Eccentric screw pump, metering system and method
Patent Information
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- VISCOTEC PUMPEN & DOSIERTECHN GMBH
- Filing Date
- 2024-07-24
- Publication Date
- 2026-05-06
Smart Images
Figure EP2024070952_27022025_PF_FP_ABST
Abstract
Description
[0001] Progressive screw pump, dosing system and process
[0002] The present invention relates to an eccentric screw pump, a dosing system with at least two such eccentric screw pumps and a method for operating such an eccentric screw pump.
[0003] Impregnating the rotor and stator is an important process in electric motor manufacturing. Particularly with the electrification of the automotive powertrain, the demand for durable electric motors with maximum power density and low noise emissions is increasing. The quality of the insulation in electric drives determines, among other things, the longevity and efficiency of the electric drive. The round or flat wire required for the coil is first coated with a layer of varnish to ensure electrical insulation. A sliding layer is then applied to the round wire to facilitate winding.
[0004] After the round wire is wound or the flat wire is joined, impregnation is carried out to create secondary insulation. For this purpose, a potting compound, for example in the form of an impregnating resin, is applied to the wire to fill cavities within the windings or between the winding and the core, and to displace air bubbles. It is important that the potting compound has a low viscosity and is continuously metered without air inclusions. This is the only way for the potting compound to penetrate optimally into all cavities. The temperature during processing of the potting compound is a process-determining parameter that – in conjunction with the component – must be matched to the respective material.
[0005] Secondary insulation increases the durability of rotating electrical machines, especially electric motors and generators. By closing and sealing the cavities, vibrations are minimized. These could otherwise lead to short circuits and noise. Mechanical resistance is thus increased. As already mentioned, the impregnation also serves the purpose of displacing air pockets. Air is a good thermal insulator and would hinder the desired heat dissipation. If these air pockets are filled with the potting compound, a complete thermal coupling is created between the laminated core and the windings. The heat can be optimally dissipated.
[0006] In high-voltage applications, air can also cause electrical breakdown. Encapsulation with the potting compound further improves electrical insulation within the windings and prevents short circuits caused by damage to the coating. The potting compound also provides protection against chemical influences, moisture, and dust. Overall, impregnation can result in a longer service life and improved performance.
[0007] Based on in-house experience, various impregnation methods can be used. First, the component to be impregnated can be immersed in the potting compound. This involves immersing the preheated component into a potting compound basin at a defined speed. The potting compound can gel due to the heating of the component during the immersion process. This, in turn, can reduce drip losses. In the so-called roll immersion process, the component also rotates during and after the immersion process. The component is then cured in a heating section. Immersion can be adapted to any size, resulting in low investment costs if rotation of the component is eliminated, and immersion is easily scalable for large volumes.
[0008] Secondly, vacuum encapsulation using the potting compound is possible. Here, the stator is clamped into a mold, into which the potting compound flows and slowly rises. A sealing core is placed in the center of the stator to ensure vacuum tightness. The entire mold or component is evacuated. The evacuated potting compound is introduced under vacuum. Air pockets and cavities are reliably sealed, and copper windings, undercuts, and gaps are completely filled with the potting compound. After the potting compound has cured, the sealing core is removed. The advantage of vacuum encapsulation is the avoidance of cavities and a high impregnation quality. Furthermore, the use of two-component potting compounds is possible.
[0009] Thirdly, trickling the potting compound is possible. In this method, the component or stator is clamped onto a mandrel and continuously rotated around its own axis in a horizontal orientation. The component is heated by furnace heating or by induction. During rotation, the low-viscosity potting compound is dripped onto the component through several nozzles at various positions using a dosing system. Due to capillary action, the potting compound penetrates the windings and is evenly distributed throughout the stator. This results in a high-quality impregnation result. Trickling is particularly suitable when only specific areas of the component are to be wetted with the potting compound.
[0010] The advantages of trickling are that the dosage quantity and flow rate can be precisely controlled. This allows for low consumption of the potting compound with a high fill level. Trickling is ideal for the application of two-component potting compounds. It enables rapid curing and / or crosslinking at low temperatures. This, in turn, reduces investment and operating costs. The defined consumption of the potting compound results in a clean processing process. Contamination of the dispensing system is avoided. One-component or two-component, cold-curing or heat-curing epoxy resin systems and polyester resin systems can be used as potting compounds or impregnation materials. The aforementioned materials are low-viscosity, allowing them to flow into every cavity, even in narrow sections of the windings. Most potting compounds are thermally curing.Typical properties of such casting compounds are good electrical insulating properties and high creep ability.
[0011] One-component casting compounds have the advantage of being particularly robust and requiring no mixing. They are suitable for both trickling and dipping. The investment for a dosing system for conveying a one-component casting compound is significantly lower than for a two-component casting compound. Curing is achieved through the use of thermal energy and can require long heating sections.
[0012] Two-component casting compounds combine several advantages. They have a short curing time, which in turn requires a shorter heating section. This ultimately means lower investment costs and, above all, lower energy costs in production. They also have a precisely defined curing time and better storage stability. After curing, the casting compound becomes a hard, elastic molding material. The disadvantage is a more complex processing process. This is due to the required dosing parameterization for different mixing ratios and the selection of the appropriate static mixer.
[0013] Progressive cavity pumps, in particular, are used for impregnating electric motors by trickling. The operation of such a progressing cavity pump is based on the endless piston principle. A rotor, which can be made of stainless steel, performs an eccentric rotational movement within a stator made of an elastomer. The resulting conveying chambers within the progressing cavity pump form a defined volume. A precise amount of a medium to be metered, such as the potting compound, is metered per revolution. Due to the proportionality between drive speed and discharge rate, the metering volume and speed can be easily regulated. Should the process parameters change due to a component or material change, both the metering volume and speed can be easily and quickly adjusted using a control system on the progressing cavity pump.
[0014] The trickling of two components requires precise coordination and calibration of two progressing cavity pumps and the correct selection of a static mixer. Both components are conveyed completely separately until they enter the static mixer. This prevents unwanted hardening before reaching the static mixer. The correct selection of the static mixer is crucial for good mixing.
[0015] Progressing cavity pumps operate with low shear, valveless, and pulsation-free performance. Consistent, pulsation-free dosing is a key prerequisite for high-quality trickling results. Varying viscosities, thixotropic properties, high solids content, and highly reactive dosing materials require extremely careful handling. The endless piston principle is pressure-stable and viscosity-independent, offering exceptionally high dosing accuracy.
