KR101728260B1 - Multiple pump arrangement - Google Patents

Abstract

The present invention relates to an adaptive eccentric screw pump, which permits increased transport capacity and pressure and / or simultaneous transport of more than one conveying medium, as required, wherein the energy consumption of the eccentric screw pump (2) Is relatively small, and the manufacturing cost and the management cost are also kept low. To this end, a modular conveying system is mounted on the eccentric screw pump 2 according to the invention, which comprises two or more conveying (conveying) conveyors each comprising one rotor 10 and one stator 8 Wherein the conveying modules 4, 6, 38 and 40 are connected to each other and the conveying system is assigned only one driving device 14, The transfer system for the transfer medium comprises one or more inlets and / or outlets (18, 24) or one or more modular perfusion housing (12).

Description

[0001] MULTIPLE PUMP ARRANGEMENT [0002]

The present invention relates to an eccentric screw pump.

Eccentric screw pumps are used in a variety of applications, for example agriculture, chemical industry, grocery industry and paper industry. The eccentric screw pump belongs to the group of rotating positive displacement pumps and consists essentially of a rotor and a stator in addition to the drive unit. The screw type rotor of the eccentric screw pump has a large pitch, a deep channel depth and a small core diameter. The stator has one more threaded channel than the rotor, and its pitch length is twice that of the rotor. A transfer space is formed between the stator and the rotor and the transfer space is continuously moved from the inlet side to the discharge side so that the transfer medium can be conveyed in the transfer space.

The rotor of the eccentric screw pump is typically made of a material resistant to abrasion, such as, for example, steel. Alternatively, the stator is generally made of an elastic material such as, for example, rubber. However, in the prior art, stators made of a material or a material composite such as metal and / or plastic are also known.

The individual parts of the eccentric screw pump are dimensioned corresponding to the respective transfer operations. For example, the transferable and reachable pressure is determined by the size and configuration of the stator and rotor. Thus, the drive system can be designed and constructed in the same manner, for example, even when two eccentric screw pumps are used completely differently. Particularly, the eccentric screw pump can reach different transfer capacities and pressures even when the number of revolutions of the rotors is the same. For example, if the requirements for the eccentric screw are changed, the eccentric screw pump can be replaced only because the pump is no longer suitable for this, due to the increased target displacement capacity, because the retrofitting process is very complicated .

For example, US 2,438,370 discloses an eccentric screw pump having a plurality of cylinders which are fixedly integrated within a housing and in which a rotor gear is also arranged. It is deemed desirable that the pump requires only one seal due to its construction. Since the pump has only one exhaust port 29, the pressure for all the transfer modules can not be changed. As the feed module is affected by the eccentricity that must be compensated by the internal gear, the feed rate is consequently limited and the pump is exposed to high wear. The pump has only one inlet port 28 only for the transfer medium and the modules are replaced in pairs at relatively high cost due to the compact construction and the unusual drive arrangement.

Also known is an eccentric screw pump with two or more pump stages connected in series (US 5,820,354). The volumetric flow of the second pump is smaller than the volumetric flow of the first pump. Such an embodiment enables compensation of the transport medium by cooling the pump using a cooling system 55 disposed between the pump stages. Depending on the cooling action on the conveying medium, the volume of the cooling medium can be reduced and smaller pump stages can be connected in series. The transfer direction and the inlet and the outlet for the transfer medium of the pump device together with it can not be changed.

One or more internal pump rotors are surrounded by one or more external pump rotors and have two pump sections Pa and Pb in which case these pump sections Pa and Pb are driven by different rotations of the rotor The eccentric screw pump is disclosed in WO 2009/038473 Al. This pump has an inlet (inlet flange 21) and an outlet (outlet flange 28) for transferring the fluid.

However, it is desirable to provide a pump that is simple and yet low cost and can be adapted for individual transfer operations. In addition, such a pump must be capable of simultaneous transfer of a variety of products without requiring a plurality of separate pumps or pump devices for this purpose. Also, the load of the parts associated with the conveyor of the pump should not be significantly higher than with conventional eccentric screw pumps.

