Object completely dynamic valve working principle and classification

empty application is one of the most important in the combined cycle power plant application. These pneumatic valves must be at the beginning of the run to waste heat boiler main steam bypass steam turbine emissions into the atmosphere, to ensure that the temperature will not rise too fast. Do this because process pipeline in allow steam to the turbine bypass pneumatic valve before into the condenser, is hot. Working principle of the

in the application of high temperature and main steam ( High voltage/medium voltage/low voltage) By the bypass into the atmosphere, at the beginning of the waste heat boiler ignition, pressure and temperature rise to a particular point. Due to the pneumatic valve under full differential pressure control, pneumatic valves and downstream piping can produce high noise and vibration. Therefore, downstream usually
will install current-limiting devices such as diffuser or silencer. This design is to provide a back pressure pneumatic valve, in order to limit the pressure drop, and then produce the noise and vibration. It can also be used for before leaving the system was introduced into the atmosphere to reduce noise. Pneumatic valve noise control requirements are usually decibels. In some cases, the thermal insulation layer can be used to satisfy the requirement of noise. However, in many applications, the downstream pipe pneumatic valve without any heat preservation. The far field noise requirements depending on the location of the factory, but the general requirements for the fence line db. In addition to the noise and vibration is another problem closely shut off. Because of the pneumatic valve is typically used for vehicle in the process of start or factory, they must be kept closed during normal operation. If there is a obvious leakage of pneumatic valve, steam will loss. Most of the time, the loss of steam is enough to affect the steam turbine performance guarantee. High pressure (classification of

psig） And intermediate reheat (pressure/heat psig） The experience of the application temperature is close to the F. In the temperature, need to use the CA or F ( %Cr） The pneumatic valve body material. In addition, the temperature, the aerodynamic body of bolt materials need to be examined. As the temperature rises more than F, the steel bolt load will be greatly affected. Steel material of bolt will be faster than the CA elongated, lead to pneumatic on the body and bonnet joint leakage. Therefore, when fisher suggested F temperature adopts Inconel alloy material. As temperatures rise, tight shutoff become even more of a challenge. In the past in the light of the guiding type industrial balance problems of the stability of pneumatic valve core, and fisher C seal is designed, using pressure pneumatic auxiliary metal sealing with metal to metal seat internal parts. Provides a 'double' cut-off temperature can reach F Class V level of protection, and for high voltage/medium voltage/hot reheat object completely provides lasting shutoff valve. It should be pointed out that middle pressure to warm/hot object completely move valve application condition, depending on the pneumatic valves in the boiler pipe position, might be different. If the pneumatic valve placed behind the medium pressure superheater ( Medium pressure object completely dynamic valve) The highest temperature, pneumatic valve tolerance for F. If pneumatic valve arrangement (behind the reheater Another hot object completely dynamic valve) The highest temperature, pneumatic valve tolerance for F. Object completely moving valve pressure is very low ( psig） , but the temperature still can achieve F. Under this temperature, fisher use spring-loaded seal ring and the structure of polyether ether ketone crushing ring, to ensure that the sealing ring not extrusion deformation. In order to solve the problem of noise, the noise attenuation is recommended for the technology, rather than restrict pneumatic valve flow ability. System optimization is necessary to ensure that the best solution. Given this, pneumatic valves and muffler needs to be grouped together to calculate. This eliminates the restrictions on pneumatic valve flow capacity, or the possibility of higher than expected level of noise.
high pressure object completely dynamic valve: '- 'ANSI EH pneumatic valve body, the use of CA chromium molybdenum alloy steel material, with a Whisper or III WhisperFlo noise reduction internal parts, C type sealing structure of tight shutoff, combined with the downstream diffusion/muffler.
medium voltage to warm/hot object completely dynamic valve: '- 'EH of the ANSI or EU pneumatic valve body, using CA chromium molybdenum alloy steel material, Hot hot again) ； Or '- 'ED pneumatic valve, pneumatic valve body material (WC chrome molybdenum steel Medium voltage) With using Whisper III or WhisperFlo noise reduction internal parts, C type sealing structure of tight shutoff, combined with the downstream diffusion/muffler.
low pressure object completely dynamic valve: '- 'ANSI ET pneumatic valve body, the use of WCC carbon steel material, with a Whisper III or WhisperFlo noise reduction, high temperature structure of tight shutoff, combined with the downstream diffusion/muffler.