The causes of the air compressor head bearing overhaul and judgement

Screw air compressor host need to overhaul the reasons:

With the passage of air compressor running time, the host each bearing wear will inevitably occur, causing the screw to produce axial dynamic and radial displacement, the changes will make between screw and screw, the screw and the gap between before and after the host shell and end face change. The clearance between the bearing life period is normal, allowed, and the resulting air compressor gas production attenuation increases and the main motor load are also normal, allowed.

Overhaul period as the unit operation time close to the host, the host of the bearing life gradually becomes the maximum allowable limit. At this point the screw axial and radial momentum gradually becomes the maximum design allowable values, the changes will make the screw and screw, the screw and the host shell, and between before and after the clearance between the end face bigger change. The host running while still is safe, but have to plan to overhaul the host must be considered. Because once unit operation time across the overhaul period, bearing wear and host fit clearance to reach host technology conditions allow limit value, the host is in the midst of unsafe operation, serious consequences can occur at any time as follows:

1, host operation load increases, the harm of main motor and electrical system

Host between the screw, the screw and end face between before and after, screw and possible strong friction between the host shell makes host operation load has increased dramatically, the serious wear of bearing operating load is very big. As a result, the working state of the motor is in overload, will seriously threaten the safe operation of the machine. In severe cases, if the air compressor unit electrical protection device response is not sensitive or failure, may also lead to motor burn down.

2, air compressor displacement was substantial attenuation will happen.

Increasing host fit clearance efficiency can lead to serious, namely air compressor exhaust produced a significant attenuation, a certain impact on the normal production of gas units. Especially for the air compressor exhaust configuration rich small amount of users, due to attenuation, the air compressor exhaust gas in gas system under the condition of relatively stable, pipe network will reduce a lot of compressed air pressure, gas system equipment may appear can’t work or simply can’t work normally, which affect the normal production of unit or cause temporary shutdown, bring losses.

3, the most serious consequence is the host of a sudden "lock".

Once appear such circumstance, if failure, electrical protection system response time may also bring serious harm to the main motor and electrical system.

For host "lock" processing, on the one hand, overhaul maintenance cost will be more expensive than normal overhaul many, on the other hand, due to host components will have damage, so comprehensive performance after repair of the host will also host is less than the normal overhaul. If host injury severity has arrived and there is no fixed value or cannot repair, it can only be dispensed replaced the new host, direct loss is the biggest of all. Because the cost of the new host is usually buy about a third of the cost of air compressor unit, host overhaul cost is much higher than normal, and normal overhaul qualified comprehensive technical performance of the host and the new host is very similar!

In conclusion analysis shows, the normal host overhaul work is not only the basic requirements of equipment maintenance, but also control the normal equipment maintenance costs, avoid unnecessary losses, and guarantee the basic requirement of the enterprise’s normal production.

Host on time, therefore, the air compressor according to the standard overhaul is not only necessary, but it is also a must! Screw air compressor host needs into line overhaul decision:

Accurately, the overhaul time should be host to the service life of the bearing expiration shall prevail, but in fact it is difficult to have accurate indicator to judge whether the service life of bearing is about to expire or has expired, so the international famous air compressor manufacturers according to the nearly hundred years of practical experience to determine standard is in the compressor to run 20000 hours, or four years to overhaul the host.

In addition to the above standard, according to the experience from the following aspects of the host status to make more accurate judgment:

1) host the voice of the runtime, especially bearings have the same ring;

2) the motor running current, especially the difference of no-load running current and standard values;

3) the head of each bearing vibration.