Sealed Cable Assembly for Flame Sensor Signal Integrity
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Solution Overview
Problem
Existing flame sensors in gas turbines face challenges in maintaining the integrity of low-magnitude current signals due to high temperature and vibration, leading to signal degradation, and there is a need for a durable and flexible cable assembly that can prevent moisture and contaminants from affecting the signal transmission.
Innovation Solution
A sealed cable assembly with a housing that includes a first and second cable end portion connected through a first seal, and a second seal in the annular spaces between the electrical cable and cable fittings to prevent moisture and contaminants, ensuring the signal remains intact across the cable assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a cable assembly is used to transfer low-magnitude current signals from the sensor near the combustion chamber to the flame sensing electronics, then the signal can be transferred over distance, but the signal degrades due to high temperature and vibration exposure
Solution Approach 1:
The cable assembly is segmented into multiple sealed sections with intermediate seals dividing the cable into segments. Each segment is independently sealed to prevent moisture and contaminant ingress along the entire cable length, thereby maintaining signal integrity in harsh environments
Solution Approach 2:
The cable assembly creates a sealed protective environment around the electrical cable, isolating it from the external harsh environment (high temperature, vibration, moisture, contaminants). This inert-like protected environment preserves the low-magnitude current signal from degradation
2Reliability
If the cable assembly is made more sealed and protective, then signal integrity is maintained, but the device complexity increases
Solution Approach 1:
The cable assembly uses a flexible protective sheath or jacket that seals around the electrical cable. This flexible shell provides environmental protection while maintaining cable flexibility and avoiding excessive structural complexity
Solution Approach 2:
The cable assembly acts as an intermediary protective structure between the sensor and the external environment. It mediates the transmission of electrical signals while blocking harmful environmental factors, simplifying the overall system design by consolidating protection functions
Data Source
AI summary
A flame sensor apparatus and a cable assembly apparatus are provided for use in sensing characteristics of a flame within a combustion chamber. The flame sensor apparatus includes an electrical assembly remote from a sensor assembly. A cable assembly extends between the sensor assembly and the electrical assembly. The cable assembly includes two cable ends and a housing that defines an internal volume. Cable fittings are connected to the cable ends through a first seal. An electrical cable is inserted through cable fitting openings in each cable fitting and the internal volume of the housing. A second seal is located in the annular spaces between the electrical cable and each cable fitting opening, configured to prevent moisture and contaminants from passing through the cable fitting opening. Additionally, a method of sealing an electrical cable and a flexible conduit is provided.