Field device for use in hygienic applications in process- and automation technology and method for its manufacture
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Solution Overview
Problem
Field devices in hygienic process automation applications face condensation issues due to high humidity, leading to corrosion, short-circuits, and defective measurements, particularly in pressure measuring devices, where condensate blocks reference air ducts, and existing solutions like larger housings or temperature decouplers are costly or inefficient.
Innovation Solution
A field device with a heating element integrated into the housing, connected in parallel with the electrical circuit, using standard electronic components like SMD-resistors or field effect transistors, which is powered directly from the external energy supply, ensuring reliable operation by maintaining the housing temperature above the dewpoint temperature without additional energy sources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the housing dimensions are increased to locate sensitive components away from the process connection, then condensation protection is improved, but material costs and space requirements increase
Solution Approach 1:
The patent changes the temperature parameter of the housing by introducing a heating element that actively heats the housing to maintain its temperature above the dewpoint. This allows the housing to remain compact while still preventing condensation, resolving the contradiction between compact dimensions and condensation protection.
Solution Approach 2:
The patent replaces the mechanical solution of increasing housing dimensions with a thermal solution using an electric heating element. Instead of physically distancing components from the cold environment, the system actively manages temperature to prevent condensation, achieving the same protective effect with a compact design.
2Reliability
If temperature decouplers with special housing forms are used, then condensation protection is improved, but manufacturing complexity and development effort increase
Solution Approach 1:
The patent replaces complex mechanical housing structures (ribs, constrictions) with a simple thermal management system using a heating element. This achieves condensation protection through temperature control rather than through complex geometric designs, reducing manufacturing complexity.
Solution Approach 2:
The heating element serves multiple functions: it heats the housing to prevent condensation, and can potentially serve as part of the temperature management system for the electronics. This multi-functionality simplifies the overall design compared to dedicated structural decouplers.
3Reliability
If a heating element is integrated into the field device, then condensation protection is improved, but energy consumption and control complexity increase
Solution Approach 1:
The heating element is activated only when needed - specifically during cooling phases when condensation risk occurs. The control system monitors process conditions and switches the heater on/off accordingly, rather than operating continuously. This periodic operation reduces overall energy consumption while maintaining condensation protection when required.
Solution Approach 2:
The control loop monitors the process temperature and activates the heating element based on actual conditions. When the process temperature drops below a threshold (indicating condensation risk), the heater is activated. This feedback-based control ensures energy is used only when necessary for condensation protection.
4Device complexity
If the heating element is connected in parallel to the electrical current loop, then device complexity is reduced, but measurement precision may be affected
Solution Approach 1:
The electrical system is segmented into two independent parallel circuits: one for measurement (4-20 mA current loop) and one for heating. This segmentation allows both functions to operate simultaneously without interfering with each other, maintaining measurement precision while simplifying the overall electrical architecture by using the existing connection infrastructure.
Solution Approach 2:
The existing electrical connection infrastructure is made multi-functional by connecting both the measurement circuit and the heating element to the same external power supply. This universal use of the electrical interface reduces connection complexity while maintaining functional independence through parallel circuit design.
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 solution effectively prevents condensate formation, reducing the risk of corrosion and measurement errors while being cost-effective and efficient, as the heating element does not interfere with measurement results and can be turned on only during low-temperature phases, conserving energy.
Implementation Method 1
at least one heating element... the heating element is in electrical contact with the external energy unit... the heating element heats the housing and electronics to prevent condensation
Data Source
AI summary
A field device for use in hygienic applications in process and automation technology is disclosed, including a sensor element, an electrical circuit, a heating element, a housing, having an outside and an inside in which the sensor element, the electrical circuit and the heating element are arranged and mounted, and an external energy supply unit, wherein the field device possesses two connection pins, to which the sensor element and the electrical circuit are connected and enabling an electrical connection with the external electrical current supply, whereby forming a first electrical current loop, and wherein a second electrical current loop is arranged such that the heating element is in electrical contact with the external energy unit via one of the two connection pins and a third connection pin, whereby the second electrical current loop forms a parallel circuit with the first electrical current loop.