A power washer is a mechanical sprayer that uses high-pressure
water to clean and remove mold, grime, dust, mud, and dirt from surfaces and objects such as buildings, vehicles, and concrete
road surfaces.
Equipment can be rented or bought that produces pressures
from 50 bars (750psi) up to 1200 bars (30,000psi) or more. A pressure washer differs from a parts washer in that a parts washer
typically uses high-volume, low-pressure (20-150 psi) cleaning solutions in an enclosed cabinet to clean dirty parts.
The most basic pressure washer consists of:
- A
motor which directly drives a water pump
- High-pressure hose
- Trigger gun-style switch
- Just as a garden
hose nozzle is used to increase the outflowing dynamic pressure of the liquid, a pressure washer adds its own power to force
high-dynamic pressure.
Note that the pump does not draw more water
from the pipe to which the washer is connected than that source can provide; therefore, the water supply must be adequate
for a given machine to be connected to it: its flow must be equal or superior to that of the washer, so that the pump is never
starved (which can damage it).
Several different types of nozzles are available,
each useful for a particular application. Some nozzles cause the water jet to be ejected in a triangular plane, while others
emit a pencil-thin jet of water, which spirals around rapidly. Most nozzles attach directly to the trigger gun.
Some pressure washers, in combination with a particular nozzle, allow detergent to be introduced
into the water stream, assisting in the cleaning process.
Two types of
chemical injectors are available: a low-pressure injector that introduces the chemical after the water leaves the pump (a
downstream injector) and a high-pressure injector that introduces the chemical before water enters the pump (an upstream injector).
The type of injector used is related to the type of detergent used as there
are many chemicals that will damage a pump if an upstream injector is used.