However, known eccentric screw pumps or eccentric screw systems are not well suited for such purposes.

An object of the present invention is to provide an eccentric screw pump capable of increasing the transfer capacity and pressure and / or simultaneously transferring one or more transfer media as required, wherein the eccentric screw pump And the manufacturing cost and the maintenance cost of the eccentric screw pump are also kept low.

This problem is solved in accordance with the invention by means of an eccentric screw pump equipped with a modular transport system having two or more transport modules each comprising one rotor and one stator, The transfer system is assigned only one drive and the transfer system has one or more inlets and / or outlets or one or more modular perfusion housings for one transfer medium.

At this time, the rotor / stator assembly carrying the conveying medium is considered as the conveying module. By the use of an eccentric screw pump and one or more transfer modules according to the invention, the same products as well as different products can be transferred simultaneously, as well as different products. In addition, by connecting a plurality of feed modules in series, the reachable pressure of the pump can also be increased. To this end, the conveying modules are coupled to each other such that only one driving device is required for driving these conveying modules.

The present invention originates from the idea that adaptation to individual transport operations can be implemented particularly simply by a modularly configured transport system. In this case, the inlet and outlet for the conveying medium and the number of conveying modules must be substantially arbitrarily expandable and combinable. With the construction kit system thus provided, the pump can be effectively matched to the requirements of the user.

Such a matching situation is achieved by connecting two or more transport modules to one another. The transfer module comprises one stator and one rotor, respectively, in which case the rotor is driven by only one drive. To this end, the rotors are connected to one another in order to transmit the forces generated during the operation of the eccentric screw pump, in particular the torque generated by the drive. In this case, the conveying module is preferably connected to each other such that a phase difference of 180 DEG is produced between the vibrations caused by the pressure pulsation depending on the individual rotors and the rotation angle of this conveying module. Since the vibration frequency is the same due to the use of only one drive system, vibration is minimized.

Preferably, the transfer module is connected to each other via a suction housing, a pressure housing or a perfusion housing. An advantage of such a connection method is that the eccentric screw pump can be assembled according to the transfer operation. At this time, the suction housing and the pressure housing are provided with connection pipes for connection with the transfer line. Thereby, the suction housing can be connected to the suction line, and the pressure housing can be connected to the pressure line.

By suitably combining and selecting the housings, the adaptation or modification of the eccentric screw pump is possible at relatively low cost in accordance with the individual transfer operations. The transfer module may optionally be connected to the pressure housing, the suction housing or the perfusion housing, and finally the transfer module may be provided with a pressure housing or a suction housing. In addition, since the transfer module can be implemented differently, the transfer capacity of the transfer module becomes different even if the rotational frequency of the rotor is the same. Once the different products have been transferred, certain mixing ratios can be adjusted.

The rotor assigned to the transfer module is preferably connected to each other through the rigid connector inside the housing, so that the transfer of the force acting on the rotor by the drive device is possible without gap and without loss. The rotors may be connected by respective rigid connectors or rigidly formed connectors known in the prior art and these connectors are suitable for delivering torque, or torque, and axial forces, depending on the application. For example, in this case, a material-bonded connection, such as a welded connection, a gummed connection or a soldered connection, or a forced and / or shaped coupled connection such as a screw connection, a clamped connection or a pinned connection is mentioned. Of course, the rotors can also be interconnected by joints.

In one preferred embodiment, the rotors are releasably connected to one another. As a result, assembly and disassembly of the conveying modules is simplified and improved. Therefore, the eccentric screw pump according to the present invention can be modified in accordance with the modified transfer operation.

In yet another embodiment, it is proposed to integrally form the rotors for two or more transport modules. Such structural features are particularly well suited for the transport of, for example, abrasive and corrosive media, since there is no connection site. When assembled, the housing and the stator slide through the integral rotor. In this particular embodiment, the stator is regarded as a transport module even though the transport module performs its function together with the individual rotor sections after assembly.

