Sterilizable Pump Unit Using Permeable Valve Closure Members
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Solution Overview
Problem
Existing pump units for medical water jet surgery face challenges in ensuring uniform, non-pulsating delivery of NaCl solution across a wide range of adjustable delivery volumes and in achieving effective sterilization, particularly due to the difficulty of gas sterilization reaching all parts of the unit.
Innovation Solution
A pump unit design featuring a housing composed of two parts with integrated valve chambers and valve closure members made of permeable plastic, allowing low-molecular sterilization gases to penetrate easily, and a simple assembly structure that ensures correct positioning and easy sterilization without the need for high pressure differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gas sterilization methods are used to sterilize the pump unit, then sterilization is achieved, but the sterilization gas cannot effectively reach all relevant points of the pump unit because the pump unit is configured to convey liquids, not gases
Solution Approach 1:
The valve closure members are made from gas-permeable elastomers that allow sterilization gas to penetrate through them. This porous material approach enables the sterilization gas to reach all internal channels and surfaces of the pump unit without requiring complex disassembly or special sterilization procedures, thereby resolving the contradiction between achieving reliable sterilization and maintaining simple device structure
2Reliability
If valve springs or biasing mechanisms are used to ensure valve closure, then sealing is improved, but the surface pressure at the valve seat increases causing the valve closure member to adhere to the valve seat, preventing low flow rate operation
Solution Approach 1:
The patent replaces traditional mechanical valve springs and biasing mechanisms with a valve closure member made from gas-permeable elastomer that relies on material elasticity and gas permeability properties rather than mechanical force. This substitution allows the valve to maintain reliable sealing through the inherent properties of the elastomer material while enabling operation at very low flow rates without adhesion problems, thus resolving the contradiction between valve sealing reliability and productivity across wide flow rate ranges
3Reliability
If the pump unit is designed as a disposable sterile product, then sterilization requirements are met, but the complexity of ensuring complete sterilization penetration increases
Solution Approach 1:
The valve closure members are made from gas-permeable elastomers that allow sterilization gas to penetrate through them. This porous material approach enables the sterilization gas to reach all internal channels and surfaces of the pump unit without requiring complex disassembly or special sterilization procedures, thereby resolving the contradiction between achieving reliable sterilization and maintaining simple device structure
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design achieves reliable sterilization and uniform liquid delivery with minimal pressure requirements, ensuring effective operation across varying flow rates and delivery volumes, while maintaining a simple and robust assembly process.
Implementation Method 1
the valve closure member is permeable to sterilisation gas. It consists for example of a plate or disc made of a suitable plastic, such as silicone or an elastomer... low-molecular sterilisation gases can penetrate through the valve closure member at a sufficient rate
Data Source
AI summary
The pump unit (10) has a particularly simple design, which includes just two housing parts (14, 15) and also four valve closure members (37) and pump pistons (25, 29). The valve closure members (37) are preferably identical to one another and are trapped in a pocket between both housing parts (14, 15). The housing parts (14, 15) are preferably permanently interconnected by an ultrasonic weld seam. The valve closure members are formed by disc-like or plate-like plastic parts, which are resilient per se and which may optionally have a central pin (42) as an assembly and orientation aid. As desired, the valve closure members bear against their respective valve seat (43) with or without bias and form valves which open and close particularly reliably, are responsive to the slowest flow velocities and can be easily sterilized.