The flue butterfly valve's outline and structural characteristics

In the nickel smelting system and the associated flue gas chemical product network, the flue butterfly valve is mainly used to regulate the treatment of flue gas from pyrometallurgical processes (such as flash furnace, converter, copper synthesis furnace, oxygen-enriched top-blown smelting furnace or The flue gas produced by the depletion furnace). Concentrate drying is one of the main processes for material preparation in the smelting system. The process flow is to mix 8% to 10% of wet concentrates containing ore with hot gas produced by the combustion of pulverized coal and pass the “three-stage” air drying. To dry ≤ 013% of the concentrate. The flue gas acid plant mainly includes purification, conversion, dry absorption and acid reservoirs. The temperature of the flue gas used for the smelting and the flue gas used for acid production is relatively high and the catalyst dust is large, which has corrosion and retardation effects on the pipeline valves. Flue and butterfly valve for smelting and acid-making pipe network shall be structurally designed according to the conditions of its working conditions, so as to avoid the normal opening and closing of the flue and butterfly valve due to thermal deformation and dust adhesion of the valve wall and ash plugging of the valve, affecting the smelting chemical equipment normal operation.

Structural characteristics of flue butterfly valve

According to the analysis of the standard regulations and actual use conditions, when the flue gas butterfly valve is used to cut or regulate the medium, the sealing performance requirements of the flue gas butterfly valve are different from those of the metal sealing butterfly valve. As a control device for dust and flue gas in the pipe network, leaving a certain gap in the closed position will not affect the automatic control of the pipe opening adjustment to the furnace pressure. The flue gas butterfly valve and the metal sealing butterfly valve have similar fluid characteristics, and the relationship between the opening degree of the butterfly valve and the flow rate is basically a linear proportional relationship. If used to control the flow, its flow characteristics are closely related to the flow resistance coefficient of the supporting pipeline. If the caliber and the form of the two pipeline installation valves are exactly the same, and the pipeline loss coefficient is different, the flow difference of the valves will be very different. If the valve is in a state of large throttle and the butterfly plate is in the middle opening degree, during the closing process, the two sides of the butterfly plate can form completely different states. The front end of the butterfly plate moves along the medium flow direction, and the other side The reverse flow of the medium moves. Therefore, one side of the valve body and the butterfly plate form a nozzle-like opening, and the other side is similar to the orifice-shaped opening, the nozzle side faster than the throttle side of the flow rate, and the throttle side often produces negative pressure, so the smoke When the butterfly valve is installed horizontally, the nozzle should be placed on the lower part of the pipeline to avoid the phenomenon of ash blocking at the connection of pipeline valves.

The flue gas butterfly valve mainly acts as a shutoff and regulates the flow. Especially for the large-diameter butterfly valve, working conditions affect the valve deformation factors and the deformation amount is not easy to control, so the structural design should consider the influence of environmental factors. The flue gas butterfly valve radial seal and the metal seal butterfly valve are similar in structure, and the heat resistance is easily generated in the application process due to the influence of temperature, which affects the opening and closing of the valve.

Flue butterfly valve seal form is ideal for plane sealing. It can be designed as a vertical plate or inclined plate structure (as shown in the figure above). The valve body and disc plate are sealed by the side plane. The outer diameter of the butterfly plate can be smaller than the diameter of the valve body, and even if the inner wall of the valve tube is bonded, it can be easily opened. Pipeline deformation has no obvious radial seal effect on the sealing performance of the valve body. The symmetry of the sealing surface of the valve body of this structure is required to be relatively high, especially the sloping plate structure whose valve body sealing side plane is difficult to process on ordinary mechanical equipment, and a reasonable process must be arranged in order to make the assembly precision achieve the desired sealing effect. If the plane seal structure is a lever type, both the vertical plate and the inclined plate structure can solve the problem of the sealing plane in the processing process. This structure has many advantages. The valve sealing surface of the lever structure is a side plane seal and does not generate radial jamming. In addition, the flat surfaces of the valve body and the butterfly plate are processed in a continuous plane and the outer diameter of the butterfly plate is smaller than the diameter of the valve body. When the butterfly plate is closed, the translational sealing surface is pressed more and more tightly. During the opening process, the butterfly plate is rotated and then rotated, and no jamming occurs. Flue-butterfly valves generally work under low pressure and high temperature conditions and do not affect the opening and closing of valves.