Vacuum pump for transporting gaseous media

Abstract

The object of the present invention is to provide a vacuum pump for transporting a gaseous medium with increased vapor capacity. [Solution] The problem of the present invention is solved by providing a vacuum pump for transporting a gaseous medium, comprising: a pump system having at least one gas inlet and at least one outlet; a detection unit provided and configured to detect at least one characteristic parameter of the medium; a determination unit provided and configured to determine a moisture characteristic value, which is a measure of the humidity of the medium, based on at least one characteristic parameter and / or the time course of at least one characteristic parameter; and a control unit provided and configured to operate the vacuum pump in a condensation avoidance mode, which affects at least one operating parameter of the vacuum pump in order to increase the vapor capacity of the vacuum pump.

Description

Technical Field

[0001] The present invention relates to a vacuum pump for transporting a gaseous medium, a method for operating the vacuum pump, and a measuring device for determining the humidity of the gaseous medium.

Background Art

[0002] Various types of vacuum pumps are known from the background art. Examples of vacuum pumps are scroll vacuum pumps and Roots vacuum pumps. Such vacuum pumps are called dry-running vacuum pumps because they do not rely on grease or oil for sealing and / or lubricating the vacuum pump.

[0003] A scroll pump is, inter alia, a positive displacement pump that can be used as a compressor or a vacuum pump. A scroll pump is also referred to as a spiral pump or a spiral fluid conveyance device. A scroll vacuum pump can be used to generate a vacuum in a recipient (vessel) connected to the gas inlet of the pump.

[0004] The pump principle underlying a scroll vacuum pump is known from the background art and is explained below. The pump stage of a scroll vacuum pump comprises two, for example Archimedean spiral cylinders, which are fitted one inside the other and are hereinafter also referred to as spiral elements. In this case, each spiral element consists of a wall that extends axially from a support and has a free end face facing away from the support.

[0005] The spiral elements are fitted one inside the other so as to enclose a crescent-shaped volume in sections. In this case, one spiral is fixed and the other spiral can move on a circular track via an eccentric drive.

[0006] Therefore, the movable spiral performs what is known as a centrosymmetric oscillation, also called "rocking." The crescent-shaped volume confined between the spiral cylinders moves further within the spiral element as the movable spiral rocks, and this movement of the volume transports gas from the gas inlet located radially outward to the gas outlet located radially inward at the center of the spiral. To seal the transport chamber of conventional scroll vacuum pumps, seals (so-called tip seals) are provided on each end face of the spiral wall.

[0007] In some applications, vacuum pumps are used to transport gaseous media that contain a certain amount of moisture, i.e., a certain percentage of water vapor. In this context, the characteristic parameters of a vacuum pump are water vapor resistance and water vapor capacity, as defined according to ISO 21360. Water vapor resistance is defined as the suction pressure required to pump pure water vapor without condensing the medium inside the pump. Water vapor capacity is the maximum amount of water vapor that can be pumped inside the pump without condensing the medium. The same applies to other gaseous substances that may condense inside the pump. [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] The object of the present invention is to provide a vacuum pump for gaseous media with increased vapor capacity. The gaseous media is, for example, pure water vapor or a gas mixture containing water vapor. In addition to water, other components may condense during pump operation, which could result in the formation of deposits inside the pump and / or damage to pump components. [Means for solving the problem]

[0009] The problems of the present invention are solved by a vacuum pump having the features described in claim 1 and a vacuum pump having the features described in claim 2.

[0010] The vacuum pump comprises a pump system having at least one gas inlet and at least one outlet. The pump system is understood to be the pump portion of the pump system, which includes the pumping components of the pump.

[0011] The vacuum pump may be a dry-operated vacuum pump. For example, the vacuum pump may be a scroll vacuum pump, or preferably a multi-stage Roots vacuum pump. However, other types of dry-operated vacuum pumps are also possible. Scroll vacuum pumps offer advantages such as being particularly energy-efficient to drive compared to rotary pumps, for example. This is mainly because they have a dry pumping system and the compression of the medium is done by multiple helical windings, whereas in rotary pumps, oil must be circulated and transported. Preferably, in scroll vacuum pumps, an IPM motor (internal permanent magnet motor) is used as the driving medium. Furthermore, scroll vacuum pumps operate with relatively little wear. In the case of a scroll vacuum pump, the pumping system includes, for example, a fixed spiral component and a movable spiral component that moves relative to the fixed spiral component.

[0012] The vacuum pump further includes a sensing unit provided and configured to detect at least one characteristic parameter of the medium. In particular, the sensing unit is provided and configured to detect exactly one characteristic parameter of the medium, thereby saving computing resources and reducing the complexity of the pump. However, the sensing unit may also be provided and configured to detect two or more characteristic parameters of the medium, thereby making more data available for further evaluation.

[0013] The vacuum pump further comprises a determination unit provided and configured to determine a moisture characteristic value based on at least one characteristic parameter and / or the time course of at least one characteristic parameter. The moisture characteristic value is a measure of the humidity of a medium, in particular the water vapor content in the medium. The time course may be a constant course over time and / or a course that changes over time. The determination unit may have a memory for (provisionally) storing the time course.

[0014] In the context of this invention, the term "humidity" should not be understood simply as the water (vapor) content in the medium. It also includes the content of other (gaseous) substances or components that may condense inside the pump during pump operation. Examples of such components include acids, bases, alcohols, cleaning agents, or combinations thereof.

[0015] Furthermore, the vacuum pump includes a control unit provided and configured to operate the vacuum pump in a condensation avoidance mode that affects at least one operating parameter of the vacuum pump in order to increase the vapor capacity of the vacuum pump, particularly the water vapor capacity.

