spring 24 because the lip seal 23 urged open by the first piston 20 places the compression chamber 22 in fluid communication with the exterior when the first cylinder and piston system 19 is not compressed the inventive concept contained in the preferred example described above and relating to a steam cleaning machine is easily applicable to a different cleaning machine such as for example a sprayer nebulizer or vacuum cleaner where instead of the electrically operated valve the machine comprises other electrical components such as pumps fans compressors and the like the actuator means which are sensitive to variations in pressure could comprise instead of a cylinder and piston system a pressure detecting membrane or diaphragm these means could be contained together with the switches inside the casing of the machine instead of in the complementary plug in part likewise the pressure generating means could be a bellows design rather than a cylinder and piston system in addition to having the abovementioned advantage the cleaning machine according to the invention is easy to use and the possibility of separating the plug in means by means of the catch 11 makes positioning and storing the machine simple moreover when the complementary part 6b is detached from the machine casing the discharge of steam is cut off immediately which also occurs when the trigger lever is released even accidentally the presence of.