[0016] In addition to dosing, the extraction and, if necessary, preparation of the media to be dosed must also be considered. Since the impregnation result must be bubble-free, it is recommended to treat the material with a preparation system, such as a degassing system, before the dosing process. However, the chemical and rheological properties must remain unchanged. Sedimentation cannot be ruled out with filler-laden casting compounds. This can be prevented with a suitable agitator or a circulation process.
[0017] Furthermore, it is also important to note that sealing elements of the eccentric screw pump, which, for example, radially seal a rotor unit containing the rotor, should neither be undermined by the casting compound nor chemically attacked by it in order to achieve the longest possible service life of these sealing elements.
[0018] Against this background, one object of the present invention is to provide an improved eccentric screw pump.
[0019] Accordingly, an eccentric screw pump for metering a medium is proposed. The eccentric screw pump comprises at least two stators, at least two rotor units, wherein, during operation of the eccentric screw pump for metering the medium, each of the at least two rotor units interacts with one of the at least two stators, a pump housing to which the at least two stators are attached and through which the at least two rotor units extend at least partially, wherein the pump housing has a tank portion for receiving the medium, and at least two sealing devices for sealing the at least two rotor units relative to the tank portion, wherein the at least two sealing devices are arranged outside the tank portion.
[0020] Because the sealing device is arranged outside the tank section, the sealing device does not come into contact with the medium to be metered. This reliably prevents damage to the sealing device, particularly in the case of chemically aggressive media. Furthermore, infiltration of the sealing device by the medium is also prevented. The stator preferably has a tubular stator outer part and a stator inner part received in the stator outer part. The stator outer part can, for example, be firmly connected to the pump housing. Alternatively, the stator outer part can also be part of the pump housing. The stator inner part is preferably made of an elastomer. The stator inner part has, in particular, a helical or spiral-shaped inner geometry or inner contour. For this purpose, the stator inner part has, in particular, an opening with a helical or spiral-shaped inner geometry or inner contour.The inner stator part is connected to the outer stator part in a rotationally fixed manner. The inner stator part is, in particular, replaceable. The outer stator part can also be replaceable. The inner stator part is, in particular, arranged within the outer stator part. The inner stator part can also be arranged, at least in sections, within the pump housing. However, the inner stator part is preferably located entirely outside the tank section.
[0021] The rotor unit preferably comprises a drive shaft driven by the drive of the eccentric screw pump. In addition to the drive shaft, the rotor unit comprises, in particular, a rotor having a helical or screw-shaped outer geometry or outer contour that interacts with the helical or screw-shaped inner contour of the stator, in particular the inner part of the stator, to meter the medium. The rotor can be made of a metallic material, for example, stainless steel, or of a suitable plastic material.
[0022] A flex shaft is provided between the rotor and the drive shaft, which connects the rotor to the drive shaft. The flex shaft is placed between the drive shaft and the rotor along a longitudinal direction of the rotor unit, which is oriented from the drive shaft towards the rotor and parallel to an axis of symmetry of the rotor unit. The flex shaft can also be referred to as a flexible shaft. The flex shaft is preferably elastically deformable and enables eccentric movement of the rotor in the stator, in particular in the inner stator part of the stator. The flex shaft serves to transmit torque from the drive shaft to the rotor. The flex shaft can be a wire rope, which is coated or sheathed, for example, with a plastic material. The flex shaft is connected in a rotationally fixed manner to the drive shaft and in a rotationally fixed manner to the rotor.
[0023] As the rotor rotates within the stator, particularly within the inner stator section, the medium to be metered is pumped longitudinally away from the drive shaft according to the endless piston principle through the interaction of the rotor with the stator, particularly with the inner stator section. The delivery volume per unit of time depends on the speed, size, pitch, and geometry of the rotor. Thus, the eccentric screw pump enables highly precise metering processes with a high degree of repeatability.
[0024] The rotor is firmly connected to the drive shaft by means of the flexible shaft. The rotor is located at the front of the flexible shaft and interacts with the stator, in particular with the inner stator part. The rotor is helical or spiral-shaped. The term "helical" or "spiral-shaped" in this context means, in particular, that the rotor has the aforementioned helical or spiral-shaped outer contour. The terms "helical" and "spiral-shaped" are interchangeable. During operation of the eccentric screw pump, the rotor interacts with the stator, which, in particular, has the aforementioned opening on or in the inner stator part in which the rotor is arranged. A "flexible shaft" in this context is understood to mean a shaft, in particular generally a component, that allows eccentric movement of the rotor relative to the drive shaft.For this purpose, the flexible shaft can, for example, have a joint, in particular a universal joint or a cardan joint, or several joints. The flexible shaft can also be referred to as a flexible shaft or cardan shaft. However, the flexible shaft itself is particularly preferably elastically deformable. However, it is not absolutely necessary for the flexible shaft itself to be flexibly deformable. The flexible shaft can also be a bending rod, in particular a plastic bending rod, or be referred to as such. In this case, the flexible shaft can be made, for example, from a polyetheretherketone (PEEK), polyethylene (PE) or the like. However, the flexible shaft is particularly preferably made from a steel cable, in particular a plastic-coated one. In particular, the steel cable can be elastomer-coated. Examples of elastomers that can be used include fluororubbers (FKM) or perfluororubbers (FFKM).
[0025] The medium to be dispensed can be, for example, an adhesive or sealant, water, an aqueous solution, a paint, a suspension, a viscous raw material, an emulsion, or a grease. The medium can be liquid. For example, the medium can contain fillers, such as so-called microballoons, fibrous, particularly short-fiber, components, or the like. In particular, the medium can be an adhesive, such as a cyanoacrylate. In particular, the medium is low-viscosity and / or self-leveling.
[0026] The medium is particularly preferably a casting compound, in particular an impregnating resin. For example, the medium can be a cold-curing or heat-curing one-component or two-component epoxy resin system or polyester resin system. The medium can be self-leveling at a viscosity of approximately 500 to 3,000 mPa, in particular 1,500 to 2,000 mPa. For example, the medium can react and / or cure at a temperature of 25°C or higher.
[0027] The pump housing is preferably arranged such that the stator is located below the sealing device, viewed along a direction of gravity. The tank section is also located below the sealing device. The tank section of the pump housing serves to receive or store the medium. Accordingly, the terms "receive" and "store" can be interchanged arbitrarily. The tank section can also be referred to as a receiving section or a storage section. A "tank section" is understood here to be an area or section of the pump housing through which the medium not only flows or is passed, but which is designed to receive and / or store the medium. A defined or predetermined volume of the medium is thus held in the tank section.For example, 400 ml of medium is stored in the tank section and pumped out of the tank section with the help of the rotor and stator. A particularly consistent or constant fill level of the medium can be established in the tank section. The sealing device is always arranged above the fill level, viewed along the direction of gravity. The tank section has a hollow body-shaped geometry. In particular, the tank section is a hollow body. The tank section can be cuboid-shaped, particularly cube-shaped. The tank section can also be cylindrical or tubular. In principle, the tank section can have any desired geometry.
