Stator of eccentric screw pump, eccentric screw pump and manufacturing method thereof

Abstract

The invention relates to a stator (3; 3 ') for an eccentric screw pump (1). 103), comprising a sheath (19; 119) and an elastic inner liner (21; 121) and a stator body (15; 115), an inner liner (21; 121) is provided on the sheath. According to a first aspect, the sheath and the liner are each made of a thermoplastic material. According to a second aspect, the sheath is composed of a thermoplastic material, the liner is composed of a material having elastomeric properties, and the stator body is made using a two-component injection molding process or an at least two-stage casting process. According to a third aspect, the sheath at least partially has a threaded-surface-like outer surface (31; 131), which is at least in some regions by means of an additional release surface (36; 136) in the housing. Furthermore, according to a fourth aspect, a stator (3; 103) for an eccentric screw pump (1), having an inner component or lining (21; 21 ') for interacting with a rotor (4) of the eccentric screw pump (1); 121), which is made of a thermoplastic elastomer or a thermoplastic polyurethane. The invention further relates to an eccentric screw pump and to a method for producing a stator of an eccentric screw pump.

Description

Technical Field

[0001] The present invention relates to a stator of an eccentric screw pump, an eccentric screw pump having such a stator, and a method for manufacturing the stator of an eccentric screw pump. Existing technology

[0002] Eccentric screw pumps are known in their own right. Such pumps have a stator and a rotor that rotates eccentrically within channels in the stator. Both the stator and rotor channels are provided with threaded surfaces that interact during operation to form a delivery chamber for the medium to be conveyed.

[0003] A series of stator structures for eccentric screw pumps have been proposed.

[0004] For example, in a conventional structure, the spirally wound inner surface of the stator is formed within an elastomer, thus exhibiting elastic flexibility. This allows for the formation of a dicchtline around each conveying cavity through appropriate design of the stator and rotor geometry. This enables pressure to be maintained during the conveying of the medium. Furthermore, in this structure, the elasticity of the stator's inner surface contributes to improved wear resistance and service life of the stator, especially when conveying abrasive media such as sand or similar materials.

[0005] In the aforementioned conventional structure, a steel pipe is first manufactured and machined separately to create the stator. An elastomer is then injected into the steel pipe to form the elastomer body, which is then connected to the steel pipe. This process specifically includes degreasing and sandblasting the steel pipe before injecting the elastomer, and applying an adhesive coating consisting of two single layers as a pretreatment. The coating, composed of a primer layer and an adhesive layer, is used to form a reliable, strong, and permanent bond between the steel and the elastomer.

[0006] In addition, a stator is proposed in which a retaining sleeve is subsequently detachably arranged around the elastomer body during stator assembly, without permanently bonding the elastomer body and the retaining sleeve together.

[0007] In addition, traditional stator structures use a fixed metal sheath, such as steel, cast aluminum or cast steel, which gives the internal elastic material housed in the sheath a uniform wall thickness.

[0008] In addition, stators made entirely of elastomeric stators or stators made entirely of non-elastic flexible plastics (such as PA (polyamide) or PTFE (polytetrafluoroethylene)) (i.e., so-called solid stators) have been proposed. Therefore, such stators have rigid, non-flexible inner surfaces.

[0009] Therefore, the current conventional methods for manufacturing stators for eccentric screw pumps—which have support sleeves and are able to maintain pressure or overcome back pressure by forming sealing lines—are relatively complex and costly.

[0010] For example, the manufacturing process of the elastomer body for vulcanized installation is complex, energy-intensive, and costly. Similarly, the manufacturing and machining of the metal sheath are energy-intensive and costly.

[0011] In addition, attaching the elastomer to the metal surface of the sheath requires multiple and time-consuming pretreatment steps to achieve good adhesion between the two.

[0012] Furthermore, as a component of the eccentric screw pump, the stator typically wears down during operation. Therefore, frequent stator replacements may be necessary. The presence of the elastomer body, especially its fixed connection to the metal sheath made of steel tubing, makes the recovery of the worn stator difficult. Even recovering the elastomer itself is challenging.

[0013] Against this backdrop, there is a need to provide an improved stator structure for an eccentric screw pump that is simpler and more economical to manufacture, and preferably more sustainable in terms of manufacturing process. Invention Overview

[0014] Against this background, the object of the present invention is to provide a stator for an eccentric screw pump that avoids or mitigates at least one, some, or all of the aforementioned disadvantages. Furthermore, the present invention also provides a correspondingly improved eccentric screw pump and a correspondingly improved method for manufacturing the stator of the eccentric screw pump.

[0015] According to the invention, this objective is achieved by a stator for an eccentric screw pump having the features of claim 1 and / or a stator for an eccentric screw pump having the features of claim 3 and / or a stator for an eccentric screw pump having the features of claim 9 and / or an eccentric screw pump having the features of claim 19 and / or a method having the features of claim 20.

[0016] Therefore, a first aspect of the present invention provides a stator for an eccentric screw pump, the stator comprising a stator body having a supporting sheath and an elastic liner disposed on the sheath. Here, both the sheath and the liner are made of thermoplastic material.

[0017] According to a second aspect of the invention, a stator for an eccentric screw pump is provided, the stator comprising a stator body having a support sheath and an elastic liner disposed on the sheath, wherein the sheath is made of a thermoplastic material, the liner is made of a material having elastomeric properties, and the stator body is manufactured by a two-component injection molding process or at least a two-stage casting process.

[0018] Furthermore, according to a third aspect of the invention, a stator for an eccentric screw pump is provided, the stator comprising a stator body having a sheath and an elastic liner disposed inside the sheath, wherein the sheath has at least partially a threaded surface on its outer side. The outer surface, such as a dual-channel threaded surface, is modified at least in certain areas by an additional release surface.

