Refrigerant Cycle Recovery for Faster Crushed-Ice Pasteurization Cooling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing freezing machines for making crushed-ice drinks take excessively long to cool the mixture from pasteurizing temperature to freezing temperature, exposing the mixture to bacterial loads during an intermediate temperature range of 25-30°C for a prolonged period.
Innovation Solution
The method involves a refrigerant cycle regulation system with a pasteurizing branch and a dual cooling branch system, allowing for rapid cooling to a intermediate temperature followed by slow cooling to the freezing temperature, utilizing solenoid valves and thermostatic valves to control refrigerant flow and reduce exposure to critical temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the refrigerant cycle is restored using the conventional single cooling mode, then the mixture is gradually cooled from pasteurizing temperature to freezing temperature, but the cooling time is excessively long and the mixture remains at critical temperatures (25-30°C) for a prolonged period exposing it to bacterial loads
Solution Approach 1:
The cooling process is segmented into two distinct phases: a rapid cooling phase that quickly reduces temperature from pasteurizing temperature to an intermediate temperature (reducing time at critical temperatures), followed by a slow cooling phase that gradually reaches the final freezing temperature (3-4°C) to ensure proper ice crystal formation. This segmentation resolves the contradiction by addressing both speed and quality requirements of the cooling process.
Solution Approach 2:
The refrigerant flow dynamics are made variable through the use of a variable expansion valve and dual cooling branches. The system dynamically adjusts the refrigerant flow rate and cooling intensity based on the current temperature stage, enabling rapid cooling when needed and slow cooling when quality control is critical. This dynamic control allows the system to minimize time at critical temperatures while ensuring proper freezing quality.
2Productivity
If the refrigerant flow rate is increased to speed up cooling, then the cooling time is reduced, but the ice crystal formation quality deteriorates
Solution Approach 1:
The cooling process is divided into two stages with different flow rates: rapid cooling stage with high refrigerant flow for speed, and slow cooling stage with reduced flow for quality. This segmentation allows the system to achieve both high productivity and high manufacturing precision at different phases of the same process.
Solution Approach 2:
The cooling process employs periodic variation in refrigerant flow intensity, alternating between high-intensity rapid cooling periods and low-intensity slow cooling periods. This periodic action enables the system to achieve overall fast cooling while ensuring proper ice crystal formation during the controlled slow cooling phases.
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 significantly reduces the time spent at critical temperatures, minimizing bacterial load exposure and efficiently forming crushed ice, with rapid cooling taking 50-70 minutes and slow cooling taking 60-120 minutes, thereby enhancing the production efficiency and safety of crushed-ice drinks.
Implementation Method 1
the mixture is gradually cooled by the coolant fluid passing through the evaporator
Implementation Method 2
a gas compression motor-driven compressor
Implementation Method 3
a condenser connected to the compressor delivery side
Implementation Method 4
an evaporator inside the refrigerant cylinder
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A method for pasteurising and restoring the refrigerant cycle in a freezing machine (1) for making crushed-ice drinks and the like comprises a pasteurising step during which a predetermined maximum temperature (T1) is reached and a step of restoring the refrigerant cycle, during which a predetermined freezing temperature (T3) is reached; the step of restoring the refrigerant cycle comprises a sub-step of rapid cooling of the pasteurising temperature with a first thermal excursion (ΔT') with passage from the temperature (T1) to a temperature (T2) and a sub-step of slow cooling from the temperature (T2) to the freezing temperature (T3) with a second thermal excursion (ΔT"), in which the first thermal excursion (ΔT') is greater than the second thermal excursion (ΔT").