How is the plug valve distinguished?

We all know that the plug valve is divided into: tight plug valve, packing plug valve, self-sealing plug valve and other forms.
How to distinguish the structural form of the plug valve?
Let’s talk about different forms of plug valves:
1. Tightened plug valve: The plug valve has no packing, and the sealing between the plug and the sealing surface of the plug body is realized by tightening the nut under the plug valve. Generally used for pipelines with nominal pressure PN≤0.6MPa.
2. Packing plug valve: The plug valve body has packing, and the sealing surface of the plug and the plug body is sealed by pressing the packing. The packing type plug valve has better sealing performance and is widely used in the occasions where the nominal pressure is PN1.0MPa; the screw under the plug body It can play the role of adjusting the tightness of the plug and the plug body.
3. Self-sealing plug valve: The sealing between the plug and the plug body of the plug valve is mainly realized by the pressure of the medium itself; the self-sealing plug valve is generally used for air medium. The spring under the self-sealing plug valve structure can play the role of preload and compression.
Of course, there is also a plug valve which is an oil-filled plug valve. It adopts forced lubrication to form an oil film between the plug valve plug and the sealing surface of the plug body, which provides the sealing performance of the plug valve and saves effort when opening and closing the plug valve. Prevent damage to the plug valve sealing surface.