the hydraulic servo proportional system in the control process of the large BF Abstract

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 This paper discuss the exact fabric of the modern, large-scale blast furnace, revealing the importance of the precision control of material flow control valve, and large-scale blast furnace feed flow control valve the status quo, the use of the proportional system of hydraulic servo control of the feasibility of the material flow control valve and control principle described in detail, brief introduction to the practical application of the results in a large blast furnace.


Keywords: BF material flow control valve hydraulic servo and proportional systems
PID meter/">regulator γ angle

First, an overview

With the rapid development of the metallurgical industry as an important part in the iron and steel smelting process - the blast furnace also produced several major changes. From the small blast furnace of 100 m 3 to 300 m 3 to the 1750 m 3,3800 m 3 or even to 4200 m 3 large blast furnaces, from the initial double bell-less top has now been commonly used in bell -less top, no material bell-less top structure is also divided into string tank and tank, and so on. Now the bell-less top several forms of BT type, PW type, SS type.sae hydraulic fittings

Second, the bell-less top exact fabric principle

Modern blast furnace smelting To maximize efficiency of the material flow control valve Gabe chute control to achieve the ore, coke in the furnace precise fabric, material flow control valve and chute control fabric principle shown in Figure and shown in Figure 2.



Blast furnace (sinter, pellets, or coke, etc.) after batching process under the slot first into the roof of the hopper and the hopper under the hopper the material flow control valve first process in the blast furnace after receipt of the fabric instructions requirements to open to a given opening (ie, gamma angle), Then charge at a certain flow through the fabric rol ler flow chute, the chute has been according to process requirements rise to a certain tilt angle (angle α) , while the chute is still on the horizontal direction of the uniform rotation (angle β). Such charge uniform cloth to the material surface of the blast furnace.

Can be seen from above The fundamental principle of the roof fabric, as long as the control of the good α, β, γ, three angles, and can charge by any form of cloth to the furnace. Generally speaking, the fabric of the blast furnace there are several forms of the ring fabric, fan-shaped fabric and designated fabric. The most frequently used is a circular fabric, ie, the number of materials with different tilting dynamic angle of cloth to the furnace, forming a number of ring furnace center of a circle, so that charge uniform cloth in the furnace. Divided into single-loop fabric and a ring of cloth according to how much of the annular fabric ring, the most commonly used for the link to the City of Victoria fabric. You can take advantage of the fan-shaped fabric or fixed-point fabric to make up for the uneven surface of the furnace material in the smelting process. Or the furnace furnace conditions need to improve the permeability, to protect the furnace wall temperature without overheating reasons, also need a fan or fixed-point fabric to improve the distribution of the furnace charge.

Control of the roof fabric, under the hopper the material flow control valve opening degree control (ie control) of the γ angle is critical, because the γ angle control accuracy in order to effectively control the flow of the cutting material, thus more accurately control the start and end of each batch of material thickness of the fabric, the number of rings and fabric.

Material flow control valve control status

No bell furnace top, the material flow control valve control There are basically three kinds:

A normal motor and gear reduction mechanism to control the material flow control valve opening degree. In this way control equipment is simple, but the accuracy is hard to improve the system operating time is longer, not conducive to improving the rhythm of the blast furnace production. In addition, the mechanical clearance in the gear reducer in the accuracy of the γ angle is also very difficult to eliminate, so do not use this control in a large blast furnace on basic.

2, the use of servo motor-driven material flow control valve. Driven approach can better guarantee the accuracy of the gamma angle, but the drive torque subject to certain restrictions, another of its action rather long time, not conducive to improving the production rhythm, generally used more often in the 450 meters and below the blast furnace.

3, the hydraulic system to drive the material flow control valve. This is a w ay of the biggest advantages is the drive torque can make the system operating time is significantly shortened, In addition, the control is relatively simple, using two conventional pilot-operated check valve to control the opening of the hydraulic cylinder, and thus to control γ angle of opening of purpose shown in Figure 3. The general large-scale blast furnace is mostly in this way.


A valve hydraulic control one-way valve, 3 way flow control valves 4 fuel tanks

Three ordinary hydraulic system to control material flow valve schematic

However, the disadvantage of this approach is obvious. One is the ordinary hydraulic system to control the hydraulic cylinder, its thrust by the system pressure is relatively large, easy to form the impact on the life of the material flow valve has a certain impact; next is more important, its accura cy is difficult to control, which material flow valve in the open to a given angle, which is full of charge, for once in place can not be repeated adjustment, while the normal hydraulic system can not meet this requirement. The use of the hydraulic cylinder positioning accuracy error is relatively large, generally 1.5 to 2.0 degrees, and sometimes actually reach 2.5 to 3.5 degrees. So that the accuracy of large-grained material in the blast furnace cloth (such as sinter or coke) when more than 20mm may affect not too serious, but in need cloth of fine granular material, in particular, is less than 5mm crushing or broken coke. it is difficult to control and can not even control.

Fourth, the proportion of hydraulic servo system controls the material flow control valve feasibility

For these reasons, in the large-scale blast furnace, if they can take full advantage of the hydraulic system thrust, fast action, but also to maximize the elimination of the impa ct of changes in system pressure thrust, reducing the impact of the mechanical system, while the control accuracy a substantial increase, it is ideal, but

Based on the above ideas, we used on the # 1 1750 m 3 blast furnace, an iron works of Jinan Iron and Steel with hydraulic servo proportional control system instead of the original ordinary hydraulic system to control material flow control valve to obtain the desired results.