English to Russian Tech/Engineering Engineering: Industrial pressure relief valves

The valve inlet (or approach channel) design can be either a full-nozzle or a semi-nozzle type. A full-nozzle design has the entire ‘wetted’ inlet tract formed from one piece. The approach channel is the only part of the safety valve that is exposed to the process fluid during normal operation, other than the disc, unless the valve is discharging.

Full-nozzles are usually incorporated in safety valves designed for process and high pressure applications, especially when the fluid is corrosive.

Conversely, the semi-nozzle design consists of a seating ring fitted into the body, the top of which forms the seat of the valve. The advantage of this arrangement is that the seat can easily be replaced, without replacing the whole inlet.

Поперечные разрезы каждого из этих двух типов можно посмотреть здесь: http://www.spiraxsarco.com/learn/default.asp?redirect=html/9...

Кстати, это прекрасный справочник по предохранительным клапанам (к сожалению, только на английском).