Composite Pipe Press Fitting Nipple to Prevent Metallic Layer Folds
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Solution Overview
Problem
Existing connection techniques for multi-layer composite pipes with a metallic inner layer, such as stainless steel, fail to provide a secure and tight press fit due to the formation of axial folds and potential damage from sharp edges, leading to leaks and instability.
Innovation Solution
A connection nipple with a profiled cylindrical base body and cylindrical jacket sections on both sides of the sealing ring groove, featuring a circular pipe receiving groove with a width greater than the sealing ring groove, ensures a deformation-free press fit and gap seal, preventing folds and ensuring a firm connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional press fittings are used with composite pipes having a metallic inner layer, then the pipe can be connected to the fitting, but axial folds form in the metallic inner layer during compression, creating open channels that prevent tight sealing
Solution Approach 1:
The connection nipple features a cylindrical jacket section with specific dimensional characteristics (width and depth) that creates a localized deformation-free zone. This section has a different geometric quality compared to the rest of the nipple, specifically designed to accommodate the metallic inner layer without causing radial compression that would lead to fold formation.
Solution Approach 2:
The connection nipple is segmented into distinct functional zones: a cylindrical jacket section that prevents fold formation, a sealing ring groove area for tight sealing, and a pipe receiving groove for mechanical anchoring. This segmentation allows each zone to perform its specific function without interfering with the others.
2Stability of the object's composition
If the connection nipple has a tight fit with the composite pipe, then connection stability is improved, but the metallic inner layer is more prone to folding and damage during compression
Solution Approach 1:
The cylindrical jacket section provides a localized region with optimized dimensional characteristics that accommodates the metallic inner layer during compression. The specific width and depth of this section create a deformation-free zone that prevents fold formation while maintaining overall connection stability through the integrated sealing and anchoring mechanisms.
3Strength
If sharp-edged profiles are used in the connection nipple, then mechanical anchoring of the pipe is improved, but the thin metallic inner layer is punctured or damaged
Solution Approach 1:
The connection nipple incorporates a cylindrical jacket section with rounded, fold-free characteristics that provides a transition zone between the pipe and the profiled anchoring sections. This local geometric modification prevents stress concentration and sharp edge contact with the metallic inner layer, thereby preventing puncture damage while maintaining mechanical anchoring strength through the integrated pipe receiving groove.
Data Source
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AI summary
A device for connecting a composite pipe (1) with a metallic inner layer (2) to a connection nipple (4) of a press fitting (5) is described, the connection nipple having a profiled shape that accommodates at least one sealing ring (6) in a sealing ring groove (7) of the connection nipple. To create advantageous connection conditions, it is proposed that the connection nipple (4) has a profiled cylindrical base body (8), wherein, viewed in the axial direction of the connection nipple (4), a cylindrical shell section (9) of the base body (8) adjoins it on both sides of the sealing ring groove (7) with the sealing ring (6), and is bounded on at least one side facing away from the sealing ring groove (7) by a pipe receiving groove (10).