By: Mark Wood, Hayward Tyler, UK
Hayward Tyler has been manufacturing engineered metal products since 1815. The company has evolved in the best tradition of high quality British engineering. We are the world’s experts in producing large, high-pressure, glandless, boiler circulating pumps (i.e. sealless pumps) used in conventional and nuclear power generation businesses.
The basic concept was developed by Hayward Tyler more that 40 years ago, and there are now over 2500 units installed worldwide. These are in operation on both nuclear power stations and conventional fossil fuel fired power generating plants, including combined-cycle gas turbine, fluidized bed and IGCC (coal gasification) installations.
A boiler circulation pump, which was handmade in the UK, in action in China
When we supplied our first boiler circulation pumps in China back in 1979, it was not the expanding world-class economy we see today. Even before China had opened up to the outside world, our engineers were teaming up with the turnkey suppliers of the day, when they were called in by the Chinese electric power generating industry to build the first very large scale thermal power plants.
These plants were built at strategic inland locations such as Luohuang near Chongqing on the banks of the upper Yangtze river in Sichuan province (Stein Industries); Shentou in Shanxi province (Skoda Export) near the vast coal reserves around Datong; Beilungang on the coast near Ningbo (CE). Working with the Ministry of Electric Power, we proved the benefits of controlled circulation boiler technology and enjoyed a steady flow of orders for several years.
Pure and simple
The pressure integrity of the design is the main reason for the pump’s worldwide acceptance – a consequence of the simplicity of the pressure-containment design coupled to zero leakage. The pump consists of a fully submerged wet motor and rotodynamic pump arranged inside a pressure-tight enclosure with the minimum number of static seals.
As pump cases contain varying degrees of asymmetry and are subjected to various transient conditions during boiler start-up, shutdown and system load changes, computerized finite-element stress analysis techniques are employed. The pumps operate across a broad range of applications and duties, typically 294 ºC and 80 bar up to supercritical pressures and temperatures.
In the glandless design, the pump impeller is mounted directly on an extended motor shaft, and there is therefore no coupling or any pump/motor alignment issues. The motor is a fully submerged, wet stator, squirrel-cage induction motor housed in a pressure tight housing that is bolted to the pump case.
The windings, which are either star or delta connected, are continuously insulated with ‘cross-linked polyethylene’ (XLP), which is unaffected by water and isolates across a broad temperature range. The windings penetrate the motor case through specially designed terminal gland assemblies.
Tilting pad, (Michell type) self-aligning, water-lubricated bearings are utilized at all locations. Upper and lower journal bearings are used for thrust and, where applicable, reverse thrust duties. An impeller incorporated into the motor rotating element circulates water through the motor cavity to the top of the heat exchanger and back to the lower part of the motor. This recirculation provides cool lubricant to the bearings and dissipates the heat generated by the motor electrical losses (typically ten per cent). When the pump is on hot standby, natural thermal syphoning deals with the relatively small amount of heat that passes from the hot pump case through the thermal throttle to the motor cavity.
China’s economic boom
By the time the Chinese economy moved into top gear in the mid-1990s, the power plant managers who had installed our pumps knew they had chosen a product of high reliability. As direct commercial channels started opening up, Hayward Tyler was the sensible choice to satisfy the demands of the newly independent electric power engineering groups whenever boiler circulation (or in the case of supercritical boilers, boiler re-circulation) pumps were specified. Shanghai Electric, Harbin Electric and Dong Fang Electric of Sichuan each started to receive orders for as many as 50 large power plants per year. In particular, Shanghai Boiler Works, part of the Shanghai Electric Group, through their adoption of Alstom (CE) technology, favoured controlled circulation and became one of our biggest customers.
Our UK-based field sales, meanwhile, had been carefully cultivating relationships with the key personnel in all the big boiler companies. We spent more time with the boiler design engineers, who would then specify our equipment based on our engineering quality and reputation for reliability, rather than with the commercial negotiators, as our key to success is rarely due to price alone.
Through the period of closely regulated import of foreign technology, we watched competitors being drawn into joint venture partnerships with China-based manufacturers, but we kept our distance from this cost-saving alternative. Our pumps are individually designed and built to meet the specification of each individual customer. This style of manufacture, which relies on highly skilled bespoke engineering, has no great advantage in an economy where the savings come from labour costs. Only now that the private enterprise system is beginning to mature can owners and investors exercise more direct control over quality and source highly engineered components in China.
