Butterfly valve and ball valve difference

Butterfly valve definition: Butterfly valve (English: butterfly valve) refers to the closure (valve or disc) for the disc, rotating around the valve shaft to achieve a valve on and off, mainly in the pipeline cut off and throttling purposes. Butterfly valve opening and closing pieces is a disc-shaped disc, the valve body around its own axis of rotation, so as to achieve the purpose of opening and closing or regulation. The butterfly valve fully open to the whole is usually less than 90 °, the butterfly valve and the butterfly itself does not have self-locking ability, in order to disc positioning, to install a worm reducer on the stem. The use of worm reducer, not only can make the disc self-locking ability to stop the butterfly plate in any position, but also to improve valve performance. Industrial butterfly valve features high temperature, high pressure range, the valve nominal diameter, the valve body made of carbon steel, the valve ring using a metal ring instead of rubber ring. Large high temperature butterfly valve welded steel manufacturing, mainly for high temperature medium smoke duct and gas pipelines. Definition of ball valve: Ball valve, GB / T21465-2008 "Valve term" is defined as: Opening and closing pieces (ball) by the valve stem and the valve stem for the axis of rotation. Mainly used to cut off or connect the medium in the pipeline, can also be used for fluid regulation and control, in which the V-shaped ball valve hard seal its V-shaped core with hard metal welding seat metal seat has a strong shear Shear, especially for containing fibers, small solid particles and other media. The multi-pass ball valve in the pipeline can not only flexibly control the merging of media, diversion, and flow switching, but also can close any channel and the other two channels connected. The main features of the ball valve is its compact structure, the seal can be *, simple structure, easy maintenance, sealing surface and the spherical surface is often closed, easy to be media erosion, easy to operate and repair, suitable for water, solvents, acids and natural gas Working medium, but also for poor working conditions of media, such as oxygen, hydrogen peroxide, methane and ethylene, etc., are widely used in various industries. Ball valve body can be a whole, it can be combined. The difference between the two: the biggest difference between the two is that the butterfly valve opening and closing pieces is a plate, and the ball valve is a ball. Butterfly valve plate and ball valve spool are rotating around their own axis of movement; gate valve plate is along Axis for lifting movements; butterfly valve and gate valve can be adjusted by the opening degree of flow; ball valve is not easy to do this. Ball valve sealing surface is spherical, butterfly valve sealing surface is a circular cylindrical surface. Butterfly valve is characterized by quick opening and closing speed, simple structure, low cost, but the tightness and pressure capacity is not good. The characteristics of the ball valve and valve similar, but by the volume and opening and closing resistance constraints, it is difficult to achieve large diameter. The structural principle of the butterfly valve is particularly suitable for the production of large-diameter butterfly valve butterfly valve installed in the diameter direction of the pipe. In the butterfly valve body cylindrical channel, the disc-shaped disc rotates about the axis, the rotation angle is between 0 ° ~ 90 °, when rotated to 90 °, the valve is fully open state card. Its simple structure, low cost, adjustable range larger. Ball valves are generally suitable for liquids and gases with no particulate impurities, low fluid pressure loss, good sealing performance and high cost. In comparison, the ball valve seal better than the butterfly valve. Ball valve seal is * Seat long-term squeeze on the spherical, it certainly wear faster than the half-ball valve, the ball valve seal is usually flexible materials, it is difficult to use in high temperature and pressure pipe. Butterfly valve seal is rubber-based, it is far more than the semi-spherical valve, ball valve, gate valve metal seal performance. After long-term use of the semi-spherical valve, the valve seat will also produce a slight wear, it can be adjusted to continue to use, the stem and packing valve stem rotation during opening and closing only 90 °, there are signs of leakage, and then compress the packing gland Bolt a little, you can achieve no leakage at the packing, and other valves are still a small leak barely used, a large leak valve. Ball valve during opening and closing process by the valve seat at both ends of the holding force under the operation, it is larger than the half-ball valve opening and closing torque, the larger the nominal diameter opening and closing torque difference more obvious, the valve opening and closing is to overcome the deformation of the rubber To achieve more torque. The gate valve, globe valve operating time is long and strenuous. Ball valve and plug valve are of the same type of valve, and only its closure is a sphere, the sphere around the centerline of the valve body to rotate to achieve open, close a valve. Ball valve is mainly used in the pipeline to cut off, distribute and change the flow direction of the medium.