Shell-and-tube distribution device with welded modules

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Solution Overview

Problem

Existing shell-and-tube equipment for urea production experiences significant leakage and uneven distribution of the urea and urea carbamate solution due to mechanical tolerances and irregularities in the distribution device, leading to inefficient performance.

Innovation Solution

A shell-and-tube equipment with a distribution device featuring a plurality of channel modules with circular trapezoid-shaped base plates and vertically arranged walls, joined by arc-shaped welding, and flanged portions with Teflon gaskets to ensure tightness and even fluid distribution, reducing leakage and facilitating assembly through a self-supporting design.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the distribution device is assembled using multiple metal sheets joined by bolts, then the device can be manufactured and assembled, but mechanical tolerances and irregularities cause significant fluid leakage

Engineering Contradiction:
Improveassembly capabilityVSAvoidtightness
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent changes the joining method from mechanical (bolts) to thermal (welding), fundamentally altering the connection parameters to eliminate leakage while maintaining assembly capability. The welding process creates a continuous metallurgical bond that eliminates the gaps present in bolted connections.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent merges multiple separate metal sheets into a single integrated structure through welding. The channel modules are welded together to form a unified distribution device, eliminating the interfaces between separate components that would otherwise allow leakage.

Inventive Principle:
Principle #5Merging (Combining)

2Ease of operation

If the distribution device uses a traditional bolted assembly, then assembly is possible, but the device cannot guarantee perfect tightness and significant leakage occurs

Engineering Contradiction:
ImproveassemblyVSAvoidfluid leakage
Core Design Contradiction:
Ease of operationVSLoss of substance

Solution Approach 1:

The patent changes the joining parameter from mechanical fastening (bolts with gaps) to thermal fusion (welding), transforming the connection from discrete contact points to a continuous bonded interface that prevents fluid leakage while maintaining ease of assembly through standardized welding procedures.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If the distribution device is manufactured as a single integrated component, then tightness would be improved, but the device would be difficult to assemble and maintain through the existing manhole

Engineering Contradiction:
ImprovetightnessVSAvoidassembly
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent divides the distribution device into modular channel sections that can be assembled in segments through the existing manhole. Each module is designed to fit through the 600mm manhole opening, allowing the device to be constructed in a practically assembled state rather than requiring complete disassembly for maintenance.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent designs the channel modules with nested dimensions that allow them to be inserted through the manhole opening. The modular sections are dimensioned to fit within the constraints of the existing access opening, enabling assembly and maintenance without requiring larger openings or complete disassembly.

Inventive Principle:
Principle #7Nested doll (Nesting)

4Reliability

If Teflon gaskets are used between metal sheets, then leakage is reduced, but mechanical tolerances and irregularities still cause significant fluid leakage

Engineering Contradiction:
ImprovetightnessVSAvoidfluid leakage
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The patent changes the sealing mechanism from relying on compliant gaskets within mechanical joints to creating a rigid, continuous metallurgical bond through welding. This fundamental parameter change eliminates the interface gaps that limit gasket effectiveness and directly prevents leakage through the joined structure.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3476470B1Shell-and-tube equipment with distribution device
Publication Date: 2022.11.09 ALFA LAVAL OLMI SPA
  • EP3476470B1 patent drawingFigure 1
  • EP3476470B1 patent drawingFigure 2~2A
  • EP3476470B1 patent drawingFigure 3~5

AI summary

A shell-and-tube equipment (10) has a cylindrical geometry and is arranged along a vertical axis (A). The shell-and-tube equipment (10) comprises an upper chamber (12) and a lower chamber (14) connected to a common tube bundle (16) on opposite sides. The upper chamber (12) is provided with at least an inlet nozzle (18) for inletting a first fluid. The tube bundle (16) is surrounded by a shell (20) provided with nozzles (22; 24) for inletting and outletting a second fluid which exchanges heat with the first fluid through the tube bundle (16). The upper chamber (12) encloses at least a distribution device (26) configured for uniformly delivering the first fluid towards the tube bundle (16). The distribution device (26) comprises an annular channel (28) which is arranged around the vertical axis (A) and is in fluid communication with the inlet nozzle (18). The distribution device (26) comprises a plurality of channel modules (30) of circular trapezoid shape, tightly joined together at their respective vertical edges for forming the annular channel (28).