Reasons for the Head Bearing of Jinan Air Compressor Need Overhaul螺杆主机需要大修的原因:
Reasons for overhaul of screw main engine:
With the running time of the air compressor, the main bearing will wear, which will increase the screw axial movement and radial displacement. This change will change the clearance between the screw and the screw, between the screw and the main body shell, and between the front and back end surfaces. These clearance changes are normal and permissible in the service life of bearings, and the resulting air compressor gas production attenuation and main motor load increase are normal and permissible.
However, with the unit running time gradually approaching the main engine overhaul cycle, the service life of the main engine bearing is gradually approaching the maximum allowable service life. At this time, the momentum of the axial and radial passages of the screw gradually approaches the maximum allowable value of the design, which will make the clearance between the screw and the screw, between the screw and the main body shell, and between the front and rear end faces change greatly. Although the mainframe can still run safely, it's time to schedule a major overhaul. When the unit runs longer than the overhaul period, the wear and fit clearance of the main engine bearing reach the limit permitted by the main engine technical conditions. At this time, the host is in an unsafe state, and the following serious consequences may occur at any time:
1. With the increase of the operating load of the main engine, the damage between the main motor and the main screw of the electrical system, and the strong friction between the front and back ends of the screw and the shell of the main engine, the operating load of the main engine will be greatly increased. In addition, the running load of the bearing with serious wear is also very large. In this way, the motor will be in an overload state, which will seriously endanger the safe operation of the motor. If the situation is serious, if the electrical protection device of the air compressor is not sensitive or fails, it may cause the motor to burn down.
2. Air compressor exhaust volume will be greatly attenuated.
The increase of the main engine clearance will lead to a serious reduction of the efficiency of the main engine, that is, the exhaust volume of the air compressor will have a greater attenuation, which will have a certain impact on the normal production of gas generating units. Especially for a small number of air compressor exhaust configuration users, due to attenuation, the gas compressor exhaust system is relatively stable, the pipeline network will reduce a large number of compressed air pressure, gas system equipment may not work or can not work properly, affecting the normal production of the device or causing temporary closure, resulting in losses.
3. The most serious consequence is that the master suddenly "embraces death".
Once this happens, if the response time of the electrical protection system is too long or the protection fails, it may also cause serious damage to the main motor and the electrical system.
On the one hand, maintenance costs will be much more expensive than normal reforms. On the other hand, because the components of the mainframe will be harmful, the comprehensive performance of the repaired mainframe will be better than that of the normal checking mainframe. But if the damage of the main engine is so serious that it has no maintenance value or can not be repaired at all, it can only be scrapped and replaced with a new main engine, and the direct loss is the greatest. Because the cost of newly purchased mainframe is usually about one third of the cost of purchasing the whole air compressor, which is much higher than the cost of maintenance of normal mainframe, and is very similar to the reform of limited comprehensive technical performance of mainframe and new mainframe under normal circumstances.
In summary, it can be seen that the normal overhaul of the main engine is not only the basic requirement of equipment maintenance, but also the basic requirement for enterprises to control the maintenance cost of normal equipment, avoid unnecessary capital losses and ensure the normal production of enterprises.
Therefore, it is not only necessary to overhaul the air compressor on time and according to the standard, but also necessary! The main engine of screw air compressor needs overhaul judgment:
Accurate, maintenance time should be based on the expiration of service life of main engine bearings, but in fact, it is difficult to have accurate indicators to judge whether the service life of bearings is about to expire or has expired. Therefore, according to the practice experience of nearly several hundred years, the international famous air compressor manufacturers determine that the standard is to run 20,000 hours of compressor, or to repair the main engine for four years.
In addition to the above criteria, based on experience, we can also make accurate judgments on the situation of the host country from the following aspects:
1) The sound of the main engine, especially the sound of the bearings; 2) the operating current of the motor, especially the difference between the no-load operating current and the standard value; 3) the vibration of the bearings in the nose.