Perforated Drum Cryogenic Cooling to Prevent Frost Clogging
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Solution Overview
Problem
Existing drum freezers for bulk food products face inefficiencies due to the need for regular removal of snow or ice, which clogs perforations and disrupts heat exchange, requiring pressurized gases like compressed air that can contaminate products and affect cryogen consumption.
Innovation Solution
An additional liquid cryogen ramp is positioned under the drum to direct cryogen towards the wall at the inlet zone, achieving a 'zero adhesion' condition and pre-cooling products, reducing adhesion and frost formation, and eliminating the need for compressed air by using cryogenic temperatures below -50°C.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If compressed air is used to unblock drum holes, then the drum holes are cleared of snow and ice, but the food product becomes contaminated with oil and humidity
Solution Approach 1:
The patent uses nitrogen gas instead of compressed air to unblock the drum holes. Nitrogen creates an inert atmosphere that prevents oxidation and contamination of the food product, eliminating the harmful effects of oil and humidity associated with compressed air while maintaining effective snow and ice removal from the drum holes.
2Reliability
If compressed air is used to unblock drum holes, then the drum holes are cleared, but cryogen consumption increases due to heat balance disruption
Solution Approach 1:
By using nitrogen gas at the same pressure as the cryogen supply, the system maintains thermal consistency and avoids the heat balance disruption caused by ambient temperature compressed air. This eliminates unnecessary cryogen consumption while effectively unblocking the drum holes.
3Reliability
If a buffer capacity and pressure different from cryogen supply are used, then unblocking can be performed, but the device complexity increases
Solution Approach 1:
The patent makes the nitrogen supply system multi-functional by using it for both product cooling and drum hole unblocking operations. The nitrogen is supplied at the same pressure as the cryogen, allowing a single pressure regulation system to serve both purposes without requiring separate buffer capacities or pressure control mechanisms.
4Productivity
If snow and ice accumulate on drum holes, then heat exchange efficiency decreases, but regular removal operations are required
Solution Approach 1:
The patent implements continuous nitrogen flow that simultaneously cools the products and prevents snow and ice accumulation on the drum holes. This continuous action eliminates the need for periodic unblocking operations, maintaining constant heat exchange efficiency without operational interruptions.
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 enhances operational efficiency by minimizing product adherence, reducing frost and ice buildup, and optimizing heat balance, while eliminating the use of compressed air, thus preventing contamination and reducing cryogen consumption.
Implementation Method 1
at least one ramp for projecting a liquid cryogen, additional ramp located inside the enclosure, opposite a portion of the outer wall of the drum located at the level of the inlet zone of the products in the drum
Implementation Method 2
directing liquid cryogen towards said wall portion of the drum and through this wall portion, via said perforations, towards the products admitted into the drum
Implementation Method 3
this ensures that the surface considered is brought to a sufficiently cold temperature (lower than a given limit temperature that we will explain later), so that the frost which will form on this surface sticks less
Implementation Method 4
the projection of a liquid cryogen from the outside towards the wall of the drum and through this wall
Data Source
Figure 1~2
Figure 3
AI summary
The invention relates to a device for cooling bulk products, such as a device comprising a drum rotatably mounted on the axis thereof, said drum containing perforations distributed on the cylindrical lateral wall thereof in whole or in part. Additionally, the device comprises a motor for driving said drum and a thermally insulated chamber of elongate form along the axis of said drum and enveloping said drum, and means (2) for cooling products, for example products for injecting a cryogenic fluid into said chamber. The invention is characterised by the implementation of the following measures: - the device additionally comprises at least one ramp (3) for projecting a liquid cryogen, an additional ramp located inside the chamber opposite a portion of the drum wall located in the area where products enter the drum, - this additional projection ramp is capable of directing the liquid cryogen to said portion of the drum wall and through this portion of the wall, via said perforations, to the products that enter the drum.