Process Variable Transmitter Moisture Sensor Terminal Block

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Solution Overview

Problem

Process variable transmitters in industrial environments often fail due to moisture accumulation, leading to errors and device failure, as existing moisture detection techniques are inadequate in harsh conditions.

Innovation Solution

A process variable transmitter with a housing divided into two cavities, where measurement circuitry is in one cavity and a terminal block assembly with a moisture sensor in the other, allowing for early detection of moisture through impedance changes, providing a warning output before the device fails.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of information

If a terminal block assembly is used in process variable transmitters, then data transmission capability is improved, but moisture accumulation occurs leading to device failure

Engineering Contradiction:

Improvedata transmission reliabilityVSAvoiddevice reliability

Core Design Contradiction:

Loss of informationVSReliability

Solution Approach 1:

The moisture sensor is installed in the terminal block assembly to detect moisture accumulation before it causes device failure. This preliminary detection allows for early warning and preventive maintenance, resolving the contradiction by maintaining data transmission capability while preventing reliability degradation through advance moisture detection.

Inventive Principle:

Principle #10Preliminary action

2Difficulty of detecting and measuring

If traditional moisture detection techniques are used, then moisture detection capability is improved, but detection accuracy is insufficient in harsh industrial environments

Engineering Contradiction:

Improvemoisture detection capabilityVSAvoidmoisture detection accuracy

Core Design Contradiction:

Difficulty of detecting and measuringVSMeasurement precision

Solution Approach 1:

The patent replaces traditional mechanical or electrical moisture detection techniques with a capacitive moisture sensor that measures changes in electrical characteristics (capacitance) caused by moisture accumulation. This substitution provides more accurate and reliable moisture detection in harsh industrial environments, resolving the contradiction between detection capability and measurement precision.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 solution effectively prevents moisture-induced failures by providing an early warning of impending moisture accumulation, ensuring reliable data transmission and extending the transmitter's lifespan.

Implementation Method 1

A moisture sensor has an electrical characteristic which changes based upon the presence of moisture in at least one of the first and second cavities

Methodology Applied

Scientific EffectImpedance change: Electrical Resistance

Data Source

PatentEP3356770B1Process variable transmitter with terminal block moisture sensor

Publication Date: 2022.10.26 ROSEMOUNT INC

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Figure 2~3B
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AI summary

A process variable transmitter (12) for use in an industrial process includes a housing (102) having a cavity formed therein. The housing has a barrier which divides the cavity into first (104) and second cavities. Measurement circuitry (62) in the first cavity (104) is configured to measure a process variable of the industrial process. A terminal block assembly (108) is located in the second cavity (106). A moisture sensor (70) has an electrical characteristic which changes based upon the presence of moisture in the second cavity (106).