Intrinsically Safe Explosion-Proof Cable With Unshielded High-Frequency Unit
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Solution Overview
Problem
Conventional intrinsically safe explosion-proof compound cables require special structures that can cause signal waveforms to become blurred, especially when high-frequency signals are transmitted, due to the need for shielding which increases capacitance.
Innovation Solution
The solution involves configuring the compound cable with at least one unshielded unit cable for the highest-frequency signal transmission, and using a common barrier circuit to regulate signals or power across all unit cables, eliminating the need for shielding among them to prevent energy leaks and maintain signal clarity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If unit cables are shielded to prevent energy leak between cables, then intrinsic safety explosion-proof standard is satisfied, but signal waveform becomes blunt due to increased capacitance
Solution Approach 1:
The compound cable is segmented into multiple unit cables, where only the highest-frequency unit cable is left unshielded while other unit cables are shielded. This segmentation allows selective application of shielding based on frequency requirements, resolving the contradiction between explosion-proof safety and signal quality.
Solution Approach 2:
Different unit cables are assigned different shielding qualities based on their signal frequency characteristics. The highest-frequency unit cable is unshielded to maintain signal quality, while other unit cables are shielded to ensure explosion-proof safety. This local differentiation resolves the universal shielding requirement contradiction.
2Object-affected harmful factors
If all unit cables are shielded to prevent energy leak, then safety standard is met, but high-frequency signals experience waveform degradation
Solution Approach 1:
Instead of shielding all unit cables (excessive action), only the necessary unit cables are shielded (partial action). The highest-frequency unit cable is excluded from shielding since it most requires signal integrity, while other unit cables are shielded to prevent energy leak. This partial application resolves the contradiction between safety and signal quality.
3Reliability
If common barrier circuit is used to regulate all unit cables, then intrinsic safety is achieved, but shielding becomes unnecessary for highest-frequency cable
Solution Approach 1:
Multiple unit cables are regulated as a whole by a common barrier circuit, merging the control function. This allows the highest-frequency unit cable to be unshielded while still maintaining intrinsic safety through the common regulation, reducing cable structure complexity while ensuring safety.
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
This configuration ensures that the compound cable meets the intrinsic safety explosion-proof standard while preventing signal blurring, even at high frequencies, thereby maintaining signal integrity and preventing electromagnetic leakage.
Implementation Method 1
a signal which satisfies the intrinsic safety explosion-proof standard by an insulated barrier is outputted to a 2-wire cable as an intrinsically safe explosion-proof cable
Implementation Method 2
the unit cables must be mutually separated by shields
Implementation Method 3
the shielded unit cable has a large capacitance compared with an unshielded unit cable
Data Source
AI summary
An intrinsically safe explosion-proof compound cable includes a plurality of unit cables. Each of the unit cables is configured to transmit a signal or power. The plurality of unit cables include one or more shielded cables each having a shield layer and one or more unshielded cables without the shield layer. At least a highest-frequency unit cable that is the unit cable configured to transmit the signal or power at the highest frequency among the plurality of unit cables is the unshielded cable.