External Sensor Solids Level Indicator for High-Temperature Vessels

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Solution Overview

Problem

Conventional solids level indicators in high-temperature and pressure vessels, such as continuous digesters and impregnation vessels, face issues like sensor damage from uneven expansion, distortion of shafts, and the need for precise design for each vessel type, leading to inaccurate measurements and prolonged shutdowns for replacement, resulting in loss of production.

Innovation Solution

A modular external sensor system with a rotary end torsionally communicating with a solid torsion shaft and a stationary end connected to a support structure, allowing for easy removal and replacement without extracting the torsion shaft, incorporating a torsion spring to manage excess force and maintain accurate measurements across varying conditions, and using a stronger solid torsion shaft with a plug cap for adjustable paddle orientation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a hollow shaft with internal sensors is used, then the sensor can be housed within the shaft, but the high temperature causes uneven expansion and distortion leading to sensor damage and measurement inaccuracy

Engineering Contradiction:
Improvesensor housing integrationVSAvoidsensor measurement accuracy
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The sensor is extracted from the hollow shaft interior and repositioned to the exterior surface of the shaft. This allows the sensor to measure shaft deflection without being subjected to the high-temperature environment inside the vessel, eliminating the problem of thermal expansion damage while maintaining the functional integration of the measurement system.

Inventive Principle:
Principle #2Taking out (Extraction)

2Ease of repair

If the shaft is removed from the vessel for sensor replacement, then the sensor can be maintained or replaced, but production shutdown is required resulting in loss of production

Engineering Contradiction:
Improvesensor replacement accessibilityVSAvoidproduction continuity
Core Design Contradiction:
Ease of repairVSProductivity

Solution Approach 1:

The sensor is replaced with an optical sensor that measures shaft deflection optically rather than mechanically. This allows the sensor to be positioned externally where it can be maintained or replaced without removing the shaft from the vessel, enabling in-situ maintenance and eliminating production shutdowns.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If a precise design is created for each vessel type, then the sensor can be optimized for specific vessel conditions, but the design and manufacturing becomes more complex and time-consuming

Engineering Contradiction:
Improvesolids level measurement accuracyVSAvoidsensor assembly fabrication
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The sensor assembly is designed with universal components including a standardized clamp mechanism that can accommodate different shaft diameters and vessel types. The optical sensor and support structure can be configured for various measurement requirements without requiring custom-designed sensor housings for each specific vessel, simplifying manufacturing while maintaining measurement precision.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 accurate solids level measurement in high-temperature and pressure vessels without requiring shutdowns, allowing for in-situ maintenance and adjustment, reducing production losses and extending the lifespan of the solids level indicators.

Implementation Method 1

a rotary end (640) adjacently disposed to a stationary end (660), wherein the rotary end (640) is adjacently disposed to the shaft exterior end (730) and the shaft exterior end (730) torsionally communicates with the adjacently disposed rotary end (640)

Methodology Applied
Scientific EffectTorsion: Torque

Implementation Method 2

incorporating a torsion spring to manage excess force and maintain accurate measurements across varying conditions

Methodology Applied
Scientific EffectTorsion spring: Torsion Spring

Data Source

PatentEP3460421B1Solids level indicator assembly
Publication Date: 2020.12.16 ANDRITZ INC
  • EP3460421B1 patent drawingFigure 1
  • EP3460421B1 patent drawingFigure 2
  • EP3460421B1 patent drawingFigure 3~4

AI summary

This disclosure describes a level indicator assembly for measuring the level of solids in a vessel. The level indicator may desirably comprise a solid shaft extending into a vessel. The shaft may have paddle connected to an interior end of the shaft and an external sensor attached to an exterior end of the shaft. A support structure may engage the sensor to prevent at least a portion of the sensor from moving. By keeping a portion of the sensor stationary, the sensor may measure the change in torsional force exerted on the shaft. By locating the sensor external to the vessel, operators may remove and replace sensors without accessing either the vessel interior or the portions of the level indicator assembly that extend into the vessel.