Compare with original Y5-47, the noisy reduced significantly after the series of improvement, in order to satisfied with the requirements of bolier sets, we add other 8 new series, such as 4D(for bolier 0.7-1ton ),5D(for bolier 2ton),6D(for bolier 4ton),7C(for boiler 4ton 6ton),10D( for bolier 6ton ),11D( for bolier 10ton ),12D( for bolier..