A, in the screw compressor failure, exhaust with oil failure is the most common, causing exhaust with oil failure of the main factors are:
1. oil separation core damage
In the operation of the screw compressor, the oil separation core is damaged such as broken, perforated phenomenon, then it loses the role of oil and gas separation. That is, the mixed gas and compressor exhaust piping directly through, then a large amount of cooling oil is not separated out, will be discharged with the gas body, resulting in the exhaust process with oil failure.
2.oil return line failure
In the working process of the screw compressor, the oil return line shoulders an important responsibility, oil separation core internal and compressor inlet will form a pressure difference, in the role of this pressure difference, the oil return line is responsible for the oil separation core at the bottom of the gathered oil back to the compressor, in the next cycle process continue to use. If the oil return line is blocked, broken and incorrectly installed, it will not be able to transport the oil gathered at the bottom of the oil separation core back to the compressor, causing too much oil to accumulate at the bottom, then this part of the oil that has not been transported back to the compressor will be discharged with the gas, and there will be the phenomenon of oil in the exhaust process.
3. the system pressure control is too low
In the operation of the screw compressor, the system pressure control is too low, will cause the centrifugal force in the separator is less than the work required centrifugal force, then the role of the separator will not be fully reflected, it will cause the next link into the separator core gas oil content is too high, beyond its separation range, also led to the oil and gas separation is not complete, in the compressor exhaust process with oil failure.
4.the minimum pressure valve failure
In the operation of the screw compressor, the minimum pressure valve is to ensure that the operation of the system pressure control in the process of minimum pressure above. If the minimum pressure valve failure phenomenon, then the minimum pressure of the system will not be guaranteed, due to the luck of the equipment is very large gas consumption, it will cause the system pressure is too low, the oil return line can not return oil. The oil gathered in the bottom of the oil separator core will not be able to return to the compressor, will be discharged from the compressor with the compressed gas, resulting in the flat exhaust process with oil failure.
5.the compressor to join the cooling oil is too much
Before the operation of the screw compressor, adding too much cooling oil, more than the compressor range, then in the operation of the compressor, due to the oil level is too high, although the separation system to separate the oil and gas out, but in the discharge of gas, the gas will also be involved in the cooling oil to the gas discharge, resulting in the discharge of gas containing too much oil, with oil failure.
6.The quality of cooling oil is not qualified
Before the operation of the compressor, the addition of unqualified cooling oil, or cooling oil more than the applicable time, has been unable to achieve the effect of cooling. Then in the operation of the screw compressor, the cooling oil lost its role, and can not cool the oil and gas separation. Then in the exhaust process will certainly appear with oil failure.
Second, the fault check, troubleshooting steps
When the compressor is found with oil in the exhaust, do not have to blindly disassemble the equipment, but should be based on the above reasons for analysis, in accordance with the steps from easy to difficult to determine the parts of the fault. This can reduce a lot of repair time and manpower.
When the compressor starts normally and the system reaches the rated pressure, slowly open the exhaust gate valve, the opening should be as small as possible to allow a small amount of gas to escape. At this time, use a dry paper towel against the exhaust airflow, if the paper towel immediately discolored and oil droplets, you can determine the compressor exhaust with oil in excess of the standard. According to the amount of oil in the exhaust gas and different time periods, etc., the correct judgment can be made on the part where the fault occurs.
When the opening of the exhaust gate valve is increased, the discharge airflow is found to be uninterrupted thick mist, indicating that the airflow contains a lot of oil, and then check the oil return to the oil return tube observation mirror. If the oil return tube observation mirror oil return significantly increased, generally for the separator core broken or separator cooling oil added too much; if the oil return tube observation mirror no oil return, generally for the oil return tube broken, blocked.
When the exhaust gate valve to increase the opening, found that the front part of the discharge airflow is dense fog, after a period of time and normal; continue to increase the opening of the exhaust gate valve, all the exhaust valve open, then observe the system pressure gauge, if the pressure gauge shows that the pressure is lower than the minimum pressure valve set pressure, the exhaust valve continues to exhaust and the airflow is uninterrupted dense fog. This phenomenon occurs, the fault is generally the minimum pressure valve failure.
When the normal shutdown, automatic venting valve for exhaust, if the exhaust with a large amount of oil, indicating that the automatic venting valve is damaged.
Third, common failures to lift measures
Screw compressor in the operation of the exhaust with oil in the process of failure is a variety of reasons, different reasons require different measures to solve.
1.oil separation core damage problem
Oil separation core damage is a common phenomenon, so in the screw compressor before the operation of the equipment needs to be checked, in the use of the process should be in strict accordance with the operating procedures, after the use of regular maintenance of the equipment. Found that the oil separation core is broken and perforated phenomenon, should be replaced in a timely manner to ensure the normal operation of the equipment.
2.Problems in the oil return path
In the process of equipment operation, if you encounter a blockage in the oil return path, you need to check the pressure drop of the separator, such as pressure drop without problems need to clean the oil separator core, if the oil separator core is fractured must be replaced in a timely manner.
3.System pressure control too low problem
For the operator, should be familiar with the control pressure of the equipment, when the problem is found to reduce the load of the system, so that the system pressure to reach the rated working pressure to carry out.
4. the minimum pressure valve failure problem
In actual operation, if the minimum pressure valve is found to be invalid, then it must be replaced, and then work after the replacement is completed.
5.The problem of adding too much cooling oil to the compressor
When adding cooling oil to the compressor should first understand the theoretical value of how much cooling oil should be added to the equipment, the addition of cooling oil should be the responsibility of a person, and generally should be controlled below the middle of the sight glass.
6.Quality of cooling oil
For the addition of cooling oil should be added in strict accordance with the requirements of the equipment on the cooling oil, because the requirements of different equipment on the cooling oil is not the same. After adding, the time of adding should be recorded, and when the cooling oil reaches its service life, it should be changed out on time. The quality of the added cooling oil should be strictly controlled to eliminate the addition of unqualified cooling oil.
Fourth, troubleshooting and solution notes
In the process of troubleshooting there are several points that must be noted, otherwise the fault not only can not be eliminated, but may lead to greater consequences.
If it is judged to be a problem of the return pipe, the return pipe can be cleaned and blocked or re-welded. In the process should pay attention to: first of all, must ensure that the oil return pipe is smooth, not because of welding to make the inner diameter of the pipe smaller; secondly, the installation position of the oil return pipe must be correct, generally the bottom center of the separator core concave and the gap between the end of the oil return pipe in 3 ~ 4mm.
If it is judged that the separator core is the problem, only the new separator core can be replaced. In the process should pay attention to: firstly, to carefully check whether the new separator core is deformed and damaged; secondly, to do a clean job of cleaning the combination surface of the separator cylinder and the top cover; finally, the installation should check whether there are metal objects and other conductive bodies on the sealing paper pad at the top of the separator core, because the cooling oil rotates at high speed inside the separator, and a large amount of static electricity will be generated on the separator core.
If it is judged to be a problem of excessive separator oil level, it should be properly discharged. Check the separator oil level in the correct way, first of all, the unit must be parked level, if the unit tilt angle is too large, the oil level meter display in the separator is inaccurate; secondly, the inspection period is appropriate to choose before driving or after half an hour of shutdown.
Although the screw compressor is a highly reliable model, but it does not require no maintenance and maintenance. Must know that any equipment is “three points in the use, seven points in the maintenance”, therefore, whether the exhaust oil or other faults, should strengthen the operation of the maintenance work, the fault will be eliminated in the bud.
Post time: May-26-2023
