The oil system is an important system of screw compressors and is also the main system of most mechanical equipment. In screw compressors, the main function of the oil circuit system is to supply lubrication to the compressor head. The oil circuit systems of screw compressors and piston compressors are different, although their functions are lubrication, their effects are different. Most piston engines use 19 # lubricating oil, which is not expensive and consumes a lot, as some of the oil is carried away by the compressed air. On the contrary, screw compressors use lubricating oil with a higher cost, usually around 80 #. Due to the use of a closed cycle oil supply system, the amount of oil carried away by the wind is negligible. Due to its self circulation system, the compressor lubricating oil is recycled and re lubricated during the lubrication process, allowing for repeated use with minimal loss. This effectively maximizes the effectiveness of the lubricating oil, and coupled with the higher grade of the lubricating oil used in screw compressors, the lubrication effect is naturally better. However, the oil circuit system of the screw compressor is not without faults, and oil leakage is one of the faults.

The oil circuit system of the screw compressor is tightly sealed, and under normal circumstances, there will be no oil leakage failure. However, oil leakage may occur when maintenance is not timely or accidents occur during operation. If there is less oil leakage, it may not cause significant losses. However, if there is more oil leakage, causing the compressor to shut down or wear due to oil shortage, it will not only cause losses to customers, but also serious damage to the compressor itself. Therefore, the oil leakage fault of the screw air compressor cannot be ignored.

It is not easy to detect oil leakage faults in screw compressors because screw compressors are generally enclosed in the casing structure, with mechanical parts inside the casing and the oil system naturally also inside the casing. During normal operation, the oil level of the screw compressor is also inside the casing, and daily inspections cannot observe any changes in the oil level. Even if the box cover is opened, the oil level window is not clear because the scale of the oil level is not accurate during operation, which can easily cause misjudgment of the oil level changes of the screw compressor.

There are many oil leakage points in screw compressors, and there is a possibility of oil leakage in any connected part of the entire oil system. There are various phenomena of oil leakage, one of which is oil leakage, which is very slow; One type is oil leakage, with a fast speed; Another type is fuel injection, which is almost instantly finished. Regardless of the type, discovering it requires a process. However, if encountering fuel injection faults, the machine will quickly shut down, and some may even cause serious damage to the compressor.

1、 Analysis of oil leakage reasons

As we mentioned earlier, there are three phenomena of oil leakage in the screw compressor oil circuit: oil leakage, oil dripping, and oil injection. The reason for oil leakage is simple - usually due to loose connections at the connecting parts, slight leakage may occur at weak points under certain pressure. If discovered in a timely manner and repaired properly, major malfunctions will not occur. But if the oil seeps for a long time, it can also lead to major disasters due to minor illnesses. Therefore, we cannot take it lightly. After discovering oil leakage, find a way to investigate the cause of the oil leakage. If there are other reasons, they should be promptly eliminated. Mild oil seepage is not easily detected, and sometimes on-site dust can cover up the oil seepage area, even if it does not cause further leakage in the long term.

The second situation, which is the phenomenon of oil dripping, is not easily detected in a timely manner because screw compressors have a box structure and are generally in a sealed state. Screw compressors are high noise equipment. When sealed with a casing, in addition to being aesthetically pleasing, they can mainly reduce certain levels of noise and minimize personal injury to operators. However, when operating in a sealed box, sometimes it is not possible to detect oil dripping from the screw compressor in a timely manner. Even if a part of the box door is opened, it is not easy to detect oil dripping in a timely manner because the light inside the box is dim in some corners, and by the time it can be detected, the oil dripping is already very large. Some of them flow to the outside of the computer case, which makes it easy for people to notice.

