The differences are as follows:
1. The opening and closing part of the stop valve (Globe Valve) is a plug-shaped valve disc, the sealing surface is flat or conical, and the valve disc is The centerline of the fluid moves in a straight line. The movement form of the valve stem includes the lifting rod type (the valve stem rises and falls, the handwheel does not rise and fall), and the lifting and rotating rod type (the handwheel and the valve stem rotate and rise together, and the nut is set on the valve body).
2. The stop valve has the following advantages: simple structure, convenient manufacturing and maintenance. The working stroke is small and the opening and closing time is short. Good sealing performance, small friction between sealing surfaces and long service life.
3. The disadvantages of the stop valve are as follows: The fluid resistance is large and the force required to open and close is large. Not suitable for media with particles, high viscosity, and easy coking. Adjustment performance is poor.
4. The main feature of the ball valve is that it has a compact structure, is easy to operate and maintain, and is suitable for general working media such as water, solvents, acids, and natural gas. It is also suitable for media with harsh working conditions, such as oxygen, Hydrogen peroxide, methane and ethylene, etc. The ball valve body can be integral or combined.
5. Ball valves are mainly used in pipelines to cut off, distribute and change the flow direction of media. The ball valve is a new type of valve that has been widely used in recent years. It has the following advantages:
The fluid resistance is small, and its resistance coefficient is equal to that of a pipe section of the same length. It has simple structure, small size and light weight. Tight and reliable, plastic is widely used as the sealing surface material of ball valves at present, with good sealing performance, and has also been widely used in vacuum systems. It is easy to operate and opens and closes quickly. It only needs to be rotated 90° from fully open to fully closed, which is convenient for long-distance control. It is easy to maintain. The ball valve has a simple structure and the sealing ring is generally movable, making it easy to disassemble and replace.
6. When fully open or fully closed, the sealing surfaces of the ball and valve seat are isolated from the medium. When the medium passes, it will not cause erosion of the valve sealing surface. ? It has a wide range of applications, with diameters ranging from a few millimeters to several meters, and can be applied from high vacuum to high pressure. Ball valves have been widely used in petroleum, chemical industry, power generation, papermaking, atomic energy, aviation, rocket and other departments, as well as in people's daily life.
Extended information:
The stop valve is only suitable for fully opening and fully closing, and adjustment and throttling are not allowed. The stop valve is a forced sealing valve, so when the valve is closed, pressure must be applied to the valve disc to force the sealing surface not to leak. When the medium enters the valve from below the valve disc, the resistance that the operating force needs to overcome is the friction between the valve stem and the packing and the thrust generated by the pressure of the medium. The force to close the valve is greater than the force to open the valve, so the valve The diameter of the stem must be large, otherwise the valve stem will bend.
The working principle of the ball valve is to rely on the rotating valve to open or block the valve. Ball valves are light on and off, small in size, can be made into large diameters, have reliable sealing, simple structure, and easy maintenance. The sealing surface and spherical surface are always in a closed state and are not easily eroded by the medium. They are widely used in various industries. The ball valve and the plug valve belong to the same type of valve, only its closing part is a ball, and the ball rotates around the center line of the valve body to open and close.
Reference materials: Globe valve-Baidu Encyclopedia
Ball valve-Baidu Encyclopedia