The core principle of the vacuum fresh-keeping refrigerator is the dual action of "low temperature + vacuum (or low oxygen)". By actively removing oxygen from the storage space, it fundamentally inhibits the main factors leading to food spoilage, thereby achieving preservation effects far superior to those of traditional refrigerators.
Core Preservation Principles:
Traditional refrigerators primarily rely on low temperature to slow down microbial growth and the speed of chemical reactions. The vacuum fresh-keeping refrigerator adds the crucial measure of removing oxygen on this basis:
- Inhibiting Microbial Reproduction: Bacteria and molds that cause food spoilage are mostly aerobic. After vacuuming, the oxygen concentration drops sharply, greatly inhibiting or even halting the growth and reproduction of these microorganisms.
- Preventing Oxidative Deterioration: Discoloration, off-flavors, and nutrient loss (such as vitamin C, unsaturated fatty acids) in many foods (e.g., fruits, nuts, fatty meats) are caused by oxidation reactions. In a low-oxygen or oxygen-free environment, the rate of these chemical reactions is significantly reduced.
- Reducing Moisture Loss and Odor Transfer: The vacuum environment prevents moisture from flowing freely as vapor, so the food surface is less prone to drying out, better maintaining its original moisture content and taste. Odor molecules have difficulty diffusing in a vacuum, so different foods do not transfer smells between each other.
How Does the System Work?
A typical vacuum fresh-keeping refrigerator includes the following key components and processes:
- Airtight Storage Space: The refrigerator contains one or more independent, highly sealed drawers or compartments. Gaskets and latching mechanisms ensure their airtightness.
- Air Extraction and Vacuum Maintenance System: Core Component: A small diaphragm vacuum pump. Workflow: After the user closes the drawer, the system activates the vacuum pump to extract air (primarily oxygen) from the compartment, reaching a set low-pressure state. Maintaining Vacuum: The system is equipped with pressure sensors. When a pressure increase due to minor leakage is detected, it automatically activates the vacuum pump for replenishment pumping to maintain a stable low-pressure environment.
- Synergy with Low Temperature: The entire vacuum compartment remains in the refrigerator's low-temperature environment (typically the 0-4°C chilling zone or lower freezing zone). Low temperature further slows down the activity of anaerobic bacteria and all biochemical reactions, forming a dual guarantee with the vacuum environment.
The NIDEC 00H220R200 diaphragm pump is applied in vacuum fresh-keeping refrigerators from multiple brands. Its main parameters are:
- Operating Voltage: 12V / 24V
- Gas Flow Rate: 4.0 【L/min】 Min.
- Vacuum Degree: -75 【kPa】 Max.
- Weight: 370 grams
Considering that the diaphragm pump operates in an indoor environment, a quiet design is crucial. For the specific noise reduction solution of the diaphragm pump in the vacuum fresh-keeping refrigerator, please refer to the attached technical document.