Regarding the orientation of the stop valve
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It turned out that the flow direction of the globe valves I had seen before was always from low to high; now, however, the flow direction of many globe valves is from high to low； The high-in-low-out stop valve is used in gas pipelines with high pressure, as well as those containing toxic or harmful gases, to improve airtightness and prevent leaks ； Is there anyone who knows a lot about this area? Please share your experience. If there are any relevant standards, could you let me know which ones they are? Thank you!
It seems that the pressure regulating valve operates with high inlet and low outlet pressure, indicated by arrows
Small-diameter valves generally operate with low inlet pressure and high outlet pressure. The main reason for this is to prevent the packing from being under pressure for extended periods of time, thereby extending its service life; it also provides some protection for the valve stem. Most importantly, it ensures safety – if the valve stem breaks or some other fault occurs, the valve can open automatically to prevent the system from experiencing overpressure. Large-diameter valves use a high-inlet and low-outlet design; this is due to considerations related to the required operating force and sealing issues. If a low-inlet and high-outlet design were used, it would be difficult to address these problems related to operating force and sealing, and the diameter of the valve stem would increase as well, making the valve heavier and hindering efforts to reduce its weight.
Having seen several types of installations, the design with check valves that allow flow from high to low pressure has become popular in recent years, especially in high-pressure hydrogenation units. As mentioned above, some imported valves are designed in this way; many valves with self-sealing features that permit flow from high to low pressure can enhance the sealing effect. It also makes it easier to shut off the check valves in emergency situations, as less force is required for closure. There is no specific official standard for this.
The direction of flow for the valve is specified, so simply install it according to the markings on the valve. Design and manufacturing take safety, sealing performance, operational performance, etc., into account; each has its advantages and disadvantages
To prevent high voltage from leaking into the low voltage side, the high voltage end corresponds to the upper part of the shut-off valve, while the low voltage end corresponds to the lower part of the shut-off valve. Generally, installation should follow the principle of low entry and high exit
It is recommended to install it in the direction indicated by the arrow on the valve body