[0019] According to a fourth aspect of the invention, the above-mentioned object of the invention is further achieved by a stator for an eccentric screw pump, the stator including internal components or liners provided for interaction with the rotor of the eccentric screw pump, which are made of thermoplastic elastomer or thermoplastic polyurethane.

[0020] Furthermore, the eccentric screw pump includes a rotor and a stator designed according to the present invention. The stator is designed to interact with the rotor and to at least partially house the rotor.

[0021] The present invention also provides a method for manufacturing a stator for an eccentric screw pump, particularly for manufacturing a stator designed according to the invention. In the method according to the invention, the stator body is constructed from a sheath made of thermoplastic material, and the sheath is provided with an inner liner made of a material having elastomeric properties. Here, the stator body is manufactured using a two-component injection molding process or at least a two-stage casting process.

[0022] The basic concept of this invention is that by using thermoplastic materials to construct the elastic inner liner and the sheath respectively, the cost, production time and energy consumption required for manufacturing the stator can be significantly reduced.

[0023] When using thermoplastic materials to construct elastic liners or internal components, significant energy savings can be achieved compared to producing and vulcanizing elastomers. Using thermoplastic materials instead of metals to produce the sheath can also significantly reduce costs and energy consumption. Therefore, this invention can significantly reduce the carbon footprint (PCF) and produce stators in a more sustainable and resource-efficient manner. Furthermore, using thermoplastic materials for both the sheath and liner allows for a strong and reliable bond between these components at low cost.

[0024] For example, according to one concept of the invention, when using thermoplastic materials (especially materials of the same type or material family), such as materials used for the sheath and liner, if one or more mechanical properties are adjusted to be different, the entire stator body with the fixed connection of the sheath and liner can be recycled as a single material component. For example, the used stator body (preferably after cleaning) can be shredded and crushed into granules suitable for further processing. These granules can then be processed like fresh plastic granules, for example, on a conventional injection molding machine, or sold, for example, to a material compounder. In this way, the invention produces a stator for an eccentric screw pump with a resilient liner and good performance, and the stator also has improved recyclability.

[0025] Advantageously, the proposed sheath, constructed from thermoplastic materials, allows for relatively free geometric design. For example, the sheath can conform to the internal geometry of the stator (e.g., in a rolled form), thereby optimizing the wall thickness of the liner to further improve manufacturability, such as making the wall thickness design more uniform. Furthermore, in this way, particularly when used in conjunction with thermoplastic liners (e.g., made of thermoplastic elastomers or thermoplastic polyurethanes), the component weight of the finished stator can be reduced. This helps reduce resource consumption during stator manufacturing and CO2 emissions during transportation, and facilitates easier handling of the stator during manufacturing and customer use.

[0026] Manufacturing the stator body using a two-component injection molding process or at least a two-stage casting process, particularly by injection molding separately using the sheath and / or liner, allows for a good connection between the sheath and liner at low cost. This also contributes to the economic efficiency and sustainable production of the stator. Furthermore, this injection molding or casting process, especially by injection molding separately using the sheath, allows for a wide range of simple modifications to the sheath geometry, particularly by adapting the sheath geometry to the internal geometry of the stator with little or no additional cost, while also retaining the aforementioned advantages of good manufacturability and low component weight.

[0027] The release surface provided according to one aspect of the invention further simplifies the manufacturing of the stator body and contributes to more economical and efficient manufacturing. In particular, the release surface enables the stator body to be manufactured in a simple casting mold (especially a slide-less double-plate mold). Preferably, the release surface is arranged to avoid undercutting, which would hinder easy separation of the mold plates at the parting line (Trennebene) without a separate movable mold element.

[0028] According to another aspect of the invention, using thermoplastic elastomers or thermoplastic polyurethanes as thermoplastic plastic materials to construct internal components or liners contributes to the economical and sustainable production of stators, particularly reducing the carbon dioxide footprint, whether used alone or in combination with a sheath made of thermoplastic materials. The combination of thermoplastic elastomers or thermoplastic polyurethanes with a thermoplastic sheath improves the recyclability of the stator.

[0029] For example, compared to conventional methods that use an elastomer body fixedly connected to a steel sheath, the present invention can reduce costs by up to about 70% and reduce the carbon dioxide footprint or PCF by up to about 70% to 80%.

[0030] Advantageous designs and improvements of the present invention are embodied in the dependent claims and in the description with reference to the accompanying drawings.

[0031] In particular, the stator body is manufactured using a two-component injection molding process. This enables a reliable connection between the sheath and the liner at low cost, achieving economical and sustainable production, and allowing for complex geometries of the sheath at low additional cost. These complex geometries, in turn, improve manufacturability and reduce the weight of the stator, for example, by making the sheath substantially conform to the geometry of the liner or internal components.

[0032] In one improved design, the sheath and liner are directly connected. This simplifies the structure and manufacturing of the stator body. There is no need for complex intermediate layers to enhance the adhesion between the sheath and liner. Specifically, this direct connection can be achieved using a two-component injection molding process or at least a two-stage casting process, where the sheath and liner are injection molded at different stages of the process.

[0033] According to one design scheme, the liner's wall thickness is substantially uniform. This is beneficial for improving the manufacturing of the liner in injection molding / casting processes, especially for thermoplastic materials such as thermoplastic elastomers (TPE) or thermoplastic polyurethanes (TPU). Uniform and as constant a wall thickness as possible is advantageous, particularly when processing TPE or TPU, as this avoids undesirable material buildup, shrinkage cavities, and warpage. Furthermore, the uniform wall thickness avoids excessively long cooling times during the liner injection molding process, thus enabling an economical manufacturing process.

[0034] In one improved embodiment, the sheath is connected to the inner liner on the inner side via a connecting surface that is at least partially designed as a threaded surface (especially a double-channel threaded surface). This forms a stator body in which the sheath and inner liner can be treated as a single unit, and the inner liner is reliably mechanically supported by the sheath on the outer side, exhibiting pressure stability.

