Metered Liquid Administration Device Axial Play Reduction
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Solution Overview
Problem
Existing devices for metered administration of liquid products, such as infusion and injection appliances, face challenges in achieving accurate dosing due to axial play between the delivery mechanism and the housing, which affects metering precision and occlusion detection.
Innovation Solution
A device with a force sensor and contact element that reduces axial play between the delivery mechanism and the housing by adjusting into a secure position, using a threaded engagement to eliminate or minimize play, and ensuring thermal expansion matching between components to maintain precision and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the delivery means is supported on the housing via a sensor to enable occlusion detection, then occlusion detection capability is improved, but axial play between the delivery mechanism and housing increases which deteriorates metering precision
Solution Approach 1:
A support structure is introduced as an intermediary element between the delivery means and the housing. This support structure provides mechanical support to eliminate axial play while allowing the sensor to maintain its detection function. The support structure acts as a mediator that resolves the conflict between needing mechanical stability for precision and needing sensor support for occlusion detection.
2Measurement precision
If the delivery means is rigidly fixed to the housing to eliminate axial play, then metering precision is improved, but occlusion detection capability deteriorates due to loss of sensor support function
Solution Approach 1:
The support system is segmented into separate functional elements: a support structure for mechanical stability and a sensor for occlusion detection. This segmentation allows each element to perform its specific function independently - the support structure eliminates axial play while the sensor maintains its ability to detect occlusions by supporting the delivery means.
3Ease of manufacture
If different materials are used for the housing and delivery means, then manufacturing ease and cost are improved, but thermal expansion discrepancies increase which deteriorates metering accuracy
Solution Approach 1:
The patent addresses thermal expansion discrepancies by controlling material selection and design parameters. By carefully selecting materials with compatible thermal expansion coefficients or by designing the support structure to compensate for differential thermal expansion, the patent maintains metering accuracy while allowing the use of different materials for manufacturing ease.
Data Source
AI summary
A device for administering doses of a substance, the device including a housing forming one of a product reservoir or a receiving seat for a product reservoir, a force sensor, a delivery mechanism which executes an axial output movement in a delivery direction to deliver a dose from the product reservoir, and which is supported via the sensor on the housing counter to the delivery direction, and a contact element on which the sensor is axially supported, at least one of the contact element and sensor forming a device for reducing play which, in an adjustment engagement with at least one of the housing or the delivery mechanism, is displaced into an adjustment position and axially secured in the adjustment position in such a way that axial play between the delivery mechanism and the housing is reduced.