Resistance Heating Vacuum Sintering Furnace
It belongs to the technology of electric heating furnace. A resistance-heated ultra-high temperature vacuum sintering furnace is proposed in this paper.
Vacuum sintering furnace is a special technical equipment for ultra-high temperature sintering process of reaction bonded silicon carbide products, which can meet the requirements of industrial production of this product. In addition, it can also be used for sintering fine carbon-graphite products, graphitizing treatment, high temperature sintering of non-oxide ceramic products and other occasions. At present, in the domestic fine silicon carbide kiln furniture industry, all the large-scale ultra-high temperature vacuum sintering equipment with practical value are medium frequency induction heating vacuum furnaces imported from abroad. The price is very expensive, each set is 1300-15 million yuan, and the overall equipment design structure is relatively complex. At present, the resistance-heated ultra-high temperature vacuum sintering furnace produced in China can only meet the development of small samples in the laboratory stage, and does not meet the production requirements of large-scale practical products. High performance silicon carbide kiln furniture was developed and manufactured by resistance-heated ultra-high temperature vacuum sintering furnace. Its effect is no less than that of imported or domestic similar products manufactured by imported equipment. And make it have a lower cost, so as to reduce the production cost of high-performance silicon carbide kiln furniture, improve its market competitiveness, provide the necessary conditions. At the same time, it also provides the necessary equipment basis for the development of new SiC kiln furniture with independent intellectual property rights.
A resistance-heated ultra-high temperature vacuum sintering furnace is proposed to meet the industrial production requirements of high performance SiC kiln furniture.
Its main components include furnace body, resistance heating device, vacuum-pressure and ultra-high temperature detection part, etc. In resistance heating device, the two poles of power supply enter the sintering furnace through large current busbar and metal water-cooled electrode outside the furnace, and then connect to the heating body rack through transition electrode made of carbon-graphite material to form a complete loop system. In the resistance heating device, the heating body rack adopts a circuit structure with one end charging, one side heating body in series and two sides in parallel.
In the resistance heating device, the two poles of the power supply are introduced into the furnace through four metal water-cooled electrodes located on both sides of the furnace body. The two water-cooled electrodes and the transition electrodes on each side of the furnace body are connected to the upper and lower heating plates on its side, and the rear end of the upper and lower heating plates is connected to form a series circuit through a bridge plate. The parallel circuit is composed of symmetrically arranged heating bodies on both sides.
Another structural scheme of the resistance heating device is that the two poles of the power supply enter into the center of the upper and lower graphite transverse plates at the end of the furnace through two metal water-cooled electrodes parallel to each other at the end of the furnace body and are connected to the center of the upper and lower graphite transverse plates at the end of the furnace respectively, and the two ends of the upper and lower graphite transverse plates correspond to the upper and lower heating plates The tail end of the upper and lower heating plate is still connected by the bridge plate, forming a circuit form of one side in series and two sides in parallel.
Metal water-cooled electrodes can be set to four, divided into two sides, each side up and down.
The metal water-cooled electrodes can also be set to two, which are located at the end of the furnace body and are arranged up and down. The upper and lower graphite transverse plates at the end of the furnace are respectively connected by the transition electrodes, and then connected to the upper and lower heating plates on both sides.
The heating body adopts the design structure of one side heating plate in series and two sides in parallel. This circuit connection mode provides the possibility that the two poles of the power supply enter from one end of the sintering furnace. It makes the power bus shortest, saves the expensive investment of the bus and reduces the energy consumption of the bus. At the same time, it enables the key electrical connection parts to achieve close connection under reliable constraints, and completes them steadily. On the other hand, from a mechanical point of view, the single-side heating body plate is equivalent to a three-point restraint support system. Under high temperature deformation, the heating body plate can release the huge destructive stress which may be generated by the plate itself through a small displacement relative to the hanging shaft, thus ensuring the safety and stability of the plate system. In addition, the design of its current introduction structure. It can work reliably under the high current load of 8000-10000 amperes and the extremely harsh working conditions of withstanding the high temperature above 2000 C.
In a word, the structure characteristics of the heating plate frame of the sintering furnace are:
(1) the two poles of the power supply enter from the end or both sides of one end of the sintering furnace;
(2) the upper and lower heating plates on one side are connected in series and parallel on both sides;
(3) the supporting system of the heating plate frame on one side ensures the close connection of the electrical nodes on the one hand, and on the other hand, the safety and stability of the plate system under high temperature conditions.
(4) The heating body frame structure of the invention lays a reliable technical foundation for the large-scale engineering implementation of the sintering furnace.