CN104937270B - Rotor for screw pumps and/or eccentric screw pumps, and a screw pump or eccentric screw pump - Google Patents

Abstract

The invention relates to a rotor (1) for screw pumps and eccentric screw pumps, said rotor comprising a rotor head (2) for fixing to a drive and a rotor screw (3), wherein said rotor (1) having a total rotor length (LG). The rotor (1) consists of at least two rotor sections (I, II). The first rotor section (I) comprising the rotor head (2) and a first sub-section (5) of the rotor screw (3) and is made of a solid material, and the at least one second rotor section (II) is designed as a hollow body with an inner hollow region (13).

Description

Rotors for worm and/or eccentric worm pumps and worm or eccentric worm pumps rod pump

technical field

The invention relates to a rotor for a screw pump and/or an eccentric screw pump and to a screw pump or an eccentric screw pump according to the features of the preambles of claims 1 and 12 .

Background technique

Eccentric worm pumps are pumps for conveying large quantities of media, especially viscous, highly viscous and abrasive media such as mortar, liquid manure, oil and grease. Here, the driven, helical rotor rolls on the stator. The stator is a housing whose inner side spirals in the shape of a worm wheel. The rotor here performs an eccentric rotational movement about the stator axis by means of its drawing axis. The outer worm (i.e. the stator) has the shape of a double-start thread, while the rotor worm is only single-start. Rotors are usually constructed of highly wear-resistant materials such as steel. Instead, the stator is constructed of a resilient material such as rubber. Due to the special shaping of the rotor and the stator, a sealed hollow space is produced between the rotor and the stator, which is moved axially forward during the rotation of the rotor and conveys the medium. The shape of the hollow space is constant here, so that the conveying medium cannot be crushed. When properly designed, not only liquids but also solids can be conveyed with the aid of eccentric worm pumps.

DE 2 211 786 A describes a conveying device, in particular a conveying pump having a rotor arranged in a pump housing, wherein a relative rotation of the rotor relative to the pump housing brings about the conveying of a medium located in the housing. On the inner wall of the pump casing, a worm helix extending in a helical shape is processed. The rotor is designed as a cylinder and has a plurality of sealing elements in the region of the worm-shaped structure of the housing. The conveying substance located between the sealing elements is conveyed by the rotation of the rotor in the axial direction.

DE 10 2010 021 592 A1 describes a method for producing a rotor of an eccentric worm pump. The rotor is formed in one piece in a known manner and includes a worm helix and a drive head. In this way, the worm helix produces a smooth surface without machined grooves, thus reducing the risk of damage to the stator housing made of elastic material.

DE 199 25 106 A1 describes a stator for a worm pump or eccentric worm pump with a ceramic casing surrounding a steel core, wherein the casing is produced from at least two rotor casing parts, thus enabling reduced manufacturing costs.

DE 27 07 901 describes an eccentric worm for eccentric worm pumps made of plastic, in which the worm body consists of hardened cast synthetic resin containing fillers. The worm body can be partially hollow in order to save material and reduce weight.

DE 199 25 106 A1 discloses a stator for a screw pump or an eccentric screw pump which has a ceramic rotor housing, wherein the housing is produced from at least two rotor housing parts and can be produced cost-effectively.

EP 2 532 833 A1 describes a delivery element for an eccentric worm pump which has a first thread for providing a first delivery volume and a second thread for providing a second delivery volume.

Contents of the invention

The object of the present invention is to provide a rotor for a screw pump or an eccentric screw pump which, although light, can withstand high loads.

The above object is achieved by a rotor and a worm pump or eccentric worm pump having the features of patent claims 1 and 12 . Further advantageous embodiments are described in the dependent claims.

The invention relates to a rotor for a worm pump and/or an eccentric worm pump, comprising a rotor head and a rotor body for fastening the rotor to a drive. The rotor has a total rotor length. According to the invention, the rotor is formed from at least two rotor regions, in particular a first rotor region and at least one second rotor region, the first rotor region comprising the first partial region of the rotor worm and the rotor head. The first rotor region including the rotor head is made of a solid material, the at least one second rotor region connected to the first rotor region is formed as a hollow body.