[0016] An operating parameter is, for example, the operating temperature of the vacuum pump. The control unit may be provided and configured to affect exactly one, two, or more operating parameters of the vacuum pump. For example, the control unit may be provided and configured to affect only the operating temperature of the vacuum pump, specifically by increasing the operating temperature.

[0017] Therefore, the vacuum pump according to the present invention has a specially configured operating mode that allows the vacuum pump to be operated when necessary. In this mode, condensation of the medium to be transported in the vacuum pump is avoided, while the vapor capacity of the vacuum pump is increased.

[0018] The occurrence of condensation can cause pump components, particularly the tip seals of scroll vacuum pumps, to wear out or corrode more quickly, and / or deposits to form on pump components that come into contact with the medium. This negatively impacts the service life of the vacuum pump and increases maintenance costs. Furthermore, the occurrence of condensation can lead to an increase in the final pressure achievable by the pump. Therefore, by avoiding condensation, the service life of the vacuum pump can be extended. At the same time, the vapor capacity of the vacuum pump can be increased by influencing at least one operating parameter. Thus, the vacuum pump according to the present invention is characterized not only by improved pumping characteristics but also by improved service life.

[0019] The detection unit, decision unit, and control unit may be structurally separate units. However, they may also structurally form a unit, meaning they may be located within the same housing. In particular, the detection unit, decision unit, and / or control unit are part of an electronics unit or pump adjustment unit (which may be a component of the vacuum pump itself or structurally separate from the vacuum pump) for adjusting the operation of the vacuum pump. The detection unit, decision unit, and / or control unit may be implemented as a software module of the pump adjustment unit, in which case the detection unit may include hardware in the form of a sensor installed within the pump.

[0020] Another vacuum pump for transporting gaseous media, particularly dry vacuum pumps, A pump system having at least one gas inlet and at least one outlet, A control unit is provided and configured to operate the vacuum pump in a condensation avoidance mode, which affects at least one operating parameter of the vacuum pump, in particular the operating temperature of the vacuum pump and / or the state of the gas ballast valve of the vacuum pump, in order to increase the vapor capacity of the vacuum pump. At that time, the control unit is provided with operating means by which the vacuum pump can be manually changed to the condensation avoidance mode.

[0021] The vacuum pump can be changed to the condensation avoidance mode, for example, when the vacuum pump is operating in the normal operation mode and / or when the vacuum pump is started. That is, it means that the vacuum pump can be manually switched to the condensation avoidance mode and / or started in this mode by using the operating means (for example, when the user knows that it is required for the user's application, for example, when maintenance work is being carried out on the system and it is expected that "wet" gas needs to be pumped, etc.). This ensures that no condensation occurs in the pump and / or that any condensation that has already occurred, for example, during the pump's stop state, is removed.

[0022] Manually changing the vacuum pump to the condensation avoidance mode can preferably be done in response to, for example, visual and / or audible warning signals provided by the control unit, thereby ensuring that the user can recognize the need to start the condensation avoidance mode.

[0023] To facilitate the operation, the operating means may include a human - machine interface such as a switch, a button, a touch element, and / or automatic speech recognition. It is also possible to incorporate the operating means into the software of the control unit, and as a result, it can be manually operated, for example, on the GUI (Graphical User Interface) of the control unit.

[0024] The above - described features of the vacuum pump can be combined as required. In particular, the first - described variant may, in addition to the detection unit and the determination unit, be provided with manually operable operating means so that this pump can be manually changed to the condensation avoidance mode.

[0025] Another embodiment is shown in the claims, the specification, and the attached drawings.

[0026] According to one embodiment, the value of the operating parameter of the vacuum pump in the condensation avoidance mode is different from the value of the operating parameter in the normal operation of the vacuum pump, especially when other operating conditions are the same. The amount of the difference in values can be kept constant over time and / or may change over time. For example, the value of the operating parameter of the vacuum pump in the condensation avoidance mode can be increased and / or decreased continuously and / or gradually, starting especially from the value of the operating parameter in the normal operating mode of the vacuum pump.

[0027] According to one embodiment, the control unit is provided and configured to change the vacuum pump to the condensation avoidance mode when the moisture characteristic value falls below or exceeds a predetermined threshold. In other words, the control unit can automatically change the vacuum pump to the condensation avoidance mode, especially switch and / or start in this mode, as a result, the operation of the vacuum pump is greatly simplified.

[0028] The predetermined threshold may be stored in the memory of the vacuum pump, especially in the control unit. The predetermined threshold can also be stored in the cloud.

[0029] According to one embodiment, the control unit is provided and configured to periodically change the vacuum pump to the condensation avoidance mode in order to remove the generated condensate. This may be done automatically or as a preventive measure, regardless of the detected operating parameters of the vacuum pump. This embodiment is particularly advantageous for vacuum pumps without a detection unit and a determination unit.

[0030] The respective duration and / or frequency of the cycles of the pump operation in the condensation avoidance mode may be manually adjustable. When determining the cycles, it is also possible to take into account the type and / or intensity of use of the pump (for example, considering the load / pump speed). The cycles do not necessarily have to be regular.

[0031] According to one embodiment, the control unit is provided and configured to change the scroll vacuum pump from condensation avoidance mode to normal operation mode when the moisture characteristic value determined by the determination unit no longer falls below or exceeds a predetermined threshold. In particular, the control unit is provided and configured to lower the operating temperature of the vacuum pump again when the moisture characteristic value determined by the determination unit no longer falls below or exceeds a predetermined threshold.

[0032] According to one embodiment, the control unit is provided and configured to adjust at least one operating parameter of the vacuum pump based on moisture characteristic values. This means that the control unit can actively change the operating parameter.

[0033] According to one embodiment, the control unit is provided and configured to keep at least one operating parameter of the vacuum pump constant over time, or to change it according to a fixed scheme, in condensation avoidance mode. Alternatively, the operating parameter may be intended to be changed stepwise and / or continuously, as needed. This allows for a further increase in the (water) vapor capacity of the vacuum pump.

