What operating conditions require the selection of shut-off valves

Stop valve is one of the widely used valves, and its popularity is due to the low friction between sealing surfaces during the opening and closing process, its durability, small opening height, easy manufacturing, and convenient maintenance. It is not only suitable for medium and low pressure, but also for high pressure. The closing principle of a shut-off valve is to rely on the pressure of the valve stem to tightly fit the sealing surface of the valve disc and the sealing surface of the valve seat, preventing the flow of medium. It can be used to control the flow of various types of fluids such as air, water, steam, various corrosive media, mud, oil products, liquid metals, and radioactive media. Therefore, this type of shut-off valve is very suitable for cutting, regulating, and throttling purposes. Due to the relatively short opening or closing stroke of the valve stem and the highly reliable cut-off function, as well as the proportional relationship between the change of the valve seat opening and the stroke of the valve disc, this type of valve is very suitable for regulating flow.

The stem axis of the shut-off valve is perpendicular to the sealing surface of the valve seat. The opening or closing stroke of the valve stem is relatively short and has a very reliable cut-off action, making this valve very suitable for cutting, adjusting, and throttling the medium.

Once the valve disc of a shut-off valve is in an open state, there is no longer contact between its seat and the sealing surface of the valve disc, and it has a very reliable cut-off action. This valve is very suitable for cutting, adjusting, and throttling as a medium.

Once a shut-off valve is in an open state, there is no longer contact between its seat and the sealing surface of the valve disc, resulting in less mechanical wear on its sealing surface. Due to the ease of repairing or replacing sealing components for most shut-off valves, the entire valve does not need to be removed from the pipeline. This is very suitable for situations where the valve and pipeline are welded together. When the medium passes through such valves, the flow direction changes, so the flow resistance of the shut-off valve is higher than that of other valves.

There are several commonly used globe valves:

1. Angle globe valve; In angle globe valves, the fluid only needs to change direction once, so that the pressure drop through this valve is smaller than that of conventional globe valves.

2. Direct flow shut-off valve; In direct flow or Y-shaped globe valves, the flow path of the valve body is inclined with the main flow path, which reduces the degree of damage to the flow state compared to conventional globe valves, and therefore reduces the pressure loss through the valve.

3. Plunger type globe valve: This form of globe valve is a variant of a conventional globe valve. In this valve, the disc and seat are usually designed based on the plunger principle. The valve disc is polished into a plunger and connected to the valve stem, and the sealing is achieved by two elastic sealing rings sleeved on the plunger. Two elastic sealing rings are separated by a sleeve ring and the sealing ring around the plunger is pressed firmly by the load applied by the valve cover nut on the valve cover. The elastic sealing ring can be replaced and can be made of various materials. The valve is mainly used for "opening" or "closing", but it is equipped with a special form of plunger or special collar, which can also be used to regulate flow.