Edge-Welded Bellows Guide Sleeve for Buckling and Weld Wear
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Solution Overview
Problem
Diaphragm bellows experience lateral buckling due to pressure differences and gravitational forces, leading to wear at weld seams and potential leaks, with existing guide solutions either restricting axial travel or increasing dynamic loads.
Innovation Solution
A guide part configuration with a guide sleeve having a wall thickness more than three times that of the retaining fin, featuring a step with a contact surface for securement, and a fastening sleeve for form-fitting retention, allowing stable guidance without welding, and incorporating ventilation openings for effective separation between guide parts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If guide parts are added to prevent lateral buckling, then reliability is improved, but device complexity increases
Solution Approach 1:
The guide part is segmented into two functional components: a guide sleeve for providing guidance and a retaining fin for securing the assembly. This segmentation allows each component to be optimized independently while working together to solve the lateral buckling problem without excessive complexity
Solution Approach 2:
The guide part employs a nested structure where the guide sleeve is positioned over the retaining fin, and the rod passes through the central opening in the retaining fin. This nesting arrangement compactly integrates multiple functions (guidance, retention, and structural support) into a space-efficient configuration that prevents lateral buckling without significantly increasing overall device complexity
2Reliability
If a thick-walled guide sleeve is used for stable guidance, then reliability is improved, but manufacturing complexity increases
Solution Approach 1:
The guide sleeve exhibits local quality variation with its thick-walled configuration, concentrating material where structural stability and guidance precision are most needed. This localized thick-walled design provides the necessary rigidity for stable guidance while avoiding unnecessary material usage in less critical areas, balancing manufacturing feasibility with performance requirements
3Duration of action of stationary object
If guide parts are added to prevent lateral buckling, then durability is improved, but axial travel is restricted
Solution Approach 1:
The guide part acts as an intermediary element between the rod and the diaphragm bellows, providing guidance and preventing lateral buckling through the guide sleeve and retaining fin structure. This intermediary mechanism protects the weld seams from wear caused by lateral movements while being designed with sufficient clearance and flexibility to allow the required axial travel distance, thus balancing durability improvement with movement freedom
Data Source
AI summary
An edge-welded bellows, including a plurality of diaphragms and a guide part for guiding on the outer surface of a rod extending through an inner through-opening of the bellows or for guiding on the inner surface of a tube surrounding the bellows. The guide part has a retaining fin, which, at the edge thereof, lies between the edges of adjacent diaphragms and is welded thereto, and a guide sleeve, which surrounds the longitudinal central axis and has a guide surface for guiding the bellows on the outer surface of the rod or the inner surface of the tube. The guide sleeve has a wall thickness that is more than three times that of the retaining fin. The guide sleeve has a step having a contact surface. The retaining fin lies, in a region adjoining the edge thereof, on the contact surface and is form-fittingly secured against being lifted off from the contact surface.