Table Of Contents
Industrial disc centrifuge repair covers a range of services, from a minor bowl re-gasketing to a complete overhaul of the centrifuge. In this section, we describe the range of disc centrifuge repair and rebuild options available to customers.
Dolphin Centrifuge has the expertise and knowledge to service and repair Alfa Laval disc centrifuges. We have more than 50+ years of collective centrifuge rebuild experience.
Dolphin Centrifuge’s remanufacturing process brings new life to your old industrial centrifuge. We use an industry-leading centrifuge rebuild process based on OEM specifications.
Dolphin also carries 200+ industrial centrifuges in our inventory. These are ready for remanufacture and sale.
Read our detailed article on Industrial Centrifuges - Types, Applications, Cost, etc.
Periodic maintenance of the centrifuge bowl goes a long way towards the reliability and optimum performance of the centrifuge. This servicing is further divided into bowl service and centrifuge maintenance.
The specific centrifuge application defines the service interval of this minor service of the bowl. In other words, processing benign fluids such as lubricating oil could have a period of 3-6 months between minor bowl service.
The processing of aggressive chemicals or fluids with abrasive solids requires the bowl service to be performed every 2-3 weeks or sooner.
We recommend the centrifuge user frequently inspect the centrifuge during the initial startup phase to determine the condition of the bowl seals. Based on the condition of the bowl during these inspections, the user can decide the period between bowl servicing.
During the regular operation of the centrifuge, the seals and gaskets in the bowl are exposed to varying temperatures, process fluid, and sludge deposits. Over time this exposure deteriorates the seals and affects centrifuge performance.
A periodic bowl service that includes replacing all seals and gaskets in the bowl is essential to maintain centrifuge performance.
A bowl service involves changing the o-rings, oil seals, gaskets, and other consumable parts. The gaskets are lubricated with an exceptionally long-lasting lubricant specific for centrifuge seals. The seal grooves and other crevices also need to be cleaned thoroughly to remove accumulated sludge and other debris.
Cleaning the operating water system under the bowl body is an essential part of this periodic minor service. The primary purpose of cleaning this part of the system is to clean out sediment and mineral deposits that can prevent the operation of the sludge ejection mechanism.
A simple cleaning with vinegar or any mineral cleaning solvent is sufficient. The replacement of o-rings with the proper lubrication is also an essential part of the cleaning process.
Any nozzles in the operating water system are to be thoroughly cleaned and blown out with compressed air.
A major service of the centrifuge involves all the aspects of the minor service above. In addition to the consumable parts, this service includes replacing mechanical parts of the centrifuge transmission, including bearings, friction pads, springs, etc.
Industrial centrifuge manufacturers recommend a major overhaul of the disc centrifuge every 2-3 years. This period between the service is based on the expected lifespan of the components. The expected wear of specific components in the bowl also defines this period.
An unexpected failure of a transmission component could require a major centrifuge rebuild. For example, a sudden bearing failure could make the centrifuge inoperable. A major service is unavoidable under such circumstances.
A thorough cleaning of the stack bowl as part of the major service process involves cleaning the disc-stack and other components of the liquid passage. The distributor, cone, the upper chamber of the top disc are all areas that can accumulate sludge during operation.
The sediment can scratch the individual disc surface that the sludge particles stick.
An industrial parts washer or other mechanical cleaning equipment is well suited for the cleaning of these components. The soaking of the bowl discs in a mild detergent or special disc cleaner liquid removes the sludge buildup. Subsequent rinsing of the disc stack follows the soaking process.
As an added step, a worn disc stack may be electropolished to smoothen out the disc surface to resist the possibility of sludge particles sticking to the discs.
A major service of the disc centrifuge includes a transmission rebuild and the bowl cleaning mentioned above. This part of the service involves the replacement of all bearings and related parts. In a centrifuge with a friction clutch, the replacement of friction pads is also a part of the service. These parts replacements reduce the possibility of unexpected centrifuge breakdown during operations.