[0034] According to one embodiment, the vacuum pump further comprises a measuring unit provided and configured to detect at least one operating parameter of the vacuum pump, and a control unit provided and configured to operate the vacuum pump in condensation avoidance mode based on moisture characteristic values ​​and the operating parameter of the vacuum pump. The operating parameter may be the temperature of the vacuum pump, in particular the temperature of the components of the pump system.

[0035] According to one embodiment, the detection unit comprises at least one pressure measuring device for measuring the pressure of the medium. This means that the characteristic parameter detected by the detection unit is, in this case, the pressure of the medium. The pressure can be determined directly or indirectly. Measuring devices based on indirect measurement principles are described below.

[0036] According to one embodiment, the detection unit preferably comprises at least one pressure sensor located at the gas inlet to measure the intake pressure of the vacuum pump, and the determination unit is provided and configured to determine a moisture characteristic value based on the amount of time and / or intake pressure. This means that the characteristic parameter detected by the detection unit is the intake pressure. If the intake pressure is too high over a period of time (for example, compared to conditions expected with a "dry" gas / gas mixture of the same composition), it may indicate that (water) vapor is present in the medium. For example, if the operating temperature of the pump is particularly low, it may be advantageous to switch the vacuum pump to a condensation avoidance mode.

[0037] According to one embodiment, the detection unit and / or measurement unit comprises at least one moisture sensor for measuring the moisture content of a medium or the surface of a vacuum pump, wherein the determination unit is provided and configured to determine a moisture characteristic value based on the measured moisture content (in some cases, the measured moisture content matches the moisture characteristic value).

[0038] The methods shown for determining moisture content can be combined as needed.

[0039] According to one embodiment, the vacuum pump further comprises a temperature control device for influencing the operating temperature of the vacuum pump, and the control unit is provided and configured to influence the operating temperature of the vacuum pump, particularly by increasing the temperature control device. This makes it possible to improve the steam capacity of the vacuum pump in a simple and effective way, and at the same time extend its service life.

[0040] The temperature control device is preferably located at or just before the outlet, as this is where condensation is most likely to occur. Therefore, this arrangement allows for particularly efficient temperature control.

[0041] For a particularly compact and robust design, the temperature control device may be integrated into the vacuum pump housing, especially the hood.

[0042] The temperature control device preferably includes, or can be configured as, a fan having a rotatably mounted propeller that generates an airflow for dissipating heat from the vacuum pump. In the case of a scroll vacuum pump, the axis of rotation of the propeller may be coaxial with a fixed spiral component. The fan is preferably selectively controllable so that heat dissipation can be adjusted as needed.

[0043] Adjusting the temperature control device by the adjustment unit may include reducing the rotational speed of the temperature control device to 10% to 60%, 20% to 50%, or 30% to 40% of the maximum rotational speed of the temperature control device. In particular, the operating temperature of the vacuum pump may rise by about 5°C to 15°C. Surprisingly, this relatively small temperature change is already sufficient to significantly increase the steam capacity of the vacuum pump. Another embodiment involves the fan being periodically switched off, which can be implemented particularly easily with relatively inexpensive fans where rotational control is not possible.

[0044] Adjusting the temperature control device by the adjustment unit may include switching off the temperature control device to further increase the operating temperature of the vacuum pump.

[0045] Switching off the temperature control device and / or reducing its rotational speed can be done within a limited time to prevent the vacuum pump from overheating and damaging its components. In particular, the adjustment unit is provided and configured to increase the rotational speed of the temperature control device again and / or to appropriately control the temperature control device when the operating temperature of the vacuum pump exceeds a predetermined threshold.

[0046] Additionally or alternatively, the temperature control device may include, or be configured as, at least one heating element and / or at least one heating cartridge to locally raise the operating temperature of the vacuum pump. The fan, as well as the heating element and / or heating cartridge, can be combined as needed to achieve optimal control of the pump temperature.

[0047] According to one embodiment, the vacuum pump comprises at least one controllable gas ballast valve controllable by a control unit. In particular, the control unit is provided and configured to open and close the gas ballast valve at least partially as needed to prevent condensation from occurring inside the pump in condensation avoidance mode. This means that the operating parameter that affects the gas ballast valve is in the (open) state. The operation of the gas ballast valve introduces additional dry gas into the pump, which increases vapor resistance. Vapor resistance can also be improved by increasing the amount of gas ballast.

[0048] This concept can be implemented in addition to, or instead of, influencing another operating parameter (e.g., temperature). In other words, the aforementioned concepts for influencing at least one operating parameter of a vacuum pump can be combined as needed.

[0049] The present invention further relates to a measuring device for measuring the humidity of a medium, particularly the water vapor content in a gaseous medium, and more particularly to a measuring device for a vacuum pump for transporting a gaseous medium, preferably a measuring device according to at least one of the embodiments described above.

[0050] The measuring device comprises at least one piezoelectric pressure sensor, in particular at least one piezoelectric pressure sensor and / or at least one piezoresistive pressure sensor, at least one Pirani pressure sensor, and an evaluation unit, the evaluation unit being provided and configured to determine a moisture characteristic value, which is a measure of the humidity of a medium, in particular the water vapor content in the medium, based on the difference between a first pressure value measured by the piezoelectric pressure sensor and a second pressure value measured by the Pirani pressure sensor.

