Syringe Assembler Stopper Movement Detection
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Solution Overview
Problem
Conventional monitoring systems for attaching plunger rods to syringe stoppers in pre-filled syringes fail to accurately detect movement of the stopper relative to the syringe barrel, potentially leading to contamination of the liquid dosage, as they only assess movement after plunger rod attachment and do not account for barrel movement or temporary displacements during the attachment process.
Innovation Solution
A method and system that utilize a pair of cameras to take digital images before, during, and after plunger rod insertion and attachment, comparing these images using a computer processor to determine if the stopper has moved relative to the syringe barrel, ensuring proper attachment and sterility by capturing initial and subsequent positions simultaneously and accounting for barrel rotation and temporary displacements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional monitoring systems take digital images before and after plunger rod attachment to detect stopper movement, then the system can identify potential contamination, but the system fails to accurately detect stopper movement relative to the syringe barrel due to barrel movement between images
Solution Approach 1:
The patent introduces a stationary reference object (such as a marker or feature on the syringe barrel) as an intermediary between the stopper and the imaging system. By capturing images of both the stopper and the reference object simultaneously, the system can calculate stopper movement relative to the barrel by comparing their positions, eliminating errors from barrel movement between images.
Solution Approach 2:
The system establishes a reference frame by capturing an initial image pair showing both the stopper and the stationary reference object at the beginning of the attachment process. This preliminary reference is then used to evaluate stopper movement throughout the entire attachment sequence, allowing detection of any deviation from the initial position relative to the barrel.
2Device complexity
If conventional systems only check stopper position after plunger rod attachment is complete, then the process is simple, but temporary stopper displacements during attachment that return to original position are not detected
Solution Approach 1:
The monitoring system continuously captures images at multiple time points throughout the entire plunger rod attachment process, not just at the beginning and end. This continuous monitoring ensures that any temporary stopper displacement, even if it returns to the original position, is detected and recorded, maintaining sterility assurance without excessive complexity.
3Measurement precision
If the system takes multiple pairs of digital images during the attachment process, then accurate stopper movement relative to the barrel can be detected, but the complexity and time required for monitoring increases
Solution Approach 1:
The system takes digital image pairs at periodic intervals during the attachment process rather than continuously. Key capture moments include the initial state, intermediate stages, and final state. This periodic sampling provides sufficient data to detect stopper movement while minimizing the time added to the attachment process.
Data Source
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AI summary
A method for assembling a syringe includes supporting a syringe barrel having a stopper being movably disposed therein. A distal end of a plunger rod is inserted into the compartment of the syringe barrel. An initial digital image is taken of the stopper within the syringe barrel. The distal end of the plunger rod is coupled to the stopper located within the syringe barrel so that the plunger rod is secured to the stopper. A plurality of further digital images of the stopper within the syringe barrel are taken during or after coupling the distal end of the plunger rod to the stopper. Information determined from each of the further digital images is compared to information determined from the initial digital image using a computer processor to determine if the stopper in each of the further digital images has moved relative to the syringe barrel.