[0028] The stator and the rotor are arranged, in particular, outside the tank section. The rotor unit preferably runs centrally through the tank section. In particular, the rotor is arranged outside the tank section, with the flexible shaft being placed, in particular, inside the tank section. The drive shaft of the rotor unit can also be arranged, at least in sections, inside the
[0029] The tank section encloses or delimits an interior space in which the medium is contained. The tank section can have a tubular or hollow-cylindrical geometry.
[0030] The fact that the sealing device "seals" the rotor unit from the tank section means, in this case, in particular that the sealing device prevents the medium from escaping from the tank section along the rotor unit. In particular, the sealing device bears radially against the rotor unit in a sealing manner. The sealing device can be mounted in or on the pump housing or on a part of the pump housing. Preferably, however, a seal housing is provided for the sealing device. The seal housing can be connected to the pump housing. The seal housing can also be part of the pump housing.
[0031] The fact that the sealing device is arranged "outside" the tank section means in particular that the sealing device is not located inside the tank section and is therefore not covered or wetted by the medium. In particular, the sealing device is always arranged above the fill level of the medium in the tank section. This is achieved by orienting the rotor unit along the direction of gravity. The fill level can also be referred to as the liquid level or medium level. Accordingly, the terms "fill level," "liquid level," and "medium level" can be interchanged as desired. The sealing device can be spatially separated from the tank section by means of the seal housing. This means that the seal housing can be arranged in sections between the sealing device and the tank section, in particular the interior of the tank section.According to one embodiment, the eccentric screw pump further comprises a fill level sensor which is configured to continuously detect a fill level of the medium within the tank section.
[0032] Preferably, the fill level sensor is an analog sensor and detects a fill level of the medium within the tank section with a value of 0 to 100%. The fill level can be detected in real time. With the help of the fill level sensor, continuous monitoring of the fill level of the medium within the tank section is possible. If the fill level drops, for example, the medium can be refilled into the tank section. It is possible, for example, to refill the medium into the tank section in such a way that the fill level of the medium within the tank section remains constant. The medium can also only be refilled when a minimum fill level of the medium is reached in the tank section. The fill level sensor can be attached to the seal housing.
[0033] According to a further embodiment, the tank section is formed by a cross-sectional enlargement of the pump housing.
[0034] In this context, a "cross-sectional enlargement" is understood in particular to mean that the pump housing widens or expands in the area of the tank section. For example, the tank section has a larger diameter, in particular a larger inner diameter, than the rest of the pump housing.
[0035] According to a further embodiment, an inner diameter of the tank section is larger than an outer diameter of the stator.
[0036] In particular, the inner diameter of the tank section is larger than an outer diameter of the stator outer part. Particularly preferably, the inner diameter of the tank section is a multiple of the outer diameter of the stator.
[0037] According to a further embodiment, the inner diameter is at least twice as large as the outer diameter.
[0038] Particularly preferably, the inner diameter can be at least three times the outer diameter. However, the inner diameter of the tank section is particularly preferably at least twice the outer diameter of the stator, in particular the outer stator part.
[0039] According to a further embodiment, the pump housing has a flange section and a transition section connecting the tank section and the flange section, wherein the transition section is funnel-shaped.
[0040] The transition section is thus arranged between the tank section and the flange section. The tank section and the flange section preferably each have a tubular or hollow-cylindrical geometry, with the tank section having a larger diameter than the flange section. Preferably, an outer diameter of the flange section is identical to the outer diameter of the stator. The funnel-shaped design of the transition section reliably ensures that the medium flows from the tank section toward the flange section. A remaining dead volume of medium within the tank section is thus reliably prevented.
[0041] According to a further embodiment, the stator is attached to the flange section. For example, the outer stator part can be clamped or screwed to the flange section. The inner stator part can extend into the flange section, at least in sections. The inner stator part can be secured against rotation relative to the outer stator part by means of anti-rotation devices.
[0042] According to a further embodiment, the eccentric screw pump further comprises an inlet projecting into the tank section for filling the medium below the level.
[0043] In this context, "below-level filling" means that the medium flowing into the tank section is introduced below the fill level of the medium present in the tank section. This reliably prevents the formation of bubbles in the medium when refilling the tank section. The inlet can be mounted on the seal housing.
[0044] According to a further embodiment, the eccentric screw pump further comprises a seal housing connected to the pump housing, wherein the sealing device is accommodated in the seal housing.
[0045] The seal housing can, for example, be screwed to the pump housing. The seal housing preferably comprises a receiving section, which can be groove-shaped. The sealing device can be accommodated in the receiving section. The rotor strand is guided centrally through the seal housing. For this purpose, the seal housing can have a central opening or bore. According to a further embodiment, the sealing device has at least one sealing sleeve, wherein the rotor unit has a protective sleeve, and wherein the at least one sealing lip rests against the protective sleeve.
[0046] The sealing device can preferably have a sealing element that comprises at least one sealing lip. For example, the sealing element can have two such sealing lips. The sealing lips can be elastically deformed. Furthermore, the sealing device can have an O-ring that is arranged in a groove of the sealing element. With the help of the O-ring, the sealing element can be sealed against the receiving section. The protective sleeve is preferably easily replaceable in the event of wear. The protective sleeve encloses at least part of the drive shaft of the rotor unit. The protective sleeve is tubular or hollow-cylindrical.
[0047] According to a further embodiment, the eccentric screw pump further comprises a drive for driving the rotor unit, wherein the drive is coupled to the rotor unit by means of a coupling star, and wherein the coupling star is made of a heat-insulating material.
[0048] The coupling star can be made of a plastic material, for example. The coupling star prevents heat from the drive from being introduced into the rotor unit. This prevents heating of the rotor unit and thus unwanted heating of the medium and thus hardening and / or crosslinking of the same on the rotor unit. The drive can comprise an electric motor. Preferably, the rotor unit is rigidly connected to a bearing shaft, which is mounted in a bearing housing of the eccentric screw pump by means of a bearing. The bearing housing, in turn, can be connected to the seal housing. The bearing shaft is coupled to a shaft coupling of the drive by means of the coupling star. The coupling star serves to transmit torque. According to a further embodiment, the eccentric screw pump further comprises a temperature sensor for monitoring the temperature of the sealing device.
