The structure of the series carburizing furnace by furnace shell, lining, lid lifting mechanism, sealed furnace fan, muffle tank, heating elements and electronic control systems and other components. Furnace shell made of welded steel plate and steel. Lining is 0.6g / cm3 energy-saving high-strength ultra-lightweight refractory bricks, ceramic fiber, asbestos board diatomite insulation bricks and masonry from energy-saving composite structures. Lid lifting mechanism consists of motor, gear pumps and other components, when the lid is opened, simply press the button on the control box, the lid that is to speed 30-70 mm / sec to rise. For safety reasons, the lift shaft fitted with two limit switches, when the lid rises, the lower limit switch automatically cut off carburizing furnace control cabinet main circuit power supply, the heating element power to stop working, the upper limit switch axis movements are restricted raising the height of the tube furnace to prevent rising too high lift pumping prolapse. Application of PLC in vacuum heat treatment furnace control system have? Vacuum heat treatment furnace is used in the manufacturing industry, in order to make industrial products with good properties necessary intermediate step, which is a branch of the heat treatment, the main purpose is to prevent oxidation and decarbonization workpiece during processing. Due to the application of programmable controllers microelectronics and computer technology, a variety of control functions are implemented by software, as long as changes in the program, you can adapt to changes in the production process, and therefore adaptable. It is not only able to complete the logic operation, timing, counting, and other functions of laboratory furnace, and can perform arithmetic operations. Thus can perform switching control, but also for analog control, but also with the computer into a network and achieve hierarchical control. Moreover, PLC, small size, light weight Dingtan burning furnace tube, compact, short development cycle, installation and less maintenance. Therefore, in the process of industrial furnace with microelectronics technology to transform traditional industries, the traditional relay control system, most of them were replaced by PLC. _ Longkou laboratory furnace laboratory furnace (certified) _ furnace experiments by Longkou Furnace. Longkou experiment Furnace (www.lk-dianlu.com) is a leader in Yantai, Shandong Province, electric equipment, over the years, the company is implementing the scientific management, innovation and development, the principle of honesty and trustworthiness, and satisfy customer needs. Longkou laboratory furnace leadership with the staff warmly welcome all inquiries negotiations to create experimental furnace Longkou a better future.