Pressure washer

Reminder on how a high-pressure cleaner works

A pressure washer is primarily characterized by its pump. It is therefore the single-phase (220 Volts) or three-phase (380 Volts) electric motor or thermal engine that will drive the pump, which provides a constant flow of water at a given pressure. The lance allows the water jet, possibly mixed with detergent, to be directed and the water to be projected through the nozzle.

Benefits of cleaning with a high pressure cleaner

Manual cleaning with mops, sponges, brushes is not economical, professional and even less hygienic and effective.
High-pressure cleaning allows you to obtain:
• saving time:
=> up to 75%
• better hygiene:
=> the loosened dirt is removed and not spread • water saving:
=> the flow rate of a water tap can exceed 2500 l/h, an NHP uses between 500 and 1200 l/h+
• energy savings:
=> cleaning is done more quickly
=> the NHP makes it easy to clean hard-to-reach places, without fatigue.

Nilfisk, the benchmark in professional high-pressure cleaners

Nilfisk is a renowned manufacturer of professional pressure washers. Their products are known for their reliability, efficiency, and durability. Nilfisk often manufactures for multiple brands and integrated well-known brands like Kew in the 2000s. If you're looking for a professional pressure washer for your business, Nilfisk offers a diverse range of models tailored to your specific needs. From single-phase cold water pressure washers to stationary pressure washers for car washes, including standalone gasoline-powered pressure washers, Nilfisk has the know-how.
By choosing a Nilfisk professional pressure washer, you can be sure of exceptional cleaning results while benefiting from the reliability and durability of a trusted brand.
Personal protective equipment
Working with a high-pressure cleaner requires the use of personal protective equipment such as disposable coveralls and, more specifically, waterproof coveralls , protective gloves, safety glasses and suitable safety shoes .
Wearing safety shoes or boots is also strongly recommended.

Performance displayed in pressure and flow rate

Water Pressure / Flow: Cleaning Impact
• Impact is the force with which the water hits the surface to be cleaned. It gives an indication of the cleaning effectiveness.
• Water flow influences the impact value more than pressure.
• Calculation formula: IMPACT=(0.024xl/min)x bar / 0.981
Example: A machine of 180 bars/1000 l/ha an Impact coefficient of 5.4
=> If we increase the pressure by 10% , we obtain 198 bars with an impact of 5.7, i.e. + 5.5% efficiency
=> On the other hand, if we increase the flow rate by 10% , we obtain 1100 l/h with an impact of 6.0 or + 11.1% efficiency
It is therefore clear that manufacturers often emphasize pressure from a marketing point of view, but it is much less important than water flow in terms of performance.

Water Pressure / Flow: Wash Impact vs. Wash Distance
• If we increase the distance between the surface to be cleaned and the HP nozzle, we reduce the impact force but we increase the cleaned surface .
- Recommended cleaning distances:
-> 5 to 10 cm for stripping very resistant surfaces (stone, raw metal, etc.)
-> 10 to 15 cm for washing resistant surfaces (painted metal, concrete, tar, etc.)
-> 10 to 20 cm for washing fragile surfaces (plaster, wood, etc.)
-> +20 cm for rinsing

Water Pressure / Flow: Wash Impact vs. Wash Distance - Performance
-> Performance is the most important point to optimize cleaning costs and limit machine wear:
-> The higher the water flow rate, the higher the efficiency.
- Reduction of working hours
- Reduced machine wear
-> If we increase the distance between the surface to be cleaned and the HP nozzle , we reduce the impact force but we increase the cleaned surface.
Explanation :
-> A high-pressure cleaner with a 500l/h water flow rate has the same cleaning impact at 6 cm from the
surface than 1200 l/h at 22 cm from the surface.
-> Thanks to the standard nozzle angle of approximately 20°, the cleaning width increases from 2.7 cm to 10 cm, i.e. 300% more performance !

Water Pressure / Flow: The Right Nozzle for the Right Application
-> It is not possible to increase the working pressure of an NHP
-> On the other hand, it is perfectly possible to reduce the pressure by increasing the nozzle size
-> At the same time, increasing the spray angle of the nozzle will increase the efficiency
? Adapting pressure to customer needs
? Reduced working time with a wide jet nozzle
? Enhanced security for fragile surfaces

How to choose your professional high-pressure cleaner?