[0035] Specifically, the sheath has at least a partially threaded outer surface on its outer side, particularly a double-channel threaded outer surface. This type of sheath curling and outer surface allows for a substantially uniform wall thickness in the liner / internal components, which is beneficial for manufacturing processes, while also ensuring at least a substantially uniform wall thickness for the sheath itself. This relatively complex molding of the sheath can be achieved relatively simply and economically using thermoplastic materials, thus facilitating the manufacture of liners with uniform wall thickness using TPE or TPU.

[0036] In one embodiment of the invention, the sheath can be reinforced on the outer side by reinforcing ribs, which are preferably integrally formed with the sheath. This further enhances the mechanical support function of the sheath. For example, the reinforcing ribs can extend along the stator body.

[0037] In one design, the outer contour of the sheath can be designed to allow the stator body to be manufactured in a slide-less double-plate mold. In this design, manufacturability in a slide-less double-plate mold is achieved, in particular, by providing a certain number, shape, and size of demolding surfaces on the outer side of the sheath.

[0038] In particular, the threaded outer surface can be modified, at least in certain areas, by using additional release surfaces. These release surfaces facilitate economical and cost-effective manufacturing of the stator body and help avoid the use of complex molds (e.g., for injection molding). For example, the release surfaces can be arranged to allow the stator body to be manufactured in a slide-less two-plate mold without undercutting during demolding.

[0039] According to one design, each release surface is designed to be substantially flat, or at least partially substantially flat. This simplifies the design of the release surfaces and makes them advantageous for other applications, particularly for engaging machine tools or engaging transport or holding devices. However, unlike the flat design of the release surfaces, they can also be designed not to be flat, as long as the shape of the release surfaces prevents undercutting in the viewing direction toward the parting surface of the forming tool. For example, in another design, each release surface is designed to be curved, and here specifically formed by mutually parallel generation lines.

[0040] According to a further improvement, the wall thickness of the sheath is reduced in the demolding surface region compared to other areas of the sheath's threaded outer surface. Since this reduction in sheath wall thickness is confined to the demolding surface region, excessive unevenness in sheath wall thickness can be prevented. Simultaneously, the resource input required for sheath manufacturing can be limited, resulting in a lighter and easier-to-manufacture stator.

[0041] In another design, the demolding surfaces are arranged on both sides of the outer central plane of the sleeve, relative to the central plane of the stator (in which the stator's longitudinal axis lies). Here, the central plane may specifically correspond to the parting surface of a molding tool (e.g., an injection mold). In particular, in an improved embodiment, the demolding surfaces may be arranged near the central plane. In a further improved embodiment, the sleeve may be provided with reinforcing ribs on the outer side, and the demolding surfaces may be arranged near at least one of these reinforcing ribs.

[0042] In one improved embodiment, two or more demolding surfaces are respectively located on the outer side of the sheath on two opposite longitudinal sides of the stator.

[0043] According to another design scheme, the release surface is designed and arranged such that the release surface, or at least part of the release surface, can:

[0044] - Used in the stator manufacturing process to handle the stator or sheath, or both; or

[0045] - Used for handling the stator when assembling the stator onto the rotor of an eccentric screw pump; or

[0046] - A combination used for this type of processing.

[0047] Therefore, the release surface can be equipped with additional functions and serve as an assembly aid when installing the stator into the pump, and / or as a processing aid during manufacturing. In this case, the release surface is particularly suitable as or configured as a mating surface for processing tools or processing devices or assembly tools. During manufacturing, processing can be particularly automated, for example, by a robot. Additionally or alternatively, the release surface can also serve as an aid during manual assembly (whether or not tools are used) or manual processing (whether or not processing devices are used).

[0048] Specifically, the liner is made of thermoplastic elastomer or thermoplastic polyurethane. This choice of material for the liner makes stator production more economical and sustainable, particularly by reducing the "product carbon footprint." Thermoplastic elastomer or thermoplastic polyurethane can be combined with the thermoplastic sheath, which also improves the recyclability of the stator.

[0049] In one design, the sheath is made of polyamide, polypropylene, or thermoplastic polyurethane.

[0050] According to the further improvement plan:

[0051] - The inner lining is made of thermoplastic elastomer, and the outer sheath is made of polypropylene; or

[0052] - The inner lining is made of thermoplastic elastomer, and the outer sheath is made of polyamide; or

[0053] - The inner lining is made of thermoplastic polyurethane, and the outer sheath is made of polyamide; or

[0054] The inner liner is made of soft thermoplastic polyurethane, and the outer sheath is made of rigid thermoplastic polyurethane. Therefore, a variety of exemplary material combinations can be used to manufacture economical and sustainable eccentric screw pump stators suitable for a wide range of applications, depending on the medium being pumped and / or the stator's resistance to contact with that medium. Furthermore, the aforementioned material combinations for the sheath and liner significantly improve recyclability.

[0055] In an alternative design of the invention, the liner may be made of a polymeric elastomer, and in particular, the sheath may be made of polyamide. For example, by using injection molding processes, such as two-component or two-stage injection molding, the liner, as an elastomer component, can be directly attached to the sheath, forming a direct connection without the need for one or more adhesive layers inserted in between. This, in turn, simplifies the manufacturing process, avoiding multiple processing steps and complex preparation work for the sheath to ensure good adhesion. Furthermore, it advantageously saves on coating agents used for adhesion. Thus, a stator body with a plastic-rubber direct composite material can be manufactured. This stator body can be produced independently of the sheath geometry; for example, a cylindrical sheath can also be used. This plastic-rubber direct composite material can be achieved, in particular, by appropriately combining a thermoplastic material for the sheath with an elastomer for the liner, wherein polyamide is a particularly preferred material for the sheath. This design, in turn, enables the stator to be produced in a more economical and sustainable manner.

[0056] In one design of the fourth aspect, the stator may further include a support sleeve, wherein the sleeve is manufactured as a separate component and the internal components are housed within the sleeve, or the sleeve is connected to an inner liner to form the stator body. Preferably, the sleeve is made of a thermoplastic material, particularly polyamide, polypropylene, or thermoplastic polyurethane.

