What is the American standard cut-off valve

Cut-off valve is the most widely used type of cut-off valve in chemical production. Compared with the aforementioned cut-off valve, it does not use the rotation of its closing parts to open and close the valve, but USES the lifting of the valve stem to drive the circular disc (valve head) connected to it, changing the distance between the disc and the seat to reach the starting and closing of the control valve. Streamline type globe valve American standard type globe valve features: by the upper handwheel, stem, central thread and stuffing box sealing section, small on the valve stem threads in the valve body, its structure is compact, but the stem part of contact with the medium, and more particularly threaded portion is easy corrosion, judging from the stem above the height of the valve cover valve open degree, to prevent medium along the valve stem leakage, can wear out in stem cover parts with packing seal. The globe valve structure is complex, but the operation is simple, not very laborious, easy to adjust the flow rate and cut off the channel, the opening and closing slowly without water hammer phenomenon, so it is widely used. In the installation of globe valve, attention should be paid to the direction of flow. The pipeline fluid should flow from bottom to top through the seat port, and the so-called "low inlet height". The purpose is to reduce the fluid resistance, so that the stem and stuffing box are not in contact with the media in the opening and closing state, so as to ensure that the stem and stuffing box are not damaged and leaking. Globe valves are mainly used for pipes of water, steam, compressed air and all kinds of materials. They can regulate flow more accurately and cut off channels strictly.