Patrik Gustafsson, Sales Director, Högfors Group
Reijo Rintala, Managing Director, HögforsSahala
The Högfors Group consists of four companies specialising in energy and flow technologies. The core competence of HögforsSahala covers heat exchangers and other demanding pressure vessels. HögforsValves focuses on valves and flow control. HögforsSteka manufactures power boilers and boiler components. HögforsGST specialises in district heating substations for real estate units, district cooling and industrial heat distribution.
Högfors has its roots in the 19th century. The first valves were made as early as 1935, and heat exchanger production was started in the 1950s. Today, Högfors solutions are used to secure the reliable supply of energy for the needs of various industries, homes and other users throughout the world.
Heat transfer and pressure vessels
The transfer of thermal energy constitutes the central element in the operation of any power plant. All heat transfer applications are essentially required to function continuously, effectively, reliably and independently of the varying external conditions.
HögforsSahala specialises in heat transfer technology – its heat exchangers cover all the needs and requirements imposed by the energy industry’s processes.
The company’s product palette covers heat exchangers for nuclear, fossil fuel and biogas power plants, in addition to other pressure vessels, including:
» high-pressure feed water preheaters
» low-pressure feed water preheaters
» heat exchangers for district heating
» condensers
» auxiliary condensers
» feed water tanks
» steam accumulators.
The company’s development work extending over many decades, combined with its experience of hundreds of deliveries have refined the efficiency of HögforsSahala’s thermodynamic heat exchanger solutions. These solutions enable optimal heat balance management for the various power plant types – in all production situations.
Pic 1: HögforsSahala’s solutions cover all heat exchangers and the feed water tank of a power plant.
High-pressure feed water preheaters
Högfors high-pressure feed water preheaters are of the U-pipe type and applicable for vertical and horizontal installations. The water chambers of vertical preheaters may be mounted in the heater’s upper or lower end. Preheaters are frequently provided with internal steam desuperheating and drain cooling sections.
Pic 2: High-pressure feed water preheaters at a CHP plant in Jyväskylä, Finland
Low-pressure feed water preheaters
Most of our low-pressure feed water preheaters are also of the U-pipe type and applicable for vertical and horizontal installations. In their design, special attention has been paid to degasification and pressure drop in the drain cooler.
Heat exchangers for district heating
The reliability of heat exchangers and their thermodynamic properties are decisive elements in the efficiency of district heating power plants. In the design of heat exchangers for district heating, we have paid special attention to the supply of incoming steam and the efficiency of degasification. In terms of reliability, the most important targets include the elimination of erosion effects, vibration management and minimising the oxygen content of the condensate. The temperature approach and related structures of the district heating heat exchangers are dimensioned in accordance with the customer’s requirements.
Pic 3: District heating valves in Russia.
Condensers
Our condenser design focuses on functional reliability, with special attention being paid to vibration control and the elimination of erosion effects. Efficient degasification is also an important property that enhances the condenser’s capacity in demanding conditions. Condensers often use divided water chambers that are provided with flow deflectors in accordance with the purification system’s requirements if necessary.
Auxiliary condensers
An auxiliary condenser is an important process backup device which must start up quickly and reliably as required. This means that the auxiliary condenser must be able to withstand rapid changes in flow volumes and wide temperature variations.
Pic 4: Type 31300 is a metal seated butterfly valve with a stainless disc and stem
Feed water tanks
HögforsSahala’s structural solutions for feed water tanks are the result of long-term product development work. Degasification systems operating on the cascade and spray principles, as well as the entire feed water tank are all individually designed and dimensioned to match each plant’s specific requirements.
Steam accumulators
A steam accumulator is a central element in steam systems used by the process industry. It can be used to balance steam production and to compensate for process load variations and unexpected malfunction situations by increasing the steam volume contained in the network, or by storing the surplus steam produced. The steam accumulator can also function as a short-term power reserve, in situations where steam production is interrupted.
HögforsSahala’s steam accumulators are designed and dimensioned in accordance with the steam network’s process technical requirements and plant-specific production strategies. This ensures that the resulting accumulator construction is reliable, suited to its purpose, cost-effective, and functions reliably even after decades of pressure variations.
Pic 5: Butterfly valve 31100 is used for demanding open/close and regulating tasks.
Methods and materials
In addition to efficiency, energy production requires extreme reliability and durability. This means that all the materials used in the manufacture of power plant equipment must be selected individually, in accordance with each installation’s special requirements. Nevertheless, mere material selection is not enough – you must also profoundly master the manufacturing processes, and the welding methods in particular, in compliance with the process-specific special conditions.
Due to the great variety of power plant equipment requirements, we use an extensive selection of raw materials, covering all the requirements imposed by power plant processes. A few examples of the typical metals we process include:
» carbon steels
» stainless steels
» heat-resistant steels
» titanium
» copper alloys.
Special process requirements and material properties are also observed in our design and manufacture. This takes place using state-of-the-art technology, including vibration analysis for the mathematical modelling of equipment vibrations, and the Finite Element Method (FEM) for material strength calculation purposes. We also use a complete set of approved welding methods covering a great variety of materials and process requirements.
Flow control is a central element in energy production
Energy production and transfer require total control over a wide variety of flows. Processes contain flows of steam, condensates, water, fuels, lubricants and compressed air – all requiring reliable and accurate control.
HögforsValves develops and manufactures shut-off valves, control valves and strainers, offering an extensive valve palette for the needs of district heating networks and power plant low-pressure lines.
Extreme precision enabled by modern valve production technology
Högfors has produced valves for the past 70 years. In addition to its products, the company’s manufacturing technology has been refined by long-term development work. The experience and expertise gained over many years is summarised by HögforsValves’ new production plant that started up in 2009.
The Flexible Manufacturing System (FMS) machining line is almost 60 metres long and provided with 5-axle machine tools that are applicable for 3-D surface processing. This guarantees flexible production and unique machining precision.
The production line works by the one-piece flow principle, which means that each valve being manufactured may be of a unique type. This makes it possible to take each customer’s individual needs into account, in addition to short delivery times.
The machining precision extends to the level of one micrometer, enabling complete valve tightness at increasingly higher operating pressure levels. For example, 25 bar butterfly valves provided with metal seals, can be manufactured in accordance with the A tightness class requirements, in both flow directions. In addition, all Högfors valves are checked and pressure-tested before leaving the factory.
Butterfly valves designed for the needs of energy production
Högfors manufactures valves of size category DN15-1400. The main product is a butterfly valve provided with a metal seal, specifically designed for power generation and distribution pipelines.
Thanks to their construction, Högfors butterfly valves are tight and extremely durable. This ensures their reliable operation in the long term, even in extremely demanding conditions.
Högfors butterfly valves are manufactured to comply with the maximum pressure category PN25, with the highest permissible temperature level for standard valves being 260 °C. Valves that withstand higher temperature levels may be manufactured as per order.
Since Högfors valves have been supplied throughout the world over the years, they currently fulfil the local requirements of numerous countries in addition to the ISO standard requirements.
