Wireless Multipoint Probe Sensing for Freeze-Drying Process Control

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Solution Overview

Problem

Existing freeze drying systems face challenges in accurately monitoring temperature and residual moisture during the process due to the use of multiple wired thermocouples and destructive testing methods, which are cumbersome and time-consuming, leading to potential errors and disruptions in maintaining controlled aseptic conditions.

Innovation Solution

The implementation of a product condition measurement unit with a single elongate probe equipped with multiple closely spaced sensors for temperature and humidity monitoring, using wireless digital communications to transmit data for real-time control, allowing for precise measurement of temperature and humidity profiles within the freeze drying chamber without disrupting the process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If multiple wired thermocouples are used for temperature monitoring, then measurement coverage is improved, but device complexity and ease of operation deteriorate due to cumbersome wiring and installation

Engineering Contradiction:

Improvetemperature monitoring accuracyVSAvoidwiring complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces wired thermocouples with wireless sensor nodes that communicate via radio frequency. Each sensor node contains a microcontroller, temperature sensor, humidity sensor, and wireless transceiver, eliminating the need for physical wiring through the vacuum seal while maintaining measurement capabilities.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The monitoring system is divided into multiple independent sensor nodes distributed throughout the vacuum chamber. Each node independently measures local conditions and transmits data wirelessly, allowing comprehensive spatial coverage without requiring a centralized wiring system.

Inventive Principle:

Principle #1Segmentation

2Measurement precision

If destructive testing methods are used for residual moisture measurement, then measurement accuracy is improved, but productivity deteriorates due to time-consuming processes and sample destruction

Engineering Contradiction:

Improveresidual moisture measurement accuracyVSAvoidprocess efficiency

Core Design Contradiction:

Measurement precisionVSProductivity

Solution Approach 1:

The sensor nodes continuously monitor temperature and humidity conditions throughout the freeze-drying process, providing real-time data on product moisture content without requiring separate destructive testing. The system uses the existing process environment to gather measurement data.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

Instead of intermittent destructive sampling, the wireless sensor network provides continuous monitoring of product conditions throughout the freeze-drying cycle, enabling real-time process optimization and eliminating the need for time-consuming post-process destructive testing.

Inventive Principle:

Principle #20Continuity of useful action

3Measurement precision

If separate sensors are used for temperature and humidity measurement, then measurement capability is improved, but device complexity increases due to multiple components

Engineering Contradiction:

Improveenvironmental parameter monitoringVSAvoidsensor system complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

Each wireless sensor node integrates both temperature and humidity sensing capabilities into a single unit. The sensor node contains a microcontroller that reads both temperature and humidity sensors, combines the data, and transmits it via wireless communication, reducing the number of separate components needed.

Inventive Principle:

Principle #5Merging (Combining)

4Measurement precision

If wired sensors are installed in the vacuum chamber, then measurement capability is improved, but ease of operation deteriorates due to disruptions in maintaining aseptic conditions

Engineering Contradiction:

Improveprocess monitoring capabilityVSAvoidaseptic condition maintenance

Core Design Contradiction:

Measurement precisionVSEase of operation

Solution Approach 1:

The patent replaces physical wired connections with wireless radio frequency communication. The vacuum seal integrity is maintained because no physical penetrations are required, while sensor data is transmitted wirelessly from nodes positioned inside the vacuum chamber to receivers outside.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS11762403B2Process monitoring and control using battery-free multipoint wireless product condition sensing

Publication Date: 2023.09.19 IMA LIFE NORTH AMERICA INC

AI summary

An arrangement for monitoring an aseptic manufacturing process includes product condition sensors capable of making closely spaced measurements of a product condition such as temperature or humidity. The measurements are made using closely spaced sensors arranged in a linear array on a single probe, which may be used to take measurements at multiple levels within the product. Data from the sensors is transmitted to a data collection point via short range wireless digital communications. The sensors may be used to measure temperature and humidity at a single point. For example, when the sensors are used in pharmaceutical freeze drying, the location of a sublimation front may be calculated for each vial, and the freeze drying process may be controlled using the data.