With the development of catalytic cracking energy recovery technology and the increase of the processing capacity of catalytic cracking unit, the casting performance of matching special regulating butterfly valve is required to be improved.It is required that the valve has large caliber, large output torque, high reliability and high control sensitivity, so as to ensure the safety, stability and long cycle operation of the device and recover as much energy as possible.Overseas high temperature butterfly valve early development, variety.However, the domestic starting late, after trial production, improvement and continuous development, domestic high temperature butterfly valve manufacturers, they produce high temperature butterfly valve performance indicators have reached a higher level.High temperature butterfly valve design at home and abroad, the main driving form is pneumatic and electro-hydraulic form, the current development direction is electro-hydraulic high temperature butterfly valve, pneumatic high temperature butterfly valve is gradually out of the use of the field, currently in use has been very few.
At present, the domestic design and manufacture of high temperature butterfly valve is still mostly a stepped seal structure.In recent years, in order to improve the response speed of the hot butterfly valve at the inlet of the flue gas machine, cut off the valve quickly and ensure the reliability of the long cycle operation, some improvements have been made in the body structure.
A. A hardfaced hardmetal wear bushing is added between the stem and disc hub to protect the exposed stem between the seat ring and disc from erosion by high-speed airflow.
B. The support shafts at both ends of the stem are replaced with high-temperature resistant silicified graphite plain bearings, which overcomes the disadvantage that the original rolling bearing is easy to cause stem jam due to the influence of high temperature or corrosion.