Magnetic-Coupled Eccentric Screw Pump for Hermetic Fluid Sealing
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Solution Overview
Problem
Existing eccentric screw pumps are unable to safely pump critical, toxic, or environmentally harmful fluids without risking contamination or emissions due to mechanical seal leakage and wear.
Innovation Solution
An eccentric screw pump design featuring a rotor with a pump drive shaft rotating around a fixed axis, using a magnetic coupling with an air gap sealed by a non-ferromagnetic medium to transmit torque without physical contact, and incorporating a cooling and flushing system to prevent contamination and extend service life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a mechanical seal is used to seal the motor area, then the seal provides a physical barrier, but it exhibits leakage and wear especially with critical substances
Solution Approach 1:
The patent replaces the mechanical seal with a magnetic coupling system. The motor drive shaft and pump drive shaft are connected magnetically across an air gap without physical contact, eliminating the mechanical seal that causes leakage and wear. The magnetic coupling transmits torque through magnetic fields while maintaining hermetic separation of the motor area from the pumped fluid.
2Reliability
If the air gap is made larger to prevent contact between coupling halves and seal, then frictional forces and wear are reduced, but the magnetic coupling efficiency decreases
Solution Approach 1:
The patent optimizes the air gap dimensions to a specific range that balances wear prevention and magnetic coupling efficiency. The air gap is sized large enough to prevent contact between the coupling halves and seal under vibration or shock, but small enough to maintain effective magnetic force transmission for torque transfer.
3Reliability
If a seal penetrates the air gap to hermetically seal the motor area, then fluid contamination is prevented, but the magnetic force transmission is impeded
Solution Approach 1:
The patent specifies that the seal must contain no or essentially no ferromagnetic material in the region where magnetic forces act. This local material selection allows the seal to maintain hermetic separation while being transparent to magnetic field penetration, enabling both contamination prevention and effective torque transmission.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables safe pumping of toxic fluids by preventing mechanical wear and leakage, maintaining a hermetic seal, and extending maintenance intervals through a non-contact magnetic coupling and integrated cooling system.
Implementation Method 1
The motor drive shaft carries a motor-side coupling half and the pump drive shaft carries a pump-side coupling half, which are connected to each other across the air gap by means of magnetic forces in a torque-transmitting manner
Data Source
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AI summary
The invention relates to an eccentric screw pump (1) with a rotor (2) consisting of a pump drive shaft (5) rotating substantially around a fixed axis relative to a stator (3) in a bearing seat (4), which is driven in a rotating manner by a motor drive shaft (6) of a motor (7), a power train (8) and a conveying screw (9) which rotates and oscillates in a screw thread (10) of the stator (3), wherein the conveying screw (9) receives its drive torque via the power train (8) and the power train (8) compensates for the differences in the movement sequences of the conveying screw (9) and the pump drive shaft (5).Between the motor drive shaft (6) and the pump drive shaft (5) there is an air gap (11), wherein the motor drive shaft (6) carries a motor-side coupling half (12) and the pump drive shaft (5) carries a pump-side coupling half (13), which are connected to each other by means of magnetic forces across the air gap (11) in a torque-transmitting manner, wherein the air gap (11) is penetrated by a seal (14) which hermetically separates the motor area (15) from the rest of the progressive cavity pump (1).