For owners of paved driveways and yard areas, the pressure washer is often a beneficial invention. An effective cleaning effect can be achieved with relatively little physical effort. Nevertheless, compared to cleaning without mechanical assistance, there are some aspects that make manual labour an advantage.
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Do not underestimate the water pressure
The pressure with which a high-pressure cleaner works is often underestimated. The device exceeds many other everyday water pressures many times over. Anyone who has ever seen water escaping in a fountain during a water pipe burst has witnessed a water pressure of two to four bar. Normal high-pressure cleaners are often used in the pressure range between eighty and 160 bar.
The following examples show water pressure encountered in everyday life. The atmospheric air pressure (one bar) must be subtracted from all figures.
- One bar delivers water to a height of ten metres
- One bar corresponds to about one kilogram on one square centimetre
- Water comes from public pipes at two to four bar
- The water pressure increases by one bar for every ten metres of depth
- A car tyre needs about 3.3 bar
- Police water cannons “fire” at up to twenty bar
- 200 bar pressure in a cylinder/pipe (ø6 cm) exerts a weight force of 5.55 tonnes.
When cleaning the pavement, use the right amount of water and work carefully
The immense force can roughen and damage concrete and, if used inappropriately, even blast off corners and edges. Material removal begins at 600 bar impact pressure. Anything loose, such as earth and gravel fillings in joints, plant troughs and loosened paving stones, can easily be “catapulted” by impact pressures of eighty bar or more. This danger does not exist with brushing and scrubbing cleaning without a high-pressure cleaner.
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Advantages and disadvantages of cleaning with a high-pressure cleaner
- Less physical effort
- Time saving for large areas and heavy soiling
- Lower water consumption
- Less frequent cleaning intervals due to adjustable pressure force
- Motor noise leads to noise pollution in the evening, on holidays and at weekends
- Power requirement
- High-pressure cleaner can be defective
- Sensitive joint filling compounds (earth, gravel, chippings) rinse and spray out
- Risk of spraying dirty water on walls or partitions
- Purchase or rental costs