[0049] For this purpose, a bore is provided in the area of the sealing device, for example, in which the temperature sensor is accommodated. The temperature sensor can thus be mounted on the seal housing. The temperature sensor can be used to detect, for example, temperature-related damage or aging of the sealing device, so that it can be replaced early.
[0050] According to a further embodiment, the eccentric screw pump further comprises a thermal insulation and / or heating sleeve which encloses the pump housing at least in sections.
[0051] The thermal insulation and / or heating sleeve can be used to prevent heat from entering the pump housing, particularly the tank section, and thus the medium. In this case, the thermal insulation and / or heating sleeve acts purely as a thermal insulation sleeve. This prevents the medium from reacting and / or hardening. The thermal insulation and / or heating sleeve can be made, for example, from a plastic material, glass wool, perlite, or the like. The thermal insulation and / or heating sleeve can enclose the tank section and the stator. The thermal insulation and / or heating sleeve can be removable. Heat can also be introduced into the tank section using the thermal insulation and / or heating sleeve. In this case, the thermal insulation and / or heating sleeve functions as a heating sleeve. Active temperature control of the medium can be achieved.The temperature of the medium can be measured, allowing a control loop to be implemented using the thermal insulation and / or heating sleeve. The thermal insulation and / or heating sleeve can also serve both as thermal insulation and as heating.
[0052] According to a further embodiment, the eccentric screw pump further comprises an overfill sensor for monitoring a maximum fill level of the medium in the tank section.
[0053] The overfill sensor can thus reliably prevent overfilling of the tank section. In particular, it can also prevent the medium from rising to the sealing device and coming into contact with it. The overfill sensor can be mounted on the seal housing.
[0054] According to a further embodiment, the eccentric screw pump further comprises a valve for venting or de-venting the tank section, for applying a vacuum to the tank section and / or for supplying the tank section with a process gas, such as nitrogen, argon or the like.
[0055] Multiple valves can be provided. The process gas is an inert gas. The valve is preferably mounted on the seal housing. The valve can be used, for example, to vent the medium to remove air bubbles.
[0056] According to a further embodiment, the eccentric screw pump further comprises an end piece unit attached to the stator, comprising a temperature-pressure sensor. The end piece unit can be connected to the stator, in particular to the outer part of the stator, for example, by means of a union nut. The end piece unit can comprise a hose connection or can be a hose connection. The end piece unit preferably comprises an end piece, which is fastened to the stator by means of the aforementioned union nut, and a hose connection element, which can be screwed into the end piece. The combined temperature-pressure sensor is attached to the end piece unit, in particular to the end piece. With the aid of the temperature-pressure sensor, the temperature and / or pressure of the medium exiting the stator can be determined. This can be used to regulate dosing.
[0057] The eccentric screw pump has at least two stators, at least two rotor units, wherein during operation of the eccentric screw pump for metering the medium each of the at least two rotor units cooperates with one of the at least two stators, wherein the at least two stators are attached to the pump housing, and wherein the at least two rotor units extend at least partially through the pump housing, and at least two sealing devices for sealing the at least two rotor units with respect to the tank section, wherein the at least two sealing devices are arranged outside the tank section.
[0058] This arrangement has the advantage that multiple dosing points can be operated with a common pump housing. The number of stators, rotor units, and sealing devices is unlimited. Other components, such as drives, are also present in multiples. Each rotor unit is assigned a sealing device.
[0059] According to a further embodiment, the pump housing comprises several detachably connected pump housing modules. The pump housing thus has a modular design. The pump housing can therefore also be referred to as a modular pump housing. Any number of pump housing modules can be used. The pump housing modules can be locked and / or screwed together.
[0060] Furthermore, a dosing system for dosing a medium is proposed. The dosing system comprises at least two such eccentric screw pumps, a ring line to which the at least two eccentric screw pumps are connected and through which the medium flows continuously, and a medium supply for supplying the ring line with the medium.
[0061] The number of eccentric screw pumps is optional. For example, the dosing system can also have three, four, or more than four such eccentric screw pumps. The medium circulates in the ring line at a pressure of, for example, 2 bar to 4 bar, especially 3 bar. A pump can be provided that pumps the medium through the ring line. The medium supply can be a tank that supplies the ring line with the medium.
[0062] According to one embodiment, the at least two eccentric screw pumps are connected to the ring line by means of inlet lines, wherein each inlet line is assigned a valve.
[0063] The valves can be used to meter the medium flowing through the supply lines. For example, the valves can be used to maintain a constant or consistent fill level of the medium in each tank section of each progressing cavity pump. The valves can be diaphragm valves or designated as such. Accordingly, the terms "valve" and "diaphragm valve" can be interchanged here. However, any other valve can also be used as a valve. For example, electric ball valves can also be used as valves. In particular, the medium is always metered down to a predetermined minimum fill level in the tank section, and then the medium is refilled into the tank section via the respective valve.
[0064] Furthermore, a method for operating such an eccentric screw pump is proposed. The method comprises the following steps: a) dosing the medium using the eccentric screw pump, and b) maintaining a fill level of the medium in the tank section by supplying the medium to the tank section during step a).
[0065] As previously mentioned, the medium can be supplied to the tank section, for example, via the inlet lines of the dosing system. During step b), the medium can be supplied in such a way that the fill level of the medium in the tank sections of the eccentric screw pumps remains constant. However, the fill level can also change. Particularly preferably, the medium is metered until a minimum fill level of the medium is reached in the tank section. As soon as the minimum fill level is reached, medium is supplied to the tank section again.
[0066] According to one embodiment, temperature detection and pressure detection of the medium are carried out during step a).
[0067] Temperature and pressure detection can be performed, for example, at the end piece of the eccentric screw pump. Furthermore, temperature detection can also be performed using the temperature sensor of the sealing device. The embodiments and features described for the proposed eccentric screw pump apply accordingly to the proposed dosing system and / or the proposed method, and vice versa.
[0068] "One" in this case is not necessarily limited to a single element. Rather, multiple elements, such as two, three, or more, may also be included. Any other counting term used here should not be understood as implying a limitation to the exact number of elements stated. Rather, numerical deviations, both upward and downward, are possible unless otherwise stated.
[0069] Further possible implementations of the eccentric screw pump, the dosing system, and / or the method also include combinations of features or embodiments described above or below with regard to the exemplary embodiments that are not explicitly mentioned. In this case, the person skilled in the art will also add individual aspects as improvements or additions to the respective basic form of the eccentric screw pump, the dosing system, and / or the method.
