Gas Chromatograph Oven Cooling With a Sealed Refrigerant Circuit
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Solution Overview
Problem
Existing gas chromatographs face challenges with cooling systems that use liquid cooling media, such as nitrogen or carbon dioxide, which result in safety concerns, material stress due to sudden temperature changes, and coolant consumption, leading to increased costs and installation complexities.
Innovation Solution
A gas chromatograph design where the heat-absorbing side of the refrigeration machine is located inside the oven door, with the coolant circuit closed off from the furnace chamber, using a compression refrigeration system with a heat exchanger accessible from outside, allowing for efficient cooling without coolant residue in the furnace chamber and enabling easy retrofitting of existing systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If liquid cooling media (nitrogen or carbon dioxide) are used to cool the furnace chamber, then cooling efficiency is improved, but safety concerns and material stress due to sudden temperature changes occur
Solution Approach 1:
The patent introduces a heat exchanger as an intermediary device between the cooling system and the furnace chamber. The heat exchanger transfers heat from the furnace chamber to the cooling medium indirectly, avoiding direct contact between liquid nitrogen/carbon dioxide and the chamber. This resolves the contradiction by maintaining efficient cooling while eliminating safety hazards and thermal shock to materials.
Solution Approach 2:
The patent replaces the direct mechanical introduction of liquid cooling media into the furnace chamber with a thermal field-based heat exchanger system. Instead of mechanically injecting cold liquid that causes sudden temperature changes, the system uses controlled heat transfer through the heat exchanger, eliminating material stress while preserving cooling efficiency.
2Temperature
If liquid cooling media are used in the furnace chamber, then rapid cooling is achieved, but coolant consumption increases leading to cost increases
Solution Approach 1:
The patent implements a closed-loop cooling system where the cooling medium is continuously circulated through the heat exchanger and recovered for repeated use. Instead of consuming liquid nitrogen or carbon dioxide, the system recovers and reuses the cooling medium, eliminating coolant loss and associated costs while maintaining rapid cooling capability.
Solution Approach 2:
The patent establishes continuous circulation of the cooling medium through the heat exchanger, maintaining sustained cooling action without interruption or consumption. The cooling medium continuously absorbs heat from the furnace chamber and is repeatedly reused, eliminating the need for continuous replenishment and reducing operational costs.
3Temperature
If the heat-absorbing side of the refrigeration machine is placed inside the furnace chamber, then cooling efficiency is improved, but accessibility to the furnace chamber is reduced
Solution Approach 1:
The patent segments the refrigeration system into two distinct parts: the heat-absorbing heat exchanger component placed inside the furnace chamber for efficient cooling, and the coolant circuit components (compressor, condenser, expansion device) located outside. This segmentation allows the furnace chamber to be accessed and opened without interference from the cooling system components, while maintaining high cooling efficiency through the internally-placed heat exchanger.
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 configuration eliminates coolant loss, reduces material stress, enhances safety, and allows for rapid temperature control, enabling efficient and cost-effective cooling without the need for continuous coolant consumption, while maintaining easy access to the furnace chamber.
Implementation Method 1
the heat-absorbing side of the refrigeration machine is arranged in the furnace chamber
Implementation Method 2
a substance sample is fed into the separation column by means of the injector and then flows through the separation column with the carrier gas introduced via the carrier gas connection
Implementation Method 3
using a compression refrigeration system with a heat exchanger accessible from outside
Implementation Method 4
The furnace space can be heated by resistance heating
Data Source
AI summary
A gas chromatograph (1) is shown and described, comprising an oven (2), an oven door (3) providing access to the oven chamber (2), a separation column (4) arranged in the oven chamber for separating substances, a carrier gas connection, an injector (5) for feeding samples to the separation column (4), a connection (6) for a detector at the outlet of the separation column (4), a heating device for heating the oven chamber, and a cooling device (7) for cooling the oven chamber. A gas chromatograph with easily retrofitted and user-friendly cooling via a refrigerant circuit is implemented by the cooling device (7) being a refrigeration unit with a refrigerant circuit having a heat-absorbing side (8a) and a heat-dissipating side (8b), wherein the refrigerant circuit is sealed off from the oven chamber.