[0057] In the fourth aspect of the design scheme, it can be specified that:

[0058] - The lining or internal components are made of thermoplastic elastomer, while the sheath is made of polypropylene; or

[0059] - The liner or internal components are made of thermoplastic elastomer, and the sheath is made of polyamide; or

[0060] - The liner or internal components are made of thermoplastic polyurethane, and the sheath is made of polyamide; or

[0061] - The liner or internal components are made of soft thermoplastic polyurethane, and the sheath is made of rigid thermoplastic polyurethane.

[0062] In an improvement of the fourth aspect of the invention, the sheath may have at least partially a threaded outer surface on the outside, and the threaded outer surface may be modified at least in certain areas by an additional release surface.

[0063] The stator proposed according to the invention can be used, for example, as a stator for building materials, and is also possible and useful for various other applications, such as conveying various media and various eccentric screw pumps and applications. Brief description of the attached figures

[0064] The present invention will be described in more detail with reference to the exemplary design shown in the accompanying drawings.

[0065] The accompanying drawings are intended to further illustrate the invention and form part of this specification. The drawings demonstrate various design embodiments of the invention and, together with the description, serve to explain the principles of the invention. Other design embodiments of the invention and its many anticipated advantages will be more readily understood by referring to the following detailed description. Elements in the drawings are not necessarily drawn to the same scale. The same reference numerals denote corresponding similar parts.

[0066] Figure 1 A schematic simplified side view of an eccentric screw pump according to one embodiment is shown;

[0067] Figure 2 An illustration according to this embodiment is shown. Figure 1 Side view of the stator of the eccentric screw pump shown;

[0068] Figure 3 It shows Figure 2 The stator in Figure 2 The view in cross section AA shown;

[0069] Figure 4 It shows Figure 2 The stator in Figure 2 The view in the longitudinal section BB shown;

[0070] Figure 5 It shows Figure 2 The stator in Figure 4 Another view in cross-section CC shown;

[0071] Figure 6 It shows that according to Figure 2 A first perspective view of the stator in an embodiment;

[0072] Figure 7 It shows Figure 6 Details of part D in the 3D model;

[0073] Figure 8 It shows the relationship with Figure 2Another perspective view of the stator consistent with the embodiment;

[0074] Figure 9 An illustration of another embodiment with Figure 1 A side view of a similar eccentric screw pump stator;

[0075] Figure 10 It shows Figure 9 The stator in Figure 9 The view in the longitudinal section FF shown;

[0076] Figure 11 It shows Figure 9 The stator in Figure 9 The view in the cross section EE shown;

[0077] Figure 12 It shows Figure 9 The stator in Figure 10 Another view in cross-section GG shown;

[0078] Figure 13 It shows Figure 9 First three-dimensional view of the stator; and

[0079] Figure 14 It shows Figure 9 Another three-dimensional view of the stator.

[0080] Unless otherwise stated, the same reference numerals in the figures denote the same or similarly functional components. All directional indications, such as “top,” “bottom,” “left,” “right,” “above,” “below,” “horizontal,” “vertical,” “rear,” “front,” and similar terms, are for illustrative purposes only and are not intended to limit the implementation to the specific arrangement shown in the figures. Invention Details

[0081] Figure 1 A simplified schematic side view of an eccentric screw pump 1 is shown. The eccentric screw pump 1 has a stator 3, which, in the illustrated embodiment, is coupled to a housing 6 on the supply side. As schematically shown by arrow 64, the housing 6 delivers the medium to the inlet side of the stator 3. On the outlet side, the medium to be delivered flows along… Figure 1 The material is conveyed out in the direction indicated by the middle arrow 66. However, it should be understood that... Figure 1 The eccentric screw pump 1 shown is merely an example, and the stator 3 and its variations, which will be described in more detail below, can be similarly used for other types of eccentric screw pumps 1.

[0082] The stator 3 is an elongated component with a longitudinal direction L. The stator 3 has a channel 13 along direction L, which has a threaded inner surface. Figure 1Not shown in detail. A rotor 4, having a threaded, planar outer surface, is arranged in channel 13. During operation of the eccentric screw pump 1, the rotor 4 can rotate eccentrically within channel 13 of the stator 3. A drive 10 is used to drive the rotor 4; this drive 10 includes, for example, an electric motor.

[0083] like Figures 2 to 8 As shown, the stator 3 according to one embodiment can be used for Figure 1 The eccentric screw pump 1 shown.

[0084] The stator 3 is composed of a stator body 15. The stator body 15 is tubularly formed and has a supporting, tubular sheath 19, which has an elastic inner liner 21 on its inner side. The sheath 19 thus has a mechanical support function and is made of a relatively rigid material, while the inner liner 21 is made of a material with elastomeric properties. The stator body 15 has a channel 13 along the longitudinal direction L of the stator, which is used to accommodate the rotor 4. The inner surface 91 of the inner liner 21, which is threaded and wound in a planar manner, surrounds the channel 13 and interacts with the rotor 4 during operation. Figures 3 to 5 As shown in [the image]. Figures 2 to 8 In the illustrated embodiment, the inner surface 91 is either a double-channel threaded surface or a helical winding.

[0085] exist Figures 2 to 8 In this embodiment, both the sheath 19 and the inner liner 21 are made of thermoplastic material and are directly and fixedly connected to each other without the need for a specially provided intermediate adhesive reinforcement layer. Here, the thermoplastic material of the inner liner 21 is thermoplastic elastomer (TPE) or thermoplastic polyurethane (TPU), while polyamide (PA), polypropylene (PP), or thermoplastic polyurethane (TPU) is specifically chosen as the thermoplastic material of the sheath 19. By constructing the supporting sheath 19 from thermoplastic material and providing thermoplastic elastomer or thermoplastic polyurethane for the relatively soft inner liner 21, a strong and reliable bond can be achieved between the sheath 19 and the inner liner 21.