[0070] Further advantageous embodiments and aspects of the eccentric screw pump, the dosing system, and / or the method are the subject of the dependent claims and the exemplary embodiments of the eccentric screw pump, the dosing system, and / or the method described below. The eccentric screw pump, the dosing system, and / or the method are explained in more detail below using preferred embodiments with reference to the accompanying figures.
[0071] Fig. 1 shows a schematic front view of an embodiment of an eccentric screw pump! Fig. 2 shows a schematic side view of the eccentric screw pump according to Fig. 1;
[0072] Fig. 3 shows a schematic sectional view of the eccentric screw pump according to Fig. 1;
[0073] Fig. 4 shows a further schematic sectional view of the eccentric screw pump according to Fig. 1;
[0074] Fig. 5 shows a further schematic sectional view of the eccentric screw pump according to Fig. 1;
[0075] Fig. 6 shows a schematic detailed sectional view of the eccentric screw pump according to Fig. 1;
[0076] Fig. 7 shows a schematic view of an embodiment of a dosing system with an eccentric screw pump according to Fig. 1;
[0077] Fig. 8 shows a schematic detailed view of the dosing system according to Fig. 7;
[0078] Fig. 9 shows a schematic view of another embodiment of a
[0079] Dosing system with two eccentric screw pumps according to Fig. 1;
[0080] Fig. 10 shows a schematic perspective view of another embodiment of an eccentric screw pump;
[0081] Fig. 11 shows a schematic side view of the eccentric screw pump according to Fig. 10; and Fig. 12 shows a schematic block diagram of a method for operating an eccentric screw pump according to Fig. 1 or according to Fig. 10.
[0082] In the figures, identical or functionally equivalent elements have been given the same reference numerals unless otherwise stated.
[0083] Fig. 1 shows a schematic front view of an embodiment of an eccentric screw pump 1A. Fig. 2 shows a schematic side view of the eccentric screw pump 1A. Fig. 3 shows a schematic sectional view of the eccentric screw pump 1A. Fig. 4 shows a further schematic sectional view of the eccentric screw pump 1A. Fig. 5 shows a further schematic sectional view of the eccentric screw pump 1A. Fig. 6 shows a schematic detailed sectional view of the eccentric screw pump 1A. In the following, reference is made simultaneously to Figs. 1 to 6.
[0084] The eccentric screw pump 1A is suitable for metering a liquid medium M. The medium M to be metered can be, for example, an adhesive or sealant, water, an aqueous solution, a paint, a suspension, a viscous raw material, an emulsion, or a grease. The medium M can be liquid or pasty. For example, the medium M can contain fillers, for example so-called microballoons, fibrous, in particular short-fiber, components, or the like. The medium M can also be, for example, a cyanoacrylate. The medium M can also be an anaerobic adhesive. In particular, the medium M is a casting compound, particularly preferably an impregnating resin. The medium M can be one-component or two-component. The medium M is, in particular, low-viscosity and / or self-leveling.
[0085] The eccentric screw pump 1A comprises a drive 2. The drive 2 can have an electric motor. The drive 2 comprises a shaft coupling 3, which is coupled to a bearing shaft 5 by means of a coupling star 4. The coupling star 4 is made of a heat-insulating material, for example, a plastic material or rubber. The coupling star 4 is star-shaped and can, for example, have four arms. The coupling star 4 ensures thermal decoupling of the bearing shaft 5 from the shaft coupling 3 and vice versa.
[0086] The bearing shaft 5 is rotatably mounted on or in a bearing housing 7 by means of a bearing 6, for example in the form of a rolling bearing. A rotor unit 8 of the eccentric screw pump 1A is connected to the bearing shaft 5. The rotor unit 8 can also be referred to as a rotor train. The rotor unit 8 has a drive shaft 9, which is at least partially received in the bearing shaft 5 and is connected to the bearing shaft 5 in a rotationally fixed manner by means of a connecting element 10, for example in the form of a screw.
[0087] In addition to the drive shaft 9, the rotor unit 8 comprises a rotor 11, which is helical or spiral-shaped and thus has a helical or spiral-shaped outer contour. The rotor 11 can be made of a metallic material, for example, stainless steel, or a suitable plastic material.
[0088] A flexible shaft 12 is provided between the rotor 11 and the drive shaft 9, which connects the rotor 11 to the drive shaft 9 in a rotationally fixed manner. The flexible shaft 12 is placed between the drive shaft 9 and the flexible shaft 12, viewed along a longitudinal direction L of the rotor unit 8, which is oriented from the drive shaft 9 in the direction of the rotor 11 and parallel to a symmetry or central axis 13 of the rotor unit 8. The flexible shaft 12 can also be referred to as a flexible shaft. The flexible shaft 12 is preferably elastically deformable and enables an eccentric movement of the rotor 11. The flexible shaft 12 serves to transmit torque from the drive shaft 9 to the rotor 11. The flexible shaft 12 can be a wire rope, which is coated or sheathed, for example, with a plastic material or an elastomer.
[0089] The drive shaft 9 is accommodated, at least in sections, in a protective sleeve 14. The protective sleeve 14 is tubular or hollow-cylindrical and encloses the drive shaft 9 at least in sections. The protective sleeve 14 is made of a metallic material, for example, stainless steel. The protective sleeve 14 is pushed onto the drive shaft 9. The protective sleeve 14 is replaceable. Thus, the protective sleeve 14 can be replaced when it is worn. The protective sleeve 14 can therefore also be referred to as a wear protection sleeve. The protective sleeve 14 is designed to be rotationally symmetrical to the central axis 13.
[0090] The eccentric screw pump 1A further comprises a pump housing 15, through which the rotor unit 8 extends centrally. The pump housing 15 can be constructed rotationally symmetrically to the central axis 13. The pump housing 15 comprises a tubular or hollow-cylindrical tank section 16 for receiving the medium M. The tank section 16 is constructed rotationally symmetrically to the central axis 13. The tank section 16 can be tubular or hollow-cylindrical. The tank section 16 is hollow-body shaped. The tank section 16 can be cuboid-shaped, in particular cube-shaped. The tank section 16 can have any desired geometry.
[0091] Adjoining the tank section 16 is a funnel-shaped transition section 17. The transition section 17 is arranged between the tank section 16 and a flange section 18. The flange section 18 is tubular or hollow-cylindrical. The transition section 17 and the flange section 18 are part of the pump housing 15. An at least partially elastically deformable stator 19 is attached to the flange section 18. The stator 19 has a tubular stator outer part 20 and a stator inner part 21 received in the stator outer part 20. The stator outer part 20 is firmly connected to the flange section 18. The stator
[0092] 19 is detachably connected to the pump housing 15, in particular detachably to the flange section 18, by means of the stator outer part 20. The stator outer part
[0093] 20 can be screwed, clamped, or otherwise detachably connected to the flange section 18. The stator outer part 20 can also be part of the flange section 18. The stator outer part 20 can be made of a metallic material, for example, stainless steel.
