Issue with the orientation of the steam control valve?
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Should the steam control valve have low inlet and high outlet, or high inlet and low outlet? Steam stop valves all have flow from low to high, but among the steam control valves I’ve seen, some have flow from low to high while others have flow from high to low. Is there any standard for this? I appreciate your advice!
First, it is necessary to ensure that the flow direction indicated on the valve matches the actual flow direction. As for whether it’s low in and high out or high in and low out, that is the issue of flow opening and flow closing. It features good self-cleaning performance due to the flow-out (low inlet, high outlet) mechanism, as well as excellent sealing performance when the flow is stopped.
Generally, valves are marked with the flow direction; changing this direction may result in the valve not being able to close properly or open properly. However, this situation occurs rarely, as the pressure rating is usually sufficient
1) When fluid flows from high to low, the valve stem is submerged in the medium when the valve is closed, which makes it susceptible to corrosion. 2) When fluid flows from low to high, considerable force is exerted on the valve stem when closing the valve, as pressure from the medium must be overcome; this makes it difficult to close the valve and can easily cause the valve stem to bend. Actually, both forms exist, but the more common one is low entry and high exit. The original poster might want to give it a try by doing some research – there could be surprises. Many people have discussed this topic; actually, there is no clear standard specifying why control valves should be designed with inlet at the lower level and outlet at the higher level. For sizes up to DN100, the inlet is usually at the lower level and the outlet at the higher level. In the valve industry both domestically and internationally, large-diameter valves are conventionally designed with the inlet at the higher level and the outlet at the lower level. Secondly, it also does not specify that valves of a certain size or larger should be designed with high inlet and low outlet. (Basically, those of DN125 and above, including DN125, are designed with high inlet and low outlet.) In check valves with high inlet and low outlet pressure, they are usually designed with double valve discs (also known as balanced valve discs). There are two reasons for this design: one is to prevent excessive pressure differences from occurring when the valve is opened or closed. Secondly, the stiffness of the valve must be taken into consideration. A high inlet and low outlet configuration has a significant impact on the valve; typically, for large-diameter globe valves that are not designed with a balanced valve disc seal to handle this configuration, it becomes very difficult to hold the medium in place.
Generally, in cases of large diameters and high pressures, there will be high inflow and low outflow! Considering the issue of sealing!
High-temperature and high-pressure control valves generally use a high-inlet and low-outlet design, with radiators or oil injection holes above the valve seat.
It should be low inlet and high outlet, which is determined by the structural requirements of the interior cavity of the stop valve. It refers to the flow of fluid into the valve, where it moves from low to high within the valve chamber before exiting the valve body. The valve disc is at the top of the valve chamber.
Generally, it’s low in entry but high in output.