[0051] The first pressure value is measured based on the piezoelectric effect and is therefore independent of the humidity or water vapor content of the medium. In particular, the moisture content of the medium does not affect the voltage tapped at the piezoelectric crystal of the piezoelectric pressure sensor, which is a measure of the pressure acting on the piezoelectric crystal. Therefore, the first pressure value is used as a reference value. On the other hand, the second pressure value depends on the moisture content of the medium, since the heat transfer from the measuring wire of the Pirani pressure sensor to the medium depends not only on the pressure of the medium but also on the composition of the medium. Therefore, (if the gas composition is known) the difference between the first and second pressure values ​​is a measure of the humidity of the medium. The method for determining this moisture characteristic value is particularly simple and low-cost. Calibration of the measuring device can be performed for each gas composition to be pumped in a "dry" state. In this case, the first and second pressure values ​​should not differ significantly from each other.

[0052] The piezo pressure sensor may include at least one piezoelectric pressure sensor and / or at least one piezoresistive pressure sensor.

[0053] When the measuring device is used in the vacuum pump according to the present invention, the evaluation unit can be integrated with the determination unit.

[0054] The present invention also relates to a vacuum pump for transporting a gaseous medium, and more particularly to a method of operating a vacuum pump for transporting a gaseous medium, according to at least one of the embodiments described above.

[0055] This method involves detecting at least one characteristic parameter of the medium, Determining a moisture characteristic value, which is a measure of the humidity of a medium, in particular a measure of the water vapor content in the medium, based on at least one characteristic parameter and / or the time course of at least one characteristic parameter, and Operating the vacuum pump in condensation avoidance mode, where at least one operating parameter of the vacuum pump, particularly the operating temperature of the vacuum pump and / or the state of the gas ballast valve of the vacuum pump, affects the increase in the vapor capacity of the vacuum pump. Includes.

[0056] The features of the present invention described in relation to vacuum pumps are applicable to measuring devices and methods.

[0057] The vacuum pump according to the present invention is characterized by improved service life and increased steam capacity.

[0058] The present invention will be described exemplary below with reference to the drawings. [Brief explanation of the drawing]

[0059] [Figure 1a] Figure 1a shows a cross-sectional view of a scroll vacuum pump. [Figure 1b] Figure 1b shows an enlarged or detailed view of the scroll vacuum pump shown in Figure 1a. [Figure 1c] Figure 1c shows an enlarged or detailed view of the scroll vacuum pump shown in Figure 1a. [Figure 2] Figure 2 shows a side view of the scroll vacuum pump shown in Figure 1a. [Figure 3] Figure 3 shows a partial diagram of the pumping system of the scroll vacuum pump shown in Figure 1a. [Figure 4]Figure 4 shows a cross-sectional view of a portion of the scroll vacuum pump shown in Figure 1a. [Figure 5] Figure 5 shows a block diagram of the electronic components of the scroll vacuum pump shown in Figure 1a. [Figure 6] Figure 6 shows a block diagram of a measuring device for determining the humidity of a gaseous medium. [Modes for carrying out the invention]

[0060] The present invention will be described below using a scroll vacuum pump as an example. However, the present invention is also applicable to other types of dry-running vacuum pumps, such as Roots vacuum pumps, and preferably multi-stage Roots vacuum pumps.

[0061] The scroll vacuum pump shown in Figure 1a comprises a pump system having a fixed spiral component 11 and a movable spiral component 13, which interact to produce a pumping action during operation. Furthermore, the scroll vacuum pump includes a drive shaft 17 that rotates around a rotation axis 15 during operation to drive the movable spiral component 13, and an eccentric portion 19.

[0062] The scroll vacuum pump comprises electric drive motors 21 and 23 that function to cause the drive shaft 17 to rotate around a rotation axis 15. The electric drive motors comprise a radially inward motor rotor 21 and a radially outward motor stator 23.

[0063] The drive shaft 17 is rotatably supported in the pump housing 41 at two bearing points 25 and 27 that are spaced apart in the axial direction. The front rolling bearing 25 is configured as a fixed bearing, while the rear rolling bearing 27 is configured as a free bearing.

[0064] In one embodiment, both bearing locations 25 and 27 are located on the side of the drive motors 21 and 23 closer to the eccentric portion 19 of the drive shaft 17. Therefore, all bearing locations 25 and 27 are located in front of the drive motors 21 and 23 within the pump housing 41. The eccentric portion 19 is integrally connected to the front end of the drive shaft 17, and the drive motors 21 and 23 are seated at the rear end of the drive shaft 17.

[0065] The drive motors 21 and 23 can be fitted onto the rear end of the drive shaft 17 by this basic structure, thereby facilitating the assembly and replacement of the drive motor or its components.

[0066] In particular, the balancing scheme for the rotating system, which includes the drive shaft 17 and the movable spiral component 13, includes a front balance weight 29 and a rear balance weight 31 attached to the drive shaft 17 using screws 38. In this case, the front balance weight 29 is positioned in the area of ​​the front end and eccentric portion 19 of the drive shaft 17. The rear balance weight 31 is positioned in front of the rear bearing location 27, and consequently in front of the drive motors 21 and 23.

[0067] Optionally, a pressure element 87 (Figure 1b) is provided fitted to the rear end of the drive shaft 17 at its end face. The pressure element 87 is configured rotationally symmetrically and is therefore not used as a balance weight.

[0068] The pressure element 87 or the balance weight 31 are each connected to the drive shaft 17 by screws 83. Thus, the motor rotor 21 is clamped between the rotationally symmetric pressure element 87 or the pressure element 31, which is simultaneously configured as a balance weight, and an opposing bearing, in this case formed by a shoulder 17a formed on the drive shaft 17.

[0069] Furthermore, a sleeve element 33 is provided, positioned between the drive shaft 17 and the motor rotor 21. The sleeve element 33 is non-rotatably connected to the motor rotor 21, and this connection between the motor rotor 21 and the sleeve element 33 is established by applying a pressing force. As a result, the unit consisting of the motor rotor 21 and the sleeve element 33, pressed against each other, can be fitted onto the rear end of the drive shaft 17 during assembly. In this case, a clearance fitting exists between the sleeve element 33 and the drive shaft 17.

