Dryer Sampling Apparatus for Explosive Environments
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Solution Overview
Problem
Existing sampling apparatuses are not suited for use in explosive environments, as they do not meet safety requirements for explosive atmospheres and cannot effectively monitor the risk of fires or explosions in dryers processing flammable powders.
Innovation Solution
A dryer with a sampling apparatus that includes a displaceable arm with a sample container, capable of inserting into a first zone within the dryer for collecting samples and then retracting to a second zone outside the product stream, equipped with an interface such as an air knife to prevent fire spread and devices for monitoring and adjusting pressure to prevent dust entry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a sampling apparatus is placed directly into the product stream to collect samples, then sampling efficiency is improved, but the risk of fire or explosion increases due to contact with flammable particles in explosive atmosphere
Solution Approach 1:
The sampling apparatus is divided into two separate zones: a first zone that contacts the product stream for sampling, and a second zone containing the sampling container and analysis equipment. This segmentation allows the sampling function to be separated from the potentially explosive environment, enabling efficient sampling while protecting the main apparatus from fire or explosion risks.
Solution Approach 2:
A displaceable arm acts as an intermediary mechanism, transferring the sampling container between the first zone (product stream contact) and the second zone (safe zone). This intermediary allows the container to be exposed to the explosive atmosphere only when necessary for sampling, while the main apparatus remains protected, thus maintaining sampling efficiency without continuously exposing the system to fire or explosion risks.
2Loss of time
If a sampling container is continuously exposed to the product stream for real-time monitoring, then measurement speed is improved, but safety requirements for explosive atmospheres are violated
Solution Approach 1:
The sampling container is periodically inserted into the product stream via the displaceable arm to collect samples, then retracted to the second zone for analysis. This periodic action enables real-time monitoring capability while ensuring the container is exposed to the explosive atmosphere only during brief sampling intervals, not continuously, thus maintaining both measurement speed and safety compliance with ATEX/IECEx standards.
3Reliability
If the sampling apparatus is designed with explosion protection zones and pressure monitoring devices, then safety in explosive environments is improved, but device complexity increases
Solution Approach 1:
The apparatus is segmented into a first zone for sampling contact and a second zone for safe container storage and analysis, separated by a boundary that allows the displaceable arm to pass through. This segmentation provides explosion protection by creating distinct zones with different safety requirements, while the modular design keeps individual zone components relatively simple, balancing safety improvement with manageable complexity.
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 apparatus allows for safe sampling in explosive environments, enabling the monitoring of physical and chemical characteristics of particles, such as density and moisture content, and providing an alarm system to prevent fires, thus enhancing the safety and efficiency of the drying process.
Implementation Method 1
an air knife provided with compressed air from an air inlet tube
Implementation Method 2
devices for monitoring and adjusting the pressure in the second zone to a higher pressure than the pressure in the first zone
Data Source
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AI summary
The invention relates to a sampling apparatus for use in explosive environ- ments comprising particles of a mean size of up to 500µm, the sampling ap- paratus comprising a displaceable arm having a sample container, which dis- placeable arm has a first position where the sample container is inserted into a first zone for collecting asample of particles into the sample container, and a second zone where the displaceable arm is outside the product stream, the second zone being contained in a housing with an opening for the displace- able arm. The sampling apparatus has an interface between the first and the second zone, which interface is selected from the list consisting of a closable member, a gate valve or an air knife. The invention also relates to a dryer comprising a drying chamber and a sampling apparatus of the invention. In a further aspect the invention relates to a method of estimating the flowability of a sample of organic particles.