High pressure cleaner, one of the most common cleaning machines of today, possesses flexible methods of cleaning and has the most varied applications. Flexible, as it can clean components, cars, machines, equipment and buildings from the inside or outside, vertically or horizontally.
The water applied at high velocity to a dirty surface generates a high impact pressure which loosens the adhesion between the dirt particles and the surface. Apart from the mechanical dirt removing action, there are three more factors that play important roles: temperature, cleaning agent and reaction time.
Buying HP cleaner
Anyone wanting to buy a high-pressure washer has a vast number of units to choose from. Leading manufacturers offer up to 60 models in three different performance classes. The following general rule applies: Heavy-duty units are suitable for cleaning large objects and construction machinery as well as for agricultural applications. Those who have to clean machinery, vehicles or factory premises in a fixed location on a daily basis, usually select a versatile medium-duty HP cleaner.
If it is necessary to work at different locations or the machine is to be used only occasionally for light cleaning work, the best choice would be a comparatively low-priced entry-level model. Mobile high-pressure cleaners should preferably be lightweight and compact enough to fit into an estate car. Machines are offered with 230 V/50 Hz, 3-Phase 400 V/50 Hz and with combustion engines either petrol or diesel. Upright units with large wheels and an adjustable push handle can easily be moved over all types of terrain, including uneven ground and steps, like a cart.
The performance of a HP cleaner depends primarily on the pressure and water delivery rate of the pump. When comparing models, many users focus on the maximum achievable pressure, and thus the dirt-removing effect. In many cases, however, the water volume and its flushing action hold a much greater influence on the cleaning result. This factor is particularly important in those cases where large quantities of dirt have to be shifted from machinery or floors, e.g. in the construction industry and in agriculture.
Entry-level models in the cold-water high-pressure cleaner line operate at a defined pressure. With most units, however, the pressure can be adjusted within a predefined range. The adjustment can be made either on the unit or – more conveniently – directly on the trigger gun. The latter method allows the operator to react flexibly to changing surfaces which are not all of the same consistency.
In many cases, dirt can be reliably removed with a cold-water high-pressure cleaner. If necessary, the cleaning process may be speeded up or improved by using detergents. The detergent quantity can be set to the required minimum and added via a metering valve far more accurately than by hand. Contrary to manual dosing, the risk of over-dosing with a metering valve is minimized. This avoids unnecessary consumption of detergent and reduces costs. Units with built-in detergent tank have a convenient level indicator. Most cold-water units can be used with feed water at a temperature of 60°C, which enhances the cleaning effect. On models with a water-cooled motor, the water is preheated and this also helps save energy.
Hot-water units are effective
On hot water HP cleaners (with a diesel or electric burner), the dirt removing properties of water, pressure and, if necessary, detergent are further improved by the ability to heat water. Such hot-water units have a number of advantages:
• Oil, grease and other types of soiling are removed much more easily and quickly. In some cases, there is no need for detergent at all
• In the steam mode (boiler temperatures from 80 to 155°C) sensitive surfaces can be cleaned at a reduced pressure. Pathogenic micro-organisms are effectively reduced before subsequent disinfection is carried out
• As the steam mode works with reduced water quantity, it is also suitable for sandstone, mineral plaster and other porous natural materials which are hygroscopic
• The surfaces cleaned heat up and dry faster
Compared with cold-water units, cleaning times can be reduced up to 40% in practice by using water heated to 80°C, and the results are better. It is obvious that, with time savings of this kind, a hot-water unit quickly pays for itself.