[0094] The stator inner part 21 is mounted in the stator outer part 20 in a rotationally secure manner by means of anti-rotation devices 22, 23. The stator inner part 21 is made, in particular, of an elastomer. The stator inner part 21 has a helical or spiral inner geometry corresponding to the outer geometry of the rotor 11. For this purpose, a spiral or spiral opening is provided centrally in or on the stator inner part 21. The stator inner part 21 can protrude into the flange section 18, at least in sections. The stator outer part 20 and the stator inner part 21 are interchangeable.
[0095] The stator 19, in particular the stator outer part 20, has an outer diameter d. The outer diameter d is smaller than an inner diameter D of the tank section 16. Preferably, the inner diameter D is at least twice the outer diameter d. The inner diameter D can also be three times or more than three times the outer diameter d.
[0096] When the rotor 11 rotates in the stator 19 around the central axis 13, particularly in the stator inner part 21, the medium M is conveyed in the longitudinal direction L away from the drive shaft 9 according to the endless piston principle by the interaction of the rotor 11 with the stator inner part 21. The delivery volume per unit of time depends on the speed, size, pitch, and geometry of the rotor 11.
[0097] The at least partially elastically deformable stator 19, in particular the stator inner part 21, preferably has one more thread than the rotor 11 and twice the pitch length of the rotor 11. This leaves delivery chambers between the stator 19, in particular the stator inner part 21, and the rotor 11 rotating therein and additionally moving radially, which move continuously from an inlet side of the stator 19 to an outlet side thereof. Valves to limit the delivery chambers are not required. The size of the delivery chambers and thus the theoretical delivery rate depends on the pump size. A 360° rotation of the rotor unit 8 with free outlet results in the volumetric delivery rate per revolution. The delivery rate of the eccentric screw pump 1A can thus be varied via the speed of the rotor unit 8. The actual delivery rate depends on a resulting backpressure of the medium M.
[0098] The shape of the pumping chambers remains constant, so that the medium M is not compressed. With a suitable design, this type of progressive cavity pump 1A can therefore pump not only fluids, but also solids. The shear forces acting on the medium M are very small, so that, for example, plant, animal, and human cells can also be pumped non-destructively. A particular advantage of this type of progressive cavity pump 1A is that it pumps continuously and with little pulsation. This makes the progressive cavity pump 1A suitable for use in casting systems. Even highly viscous and abrasive media can be pumped without any problems.
[0099] With the help of the 1A eccentric screw pump, a wide variety of media M can be pumped gently and with low pulsation. The spectrum of media M ranges from water to media that are no longer self-flowing. Since the flow rate is proportional to the speed of the rotor 11, the 1A eccentric screw pump, in conjunction with appropriate measurement and control technology, is ideal for dosing tasks.
[0100] In the orientation of Figs. 1 to 6, the pump housing 15 is closed at the top by a seal housing 24. The seal housing 24 can be screwed to the pump housing 15. For this purpose, several fastening elements, in particular in the form of screws, can be provided. The seal housing 24 can be disc-shaped, at least in sections. The rotor unit 8, in particular the drive shaft 9, can be guided centrally through the seal housing 24.
[0101] The bearing housing 7 is mounted on the seal housing 24. The bearing housing 7 can be screwed to the seal housing 24. The drive 2 has a drive housing 27 through which the shaft coupling 3 passes. The drive housing 27 can be connected to the bearing housing 7 by means of a union nut 28.
[0102] The seal housing 24 comprises a receiving section 29, which is constructed rotationally symmetrically to the central axis 13. A sealing device 30 is received in the receiving section 29. The sealing device 30 provides a radial seal with respect to the rotor unit 8, in particular with respect to the protective sleeve 14 of the rotor unit 8. The sealing device 30 comprises a sealing element 31 received in the receiving section 29 and an O-ring 33 received in a groove 32 in the sealing element 31. The O-ring 33 provides a radial seal with respect to the receiving section 29. Facing away from the groove 32, the sealing element 31 comprises a plurality of sealing lips 34, 35, which seal with respect to the protective sleeve 14. Two sealing lips 34, 35 can be provided. The sealing device 30 is arranged such that it is placed above the tank section 16 with respect to a direction of gravity g. The longitudinal direction L can be oriented along the direction of gravity g.The central axis 13 can run parallel to or along the direction of gravity g.
[0103] An inlet 36 is attached to the seal housing 24 and projects into an interior space 37 of the tank section 16, which is enclosed by the tank section 16. The inlet 36 enables the pump housing 15 to be filled below the level of the medium M. This means that the medium filled into the tank section 16 is supplied to the interior space 37 below a fill level F of the medium M in the tank section 16. This reliably prevents the formation of bubbles in the medium M when it is filled into the tank section 16. The sealing device 30 is always arranged above the fill level F so that it does not come into contact with the medium M.
[0104] Furthermore, a fill level sensor 38 is attached to the seal housing 24, which also extends into the interior space 37. The fill level sensor 38 enables an analog fill level measurement from 0 to 100% of the medium M. With the help of the fill level sensor 38, a permanent monitoring of the fill level F of the medium M in the pump housing 15, in particular in the tank section 16, can be carried out.
[0105] Furthermore, several valves 39A, 39B are attached to the seal housing 24, which make it possible to discharge exhaust air from the pump housing 15, to supply air to it, or to create a vacuum in the interior 37. Furthermore, an overfill sensor 40 is attached to the seal housing 24, which provides protection against overfilling of the pump housing 15 with the medium M. A temperature sensor 41 is attached to the seal housing 24 in the area of the receptacle from section 29. With the help of the temperature sensor 41, a temperature of the sealing device 30 can be detected and / or monitored. This enables timely replacement of the sealing device 30 if it should become thermally damaged. With the help of the temperature sensor 41, a temperature of the bearing 6 can also be detected and / or monitored.
[0106] An end piece unit 42 is attached to the front of the stator 19. The end piece unit 42 can be a hose connection or comprise a hose connection. The end piece unit 42 is fastened to the stator 19, in particular to the stator outer part 20, by means of a union nut 43. The end piece unit 42 comprises an end piece 44, which is fastened to the stator 19, in particular to the stator outer part 20, by means of the union nut 43, and a hose connection element 45, which can be screwed into the end piece 44. A combined temperature-pressure sensor 46 is attached to the end piece unit 42, in particular to the end piece 44.
[0107] Fig. 7 shows a schematic view of an embodiment of a dosing system 47.