The rotor is preferably largely hollow. According to an embodiment of the invention, the first rotor region comprises about 5-40% of the rotor length and the remaining rotor region (which is made up of at least one second rotor region) comprises about 60%-95% of the rotor length. According to a preferred embodiment, approximately 30% to 1/3 of the rotor length is made of solid material, the remaining 2/3 to 70% of the rotor length is formed as a hollow body. According to a further embodiment, approximately 10% of the length of the rotor is made of solid material, the remaining 90% is formed as a hollow body. The solid material is preferably reproduced in the region of the receptacle for the drive, ie in the region of the rotor head, so that the rotor is subjected to the greatest load in this region by the rotary drive force of the motor.

According to an embodiment of the invention, the rotor comprising the rotor head and the rotor worm is made in one piece, eg turned, cast or the like in one piece, and then eg provided with a hollow inner space. For example, a one-piece rotor is produced from a solid material and then hollowed out in the second rotor region by providing a central bore along the rotor longitudinal axis through the second region of the rotor length. The bore is realized at the free end of the rotor opposite the rotor head. This hole can then be closed by means of an end plate in order to prevent transport substances from entering the hollow interior and depositing there. In particular, it can be provided that the hole has a first diameter in a second region, which adjoins the first region containing the rotor head, and that the hole has a third region at the end, opposite the rotor head. has a second diameter, wherein the first diameter is smaller than the second diameter. This is on the one hand determined by the method of manufacture, since the holes are drilled from the free end lying opposite the rotor head. Furthermore, the third end region is therefore designed to be lighter than the second central region and lighter than the first end region, which is designed as a solid material.

According to a further embodiment, a first rotor region comprising the rotor head and the first partial region of the rotor worm is produced individually and subsequently connected to one another, as well as the at least one second rotor region. These regions can each be formed as turned parts, cast parts, precision cast parts or can be produced by forming. According to one embodiment, the first rotor region is produced by means of a different production method than the at least one second rotor region. For example, the first region is a solid material-turned part and the second rotor region is a casting and has a hollow inner region that has been formed during the manufacturing process.

According to another embodiment, the rotor consists of three regions, wherein the first region including the rotor head and the middle region are made as one piece, while the third region at the end is made separately and fixed to the middle region on the free end. The rotor part comprising the first region and the middle region is for example cast in one piece. Subsequently, the central region is drilled from the free end, whereby a hollow body is formed in the central region. For example, the rotor part is cast or otherwise produced, as a third region at the end, the inside of which has been shaped hollow by machining. To connect the two rotor parts, various joining techniques known to those skilled in the art can be used, for example the two rotor parts can be connected to each other in a material-fit manner, glued to each other, screwed together, etc. The connection can be both detachable and non-detachable.

Furthermore, provision can be made for the first rotor region and the at least one second rotor region to consist of different materials. In particular, the first rotor region should consist of a material which is particularly suitable for adequately absorbing the forces acting on the rotor head. According to a further embodiment it is provided that the first rotor region and the adjoining intermediate rotor region consist of a first material, wherein the first rotor region is produced from a material different from the solid material, and the intermediate rotor region is for example formed by Holes may have internal hollow cavities limited by manufacturing conditions. In contrast, the end rotor region is made of a different, preferably lighter material and likewise has an inner hollow space. The two rotor parts are fixed to each other by suitable means.

According to a further embodiment, different rotor regions are designed for different temperature classes. The rotor has in particular at least one diameter perpendicular to the rotor longitudinal axis. According to one embodiment, the rotor comprises at least one first rotor region with a first diameter and a second rotor region with a second diameter, wherein the first diameter and the second diameter are different. The different diameters of the rotor serve to equalize the temperature in the stator elastomer.