The eccentric screw pump is preferably formed such that the axial force F acting in the direction of the drive device is approximately zero or at least reduced. This is realized when two rotations of the rotors are the same and a direction of rotation is the same, each of the two conveying modules being conveyed in the opposite direction. To this end, the transport modules have a pitch in the opposite direction. For example, in an eccentric screw pump having two feed modules, one feed module has a left pitch and the other feed module has a right pitch. During the operation of the eccentric screw pump, the axial forces acting on the respective conveying modules act in opposite directions, and when the same kind of conveying module is used, they are almost completely extinguished. The expression " homogeneous " can be understood as a fixed embodiment of the transfer element and dimensional design, except for the different pitches. Since the resulting axial force on the drive side is approximately zero, the cost-intensive bearing element of the drive, for example consisting of one pump housing with substantially one drive and connection, Element. ≪ / RTI > As a result, the total load of the drive device is remarkably reduced.

Particularly preferably, in the eccentric screw pump proposed herein, the transfer modules are arranged in series. Thereby, torque transmission from the drive to the rotor (s) can be kept very simple. This is also possible, for example, by integrally forming the rotor as already proposed above. Thus, in this embodiment, only one rotor is needed for all the transfer elements of the eccentric screw pump.

In another preferred construction, the two neighboring conveying modules are connected to one another through a single flow-through housing and are formed so that the conveying directions are the same. To this end, the pitches in the two feed modules are the same, preferably the feed modules have one left pitch. More specifically, the product is conveyed through the inlet tube of the pump housing into the first conveying module and is conveyed in one direction through the perfusion housing and the second conveying module. Since each conveying module is a pressure end, the resultant pressure may be increased by a plurality of conveying modules connected in series.

It may also be desirable to couple two neighboring conveying modules together via one suction or pressure housing, in which case the conveying modules are formed for the opposite conveying directions. To this end, the pitches of the two transfer modules are different. Thus, since the eccentric screw pump includes a first feed module with a left pitch and a second feed module with a right pitch, the two feed modules being coupled together via a single pressure housing, And is conveyed to the pressure housing through the conveying medium. In the second embodiment, the eccentric screw pump includes a first conveying module having a right pitch and a second conveying module having a left pitch. In this case, two conveying modules are connected through one suction housing, Is sucked through the conveying module and conveyed in the opposite direction.

In one preferred embodiment, the eccentric screw pump comprises only two transfer modules. Even when only two transfer modules are used, the eccentric screw pump can be configured to correspond to the individual requirements for the transfer operation, yet still have a compact structural shape.

For example, an eccentric screw pump can be configured to reach twice the transfer capacity at an unchanged normal pressure, when the eccentric screw pump has the same number of revolutions and rotational direction as a conventional eccentric screw pump . To this end, the first conveying module connected to the driving device has a left pitch, and the second conveying module connected in series has a right pitch. The two conveying modules are coupled together via a single pressure housing. The second transfer module has a suction housing at its end facing the pressure housing. As with conventional eccentric screw pumps, the transfer medium is sucked through a suction tube in the pump housing, but is also sucked through a suction tube in the suction housing. In other words, the transfer medium is transferred from the two sides to the pressure housing in the operating state of the pump, and is discharged through one pressure tube in the pressure housing. In this manner, different transport media can also be supplied. In this case, the conveying or conveying media are guided together, in which case the mixing ratio can be adjusted by appropriately selecting the conveying module.

However, as in the case of a conventional eccentric screw pump, it is also possible to construct an eccentric screw pump which reaches a pressure twice as high as a normal transfer capacity. To this end, the eccentric screw pump is provided with two feed modules having the same pitch, preferably the left pitch. The two transfer modules are coupled together through a single flow-through housing. The second transfer module has a pressure housing at its end facing the perfusion housing. In this variation, the conveying medium is sucked through the suction pipe of the pump housing, and is conveyed via the first conveying module, the perfusion housing and the second conveying module toward the pressure housing provided with the pressure tube.

