High temperature industrial fans (heat-proof fans) designed by OJSC "VNIIMT" Development, design and manufacture of heat transfer convection thermal furnaces on the basis of the high temperature industrial fans (heat-proof fans) designed by OJSC "VNIIMT" Fig. 1 Heat proof furnace fans designed by VNIIMT Goal Intensification of heating and cooling processes in convective furnaces due to high speed gas atmosphere blowing along the processed materials in workspace, in order to improve furnace productivity and product quality. Problem Increasing convection furnaces productivity and quality of products obtained, is currently largely limited by technical capabilities of existing industrial heat-proof fans. The main problems hindering the efficient operation of such devices are: the lack of performance and drop pressure, generated by heat-proof fan; the lack of reliability and short lifetime heat-proof fans; inability to use centrifugal fans as reversing devices in furnaces with a periodic change in the direction of gas atmosphere moving without regulatory and closing valves. Solution The use of industrial heat-proof fans designed by OJSC "VNIIMT" when engineering new convective heat transfer type furnaces and systems and upgrading existing ones. Results The use of industrial heat-proof fans designed by OJSC "VNIIMT" in convective furnaces results in: significant increase in quality of products due to a steady flow of heat transfer agent during the heat treatment process; increase in convective type furnaces performance by 15-20% due to intensification of heating or cooling processes; increase in fans lifetime by 30-50% due to the latest design of impellers and bearing assemblies used in heat-proof fans; reduce in power consumption by 5-8% due to high efficiency of the fan; lowering temperature gradient non-uniformity of long workpieces (e.g., pipes) through the organization of a patented OJSC "VNIIMT" reverse gas flow system without using valves - reversible centrifugal fans.
Fig. 2 Heat proof (high temperature) impellers designed by VNIIMT for furnace fans. Parameters of high temperature industrial fans (heat-proof fans) designed by OJSC "VNIIMT" used in convective type furnaces Performance up to 80000 m3 per hour Total Pressure up to 5000 Pa at 20 C Maximum temperature of the pumped gas atmosphere 700 C Maximum temperature of the pumped gas atmosphere in heat-treatment 950 C furnaces with protective blanket (endothermic gas, hydrogen etc.) Impeller diameter up to 1250mm RPM number of the impeller depending upon the diameter 400-1450 Motor power depending on performance, temperature and pressure of 1-120kW the fan Shaft and bearing parts cooling system - built-in air system
Fig. 3 Customized bearing assemblies of heat proof furnace fans for aluminum products homogenizing Fig. 4 Heat proof furnace fan frame with a customized bearing assembly for vertical hardening furnaces High-temperature (heat proof) industrial fans and exhausters OJSC "VNIIMT" develops, manufactures and supplies high-temperature industrial fans and heat proof exhausters in gastight design to move various gaseous environments (air, endothermic gas, carbon dioxide) with the temperature up to 800 C. This force-draft equipment can also be used as remote circulatory fans for heat transfer type furnaces. Fig. 5 High temperature circulation fan
High temperature fan (exhauster) consists of the following parts: a frame, a stand, a chassis with a heat resistant impeller, a built-in shaft cooling air system, a spiral case (volute) with thermal insulation, an electric motor, a belt joint (V-belt drive). After the inlet and outlet pipelines are connected the heat proof fan (exhauster) is ready for operation. The fan (exhauster) parameters are adjusted by changing the rotating speed of the heat proof impeller using the electric drive frequency control. OJSC "VNIIMT" also has the ability to manufacture high-temperature (heat proof) impellers according to customer's drawings or to develop new designs of impellers with required parameters. Fig. 6 High temperature industrial fan Fig. 7 Heat insulated spiral case (volute) Nonstandard chemically resistant fans and exhausters designed by OJSC VNIIMT Design and supply of nonstandard chemically resistant fans and exhausters (fans for chemical industry) with required technical parameters. For example, high pressure of pumped medium with low capacity, high temperature, aggressive environments (if necessary fan impellers can be made with a special chemically resistant coating chemically resistant impellers), protective furnace atmosphere, special requirements for the size, replacement of imported fans and exhausters for fan equipment with the same aerodynamic characteristics and connection dimensions, etc. Design and supply of fan bearing assemblies are possible at the request of the customer.
Fig. 8 Nonstandard chemically resistant exhauster designed by VNIIMT Fig. 9 Nonstandard high pressure fan designed by VNIIMT Fig. 10 Customized input of high pressure fan designed by VNIIMT
High pressure small-sized fans Fig. 11, 12 Separate small-sized high pressure fans designed by VNIIMT for burners OJSC VNIIMT carries out the following types of works: Design and supply of jet-circulation devices (jet cooling units) for cooling stripes and rolled metal (pipe) in catenary and pusher-type furnaces with protective atmosphere. Design and supply of water-cooled section (water cassions), equipped with built-in heat transfer intensification system for catenary and pusher-type furnaces with protective atmosphere. Design and supply of gas-dynamic obturators (inlet and outlet valves) for catenary furnaces where metal stripes are thermally treated in protective atmosphere. When the equipment is designed, our experts make gas dynamics, aerodynamic, strength and thermal calculations based on the finite element method with the help of modern computing devices. The calculation results are shown in figures. Fig. 13 Calculation results of temperature distribution along the length of furnace (heat proof) fan shaft (cooling system of the shaft is not shown conventionally)
Fig. 14 Calculation results of flows in the impeller and spiral case (volute) of a customized fan Fig. 15 Calculation results of stress distribution in the impeller of the furnace fan Fig. 17 Calculation results of thermal flows and temperature distribution inside the heating chamber of the furnace for metal heat treatment in protective atmosphere
Examples of use Heat transfer and thermal furnaces equipped with high temperature (heat proof) industrial fans designed by OJSC VNIIMT are used by the following companies: OJSC «VSMPO-AVISMA Corporation», Verkhnaya Salda; OJSC «Kamensk-Uralsky Metallurgic Plant», Kamensk-Uralsky; OJSC «Sinarsky Pipe Plant», Kamensk-Uralsky; «Zinc Coatings» Ltd., Magnitogorsk; CJSC «Welding Materials Plant», Berezovsky; CJSC «Polistil», Lysva, Perm krai, etc. OJSC VNIIMT has supplied more than 350 high temperature (heat proof) industrial fans for different types of furnaces to ferrous and non-ferrous metal plants. Turnkey Services Feasibility study on construction or modernization of convective heat transfer type furnace; Technical specifications, project work and design documentation; Furnace equipment and heat-proof fans manufacture; Equipment furnishing and installation; Launching works, commissioning, operational documents preparation. In addition, OJSC "VNIIMT" conducts regular maintenance of the equipment supplied, including diagnosis of the furnace unit, static, dynamic balancing and vibration control for heatproof fans, which ensures high technical and economic performance of customer s furnaces during the entire period of operation. Contact Us Research institute of metallurgical heat engineering OJSC "VNIIMT" Studencheskaya St. 16, Yekaterinburg, 620137, Russia. Head of Laboratory Vladimir Kalganov Tel/Fax +7 343 383-75-69 Email: aup@vniimt.ru, lab46@vniimt.ru