The inspection of the gears in the gear train is a crucial part of this service. Uneven wear of the gear teeth may require the gears to be changed. It is important to change the transmission gears as a complete set, not as individual gears. The image below shows a typical disc-centrifuge gear set.
If the centrifuge was experiencing high vibration levels before service, it requires replacing the vibration dampening spring in the spring casing.
While draining the gearbox oil, the operator should look for metal shavings in the oil. The presence of brass or steel metal particles in the oil implies excessive wear of the gear set. These metal particles damage the bearings through the splash lubrication. Therefore, replacement of all bearings and thorough cleaning of the gearbox is essential.
An old disc centrifuge that has been out of service for a prolonged period requires a complete overhaul or rebuild. Often the centrifuge is of unknown origin without any information regarding its previous use.
In such cases, a complete and thorough rebuild of the centrifuge is crucial for safe future operation.
Our centrifuge rebuild process is detailed and involves the following steps.
Testing the rebuilt centrifuge is essential to verify the machine’s functionality and overall mechanical status. The functionality refers to the fluid flow through the centrifuge and the operation of the self-cleaning bowl.
Leakproof operation of the inlet and outlet fluid pathways is the first step if the centrifuge system has external piping, pressure testing of the pipes a key step in the process.
The bowl opening and closing during the sludge ejection process is the second step of the testing process. This step involves monitoring the operating water pressure and flow to determine the parameters within the manufacturer’s specifications.
Depending on the centrifuge application, the testing could be with water or mineral oil.
The monitoring of the drive motor current draw indicates the health of the centrifuge gear train.
The cost of repairing an industrial centrifuge depends on the type of centrifuge and the extent of wear or damage that needs to be fixed.
The following table lists the typical costs to repair common centrifuges.
|↓ Type of Centrifuge||Minor Service||Major Service||Complete Rebuild|
|Small Disc Centrifuge (Manual Clean)||$800+||$2,000+||$5,000+|
|Medium Disc Centrifuge (Self-Clean)||$2,500+||$4,500+||$8,000+|
|Small Decanter Centrifuge (40 GPM)||$4,000+||$10,000+||$15,000+|
|Medium Decanter Centrifuge (80 GPM)||$6,500+||$13,000+||$18,000+|
The time for repair again depends on the size of the centrifuge and the type of repair. As an example a small disc centrifuge can be totally rebuilt in about 3 days whereas a large capacity self-cleaning disc centrifuge can take 4 weeks or more for a complete overhaul.
The processing of fluids with abrasive or metal particles has a detrimental effect on certain bowl components. The sliding piston is especially subject to wear and tear due to the separated solids continuous contact during the sludge ejection process.
The image below shows the typical damage seen on the sliding piston.
Minimal wear on the piston is fixable by local sanding of high spots.
Local pitting damage on parts exposed to operating water is often remedied by smoothening the surface with soft grinding. Excessive pitting beyond 0.2 mm requires the replacement of the affected parts.
Older centrifuge systems have timer-based sludge ejection systems that have limited functionality and are often the cause of excessive fluid losses and frequent centrifuge malfunctions.
A control system upgrade with PLC controllers and HMI (touchscreen) adds tremendous value and functionality. The cost of the upgrade is often minimal compared to the benefits.
Older, inefficient pumps are replaceable with controllable, heavy-duty pumps with accurate flow control through VFDs.
The up-gradation of a bare disc centrifuge into a complete functioning module with PLC controls with built-in alarms, troubleshooting, feed and discharge pumps, sludge collection, and handling systems, etc., adds decades of service life and additional functionality.
The following is a list of centrifuge upgrades often performed by Dolphin Centrifuge.
Centrifuge operators should keep certain centrifuge parts in the form of service kits in stock at all times. This stocking of kits reduces downtime related to service that can occur waiting for service parts.
The most common kit to stock is the bowl service kit. This set of parts is inexpensive and easy to store. You may order the service kit for your centrifuge from our centrifuge parts order page.
And lastly, periodic centrifuge maintenance using these kits reduces unplanned downtime that can have significant production losses with financial consequences.