Endoscope Check Valve Assembly Backflow Prevention
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Solution Overview
Problem
Existing check valve assemblies for endoscopes, particularly those using elastic valve sleeves, face challenges in manufacturing costs and effective positioning due to specific mold requirements, and commercially available rubber tubes often lack sufficient return force for reliable operation.
Innovation Solution
A check valve assembly with a discharge nozzle unit featuring a large and small diameter portion, an elastic tubular portion, and a valve housing that includes a positioning mechanism and packing portion to securely position the elastic tubular portion, allowing for reliable opening and closing of the valve element to prevent backflow, utilizing a commercially available rubber or elastomer tube.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a specific shaped elastic valve sleeve is used to ensure tight contact and reliable backflow prevention, then the check valve assembly can effectively prevent backflow, but the manufacturing cost increases due to particular mold requirements
Solution Approach 1:
The patent changes the geometric parameters of the discharge nozzle unit by introducing a large diameter portion and a small diameter portion with different diameters. This parameter variation allows a commercially available rubber tube to be positioned correctly without requiring special molding, thus reducing manufacturing cost while maintaining reliable backflow prevention through the elastic tubular portion's return force.
2Ease of manufacture
If a commercially available rubber tube is used to reduce manufacturing cost, then the manufacturing cost decreases, but the return force is too small to exactly position the check valve assembly for the fluid openings
Solution Approach 1:
The patent applies local quality by creating a discharge nozzle unit with different diameter portions (large diameter portion and small diameter portion). The small diameter portion provides the necessary positioning precision for the fluid openings, while the large diameter portion ensures sufficient return force. This local variation in geometry allows a simple rubber tube to achieve both correct positioning and reliable operation.
3Reliability
If the elastic tubular portion is squeezed fixedly between the discharge nozzle unit and valve housing in the axial direction, then the large diameter portion contacts the discharge nozzle unit tightly, but the structure becomes more complex
Solution Approach 1:
The patent merges the positioning function and the sealing function into a single discharge nozzle unit structure with varying diameter portions. The large diameter portion and small diameter portion work together to simultaneously provide tight contact and correct positioning of the elastic tubular portion, eliminating the need for separate positioning mechanisms and reducing overall structural complexity.
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 solution enables a simple and cost-effective check valve assembly that reliably prevents backflow by using a commercially available rubber tube with enhanced return force and precise positioning, ensuring effective fluid control and reduced manufacturing costs.
Implementation Method 1
When the fluid pressure applied to the inside of the elastic valve sleeve decreases, return force of the elastic valve sleeve recovers its original form with the normal diameter. A backflow of the fluid can be prevented by closing of the fluid openings with the elastic valve sleeve.
Data Source
AI summary
A check valve assembly includes a valve housing upstream of an endoscope. A tubular discharge nozzle unit is mounted in the valve housing, and supplied with fluid by a fluid supply source. The discharge nozzle unit includes a large diameter portion, a small diameter portion, formed on the large diameter portion on a distal side, and having a closed distal end nearer to the endoscope, and a fluid opening formed through a wall of the small diameter portion. An elastic tubular portion (sleeve) is contained in the valve housing, disposed around the small and large diameter portions, shaped tubularly with a substantially regular thickness, having an inner diameter which is smaller than an outer diameter of the small diameter portion in a normal state, for preventing the fluid from backflow into the fluid opening through the outer surface on a side downstream of the discharge nozzle unit.