[0086] For example, in Figures 2 to 8 In a variation of the embodiment, the sheath 19 and liner 21 of the stator body 15 are made of the following combination of materials:

[0087] - Sheath 19 is made of PP, and liner 21 is made of TPE; or

[0088] - Sheath 19 is made of PA, and liner 21 is made of TPE; or

[0089] - Sheath 19 is made of PA, and lining 21 is made of TPU; or

[0090] - The sheath 19 is made of TPU, and the lining 21 is also made of TPU.

[0091] In each case, by appropriately adjusting the thermoplastic material, the material of the jacket 19 is designed to be relatively rigid and stiff, while the material of the liner 21 is designed to be relatively soft and flexible. In this way, by appropriately designing the dimensions of the rotor 4, the rotor 4 can form a sealing line with the inner surface 91 of the liner 21, which surrounds the delivery cavity formed between the inner surface 91 and the rotor 4, thereby enabling the eccentric screw pump 1 to build up and maintain pressure. Due to the relatively rigid and stiff design of the jacket 19, the jacket 19 can provide mechanical support to the liner 21 and achieve pressure stability.

[0092] In an exemplary variant of the above embodiments, the liner 21 is made of soft thermoplastic polyurethane, while the sheath 19 is made of rigid thermoplastic polyurethane. Therefore, this stator 3 can be considered to be made of a single material (TPU in this variant). This stator 3 can be easily cleaned after its service life (i.e., when the wear of the stator 3 exceeds a tolerable level) and can be recycled as a whole, for example, by crushing and processing it into reusable thermoplastic granules. Other combinations of thermoplastic materials described above have also proven advantageous in terms of recyclability.

[0093] The liner 21 has an inner surface 91 on its inner side, and when viewed radially from the outside, the liner 21 is connected to the sheath 19 on the inner side of the sheath 19 via a generally threaded connecting surface 28 similar to the inner surface 91 (see [link to relevant documentation]). Figure 3 and Figure 4 ). Figures 3 to 5 As further shown, the liner 21 has a substantially uniform, and therefore at least largely constant, wall thickness t21, which is schematically shown in the figure.

[0094] The sheath 19 also has a threaded outer surface 31 on its outer side, which, in the illustrated embodiment, is also designed as a dual-channel surface. The outer surface 31 is substantially parallel to the connecting surface 28 and the inner surface 91. In this way, the wall thickness t19 of the sheath 19 is designed to be substantially uniform and substantially constant over most of the area of ​​the sheath 19. This saves material, thus conserving resources, and, like the uniform wall thickness t21 of the liner 21, contributes to good manufacturability.

[0095] Figure 2 and Figures 6 to 8The outer surface 31 is shown in various views. The outer surface 31 is divided into multiple partial surfaces designed as threaded segments, some of which are designated, for example, 32, 33, 34, and 35. In longitudinal section, partial surface 32 is a peak face, partial surface 33 is a first sloping descending side face, partial surface 34 is a valley face, and partial surface 35 is a second sloping ascending side face of one of the threads on the outer contour of the stator body 15. One or both end regions of the stator body 15 may have connecting or terminating geometries, such as stepped cylindrical ends 16 and / or 17 (see [reference]). Figure 2 , Figure 6 and Figure 8 Its outer surface is not part of the outer surface 31 of the threaded surface design.

[0096] In the illustrated embodiment, the outer surface 31, designed as a dual-channel threaded surface, is modified in multiple sub-regions by introducing surface portions 36 that have a different shape from the threaded surface.

[0097] To manufacture the stator 3, the stator body 15 is manufactured using a two-component injection molding process or at least a two-stage casting process, which in particular includes two separate injection molding steps.

[0098] The two-component injection molding process for manufacturing the stator body 15 can advantageously and economically be implemented, for example, as a conversion process in a slide-less double-plate mold. Here, the double-plate mold has, for example, two cavities: a first cavity for molding the inner liner 21 and a second cavity for molding the sheath 19. After the inner liner 21 is injection molded, it can be transferred from the first cavity to the second cavity, where it is overmolded with the material used to form the sheath 19 as described above. In a variation of the embodiment, the sheath 19 can be injection molded first using the two-component injection molding process, followed by the injection molding of the inner liner 21, i.e., the inner liner 21 is injection molded onto the sheath 19. Using the two-component injection molding process helps to achieve a good and reliable connection between the outer sheath 19 and the inner liner 21.

[0099] The material used to manufacture the liner 21 is elastic and flexible, as described above, while the sheath 19 requires high rigidity and robust mechanical properties. To prevent undercutting of the threaded outer surface 31 and the rigid material properties of the sheath 19 from hindering the separation of the mold plates in a simple, non-slip double-plate mold, this undercut is eliminated by the surface portion 36 when viewed from the center plane M. The center plane M constitutes the parting surface of the molding die. Therefore, the surface portion 36 serves as a demolding surface, enabling the manufacture of the sheath 19 using a simple mold, thereby helping to reduce manufacturing costs.

[0100] Compared to other areas of the sheath 19 (where the sheath has an unmodified threaded outer surface 31), the wall thickness t19 of the sheath 19 is reduced in the region of the demolding surface 36. This is in Figure 3 The cross-section AA is illustrated schematically and in a simplified manner. For example, in the demolding surface region, the wall thickness t19 can be reduced to approximately 50% of the wall thickness of the sheath 19 in the region of the unmodified threaded outer surface 31.

[0101] The wall thicknesses t21 and t19 shown in the figure are for reference only. The actual wall thickness of the axial normal cross section and the axial parallel longitudinal section may be deformed due to the shape of the threaded surface.

