherwise spread in the housing 16) is prevented from reaching other areas . Thus, the oil is protected in the gearbox 14 and the bearing 56 from too high a temperature. An immersion cooler 14 arranged in the gearbox 14 likewise contributes to the temperature reduction. This is placed in an oil reservoir (not shown) in the gearbox 14 and thus cools the oil directly.

  For each screw rotor 28 and 30, adjacent to the bearing 56 (here forming a fixed bearing), a lubricant entrainment device formed as a deflector 58 is provided. Each deflector 58 forms a barrier for oil in the gearbox. Therefore, it does not reach the area where the pump effect is exhibited or the vacuum area, especially the outlet area. The deflector 58 has a centrifuging edge for the oil which can not be seen in detail. A flow-off groove is formed in the housing 16 for the centrifugation edge. This flow-off groove contains the oil to be centrifuged and directs it into the gearbox 14 or an oil reservoir there. The oil carried or distributed by the splash disc 54 to the gear 42 and to the bearing 56 is thus discharged again by the deflector 58 to the rotor 28 or 30.

  A piston ring is provided on the piston ring carrier 60 as a dynamic fluid seal. This forms a non-contacting seal and thus prevents frictional heat. Since the deflector 58 returns as much oil as possible to the gearbox 14, there is already as little oil as possible in the piston ring. A totally acceptable sealing is thus achieved with a particularly low heat release.

  The screw rotors 28 and 30 have three portions of different inclination in their respective screw profiles 38 or 40. In the pump direction, the first part 62 forms a suction area on the left in FIG. 4 and is constant and has the largest slope in three parts. The first portion 62 is longer with respect to the screw shaft 63 (which extends along each rotor 28 or 30) than the closed conveying amount in the first portion. The second portion 64 has a plurality of subportions. These are not referenced in detail. The lower parts have different inclinations in the screw profile 38 or 40 respectively. The slope is then smaller than in the first part. The second part 64 forms here the longest part. The third portion 66 with the lower slope forms the discharge portion. The third part is again a constant slope. The inward compression takes place by the decreasing inclination along the pump direction. This compresses the pump gas already before discharge.

  The rotors 28, 30 or the screw profiles 38, 40 can be particularly easily considered and manufactured by the presence of certain parts. As seen in FIG. 4, the extended first portion 62 correspondingly leads to the expanded gap between the screw profiles 28, 30 and the housing 16 so that the path, or gap, is At the transition from the seal to the sections 62 and 64, it is longer for the suction space or for the suction area 67. Correspondingly, the sealability of the gap also increases. This leads in particular to improved sealing to the suction area 67 of the inner seal at high pressure differentials.

  The screw vacuum pump 10 has an inner seal. The screw rollers 28, 30 of the pump 10 again interact with the housing 16 to enclose the closed transport volume. Its size is larger at the inlet end or at the portion 62 than at the outlet end or at the portion 62. The size of the transport is determined by the cross section of the screw profiles 38, 40 and by the inclination thereof.

  The size of the transport at the inlet side or portion 62 determines the theoretical suction performance of the screw pump 10. The inclination of the screw profiles 38, 40 is constant over the portion 62 on the inlet side, so that the transport amount is compressed only after separating through the inner seal. If the rotors 28, 30 surround each delivery too fast, or too late, or if the inner compression starts too early, the theoretical suction performance of the pump will sink.

  The size of each delivery on the outlet side, or portion 66, determines the pump input during operation at the final pressure achievable. The ratio of the size of the transport volume at the inlet side and at the outlet side or in the sections 62 and 66 corresponds to the ratio of the compression inside the pump.

  In portion 66, the inclination is constant over multiple rotations of screw profiles 38,40. The inclination then corresponds approximately to the minimum of the inclination achievable with a given processing tool, and is therefore attributable to the manufacturing technology, especially considering cost. By the multiple rotations, i.e. multiple closed conveying amounts, being intended in the part 66, the backflow as a result of the pressure difference between the gaps is compensated. Overall, in particular the extension of the overall inclination of the rotors 28, 30, and the size between the gaps formed between the rotors 28, 30 and the rotors 28, 30 and the housing 16 are the vacuum technical performance data of the pump, In particular, the suction performance and the final pressure that can be achieved are determined.

  The screw profiles 38, 40 have a particularly low unbalance according to their two-stage aspect. Thus, for example, no compensation elements (requiring additional construction space, such as, for example, compensation masses) and / or compensation holes (where the mass can be stored) are not necessary. The pump can be operated by means of a two-stage cycloid screw profile 38, 40 in a further speed range, in particular by means of a speed ramp and / or in a standby mode of operation.

  Compression of the process gas generally generates heat. The heat is cooled in the screw pump 10, in particular by means of a fluid cooler. The grooves 32 provided for this are visible in FIG. Cooling pipes for the fluid cooling extend here and preferably extend longitudinally over another area of the screw profile, in particular over half the length of the screw profile. In particular, the fluid cooler is arranged at or near the area of the inner compression.

  A bearing shield 18 is fixed to the inlet-side end of the housing 16. This carries in particular a further bearing device with a bearing 68. This forms a loose bearing arrangement. The bearing shield 68 is opposite to the bearing shield 70 (which is integrally formed with the housing but can also be formed separately), which is provided at the opposite housing end on the outlet side. It is also possible that it is formed as an independent member, but also integrally.

  On the inlet side, a piston ring carrier 60 is likewise provided, which likewise has a splash disc 54, a deflector 58 and a plurality of piston rings. They operate in concert with the devices on the outlet side. On the inlet side, another separately formed oil reservoir has a cover 20. A dip cooler 34 is also provided for this oil reservoir. Alternatively or additionally, it is also possible that, for example, cooling pipes are provided in the wall of the bearing shield 14 and / or the cover 20, in particular cast.