[0070] In the aforementioned shoulder portion 17a region, a wave spring 99 is positioned between the sleeve element 33 and the free-side bearing 27.

[0071] A pin-shaped positioning element 85 is used as a positioning assisting means for the pressure element 87 or balance weight 31, as a means to prevent rotation when tightening the screw 83, and as a circumferentially acting shape connection between the motor rotor 21 or sleeve element 33 and the drive shaft 17. This positioning pin 85 extends parallel to the rotation axis 15 of the drive shaft 17 and is positioned radially away from the rotation axis 15. During assembly, the positioning pin 85 can be inserted into a notch in the axial direction. This notch is formed together with the drive shaft 17 on one side and the motor rotor 21 or sleeve element 33 which is non-rotatably connected to the motor rotor 21. In the assembled state, the positioning pin 85 protrudes rearward in the axial direction and is housed in a positioning housing at its rear end. This positioning housing is formed as a blind hole on the side of the pressure element 87 or 31 closer to the rear end of the drive shaft 17.

[0072] The aforementioned tightening of the motor rotor 21 using the pressure element 87 or 31 is achieved by the pressure element 87 or 31 interacting with the axial rear end of the sleeve element 33 or with the motor rotor 21.

[0073] As an assembly aid when press-fitting the sleeve element 33 into the motor rotor 21, a radial protrusion 101 is provided at the front end of the assembled motor rotor 21. This protrusion 101 is used as a mark for the worker and therefore indicates the mounting direction of the motor rotor 21.

[0074] The drive motor is not entirely housed within the pump housing 41. The motor cover 103 has a housing space with axial depth. The axial depth is dimensioned such that the rear end of the drive motor, which protrudes axially rearward from the pump housing 41, is housed within this housing space.

[0075] Furthermore, the motor rotor 21 is intended to be provided with cooling protrusions 47 that project axially from the rear end face. The unique feature here is that these cooling protrusions 47 are located only on the rear end face of the motor rotor 21, and the front end face of the motor rotor 21 does not have such cooling protrusions. This preferably saves axial structural space. The cooling protrusions 47 are configured to each act as a balance weight.

[0076] A pump system comprising a fixed spiral component 11 and a movable spiral component 13 is located at the front end of the pump housing 41. The fixed spiral component 11, also referred to as the spiral housing, is screwed to the front end of the pump housing 41 at its end face and is enclosed by a hood 105, which is similarly attached to the pump housing 41.

[0077] The hood 105 houses a temperature control device for adjusting the operating temperature of the scroll vacuum pump. In one embodiment, the temperature control device is intended to be designed as a fan 95. The fan 95 can operate on a supply voltage of 24V, 48V, or 230V. The operation of the fan 95 is controlled by a control unit 115 of the electronics 45 of the scroll vacuum pump, which will be described in more detail later with reference to Figure 5.

[0078] The movable spiral component 13 is connected to the eccentric portion 19 via a flange bearing 91 configured as a rolling bearing. A pressing disc 93 is located between the axially movable spiral component 13 and the eccentric portion 19. A shim 94 is located between the circumferential shoulder of the drive shaft 17 and the flange bearing 91 at the transition to the eccentric portion 19. Precise circumferential alignment between the fixed spiral component 11 and the pump housing 41 is ensured by a positioning pin 97.

[0079] In Figure 3, the interaction of the internally and externally fitted spiral walls 49, 69, each occupying a semi-circular or crescent-shaped volume in its respective section, is shown. During operation, the gas flowing in through the gas inlet 67, whose position is only indicated in Figure 3, goes to the center of the pump system and, when the exhaust valve 56 is opened at a sufficiently high pressure, through the inlet opening 55 to the outlet channel 59 (see Figure 4). Through the outlet channel 59, the pumped gas goes to the radial outlet 57 and then to the outlet flange 78 when the axial outlet opening 65 is closed by the plug 66, as shown in Figure 4.

[0080] In an alternative configuration, the radial outlet 57 can be closed and the plug 66 removed, thereby forming an axial outlet from the pump system.

[0081] During operation, if overpressure occurs within the pump system, this overpressure can be relieved by relief valves 61b and 63b to avoid excessively high power consumption of the scroll vacuum pump. The uniqueness of this arrangement lies in the fact that multiple, in this case two, bypass channels 61 and 63 are each provided with exactly one relief valve 61b or 63b (see Figure 4). This allows the scroll vacuum pump to achieve a relatively high pumping speed with relatively low power consumption.

[0082] The drawing in Figure 2, showing the Kroll vacuum pump as viewed from the hood 105, allows us to see the arrangement of the inlet flange 77 and the outlet flange 78, respectively. The gas to be pumped enters the pump system, which includes both spiral components 11 and 13, via the inlet flange 77 and is discharged via the outlet flange 78.

[0083] The scroll vacuum pump is equipped with three-phase asynchronous motors 21 and 23 for driving the drive shaft 17. In this embodiment, the diameter of the drive shaft 17 in the region of the sleeve element 33 is 24 mm. In this region, a sleeve element 33 is used that is appropriately sized and pressed against the motor rotor 21 to match the diameter of the drive shaft 17 to the inner diameter of the motor rotor 21. However, a single-phase IPM motor (IPM = embedded permanent magnet) or a synchronous reluctance motor can also be used as a rotational drive for the drive shaft 17. The selection of the drive motor is made in relation to the desired performance, target energy consumption, and customer requirements and application conditions. Such motors, especially IPM motors, demonstrate high efficiency.

[0084] In particular, to balance the rotating system including the drive shaft 17 of the pump system and the movable spiral component 13, the balancing system has a front balance weight 29 and a rear balance weight 31, respectively. In the illustrated embodiment, the rear balance weight 31 is located in front of the rear support point 27. The pressure element 87 for clamping the motor rotor 21 is designed to be rotationally symmetric here.