[0102] To eliminate undercuts that may hinder easy separation of the forming tool, see [link / reference]. Figure 2 , Figure 3 , Figures 6 to 8 As shown, the release surfaces 36 are arranged on both sides of the center plane M outside the sleeve 19 relative to the center plane M of the stator 3 (the stator longitudinal axis L is also located within the center plane M), and each release surface is configured to be adjacent to the center plane M. Here, two or more release surfaces 36 are respectively provided on the outer side of the sleeve 19, located on two opposing longitudinal sides 45 and 46 of the stator 3. In particular, for the unmodified threaded surface (the outer surface 31 is formed based on this surface), a release surface 36 is provided on each side of the center plane M each time it passes through the center plane or parting surface M.

[0103] The demolding surface 36 can be designed, for example, to have an arc or curvature, or to be substantially flat. Figures 2 to 8 In some embodiments, see, for example, see Figures 6 to 8 As shown, each demolding surface 36 has a slight curvature, but is composed of parallel generating lines perpendicular to the central plane M. It is conceivable that the demolding surfaces 36 could employ different planar or non-planar designs, as long as they prevent undercutting near the central plane M.

[0104] Additionally, the release surfaces 36 on the two longitudinal sides 45 and 46 are designed and arranged such that the release surfaces 36, or at least a portion thereof, can be used to process the stator 3, stator body 15, or sheath 19, or both, during the manufacture of the stator 3 and / or during the assembly of the stator 3 onto the rotor 4. For example, the release surfaces 36, or a portion thereof, can facilitate the removal of the finished stator body 15 from the molding tool after the sheath 19 has been injection molded.

[0105] For example, the demolding surface 36 can be used here as a mating surface for assembly tools, processing tools, or processing devices. Figure 3The tool or device 55 for assembly or handling is shown schematically and purely as an example. Therefore, the release surface 36 is well-suited for, for example, automatically removing the injection-molded stator body 15 from the molding tool, such as with the aid of a robot and jig as the handling device 55. Furthermore, the release surface 36 simplifies the process of the customer manually or with the aid of assembly tools 55 screwing the stator 3 onto the rotor 4. As mentioned above, the flat or at least partially flat design of the release surface 36 is advantageous for its use in assembly and / or handling, but it is not mandatory; other shapes of the release surface 36 (e.g., slightly curved) can also effectively simplify assembly and / or handling.

[0106] Although the demolding surface 36 described above is preferred for simple and economical manufacturing, in the above reference... Figures 2 to 8 In another variation of the described embodiment, the release surface 36 may be omitted, and a more complex molding tool may be used.

[0107] In the above reference Figures 2 to 8 In another exemplary variant described, the stator body 15 may be manufactured using a two-stage casting process instead of a two-component injection molding process. Here, the sheath 19 is first manufactured independently from the selected material by injection molding, and the finished sheath 19 is subsequently injection molded with an inner liner 21. Thus, the inner liner 21 is formed separately in the sheath 19 by injection molding from the selected thermoplastic material (especially TPE or TPU). Alternatively, in another variant of this embodiment, the inner liner 21 may first be manufactured independently from the selected thermoplastic material (especially TPE or TPU) by injection molding, and then the sheath 19 may be separately formed for the finished inner liner 21 by injection molding in a separate process step.

[0108] In the above embodiments, the sheath 19 is preferably directly connected to the inner liner 21, without the need to apply a special adhesive layer between the sheath 19 and the inner liner 21.

[0109] In the above reference Figures 1 to 8 In other variations of the embodiment, the liner 21 is not permanently and adhesively attached to the sheath 19, but is detachably disposed within the sheath. For this purpose, an inner component 21 is manufactured, designed identically to the liner 21, but used as a separate component. The material used to form the inner component is here a thermoplastic elastomer or thermoplastic polyurethane, and the inner component is made from this material by injection molding. The resulting inner component is then housed as a separate part within the supporting sheath, without adhesive bonding to the sheath, wherein the sheath can be made of the thermoplastic material as described above, or it can be made of metal. For example, in this variation, the geometry of this sheath is designed substantially as follows: Figures 1 to 8 As shown. In this variation, the sheath can be opened or removed to allow internal components made of TPE or TPU to be inserted into the sheath.

[0110] In another embodiment of the invention, the sheath 19 is made of a thermoplastic material, as in the embodiments described above, preferably of a relatively rigid plastic material, while the liner 21 differs from the embodiments described above and is made of a polymeric elastomer. For the sheath 19, a suitable polyamide can be selected as the thermoplastic material, for example, a polyamide produced by Evonik Industries. The liner 21 is made of a rubber material (e.g., synthetic rubber). In this embodiment, the sheath 19 is first injection molded using a selected thermoplastic material, and then the liner 21 is embedded in the sheath 19 by means of elastomer injection molding. In this way, the liner 21 is formed during the injection molding process and can be connected to the sheath 19 during the polymerization or vulcanization of the elastomer. Therefore, in embodiments of the invention, the stator body is also manufactured using a two-component injection molding process or a two-stage casting process. Here, the composition of the thermoplastic material of the sheath 19 is selected such that the liner 21 forms a good bond with the supporting sheath 19, thereby achieving a direct plastic-rubber composite material without the need for a separate adhesive layer.

[0111] In the aforementioned embodiment, the stator body 15 is made of a plastic-rubber direct composite material, and the geometry of the sheath 19 and the inner liner 21 can be as described above. Figures 1 to 8 The structure is formed as described, and is therefore similar to embodiments employing a thermoplastic liner 21, for example, made of TPE or TPU. However, in a variation, where a direct plastic-rubber composite material can be used instead, the thermoplastic sheath 19 is designed as a substantially cylindrical tube with a cylindrical connecting surface that connects to the liner. In this case, the wall thickness of the elastic liner varies.

[0112] Figures 9 to 14 A stator 103 according to yet another embodiment is shown. Except for the differences described below, the stator 103 is designed to be similar to... Figures 2 to 8 The stator 3 shown is the same, and can be used as follows Figure 1 The exemplary eccentric screw pump 1 shown is used in a manner substantially similar to stator 3. The reference numerals for the elements and features in stator 103 corresponding to stator 3 are composed of the reference numerals for the features of stator 3 plus 100.

