Integrated Lubricant Level Sensing for Pump Auto-Fill Shutoff

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Solution Overview

Problem

Existing lubrication systems lack an efficient method for sensing the lubricant level in reservoirs, leading to potential over-lubrication or under-lubrication of machinery components.

Innovation Solution

A lubricant pump assembly that includes a sensor assembly with a sensor tube containing sensors, a magnetic indicator, and a fill tube, where the magnetic indicator triggers the sensors to output signals indicative of the lubricant fill level, allowing for accurate monitoring and auto-fill shut-off.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If no level sensing mechanism is installed, then the device complexity is reduced, but the reliability of lubrication is compromised leading to potential over-lubrication or under-lubrication

Engineering Contradiction:
Improvereliability of lubricationVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical level sensing mechanisms with a magnetic field-based sensing system. The magnetic indicator and sensors utilize magnetic field interaction to detect lubricant levels without mechanical contact, eliminating the need for complex mechanical linkages while improving reliability.

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

Solution Approach 2:

The patent introduces a magnetic indicator as an intermediary element that transfers level information from the lubricant environment to the sensors. This magnetic intermediary enables non-contact sensing, resolving the contradiction between reliability and complexity by providing accurate level detection without complex mechanical structures.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If the sensors are placed directly in contact with the lubricant, then the measurement precision is improved, but the sensors are exposed to harmful factors from the lubricant

Engineering Contradiction:
Improvelubricant level detection accuracyVSAvoidlubricant exposure to sensors
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent uses the magnetic indicator as an intermediary that allows sensors to detect lubricant levels indirectly through magnetic field interaction. The sensors remain isolated from direct lubricant contact while the magnetic indicator, which does contact the lubricant environment, transfers the level information magnetically, thus eliminating harmful exposure while maintaining measurement precision.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces direct mechanical/electrical contact sensing with magnetic field-based sensing. This substitution allows the sensors to remain isolated from the lubricant environment while still achieving accurate level detection through non-contact magnetic field interaction with the magnetic indicator.

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

3Measurement precision

If a simple float mechanism is used, then the device complexity is reduced, but the measurement precision and reliability are insufficient

Engineering Contradiction:
Improvelubricant level measurement accuracyVSAvoidsensing mechanism complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces simple mechanical float mechanisms with a magnetic sensing system. The magnetic indicator and sensor array provide more precise level detection compared to traditional floats, using magnetic field interaction rather than mechanical buoyancy, thereby improving measurement precision while keeping the overall structure relatively simple.

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

Solution Approach 2:

The magnetic indicator serves as an intermediary that enables precise level measurement without complex mechanical structures. By using magnetic field interaction, the system achieves high measurement precision with a simpler configuration than traditional mechanical level sensing mechanisms.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 system provides precise lubricant level monitoring, enabling efficient lubrication and preventing the lubricant pump from running dry, thus optimizing resource use and reducing maintenance costs.

Implementation Method 1

a magnetic indicator supported by the follower such that the magnetic indicator moves with the follower relative to the sensor tube and the fill tube, wherein the magnetic indicator is configured to trigger the plurality of sensors

Methodology Applied
Scientific EffectMagnetic field: Magnetic Field

Data Source

PatentEP4563871A1Integrated level sensor for lubricant pump assembly
Publication Date: 2025.06.04 GRACO MINNESTOA INC
  • EP4563871A1 patent drawingFigure 1
  • EP4563871A1 patent drawingFigure 2
  • EP4563871A1 patent drawingFigure 3A

AI summary

A lubrication pump assembly includes a fill tube and a sensor tube located within the fill tube. The sensor tube has a plurality of sensors disposed within the sensor tube and the sensors are configured to generate signals when triggered by a magnetic indicator, indicating a fill level of lubricant within the lubrication pump assembly. A follower within the lubrication pump assembly travels up and down within the lubrication pump assembly on a top of the lubricant. The fill tube is disposed between the sensor tube and the magnetic indicator.