Some parts, joints and high pressure valves of the gas pipeline are collectively referred to as instrument high pressure ball valves. The stability of the instrument high pressure ball valve directly determines the consumption and wear of the instrument, and it will also be affected in chemical production. Poor stability of the instrument high pressure ball valve will cause the accuracy of the instrument to fall, but also make the maintenance of the instrument to increase, these problems are the instrument operators do not want to encounter problems.

    The connection methods of high and middle pressure ball valves include: flange connection, clamp connection, butt welding connection, thread connection, sleeve connection, clamp connection, self-sealing connection and other connection forms.

    Flange connection:

    The flange connection is a valve body with flanges at both ends, corresponding to the flange on the pipe, and is installed in the pipe by bolting the flange. Flange connection is the most commonly used connection form of valves. Flange has convex (RF), plane (FF), convex and concave (MF), etc.

    Clamp connection:

    The high pressure valve is installed in the middle of the two flanges, the valve body is usually equipped with positioning holes to facilitate installation and positioning, and the high pressure valve and the two pipes are directly connected by bolts.

    Welded connection:

    It is also divided into butt welding connection and socket welding connection, butt welding connection: both ends of the valve body are processed into butt welding groove according to the butt welding requirements, corresponding to the pipe welding groove, and are fixed on the pipe by welding; Socket welding connection: Both ends of the valve body are processed according to socket welding requirements and connected to the pipeline through socket welding.

    Threaded connection:

    Threaded connection is a simple connection method, often used in small high and medium pressure valves. The valve body is processed according to the standard of each thread, there are two kinds of internal thread and external thread. Corresponds to the pipe upper thread.

    Sleeve connection:

    Sleeve connection, only developed in China in recent years, its connection and sealing principle is that when the nut is tightened, the sleeve is under pressure, so that its edge bites into the outer wall of the pipe, and the outer cone of the sleeve is tightly closed with the cone of the joint body under pressure, so it can reliably prevent leakage. Such as high school pressure ball valve.

    Clamp connection:

    This is a fast connection method that requires only two bolts and is suitable for high pressure valves that are often removed. Such as sanitary high pressure valve.

    Internal self-tightening connection:

    All of the above connection forms use external forces to offset the pressure of the medium to achieve sealing. The following describes the form of self-tightening connection using medium pressure. Its sealing ring is installed in the inner cone, with the opposite side of the medium at a certain Angle, the medium pressure is transmitted to the inner cone, and is transmitted to the sealing ring, on the cone of a certain Angle, two components are generated, one is parallel to the center line of the valve body, and the other is pressed to the inner wall of the valve body. The latter component is the self-tightening force. The greater the medium pressure, the greater the self-tightening force. Therefore, this connection form is suitable for high pressure valves. It is more than the flange connection, to save a lot of materials and manpower, but also requires a certain preload force, so that when the pressure in the valve is not high, the use of reliable.