Rotating Liquid Layer Sensor for Degassing Centrifugal Pumps

Solution Overview

Problem

Existing degassing centrifugal pumps are vulnerable to mechanical failures and dirt build-up, leading to unreliable measurements of liquid layer thickness, which affects the efficiency of gas removal in papermaking processes.

Innovation Solution

A rotatable sensor attached to the second impeller or shaft of the degassing centrifugal apparatus measures the liquid layer thickness, reducing dirt build-up and mechanical failure risks by eliminating the need for a long pipe attachment, and using capacitance, light beam, or sounder measurements to provide reliable data.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a static sensor on a long thick-walled pipe is used to measure liquid layer thickness, then the measurement can be obtained, but the sensor is vulnerable to mechanical failures and dirt build-up

Engineering Contradiction:

Improveliquid layer thickness measurementVSAvoidsensor mechanical reliability

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent inverts the conventional static sensor arrangement by using a rotatable sensor that rotates together with the rotor. This inversion transforms the sensor from a stationary, vulnerable position to a rotating position that moves with the fluid flow, reducing dirt accumulation and mechanical stress while maintaining measurement capability.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent replaces the mechanical connection of a long thick-walled pipe with a rotatable sensor directly mounted on the rotor. This substitution eliminates the vulnerable pipe structure and its associated mechanical failure points, while the rotatable sensor maintains reliable mechanical attachment through direct mounting on the rotor structure.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If a static sensor on a long pipe is used, then the liquid layer thickness can be measured, but the long pipe is vulnerable to vibration reducing measurement reliability

Engineering Contradiction:

Improveliquid layer thickness measurementVSAvoidsensor system stability

Core Design Contradiction:

Measurement precisionVSStability of the object's composition

Solution Approach 1:

The patent inverts the conventional static sensor arrangement by using a rotatable sensor that rotates together with the rotor. This inversion transforms the sensor from a stationary, vulnerable position to a rotating position that moves with the fluid flow, reducing dirt accumulation and mechanical stress while maintaining measurement capability.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent merges the sensor with the rotor by mounting it directly on the rotor structure, causing them to rotate together. This merging eliminates the separate, vulnerable pipe structure and integrates the sensor into the rotating assembly, reducing vibration susceptibility and improving measurement stability.

Inventive Principle:

Principle #5Merging (Combining)

3Reliability

If a rotatable sensor is used, then dirt build-up is reduced and mechanical reliability is improved, but the sensor arrangement becomes more complex

Engineering Contradiction:

Improvesensor mechanical reliabilityVSAvoidsensor arrangement complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the sensor with the rotor by mounting it directly on the rotor structure, causing them to rotate together. This merging eliminates the separate, vulnerable pipe structure and integrates the sensor into the rotating assembly, reducing vibration susceptibility and improving measurement stability.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The rotatable sensor serves multiple functions: it measures liquid layer thickness, rotates with the rotor to minimize dirt accumulation, and integrates with the rotor structure to reduce mechanical vulnerability. This multi-functionality justifies the increased complexity by delivering multiple benefits from a single integrated component.

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

The solution enhances the reliability of liquid layer thickness measurements, reduces dirt build-up, and minimizes the need for compensation, resulting in improved gas separation efficiency and consistent fluid flow in papermaking processes.

Implementation Method 1

the sensor is arranged to measure the mutual capacitance of said liquid layer and said sensor

Methodology Applied

Scientific EffectMutual capacitance: Capacitance

Implementation Method 2

a rotatable hollow rotor connected to a stationary fluid inlet at one end portion and a stationary liquid outlet at the opposite end portion, and having a gas exhaust for removing gas from the center thereof

Methodology Applied

Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentUS20090201975A1Degassing centrifugal apparatus with sensor

Publication Date: 2009.08.13 AIKAWA FIBER TECH

AI summary

The present invention relates to a degassing centrifugal apparatus (10), such as a degassing centrifugal pump (10) for use in a pulp- or papermaking process. The degassing centrifugal apparatus (10) according to the present invention comprises a rotatable hollow rotor (20) connected to a stationary fluid inlet (14) at one end portion and a stationary liquid outlet (18) at the opposite end portion, and having a gas exhaust (36) for removing gas from the centre thereof. The apparatus further comprises at said inlet end portion means (24) for rotating said fluid and directing it to the inner wall of said rotor (20). The apparatus further comprises a rotatable sensor (42) arranged to measure the layer thickness of a liquid (40) rotating in said apparatus.