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Compressor air end overhaul (or air end rebearing) is an extremely specialised compressor repair task that requires advanced skill and precision. CDH Group is one of the only organisations in the UK with the engineering expertise to offer a professional air end overhaul service for all makes of rotary vane, scroll, screw and piston air ends and motors.
What is an air end?
The air end is the beating heart of every compressor, where ambient air is compressed. The air passing through female and male helical rotors is compressed to the required bar using external forces. Radial and axial bearings, gaskets and seals all play an important role in ensuring the compressor works effectively and efficiently.
The importance of regular maintenance
Regular maintenance will optimise a compressor’s running hours, often extending its lifespan and ultimately saving your business money. All equipment will require an air end overhaul or rebearing, dependent upon total running hours. This will ensure operational reliability and prevent catastrophic failure.
Why do compressor components become damaged?
Over time, and dependent upon hours run, bearings and seals are subject to wear and tear. Where play occurs, damage can be caused. The more out of specification the air end becomes, the less efficient the entire process. Where seals are not maintained, contamination is possible, accelerating the process.
Compressors often operate 24 hours a day, seven days a week. Maintenance requirements are usually based on total running hours.
The requirement for total air end overhaul may be indicated by hours run. It may also become evident during routine maintenance checks or when efficiency levels drop.
The cost-benefit of air end repair over a complete system overhaul
The cost of an air end overhaul is typically less than a third of the projected cost of catastrophic failure. Once overhauled, the compressor’s projected lifespan is significantly extended. This makes preventative maintenance the best solution for reducing cost and keeping downtime to a minimum.
CDH Group repair and servicing
CDH Group service engineers begin by removing the air end and shipping it to the Group’s specialist repair centre. Here, the unit will be stripped down using purpose-designed pressers and pullers for extracting the bearings.
Where the air end remains serviceable, and the issues have been caused primarily by bearing or oil seal failure, CDH engineers identify the required remedial action and submit a condition report.
The entire unit is thoroughly cleaned and reconditioned using specialised heated wash machines. Replacement bearings and seals are identified and sourced. This is usually from extensive in-house stockholding, matching most types of compressors, including oil-free and rotary compressors.
Purpose-designed air end rebuild workshops
The engineering team then rebuild the air end, using new bearings and oil seals. Bearing are heated to a specific temperature to ensure a correct fit. CDH Group’s purpose-designed overhaul workshops are equipped with lifting gantries and other appropriate machine handling equipment to optimise operational safety and equipment security.
When problems are identified with compressors in use, diagnostic vibration monitoring techniques may be used to assess their condition. Timely vibration monitoring can reduce the incidence of compressor failure and costly downtime.
Diagnostic services
When problems are identified with compressors in use, diagnostic vibration monitoring techniques may be used to assess their condition. Timely vibration monitoring can reduce the incidence of compressor failure and costly downtime.
Air end exchange service
For critical equipment, CDH Group can offer a service exchange for applications where downtime is a more serious operational issue.
Here, engineers attend on-site to remove the compressor and replace it with an alternative unit for the specified duty. This will enable processes to continue until the air end overhaul is complete and the original unit can be recommissioned.
FAQs
An air end overhaul is a complete refurbishment of the compressor air end assembly. The process typically includes inspection, dismantling, cleaning, replacement of worn bearings and seals, reassembly and performance testing to restore efficiency and reliability.
Common signs include increased noise levels, vibration, higher operating temperatures, reduced air output, excessive oil carryover and rising energy consumption. Early diagnosis can help prevent costly compressor failures.
Rebearing involves replacing worn bearings within the air end. Bearings are critical components that support the rotors and maintain correct tolerances. Replacing worn bearings can extend the life of the air end and help avoid catastrophic failures.
In many cases, overhauling the air end is significantly more cost-effective than replacing the entire compressor. A professional assessment can determine whether refurbishment offers the best return on investment for your equipment.
The turnaround time depends on the compressor make, model, and air-end condition. Many overhauls can be completed within a few working days, helping to minimise production downtime.
CDH Group can overhaul and repair air ends from most leading compressor manufacturers. The service covers a wide range of rotary screw compressor air ends, subject to inspection and parts availability.
With correct servicing and maintenance, a rotary screw compressor air end can often operate for 40,000 to 80,000 hours or more before requiring a major overhaul. Operating conditions, maintenance quality and loading patterns all influence lifespan.