Explosion Proof Radar Level Gauge Intrinsic Safety Barrier

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Solution Overview

Problem

Existing radar level gauges designed for explosion proof environments cannot be connected to intrinsically safe power supplies without compromising safety regulations, as they typically require redesign and certification under specific standards.

Innovation Solution

A radar level gauge with an explosion proof housing and electrical barrier that prevents non-intrinsically safe energy from compromising an intrinsically safe system, using diodes and other components to ensure compatibility with both explosion proof and intrinsically safe standards, allowing connection to an intrinsically safe power supply while maintaining safety.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the radar level gauge is designed as explosion proof with circuitry having available electrical and thermal energy incompatible with intrinsic safety requirements, then the RLG can be connected to non-intrinsically safe power supplies, but it cannot be connected to intrinsically safe power supplies without compromising safety regulations

Engineering Contradiction:
Improvepower supply compatibilityVSAvoidsafety compliance
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent divides the RLG into two distinct segments: an explosion-proof compartment containing the high-energy circuitry and a low-energy interface for intrinsically safe connections. This segmentation allows each part to meet its specific safety requirements while enabling both IS and non-IS power supply compatibility.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediary barrier device that couples the intrinsically safe two-wire interface to the non-intrinsically safe RLG circuitry. This barrier acts as a mediator, allowing power and signals to pass through while ensuring that the IS side never receives more energy than intrinsic safety limits permit.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Power

If the RLG circuitry has available electrical and thermal energy incompatible with intrinsic safety requirements, then the RLG can operate with higher power, but redesign and certification are required under IEC 60079-11 standard

Engineering Contradiction:
Improveavailable electrical energyVSAvoidredesign and certification cost
Core Design Contradiction:
PowerVSEase of manufacture

Solution Approach 1:

The patent merges two different safety approaches (explosion-proof and intrinsically safe) into a single device. The RLG combines high-power explosion-proof circuitry with a low-power intrinsically safe interface, allowing it to operate with high power while connecting to intrinsically safe power supplies without requiring full IS certification.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If the RLG is designed to be intrinsically safe with an IS barrier, then it can be connected to IS power supply, but the available power is limited by the barrier

Engineering Contradiction:
Improveintrinsic safety complianceVSAvoidpower supply capability
Core Design Contradiction:
ReliabilityVSPower

Solution Approach 1:

The patent adds a spatial dimension to the power delivery architecture by creating separate energy domains: a high-energy domain for the RLG circuitry and a low-energy domain for the IS interface. The barrier operates in the low-energy domain while the RLG operates in the high-energy domain, allowing both to coexist without power limitations.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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

Enables connection to an intrinsically safe power supply without compromising safety regulations, reducing the need for costly redesign and certification, while ensuring the radar level gauge operates safely in hazardous environments.

Implementation Method 1

the electrical barrier includes at least one first diode connected in parallel between lines of the two-wire interface, thereby preventing negative voltages at the two-wire interface

Methodology Applied
Scientific EffectDiode: Diode

Implementation Method 2

the first signal passage providing a transmission line for the microwave transmit signal between the RLG circuitry and the signal propagation device

Methodology Applied
Scientific EffectMicrowave transmission: Microwave Radiation

Implementation Method 3

a signal propagating device arranged to direct microwaves towards the surface and to return microwaves reflected by the surface to the transceiver

Methodology Applied
Scientific EffectElectromagnetic wave reflection: Reflection

Data Source

PatentEP3462142B1Explosion proof radar level gauge
Publication Date: 2020.08.05 ROSEMOUNT TANK RADAR
  • EP3462142B1 patent drawingFigure 1
  • EP3462142B1 patent drawingFigure 2a~2b
  • EP3462142B1 patent drawingFigure 3

AI summary

A radar level gauge comprising a housing enclosing a compartment providing explosion proof protection, RLG circuitry located inside compartment, which circuitry is incompatible with intrinsic safety requirements, and a signal propagation device located outside the compartment. The housing has an explosion proof first signal passage providing a transmission line for the microwave transmit signal, and an explosion proof second signal passage in providing a two-wire interface for electrically conductively connecting the radar level gauge to an intrinsically safe system located externally of the radar level gauge. Further, the RLG includes an electrical barrier connected between the RLG circuitry and the two-wire interface, the electrical barrier preventing energy and/or thermal energy in the RLG circuitry from compromising the intrinsic safety of an intrinsically safe system connected to the two-wire interface.