Plastic Capillary Connection Element for Heating Systems
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing solutions for connecting plastic capillaries to heating systems or pressure gauges are prone to assembly-related damage, excessive tightening, and material limitations such as elasticity issues in capillaries, which affect pressure measurement accuracy and reliability.
Innovation Solution
A plastic connecting element with a sealing surface and O-ring, designed for easy installation without rotating the capillary end, featuring a metal sleeve for stabilization against pressure and temperature, and a locking mechanism with a fuse for secure engagement, ensuring predetermined tightness and resistance to damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a plastic capillary with elasticity is used to connect to the hose nipple, then the capillary can be slipped over the retaining projection without destruction, but the capillary migrates out of the clamping or is destroyed by the clamping under fluctuating pressure
Solution Approach 1:
A connecting element made of rigid or semi-rigid plastic serves as an intermediary component between the capillary and the hose nipple. This mediator provides a stable clamping interface that does not migrate under pressure fluctuations, while still allowing easy installation by slipping the capillary over the retaining projection. The connecting element absorbs the mechanical stresses and maintains a secure connection without damaging the capillary.
2Ease of operation
If the capillary elasticity is increased to facilitate installation, then the capillary can be easily slipped over the retaining projection, but the elasticity influences the pressure measurement by stretching
Solution Approach 1:
The connecting element acts as a mediator that decouples the installation ease from the measurement accuracy. The capillary can be made sufficiently elastic for easy installation, while the rigid connecting element ensures that no additional stretching occurs during operation, thus preserving measurement accuracy. The connecting element bears any mechanical loads without transmitting them to the capillary in a way that would cause stretching.
3Reliability
If soldering is used to connect metal capillary to the heating system, then a secure connection is achieved, but this solution is not applicable to plastic capillaries
Solution Approach 1:
The connecting element is designed with clamping parameters optimized for plastic materials. Instead of using soldering (which requires high temperature and is suitable for metals), the connecting element uses mechanical clamping forces and geometric interlocking features that are appropriate for plastic capillaries. This allows achieving secure connections while adapting to different material properties, particularly plastic materials that cannot be soldered.
4Reliability
If excessive tightening is applied to achieve high tightness, then connection tightness is improved, but the plastic capillary is pinched off and the connection is destroyed
Solution Approach 1:
The connecting element incorporates design features that cushion against excessive tightening forces before they can damage the capillary. This may include compliant elements, distributed clamping surfaces, or geometric features that limit the maximum clamping force. By providing this protective cushioning in advance, the connection achieves sufficient tightness without risking capillary damage, even if installation personnel apply excessive force.
Data Source
Figure 1
Figure 2
AI summary
The pressure-tight connection (3) for an extruded plastics capillary tube (1), to carry system pressure from a heating assembly to a pressure meter (6), is of injection molded plastics to hold the tube in a sealed fit. At least one shaped sealing surface has an O-ring (4). The connection is pushed into a holder (61) at the heating system and/or pressure meter, to be secured by a lock (2) pushed through as a clip.