Abstract: A flow rate converter has a body with a cyclindric tube and an inlet and an outlet diffuser. The tube and body have inner annular conduits connecting with pipe connections disposed in the body. The body is also provided with a heating element. A replaceable cylindric body is inserted in the cylindric tube and is provided with first axial channels providing for a laminar flow and second axial channels of which at least one has a cross-sectional area at least two times larger than the cross-sectional area of the first channels. In both ends of the second channels are formed chambers while a replaceable cover with openings is fastened to the outlet diffuser.