Whether it is a single-core valve or a dual-core valve, the fluid flows in from below and out from above.

It’s best not to generalize; it’s usually like this, but it can’t be generalized – there are also special cases. It is necessary to understand the principle of specific valves in detail. I have encountered a globe valve with flow from high to low, and its performance was excellent. Such devices must not be treated as a monolith; it is essential to understand them on an individual basis. To avoid making mistakes.

Most cases involve low entry points and high returns, but there are exceptions.

I glanced at the question bank in the dashboard occasionally; the answer was √, but I personally think there’s clearly something wrong with this question

Single-core and double-core represent different sealing types for valves, while the bottom-in-top-out configuration (commonly known as the flow-open type) is determined by the direction of the fluid flow. This configuration is generally used when the pressure of the fluid is too high; it is employed to prevent leakage from the upper valve chamber, with the pressure-bearing area being located at the bottom. This approach helps to reduce the sealing pressure on the upper valve chamber. In the top-in-bottom-out configuration (commonly known as the flow-close type), the upper valve chamber serves as the pressure-bearing area, and this design allows the valve to close tightly due to the direction of the fluid flow. When the pressure difference exceeds 15 MPa, a pre-actuation device must be added to the valve core; otherwise, a large amount of force would be required to open the valve. A metal self-sealing device should also be installed on the seal of the upper valve cover to ensure that there are no leaks; I would appreciate any feedback on this personal opinion.