Radiator Nipple Design with Toroidal Seal for Reduced Tightening Torque

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Solution Overview

Problem

Existing radiator nipples are heavy, expensive to manufacture, require high tightening torques, and often fail to maintain a fluid seal over time due to their large size and inadequate sealing mechanisms.

Innovation Solution

A lightweight nipple design featuring a cylindrical shape with inclined chamfers and a toroidal seat, combined with a radially arranged elliptic seal and teeth on the inner edge, ensures a secure and efficient hydraulic seal with reduced tightening torque, using a sealing wall and chamfers to evenly compress the seal, and inclined walls for assembly and radial blockage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If traditional hollow cylindrical nipples are used for connecting radiator elements, then the connection provides structural strength, but the nipple becomes heavy and expensive to manufacture

Engineering Contradiction:
Improveconnection strengthVSAvoidnipple weight
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The nipple is divided into multiple functional segments: an external threading portion for mechanical connection, a sealing portion with chamfers and toroidal seat for fluid sealing, and a reduced-thickness intermediate section. This segmentation allows each portion to be optimized independently, reducing overall material usage while maintaining connection strength.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different portions of the nipple have different wall thicknesses tailored to their specific functions. The threading portion maintains sufficient thickness for mechanical strength, while the intermediate section has reduced thickness to minimize weight. The sealing portion incorporates localized features (chamfers, toroidal seat) only where needed for sealing, rather than uniformly thickening the entire nipple.

Inventive Principle:
Principle #3Local quality

2Reliability

If traditional nipples are designed to ensure fluid seal, then sealing capability is achieved, but high tightening torques (up to 20 Kgm) are required

Engineering Contradiction:
Improvefluid seal reliabilityVSAvoidtightening torque
Core Design Contradiction:
ReliabilityVSForce

Solution Approach 1:

A toroidal seal element is introduced as an intermediary between the nipple and radiator element connecting ends. This seal mediator distributes the sealing load around the entire circumference, converting the concentrated high-torque requirement into a distributed low-torque application, thereby reducing the required tightening torque while maintaining reliable fluid sealing.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The toroidal (ring-shaped with circular cross-section) geometry of the seal provides curved contact surfaces that naturally distribute stress and pressure more evenly compared to flat sealing surfaces. This curvature allows the seal to conform to the mating surfaces and maintain sealing under lower clamping forces, reducing the required tightening torque.

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Duration of action of stationary object

If traditional nipples are used, then connection is achieved, but the sealing mechanism fails to maintain fluid seal over time

Engineering Contradiction:
Improvesealing durationVSAvoidfluid seal maintenance
Core Design Contradiction:
Duration of action of stationary objectVSReliability

Solution Approach 1:

The toroidal seal is pre-compressed between the chamfered surfaces of the nipple and the radiator element connecting ends during assembly. This pre-cushioning compensates for future settling, thermal expansion/contraction, and vibration, maintaining the fluid seal over time without requiring excessive initial tightening torque that could cause deformation or failure.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

4Ease of operation

If larger nipple sizes are used to reduce tightening torque, then assembly effort is reduced, but the nipple becomes heavier and more expensive

Engineering Contradiction:
Improveassembly effortVSAvoidnipple weight
Core Design Contradiction:
Ease of operationVSWeight of moving object

Solution Approach 1:

The invention changes the geometric parameters of the nipple, specifically the wall thickness distribution and the inclusion of chamfer angles, to optimize the balance between assembly effort and weight. By carefully selecting the thickness of each segment and the angles of the chamfers, the design achieves adequate sealing and connection with minimal material, reducing weight while keeping assembly torque requirements reasonable.

Inventive Principle:
Principle #35Parameter changes

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 results in a lighter, less expensive nipple that maintains a perfect fluid seal over time with reduced assembly effort, allowing for larger water flow and electrical resistance installation, while requiring only moderate tightening torque and ensuring even compression for long-term sealing performance.

Implementation Method 1

using a sealing wall and chamfers to evenly compress the seal

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 2

inclined walls for assembly and radial blockage

Methodology Applied
Scientific EffectMechanical Force: Mechanical Force

Data Source

PatentEP1949013B1Nipple for radiator elements, relative radiator elements and set of radiator elements
Publication Date: 2012.05.30 MECC LAN SRL
  • EP1949013B1 patent drawingFigure 1~2
  • EP1949013B1 patent drawingFigure 3~4
  • EP1949013B1 patent drawingFigure 5~7

AI summary

A nipple (4) for radiator elements (8) that allows a quick and safe connection between radiator elements (8), ensuring perfect fluid seal even over time. The nipple (4) is inexpensive and light to make, and requires an especially moderate tightening torque.