Prefabricated Yankee Cylinder Sections for External Narrow-Gap Welding
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Solution Overview
Problem
The manufacturing of large-diameter Yankee cylinders is challenging due to stringent requirements for inner pressure resistance, leak-tightness, and large diameter, with conventional methods being time-consuming, costly, and prone to weld imperfections, especially when performed in hot, confined spaces.
Innovation Solution
A Yankee cylinder section workpiece design featuring welding bevels and reinforcement flanges allows for narrow gap welding from the outside, reducing the need for internal welding and minimizing heat deformation, with prefabricated grooves machined to final dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional welding method (TIG from inside, GSMA from outside) is used to manufacture Yankee cylinder sections, then the cylinder sections can be joined together, but the manufacturing process becomes time-consuming and costly with high risk of weld imperfections
Solution Approach 1:
The invention applies preliminary action by pre-fabricating grooves on the inner surface of the cylinder shell before welding. These grooves are created in advance to guide the welding process and ensure proper weld penetration and quality, eliminating the need for time-consuming post-weld machining and reducing the risk of weld imperfections.
Solution Approach 2:
The invention inverts the conventional welding approach by performing welding from the outside (GSMA method) only, without requiring internal TIG welding. The pre-fabricated grooves on the inner surface guide the external welding process to achieve proper weld quality, thereby eliminating the need for operators to work in confined hot spaces inside the cylinder and significantly reducing manufacturing time.
2Reliability
If operators perform TIG welding from inside the cylinder, then weld joints can be formed, but operators work under hard conditions of hot, confined spaces
Solution Approach 1:
The invention inverts the welding direction by performing all welding operations from the outside of the cylinder shell using the GSMA method. Pre-fabricated grooves on the inner surface guide the external welding process to ensure proper weld penetration and joint formation, completely eliminating the need for operators to work in confined hot spaces inside the cylinder and significantly improving operator working conditions.
3Manufacturing precision
If multiple welding and machining steps are performed to create inner grooves and achieve final dimensions, then the Yankee cylinder meets specification requirements, but the process becomes time and cost intense
Solution Approach 1:
The invention applies preliminary action by pre-fabricating grooves on the inner surface of the cylinder shell before welding. These grooves are created in advance with precise dimensions to match the final specification requirements, eliminating the need for time-consuming post-weld machining operations and significantly reducing manufacturing cycle time while maintaining manufacturing precision.
Solution Approach 2:
The invention segments the manufacturing process by separating the groove fabrication from the welding process. Grooves are pre-fabricated on the inner surface before welding operations, allowing independent optimization of each process and eliminating the need for sequential welding followed by machining, thereby reducing overall manufacturing time while maintaining precision.
4Strength
If conventional welding procedures are used with multiple passes and finishing operations, then weld strength is achieved, but material and energy consumption increase
Solution Approach 1:
The invention applies preliminary action by pre-fabricating grooves with optimized geometry before welding. These pre-formed grooves are designed to guide the welding process and ensure proper penetration in a single or minimal number of welding passes, eliminating the need for multiple welding passes and subsequent machining operations, thereby reducing energy consumption while maintaining weld strength.
Data Source
Figure 1~2
Figure 3
AI summary
A prefabricated Yankee cylinder section and a manufacturing method for a Yankee cylinder. The manufacturing method comprises: performing welding to internally connect first reinforcement flanges (101, 201) of two prefabricated Yankee cylinder sections (1, 2); performing preheating, and performing welding outside a housing to connect the two prefabricated Yankee cylinder sections (1, 2); performing machining to remove the first reinforcement flanges (101, 201) and second reinforcement flanges (102, 202) of the prefabricated Yankee cylinder sections and materials at and surrounding a radial inner end portion of a weld seam until regions at connections between the two prefabricated Yankee cylinder sections (1, 2) have been processed to meet the final size requirement of an internal cavity of a Yankee cylinder.