Component reconditioning is very popular
Component reconditioning has many advantages. This is especially true in case of large, heavy components:
- Reconditioning usually represents a cost saving of 50 – 70% compared to replacement
- Reconditioning a component nearly always takes up significantly less time than fabricating a new one
- Long lead times or supply chain crunches are less of an issue, as supply chains are shorter and simpler
- No new part might be available when one is needed. To reduce risk and stock keeping costs, OEMs manufacture and sell spare parts for ever shorter time periods only.
- Reconditioning results in a smaller carbon footprint than replacement
Given these advantages, it is hardly surprising that component reconditioning has been widely used for many years in industries such as marine and power generation, where components are large and where equipment life is long.
But, what does reconditioning actually mean?
Dictionaries and thesauri usually equate the word “reconditioning” with “to put into working order again” or “to put back in shape”. Proposed synonyms are: To fix, mend, patch, renovate, repair and revamp.
This implies that the goal of the reconditioning process is to put the component back into the state it was before it got worn or damaged.
At QuantiServ, we are convinced that we should do much more than to put a component back into its original, unworn condition. We set the bar much higher for ourselves. After all, we are one of the largest reconditioning companies in our industry and we have in-house research and development resources, that enable us to continuously push the technology envelope. Noblesse oblige, as the French proverb goes.
We believe that whenever a machinery component undergoes reconditioning at one of our four reconditioning centres, we are presented with an opportunity to not just put the part back to its original condition, but to improve on it. We habitually apply new technologies, modern materials and advanced processes to improve component design, leading to a better performance and extended Time Between Overhaul (TBO).
This sets us apart from all the low-cost reconditioning companies. These companies return to their customers components that – in the best of cases – perform as good as when they were new, but never better. Unfortunately, by so doing, these companies forego customer value by providing sub-optimal service.
There are many good examples of how we have lived up to our high standards and have engineered, manufactured and delivered to our customers improved components that have subsequently shown superior performance. An illustrative example comes from a power plant in the Caribbean, that suffered from very short TBOs. Pistons on these 90-bore engines had to be pulled every 3’000 running hours, to replace piston rings, pistons and, sometimes, even cylinder liners. To solve the problem of such unacceptably short maintenance intervals and component life-times, we have thoroughly analyzed and then redesigned some components of this 90-bore, two-stroke engines. Specifically, we have altered the number of piston rings, have coated the piston ring grooves with our QS50K material and have applied a coating to the piston skirts.
The result of these modification is that the TBO could be increased from 3’000 hours to 18’000 hours!
Three piston rings instead of five
In internal combustion engines, piston rings seal the combustion chamber. While the piston rings’ purpose is unambiguous, it is less clear how many piston rings are required, to get the job done effectively. Historically, four or five piston rings per cylinder were deemed necessary on low-speed, two-stroke diesel engines. Simulations and field experience collected by us in recent years has shown that on many engine types, pistons with only three or four piston rings perform better than those with five. “Less is more”, when it comes to piston ring tribology.
Anti-friction coated piston skirts
A well performing forced piston cooling system is essential, especially on engines that operate on heavy fuel oil (HFO) to maintain a relatively low and stable core temperature. If the piston temperature rises above a critical threshold, then galling, scuffing or seizing will occur due to thermal expansion and breakdown of the oil film between the piston and cylinder liner.
The performance racing industry has been using coated pistons for some time already for this very reason. These so-called anti-friction coatings, that are applied to the piston skirts, are essentially dry film lubricants with a very low friction coefficient. This results in low friction forces and a reduction of parasitic drag, while also decreasing heat saturation in the piston skirt and core.
Anti-friction coatings offer the following benefits:
- They act as a thermal barrier coating and reduce metal-to-metal contact
- They increase component life time and TBO due to a lower wear rate
- Reduced friction (a parasitic loss) results in a lower fuel consumption
- They support oil film formation and therefore reduce the risk of galling, scuffing and seizing, particularly under challenging operating conditions such a running-in, high load operation and load changes
An excellent example of us improving engine component design is the development of our QS50K pistons. From a few years ago, many customers reported excessive wear in the piston ring grooves. The customers informed us that pistons with chromium plated ring grooves, which has been the industry standard for decades, would only last for a few thousand running hours. As reported this applied, in equal measure, to new as well as to reconditioned pistons and to many different engine types.
Our engineering and development colleagues started to investigate. They eventually developed an entirely new process of coating the piston ring grooves. They replaced the chromium in the ring grooves with a very advanced, proprietary material formula which has been proven to easily last for 20’000 hours and more. The successful development and market introduction of the patented QS50K coating process is a good example of how QuantiServ developed a solution to problems reported to us by our customers.
Since its introduction, more than one thousand QS50K pistons have entered service. The earliest ones have meanwhile accumulated well beyond 30’000 running hours!
In the case of the Caribbean Power Plant we have also supplied special piston rings that the engine OEM does not have in his portfolio for this engine type. This, in addition to implementing the modifications described above.
QuantiServ’s enduring commitment towards resource reduction and sustainability is demonstrated by our membership in the Association for Sustainable Manufacturing (MERA). We proudly carry MERA’s Manufactured Again Certification Mark, which is a recognizable symbol
that represents the quality, value and sustainability of our processes.
Example of anti-friction coating on 90-bore piston skirts in our reconditioning centre in Kruiningen, in the Netherlands. Once the anti-friction coating is applied, the piston skirts get cured in an oven. As is usually the case, reconditioning of these piston skirts included the replacement of the four bronze bandages.