Polish Furnace Transformation

Mannings Thermal & Environmental Engineers Limited of Southport have announced the completion of a remarkable project in Poland to modernise an old brick lined bogie hearth furnace and convert it from electricity to gas.

The furnace, which is over 25 years old, was originally manufactured in Russia but had never actually been used. The work was carried out for Enargomontaz - Polnoc who wanted to stress relieve large steel pipe bends of up to 1.5 metre in diameter and 40 mm thick. They were looking for energy efficiency and a rapid cycle time as well as high quality end products. Mannings visited the factory in Sochaczen, which is to the west of Warsaw, to survey the furnace and to establish how the transformation could be achieved. After taking measurements and doing some calculations they were able to put forward an acceptable proposal which involved extensive alterations to the unit. While the customer set about demolishing the unwanted parts of the furnace and preparing the gas supply, Mannings completed their customised design and began manufacturing the new components. A kit of parts was then sent to the site in three containers to allow the reconstruction to commence.

The furnace hearth was completely replaced using hardwearing firebrick and the internal walls were lined with modern low thermal mass ceramic fibre insulation. It was necessary to fit a new door and chimney and to install an efficient sealing system to minimise energy loss from the heating chamber. The new heat source comes from medium velocity nozzle mix gas burners, which were positioned on opposite sides of the furnace. The burner ancillary equipment including flow controls, pressure regulators, shut off valves as well as an air/gas ratio balancing system were supplied as pre-assembled units, which had been tested to the latest safety standards before despatch. George Wright, who is Project Manager at Mannings said, " the smooth running of the project was the result of careful planning and every detail was checked and double checked before we sent the equipment to site".

A feature of the new installation is the forced cooling system. This comes into operation automatically at the cooling stage of the stress relieving cycle. At a predetermined point in the cycle the chimney is by-passed and cooling fans blow air over the hot products through ports in each side of the furnace and this air is exhausted by special pneumatically operated roof vents.

The furnace control panel includes a microprocessor programmer as well as a multi-point chart recorder. Temperature measuring thermocouples monitor the operating temperatures inside the furnace and up to 12 thermocouples can be connected to the parts being heat-treated. These thermocouples are plugged into sockets at the side of the unit so that they can be linked up to the panel. The furnace control system also includes many safety features and operation is fully automatic. Up to 15 tonnes of pipe can be heat treated to a temperature of 1150 degrees centigrade in a single load and the temperature uniformity is maintained to within plus or minus five degrees.

Four engineers travelled to Poland to carry out the modifications, which took six weeks to complete. Commissioning trials were also conducted to ensure that the system met the requirements of the customer. Further orders, for similar work is expected from other clients who wish to improve quality and reduce running costs by replacing outdated equipment.