  At the beginning of the exhaust pumping process through the pump 10, the inlet 22 is normally at essentially the same pressure as the outlet. Conversely, the pressure at the inlet 22 drops to the final pressure during the exhaust pumping process. The final pressure is essentially zero with respect to the forces generated. Thus, the pressure at outlet 24 exerts a force on rotor 28. This is different from that at the beginning of the drainage pump process. In order to ensure this force, for example, a preloading device, in particular a spring, can be provided. This is in particular provided on the loose bearing of the rotor and / or on the inlet side. The preloading device accommodates, for example, the forces exerted on the rotor by means of beveled gears, and / or generally, operating conditions at varying pressures or pressure ratios, which are suitable for bearing considerations. Compensate regardless of

  FIG. 5 shows how the immersion cooler 34 is arranged in the gearbox 14 or in the cover 20 of the screw vacuum pump 10. In this embodiment, the immersion coolers 34 are configured identically, which leads to less component overlap and lower manufacturing costs.

  The immersion cooler 34 has a cooling pipe 72. It extends through the cooling body 74. The cooling body has a structuring for increasing the surface area of the cooling body. This is to optimize the heat transferability. Immersion cooler 34 further includes a flange 76. The immersion cooler 34 is thereby fixed.

DESCRIPTION OF REFERENCE NUMERALS 10 screw type vacuum pump 12 motor 14 gear box 16 housing 18 bearing shield 20 cover 22 inlet 24 outlet 26 cooling piping 28 screw type rotor 30 screw type rotor 32 groove 34 immersion cooler 36 side cut portion 38 screw profile 40 screw profile 42 synchronization Gear 43 Gear 44 Housing 46 Stator 48 Magnet carrier 50 Casting 52 Substrate 54 Splash disk 56 Bearing 58 Deflector 60 Piston ring carrier 62 First part 63 Screw shaft 64 Second part 66 Third part 68 Suction area 68 Support Part 70 Bearing shield 72 Cooling piping 74 Cooling body 76 Flange

Claims (15)

Housing (16), screw vacuum pump (10) provided in housing (16) and having two screw rotors (28, 30) engaged with each other, the screw rotor comprising a process gas Interact with the housing (16) to repeatedly form a closed transport volume of process gas and transport in the direction of the outlet (24), and the screw vacuum pump (10) , A motor (12), which is formed as a direct drive for one of the screw rotors (28), also for the screw rotors (28, 30) A screw-type vacuum pump (10), characterized in that the motor (12) is also provided with an active fluid cooling. Screw vacuum pump (10) according to claim 1, characterized in that the directly driven screw rotor (28) forms the rotor of the motor (12). 3. A screw-type vacuum pump (10) according to claim 1 or 2, characterized in that the motor (12) is formed as a permanent magnet synchronous machine, in particular with a plurality of magnets located inside. 4. Screw pump (10) according to at least one of the preceding claims, characterized in that for the motor (12) a frequency converter is provided. The screw rotors (28, 30) each have at least two portions (62, 64) adjacent along the screw axis (63), wherein the screw rotors (28, 30) respectively At least essentially constant in the first portion (62) located near the inlet (22) and having a lower slope in the second portion (64) than in the first portion (62), and 5. At least one of the preceding claims, characterized in that, with respect to the screw shaft (63), the first part (62) is longer than the closed conveying volume in the first part (62). Screw-type vacuum pump (10) as described. In the region of compression inside the pump, an overpressure valve is provided, characterized in that it is connected with the outlet (24) of the pump (10) or forms an outlet (24). Screw vacuum pump (10) according to at least one of the preceding claims. The pump (10) has a controller, which is configured or arranged to operate the pump (10) at least about 120 Hz, in particular at least about 80 Hz, at least in the normal operating mode. Screw pump (10) according to at least one of the preceding claims, characterized in that A controller is configured and / or provided to operate the pump (10) in at least a temporally enhanced mode of operation, in which the rotor speed is higher than in the normal mode of operation The screw vacuum pump (10) according to claim 7, characterized in that. 9. Screw type according to at least one of the preceding claims, characterized in that for at least one screw rotor (28, 30) a non-contacting seal, in particular at least one piston ring, is provided. Vacuum pump (10). 10. At least one of the preceding claims, characterized in that the screw rotors (28, 30) are connected via a synchronization gear (42), wherein the synchronization gear (42) has an even number of teeth. The screw type vacuum pump (10) according to any one of the items 11. Screw vacuum pump (10) according to at least one of the preceding claims, characterized in that the pump (10) is formed such that at least one heat source is arranged close to the at least one heat sink. ). The pump (10) is arranged such that the shield (36) is disposed between the heat source and the heat-sensitive area, or at least one heat source is arranged apart from the heat-sensitive at least one area Screw vacuum pump (10) according to at least one of the preceding claims, characterized in that it is formed. The shield is formed by a side cut (36) of the housing (16) and / or the shield (36) of the bearing portion (58) for the outlet (24) and the screw rotor (28, 30) Screw-type vacuum pump (10) according to at least one of the preceding claims, characterized in that it is provided between. A screw-type vacuum pump (10) according to at least one of the preceding claims, characterized in that the fluid cooling part is configured to create a turbulent flow in the area of the heat source. Screw vacuum pump (10) according to at least one of the preceding claims, characterized in that the screw rotor is formed by one, in particular a two-stage cycloidal profile.

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