In yet another variant, the eccentric screw pump comprises a total of four transfer modules. Thereby, according to the configuration, four times the feed amount can be reached when the pressure is not changed, or twice the feed amount when the pressure is double, as compared with the conventional eccentric screw pump.

To reach four times the feed rate, each of the two feed modules with different pitches are connected to one another via a single pressure housing, and the two pairs of feed modules thus formed are connected to one another again through one suction housing. Another suction housing is disposed at the end of the eccentric screw pump facing the drive. Thus, the transport medium can be transported through a total of three suction pipes and two pressure pipes. The transport module preferably includes first through fourth transport modules having left-right-left-right pitches.

In another preferred embodiment, in addition to the preferred embodiment of an eccentric screw pump with a total of four transfer modules, in which the pump system comprises two suction housings and two pressure housings, the transfer module comprises one suction housing, The housing and the single pressure housing. Each of the two conveying modules having the same pitch is connected to one another through a single flow-through housing, and the two conveying module pairs thus formed are again connected via a single pressure housing. At the end of the eccentric screw pump facing the drive, a suction housing is disposed. These transfer modules preferably have a left-left-right-right pitch.

Preferably, the eccentric screw pump has mixing means connected to the rotor in the connection area of the feed module. Thereby, it becomes possible to mix the conveying medium or the conveying medium during conveyance. This situation is particularly advantageous when two different products are introduced into the eccentric screw pump, for example one product through the first suction housing and another product through the second suction housing. For particularly effective mixing of the products, the mixing means are arranged inside the pressure housing and are directly coupled to the rotor. Therefore, no separate driving device is required.

According to one preferred refinement, the housings are formed substantially identically. In particular, the suction housing and the pressure housing are identical and are specified only by the manner in which they are used. Alternatively, the perfusion housing is preferably formed from a suction housing or a pressure housing by providing a closure means in the suction or pressure tube. For example, the closure means may be formed as a blind flange secured to the housing tube via a flange connector.

The advantages achieved by the present invention are, in particular, the fact that the transfer of different conveying media of a predefined specific mixing ratio can be realized by a single pump system. At this time, the pump system can be particularly easily adapted to the transfer operation by the number and selection of the transfer module and the connection means. Because of the fact that the feed rate and feed rate in the eccentric screw pump are determined and influenced by various factors such as the geometry and pitch of the rotor and the stator, the feed rate can be particularly simply controlled by the modular pump structure . By using a transport module having different transport capacities, the mixing ratio of the transport media can be influenced. Cost savings are also possible. The energy cost and the material cost can be reduced because the modular structure of the eccentric screw pump according to the invention is sufficient without coupling rods and joints so that the number of parts moved in the conveying medium This is because it is relatively small. As a result, the frictional forces that negatively affect pump efficiency and pump life are also reduced. The transfer module can be arranged such that the axial forces are almost completely canceled. When the rotational direction of the rotor (s) is reversed, the conveying direction can be changed.

Another advantage is that only one sealing system at the suction side of the drive system is required and only this sealing system needs to be managed.

For example, when the diameter of a tube or a borehole or a hole is the same, if the eccentric screw pump according to the present invention is used as a so-called submerged pump, the feed amount can be doubled.