[0085] The two balance weights 29 and 31 are made of the same material, for example, steel. However, the two balance weights 29 and 31 can also be made of different materials. Thus, according to one aspect of the present invention, the front balance weight 29 is made of brass and the rear balance weight 31 is made of steel.

[0086] The eccentric drive unit, formed by a drive shaft 17 having an eccentric portion 19, is located within the pump housing 41 and is surrounded by a deformable sleeve in the form of a corrugated bellows 89. The corrugated bellows 89 is used, on the one hand, to seal the eccentric drive unit from the suction area of ​​the scroll vacuum pump, and on the other hand, to prevent rotation of the movable spiral component 13. For this purpose, the corrugated bellows 89 is attached to the side of the movable spiral component 13 closer to the drive unit. The rear end of the corrugated bellows 89 is attached to the base of the housing within the pump housing 41 by screws.

[0087] The pump housing 41 is supported on a base formed by the electronics housing 43 (see Figures 1a and 1b). The electronics housing 43 has a housing portion 43a, which has rubber feet 107 on its underside, which are housed in recesses formed on the underside and are in a recessed position in that case.

[0088] The electronics housing 43 houses electronic equipment 45, which includes electronic, electrical, and electromechanical components used, in particular, for powering and controlling the scroll vacuum pump. The pump housing 41 is bolted to the electronics housing 43.

[0089] The efficient operation of the scroll vacuum pump described above, using an IPM motor and based on a dry pump system, has the particular advantage of relatively little heating of the scroll vacuum pump components during operation. In particular, the pump system of the scroll vacuum pump remains relatively cool. This has the advantage of less wear on the components of the scroll vacuum pump compared to other types of pumps, which positively impacts the service life and maintenance costs. The same is true for Roots vacuum pumps.

[0090] However, it was observed that relatively low component temperatures were noticeable when pumping moist gaseous media, particularly those containing a certain amount of water vapor. This is because moist gases tend to condense on the cold surfaces of the pump. In particular, moist media, especially those containing water vapor, were found to condense on the fixed and / or movable helical components 11, 13 near the opening 55, especially in the last two to three helical turns (see Figure 3). Condensation can cause corrosion of pump components and / or the formation of deposits, which will shorten the service life of the scroll vacuum pump.

[0091] Obvious measures to avoid or prevent condensation, such as reducing pump output, negatively affect the vapor capacity of a scroll vacuum pump. However, it is desirable for scroll vacuum pumps to have both the longest possible service life and the highest possible (water) vapor capacity.

[0092] Surprisingly, it was found that the above problem could be solved in a sophisticated way by changing the pump's operating parameters. In particular, the parameters are deliberately selected to be different from the values ​​that are normally set under comparable operating conditions. That is, a special operating mode (condensation avoidance mode) is selected in contrast to normal operation, in which, for example, the operating temperature of the vacuum pump and / or the state of the gas ballast valve are changed compared to normal operation.

[0093] In particular, the operating parameters are modified to increase the temperature of some parts of the pump system in order to reduce the tendency for condensation. Even a relatively small temperature increase can significantly improve (water) vapor resistance and / or (water) vapor capacity.

[0094] Additionally or alternatively, by operating a gas ballast valve (see reference numeral 79), additional dry gas is introduced into the vacuum pump, which increases vapor resistance. Vapor resistance can also be improved by increasing the amount of gas ballast.

[0095] As mentioned earlier, (water) vapor resistance is defined according to ISO 21360. Here, exhaust gas temperature or pump outlet temperature is important. In scroll pumps, the fan is often located near the outlet, so adjusting the fan can directly affect vapor resistance.

[0096] According to one embodiment of the present invention, the aforementioned temperature rise of the scroll vacuum pump is based on a measurement or parameter characterizing the gaseous medium to be conveyed. This measurement may be, for example, the pressure and / or temperature of the medium, the intake pressure of the scroll vacuum pump, the composition of the medium, or the moisture content of the medium. Depending on the application, other parameters may also be included.

[0097] For this purpose, the electronics equipment 45 of the scroll vacuum pump described as an example comprises a detection unit 111, a determination unit 113, and a control unit 115 (see Figure 5), wherein the sensor components of the detection unit 111, not shown in Figure 5, are preferably installed inside the scroll vacuum pump, particularly in the area of ​​the outlet 57 or upstream thereof, and optionally to measure the pressure inside the pump system. Since condensation problems are usually greatest here, it is preferable to determine the characteristic parameters of the medium inside the pump system (e.g., the opening 55 and adjacent areas).

[0098] The detection unit 111 is provided to determine the aforementioned characteristic parameters of the medium. To measure the intake pressure of the scroll vacuum pump, the detection unit 111 may include, for example, at least one pressure sensor (not shown) preferably located at the gas inlet 67 (see Figure 3).

[0099] To measure the pressure of the medium, the detection unit 111 may additionally or alternatively include a piezoelectric pressure sensor for measuring a first pressure value independent of the moisture content of the medium, and at least one Pirani pressure sensor for measuring a second pressure value dependent on the humidity of the medium. The piezoelectric pressure sensor is a piezoresistive and / or piezoelectric pressure sensor.

[0100] The determination unit 113 is provided to determine the moisture characteristic value based on the difference between the pressure value measured by the piezoelectric pressure sensor and the pressure value measured by the Pirani pressure sensor. The moisture characteristic value is a measure of the humidity of the medium, in particular the water vapor content in the medium.

[0101] Optionally, the determination unit 113 is configured to determine a moisture characteristic value as an indicator of moisture in the intake gas / gas mixture, based on the consistently high intake pressure measured by the pressure sensor of the detection unit 111. In this method of determining the moisture characteristic value, for example, the operating temperature of the pump and / or the temperature and / or (molecular) composition of the gas are also taken into consideration.

