Liquid nitrogen dispensing head
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Solution Overview
Problem
Existing methods for cooling concrete aggregates using liquid nitrogen face challenges such as limited cooling effect due to ice substitution, damage to conveyor components from extreme cold, and difficulty in distributing liquid nitrogen evenly and effectively on aggregate belts.
Innovation Solution
A liquid nitrogen dispensing head with a reservoir and distribution chambers separated by baffles, which directs liquid nitrogen through output ports onto the aggregate, creating a cooling tunnel to enhance penetration and retention, while adjustable features mitigate pressure and prevent aggregate blow-off.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If liquid nitrogen is dispensed directly onto aggregate on a conveyor belt, then cooling effect is achieved, but aggregate is blasted off the belt and conveyor components are damaged due to extreme cold temperatures
Solution Approach 1:
The dispensing head is segmented into multiple distribution chambers (first chamber, second chamber, third chamber) that sequentially cool the aggregate. Each chamber operates at different stages of the cooling process, allowing gradual temperature reduction rather than direct extreme cold exposure, thereby preventing aggregate blow-off while maintaining conveyor component integrity
Solution Approach 2:
The patent introduces intermediate cooling zones with insulating barriers between the liquid nitrogen source and the aggregate. These intermediaries (including insulated walls and spaced distribution chambers) mediate the thermal transfer, reducing the intensity of cold exposure to prevent damage to conveyor components while still achieving effective aggregate cooling
2Productivity
If liquid nitrogen is dispensed at high pressure to achieve rapid cooling, then cooling efficiency is improved, but aggregate is blasted off the belt
Solution Approach 1:
The cooling process is divided into multiple sequential chambers where pressure is gradually reduced. The first chamber handles high-pressure initial cooling, while subsequent chambers operate at lower pressures, allowing the aggregate to be cooled efficiently without being blasted off the belt
Solution Approach 2:
The system dynamically adjusts pressure conditions through the sequential chambers, transitioning from high pressure at the first chamber to lower pressure in subsequent chambers. This dynamic pressure management enables rapid initial cooling followed by gentler cooling that maintains aggregate stability on the belt
3Temperature
If more liquid nitrogen is added to increase cooling effect, then temperature reduction is improved, but distribution uniformity becomes difficult to achieve
Solution Approach 1:
The liquid nitrogen distribution is segmented across multiple chambers, each with its own distribution ports. This segmentation allows the total nitrogen quantity to be distributed uniformly across different zones and stages, preventing localized over-cooling while achieving overall temperature reduction
Solution Approach 2:
Each distribution chamber is designed with specific port configurations and orientations tailored to its location in the cooling sequence. This local optimization ensures that each chamber contributes appropriately to uniform overall distribution, with earlier chambers handling higher流量的 and later chambers providing finishing cooling
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 solution provides uniform and effective cooling of concrete aggregates, reducing damage to conveyor components and ensuring proper concrete curing by optimizing liquid nitrogen distribution and penetration.
Implementation Method 1
Liquid nitrogen 'boils' almost instantly when exposed to warmer temperatures and the transition to gas at that temperature is accompanied by a large volume increase
Implementation Method 2
Liquid nitrogen has been used to cool the aggregate or the mixture in the truck
Data Source
AI summary
An apparatus, system, device, and the like, for a liquid nitrogen dispensing head that may be used in a system for cooling aggregate, such as may be found in a batch plant involved in producing concrete. The dispensing head is positioned over a conveyor belt that conveys aggregate to a mixing apparatus to produce concrete. The head dispenses liquid nitrogen onto the aggregate to cool the aggregate and may include interior chambers separated by one or more baffles. The chambers may reduce the pressure of the liquid nitrogen onto the aggregate in relation to the flow pressure of the liquid nitrogen entering the dispensing head. In another example, an assembly may include sidewalls that extend to the aggregate on either side of the head to form a cooling tunnel through which the aggregate is conveyed and is exposed to the liquid nitrogen being dispensed from the head.