Abstract: The steam trap constitutes a miniaturized single block set, which regulator integral element are assembled inside a single part body with a ringing anchorage slot for the regulator filter and keyways for placement of the lugs of a washer acting as a wedge key, under which is located a guiding nut of the respective plug carrying spindle that forms part of the regulator. This washer has a polygonal passage inside which is located a V shaped portion of the guiding nut, preventing its turn whenever the plug carrying spindle is turned to effect the regulation, spindle which does furthermore pass through a bimetallic package and through another lower nut, which last two elements complete the regulator. The steam trap thus obtained does not have a cover, sealing joint and cover-main body joining elements, allowing the ready inspection and handling of the internal elements that make up the regulator.