The opening and closing part of the angle globe valve is a plug-shaped valve disc, the sealing surface is a plane or a conical surface, and the valve disc moves linearly along the center line of the fluid. The movement form of the valve stem includes a lifting rod type and a lifting rotating rod type. The bellows globe valve is only suitable for fully open and fully closed, no adjustment and throttling are allowed.
Working Principle:
The thermal insulation 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 from below 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 The diameter should be large, otherwise the failure of the top of the valve stem will occur. After the appearance of the self-sealing valve, the medium flow direction of the globe valve is 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, but the force to open the valve is large, and the diameter of the valve stem can be adjusted accordingly. decrease. At the same time, under the action of the medium, this form of valve is also tighter. my country stipulates that the flow direction of the globe valve shall be from top to bottom.
Operation Note:
1. When the angle-type globe valve is opened, when the opening height of the 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.
2. The types of liquefied gas stop 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.
3. Installation and maintenance of angle type globe valve Handwheel and handle-operated bellows globe valve can be installed in any position of the pipeline.
4. The handwheel, handle and transmission mechanism are not allowed to be used for lifting.
5. The flow direction of the medium should be in the same direction as the arrow shown on the valve body.
6. High temperature and high pressure globe valve, also known as valve, is a widely used valve. The reason why it is popular is that the friction between the sealing surfaces during the opening and closing process is small, it is more durable, the opening height is not large, and it is easy to manufacture. , easy maintenance, not only suitable for medium and low pressure, but also suitable for high pressure. Its closing principle is that relying on the pressure of the valve stem, the sealing surface of the valve disc and the sealing surface of the valve seat are closely fitted to prevent the flow of the medium.
7. The insulation shut-off valve only allows the medium to flow in one direction, and has directionality during installation. Its structural length is longer than that of the gate valve, and at the same time, the fluid resistance is large, and the sealing reliability is not strong during long-term operation.
