Большая площадь проходного сечения клапана.

Valve orifice:
- общ. проходное сечение клапана;
- тех. отверстие клапана.
https://www.multitran.com/m.exe?l1=1&l2=2&s=valve orifice

***

"Use as Control Valve: Sizing of Valve Orifice

For correct and accurate control functioning, solenoid control valves must be configured and selected according to their special purpose. The most important parameters for selecting a solenoid control valve are, on one hand, the kV value (given in cubic meters per hour) and, on the other hand, the application’s pressure range. The lower the valve’s orifice or the stronger the coil, the higher the pressure the valve can shut-off. The highest kV value needed is calculated on the basis of the following parameters: Valve inlet pressure, valve outlet pressure, the fluid’s density, maximum flow rate
required, and the fluid’s temperature.
...
The correct configuration (determining the valve’s orifice) is extremely important for the solenoid control valve’s correct functioning. With a high orifice setting the valve can already reach full flow rate at a very small opening (stroke). The remaining stroke then is useless, which, more to the point, impairs resolution and the general control quality of the valve. With an orifice size that is too small on the other hand, the valve won’t reach full flow rate. In the interests of the system’s acceptable flow characteristics, the valve authority should not be below 0.3. That means that 30 % of the system’s pressure should be available to drop over the control valve.
...
...
For optimal sizing of the valve orifice there are some issues to be cleared up.
...
...
Within one type is generally valid: The bigger the valve orifice, the lower the maximum possible operating pressure at which the valve closes tight
...
This brochure contains both, electromagnetic and electromotive proportional valves. Solenoid proportional valves mainly cover the orifice range below 12 mm (direct-acting valves). The motor-driven valves distinguish between the orifice range 2-6 mm (seat valve) and 8-25 mm (disc valve)".

https://www.ventar.ru/sites/default/files/Burkert_CATALOG_Pr...

***

Расчет проходного сечения клапана - http://www.lda74.ru/catalogue?category=373

Расчет проходного сечения предохранительного клапана - http://www.aircoolsib.com/index.php?option=com_content&task=...
"F - площадь проходного сечения клапана, равная наименьшей площади сечения в проточной части, мм2".

***

Пример.

"Конструкция клапана предусматривает большое проходное сечение, что обеспечивает низкую потерю давления, открытие и закрытие клапана происходит менее, чем за 1 секунду".
https://www.madas.ru/catalog/klapany/mn28-dlya-dizelnogo-top...