In particular, the diameter of the rotor decreases continuously or in steps from the suction side to the pressure side. The increased pressure inside the pump increases the friction of the conveyed substance on the rotor and stator and thus also increases the temperature in the pump. Since the rotor and the stator consist of different materials with different expansion coefficients, eg the stator consists of rubber and the rotor consists of steel or the like, they expand to different extents when the temperature increases. Due to its relatively high coefficient of expansion, the rubber of the stator expands significantly inwards and thus binds the rotor. If solid or abrasive media are additionally conveyed, this can lead to considerable wear of the stator. When conveying a gas-containing medium (the gas is compressed), the temperature increases and a corresponding effect occurs involving the expansion of the stator, since the compression of the gas causes the temperature to rise. In order to ensure reliable operation of the worm pump and/or eccentric worm pump and to avoid dry running and/or to prevent the rotor from becoming stuck in the stator, the diameter of the rotor is reduced continuously or in stages. According to one embodiment of the invention, the diameters of the rotor and the stator are designed in the region of the first rotor in the region of the suction side for a conveyed substance with an average temperature of approximately 40° C. +/−10° C. The diameter of the rotor is preferably reduced in stages and can be designed on the pressure side, in particular in the region of the outlet flange, for example for conveyed substances with an average temperature of approximately 100° C. +/−10° C.

According to an alternative embodiment, the conveyed substance is cooled during conveying by the worm pump and/or the eccentric worm pump, so that the conveyed substance is at a higher temperature on the suction side than on the pressure side. In this case it is advantageous if the diameter of the rotor increases continuously or in steps from the suction side to the pressure side in order to achieve an optimum effect.

As mentioned above, the at least one second rotor region of the rotor is formed by a central rotor region adjacent to the first rotor region with a first outer surface and an end third rotor region with a second outer surface. rotor area. In particular, it can be provided that the shapes of the worm threads on the outer jacket surface are each configured differently. In particular, the outer surface of the intermediate rotor region can have worm-shaped or helical helixes with a first slope and a first mean distance between the helixes relative to one another. In contrast, the end-located third rotor region can have a worm-shaped or helical spiral with a second slope and a second average distance between the spirals. Thus, one obtains delivery lumens of different sizes in these two regions. This embodiment can be advantageously used in particular when conveying multiphase mixtures. With the enlargement of the delivery chamber in the region of the free end of the rotor, possible temperature changes in these regions of the stator are also counteracted (as described above), and thus the efficiency is improved. According to a preferred embodiment, the slope and/or pitch of the helices relative to each other varies in the range of 1% to 5%, preferably in the range of 2% to 4%.

The invention also relates to a screw pump or an eccentric screw pump for conveying a conveyed substance, which has a rotor with a worm-shaped or helically wound outer casing. The rotor is provided with a worm-shaped or helically wound inner casing in the housing. According to the invention, the rotor has the features already described above, in particular consisting of at least two rotor regions, wherein the first rotor region including the rotor head is made of solid material, and the at least one second rotor region is formed as hollow body.

According to a further embodiment it is provided that the rotor comprises at least two rotor regions with differently configured outer casings, and the stator comprises at least two corresponding regions with correspondingly differently configured inner casings.

The rotor can thus be designed to be significantly lighter than a rotor made of solid material. This results in a considerable simplification during installation and operation, especially in pumps with a relatively long construction length, in particular with a rotor length of several meters. Pumps with a long construction length are, for example, pumps used in harbors, in which the delivery chamber between the rotor and the stator is so large that surviving fish can be pumped from the fishing boat to the factory without damaging them. When starting the pump, a so-called breakaway force must be overcome. Breakaway force is the force required to overcome static friction leading to the transition to sliding friction, ie the minimum force required to switch the rotor of the pump from a stationary state to a dynamic state. This partial hollow rotor, which exerts a breakaway force, is significantly smaller than a rotor made of solid material. The pump requires significantly less driving force to operate. Also in smaller pumps, partially hollow rotors can advantageously be used. For example in pumps for conveying yoghurt with fruit, the weight of the rotor must not be too high, otherwise the fruit would be crushed and the whole fruit would not reach the yoghurt carton or the like.