The phenomenon of oil leakage, such as oil leakage and dripping, in screw compressors is generally caused by loose connections or increased pressure. If the reason is so simple, it is enough to tighten the leakage point, but there should be other deep-seated reasons, which may lead to new hidden dangers and should be taken seriously. Speaking of fuel injection, the company where I work has recently experienced such a malfunction. A large amount of lubricating oil sprayed out, causing the screw compressor to shut down. The bottom plate of the chassis is full of oil. Some oil seeped out along the gaps at the bottom of the chassis. It was discovered in a timely manner and emergency shutdown did not cause greater damage to the equipment. However, starting the backup equipment required buffering time, which delayed half an hour. Although it was a normal phenomenon, it was bound to cause production losses. The cause of this malfunction is the blockage of the oil cooler of the screw compressor, which is a common fault of screw compressors. This phenomenon occurs in many screw compressors that have been running for more than three years, and in some cases, it can lead to early scrapping of the screw compressor. The main reason for the blockage of the oil cooler is the presence of impurities in the circulating water, which forms scale when encountering high temperatures, blocking the fine copper pipes of the oil cooler and preventing oil from passing through the oil cooler, resulting in this phenomenon.

2、 Handling of oil leakage

There are three types of oil leakage faults: oil leakage, oil dripping, and fuel injection, and different treatments should be made according to different phenomena for these three situations. In the case of oil leakage, if the cause is not caused by more complex factors of the equipment, but only by factors such as loose or poorly tightened connection parts or increased pressure, the connection parts can be tightened when the machine is shut down. In the case of oil dripping, the treatment method is basically the same as that of oil seepage, and the treatment method for oil seepage can be referred to. However, if there are underlying reasons, it is necessary to eliminate the hidden danger based on the underlying reasons before proceeding with the treatment. In the case of fuel injection, it is generally caused by the blockage of the oil cooler of the screw compressor. The main way to deal with this fault is to unblock the oil cooler. The method is to first take out the core of the oil cooler, place it in an iron tank, fill it with water, add descaling agent to the water, soak it for 1-3 days, and then take out the cooler core. Use soft copper wire to clear the scale in the cooler core one by one. While unclogging the cooler core, clean the entire oil circuit system. The method is to connect the oil system with pipe fittings to the cleaning pump truck, forming a self circulating system. The cleaning pump truck we use is an iron box that is more than one meter square, equipped with pushable small car wheels that can move the box freely and push it to the front of the compressor when in use. Equipped with a pressurized water pump and an electric heater, the descaling agent is poured into the water in the iron tank. The water pump is started, and the descaling agent begins to circulate in the oil system. After 1-3 days of soaking, the dirt in the oil system is cleaned.

3、 Inspection of oil leakage faults

During the inspection process, attention should be paid to the oil leakage fault of screw compressors. Firstly, the oil level inspection. The oil level window of screw compressors is designed differently by each manufacturer, and there are generally more types of them, such as the vernier tube type and the circular rotating window type. Regardless of which type, it is difficult to observe. Because the oil level fluctuates during the operation of the compressor. At this point, it is necessary to use tools such as flashlights to observe carefully. Check if there is a shortage of oil in the oil level. If the oil level drops in a short period of time, check if there is any oil leakage. The second is to inspect the oil circuit system for oil leakage and dripping. The third is to check the oil temperature. The number of oil temperature is displayed in the control panel and is generally not displayed on the homepage. During the inspection process, the oil temperature value should be flipped out to see if it exceeds the standard, that is, to see if it has been approaching a high temperature state for a long time. If it has been approaching a high temperature state for a long time, it is important to be careful of the increased possibility of oil leakage in the oil system.

In short, oil leakage in screw compressors is a common fault that poses certain risks to the compressor and should be taken seriously. In addition to regular inspections, regular maintenance and upkeep should also be carried out, and the three filters should be replaced according to the maintenance period of the screw compressor. For daily alarm prompts, a certain level of attention should be given and long-term work with illness should not be carried out. At the same time, it is necessary to regularly unblock the cooler core and prepare spare parts to ensure the normal operation of the screw compressor.