Cast steel globe valve is one of the most widely used valves. The reason why it is popular is that the friction between the sealing surfaces is small during the opening and closing process, which is more durable, the opening height is not large, easy to manufacture, and convenient to maintain, not only suitable for medium and low pressure, but also for high pressure.
The closing principle of the cast steel globe valve is that relying on the pressure of the valve stem, the sealing surface of the disc and the sealing surface of the valve seat are closely fitted to prevent the flow of the medium.
Ⅰ. Structures of the cast steel globe valve
The length is longer than that of the gate valve, the fluid resistance is large, and the sealing reliability is not strong during long-term operation.
As one of the most important shut-off valves, the cast steel globe valve plays an important role in the aerospace field. As an important component of aerospace equipment, the cast steel globe valve realizes the functions of medium transportation, cutoff and adjustment, and its sealing performance directly affects the safe and reliable operation of aerospace equipment.
The study of the influencing factors and rules of the sealing characteristics of typical cast steel globe valves has guiding significance for the structural design of the valve sealing pair, thereby improving the sealing performance and reliability of the valve.
Ⅱ. What is the selection standard of the cast steel globe valve?
- Cast steel globe valves should be selected for pipelines or devices of high temperature and high-pressure medium. For example, cast steel globe valves are suitable for high temperature and high-pressure pipelines of thermal power plants and petrochemical systems;
- On the pipeline where the convection resistance requirements are not strict, that is, the place where the pressure loss is not considered;
- Cast steel globe valves can be selected for small valves, such as needle valves, instrument valves, sampling valves, pressure gauge valves, etc.;
- There is flow adjustment or pressure adjustment, but the requirements for adjustment accuracy are not high, and the diameter of the pipeline is relatively small. For example, on the pipeline with a nominal diameter of ≤ 50mm, a cast steel globe valve or throttle valve should be used;
- For water supply and heating projects in urban construction, for pipelines with smaller nominal diameters, cast steel globe valves, balance valves or plunger valves can be applied, such as pipelines with a nominal diameter less than 150mm;
- Applicable to medium pipelines such as steam below DN200;
- Not suitable for medium with high viscosity;
- Not suitable for media containing particles that are easy to precipitate;
- It is not suitable for vent valve and valve of low vacuum system.