Description of drawings

Exemplary embodiments of the invention and their advantages are explained in more detail below with reference to the drawings. The dimensional ratios of the individual elements in the drawings to one another do not always correspond to the actual dimensional ratios, since some shapes are simplified and other shapes are shown enlarged compared to other elements for better illustration.

Figure 1 shows different embodiments of a rotor according to the invention.

Figure 2 shows a different schematic view of another embodiment of the rotor according to the invention.

Figure 3 shows another embodiment of the rotor according to the invention.

detailed description

For identical or identically acting elements of the invention, the same reference numerals are used. Furthermore, for the sake of visual clarity, only those reference characters that are necessary for the description of the individual figures are shown in the individual figures. These illustrated embodiments are only examples of how the device according to the invention can be constructed and are not definitive.

FIG. 1 shows a respective longitudinal section through different embodiments of a rotor 1 according to the invention. The rotor 1 has a rotor longitudinal axis X and comprises a rotor head 2 intended to be fastened to a drive and a rotor worm 3 which, in connection with a stator (not shown), constitutes a mechanism for conveying substances. delivery cavity. Furthermore, the rotor 1 according to the invention comprises a first region I formed from a solid material and a second region II formed as a hollow body. The rotor has a total rotor length L _G which is the sum of the lengths L _I and L _II of the two regions I and II, or it is the sum of the lengths L ₂ and L ₃ of the rotor head 2 and the rotor worm 3 . This first region I includes the rotor head 2 and is preferably designed significantly shorter than the second region II, ie L _I < L _II .

In the rotor 1a shown in FIG. 1A, the rotor head 2 and the partial region 5 of the rotor worm 3 connected thereto consist of solid material 10, while the remaining region of the rotor worm 3 constitutes a second region II, which The region is designed as a hollow body 12 with a hollow inner region 13 . The hollow inner region 13 is surrounded by a rotor casing 14 which has a casing surface 16 which is designed as a thread-like contour. The first region I is formed, for example, as a solid cast body made of steel, while the second region II with the hollow inner region 13 is additionally produced and fastened to the first region I. The hollow inner region 13 is closed at the free end of the second rotor region II by an end cap 18 . It is thus avoided that transported substances reach and contaminate the hollow inner region 13 of the rotor 1 , 1a. Deposits in the hollow inner region 13 may lead to an unbalance of the rotor 1 , 1a, which may have an adverse effect on the rotational behavior of the rotor 1 , 1a.

Figures 1B and 1C show embodiments of rotors 1b, 1c in which a first region I* of length L _I * substantially only includes the rotor head ₂ of length L2, while a second region of length L _II* II* consists essentially only of the rotor worm 3 of length L ₃ . In particular, it is provided here that the length L I* of the first region I _* or the length L ₂ of the rotor head 2 accounts for approximately 10% of the total length L _G of the rotors 1b, 1c.

Thus in FIGS. 1B and 1C only the rotor head 2 is formed from solid material 10 , while the rotor worm 3 is formed entirely as a hollow body 12 . In particular for the rotor worm 3b in FIG. 1B , the worm-shaped rotor casing 14 consists of a thread-shaped casing surface 16 (for example made of steel or other suitable material) and is connected to the rotor made of solid material 10. Head 2 connected.

For the rotor 1 c according to FIG. 1C , for example, the rotor 1 is made of a solid material 10 . It is drilled from the free end 4 of the rotor worm 3 to the rotor head 2 and thus forms a hollow inner region 13 , so that the rotor worm 3c is now a hollow body 12 . The opening at the free end 4 is closed by means of an end cap 18 .

In the embodiment according to FIGS. 1B and 1C , the rotor head 2 (i.e. about 10% of the total rotor length L _G is thus formed as solid material. Conversely, the remaining 90% of the total rotor length L _G (which in particular corresponds to the rotor The length L ₃ of the worm 3) is configured as a hollow body. Therefore, the rotor 1b, 1c according to the invention is significantly lighter. This can make the installation of the rotor 1b, 1c or the pump simpler. By reducing the starting force when the pump is started, significantly Reduces the drive energy required for pump operation. This reduces the cost of pump operation. In addition, less material is required when manufacturing the pump, thereby reducing the material cost of the manufacturing process. Another advantage is that the lighter rotor 1b , 1c is more economical for transporting substances and only significantly lower rotor radial forces have to be damped in the stator rubber. This generally leads to lower temperatures in the stator rubber and makes an important contribution to operational safety.

