A Steam Pressure Washer Needs Steam Cleaning Nozzle
Although some hot water pressure washers have a steam stage, the term "steam pressure washer" isn't quite accurate.
Although the same cleaning machine may be capable of producing either hot high-pressure water or steam, there's a big difference in the way the two procedures work.
In a pressure washer operation, the pump simply pushes water out of a restrictive nozzle. The narrow passage through the nozzle increases the water's velocity and ultimately, cleaning power. In pressure washing, the pressure or restrictive nozzle is the last part of the machine the water flow passes through.
In a steam pressure washer, a very different process occurs. The steam cleaner doesn't so much use steam to clean as it uses steam expansion to propel water at near its boiling point at a high velocity - and the closer the steam cleaner's nozzle is to the surface to be cleaned, the higher the temperature and velocity of the water, the more effective the cleaning action. For most cleaning procedures the nozzle should be within 8 inches of the soiled surface for the best cleaning efficiency.
This steam vapor, with a properly designed steam-cleaning nozzle, also propels the remaining water droplets. Unlike a pressure washer nozzle, where the restrictive orifice is the last thing the water passes through before reaching the atmosphere, the steam cleaning nozzle has an expansion nozzle placed past the pressure orifice. This directs the water vapor energy rather than allowing it to dissipate in all directions.
Applications for steam pressure washing:
Heat is steam cleaning's biggest advantage as a cleaning method. The steam cleaning process delivers water at a temperature very near 212 degrees. This superheated water increases chemical effectiveness, including the ability of detergents to dissolve greasy soils.
Applications where heat is essential lend themselves more readily to steam cleaning, including:
- Oil and grease removal (from cement, siding, etc.)
- Preparing surfaces for painting especially when greasy or oily stains are involved.
- Cleaning buildings for restoration purposes. Steam cleaning is less forcefulthan high pressure cleaning, though flushing a surface with large volumes of water under low pressure my be even less intrusive than steam.
Major manufacturers of industrial steam pressure washers include Karcher and Daimer, pioneers in the pressure and steam cleaning industry. Northern Tool/NorthStar carries an electric model geared for light-duty, residential use, the 2000 PSI NorthStar Electric Hot Water and Steam Pressure Washer.
When it comes to discussing the advantages of cleaning with the close contact of steam or a penetrating blast of hot water, things are heating up!