Beyond the large units driving generators, small steam turbines are commonly used in parallel with electric motors to power important assets such as pumps. Keeping these smaller turbines properly maintained is essential for continued performance and reliability. Sulzer has a network of specialized facilities that are equipped to service these turbines as well as the rotating equipment that they drive.
Small steam turbines, typically producing less than 1,500 hp (1,100 kW), are often used in industrial environments, such as chemical, oil refinery, paper mills, power plants, and many food industries. These may be a primary driver or a standby unit for the back-up of a motor-driven unit.
Typical service intervals for small steams turbines are six to seven years, with biennial planned maintenance. Steam conditions play a major role in increasing unit availability and downtime for repairs. Where wet steam conditions are found, various coatings can be applied to reduce wear. A field site visit to review case, steam valve, and carbon gland leak-off provisions is key to ensuring the drain or leak-off is adequate to minimize the wear on turbine parts.
It is important to understand the key points of a small steam turbine that need to be properly maintained for continued safe and efficient operation. At the top of this list is the overspeed trip mechanism. The trip safety device is designed to operate in the event of a governor failure and prevent the turbine from increasing in speed to the point of destruction. It is essential that any turbine overhaul includes a check for the correct operation of the overspeed mechanism.
Steam turbine health relies on the bearings being properly maintained. These could be a roller bearing or a white metal, Babbitt, bearing, both of which need to be monitored for wear and to highlight any signs of failure. These may include water contamination of the oil system, misalignment, or incorrect oil levels. Frequent monitoring of oil quality, oil temperatures, and performing scheduled vibration measurements for analysis is key for turbine reliability.
Sulzer has a long-established expertise in steam turbine design, operation, and repair. Decades of experience of working with assets from a wide variety of manufacturers means that customers can benefit from a rich bank of knowledge and understanding.
Coupled with a network of service centers that are equipped with all the necessary machine tools, and the ability to maintain all types of rotating equipment, Sulzer offers a local one-stop-shop for a wide variety of machinery repairs. This includes small steam turbines, which can be fully tested using in-house test stands and lube oil systems that have been installed specifically for this service.
In the USA, Sulzer has five specialist small steam turbine repair centers strategically located throughout the country. Field service teams can provide onsite services as well as remove, install and commission assets for minimal downtime, while the workshops offer a comprehensive range of services including reverse engineering of failed parts.
Sulzer operates an open door policy where customers are invited to visit the service center and witness repair and testing procedures. These include disposition to review recommended repairs or upgrades, balancing of rotors, running clearances, and the all-important overspeed test.
Sulzer’s expertise in pumps and other rotating equipment means that operators can take advantage of extensive knowledge of pumps and their drivers and benefit from the company’s expertise and knowledge in many pieces of equipment. This offers a more encompassing service where complete drivetrains can be inspected and repaired by the same maintenance provider.