Field Device Terminal PCB Insulation for Ex ec Creepage Distance
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Solution Overview
Problem
Existing field devices for automation technology face challenges in maintaining the required creepage distance for ignition protection in potentially explosive atmospheres, especially when using non-conductive potting compounds that may penetrate recesses on circuit boards, compromising the specified type of ignition protection.
Innovation Solution
An elongated component with ribs is inserted into the recesses of a circuit board, providing an air gap and additional creepage distance, secured by stop supports, to maintain the required ignition protection without increasing board dimensions, using non-conductive materials like plastic.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the distance between terminals is increased to ensure ignition protection, then the creepage distance is improved, but the circuit board dimensions increase
Solution Approach 1:
The invention introduces a vertical dimension by adding an elongated insulating component that protrudes from the circuit board surface. This creates a three-dimensional creepage path instead of relying solely on two-dimensional surface distance, allowing adequate creepage distance while maintaining compact board dimensions.
Solution Approach 2:
The elongated insulating component acts as an intermediary element between adjacent terminals. It provides additional creepage distance through its length and creates air gaps that increase the effective creepage path, serving as a mediator that enables ignition protection without expanding the overall board footprint.
2Strength
If non-conductive potting compound is used to fill the housing, then mechanical protection is improved, but the creepage distance is reduced due to material penetration into recesses
Solution Approach 1:
The elongated insulating component is installed on the circuit board before the potting compound is applied. This preliminary action ensures that the component's protruding portions extend into the recesses and maintain the required creepage distance, preventing the potting compound from bridging the insulation path between terminals.
Solution Approach 2:
By extending the insulating component vertically from the circuit board surface, the invention creates a multi-dimensional creepage path. This vertical extension ensures that even when potting compound fills the housing recesses, the creepage distance is maintained through the air gap and the length of the protruding component.
3Reliability
If the creepage distance is increased through larger terminal spacing, then ignition protection is improved, but device miniaturization is hindered
Solution Approach 1:
The invention resolves the contradiction by transitioning from two-dimensional terminal spacing to three-dimensional creepage path management. The elongated insulating component adds vertical height to the creepage path, enabling adequate ignition protection while maintaining small horizontal dimensions for device miniaturization.
Solution Approach 2:
The invention effectively creates an air-filled porous structure between terminals through the elongated insulating component with its protruding portions. This air gap structure provides high insulation resistance and adequate creepage distance while occupying minimal space, enabling both ignition protection and miniaturization.
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
Ensures compliance with ignition protection standards like Ex ec, allowing safe use in explosive atmospheres by preventing short circuits, while enabling miniaturization and using standard components across different explosion protection variants.
Implementation Method 1
The invention creates an air gap in addition to the creepage distance on the circuit board along the direct connection line between two terminals... Since air has a higher resistance than the circuit board, the creepage distance is increased by the intervening air gap.
Data Source
Figure 1
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Figure 4~5
AI summary
The invention relates to an apparatus for electrically contacting the control/evaluation electronics (1) of a field device in automation technology with an external energy supply and/or control, wherein: the control/evaluation electronics (1) of the field device are arranged on a circuit board (2); at least one terminal housing (3) is provided in which a plurality of electrical connector terminals (4), arranged adjacent to one another, are provided; the electrical connector terminals (4) each serve to receive an electrical connection element (5); the electrical connection elements (5) are each mechanically and electrically connected by means of a solder pad (6) to the circuit board (2); and between each pair of solder pads (6) in the circuit board (2), recesses (7) are provided that are designed such that the length of the creepage distance between the solder pads (6) meets a predefined ignition protection class.