CASE STUDY
LIQUID RING VACUUM PUMP SHAFT REPAIR
In-situ shaft repair for coal mine vacuum pump
Industry: Mining
Application: Vacuum Pump Shaft Repair
Products: Belzona 1111, Belzona 9411
Customer Location: : QLD, Australia
Application Date: 2003
PROBLEM
A major Queensland Coal Mine contacted Rezitech regarding a bearing failure on a CHPP Liquid Ring Vacuum Pump.
Due to the fact Rezitech overhaul and supply new vacuum pumps throughout the mining industry we were contacted by the client and asked if we could offer a possible in-situ shaft repair method relating to a vacuum pump bearing failure.
Shaft showing extensive damage
The client then provided the required information regarding images and measurements of the extensive shaft damage which included significantly worn bearing journals, severely eroded bearing shoulders as well as a barely recognisable shaft fixing thread. A conventional repair method would require the vacuum pump be sent off-site so a replacement shaft could be manufactured and fitted. This would have meant a prolonged outage and significant financial losses for the client.
APPLICATION
Following consultation with the customer, it was decided to use Belzona repair composites to mould and restore the bearing journal, bearing shoulder, and seal areas in position without removing the vacuum pump.
Working with the bearing manufacturer, we confirmed all critical tolerances and sizing, allowing us to design and fabricate a precision shaft former to the original shaft specifications. Because the selected Belzona product exhibits no shrinkage, the former was manufactured to the exact dimensions to suit the final bearing fitment. We then manufactured a tool to hold the bearing in position while cooling. In addition, we manufactured a fixing ring to replace the non existent shaft nut.
Shaft former made to the exact specifications of the original shaft
Firstly the damaged shaft area was thoroughly cleaned to remove any contamination. This section of the shaft was then abrasive blasted to prepare the surface for the application of Belzona 1111. Two coats of Belzona 9411 release agent were applied to the shaft former and fixing bolts. Belzona 1111 was then applied to the worn shaft sections in layers to eliminate air pockets. The shaft former was then fitted to the shaft and fixed in position. All excess Belzona was removed while still pliable and the Belzona was left to cure for 12 hours.
Decontaminated and abrasive-blasted shaft, ready for Belzona 1111 application
Belzona 9411 release agent was applied to the shaft former and fixing bolts
Shaft former fitted to the shaft and fixed in position
Removal of the former revealed a perfectly formed shaft section measuring exactly to the OEM’s tolerances
After curing, the former was removed, revealing a perfectly formed shaft section. As previously mentioned, due to the Belzona product having no shrinkage, the measurements of the newly formed shaft were exactly within the manufacturer’s specified tolerances. The mould relief points were then lightly filed and polished to suit the existing shaft.
New bearings and seals were now ready to install. The bearings were heated and fitted using an induction heater, to ensure the bearings were fitted correctly the custom-made press tool was fixed in position while the bearings cooled. We installed the custom fixing ring to replace the shaft nut and tab washer. The fixing ring was heated, shrunk in position, and secured by four locking bolts.
Minor imperfections were filed and polished to suit the existing shaft
The bearings were heated using an induction heater to 110–120°C then fitted
A custom-made press tool was fitted to hold the bearing in position while it cooled
Fitting of the custom-made fixing ring with four locking bolts
The bearing housing and cover plates were then fitted and locked in position. Finally, we fitted the pulleys, belts and guarding to the vacuum pump and electric motor, and returned the unit to operation.
Bearing housing and cover plates fitted and locked in position
The repaired pump was returned to service within four days
OUTCOME
The repair was completed within four days with the pump promptly returned to service, ensuring minimal operational disruption. In addition, the in-situ solution was a fraction of the cost of conventional repair and prevented a prolonged outage and substantial financial losses to the customer.
More Information?
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Products
Belzona 1111 (Super Metal)
A 2-part repair composite for metal repair and resurfacing based on solvent-free epoxy resin reinforced with silicon steel alloy. This repair material will not corrode and resists a wide range of chemicals. It is easy to mix and apply without the need of specialist tools and can be machined using conventional tools.
About Rezitech
Established in 1968, Rezitech is the sole Australian Distributor for Belzona. Rezitech offers a comprehensive range of industrial protective coatings and epoxy metal repair composites to many different industries including: oil and gas, mining, power, water and waste water, pulp and paper, marine, manufacturing among others.
We value growth and innovation within the maintenance solutions industry
Our Mission
To provide industry with easier maintenance solutions that provide cost effective, efficient and long lasting results for our valued clients. To provide an integrated industry service by striving for Rezitech being a truly complete solutions provider!
Our Values
We value the needs of our clients and place a huge emphasis on providing specialist skills and knowledge.
From engineering to fitting, blasting or coating to sales, administration and customer service, we highly value our organisation and encourage diversity andgrowth to benefit our client and our team of people.
Our Vision
To strive for excellence in our delivery of high quality industrial maintenance solutions. To be our clients’ preferred choice when it comes to solving all of their maintenance and new pump needs while helping to reduce their carbon imprint.
Health and Safety
Rezitech is committed to ensuring the health, safety and welfare of its employees, contractors, visitors and customers who may be affected by Rezitech’s operations. We strive to pursue standards of safety that meet and exceed statutory duties.
Community & Environment
While providing solutions for our clients Rezitech focuses on identifying ways to improve business environmental performance while increasing productivity and reducing costs of production for the benefit our clients and hence the community.
The Future
To continue to strive for excellence! To continue to lead the way in industrial maintenance solutions and services and provide our clientele with high quality, complete and reliable products and services.
Rezitech’s mission is to make its liquid ring vacuum pump expertise available to sugar mills, paper mills and process industries worldwide. We currently export to:
- Fiji
- Thailand
- Mauritius
- Indonesia
- United Kingdom
- Phillipines
- Malaysia
- New Zealand
- Papua New Guinea
We are constantly on the look out for new export opportunities and new countries to export to Rezitech places an emphasis on the development of export business worldwide.
For further information on a Flowtech Distributorship please contact us.
