In large-scale air separation industry, engineers tend to use three lever valves instead of butterfly valves. Why butterfly valves are rarely used in air separation? Here are the reasons:

1. During the opening and closing process of the butterfly valve, there is friction between the valve disc and the sealing ring, which can easily cause wear of the sealing ring, leading to leakage.

2. The self-weight of the large-diameter butterfly valve disc cannot be overcome: if installed vertically, the stopper will wear and the valve plate will sink, aggravating the wear of the sealing surface. If installed horizontally, the bearings will wear out, which may cause the valve plate to sink in some cases, or cause the valve stem and bearings to become stuck in severe cases.

3. If the butterfly valve is installed vertically, impurities inside the pipe can easily enter the gap between the lower valve stem and the bearing, which may cause the valve to jam.

4. Large-diameter butterfly valves need to be removed from the pipeline for maintenance, which requires a large workload and requires long downtime.

Why use three lever valve?

1. The valve plate and valve seat move in translation when they are initially opened (disengaged) and closed, and there is no shearing, extrusion, or friction on the valve seat, so it is reliable and has a long service life.

2. The valve seat seal is located on the vertical surface. During the switching process, the valve seat sealing surface will not be damaged by solid particles remaining in the pipeline - that is, it has a self-cleaning function.

3. It has the maximum opening pressure difference protection to effectively prevent the punching of molecular sieves.

4. The flow capacity is smaller than that of butterfly valve.