Pressure washers are machines capable of spraying high-pressure water to clean a wide variety of items. Not only are they 10 to 50 times more powerful than a garden hose, but they also have the advantage of using up to 80% less water.
The first models of pressure washers appeared about 60-70 years ago and since then they have been applied in various tasks, such as removing loose paint, mold, dust, mud and dirt from objects such as vehicles of all kinds and from concrete surfaces, masonry and floor, ceiling and wall coverings for homes, buildings and other constructions.
Pressure washers work in a very simple way: pressurized water emerges at high speed through a hose at the end of which a fine nozzle is connected, producing a jet of great force to loosen dirt. Most models also allow you to add detergent and other cleaning products (even sand), which increases the cleaning power of the jet.
The central element of all pressure washer is a motor, which, in turn, triggers a bomb which pressurizes the water so that the water emerging from the nozzle is at a much higher pressure than when it entered the pressure washer. Depending on the type of power supply of this motor, we can group these machines into two large categories.
electric pressure washers: the motor runs on electricity supplied by a nearby outlet and therefore these machines They have a power cable that restricts their movement over large surfaces. They are light models, indicated for cleaning jobs that do not require too much power. They are typically quieter, lighter, and easier to start than gasoline models, making them ideal for indoor jobs.
Fuel pressure washers: They incorporate an internal combustion engine and the current offer varies from medium performance models to ultra-high performance models. They offer the benefit of greater power and greater mobility, since they do not require an outlet. They use a manual starting system or, on some high-powered models, an electric starter. Still other models can generate hot water, which can be great for loosening and removing grease and oil. Due to the hazardous nature of engine exhaust fumes, these machines they are not suitable for indoors or places that lack good ventilation.
Most of the pressure washers Current ones connect to an existing water supply, such as a garden hose, but some manufacturers have a built-in water tank attached to the machine. There is usually an on/off switch that controls the water flow and many models even allow you to adjust the water pressure.
Apart from the motor and the high pressure pump, all the pressure washers they have a high pressure hose and one spear, at the end of which is a trigger switch pistol type, to which various types of nozzles.
The following figure shows a schematic of a gasoline pressure washer with its parts.
one. Spray Nozzles – Many models come with options for detergent and 0º, 15º and 40º spray, offering different high pressure cleaning applications.
two. High Pressure Hose – One end of this hose connects to the water pump and the other end to the spray gun.
3. Pressure Control Knob – Allows you to vary the spray pressure.
Four. Water inlet: it is the connection for the water supply through a garden hose.
5. High Pressure Outlet – This is the connection for the high pressure hose supplied with the machine.
6. Pump: is the element that produces high pressures. There are basically two types of pumps, axial cam and triplex. Triplex pumps are typically found on pressure washers designed for commercial use due to their longer life and efficiency.
7. Oil level indicator: it must be checked periodically, since the useful life of the engine depends on this.
8. Detergent suction tube/filter: used to safely suck detergent into the low pressure circuit.
9. Choke Lever – Prepares cold engine for starting.
10. Fuel Valve: Used to turn the fuel supply to the engine on or off.
eleven. Engine and manual starter: the starter is used to start the engine manually.
12. Throttle Lever – Places the engine in manual start mode.
13. Engine switch: it is of the “On/Off” type and allows manual starting and stopping of the engine, respectively.
14. Air Filter – Protects the engine by filtering dust and debris from the air intake.
fifteen. Fuel tank: Care should be taken to fill it with regular unleaded fuel and leave enough space for fuel expansion.
16. Lance and spray gun: controls the application of water on the surface to be cleaned with the trigger and allows switching between several different spray nozzles.
In this other figure we see a electric pressure washer with its parts.
one. ON/OFF switch
Four. Ground Fault Circuit Breaker
5. Power cord
6. detergent hose
7. Adjustable flush knob
8. water inlet
9. water outlet
10. high pressure hose
eleven. Lance/Gun Mount
12. quick connect nozzles
Most nozzles connect directly to the trigger switch. There are different types of nozzle for different applications. Some nozzles create a jet of water that forms a triangular plane (fan type), others emit a fine jet of water that rotates rapidly in a spiral (cone type).
Parameters of pressure washers
The power of a motor pressure washer Gasoline is measured in HP (horsepower), while the power of a gasoline engine pressure washer electrical power is measured electrical power is measured in W (Watts) or kW (Kilo Watts). It is clear that the higher these parameters are, the more powerful the machine will be.
The flow of pressurized water emerging from a pressure washer expressed in gallons (GPM) or liters per minute (LPM), it is often designed into the pump and is not variable. The Pressure, expressed in pounds per square inch (PSI), megapascals (MPa), or bar, is designed into the pump, but can be varied by adjusting the discharge valve. Multiplying the flow rate by the pressure gives an indication of the strength of the pressure washer. The market has machines producing pressures of 750 to 3000 PSI (5 to 20 MPa) or more.
According to the application that we want to give to a pressure washer, the following table can guide us about the flow that we should choose for our machine.
Uses and precautions
The pressure washers are tools care and must be handled with due attention to safety instructions. The water pressure near the nozzle is powerful enough to seriously injure the user. Not only is the water jet ejected from the nozzle at high speeds, but also the cleaning process can propel, also at high speeds, detached objects from the surface being cleaned. On the other hand, pressure washers they tend to break the concrete if the jet is directed at it, due to the high pressure of the water penetrating the cracks and voids in the surface.
Depending on the surface to be cleaned, each application has its own specific procedure. Here are some general rules to keep in mind:
- Always use the correct nozzle or spray setting. Using a nozzle or setting that concentrates too much power can damage some surfaces, especially wood.
- Use the chemicals recommended by the manufacturer, which generally has approved detergents and waxes for use in their machines. There is a wide variety of formulations for cleaning and degreasing homes and terraces, as well as for washing and waxing vehicles.
- When cleaning a home or building, work should be done from the ground rather than using a ladder, and provided accessories such as spray lances and brushes designed for this purpose should be used.
- Cleaning results vary depending on:
- Use of detergents
- Distance from the surface being cleaned
- water pressure
- Spray fan angle
- Safety is essential when using a machine like the pressure washer, which combines pressurized water, detergents, or other chemical products, and electricity or gasoline, so compliance with the manufacturer’s instructions and the use of personal protective equipment are part of the success to get the most out of this useful tool.
Explanatory video of the operation of a pressure washer