Inside the vale core of Bellows-type steam  trap's stainless steel pipe, there is filling with  a liquid which gasified temperature lower than the temperature of satureted liquid water . With the change of steam temperature control valve openning and closing.It has  the valve adjustment bolt,which  can adjust the using temperature according to the need. the general cooling of the adjustment range lower than the saturation temperature of 15 -40 . Back-pressure rate more than 70%, can be stopped from cold, and the size is small , can be installed anywhere,and  can drain non-condensing water successively. Finallt, it has long service life.