Rotatable Plunger Repositioning Tool for Pump Maintenance
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Solution Overview
Problem
Existing plunger repositioning systems in pumps face challenges in securely locking and unlocking the plunger to facilitate maintenance, particularly in accessing the stuffing box for seal replacement, due to complex threaded connections and limited visibility during the repositioning process.
Innovation Solution
A tool with concentric and rotatable shafts and coaxial head elements, where the inner and outer shafts are rotated to align and skew their cross-sectional profiles, locking the plunger in place, allowing for secure withdrawal and repositioning without visual confirmation, utilizing a mechanism to resist relative rotation and ensure accurate positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a threaded connection is used to connect the plunger to the rod, then the connection strength is improved, but the complexity of disassembly and repositioning increases
Solution Approach 1:
The tool divides the locking function into two separate head elements (forward and rear) that can independently engage with the plunger at different locations. This segmentation allows the tool to maintain strong connection through multiple engagement points while enabling easier disassembly by simply rotating the shafts to disengage the profiles.
Solution Approach 2:
The locking mechanism uses rotatable shafts with cross-sectional profiles that can dynamically transition between engaged and disengaged states. By rotating the inner or outer shaft, the cross-sectional profiles align to lock the plunger or misalign to unlock it, providing both strong connection and ease of repositioning.
2Reliability
If a locking mechanism is added to secure the plunger, then the reliability of plunger holding is improved, but the device complexity increases
Solution Approach 1:
The tool combines the locking and unlocking functions into a single integrated mechanism using concentric rotatable shafts with cross-sectional profiles. Both head elements work together through the same rotational motion, merging multiple functions into one simple operation that reduces overall device complexity while maintaining reliability.
Solution Approach 2:
The tool uses nested concentric shafts where the inner shaft is positioned within the outer shaft. Both shafts support head elements that engage the plunger simultaneously, creating a compact nested structure that provides reliable locking without adding excessive complexity to the device architecture.
3Measurement precision
If visual confirmation is required during repositioning, then the precision of plunger positioning is improved, but the time required for maintenance increases
Solution Approach 1:
The locking mechanism is self-indicating through its mechanical design. When the cross-sectional profiles align, the shafts automatically lock into position with audible or tactile feedback, eliminating the need for visual confirmation. The mechanism serves itself by providing inherent positioning feedback through the engagement of the profiles.
Solution Approach 2:
The invention replaces visual confirmation methods with a mechanical self-locking system. The cross-sectional profiles on the rotatable shafts provide inherent mechanical feedback through engagement and disengagement, substituting the need for visual measurement or confirmation with a self-evident mechanical state change.
Data Source
AI summary
A tool for repositioning a plunger is formed from a pair of concentric and relatively rotatable shafts. The inner and tubular outer shafts respectively support enlarged forward and rear head elements. The shafts are relatively rotatable between a first position, in which the cross-sectional profiles of the head elements are aligned, and a second position, in which the cross-sectional profiles of the head elements are in skewed opposition. A ball detent mechanism at the interface between the forward and rear head elements permits accurate location of the first and second positions. The tool is used with a tubular collar element having a stem section and an enlarged flange section, and a disk-shaped platform element having a centrally disposed and internally threaded opening. The threaded opening in the platform element receives the externally threaded outer shaft of the tool.