Figure 2 shows a different schematic view of another embodiment of a rotor 1d according to the invention. In this rotor _1d , the second area IId with the hollow inner area 13, which mainly comprises the rotor worm 3, is again divided into a central partial area 3-1 and an end partial area 3-2. The rotor worm has a rotor longitudinal axis X and a central diameter D. The region of the rotor worm 3 (which comprises the first region I and the central partial region 3-1) is produced, for example, as a solid casting and is provided with a bore along the rotor longitudinal axis X, which constitutes the center partial region 3-1. Hollow interior region 13-1. On the contrary, the partial region 3-2 at the end is produced as a separate hollow part and is materially, positively or non-positively connected to the free end 4-1 of the partial region 3-1. connected.

Alternatively, the rotor 1 can be produced from one piece. In order to form a hollow shape, a first bore with a first diameter is provided from the free end opposite the rotor head 2 and extends along the rotor worm to a large extent to the rotor head 2 . This hole then expands from the free end through a second hole with a larger diameter, wherein the second hole only extends through the partial region 3 - 2 at the end. In both cases, the ratio between the hollow interior 13 and the rotor housing 14 is greater in the end region 3 - 2 than in the middle region 3 - 1 . In terms of proportion, the end partial area 3-2 comprises a larger inner hollow cavity 13-2 than the middle partial area 3-1, ie the end area 3-2 is designed to be larger than the middle partial area 3-1. -1 is lighter. The free ends of the end-located partial regions 3 - 2 can also be closed by means of end caps 18 .

FIG. 3 shows another embodiment of a rotor 1 e according to the invention, which is largely similar to the rotor 1 d of the embodiment shown in FIG. 2 . In this rotor 1 e, the second area II _e with the hollow inner area 13 , which essentially comprises the rotor worm 3 , is again divided into a central partial area 3 - 1 and an end partial area 3 - 2 . The region of the rotor worm 3 (which comprises the first region I and the middle partial region 3-1) is produced, for example, as a solid casting and is provided with a hole along the rotor longitudinal axis X, which constitutes the middle part region 3-1. Hollow interior region (see also Figure 2A). On the contrary, the partial region 3-2 at the end is produced as a separate hollow part and is materially, positively or non-positively connected to the free end 4-1 of the partial region 3-1. connected.

The rotor has a first diameter D ₁ in the local area 3-1 and the rotor has a second diameter D ₂ in the local area 3-2. The second diameter D ₂ is preferably smaller than the first diameter D ₁ . Different expansions of the rotor and the stator in this region due to the friction-induced temperature rise can thus be effectively compensated.

In the embodiment shown, it can also be seen that the shape of the worm thread 17 on the outer casing surface 18 is configured differently in each of the partial regions 3 - 1 , 3 - 2 . In particular, the outer surface 18 - 1 of the intermediate rotor region 3 - 1 has worm-shaped or helical helices 17 - 1 with a first slope and a first mean distance A ₁ between the helices. In contrast, the third rotor region 3 - 2 at the end has worm-like or helical helices 17 - 2 of a second slope and a second average distance A ₂ between the helices. Thus, in the two regions 3 - 1 , 3 - 2 , between the rotor 1 e and the (not shown) stator, one obtains delivery chambers of different sizes. The transition region between the middle rotor region 3-1 and the third rotor region 3-2 has a so-called transition pitch And thus constitute the delivery cavity of different sizes.

The invention has been described with reference to preferred embodiments. However, it is conceivable for professionals that the present invention can be modified or changed without departing from the protection scope of the following claims.

