Spring-Loaded Moisture Sensor for Pulp Belt Pressure Control

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Solution Overview

Problem

Existing moisture measurement systems in paper production plants do not account for the pressure with which the measuring device is pressed against the sieve belt, leading to suboptimal control of the drying process.

Innovation Solution

A measuring stick with a device that determines and maintains a predetermined contact pressure range by using a spring-loaded moisture sensor with a ceramic support and position sensor, ensuring accurate moisture measurements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the measuring device is pressed against the sieve belt without pressure control, then the measurement process is simple, but the measurement precision deteriorates due to variable contact pressure

Engineering Contradiction:
Improvemoisture measurement accuracyVSAvoidmeasurement system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by controlling the contact pressure parameter within a specific range (0.5-2 bar) to optimize moisture measurement accuracy. The spring element automatically adjusts the pressing force to maintain this pressure parameter, ensuring consistent measurement conditions without requiring complex active control systems.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements feedback through position sensors that detect the displacement of the measuring device and provide information to the control unit. This feedback mechanism allows the system to automatically adjust and maintain the contact pressure within the optimal range, improving measurement precision while keeping the overall system relatively simple.

Inventive Principle:
Principle #23Feedback

2Reliability

If the moisture sensor is directly exposed to the pulp material, then the measurement response is fast, but the reliability deteriorates due to liquid ingress and wear

Engineering Contradiction:
Improvedevice durabilityVSAvoidmeasurement accessibility
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent uses a sieve belt with mesh openings that acts as a flexible barrier, allowing moisture measurements through the belt while protecting the sensor from direct contact with pulp material. This enables the sensor to remain in a protected environment while still measuring the moisture content of the material on the other side of the belt.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The sieve belt serves as an intermediary between the moisture sensor and the pulp material. It allows the measurement function to be performed while simultaneously protecting the sensor from wear and liquid ingress, thus improving reliability without significantly complicating the measurement process.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If the measuring device applies high pressure to ensure contact, then the contact reliability is improved, but the moisture measurement precision deteriorates due to compression of the pulp material

Engineering Contradiction:
Improvemoisture content accuracyVSAvoidcontact pressure
Core Design Contradiction:
Measurement precisionVSForce

Solution Approach 1:

The patent optimizes the contact pressure parameter by defining a specific range (0.5-2 bar) that balances sufficient contact for reliable measurement with avoidance of excessive compression that would alter the pulp material's moisture content. This parameter optimization ensures accurate measurements without damaging the material structure.

Inventive Principle:
Principle #35Parameter changes

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 precise moisture content measurement by maintaining consistent contact pressure, improving the control of the drying process and extending the device's operational lifespan by preventing liquid ingress.

Implementation Method 1

a spring element, by means of which the sensor can be pressed onto the underside of the sieve belt

Methodology Applied
Scientific EffectSpring force: Spring

Implementation Method 2

a sensor for measuring the moisture content of the pulp material located on the sieve belt

Methodology Applied
Scientific EffectMoisture sensing: Hygrometer

Implementation Method 3

the sensor is designed with a wear-resistant support, in particular a plate made of a ceramic material

Methodology Applied
Scientific EffectWear resistance: Wear

Implementation Method 4

the sensor and the housing are preferably sealed against the ingress of liquid by means of an elastic sealing collar and optionally by means of at least one sealing ring

Methodology Applied
Scientific EffectSealing: Physical Containment

Data Source

PatentEP3239395B1Device for measuring the humidity of pulp material located on a filtering belt
Publication Date: 2019.05.08 BARTELMUSS KLAUS
  • EP3239395B1 patent drawingFigure 1
  • EP3239395B1 patent drawingFigure 2~2C
  • EP3239395B1 patent drawingFigure 3

AI summary

Method and apparatus for measuring the moisture content of the pulp material (12) located on a wire belt (11) in a paper production plant, comprising a device (2) for measuring the moisture content of the pulp material, which includes a moisture sensor (22), and an associated control and data processing unit (5), as well as a transmitter and receiver and/or a connection for a data line for transmitting the measurement data to the control and data processing unit. The device (2) for measuring the moisture content of the pulp material is equipped with a measuring device (6) for determining and displaying the pressure range with which it is pressed against the wire belt (11).