[0108] The dosing system 47 comprises a medium supply 48. The medium supply 48 can be a tank in which the medium M is held. Furthermore, the dosing system 47 comprises a ring line 49 which is in fluid communication with the medium supply 48. The medium M circulates in the ring line 49, as shown by arrows 50. A pump can be provided for this purpose. The medium M can circulate in the ring line 49, for example, at a pressure of 3 bar. The medium supply 48 can comprise a heater and / or temperature control. A temperature sensor, which is connected, for example, to the ring line 49, can be provided. A control loop can be implemented with the aid of the temperature sensor and the heater and / or temperature control. Furthermore, the dosing system 47 comprises a plurality of eccentric screw pumps 1A as previously mentioned. Each eccentric screw pump 1A is assigned an inlet line 51, 52, 53, 54, 55, which branches off from the ring line 49.The inlet lines 51, 52, 53, 54, 55 are connected to the respective inlets 36 of the eccentric screw pumps 1A. Each inlet line 51, 52, 53, 54, 55 is assigned a valve 56, 57, 58, 59, 60, which is configured to open or close the respective inlet line 51, 52, 53, 54, 55. The valves 56, 57, 58, 59, 60 are each designed to enable a rubber-to-rubber seal. A rubber-to-metal or rubber-to-polytetrafluoroethylene (PTFE) seal is also possible. The valves 56, 57, 58, 59, 60 can be diaphragm valves. However, valves 56, 57, 58, 59, 60 can also be any other valves.
[0109] Temperature and pressure monitoring can be performed using the temperature sensor 41 and the temperature-pressure sensor 46. Each eccentric screw pump 1A can be assigned a thermal insulation and / or heating sleeve 61, which encloses at least some sections of the pump housing 15 and the stator 19. The thermal insulation and / or heating sleeve 61 can be made, for example, of a porous plastic material. The thermal insulation and / or heating sleeve 61 is optional.
[0110] Fig. 8 shows a schematic detailed view of the dosing system 47.
[0111] As shown in Fig. 8, a hose connection 62 can be attached to the end piece unit 42, which is attached to the front of the stator 19. The hose connection 62 leads to a dosing point. A dosing needle 63 is attached to the end of the hose line.
[0112] Fig. 9 shows a schematic view of another embodiment of a dosing system 64. The dosing system 64 comprises two eccentric screw pumps 1A, wherein one eccentric screw pump 1A is supplied with a first medium M1 via an inlet line 65, and the other of the two eccentric screw pumps 1A is supplied with a second medium M2 via an inlet line 66. Each inlet line 65, 66 can be assigned a ring line 49 with a medium supply 48, as mentioned above. The dosing system 64 is suitable for two-component applications (2K applications).
[0113] The inlet lines 65, 66 are fluidically connected to the inlets 36 of the eccentric screw pumps 1A. Each inlet line 65, 66 is assigned a valve 67, 68. The valves 67, 68 can be diaphragm valves. Hose connections 69, 70 are connected to the end piece units 42 of the eccentric screw pumps 1A, which lead to a mixing block 71. In the mixing block 71, the media M1, M2 can be combined and mixed. Furthermore, a static mixer 72 can be connected downstream of the mixing block 71, which mixes the media M1, M2 with each other. A metering needle 73 for metering the mixed media M1, M2 can be attached to the static mixer 72. For example, a mixing ratio of the media M1, M2 of 14, F2, 1 ; 3, 1, 1:5, or 140. Any desired mixing ratio can be set. A very precise mixing ratio is possible.
[0114] Fig. 10 shows a schematic perspective view of another embodiment of an eccentric screw pump 1B. Fig. 11 shows a schematic side view of the eccentric screw pump 1B. Reference is made to Figs. 10 and 11 simultaneously below.
[0115] The eccentric screw pump 1B differs from the eccentric screw pump 1A only in that the eccentric screw pump 1B has several rotor units 8, several stators 19, several drives 2, several drive housings 27, and the like, all of which are assigned to and mounted on a common pump housing 15. The main advantage of this arrangement is that several metering points can be operated with one pump housing 15. Only one inlet line 51 from the ring line 49 and one valve 56 in the inlet line 51 are then required.
[0116] Particularly preferably, the eccentric screw pump 1B has at least two stators 19, at least two rotor units 8, and at least two sealing devices 30 for sealing the at least two rotor units 8 relative to the tank section 16 of the pump housing 15. However, the number of stators 19, rotor units 8, and sealing devices 30 is not limited to two. For example, four stators 19, four rotor units 8, and four sealing devices 30 can be provided. The at least two sealing devices 30 are arranged outside the tank section 16.
[0117] During operation of the eccentric screw pump 1B for metering the medium M, M1, M2, each of the at least two rotor units 8 cooperates with one of the at least two stators 19, wherein the at least two stators 19 are attached to the pump housing 15, and wherein the at least two rotor units 8 extend at least partially through the pump housing 15.
[0118] Optionally, the pump housing 15 can have a plurality of detachably connected pump housing modules 74, 75, 76, 77. The pump housing modules 74, 75, 76, 77 can, for example, be latched and / or screwed together. The number of pump housing modules 74, 75, 76, 77 is arbitrary. For example, four pump housing modules 74, 75, 76, 77 are provided. Individual ones of the pump housing modules 74, 75, 76, 77 can carry the inlet 36, the fill level sensor 38, the valves 39A, 39B and / or the overfill sensor 40. Fig. 12 shows a schematic block diagram of a method for freeing the eccentric screw pump 1A, 1B.
[0119] In the method, in a step S1, the respective medium M, Ml, M2 is metered using the eccentric screw pump 1A, 1B. In a step S2, a preferably constant fill level F of the medium M, Ml, M2 is maintained in the tank section 16 by supplying the medium M, Ml, M2 to the tank section 16 during step S1. The fill level F thus remains constant. However, this is not absolutely necessary. A volume of the inflowing medium M, Ml, M2 can always be greater than a metered volume of the medium M, Ml, M2. During step S1, a temperature measurement and a pressure measurement of the medium M, Ml, M2 can be carried out. For this purpose, the combined temperature-pressure sensor 46 is used, for example.
[0120] Although the present invention has been described using exemplary embodiments, it can be modified in many ways.