[0102] The techniques described above for determining moisture content can be combined to obtain the most accurate results possible.

[0103] The piezo pressure sensor 119 and the Pirani pressure sensor 121 may be part of a measuring device 117 schematically shown in Figure 6 for determining the humidity of a medium, particularly the water vapor content in a gaseous medium.

[0104] Furthermore, the measuring device 117 includes an evaluation unit 123 that determines the moisture characteristic value based on the difference between the pressure value measured by the piezo pressure sensor 119 and the pressure value measured by the Pirani pressure sensor 121.

[0105] Furthermore, the measuring device 117 is equipped with a communication interface (not shown) for exchanging data with external devices such as electronic equipment 45. In particular, the evaluation unit 123 is provided to transmit moisture characteristic values ​​to the control unit 115. That is, the measuring device 117 can perform the functions of the detection and determination units 111 and 113.

[0106] Optionally, the pressure sensor 119 of the measuring device 117 can be used to detect the suction pressure of the pump. As a result, only one pressure measuring device is required.

[0107] Pressure measurements in the intake region, exhaust region, and / or inside the pump system may be performed by separate pressure sensors.

[0108] The control unit 115 may automatically switch the scroll vacuum pump to condensation avoidance mode if the moisture characteristic value falls below or exceeds a predetermined threshold. In this case, the operating temperature of the pump is raised by, for example, about 5°C to 15°C by reducing the speed of the fan 95, resulting in no condensation occurring inside the pump and no increase in the pump's vapor capacity. In particular, it has been found that even with this relatively small temperature increase, the vapor capacity of the scroll vacuum pump can increase by up to 100%. At the same time, the scroll vacuum pump remains very cold in condensation avoidance mode, and pump wear remains low.

[0109] To ensure that the scroll vacuum pump does not overheat, the control unit 115 is also configured to increase the speed of the fan 95 again if the pump's operating temperature exceeds a predetermined threshold. This measure can be implemented as part of a condensation avoidance mode, thus providing a balanced solution between condensation avoidance and pump protection.

[0110] Furthermore, the control unit 115 is configured to automatically start the scroll vacuum pump in condensation avoidance mode if condensation occurs, for example, while the pump is stopped. If the vacuum pump does not have the necessary sensors, the condensation mode can also be activated manually or by the user.

[0111] Furthermore, the control unit 115 is configured to automatically switch the scroll vacuum pump from condensation avoidance mode to normal operation mode when the moisture characteristic value does not fall below or exceed a predetermined threshold, or when, based on experience, a sufficient amount of time has elapsed to remove moist gas from the recipient to be exhausted.

[0112] Furthermore, the scroll vacuum pump may be configured to allow manual switching to a condensation avoidance mode during normal operation or when the pump is switched off. This can be done by activating the pump's human-machine interface.

[0113] Pump temperature adjustment can also be performed by considering the operating parameters of the pump itself.

[0114] For this purpose, the scroll vacuum pump may include a measuring unit (not shown) provided to detect at least one operating parameter of the vacuum pump. Thus, the control unit 115 is provided to operate the scroll vacuum pump in condensation avoidance mode based not only on moisture characteristic values ​​but also on the operating parameter of the scroll vacuum pump. This parameter may be temperature, in particular the temperature of a part of the pump system (e.g., the temperature of components 11 and / or 13).

[0115] The detection unit 111 and / or the measuring unit includes a moisture sensor (not shown) for measuring the amount of moisture on the surface of a medium or part of the pumping system of a scroll vacuum pump. The determination unit 113 is then configured to also determine moisture characteristic values ​​based on the measured moisture.

[0116] Figure 1c shows a cross-sectional view BB of the area of ​​a scroll vacuum pump where a gas ballast valve 79 is located. The gas ballast valve 79 shown on the left is provided with a closing cover 81. However, the gas ballast valve 79 shown on the right has a rotary knob 82 for adjustment.

[0117] The control unit 115 may be configured to automatically operate the gas ballast valve 79 in condensation avoidance mode in order to increase the steam capacity of the scroll vacuum pump. However, the gas ballast valve 79 may also be configured to be operated manually in condensation avoidance mode.

[0118] The speed of the fan 95 and the operation of the gas ballast valve 79 may be controlled individually or in combination, as needed.

[0119] Depending on the embodiment, the measures described above can be implemented with little to no additional components, or by simple structural measures, and in some cases by software updates alone. In some cases, existing systems can also be easily improved. [Explanation of Symbols]

[0120] 11 Fixed spiral components, spiral housing 13. Movable spiral parts, orbital 15. Axis of rotation 17 Drive shaft 17a Shoulder 19 Eccentric part 21 Motor Rotor 23 Motor Stator 25 Front bearing location (fixed bearing) 27 Rear bearing location (free bearing) 29 Front balance weight 31 Rear balance weight 33 Sleeve Elements 38 screws 39. Balance part of the rear balance weight 41 Pump Housing 43 Electronics Housing 45 Electronics Equipment 47 Cooling protrusion 49 Spiral wall of fixed spiral component 55 Inflow opening 56 Exhaust valve 57 Exit 59 Exit Channels 61 Bypass Channel 61a Bypass opening 61b Relief valve 63 Bypass Channels 63a Bypass opening 63b Relief valve 63c aperture 65 Axial exit opening 66 stoppers 67 Gas inlet of pump system 69 Spiral wall of movable spiral parts 77 Inlet flange 78 Outlet flange 79 Gas ballast valve 81 Gas ballast valve closing cover 82 rotary knobs 83. Center screw 85 Positioning elements, positioning pins 87 Pressure elements 89. Wavy bellows 91 Flange bearing 93 Pressure disc 94 Sims 95 Fans 97 Positioning pins 99 Wave Spring 101 Radial intrusion as a marking 103 Motor Cover 105 Food 107 Legs 111 Detection Unit 113 Decision Unit 115 Control Unit 117 Measuring device 119 Piezoelectric pressure sensor 121 Pirani pressure sensor 123 evaluation units