Embodiments of the present invention are described by way of example with reference to the accompanying drawings. Explanation of drawings:
1 is a schematic view showing an eccentric screw pump having two conveying modules connected to each other through a single flow-through housing and one pressure housing disposed at an end thereof,
Fig. 2 is a schematic view showing an eccentric screw pump having two transfer modules which are connected to each other through a single pressure housing and which are provided with one suction housing at an end thereof,
Fig. 3 is an exploded perspective view of an eccentric screw having two conveying modules which are connected to each other through a single pressure housing and whose one end is provided with a pressure housing, Fig. 3 is a schematic view showing a pump,
Fig. 4 is a schematic view showing an eccentric screw pump having four transfer modules connected to each other through one suction housing and two pressure housings, one suction housing being disposed at an end thereof,
5 is a schematic diagram showing an eccentric screw pump with four transfer modules connected to each other through one pressure housing and two flow-through housings and one suction housing at the end thereof, and
Figure 6 is a schematic diagram showing a prior art transport system in which a total of four eccentric screw pumps are connected in parallel.

The apparatus according to figure 1 comprises a first and a second conveying module 4, 6 comprising one stator 8 and one rotor 10, each connected via a flow-through housing 12 The eccentric screw pump (2) is shown. At the end of the eccentric screw pump 2 opposed to the drive device 14, the second feed module 6 is provided with a pressure housing 16 having a pressure tube 18. The two transfer modules 4, 6 are structurally implemented identically and have a left pitch L. The perfusion housing (12) is a pressure housing or a suction housing provided with a closure means (20). Closure means 20 must be placed behind the pressure housing to disadvantageously act on the flow waveform and avoid dead volume within which the transfer medium may sink.

The eccentric screw pump 2 is provided with a pedestal not shown in this embodiment. At this time, the tube of the perfusion housing 12, which is not used for transfer, may be used as a pedestal in a preferred manner, or it may be used as a base for assembling the pedestal.

The transfer system consisting essentially of the transfer modules 4 and 6 and the housings 12 and 16 is coupled with a drive device 14 which comprises a pump housing 22 with a suction pipe 24, (26). The transfer of force to the rotor 10 of the first transfer module 4 is effected by the drive shaft 30 coupled through the joint 28. Further, in order to prevent the conveying medium from reaching the outside, the driving device 14 is provided with the sealing portion 32. [

The rotors 10 of the conveying modules 4, 6 are connected to each other via a single rigid coupling 34. [ During operation of the eccentric screw pump 2, the transfer medium is transferred from the suction line, not shown in the present embodiment, through the suction tube 24 into the pump housing 22 and by the transfer module 4, To the pressure housing 16 and then through the pressure tube 18 in this pressure housing to the pressure line not shown in this embodiment. The axial force generated at this time acts in opposition to the conveying direction and is accommodated by the bearing provided for this purpose. In this embodiment, since the feed modules 4, 6 are connected in series, the pressure of the feed screw is twice as high as that of the conventional eccentric screw pump in which only one rotor / stator assembly is installed.

An eccentric screw pump 2 with two transfer modules 4, 6 connected through a single pressure housing 16 is shown in Fig. The first conveying module 4 has a left pitch L and the second conveying module 6 has a right pitch R. [ The rotors 10 are connected to each other via a single rigid coupling 34. At the end of the eccentric screw pump 2 opposed to the drive device 14, a suction housing 36 provided with a suction pipe 24 is disposed. Like the eccentric screw pump 2 shown in FIG. 1, the pump housing 22 has another suction pipe 24.

Due to the different left-right pitches L and R of the transfer modules 4 and 6, the housing arranged at the end of the eccentric screw pump 2 acts as the suction housing 36. Thereby, the conveying medium is conveyed through the two suction pipes 24 into the pressure housing 16, and is conveyed through the pressure pipe 18. The conveying medium is conveyed in the opposite direction, even though the direction of rotation of the rotors 10 driven by the common drive device 14 is the same. As a result, the axial force acting during rotation of the eccentric screw pump 2 and acting on the rotation 10 is blocked, whereby the resulting force acting on the bearing of the drive system 14 is approximately zero or at least equal to zero It decreases. At this time, the coupling 34 for the rotor 10 must be designed to absorb the tensile force generated. Thereby, the drive shaft 30, the joint 28 and the bearing 32 are preferably subjected to less load, resulting in less wear. Further, the parts of the eccentric screw pump 2 can be dimensionally designed correspondingly and cost-effectively. Mixing means are arranged in the region of the coupling 34 in the pressure housing 16, which is connected to the rotor and is formed as a stirring element 37. In this embodiment, since the conveying modules 4 and 6 are connected in parallel, the conveying capacity reaches twice as much as that of the conventional eccentric screw pump.