[0113] The stator 103 differs from the stator 3 primarily in that the sheath 119 of the stator 103 is composed of a thermoplastic material (e.g., polyamide, polypropylene, or rigid TPU) and is provided with external reinforcing ribs 178, 179, 180, and 181, which extend substantially parallel to the longitudinal axis L of the stator body 115 (and therefore also on the stator 103). The reinforcing ribs 178 to 181 enhance the rigidity of the stator 103, preventing it from bending about the transverse axis and improving its resistance to mechanical forces along the longitudinal axis L of the stator.

[0114] When manufacturing the sheath 119, the reinforcing ribs 178 to 181 are specifically covered by the injection molding of the inner liner 121 by injection molding, or, for example, integrally molded with the sheath 119 before the injection molding of the sheath and the inner liner 121 during the injection molding of the sheath 119. Thus, the reinforcing ribs 178 to 181 are made of the same thermoplastic material as the sheath 119.

[0115] The reinforcing rib 181 also has radially extending grooves 185, particularly circular blind holes, which can be used, for example, for fastening or connection by means of screws. The grooves 185 are surrounded by hollow cylindrical enlargements of the reinforcing rib 181, which are also laterally reinforced by additional transverse ribs 182 in a direction transverse to the main extension direction of the reinforcing rib 181, so as to be able to distribute any load input at the location of the grooves 185 into the sheath 119.

[0116] Viewed in cross-section of stator 103, four reinforcing ribs 178 to 181 are evenly distributed around the stator longitudinal axis L at approximately 90-degree intervals and extend radially outward. Although Figures 9 to 14 The example shown only depicts four reinforcing ribs 178 to 181, but it will be understood that variations of this embodiment may include more or fewer reinforcing ribs. For example, only two reinforcing ribs arranged approximately 180 degrees to each other may be provided, or more than four reinforcing ribs may be provided, such as six or eight, which are distributed particularly evenly around the stator circumference.

[0117] According to Figures 9 to 14 In the stator 103 of the embodiment, the liner 121 is injection molded from a thermoplastic material (preferably TPE or TPU) with elastomeric properties.

[0118] exist Figures 9 to 14 In the illustrated embodiment, the central plane M is located at the center of each of the reinforcing ribs 180 and 178 arranged 180 degrees apart. This central plane M coincides with the parting surface of the molding tool (particularly the injection molding tool) used for molding the stator body 115 formed by the sheath 119 and the liner 121. See [reference needed] Figure 13 , Figure 9 and Figure 11 .

[0119] Except for the areas of reinforcing ribs 180 and 178, the release surface 136 is arranged on the outer surface 131 of the sleeve 119 in a manner similar to the release surface 36 to eliminate undercut in the viewing directions of the center plane and the parting surface M. Besides the release surface 136, the areas of reinforcing ribs 178 to 182, and the groove 185, the outer surface 131 and... Figures 2 to 8 Similar to the embodiments in [the text], it is basically designed with a threaded surface, in [the text]. Figures 9 to 14 The outer surface 131 is designed as a dual-channel threaded surface. Therefore, the threaded surface on which the outer surface 131 is based has been modified by reinforcing ribs 178 to 182 and a release surface 136.

[0120] Figure 10 and Figure 11 The cross-sectional view also clearly shows that, with Figures 2 to 8 As in the previous embodiment, the wall thickness t121 of the sheath 121 is substantially constant, which improves the manufacturability of the liner 121 (especially the liner made of TPE or TPU), and the wall thickness t119 of the demolding surface 136 region is reduced compared to other regions of the sheath 119, in which the outer surface 131 is designed to be threaded, which is substantially similar to the description of the wall thickness t19 above.

[0121] The stator 103 can be modified in accordance with the above description of the variant of stator 3. In addition, in another embodiment, it can also be made of plastic-rubber direct composite material in accordance with the above description of the variant of stator 3.

[0122] Although the invention has been fully described above with reference to preferred embodiments, the invention is not limited thereto and can be modified in various ways.

[0123] List of reference numerals

[0124] 1 Eccentric screw pump

[0125] 3. 103 stator

[0126] 4 rotors

[0127] 6. Shell

[0128] 10 drives

[0129] Channels 13 and 113 (Stator)

[0130] 15, 115 Stator Body

[0131] 16, 116 Ends (Stator Body)

[0132] 17, 117 Ends (Stator Body)

[0133] 19, 119 protective sleeve

[0134] 21, 121 Lining or internal components

[0135] 28, 128 connecting surfaces

[0136] 31, 131 Outer surface (sheath)

[0137] 32, 132 Outer surface portion (sheath)

[0138] 33, 133 Outer surface portion (sheath)

[0139] 34, 134 Outer surface portion (sheath)

[0140] 35, 135 Outer surface portion (sheath)

[0141] 36, 136 Demolding surfaces

[0142] 45, 145 First longitudinal side (stator)

[0143] 46, 146 Second longitudinal side (stator)

[0144] 55. Processing tools or assembly tools

[0145] 64. Supply of conveyed materials

[0146] 66 Conveying direction

[0147] 178, 179 Reinforcing ribs

[0148] 180, 181 Reinforcing Ribs

[0149] 182 Transverse reinforcement

[0150] 185 Groove

[0151] 91, 191 inner surface (stator)

[0152] T19 and T119 wall thickness (sheath)

[0153] T21 and T121 wall thickness (lining)

[0154] L Stator longitudinal axis (stator)

[0155] M Center Plane (Stator)

Claims

1. A stator (3; 103) for an eccentric screw pump (1), said stator (3; 103) comprising a stator body (15; 115), said stator body having a supporting sleeve (19; 119) and an elastic liner (21; 121), said liner (21; 121) being disposed on said sleeve (19; 119), wherein, The sheath (19; 119) and the liner (21; 121) are each made of thermoplastic material.