Claims

1. A vacuum pump for transporting a gaseous medium, particularly a vacuum pump for dry operation, The vacuum pump in question is, A pump system having at least one gas inlet (67) and at least one outlet (57), A detection unit (111) provided and configured to detect at least one characteristic parameter of a medium, A determination unit (113) provided and configured to determine a moisture characteristic value, which is a measure of the humidity of a medium, particularly the water vapor content in the medium, based on at least one characteristic parameter and / or the time course of at least one characteristic parameter, and A control unit (115) provided and configured to operate the vacuum pump in a condensation avoidance mode, which affects at least one operating parameter of the vacuum pump, in particular the operating temperature of the vacuum pump and / or the state of the gas ballast valve (79) of the vacuum pump, in order to increase the vapor capacity of the vacuum pump. A vacuum pump equipped with the following features.

2. A vacuum pump for transporting a gaseous medium, preferably the vacuum pump described in claim 1, and more particularly a dry-operation vacuum pump, The vacuum pump in question is, A pump system having at least one gas inlet (67) and at least one outlet (57), A control unit (115) provided and configured to operate the vacuum pump in a condensation avoidance mode, which affects at least one operating parameter of the vacuum pump, in particular the operating temperature of the vacuum pump and / or the state of the gas ballast valve (79) of the vacuum pump, in order to increase the vapor capacity of the vacuum pump. In the vacuum pump comprising, The control unit (115) includes an operating means that allows the vacuum pump to be manually changed to a condensation avoidance mode. Vacuum pump.

3. The values ​​of the operating parameters of the vacuum pump in condensation avoidance mode are different from the values ​​of the operating parameters in normal operation of the vacuum pump. The vacuum pump according to claim 1 or 2.

4. The control unit (115) is provided and configured to change the vacuum pump to a condensation avoidance mode when the moisture characteristic value falls below or exceeds a predetermined threshold. The vacuum pump according to claim 1 or 3.

5. The control unit (115) is provided and configured to adjust at least one operating parameter of the vacuum pump based on moisture characteristic values. A vacuum pump according to at least one of claims 1, 3, and 4.

6. The control unit (115) is provided and configured to, in condensation avoidance mode, keep at least one operating parameter of the vacuum pump constant over time, or to change it according to a fixed scheme. A vacuum pump according to at least one of claims 1, 3 to 5.

7. The system further comprises a measuring unit provided and configured to detect at least one operating parameter of the vacuum pump, The control unit (115) is provided and configured to operate the vacuum pump in condensation avoidance mode based on the moisture characteristic value and the operating parameters of the vacuum pump. A vacuum pump according to at least one of claims 1 to 6.

8. The detection unit (111) includes at least a pressure measuring device for measuring the pressure of the medium. A vacuum pump according to at least one of claims 1, 3 to 7.

9. The detection unit (111) includes at least one pressure sensor, preferably located at the gas inlet (67), for measuring the intake pressure of the vacuum pump. The determination unit (113) is provided and configured to determine moisture characteristic values ​​based on the time course and / or amount of intake pressure. A vacuum pump according to at least one of claims 1, 3 to 8.

10. The detection unit (111) and / or measurement unit comprises at least one moisture sensor for measuring the moisture content of the medium or the surface of the vacuum pump, The determination unit (113) is provided and configured to determine moisture characteristic values ​​based on the measured moisture content. A vacuum pump according to at least one of claims 1, 3 to 9.

11. The vacuum pump further comprises a temperature control device, preferably located at the outlet (57), for influencing the operating temperature of the vacuum pump, in particular a fan and / or heating element. The control unit (115) is provided and configured to control the temperature control device and thereby affect the operating temperature of the vacuum pump, particularly to increase the operating temperature. A vacuum pump according to at least one of claims 1 to 10.

12. Controlling the temperature control device includes reducing the speed of the temperature control device to a particularly low 10% to 60%, particularly low 20% to 50%, particularly low 30% to 40% of the maximum speed of the temperature control device, or preferably switching off the temperature control device for a limited period of time. The vacuum pump according to claim 11.

13. The vacuum pump comprises at least one controllable gas ballast valve (79) that can be controlled by the control unit (115). A vacuum pump according to at least one of claims 1 to 12.

14. Preferably, a measuring device (117) for determining the humidity of a gaseous medium, particularly the water vapor content, for a vacuum pump that transports a gaseous medium, as described in at least one of claims 1 to 13, The measuring device (117) is At least one piezoelectric pressure sensor (119), in particular at least one piezoelectric pressure sensor and / or at least one piezoelectric resistance pressure sensor, At least one Pirani pressure sensor (121) and An evaluation unit (123) is provided and configured to determine a moisture characteristic value, which is a measure of the humidity of a medium, particularly the water vapor content in the medium, based on the difference between a first pressure value measured by the piezoelectric pressure sensor (119) and a second pressure value measured by the Pirani pressure sensor (121). Equipped with, Measuring device (117).

15. A vacuum pump for transporting a gaseous medium, in particular a method for operating a vacuum pump for transporting a gaseous medium as described in at least one of claims 1 to 14, A step of detecting at least one characteristic parameter of a medium, A step of determining a moisture characteristic value, which is a measure of the humidity of a medium, particularly the water vapor content in the medium, based on at least one characteristic parameter and / or the time course of at least one characteristic parameter, and A step of operating the vacuum pump in a condensation avoidance mode, which affects at least one operating parameter of the vacuum pump, in particular the operating temperature of the vacuum pump and / or the state of the gas ballast valve (79) of the vacuum pump, in order to increase the vapor capacity of the vacuum pump. Methods that include...

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