[0121] LIST OF REFERENCE SYMBOLS
[0122] 1A eccentric screw pump
[0123] IB eccentric screw pump
[0124] 2 drive
[0125] 3 Shaft coupling
[0126] 4 coupling star
[0127] 5 bearing shaft
[0128] 6 warehouses
[0129] 7 bearing housing
[0130] 8 Rotor unit
[0131] 9 Drive shaft
[0132] 10 Connecting element
[0133] 11 Rotor
[0134] 12 Flex shaft
[0135] 13 Central axis
[0136] 14 Protective sleeve
[0137] 15 Pump housing
[0138] 16 Tank section
[0139] 17 Transition section
[0140] 18 Flange section
[0141] 19 Stator
[0142] 20 Stator outer part
[0143] 21 Stator inner part
[0144] 22 Anti-twist device
[0145] 23 Anti-twist device
[0146] 24 Seal housing
[0147] 27 Drive housing
[0148] 28 union nut
[0149] 29 Receiving section 30 Sealing device
[0150] 31 Sealing element
[0151] 32 grooves
[0152] 33 O-ring
[0153] 34 Sealing lip
[0154] 35 Sealing lip
[0155] 36 Inlet
[0156] 37 Interior
[0157] 38 Level sensor
[0158] 39A Valve
[0159] 39B Valve
[0160] 40 Overfill sensor
[0161] 41 Temperature sensor
[0162] 42 End piece unit
[0163] 43 union nut
[0164] 44 End piece
[0165] 45 Hose connection element
[0166] 46 Temperature-pressure sensor
[0167] 47 Dosing system
[0168] 48 Medium supply
[0169] 49 ring line
[0170] 50 arrows
[0171] 51 Inlet line
[0172] 52 Inlet line
[0173] 53 Inlet line
[0174] 54 Inlet line
[0175] 55 Inlet line
[0176] 56 Valve
[0177] 57 Valve
[0178] 58 Valve 59 Valve
[0179] 60 valve
[0180] 61 Thermal insulation and / or heating sleeve
[0181] 62 hose connection
[0182] 63 Dosing needle
[0183] 64 Dosing system
[0184] 65 Inlet line
[0185] 66 Inlet line
[0186] 67 Valve
[0187] 68 Valve
[0188] 69 Hose connection
[0189] 70 hose connection
[0190] 71 mixing block
[0191] 72 mixers
[0192] 73 Dosing needle
[0193] 74 Pump housing module
[0194] 75 Pump housing module
[0195] 76 Pump housing module
[0196] 77 Pump housing module d outer diameter
[0197] D inner diameter
[0198] F Level g Direction of gravity
[0199] L longitudinal direction
[0200] M Medium
[0201] ml Medium
[0202] M2 Medium
[0203] SI step
[0204] S2 step
Claims
PATENT CLAIMS 1. Eccentric screw pump (1B) for metering a medium (M, M1, M2), comprising at least two stators (19), at least two rotor units (8), wherein during operation of the eccentric screw pump (1B) for metering the medium (M, M1, M2), each of the at least two rotor units (8) interacts with one of the at least two stators (19), a pump housing (15) to which the at least two stators (19) are attached and through which the at least two rotor units (8) extend at least in sections, wherein the pump housing (15) has a tank section (16) for receiving the medium (M, M1, M2), and at least two sealing devices (30) for sealing the at least two rotor units (8) with respect to the tank section (16), wherein the at least two sealing devices (30) are arranged outside the tank section (16).
2. Eccentric screw pump according to claim 1, comprising a fill level sensor (38) which is designed to continuously detect a fill level (F) of the medium (M, M1, M2) within the tank section (16).
3. Eccentric screw pump according to claim 1 or 2, wherein the tank section (16) is formed by a cross-sectional enlargement of the pump housing (15), and / or wherein an inner diameter (D) of the tank section (16) is larger than a respective outer diameter (d) of the at least two stators (19), and wherein the inner diameter (D) is in particular at least twice as large as the outer diameter (d).
4. Eccentric screw pump according to one of claims 1 - 3, wherein the pump housing (15) has a flange section (18) and a transition section (17) connecting the tank section (16) and the flange section (18), wherein the transition section (17) is funnel-shaped, and wherein the at least two stators (19) are each attached in particular to the flange section (18).
5. Eccentric screw pump according to one of claims 1 - 4, wherein the eccentric screw pump (1B) has an inlet (36) projecting into the tank section (16) for filling the medium (M, M1, M2) below the surface.
6. Eccentric screw pump according to one of claims 1 - 5, comprising a seal housing (24) connected to the pump housing (15), wherein each of the at least two sealing devices (30) is accommodated in the seal housing (24), and / or wherein the at least two sealing devices (30) each have at least one sealing lip (34, 35), wherein the at least two rotor units (8) each have a protective sleeve (14), and wherein the at least one sealing lip (34, 35) rests against the protective sleeve (14).
7. Eccentric screw pump according to one of claims 1 - 6, comprising a drive (2) for driving each of the at least two rotor units (8), wherein the drive (2) is coupled to one of the at least two rotor units (8) by means of a coupling star (4), and wherein the coupling star (4) is made of a heat-insulating material.
8. Eccentric screw pump according to one of claims 1 - 7, comprising a temperature sensor (41) for monitoring the temperature of each of the at least two sealing devices (30).
9. Eccentric screw pump according to one of claims 1 - 8, comprising a thermal insulation and / or heating sleeve (61) which encloses the pump housing (15) at least in sections.
10. Eccentric screw pump according to one of claims 1 - 9, comprising an overfill sensor (40) for monitoring a maximum fill level (F) of the medium (M, M1, M2) in the tank section (16).
11. Eccentric screw pump according to one of claims 1 - 10, comprising a valve (39A, 39B) for venting or venting the tank section (16), for applying a vacuum to the tank section (16) and / or for pressurizing the tank section (16) with a process gas, such as nitrogen, argon or the like.
12. Eccentric screw pump according to one of claims 1 - 11, comprising an end piece unit (42) with a temperature-pressure sensor (46) attached to each of the at least two stators (19).
13. Eccentric screw pump according to one of claims 1 - 12, wherein the pump housing (15) has a plurality of pump housing modules (74, 75, 76, 77) detachably connected to one another.
14. Dosing system (47) for dosing a medium (M, M1, M2), comprising at least two eccentric screw pumps (1B) according to one of the claims 1 - 13, a ring line (49) to which the at least two eccentric screw pumps (1B) are connected and through which the medium (M, Ml, M2) flows continuously, and a medium supply (48) for supplying the ring line (49) with the medium (M, Ml, M2).
15. Method for operating an eccentric screw pump (1B) according to one of claims 1 - 13, with the following steps: a) dosing (S1) of the medium (M, M1, M2) with the aid of the eccentric screw pump (1B), and b) maintaining (S2) a fill level (F) of the medium (M, M1, M2) in the tank section (16) by supplying the medium (M, M1, M2) to the tank section (16) during step a).