2. The stator for an eccentric screw pump according to claim 1, characterized in that, The stator body (15; 115) is manufactured using a two-component injection molding process.

3. A stator (3; 103) for an eccentric screw pump (1), said stator (3; 103) comprising a stator body (15; 115), said stator body (15; 115) having a supporting sheath (19; 119) and an elastic liner (21; 121), said liner (21; 121) being disposed on said sheath (19; 119), wherein, The sheath (19; 119) is made of thermoplastic material, the liner (21; 121) is made of material with elastomeric properties, and the stator body (15; 115) is manufactured by a two-component injection molding process or at least a two-stage casting process.

4. The stator for an eccentric screw pump according to any one of the preceding claims, characterized in that, The sheath (19; 119) is directly connected to the liner (21; 121).

5. The stator for an eccentric screw pump according to any one of the preceding claims, characterized in that, The liner (21; 121) is formed to have a substantially uniform wall thickness (t21; t121).

6. The stator for an eccentric screw pump according to any one of the preceding claims, characterized in that, The sheath (19; 119) is connected to the liner (21; 121) on the inside by a connecting surface (28; 128), which is at least partially designed as a threaded surface, particularly a double-channel threaded surface.

7. The stator for an eccentric screw pump according to any one of the preceding claims, characterized in that, The sheath (19; 119) has at least partially a threaded outer surface (31; 131) on the outer side, particularly a double-channel threaded outer surface (31; 131).

8. The stator for an eccentric screw pump according to claim 7, characterized in that, The threaded outer surface (31; 131) is modified in at least some areas by an additional release surface (36; 136).

9. A stator (3; 103) for an eccentric screw pump, the stator (3; 103) comprising a stator body (15; 115), the stator body (15; 115) having a sheath (19; 119) and a resilient liner (21; 121), the liner (21; 121) being disposed inside the sheath (19; 119), wherein, The sheath (19; 119) has a threaded outer surface (31; 131) in at least certain areas on the outside, which is modified in at least certain areas by an additional release surface (36; 136).

10. The stator for an eccentric screw pump according to claim 8 or 9, characterized in that, The demolding surfaces (36; 136) are designed to be substantially flat or at least partially substantially flat, or the demolding surfaces (36; 136) are designed to be curved, in particular formed by mutually parallel generation lines.

11. The stator for an eccentric screw pump according to any one of claims 8 to 10, characterized in that, In the region of the demolding surface (36; 136), the wall thickness (t19; t119) of the sheath (19; 119) is reduced compared to other regions of the sheath (19; 119) with the threaded outer surface (31; 131).

12. The stator for an eccentric screw pump according to any one of claims 8 to 11, characterized in that, The stator longitudinal axis (L) of the stator (3; 103) is located within the central plane (M) relative to the center plane (M). The demolding surfaces (36; 136) are arranged outside the sheath (19; 119) and on both sides of the central plane (M). In particular, the demolding surfaces (36) are arranged adjacent to the central plane (M). Alternatively, the sheath (119) is provided with reinforcing ribs (178 to 181) on the outside, and the demolding surfaces (136) are arranged adjacent to at least one reinforcing rib (178, 180).

13. The stator for an eccentric screw pump according to any one of claims 8 to 12, characterized in that, Two or more of the demolding surfaces (36; 136) are respectively disposed on the outer side of the sheath (19; 119) and located on two opposite longitudinal sides (45, 46; 145, 146) of the stator (3; 103).

14. The stator for an eccentric screw pump according to any one of claims 8 to 13, characterized in that, The release surfaces (36; 136) are designed and arranged such that the release surfaces (36; 136) or at least some of them can be used for: The stator (3; 103) or the sheath (19; 119) or both are processed during the manufacture of the stator (3; 103). The stator (3; 103) is processed during the assembly of the stator (3; 103) into the rotor (4) of the eccentric screw pump (1), or The combination of the above processing steps, And it is particularly suitable as or set as a mating surface for processing tools (55) or assembly tools (55).

15. The stator for an eccentric screw pump according to any one of the preceding claims, characterized in that, The lining (21; 121) is made of thermoplastic elastomer or thermoplastic polyurethane.

16. The stator for an eccentric screw pump according to any one of the preceding claims, characterized in that, The sheath (19; 119) is made of polyamide, polypropylene or thermoplastic polyurethane.

17. The stator for an eccentric screw pump according to any one of the preceding claims, characterized in that, The inner liner (21; 121) is made of thermoplastic elastomer, and the sheath (19; 119) is made of polypropylene; or, The inner liner (21; 121) is made of thermoplastic elastomer, and the sheath (19; 119) is made of polyamide; or, The inner liner (21; 121) is made of thermoplastic polyurethane, and the outer sheath (19; 119) is made of polyamide; or, The inner liner (21; 121) is made of soft thermoplastic polyurethane, and the outer sheath (19; 119) is made of rigid thermoplastic polyurethane.

18. The stator for an eccentric screw pump according to claim 4 or any one of claims 5 to 14 in combination with claim 4, characterized in that, The liner (21; 121) is made of polymeric elastomer, and in particular the sheath (19; 119) is made of polyamide.

19. An eccentric screw pump (1) having a rotor (4) and a stator (3; 103) according to any one of the preceding claims, wherein, The stator (3; 103) is designed to interact with the rotor (4) and to at least partially house the rotor (4).

20. A method for manufacturing a stator (3; 103) for an eccentric screw pump (1), said stator (3; 103) being particularly a stator (3; 103) according to any one of claims 1 to 18, wherein, The stator body (15; 115) of the stator (3; 103) is formed with a sheath (19; 119) made of thermoplastic material, and the sheath (19; 119) is provided with an inner liner (21; 121) made of a material with elastomeric properties, wherein the stator body (15; 115) is manufactured by a two-component injection molding process or at least a two-stage casting process.

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