Tapping into the aftermarket
To date, we have supplied over 400 boiler circulation pumps to China, the majority running at 6 kV, with the remainder at 380 V, 3 kV and 10 kV. Traditionally, we had always drawn on experienced field engineers and field sales as back-up when needed. While the pumps can run for many years, even more than a decade without servicing, we still recommend removal, inspection and maintenance every five years. This, of course, led us into the China aftermarket, a very different story from the supply of high specification capital equipment.
The older power plants all had large maintenance teams, but usually they did not want to take the risk of working on our pumps themselves. Therefore we originally supported our products in the field (installation, commissioning, spare parts, technical support, etc) direct from our UK base.
This approach worked well until the thirst for economic and technical development in China extended into this area of high spec aftersales, and we began to see indigenous suppliers of spare parts and servicing eat away at our aftermarket business.
Our initial belief that local companies lacked the technology or credibility to provide these vital services was gradually shaken, and it became clear that to be successful we had to make a swift change in policy. As part of our ongoing development and investment in the Chinese market, a dedicated service centre was opened five years ago to service the growing installed population.
Here again, the company opted for full control to be able to maintain our reputation for reliability, to be able to say with confidence that the maintenance is carried out by Hayward Tyler engineers. Furthermore, for the sake of future sales of new equipment, it was vital we proved our full commitment to the China market. We now have a wholly owned foreign entity in Kunshan, just a one-hour drive from the centre of Shanghai. Our new service centre provides everything we need to out-class the local service providers and maintain the integrity of our products.
We stand out in the aftersales market because of our insistence on using only our own Hayward Tyler trained engineers and replacement parts manufactured either at our headquarters in Luton, UK, or by a small number of directly supervised local suppliers near our maintenance facility in Kunshan.
Our full-time, expatriate, China-based managing director apprenticed to Hayward Tyler when he was a young man and has over 30 years’ experience of working with our own equipment being supplied into the power generation industry.
Developing local skills
We chose Kunshan as a desirable location for skilled Chinese workers. Within 15 years, this city, one of the undisputed success stories of modern China, has grown from a small rural town, providing fresh produce for nearby Shanghai, to a modern industrial city. The environment and general living conditions are relatively good, with no old-style heavy industry in the immediate vicinity. There is a can-do attitude of good commercial sense, without the restrictions and complications of more traditional older large industrial communities.
At our maintenance facility, driven by the meticulous standards and enthusiasm of our managing director and the visiting UK-based field staff and technicians, fully flexible working practices are the norm.
Hayward Tyler’s Chinese maintenance facility in Kunshan
When a pump arrives at the workshop, as many people as needed are immediately available, hands-on, to lift the pump into the pit, remove the motor cover and start the dismantling process. We can get to the point of motor core removal within one hour of the pump arriving on site.
Whereas we have specialists in on-site installation and removal, in motor winding or machining, everyone is ready to learn new tasks to be available where needed the most. All the consumable spares are kept in stock on site, so assuming there are no unforeseen problems with the motor, we can turn around a full rewind of any motor within a few days.
When recruiting new skilled staff for our facility, we search the whole country. The specialist motor manufacturers, who would have winders, fitters and machine operators experienced in handling pumps and motors of weight up to ten tonnes, are spread all over China, and we have recruited from as far away as Xi An and Harbin.
We have found that in China, with its unimaginable number of skilled and semi-skilled workers, a university degree sets you apart as a person of culture and learning. For this reason, our winding teams, for example, are made up of two skilled winders and one engineer. As we develop and grow in China, we will always ensure a very high ratio of engineering graduates within the workforce. In addition, the engineers we employ will also have a reasonable grasp of English.
Looking into the future
Today, Hayward Tyler has a well established brand, a sizeable installed population and a wholly owned company serving a highly regulated industry in one of the largest markets in the world. We are confident that our sales of new boiler circulation pumps will continue at current levels for at least the next few years. Even if new plant construction in China levels off, it will start to export turnkey plant construction to other countries in the region, and the big boiler companies will need our pumps. This gives us a solid platform for future growth and diversification in both the supply of other new products from our range – such as subsea motors, chemical pumps – and in the high spec aftersales and servicing of all kinds of rotating equipment used in the power industry.