Eccentric screw pump with magnetic coupling
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.
1 . An eccentric screw pump comprising:
a rotor of a pump drive shaft circling about a fixed axis relative to a stator in a bearing block, the pump drive shaft being 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 drive torque, and the power train adjusts differences of motion sequences of the screw conveyor and of the pump drive shaft,
wherein the eccentric screw pump includes 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, and wherein the air gap is penetrated by a seal, which hermetically separates a motor region from the rest of the eccentric screw pump, and
wherein the bearing block or drive region has at least one connection configured to introduce an auxiliary fluid, and at least one further connection configured to discharge the auxiliary fluid.
2 . The eccentric screw pump according to claim 1 , wherein the seal is embodied as a cylindrical air separating can, wherein the cylindrical air separating can has an open side that is held on the bearing block, and wherein the cylindrical air separating can 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 2 , wherein the motor-side coupling half and the pump-side coupling half are designed and are equipped magnetically in such a way that they revolve synchronously with one another in an interference-free operation of the eccentric screw pump.
4 . The eccentric screw pump according to claim 2 , wherein the pump-side coupling half is cooled by a fluid pumped by the eccentric screw pump.
5 . The eccentric screw pump according to claim 1 , wherein the motor-side coupling half and the pump-side coupling half are designed and are equipped magnetically in such a way that they revolve synchronously with one another in an interference-free operation of the eccentric screw pump.
6 . The eccentric screw pump according to claim 5 , further comprising a thermal sensor or a slip detector, which triggers an alarm and/or takes slip-ending measures, as soon as slip occurs between the coupling halves.
7 . The eccentric screw pump according to claim 1 , wherein the pump-side coupling half is cooled by a fluid pumped by the eccentric screw pump.
8 . The eccentric screw pump according to claim 7 , wherein the pump drive shaft supports a pump means, which drives a flow through the air gap.
9 . The eccentric screw pump according to claim 8 , characterized in that the pump drive shaft supports the pump means on a front end region of the pump drive shaft facing away from the screw conveyor.
10 . The eccentric screw pump according to claim 9 , wherein the pump means is a centrifugal pump wheel.
11 . The eccentric screw pump according to claim 7 , wherein the pump drive shaft is supported on rolling bearings.
12 . The eccentric screw pump according to claim 7 , further comprising a continuous, tubularly closed cooling duct, which reaches from a high pressure region all the way into a region of a 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, wherein the region of the magnetic coupling is arranged at the coupling halves.
13 . The eccentric screw pump according to claim 1 , wherein a region of the bearing block guiding the auxiliary fluid is separated from a region guiding fluid to be pumped via a contact seal.
14 . The eccentric screw pump according to claim 1 , wherein the auxiliary fluid is supplied to the bearing block or the drive region and/or is guided in the bearing block or the drive region, so as to be cleaned without disassembly.