As an alternative embodiment not shown in the present embodiment and shown in the example of Fig. 2, the rotor 10 may be integrally formed. Thereby, the coupling 34 can be omitted. To this end, the rotor 10 has two sections for the conveying modules 4, 6. In other words, it has a first section with a left pitch L and a second section with a right pitch R. [

3 shows an eccentric screw pump 2, which is the eccentric screw pump 2 shown in Fig. 2, but which includes another drive device 14. Fig. The drive has a compensating coupling (33) for transferring torque to the rotor. Due to the compact construction of the drive device 14, the extended structural configuration of the eccentric screw pump 2 connecting the feed modules 4, 6 in series can be almost completely compensated.

Figure 4 shows an eccentric screw pump 2 with a total of four transfer modules 4, 6, 38, 40, in which case the pressure housing 16, similar to the embodiment of Figure 2, The two transfer modules connected to each other are connected to the suction housing 36 so that the transfer modules 4, 6, 38, 40 of the transfer system start from the drive device 14 and have a left-right-left- Lt; / RTI > At the end of the eccentric screw pump 2 opposed to the drive device 14, a suction housing 36 having a suction pipe 24 is disposed. The rotors 10 are connected to each other by a rigid coupling 34. The conveying medium is conveyed through a total of three suction pipes 24 and two pressure pipes 18. In this embodiment, since the four conveying modules 4, 6, 38 and 40 are connected in parallel, the conveyance capacity reaches four times the conventional eccentric screw pump. Since the number of conveying modules 4, 6, 38, 40 with the left pitch and the right pitch is the same, the resulting force acting on the bearing of the drive 14 is approximately zero or at least reduced.

Another alternative embodiment with a total of four transfer modules 4, 6, 3840 is shown in Fig. In this embodiment, two pairs of transfer modules, namely a first transfer module pair (4, 6) and a second transfer module pair (38, 40), which are interconnected and connected in series via a single flow-through housing (12) Are coupled to each other by a pressure housing (16). As a result of the series of connected transfer module pairs 4, 6 and 38, 40 having different pitches, the transfer system will eventually have transfer modules 4, 6, 38, 40 with a left-left-right- 40).

During operation of the eccentric screw pump 2, the transfer medium is sucked by the suction tube 24 in the suction housing 36 and the pump housing 22, and is transported through only one pressure tube 18. In the present embodiment, two transfer modules are connected in series, and two pairs of transfer modules formed thereby constitute one parallel circuit. Therefore, compared to the conventional eccentric screw pump, the transfer capacity is twice the transfer capacity and twice the pressure . Since the number of conveying modules 4, 6, 38, 40 with the left pitch and the right pitch is the same, the resulting force acting on the bearing of the drive 14 is approximately zero or at least reduced.

In FIG. 6, an assembly having a plurality of conventional eccentric screw pumps 42 known in the prior art and structurally identical is shown for comparison. A total of four eccentric screw pumps 42 are connected in parallel in order to reach the feed capacity four times as large as the normal eccentric screw pump, as can be seen from the flow waveform of the conveying medium shown by the broken line. Compared to the modularly configured eccentric screw pump 2 according to the present invention, the assemblies known in the prior art have, among other things, an undesirably high energy demand for operating the pump, high manufacturing and management costs, Resulting in demand.

