Additive-Manufactured Stuffing Box Cooling for Leak-Safe Sealing
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Solution Overview
Problem
Traditional stuffing boxes for reciprocally movable piston rods in compressors and rotating machinery face challenges with sliding friction, heat generation, and complex machining processes, which limit cooling circuit optimization and lead to potential leakage issues.
Innovation Solution
A packing box with a coolant circulation structure created through additive manufacturing, featuring a single or multiple conduits wound around the central opening to form a cooling circuit, eliminating the need for additional plugs and allowing for optimized cooling and lubrication circuit designs with arbitrary geometries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional machining processes are used to create cooling circuits in packing boxes, then the cooling circuits can be formed, but the manufacturing process becomes complex and delicate with potential leakage issues
Solution Approach 1:
The patent merges the cooling circuit formation into the additive manufacturing process itself, eliminating the need for separate machining operations and plugs. The cooling channels are integrated directly into the packing box structure during the 3D printing process, reducing both manufacturing complexity and potential leakage points.
Solution Approach 2:
The patent replaces traditional mechanical machining processes with additive manufacturing technology. Instead of drilling and machining cooling circuits after the packing box is formed, the cooling channels are created layer-by-layer during the additive manufacturing process, eliminating the need for complex post-processing and plug installation.
2Adaptability or versatility
If conventional cooling circuits are used in packing boxes, then cooling functionality is provided, but the cooling circuit shape and functionality are limited
Solution Approach 1:
The patent changes the manufacturing parameters from traditional subtractive machining to additive manufacturing, enabling complex three-dimensional cooling circuit geometries that were previously difficult or impossible to achieve. The additive process allows for variable cross-sections, curved paths, and optimized thermal pathways without increasing manufacturing complexity.
Solution Approach 2:
The patent transitions from two-dimensional cooling channel layouts to three-dimensional cooling circuits with arbitrary geometries. The additive manufacturing process enables cooling channels to wind through the packing box in complex three-dimensional paths, optimizing heat removal from multiple surfaces simultaneously.
3Reliability
If seal rings are used to prevent gas escape around the piston rod, then gas tight sealing is achieved, but sliding friction causes serious heating of the packing cups
Solution Approach 1:
The patent incorporates cooling channels directly into the packing cup structure during additive manufacturing, establishing cooling pathways before the friction heating problem occurs. The cooling circuits are pre-positioned to maximize heat removal from the packing cup surfaces that contact the seal rings and piston rod.
Solution Approach 2:
The patent applies localized cooling to specific areas of the packing cups where friction heating occurs most intensely. The additive manufacturing process enables cooling channels to be positioned precisely at thermal hotspots near the seal ring contact areas, providing targeted heat removal rather than uniform cooling throughout the entire packing cup.
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 provides a lighter, easier-to-manipulate packing box that enhances heat exchange efficiency between the metal and coolant, reduces friction, and prevents coolant leakage, thereby improving thermal management and mechanical performance.
Implementation Method 1
A fluid coolant introduced into the circular passageway flows between the inlet and outlet ports to absorb heat from the cup housing
Implementation Method 2
a liquid lubricant is typically introduced through a passageway in the packing case to the surface of the piston rod to reduce such sliding friction
Data Source
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AI summary
Described herein is a packing box (1) for mounting on a machinery shaft. In accordance with one aspect, the packing box housing defines a central opening (2) for insertion of a movable machinery shaft with a hollow passageway (103) surrounding the central opening to form a path for the flow of a fluid coolant. The passageway is provided with a fluid inlet port (105) and a fluid outlet port (104) opening onto the outer surface of the packing box housing, and it is formed by a single conduit or by a plurality of conduits obtained through additive manufacturing process and connected in series or in parallel to wound around the central opening.