Structural characteristics, installation and maintenance of Bellows globe valve

Bellows globe valve eliminates the problem of stem packing seal leakage and meets the requirements of serious leakage level. 
If the bellows unfortunately fails, the packing seal on the valve stem can provide secondary seal to prevent leakage. 
Maintenance-free. 
Bellows seal structure not only put an end to leakage, but also without maintenance, such as the need to replace internal parts, convenient, simple, fast, all parts up to the standard, interchangeable. 
Fatliquoring and oiling. 
There is a fatliquoring hole in the bonnet / bonnet to lubricate the stem and nut sleeve. 
Spherical conical valve core. 
Bellows globe valve adopts unique spherical cone valve core instead of traditional plane valve core, which can be roughly controlled manually, valve core surface hardening treatment, improve sealing performance, below DN150 and vertical installation, valve core self-adjustment. 

Structural characteristics of bellows globe valve: 

1. The valve body and bonnet are connected by double stud with simple structure and good technological performance. 
2. The valve stem of this valve not only has the filling letter of the general valve, but also in the lower part of the filling letter, the upper part of the valve cavity is equipped with a movable sealing element-stainless steel bellows, and the medium is sealed in the valve cavity outside the stem and cannot enter the filling letter. Therefore, this valve is more reliable than the general valve in preventing leakage, ensuring the sealing of the connection between the stem and the bonnet. 
3. Valve stem nut adopts surface nitriding to improve surface hardness and wear resistance and prevent occlusal phenomenon. 
4. Medium flange bolts are made of high strength alloy steel with excellent high temperature creep resistance, safety and reliability. 
5. The bellows is designed in the inner cavity of the bonnet to avoid direct erosion with the medium and improve the service life of the bellows. 
6. The bellows adopts 2 to 4 times overlap to prevent valve leakage due to single layer damage of bellows and prolong the service life of the valve. 
7. Because the bellows design is relatively long, the opening height is large, the main resistance of the fluid is reduced, and the flow resistance coefficient is small. 
8. Double seal of packing and bellows is adopted to achieve zero leakage. 

The installation and maintenance of bellows globe valve should pay attention to the following matters: 

1. The bellows cutoff valve operated by handwheel and handle can be installed in any position of the pipe. 
2. Handwheels, handles and large motion mechanisms are not allowed to be used for lifting. 
3. The flow direction of the medium should be consistent with the direction of the arrow shown by the valve body.