Screw Pump Cleaning Control for Deposit-Buildup Reliability
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Solution Overview
Problem
Screw pumps used in vacuum applications with contaminated gases face operational reliability issues due to deposits that accumulate on the screw surfaces, narrowing the tolerance range for rotational positions and potentially leading to pump failure.
Innovation Solution
A method involving controlled variation of the relative rotational position of the screws within a tolerance range to abrade deposits without mechanical contact, using a control unit to synchronize and adjust the screws' positions, combined with a cleaning mode to remove deposits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the screw pump operates with synchronous rotation to maintain contactless operation, then the operational reliability is improved, but deposits accumulate on screw surfaces narrowing the tolerance range
Solution Approach 1:
The patent applies periodic action by introducing a cleaning mode that periodically varies the relative rotational position of the screws within the tolerance range. This periodic variation causes deposits to be abraded between screw surfaces without mechanical contact, preventing deposit accumulation while maintaining contactless operation during normal pumping cycles
Solution Approach 2:
The patent applies dynamics by transitioning from a static relative rotational position (fixed in the middle of tolerance range) to a dynamic position that can be systematically varied within the tolerance range. This dynamic adjustment allows the system to adapt between normal operation mode and cleaning mode, preventing deposit buildup while maintaining operational reliability
2Reliability
If the relative rotational position is varied to remove deposits, then the tolerance range is maintained, but synchronization complexity increases
Solution Approach 1:
The patent applies parameter changes by systematically varying the relative rotational position parameter within the existing tolerance range. This controlled parameter variation enables deposit removal through abrasion while maintaining contactless operation, improving restart capability without requiring fundamental changes to the pump structure
Solution Approach 2:
The patent applies feedback through a control unit that monitors and adjusts the rotational positions of both screws to maintain proper synchronization. The control unit receives input from rotational angle sensors and automatically adjusts the screws' positions, managing the synchronization complexity through automated feedback control rather than mechanical coupling alone
3Reliability
If deposits accumulate on screw surfaces, then the tolerance gap narrows, but mechanical contact is avoided during normal operation
Solution Approach 1:
The patent converts the harmful effect of deposit accumulation into a beneficial cleaning mechanism. By deliberately varying the relative rotational position within the tolerance range, deposits that would normally accumulate and narrow the tolerance gap are instead caused to contact and abrade against each other, effectively self-cleaning the screw surfaces without mechanical contact between the screw substrates
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
Enhances operational reliability by preventing pump failure through effective removal of deposits, allowing for easy restart after inactivity and maintaining efficient operation.
Implementation Method 1
Deposits within this tolerance gap come into contact with each other and are abraded without any mechanical contact between the substrate of the first screw pump and the substrate of the second screw pump
Data Source
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AI summary
A method for operating a screw pump (14), wherein the screw pump (14) comprises a first screw (31) and a second screw (32). A thread of the first screw (31) engages with a thread of the second screw (32), such that the mutual engagement of the threads forms working chambers whose volume decreases from a suction side (20) of the screw pump (14) to a pressure side (21) of the screw pump (14). The screws (31, 32) are set into non-contact rotation. Within a tolerance range (25) of the non-contact rotation, the relative rotational position of the first screw (31) and the second screw (32) is intentionally changed in order to remove a deposit from a surface of the first screw (31) and a surface of the second screw (32). The invention also relates to a control unit for a screw pump, a screw pump, and a computer program.