Flash Tank Refrigerant Charge Evaluation Without Circuit Drainage

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Current methods for evaluating refrigerant charge in refrigeration circuits are laborious, time-consuming, and often inaccurate, requiring significant operative intervention or visual estimation, which can be difficult and unreliable, especially in transport refrigeration units.

Innovation Solution

A method that measures and compares the quantity of liquid refrigerant in a flash tank to an expected quantity, calculated based on ambient temperature, allowing for instantaneous evaluation of refrigerant charge without draining the circuit or relying on sight glasses, and includes a pre-expansion valve to ensure accurate measurement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the refrigeration circuit is drained to measure total refrigerant quantity, then accurate measurement of refrigerant charge is achieved, but significant loss of time and productivity occurs

Engineering Contradiction:
Improverefrigerant charge measurement accuracyVSAvoidtime required for drainage and measurement
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The invention extracts the measurement function from the entire refrigeration circuit and concentrates it on a specific component (the flash tank). By measuring only the liquid refrigerant quantity in the flash tank and using this as a proxy for total circuit charge, the system avoids the time-consuming process of draining the entire circuit while maintaining measurement accuracy.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention creates a simplified model by measuring a representative sample (liquid refrigerant in flash tank) that correlates to the total refrigerant charge in the circuit. This copy/representation allows instantaneous evaluation without processing the entire system.

Inventive Principle:
Principle #26Copying

2Ease of operation

If a sight glass is used to estimate refrigerant charge level, then ease of operation is improved, but measurement precision deteriorates due to reliance on visual estimation

Engineering Contradiction:
Improvesimplicity of refrigerant charge evaluationVSAvoidaccuracy of refrigerant charge determination
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The invention replaces the mechanical/visual estimation method (sight glass) with an electronic measurement and calculation system. A processor measures parameters (such as pressure, temperature, or level in flash tank) and calculates the refrigerant charge quantity, providing both ease of operation and precise measurement.

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

Solution Approach 2:

The system performs self-evaluation by automatically measuring and calculating refrigerant charge levels without requiring operative intervention or visual estimation. The processor continuously monitors and determines charge status independently.

Inventive Principle:
Principle #25Self-service

3Measurement precision

If refrigerant charge evaluation requires operative intervention and draining, then manufacturing precision of measurement is improved, but device complexity and ease of operation worsen

Engineering Contradiction:
Improveaccuracy of refrigerant charge measurementVSAvoidcomplexity of measurement procedure
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The refrigeration circuit system performs self-diagnosis by automatically measuring and evaluating its own refrigerant charge status. The processor monitors system parameters and determines charge levels without requiring external operative intervention, simplifying the procedure while maintaining accuracy.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system implements continuous feedback by monitoring refrigerant charge levels and providing real-time evaluation. The processor uses measured data to determine charge status and can trigger alerts or control actions based on the evaluation, creating a closed-loop system that simplifies operation.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP4332467A1A method of evaluating refrigerant charge within a refrigeration circuit
Publication Date: 2024.03.06 CARRIER CORP
  • EP4332467A1 patent drawingFigure 1
  • EP4332467A1 patent drawingFigure 2
  • EP4332467A1 patent drawingFigure 3

AI summary

A method of evaluating refrigerant charge within a refrigeration circuit (1). The method comprises: measuring a quantity of liquid refrigerant within a flash tank (9) of the refrigeration circuit; determining an expected quantity of liquid refrigerant within the flash tank (9); comparing the expected quantity with the measured quantity of liquid refrigerant within the flash tank (9); and evaluating the refrigerant charge within the refrigeration circuit (1) based on the comparison. By virtue of this method, the refrigerant charge in the refrigeration circuit (1) can be evaluated quickly and reliably without significant operative intervention