[Mechanical Equipment Technology Edition] Daily Question 201709014: Refrigerator Maintenance
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This post was last edited by YORK Industrial Refrigeration on 2017-9-16 at 09:05. Starting from now, in order to enhance communication among users, a \"Question of the Day\" activity has been launched on the Mechanical Equipment Technology forum. We hope everyone will participate actively to progress and improve together! ! ! Rewards: 3 wealth for active participation, 10-15 wealth for accurate answers. This question is valid for two days; no scoring will be given after that. Question: For the refrigeration oil in refrigeration compressors, samples are taken for inspection during maintenance. What methods are generally used to check the quality of the oil? Answer: Chemical analysis methods, used to detect the presence of rust, dust, harmful acidic substances, corrosive water, other corrosive products, and metal particles. ================================ Promotion activities: Petrochemical sector – “Creative Ideas for Energy Savings” campaign (the second phase is currently in progress). http://bbs.hcbbs.com/thread-1666758-1-1.html (Source: Haichuan Chemical Industry Forum) 2017 Coal Chemical Industry – “My Technical Upgrades”. http://bbs.hcbbs.com/thread-1786290-1-1.html (Source: Haichuan Chemical Industry Forum)
For testing, a sample of the refrigerant oil can be dropped onto white absorbent paper using a dropper: (a) If the stain is light in color and uniform, then the quality of the oil is acceptable; (b) If the stain appears as concentric circles, it indicates that the oil contains impurities; (c) If the stain appears as faded spots, then the oil has deteriorated and cannot be used.
Starting with an external inspection, no obvious changes were observed; the analysts then analyzed the quality of the oil
1. Close the high-pressure exhaust and low-pressure suction shut-off valves, and use the process valve needle on the compressor to release the refrigerant inside the compressor, thereby allowing the compressor’s crankcase to be in communication with the atmosphere. 2. Unscrew the oil drain plug located at the bottom of the crankcase, drain all the refrigeration oil from it, and remove the filter screen for cleaning. 3. Nitrogen can be blown in through the low-pressure charging valve needle; block the oil drain port with your hand to increase the pressure inside the compressor, which helps to remove any remaining oil. After cleaning, dry the filter screen and reinstall it inside the compressor, then tighten the oil drain plug.
Check the oil level, as well as whether the oil has changed color or deteriorated
After long-term use, the quality of the lubricating oil (refrigerant oil) deteriorates, with an increase in impurities and moisture within the oil; therefore, it is necessary to regularly monitor and check the quality of the oil. Check whether the oil is clear and transparent, and verify whether the oil filter is clean.
Visual method, filtration method, analysis method.
The standards for refrigeration oil are a sufficiently low freezing point, a gentle viscosity-temperature curve, and good antioxidant properties. Based on this, it is necessary to regularly test the lubricating oil of the freezer. 1. Visual inspection. The main things to check are whether there are too many impurities in the refrigeration oil and whether it contains a high amount of moisture; 2. Smell it. Sniff the refrigerant oil with your nose to check for any unusual odor. 3. Touch with your hand. Coat your hand with the refrigeration oil to check whether it sticks to the hand and whether it has a certain level of adhesion. Of course, for more in-depth testing, advanced equipment is required.