Each of the four eccentric screw pumps 42 includes one each of a pressure housing 16 disposed at the end facing the drive 14, the rotor / stator assembly 44 and the drive device 14, A pressure tube (18) is provided in the housing. The conveying medium is sucked through the suction pipe 24 in the pump housing 22 and conveyed in the direction of the pressure housing 16 through the pressure pipe 18 to the inside of the pressure line Lt; / RTI >

The device according to the invention is particularly directed to an eccentric screw pump 2 which can be used flexibly but which can also reduce cost and complexity. Due to the particularly modular construction, the number and selection of suitable transport modules 4, 6, 38, 40 and housings 16, 36 allows the eccentric screw pump 2 to be adjusted for individual transport operations . Only a single drive unit 14 is required for this purpose, thereby keeping energy demand and management demand relatively low among others. In addition, by alternately arranging the transfer modules having different pitches (L, R), the axial direction acting on the bearings of the eccentric screw pump can also be reduced.

02: Eccentric screw pump
04: 1st feed module
06: 2nd conveying module
08: Stator
10: Rotor
12: Perfusion housing
14:
16: Pressure housing
18: Pressure tube
20: closing means
22: Pump housing
24: suction pipe
26: Driving parts
28: Joint
30: drive shaft
32: Sealing part
33: compensation coupling
34: Coupling
36: Suction housing
37: stirring element
38: Third conveying module
40: Fourth conveying module
42: Eccentric screw pump (prior art)
44: Rotor / stator assembly (prior art)

Claims (19)

An eccentric screw pump equipped with a modular transfer system having two or more transfer modules each comprising one rotor and one stator,
The transfer modules are interchangeable in the pump, can be replaced by other transfer modules,
The transfer modules are connected to each other and a single drive is assigned to the transfer system irrespective of the structure of the modules in the pump for all the modules,
The transport system may be used for at least one transport medium
(i) one or more entrances
(ii) one or more outlets
(iii) one or more modular perfusion housing
, ≪ / RTI >
The modular perfusion housing is separate from at least two feed modules but can be located therebetween,
The rotors of the transfer modules are connected to each other through a rigid connector,
Wherein the rotors are disengageably connected to each other. 2. The apparatus of claim 1 wherein each of the transfer modules comprises a suction housing having an opening including an inlet, a pressure housing having an opening including an outlet,
The suction housing, the pressure housing, the perfusion housing are housings of substantially the same structure,
Wherein an opening of the flow-through housing is provided with a closing means. 3. An eccentric screw pump as claimed in claim 1 or 2, wherein the rotors for the transfer modules are integrally formed. 3. An eccentric screw pump according to claim 1 or 2, wherein the axial force acting in the direction of the drive device is zero. 3. An eccentric screw pump according to claim 1 or 2, wherein the transfer modules are arranged in series. 3. The eccentric screw pump according to claim 1 or 2, wherein two neighboring transfer modules are connected to each other via one suction housing or pressure housing and the transfer directions are opposite to each other. 3. An eccentric screw pump according to claim 1 or 2, wherein two neighboring transfer modules are connected to each other through a single flow-through housing and are configured to have the same transfer direction. 3. An eccentric screw pump as claimed in claim 1 or 2, wherein the transport system comprises two transport modules. The eccentric screw pump of claim 8, wherein the transfer system comprises one pressure housing and one suction housing. The eccentric screw pump of claim 8, wherein the transfer system comprises one pressure housing and one flow-through housing. 3. An eccentric screw pump as claimed in claim 1 or 2, wherein the transfer system comprises four transfer modules. 12. The eccentric screw pump of claim 11, wherein the transfer system comprises two suction housings and two pressure housings. 12. The eccentric screw pump of claim 11, wherein the transfer system comprises one suction housing, two flow-through housings and one pressure housing. 3. An eccentric screw pump according to claim 1 or 2, wherein mixing means associated with the rotor is arranged in the connecting region of the conveying modules. 15. The eccentric screw pump of claim 14, wherein the mixing means is disposed within the pressure housing. A housing for a transfer system of an eccentric screw pump according to claim 1 or 2, wherein the transfer modules of the eccentric screw pump are connected to each other. delete delete delete

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