Analysis Of The Sealing Form And Technical Requirements Of Stainless Steel Ball Valves

2 Piece Ball Valve The form of the main sealing structure, the choice of sealing materials and other factors that affect the sealing performance, performance and reliability of the ball valve. At present, the main structural form of the combined sealing seat composed of elastic expansion ring and polytetrafluoroethylene lip sealing seat is used on stainless steel ball valves. Stainless steel ball valves are widely used in various pipeline systems for rapid cutting, changing the flow direction of the medium and automatic control, and can be driven manually, electrically or pneumatically.

The sealing structure of the stainless steel ball valve is mainly composed of three parts. The first is the seal between the main and auxiliary valve bodies, which is realized by the sealing adjustment gasket; the second is the seal between the main valve body and the valve stem, which is realized by the standard "V"-shaped packing or O-shaped sealing ring, forming the external sealing structure of the ball valve. The third is the seal between the ball and the main and auxiliary valve bodies, which is realized by the sealing seat, forming the main sealing structure of the ball valve. The sealing of the main sealing structure affects the working performance of the ball valve and is a key sealing structure in the design and manufacture of the ball valve.

The following points focus on the non-metallic seal (also known as soft seal) structure of the main seal of the ball valve.
1) Sealing requirements of ball valves: The national standard stipulates that the sealing of non-metallic sealed ball valves shall be implemented according to Class A of GB/T13927 "General Valve Pressure Test";
2) The main factors affecting the sealing of stainless steel ball valves are the roughness of the sealing surface and the roundness parameters of the ball body;
3) The main sealing structure of the ball valve adopts a combined sealing seat composed of an elastic expansion ring and a polytetrafluoroethylene lip seal seat. It can rely on the good elastic-plastic deformation ability of the metal material elastic expansion ring to enhance its overall elastic-plastic deformation ability and compensation ability, and improve the sealing ability of the ball valve; a sealing seat with an elastic element is used. The acquisition and adjustment of the pre-compression amount no longer rely on the sealing adjustment gasket but are achieved by the elastic element. In addition to obtaining the necessary pre-compression amount, the sealing seat with an elastic element can also compensate for the pre-tightening specific pressure within the elastic deformation range of the elastic element, and the service life of the stainless steel ball valve is relatively long.