well furnace main structure

pit type furnace is a periodic operation furnace, which is suitable for the heat treatment of rod and long shaft parts. The structure of the pit furnace is: the furnace body is a cylindrical deep well, and the workpiece is vertically loaded into the furnace by a special crane for heating. The fuel used is usually gas and fuel oil. When electricity is used as heat source, it is called well resistance furnace.

pit type furnaces are generally installed below the ground level of the workshop, but also above the ground level, or half above and half below the ground level. The names of pit furnace include: forced convection pit furnace, natural convection pit furnace, well gas carburizing furnace, etc. The well type furnace is one of the main boiler forms in the mechanical processing and production. The well type furnace has a good processing effect in the spherical treatment of carbon compounds in steel.

The reason is that the protective atmosphere often appears in the production of this equipment, which can ensure the surface accuracy of the workpiece after completion, and effectively ensure the toughness and rigidity of the workpiece. Based on these advantages, pit furnace is widely used in social production, and its demand is increasing year by year.

The well type furnace can use gas or liquid fuel or electric heating. When using gas fuel, there are usually several burners with small energy, which are installed along the tangent direction of the inner wall of the furnace. They are arranged in layers or spirals at a height to avoid the flame washing the workpiece directly and ensure the temperature in the furnace is uniform. When it is used for low temperature tempering or oil as fuel, a thin muffle wall is built in the furnace to separate the combustion space from the heating space, but the well type furnace with muffle wall consumes a large amount of fuel.

The well type furnace is mainly composed of outer cover, inner tube, convection tube, combustor, bottom stirring circulation fan, strong cooling fan, methanol cracking furnace, etc. The outer cover is composed of steel plate shell, furnace lining and furnace top lifting beam. The outer cover is the structural support of the whole furnace body. A pair of guide rings are arranged at the lower part to cover the guide pillars with slightly different height on both sides of the hearth, so as to ensure that the center line of the shroud and the hearth coincides. The function of the inner cylinder is to separate the gas flow space from the controllable atmosphere flow space of the workpiece, and at the same time, it is the heat exchange surface in the heat transfer process. The inner cylinder has good sealing performance, high temperature resistance and oxidation resistance, and has certain rigidity, which can increase the heat exchange area, reduce the deformation and prolong the service life.

The function of the convection tube is to ensure that the materials to be treated are separated from the inner tube, and to provide a convection channel for controllable atmosphere. The hot gas flow first rises along the annular gap between the convection tube and the inner tube, then turns downward and enters the material stack. The flow rate of gas in the annulus is high and constant, which is beneficial to the heat transfer between the gas flow and the inner cylinder.

A stirring fan is installed in the center of the furnace bottom. During heating, the circularly flowing controllable atmosphere passes through the annular gap between the convection tube and the inner tube, and the heat is obtained from the inner tube and transmitted to the workpiece. The fan operates in the whole cooling stage, producing strong convection in the loading space. The controllable atmosphere takes away heat from the workpiece and transmits it to the inner cover. The mixing fan adopts frequency conversion speed regulating motor, the speed of motor can be adjusted according to the temperature in the furnace, which has the characteristics of accurate speed, convenient use and maintenance.