Blood Product Freezer Event Logging for Temperature Stability

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Solution Overview

Problem

Freezers used for storing blood and blood products face temperature control issues due to ambient air introduction and moisture condensation when the door is opened, affecting refrigeration effectiveness.

Innovation Solution

A freezer with a temperature event log, a controller employing PID control, and a user interface that monitors and logs temperature, door status, and defrost operations, using a latch with an electrical switch to ensure accurate temperature control and data logging, while preventing door openings during defrost mode.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the door is opened to access the storage compartment, then the compartment is accessible for product retrieval or storage, but ambient air is introduced causing temperature increase and moisture condensation

Engineering Contradiction:

Improvedoor accessibilityVSAvoidstorage compartment temperature stability

Core Design Contradiction:

Ease of operationVSTemperature

Solution Approach 1:

The defrost system performs preliminary heating action on the evaporator coils before they become blocked by ice accumulation. The controller periodically activates the defrost heater to melt ice buildup, preventing the coils from becoming insulated by ice and maintaining their refrigeration efficiency without requiring door opening

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The temperature sensor continuously monitors the storage compartment temperature and provides feedback to the controller. The controller adjusts the refrigeration unit operation based on this feedback, and also monitors door opening events to compensate for temperature changes, maintaining temperature stability despite door access operations

Inventive Principle:

Principle #23Feedback

2Temperature

If the refrigeration unit operates continuously to maintain low temperature, then the storage compartment remains cold, but energy consumption increases

Engineering Contradiction:

Improvestorage compartment temperature controlVSAvoidrefrigeration unit energy consumption

Core Design Contradiction:

TemperatureVSUse of energy by moving object

Solution Approach 1:

The refrigeration unit operates in periodic cycles rather than continuously. The controller monitors temperature sensor feedback and activates the refrigeration unit only when the temperature rises above the desired set point, allowing the system to maintain temperature control while reducing energy consumption through intermittent operation

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The controller adjusts the refrigeration unit operating parameters based on real-time temperature conditions. When the storage compartment temperature approaches the target range, the refrigeration unit reduces its operation intensity or cycles off, dynamically adjusting energy consumption to match actual cooling requirements

Inventive Principle:

Principle #35Parameter changes

3Reliability

If the defrost system operates to remove ice buildup, then refrigeration efficiency is maintained, but the door should not be opened to prevent temperature fluctuations

Engineering Contradiction:

Improverefrigeration system reliabilityVSAvoiddoor opening restriction

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The controller acts as an intermediary between the defrost system and the door access operation. When the defrost system is activated, the controller detects this state and prevents door opening through the door switch mechanism, ensuring that users do not open the door during defrost operation to avoid temperature fluctuations that would compromise the defrosting process

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

Maintains precise temperature control and effective refrigeration by minimizing temperature fluctuations and moisture accumulation, ensuring the quality of stored blood products through real-time monitoring and logging.

Implementation Method 1

a refrigeration unit coupled to the cabinet and configured to cool the storage compartment

Methodology Applied

Scientific EffectRefrigeration: Cooling

Implementation Method 2

a temperature sensor coupled to the cabinet in the storage compartment, a controller electrically coupled to the temperature sensor and operable to receive signals from the temperature sensor

Methodology Applied

Scientific EffectTemperature sensing: Thermal Radiation

Implementation Method 3

The controller may employ a proportional-plus-integral-plus-derivative (PID) based control methodology in controlling the refrigeration unit

Methodology Applied

Scientific EffectPID control: Feedback

Data Source

PatentUS7617690B2Blood products freezer with event log

Publication Date: 2009.11.17 HELMER SCI LLC

AI summary

A freezer for the storage of blood plasma and other blood products includes a user interface device which permits a user to adjust operating parameters of the freezer. The user interface device is operable to display the current status of the freezer. A defrost icon is displayed when the freezer is in defrost mode. The user interface device a graphical representation of the temperature within the freezer over the previous twenty-four hours. The controller of the freezer stores temperature related events which can be displayed on the user interface device or downloaded to a remote computer.