Eccentric Screw Pump Jamming Rectification via Reversing Motor Control
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Solution Overview
Problem
Conveying apparatuses with eccentric screw pumps for viscous construction materials face challenges in detecting and rectifying rotor/stator unit jamming during startup, leading to inefficient operation and prolonged downtime.
Innovation Solution
A fault-rectification method involving a control device that monitors characteristic variables such as rotational speed, current consumption, and pressure to identify jamming, automatically switching the electric motor on and off in alternating directions, and restarting the conveying operation once jamming is cleared, while ensuring the pump is not overloaded.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the conveying apparatus operates continuously without jamming detection, then productivity is maintained, but the rotor/stator unit may become jammed leading to downtime and damage
Solution Approach 1:
The control device monitors characteristic variables (current consumption, rotational speed, pressure) before complete jamming occurs, enabling early detection and intervention. This preliminary monitoring prevents full jamming while maintaining operational continuity
Solution Approach 2:
The system continuously monitors characteristic variables and provides feedback to the control device, which automatically adjusts operation or triggers alarms. This closed-loop feedback enables reliable jamming detection without requiring complex manual inspection systems
2Reliability
If the pump is switched off frequently to prevent jamming, then the rotor/stator unit is protected from damage, but productivity decreases due to operational interruptions
Solution Approach 1:
The control device dynamically adjusts the operational state based on real-time monitoring of characteristic variables. Instead of fixed switching schedules, the system adapts operation continuously, switching off only when necessary based on actual jamming risk indicators
Solution Approach 2:
The system monitors changes in characteristic variables (current consumption patterns, rotational speed variations, pressure changes) to detect jamming conditions. By tracking parameter changes rather than using fixed thresholds, the system maintains productivity while protecting the rotor/stator unit
3Ease of operation
If manual jamming detection and rectification is used, then the system is simpler, but operation time is prolonged and downtime increases
Solution Approach 1:
The control device automatically detects jamming conditions through monitoring characteristic variables and initiates rectification actions without requiring manual intervention. The system serves itself by identifying and responding to jamming conditions, eliminating the need for operator involvement in detection and initial rectification
Solution Approach 2:
The system rapidly detects and responds to jamming conditions by monitoring multiple characteristic variables simultaneously and executing automatic rectification procedures. This rushed response through automated detection and action minimizes the time lost to jamming events compared to manual detection and response
4Productivity
If the electric motor is overloaded to clear stubborn jamming, then the jamming is released faster, but the rotor/stator unit and motor are damaged
Solution Approach 1:
The control device applies partial excessive action by temporarily increasing motor power only to the extent necessary to clear the jamming, based on monitored characteristic variables. This controlled excessive action clears jams faster than gradual application while remaining below damage thresholds through continuous monitoring
Solution Approach 2:
The system provides beforehand cushioning by monitoring characteristic variables that indicate approaching jamming conditions and taking preventive action before complete jamming occurs. This prior cushioning through early detection and gradual response prevents the need for forceful jamming clearance that could damage components
Data Source
AI summary
A fault-rectification method for an eccentric screw pump of a conveying apparatus for conveying viscous construction materials, comprising the steps of monitoring a start of a conveying operation of the eccentric screw pump by way of a characteristic-variable-monitoring program of a control device of the conveying apparatus, wherein a working-free program is executed by the control device of the eccentric screw pump if, for one or more characteristic variables. The characteristic-variable-monitoring program acquires characteristic-variable values which are stored, alone or in combination with one another, as fault values that indicate jamming of a rotor/stator unit of the eccentric screw pump, and wherein otherwise a conveying operation is begun. The eccentric screw pump is operated in the working-free program in such a way that an electric motor of a drive unit of the conveying apparatus is multiply alternately switched on and switched off.