Weighing Cell Temperature Control via Gas Flow
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Solution Overview
Problem
Existing load cell systems in the pharmaceutical industry face challenges with cleanability and temperature control, as they are prone to damage from high temperatures and experience delayed temperature stabilization, leading to deviations in weighing specifications.
Innovation Solution
The implementation of an air inlet and outlet system within the load cell housing allows for direct temperature control using temperature-controlled gas, monitored by sensors, enabling faster reaction times and preventing particle ingress through regulated gas flow and overpressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If indirect temperature control via the receiving structure is used, then the housing is protected from direct thermal exposure, but the temperature control response time is delayed
Solution Approach 1:
The patent divides the temperature control function into two independent parts: indirect control via the receiving structure for thermal protection, and direct control via gas flow through the housing for rapid response. This segmentation allows each subsystem to optimize for its specific function without compromise.
Solution Approach 2:
The patent introduces temperature-controlled gas as an intermediary medium that directly contacts the housing interior to transfer thermal energy rapidly. This gas mediator enables fast temperature adjustment without requiring direct thermal contact between the heating/cooling device and the housing structure.
2Temperature
If air currents are introduced for temperature control, then faster temperature response is achieved, but particle ingress and contamination risk increase
Solution Approach 1:
The patent uses filtered or tempered gas that creates a controlled atmosphere within the housing. This inert or purified gas environment prevents contamination while enabling rapid temperature control, as the gas can be circulated quickly without introducing harmful particles or moisture.
Solution Approach 2:
The patent employs pneumatic principles by using controlled gas flow through the housing to achieve temperature regulation. The gas flow rate and pressure are regulated to maintain protective overpressure while enabling fast thermal response, demonstrating the application of fluid dynamics for dual purposes of temperature control and contamination prevention.
3Measurement precision
If the housing is kept free of air currents for accurate weighing, then measurement stability is maintained, but temperature control efficiency is reduced
Solution Approach 1:
The patent performs preliminary temperature stabilization using direct gas flow before initiating weighing measurements. The system first adjusts the housing temperature to the target value using rapid gas circulation, then maintains stable conditions during weighing, separating the temperature adjustment phase from the measurement phase to ensure both speed and accuracy.
Solution Approach 2:
The patent implements periodic temperature control cycles where gas flow is activated during temperature adjustment phases and reduced or stabilized during weighing phases. This periodic operation allows the system to achieve fast temperature response when needed while maintaining measurement stability during critical weighing operations.
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
This approach allows for quicker resumption of measurement processes after cleaning, maintains measurement accuracy, and prevents contamination by ensuring reliable gas flow regulation and correction for weighing values, while preventing the entry of particles and liquids into the housing.
Implementation Method 1
passing tempering and in particular cooled gas through the housing of the load cell
Implementation Method 2
first temperature sensor for monitoring the exhaust air temperature is arranged adjacent to the air outlet in the housing
Implementation Method 3
A second sensor with thermal contact is arranged on the weighing system to monitor the weighing system temperature
Implementation Method 4
any offset that occurs in the weighing value can be taken into account by correction values if necessary. As a result, the ingress of particles into the housing can be reliably prevented, particularly in the case of a certain overpressure
Data Source
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AI summary
The invention relates to a weighing cell (1) comprising a weighing system (4) arranged in a housing (3), a load cell (2) disposed outside the housing (3) and connected to the weighing system (4) via a supporting axis (6), and at least one temperature sensor (11), wherein an air inlet (8) leading into the housing (3) and an air outlet (9) leading out of the housing are provided, by means of which a gas can be guided through the housing (3). The invention also relates to a method for thermal control of a weighing cell, particularly in conjunction with a cleaning process, comprising a weighing system (4) arranged in a housing (3), a load cell (2) disposed outside the housing (3) and connected to the weighing system (4) via a supporting axis (6), and at least one temperature sensor (11), wherein a thermally controlling gas is guided through the housing (3) as a function of the temperature measured on the at least one temperature sensor (11, 12).