ECCENTRIC SCREW PUMP WITH MAGNETIC COUPLING

Abstract

An eccentric screw pump with a rotor of a pump drive shaft circling essentially about a fixed axis relative to a stator in a bearing block, which pump drive shaft is rotationally driven by a motor drive shaft of a motor, a power train and a screw conveyor, which revolves in a rotating-oscillating manner in a screw flight of the stator, wherein the power train provides the screw conveyor with its drive torque and the power train adapts the differences of the motion sequences of the screw conveyor and of the pump drive shaft. There is thereby an air gap between the motor drive shaft and the pump drive shaft, wherein the motor drive shaft supports a motor-side coupling half and the pump drive shaft supports a pump-side coupling half, which are connected to one another in a torque-transmitting manner by means of magnetic forces across the air gap, wherein the air gap is penetrated by a seal, which hermetically separates the motor region from the rest of the eccentric screw pump.

Claims

1. An eccentric screw pump with a rotor of a pump drive shaft circling essentially about a fixed axis relative to a stator in a bearing block, which pump drive shaft is rotationally driven by motor drive shaft of a motor, a power train and a screw conveyor, which revolves in a rotating-oscillating manner in a screw flight of the stator, wherein the power train provides the screw conveyor with its drive torque and the power train adapts the differences of the motion sequences of the screw conveyor and of the pump drive shaft, characterized in that there is an air gap between the motor drive shaft and the pump drive shaft and that the motor drive shaft supports a motor-side coupling half and the pump drive shaft supports a pump-side coupling half, which are connected to one another in a torque-transmitting manner by means of magnetic forces across the air gap, wherein the air gap is penetrated by a seal, which hermetically separates the motor region from the rest of the eccentric screw pump.

2. The eccentric screw pump according to claim 1, characterized in that the seal is embodied as preferably cylindrical air separating can, which is held on the bearing block with its open side and which forms a cavity, which protrudes beyond the bearing block and which receives the pump-side coupling half.

3. The eccentric screw pump according to claim 1, characterized in that the motor-side and the pump-side coupling half are designed such and are equipped magnetically in such a way that they revolve synchronously with one another in the interference-free operation of the eccentric screw pump.

4. The eccentric screw pump according to claim 3, characterized in that the eccentric screw pump comprises a thermal sensor or another slip detector, which triggers an alarm and/or takes slip-ending measures, as soon as slip occurs between the coupling halves.

5. The eccentric screw pump according to claim 1, characterized in that the pump-side coupling half is cooled by the fluid pumped by the eccentric screw pump.

6. The eccentric screw pump according to claim 5, characterized in that the pump drive shaft supports a pump means, preferably on its front end region facing away from the screw conveyor, preferably a pump wheel, ideally a centrifugal pump wheel, which drives a flow through the air gap.

7. The eccentric screw pump according to claim 5, characterized in that the pump drive shaft is supported on rolling bearings.

8. The eccentric screw pump according to claim 5, characterized in that a continuous, tubularly closed cooling duct is provided, which reaches from the high pressure region all the way into a region of the two coupling halves of the magnetic coupling with lower pressure, so that the higher pressure drives a flow of the pumped fluid from the high pressure region into the region of the magnetic coupling.

9. The eccentric screw pump according to claim 1, characterized in that the bearing block or drive region, respectively, has at least one connection, via which an auxiliary fluid can be introduced, and preferably at least one further connection, via which the auxiliary fluid can be discharged again.

10. The eccentric screw pump according to claim 9, characterized in that the region of the bearing block guiding auxiliary fluid is separated from the region guiding fluid to be pumped by means of a contact seal.

11. The eccentric screw pump according to claim 9, characterized in that the auxiliary fluid is supplied to the bearing block or drive region, respectively, and/or is guided in it so that the bearing block or the drive region, respectively, can be cleaned without disassembly.

12. The eccentric screw pump preferably but not only, according to claim 1, with a screw conveyor, which is rotationally driven by a motor drive shaft of a motor and thereby revolves in a rotating-oscillating manner in a screw flight of the stator, characterized in that the screw conveyor is connected directly to a pump-side coupling half and cooperates with a motor-side coupling half, wherein the two coupling halves are connected to one another in a torque-transmitting manner by means of magnetic forces across an air gap permanently separating them, and the air gap is formed and dimensioned so that it tolerates the rotating-oscillating movement, which the screw conveyor impresses upon the pump-side coupling half.

13. The eccentric screw pump according to claim 12, characterized in that the air gap is penetrated by a seal, which hermetically separates the motor region from the rest of the eccentric screw pump.

14. The eccentric screw pump according to claim 12, characterized in that the eccentric screw pump has characterizing features in that the seal is embodied as preferably cylindrical air separating can, which is held on the bearing block with its open side and which forms a cavity, which protrudes beyond the bearing block and which receives the pump-side coupling half.

15. The eccentric screw pump according to claim 2, characterized in that the motor-side and the pump-side coupling half are designed such and are equipped magnetically in such a way that they revolve synchronously with one another in the interference-free operation of the eccentric screw pump.

16. The eccentric screw pump according to claim 2, characterized in that the pump-side coupling half is cooled by the fluid pumped by the eccentric screw pump.

