In recent decades, the demand for higher-quality, refined steels has increased steadily. At the same time, steel plants operate under the increasing pressure to design their processes more energy-efficient and reduce CO2 emissions drastically.
Higher-grade steels which are demanded e.g. by the automotive or aerospace industry require further treatment in the so-called secondary metallurgical processes, which are often carried out under vacuum. Degassing, especially those with oxygen insufflation, as in VOD and RH-OB methods, produce potentially explosive gases. Vacuum components and equipment with ATEX approval enable safe and cost-efficient solutions for mechanical vacuum solutions.
“Today’s international standards for mechanical vacuum systems are based on the latest generation Roots-type vacuum pumps and dry screw-type vacuum pumps. Selecting such modern mechanical pump solutions also offers outstanding process control possibilities, and employs a very reliable design, enabling the pumps to survive inside the harsh steel plant environment. By installing standard pumps in multiple arrangements, even highest suction requirements can be fulfilled with competitive pricing, while focusing on high safety standards” explains Uwe Zoellig, Senior Manager Market Segment Process Industry.
ATEX vacuum solutions from Oerlikon Leybold Vacuum consist of pumps and components that meet the specification of ATEX Cat 2 (i) G IIC T2. This equipment can be combined into ATEX certified vacuum systems. To meet the requirements, an additional gas cooling and temperature control between the pumps is provided to prevent gas temperatures from exceeding the defined limits.
Furthermore, all pumps are controlled and monitored by a specially programmed frequency converter.
Regarding the vacuum pump set, potential ignition sources such as overheating or electrostatic charging must be considered, which will be achieved with the usual attention during design and manufacturing of ATEX-certified pumps. In particular, the pumps must be protected efficiently against overload by too high pressure differences in order to avoid excessive temperatures.
This is valid for all possible operating point starting with high suction pressures, passing to medium operating pressures, that are to be hold over a longer time as for example during delayed pump down in the VD-process or during the oxygen blow phase in the VOD-process, down to lowest end pressures with its high compression ratios.
Capable products alone do not guarantee trouble-free operation of the degasser. User errors can be made with an insufficient system design. The vacuum pump supplier must be able to combine the single products into a smart turnkey solution to ensure a satisfied user. The modern and highly performant vacuum solutions of Oerlikon Leybold Vacuum consist of two different standard pump models only, combined into three-stage vacuum systems. Such three stage designs allow highest suction speed combined with lowest power consumption.