Issues with the stop valve?
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They told me again that for the globe valve, fluid enters from below and exits from above, it’s not symmetrical left and right, and the flow direction cannot be reversed. This image shows a pipe outlet on each side; how does a stop valve allow flow from below to above? How can one tell that it is imported, and how can it be ensured that the flow direction cannot be reversed?
Gate valves can be installed horizontally; generally, there is a flow direction indicator on the valve body, and it should be installed according to the flow direction of the medium
Stop valves designed and manufactured in accordance with GB/T12235 and BS1873 standards can have a configuration where fluid enters from below and exits from above, or where it enters from above and exits from below; however, those made in compliance with API623 standards all feature fluid entry from below and exit from above.
Stop valves designed and manufactured in accordance with GB/T12235 and BS1873 standards can have a configuration where fluid enters from below and exits from above, or where it enters from above and exits from below; however, those made in compliance with API623 standards all feature fluid entry from below and exit from above. The so-called high inlet and low outlet phenomenon is actually a measure taken due to an oversized diameter of the stop valve or excessive pressure, in order to prevent the valve stem from failing to close tightly when moved downward. In the high-inlow-out configuration, the inlet and outlet directions of the valve are reversed; when the valve stem is raised to open the valve disc, it is necessary to overcome the pressure exerted by the medium on the valve disc (in the low-inhigh-out configuration, it is necessary to overcome the force exerted by the medium on the valve disc when closing it). If the valve disc is too large, the pressure it has to withstand will also be high. Therefore, in high-inlow-out configurations, a structure with a smaller and a larger valve disc is generally used – the valve stem lifts the smaller valve disc, allowing it to be opened with relatively less force, which in turn creates equilibrium in pressure before and behind the valve. Once the smaller valve disc is open, the valve stem then lifts the larger valve disc, thus enabling the valve to be opened with minimal effort. As for closing, the medium pressure acting on the valve disc helps to facilitate the closure process. A stop valve is a one-way valve, as it always has a flow direction indicator, usually shown on the valve body in the form of an arrow. Therefore, when installing and using it, be sure to pay attention to the flow direction of the valve. In terms of body shape, it’s easy to tell the difference in height for those with an S-shaped figure, while it’s indeed difficult to discern such differences in those with an olive-shaped figure. So there’s no need to look at the height; just look at the direction of the arrow.
Inlet at the top and outlet at the bottom under low pressure; inlet at the top and outlet at the bottom under high pressure
Looking in the direction of the arrow, this means low in and high out (usually used for pressures below 40 kPa); inversely, it means high in and low out. (Generally used for pressures above 40 kPa at low pressure)
To add, low entry and high exit means what you described: low entry and high exit. . :)
Flow direction arrows are marked on the valve body. Assemble according to the arrows, and it definitely won’t go wrong.