Fluid Dispensing Device Piston Seal Offset
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Solution Overview
Problem
Existing fluid dispensing devices, particularly drug pumps, face issues with direct or indirect fluid overflow due to gaps between seals on pistons, leading to uncontrolled fluid transfer and compromised functionality, especially when multiple ports are involved.
Innovation Solution
A fluid dispensing device with a cylinder having at least three openings in series and pistons with offset seals, where the distance between adjacent seals matches the shortest distance between openings, preventing direct overflow and ensuring each opening is sealed, along with a drive system for flexible and reliable fluid delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If seals are placed on pistons to seal off the transition from piston to cylinder inner wall, then sealing effect is improved, but direct or indirect fluid overflow between openings occurs due to gaps between seals
Solution Approach 1:
The patent introduces a radial dimension solution by providing sealing elements that extend radially from the piston surface into the openings. This radial extension creates multiple sealing zones within each opening, preventing fluid overflow in the longitudinal direction while maintaining the gap between seals. The sealing elements project into the openings from the piston, creating a three-dimensional sealing architecture that addresses the overflow problem without requiring the pistons to be in direct longitudinal contact.
2Reliability
If pistons are moved closer together to prevent fluid overflow, then fluid communication control is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent applies local quality by providing sealing elements only at specific locations where openings are present on the pistons. Rather than requiring uniform close spacing of entire pistons, the sealing elements are localized to the opening regions, extending radially to prevent fluid overflow only where needed. This localized approach maintains fluid communication control while avoiding the complexity of overall piston rearrangement.
3Adaptability or versatility
If multiple openings are provided on cylinders for versatile applications, then adaptability is improved, but risk of direct or indirect fluid overflow between openings increases
Solution Approach 1:
The patent segments each opening into separate sealing zones by providing individual sealing elements that extend radially from the piston surface into each opening. This segmentation creates independent sealed compartments for each opening, allowing multiple openings to be provided on the cylinder for versatile applications (such as connecting multiple containers or performing multiple functions) while preventing fluid overflow between them through the radial sealing barriers.
Data Source
Figure 1~3
Figure 4
Figure 5a~6
AI summary
The invention proposes a device (1) and the use thereof for dispensing a fluid, in particular under aseptic conditions. Said device (1) comprises a conveying device (2) and a container (3) with a variable inner volume. The conveying device (2) comprises a cylinder (4) with at least three openings (5, 6, 7) which are arranged in a row along a longitudinal central axis (11) and through which the fluid can be conveyed. The conveying device (2) moreover comprises a first and a second piston (9, 10). The first and the second piston (9, 10) are arranged in the cylinder (4) in such a way as to be displaceable along the longitudinal central axis and, between their end faces (11, 12), they delimit a variable fluid volume (14) together with a portion of the inner wall (13) of the cylinder. The first opening (5) can be brought into fluidic communication with a dispensing opening (15) of the device (1), and the second opening (6) can be brought into fluidic communication with the container (3). The first and the second piston (9, 10) each comprise at least three seals (16, 16', 16'') which are offset in the longitudinal direction and which close off the cylinder (4) sealingly. Adjacent seals (16, 16' or 16', 16'') on a piston (9, 10) have an inner spacing di which is at most equal to the shortest spacing aA1 between two adjacent openings (5, 6 or 6, 7).