Propeller Shaft Air Chamber Draft Measurement for Fluctuating Vessels

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Solution Overview

Problem

Current methods for identifying a vessel's draft are time-consuming and labor-intensive, especially when the draft is fluctuating, making it difficult to accumulate time-series data for IoT implementation.

Innovation Solution

A draft meter system with seal rings around the propeller shaft, an air chamber, and an oil chamber, equipped with a pressure gauge, data storage, and an arithmetic unit that calculates draft by measuring pressure differences and seawater density data.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If manual draft measurement by measurer boarding small boat is used, then measurement can be performed, but it is time-consuming and laborious

Engineering Contradiction:
Improvedraft measurementVSAvoidmeasurement time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent replaces the manual mechanical measurement system (measurer boarding boat with draft measuring device) with an automated sensor-based system. Draft sensors detect the draft automatically, and this data is transmitted via communication units to identify draft information, eliminating the need for manual measurement operations.

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

Solution Approach 2:

The vessel performs draft measurement automatically through onboard draft sensors and communication units without requiring external human operators. The system self-identifies draft information and can transmit it to external devices, enabling the vessel to service its own measurement needs.

Inventive Principle:
Principle #25Self-service

2Measurement precision

If manual draft measurement is used, then draft can be identified, but it is difficult to identify draft at freely-selected timing due to constant fluctuation

Engineering Contradiction:
Improvedraft identificationVSAvoidtiming flexibility
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The draft sensors continuously detect draft information at all times, providing continuous data availability. This allows draft to be identified at any freely-selected timing regardless of fluctuations, as the measurement system operates continuously rather than requiring discrete manual interventions.

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The automated sensor system enables continuous, real-time draft monitoring without the timing constraints of manual measurement, allowing draft identification at any desired moment.

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

3Loss of information

If manual draft measurement is used, then draft data can be obtained, but time-series data for IoT implementation cannot be accumulated

Engineering Contradiction:
Improvedraft dataVSAvoiddata accumulation efficiency
Core Design Contradiction:
Loss of informationVSProductivity

Solution Approach 1:

The continuous operation of draft sensors generates a continuous stream of draft data, enabling accumulation of time-series data necessary for IoT applications. Multiple data points over time can be collected automatically without manual intervention.

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The automated measurement and communication system enables efficient data accumulation by automatically collecting, storing, and transmitting draft data over time, facilitating IoT implementation without manual data gathering processes.

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

Enables real-time identification of fluctuating drafts, facilitating the accumulation of time-series data for IoT applications in vessels.

Implementation Method 1

having a pressure gauge for measuring pressure in the air chamber

Methodology Applied
Scientific EffectPressure measurement:

Data Source

PatentEP3854674B1Draught meter and vessel
Publication Date: 2022.05.18 WARTSILA JAPAN
  • EP3854674B1 patent drawingFigure 1
  • EP3854674B1 patent drawingFigure 2
  • EP3854674B1 patent drawingFigure 3

AI summary

A draft meter to be used for a vessel in which a plurality of seal rings are arranged around a propeller shaft at intervals in an axial direction of the propeller shaft, an air chamber and an oil chamber in this order from a stern side are provided by the plurality of seal rings, and an air control unit is connected to the air chamber via an air supply channel, and having a pressure gauge for measuring pressure in the air chamber, includes: a data storage unit and an arithmetic unit, wherein the data storage unit is configured such that predetermined correction data and predetermined seawater density data are stored and that pressure data measured by the pressure gauge is received, and wherein the arithmetic unit is configured to identify a draft of the vessel by calculating a difference value between the pressure data and the correction data and by dividing the difference value by the seawater density data.