With all the above explanations in mind, you can now better understand the figures given for pressure washers. As we've seen, it's a common misconception among pressure washer users that the pressure in bars is the deciding factor. This is a shortcut, and of course, as you'll have now understood, many other parameters will give you the true performance and impact force of your pressure washer.
The parameter that is often forgotten is the water flow rate.
Indeed, it is the multiplication of the pressure and flow rate of the pressure washer that will give a real value of the performance through the impact force calculated above. Thus, high pressure linked to a low flow rate will have no effectiveness.
Cleaning with a pressure washer can save you up to 75% of your time.
Water saving: in fact, the flow rate of a water tap can reach up to 2500 l/h, a high-pressure cleaner provides between 500 and 1300 l/h.
The choice of a high-pressure cleaner is also made in relation to its power supply: single-phase 230 Volt high-pressure cleaner (Pay attention to the available amperage), 400 Volt three-phase equipment (specify with or without neutral), autonomous high-pressure cleaner (petrol or diesel engine).

Key parameters in summary

- Pressure. This indicates the force of the water jet coming out of the lance or pump, depending on the technical data sheet, and is expressed in bars. High pressure makes it easier to clean stubborn dirt. However, this criterion for selecting a professional pressure washer is not without a second parameter, which follows, which is the flow rate.
- The flow rate. This data is expressed in liters per hour , and indicates the volume of water projected . Pressure alone is nothing if the flow rate does not follow. When the flow rate is high, it will allow large surfaces to be cleaned more efficiently. The impact force is the result of its pressure and flow rate values as explained above.
- The installation present on the construction site . Many models operate with electrical energy, and can be single-phase or three-phase. It is therefore necessary to take into account the installation available on the construction site, and check which connections are possible. Some locations are devoid of any electricity. It will then be necessary to opt for a professional thermal high-pressure cleaner, running on gasoline and therefore autonomous in terms of energy.
- Budget. This is inevitably a key factor. Depending on the budget allocated to purchasing a pressure washer, there are a variety of models available. Don't forget about Voussert's promotions, which regularly offer bargain prices for professional electric or thermal pressure washers.

The different types of professional pressure washers

Professional pressure washers come in two distinct types. The first is electric, while the second, a gas-powered model, requires gasoline. What are the advantages and disadvantages of each model?

Electric pressure washers

When it comes to professional pressure washers, the electric version, whether single-phase for standard models or three-phase for more powerful models, is the benchmark. Powerful and versatile, it is also more environmentally friendly than its thermal counterpart. However, the requirement to connect it to an electrical outlet somewhat diminishes its appeal. It is essential that the site has such an installation to use the electric pressure washer. In addition, you must pay attention to the amperage required, particularly when starting the device. Indeed, the most powerful single-phase pressure washer requires a socket with a minimum of 16 Ah . The same goes for three-phase, where the installation and amperage must be adapted to the cleaner. It is therefore imperative to check the suitability between the amperage of the socket and your device.

High pressure thermal cleaners

A professional pressure washer with a thermal engine is essentially distinguished by its internal combustion engine, using gasoline or diesel to operate. Their autonomy is greater than models powered by electricity, as these thermal devices do not require a power outlet to be operated. However, the noise and pollution they generate can deter the purchase of these models. The main criteria for purchasing a thermal model is above all autonomy and mobility while maintaining high cleaning capacities. This type of model is preferred in certain professions such as construction and agriculture where mobility and autonomy are predominant.

Maintenance and upkeep

The maintenance and upkeep of a professional pressure washer will vary depending on whether the model is thermal or electric. However, there are some common elements between the two.
So, in either case, pressure washer maintenance should be performed immediately after use. It is important to rinse the cleaner with clean water to remove any residue from the system. The detergent or cleaning product water tank should also be emptied, if the model has one. It is also recommended to clean dirt and cleaning product residue with a damp cloth. Furthermore, in the case of a thermal pressure washer, allow the engine to cool before storing it.
Maintaining a thermal model requires more attention. In this regard, it will be important to check:
- The need to change the fuel, according to the manufacturer's recommendations;
- The engine oil level, in order to top it up if necessary;
- The condition of the spark plug, with a view to replacing it if it is damaged.