Compact Modular Surge Protection Device for Field Devices

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Solution Overview

Problem

Existing surge protection devices for field devices are not compact enough to fit within the limited space of explosion-proof field devices and are not easily replaceable when damaged by surge voltage, complicating wiring and maintenance.

Innovation Solution

A modular surge protection device with a compact design that includes terminal fittings connected to power supply terminals, a circuit board with a surge protection element, and an earth wiring cable, allowing easy installation and replacement, with the terminal fittings and earth wiring cable protruding from the main body to facilitate connection to power supply and earth terminals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a surge protection device is mounted on a circuit board or installed as a surge protection module, then the field device is protected from surge voltage, but the device occupies significant space and is difficult to replace when damaged

Engineering Contradiction:
Improvesurge protection capabilityVSAvoidreplaceability of surge protection device
Core Design Contradiction:
ReliabilityVSEase of repair

Solution Approach 1:

The surge protection device is designed as a separable component that can be independently replaced. The terminal fittings are detachably connected to the circuit board, allowing the surge protection device to be segmented from the main field device body. This enables easy replacement of the surge protection element without replacing the entire field device or complex wiring infrastructure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The surge protection device is extracted as a distinct, removable module from the field device. The terminal fittings serve as the extraction interface, allowing the surge protection device to be taken out and replaced independently. This extraction approach simplifies maintenance by isolating the replaceable surge protection component from the permanent field device structure.

Inventive Principle:
Principle #2Taking out (Extraction)

2Reliability

If a surge protection device is installed in the field device, then surge voltage protection is provided, but the device size is too large to fit within the limited space of explosion-proof field devices

Engineering Contradiction:
Improvesurge voltage protectionVSAvoiddevice size
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The terminal fittings are designed to nest within or attach to the existing terminal block structure of the field device. The surge protection device utilizes the existing space and mounting infrastructure, nesting its components within the available volume rather than requiring separate external mounting space. This nesting approach allows the surge protection function to be integrated into the limited space of explosion-proof field devices.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Reliability

If terminal fittings are connected to power supply terminals with power supply cable, then electrical power is supplied to the field device, but wiring complexity increases when surge protection device is installed

Engineering Contradiction:
Improvepower supply connectionVSAvoidwiring complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The terminal fittings serve a dual function: they provide power supply connection to the field device and simultaneously serve as the connection interface for the surge protection device. By merging these two functions into a single component, the wiring complexity is reduced. The power supply cable connects to the terminal fittings, which then distribute power to both the field device and the surge protection device, eliminating the need for separate wiring paths.

Inventive Principle:
Principle #5Merging (Combining)

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 compact and modular design allows for efficient protection of field devices from surge voltage while enabling easy replacement of the surge protection device, reducing the complexity of wiring and maintenance, and ensuring reliable operation.

Implementation Method 1

a surge protection element mounted on the circuit board, the surge protection element including two electrodes connected to the pair of terminal fittings and a ground electrode configured to cause a surge current to flow

Methodology Applied
Scientific EffectSurge protection element operation: Avalanche Breakdown

Data Source

PatentEP3208899B1Surge protection device and field device including surge protection device
Publication Date: 2019.10.16 YOKOGAWA ELECTRIC CORP
  • EP3208899B1 patent drawingFigure 1
  • EP3208899B1 patent drawingFigure 2A~2D
  • EP3208899B1 patent drawingFigure 3~4

AI summary

A surge protection device includes: a pair of terminal fittings to be connected to a pair of power supply terminals of a field device together with a power supply cable; a circuit board on which a surge protection element is mounted, the surge protection element including two electrodes connected to the pair of terminal fittings and a ground electrode configured to cause a surge current to flow to a ground when a surge voltage is applied between the two electrodes; an earth wiring cable connected to the ground electrode; and a main body that houses the circuit board, the main body being configured such that the pair of terminal fittings and the earth wiring cable protrude from an inside of the main body to an outside.