17. The eccentric screw pump according to claim 2, characterized in that the bearing block or drive region, respectively, has at least one connection, via which an auxiliary fluid can be introduced, and preferably at least one further connection, via which the auxiliary fluid can be discharged again.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The invention will be described on the basis of the following drawings:

[0044] FIG. 1 shows an illustration of an eccentric screw pump;

[0045] FIG. 2 shows a cutout of the eccentric screw pump from FIG. 1;

[0046] FIG. 3 shows a cross section of a further embodiment according to the invention of an eccentric screw pump;

[0047] FIG. 4 shows a cutout of a further embodiment according to the invention in cross section.

DETAILED DESCRIPTION

[0048] FIG. 1 shows an illustration of an eccentric screw pump 1 with a rotor 2 of a pump drive shaft 5 circling essentially about a fixed axis relative to a stator 3 in a bearing block 4. It is rotationally driven by a motor drive shaft 6 of a motor 7. It is connected via a power train 8 to a screw conveyor 9, which revolves in a rotating-oscillating manner in a screw flight 10 of the stator 3.

[0049] The power train 8 thereby provides the screw conveyor 9 with its drive torque. Said power train has the function of adjusting the differences of the motion sequences of the screw conveyor 9 and of the pump drive shaft 5.

[0050] There is a gap referred to as air gap 11 between the motor drive shaft 6 and the pump drive shaft 5. The motor drive shaft 6 thereby supports a motor-side coupling half 12 and the pump drive shaft 5 supports a pump-side coupling half 13, which are connected to one another in a torque-transmitting manner by means of magnetic forces across the air gap 11. Said gap referred to ais air gap 11 is penetrated by a seal 14, which separates the motor region 15 of the motor 7 from the rest of the eccentric screw pump 1.

[0051] The seal 14 is embodied as a cylindrical air separating can, which is held on the bearing block with its open side. It forms a cavity, which protrudes beyond the bearing block and which receives the pump-side coupling half 13. The air separating can thus enlarges the installation space, which the bearing block forms.

[0052] The motor-side coupling half 12 and the pump-side coupling half 13 are designed and magnetically equipped so that they revolve synchronously with one another in the interference-free operation of the eccentric screw pump 1.

[0053] A thermal sensor 16 or another slip detector is provided in order to detect a slip between the two coupling halves 12 and 13. If such a slip occurs, an alarm could be triggered and/or slip-ending measures could additionally be initiated.

[0054] The eccentric screw pump 1 has a continuous, tubularly closed cooling duct 17, which reaches from a first region 18 with high pressure all the way into a second region 19 of the magnetic coupling with lower pressure, so that the higher pressure drives a flow of the pumped fluid from the first region with high pressure into the second region of the magnetic coupling with lower pressure. A cooling flow and/or cleaning flow is created thereby. The cooling duct 17 is illustrated by means of a dashed line.

[0055] FIG. 2 shows a cutout of the eccentric screw pump 1 from FIG. 1, furthermore comprising a centrifugal pump wheel 20, which serves as pump means and drives a flow of the pumped fluid through the air gap 11. The pump-side coupling half 13 can thereby be cooled by means of the pumped fluid.

[0056] The pump drive shaft 5 is preferably supported on a first rolling bearing 21 and a second rolling bearing 22, wherein the rolling bearings 21 and 22 can be embodied as ceramic bearings, so that the service life is extended and the maintenance effort compared to metallic bearings is reduced.

[0057] In a drive region 23 there is arranged a first connection 24, via which an auxiliary fluid can be introduced and there is arranged a second connection 25, via which the auxiliary fluid can be discharged again in order to carry out a cleaning process. The drive region can be cleaned without disassembly thereby.

[0058] The two connections 24 and 25 can also be used in order to intake the pumped fluid within the drive region in order to build up an additional cooling flow.

[0059] FIG. 3 shows a cross section of a further embodiment according to the invention of an eccentric screw pump 1 with a screw conveyor 9, which is rotationally driven by a motor drive shaft 6 of a motor, and thereby revolves in a rotating-oscillating manner in a screw flight 10 of the stator 3.

[0060] The screw conveyor 9 is thereby connected directly, without a power train or another, e.g., cardanically-acting intermediate member, which thus ensures kinematic adjustment, to a pump-side coupling half 13. The latter cooperates with a motor-side coupling half 12.

[0061] In light of the foregoing, the two coupling halves 12 and 13 are connected to one another in a torque-transmitting manner by means of magnetic forces across an air gap 11 separating them permanently (according to the above definition). The air gap 11 is thereby formed and dimensioned so that it tolerates the rotating-oscillating movement, which the screw conveyor 9 impresses upon the pump-side coupling half 13. The eccentricity of the rotating-oscillating movement is therefore smaller than the width of the air gap 11, so that a local dropping of the air gap to zero does not occur.

[0062] The air gap is preferably penetrated by a seal 14 in the form of a cylindrical air separating can. The motor region is then hermetically separated from the rest of the eccentric screw pump 1.

[0063] FIG. 4 additionally shows a cutout of a further embodiment according to the invention in cross section, wherein a preferred arrangement of the individual parts can be seen here in the cross section of all parts.