The opening and closing parts of the globe valve are plug-shaped discs, the sealing surface is flat or conical, and the disc moves linearly along the center line of the fluid. The movement form of the valve stem includes a lifting rod type (the valve stem rises and falls, and the handwheel does not rise and fall), and there is also a lifting rotating rod type (the handwheel rotates and lifts together with the valve rod, and the nut is arranged on the valve body). The globe valve is only suitable for fully open and fully closed, no adjustment and throttling are allowed.

The globe 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 under the valve disc, the resistance that the operating force needs to overcome is the friction force 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 stem The diameter of the valve should be large, otherwise the failure of the top of the valve stem will occur. In recent years, since the emergence of self-sealing valves, the medium flow direction of the globe valve has been changed from the top of the valve disc into the valve cavity. At this time, under the action of the medium pressure, the force to close the valve is small, while the force to open the valve is large, and the valve stem's force is small. The diameter can be reduced accordingly. At the same time, under the action of the medium, this form of valve is also tighter. my country's valve "Three Chemicals" once stipulated that the flow direction of the globe valve should be from top to bottom.

When the globe valve is opened, when the opening height of the valve disc is 25% to 30% of the nominal diameter, the flow rate has reached a large value, indicating that the valve has reached the fully open position. Therefore, the fully open position of the globe valve should be determined by the stroke of the valve disc.

Globe valves have the following advantages:

 1. Simple structure, easy to manufacture and maintain.

 2. The working stroke is small and the opening and closing time is short.

 3. Good sealing performance, small friction between sealing surfaces and long service life.

The disadvantages of globe valves are as follows:

 1. The fluid resistance is large, and the force required for opening and closing is large.

 2. It is not suitable for medium with particles, high viscosity and easy coking.

 3. Poor adjustment performance.

 4. The types of globe valves are divided into external thread type and internal thread type according to the position of the valve stem thread. According to the flow direction of the medium, there are straight-through type, direct-current type and angle type. The globe valve is divided into sealing form, including packing seal globe valve and bellows seal globe valve.

The main features of the PE/PRR pipe production line are its compact structure, reliable sealing, simple structure and convenient maintenance. Natural gas and other general working media, but also suitable for media with harsh working conditions, such as oxygen, hydrogen peroxide, methane and ethylene, etc., and are widely used in various industries. The ball valve body can be integral or combined.

Ball valves have the following advantages:

1. The fluid resistance is small, and the full-bore ball valve basically has no flow resistance.

2. Simple structure, small size and light weight.

3. Tight and reliable. It has two sealing surfaces, and various plastics are widely used for the sealing surface materials of the ball valve at present, which has good sealing performance and can achieve complete sealing. It has also been widely used in vacuum systems.

4. Easy to operate, quick to open and close, only need to rotate 90° from fully open to fully closed, which is convenient for long-distance control.

5. The maintenance is convenient, the ball valve has a simple structure, the sealing ring is generally movable, and it is more convenient to disassemble and replace.

6. When fully open or fully closed, the sealing surfaces of the ball and the valve seat are isolated from the medium, and when the medium passes through, the valve sealing surface will not be eroded.

7. It has a wide range of applications, with diameters ranging from small to several millimeters to several meters, and can be applied from high vacuum to high pressure.

8. Since the ball valve has wiping properties during the opening and closing process, it can be used in media with suspended solid particles.