Introduction of Bellows Sealed Ball Valve
1 overview
Bellows-sealed valves are mainly used in harsh occasions with flammable, explosive and toxic conditions. The dual functions of packing and bellows achieve valve stem sealing, achieving zero leakage between the valve and the outside world. Because the bellows can only withstand tension and pressure, it is only suitable for valves whose stem moves linearly during the opening and closing process, so bellows valves are generally limited to globe valves or gate valves. In order to make the principle of bellows seal more widely used, the bellows seal ball valve has been developed.
2 structure
The bellows-sealed ball valve is mainly composed of a valve body, an upper valve stem, a valve stem, a bellows, a lower valve stem and a pin. A pair of spiral track grooves (the same spiral direction) are opened on the upper and lower valve stems. The two pins are fixed on the valve stem and the pins can move freely in the track grooves of the upper and lower valve stems. The lower stem and the ball are connected to control the opening and closing of the valve.
3 working principle
When the upper valve stem rotates, the pin installed on the valve stem tends to rotate, but the lower spiral groove of the valve stem and the upper spiral groove have the same rotation direction, which will exert a reverse force to hinder its movement. According to the analysis of the force balance principle, the valve stem will only move up and down under the action of the spiral groove. Because the bellows is welded to the valve stem, the lifting of the valve stem ensures the safety of the bellows.
4 Conclusion
The bellows-sealed ball valve is a relatively novel structure, which effectively solves the problem of the bellows rotating in the ball valve sealing process. It uses two spiral grooves with the same rotation direction to make the external force pass three times in the process of transmission. Conversion. The two spiral grooves have the same direction of rotation, which is easy to process and does not require configuration during assembly, which effectively meets the requirements of modern valves for convenient processing, simple assembly, reliable work, and safe operation.
Nortech is one of the leading industrial valve manufacturers in China with quality certification ISO9001.
Major products: Butterfly Valve, Ball Valve,Gate Valve, Check Valve, Globe Vavlve,Y-Strainers, Electric Acurator , Pneumatic Acurators .
Post time: Oct-18-2021