List of reference signs

1 rotor

2 rotor heads

3 rotor worm

3-1; 3-2 local area

4 free ends

5 local area

10 solid materials

12 hollow body

13 Hollow interior area

14 Rotor housing

16 Outer surface

17 Worm thread/helix

18 end caps

A Spacing between rotor helices

I first area

II Second area

L length

X rotor longitudinal axis

Claims (15)

1. A rotor (1) for a worm pump and/or an eccentric worm pump, comprising a rotor head (2) and a rotor worm (3) for fixing the rotor on a drive, wherein the rotor (1) has a total rotor length (L _G ), characterized in that the rotor (1) consists of at least two rotor areas (I, II), wherein the first rotor area (I) comprises a first partial area of the rotor worm (3) (5) and said rotor head (2), and the first rotor region is made of solid material, wherein at least one second rotor region (II) is formed as a hollow body; wherein the first rotor region (I) comprises 5-40% of the total rotor length (L _G ), and wherein the at least one second rotor region (II) comprises 60%-95% of the total rotor length (L _G ) %; and wherein at least one second rotor region (II) comprises a central partial region and an end partial region, wherein the central partial region is formed integrally with the rotor head (2) and has a longitudinal direction along the rotor (1) The central bore of the axis (X), wherein the partial regions of the ends are formed as hollow bodies. 2. The rotor (1) according to claim 1, wherein the first rotor region (I) comprises 30% of the total rotor length (L _G ). 3. The rotor (1) according to claim 1, wherein the at least one second rotor region (II) comprises 70% of the total rotor length (L _G ). 4. The rotor (1) according to claim 1, wherein the rotor (1) including the rotor head (2) and the rotor worm (3) is formed in one piece. 5. The rotor (1 ) according to claim 4, wherein the at least one second rotor region (II) has a central hole along the rotor longitudinal axis (X). 6. The rotor (1) according to claim 1, wherein the first rotor region (I) and the partial region of the end of the at least one second rotor region (II) are each produced individually and connected to each other, The first rotor region comprises the rotor head (2) and a first partial region (5) of the rotor worm (3). 7. The rotor according to claim 6, wherein the first rotor region (I) and at least one second rotor region (II) are turned, cast, precision cast or formed components. 8. The rotor (1) according to claim 6 or 7, wherein the first rotor region (I) and at least one second rotor region (II) are made in a different manner. 9. The rotor (1) according to claim 8, wherein the first rotor region (I) and at least one second rotor region (II) consist of different materials. 10. The rotor (1) according to claim 6, wherein said rotor (1) has at least one diameter (D) perpendicular to the rotor longitudinal axis (X), and wherein at least one first rotor region (I ) and the at least one second rotor region (II) each have a different diameter (D ₁ , D ₂ ) for temperature compensation in the stator elastomer. 11. The rotor (1) according to claim 6, wherein said at least one second rotor region (II) comprises: adjacent to the first rotor region (I) having a first outer casing surface (16-1 ) at least one intermediate rotor region (3-1); and a third rotor region (3-2) at the end with a second outer shell surface (16-2). 12. The rotor (1) according to claim 11, wherein the outer casing surfaces (16-1; 16-2) of the middle rotor region (3-1) and of the third rotor region (3-2) at the end and wherein the third rotor region (3-2) at the end comprises worm-like or helical helices of a second slope and also comprises a second average spacing between the helices. 13. The rotor (1) according to claim 12, wherein the outer casing surface (16-1) of the intermediate rotor region (3-1) comprises a worm-like or helical helix of a first slope and further comprises a helix The first average distance between lines. 14. A worm pump or eccentric worm pump for conveying transported substances, which has: a rotor (1) with a worm-shaped or helically spiraled outer casing (16); and a housing forming a stator, the housing The body has a worm-shaped or helically coiled inner surface; it is characterized in that the rotor (1) has the characteristics according to any one of claims 1-13. 15. Worm pump or eccentric worm pump according to claim 14, wherein the rotor (1) comprises at least two outer casing surfaces (16-1; 16-2) according to claim 12 having different configurations The rotor region (3-1; 3-2), and wherein the stator comprises at least two corresponding regions of the inner casing having correspondingly different configurations.