How to select the manual lever butterfly valve and worm gear box operated butterfly valve-Belo Valve

Before we figure out how to select the manual lever butterfly valve and worm gear operated butterfly valve, we should first need to understand how the manual lever butterfly valve and worm gear box operated butterfly valve works. The manual lever butterfly valve is using the lever handle to rotate the valve stem directly to achieve the opening and closing of the butterfly valve, while the worm gear box operated butterfly valve is using the worm gear reducer box to open and close the butterfly valve. With the application of worm gear box in butterfly valve, the butterfly valve is easy and labor saving to be operated. For the butterfly valve with small diameter, usually the lever handle is used, while for the butterfly valve with nominal diameter is over 200mm, usually the worm gear box is used to operate the butterfly valve. 

Manual lever butterfly valve and worm gear box operated butterfly valve belong to two different kinds of butterfly valves. They have different operating principles. But their working principles are almost the same( opening and closing through rotating of valve disc with 90°）. in order to decide which kind of butterfly valve should be used, manual lever butterfly valve or worm gear box operated butterfly valve, you should consider the technical parameters of the butterfly valve required, the working conditions, and your purchasing cost. Usually the worm gear box operated butterfly valve is more easy and labor saving to operate, and its cost is relatively higher than that of the lever handle butterfly valves. Lever handle butterfly valve and worm gear box operated butterfly valves are both called manual butterfly valves. 

How to decide which type of manual butterfly valve should be used? Manual lever butterfly valve or worm gear box operated butterfly valve? 

Due to the limitations of the lever handle butterfly valve itself, the lever handle butterfly valves can only be used in pipelines with nominal diameter less than 200mm, and also lever handle can only be used to operate the concentric resilient seated soft sealing butterfly valves. The advantage of lever handle butterfly valve is that it has great sealing performance, and can achieve zero leakage, while lever handle butterfly valve is not suitable for metal hard sealing butterfly valves. 

Different from handle lever soft sealing butterfly valves, metal hard sealing butterfly valves are widely used for high temperature, high pressure pipelines, it is difficult to operate with lever handle, that’s why the worm gear box is usually used for metal hard sealing butterfly valves. We know that, the lever handle butterfly valve can be used in small diameter pipelines, while worm gear box operated butterfly valves can also be used in small diameter pipelines. But worm gear box operated butterfly valves can also be used in large diameter pipelines. 

So if you want to choose a butterfly valve for small diameter pipelines(DN≤200mm), and your cost is limit, lever handle butterfly valve is a better selection. But if you want to choose a butterfly valve for large diameter pipelines(DN＞200mm), worm gear box operated butterfly valve is a must. 

If you still have no idea what kind of butterfly valves should be used in your pipeline systems, kindly contact us, professional and proper advice will be offered: