Valves for supercritical parameters


15.4.2011 | In a new applications for industry sector we meet very often the requirement of supercritical range of working parameters for valves. Within our product range we are dealing with all the critical issues associated with such operations.

New designs – valves for supercritical parameters. For newly designed applications there is often a need to use valve for rated pressures above 400 bar. One of these applications are shutoff valves used in the Research Centre of Plant materials supercritical extraction using CO2.

In mentioned project, all parts of used valves were made from steel 316L, counterflanges from material X2CrNiMoN22-5-3 1.4462 (DUPLEX). Due to possibility of working pressures about 530 bar, rated pressure of valves was designed PN630 according to the norm BN-91 1771-20/40.

Seal between the valve body and counterflanges was designed with seal BX 150 corresponding to API 6A class 15000.

Valves have guaranteed tightness class V (seat/plug) at the maximum pressure drop of 530 bar, inlet of media is connected over the plug (FTC).

The pressure difference above and below the plug makes an additional downforce and helps to tighten the system. To reduce the required operating force of the actuator, there was used the construction of pressure balanced internal plug - pilot. Design of the pilot requires 7-times lower operating force than in case of main plug. After the pilot opens, pressure above and below the plug will be equal and next opening of valve (for achieving full flow) will not require any increased control force.

To avoid the damage of internal parts by high media velocity, in this case liquid carbon dioxide, plugs, seats and guide bushings are made using the full stellite protection with the hardness 45 HRC.

Valves are equipped with pneumatic actuators, solenoid valves for control and limit switches for indication the open/closed position.
If you found this aplication intteresting and you have any additional questions, please contact:
Zbigniew Witos, e-mail: 

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