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Pressure Washer Basics

How Does a Power Wash Machine Work?

Most people would skip over the pressure washer entirely to save a few bucks and just wash their sidewalks or siding by putting their thumb over the end of a garden hose. While this does create a much higher pressure stream than your garden hose alone, it doesn’t come anywhere near the pressure or cleaning power created by a pressure washer machine. If you want your surfaces to be satisfactorily cleaned and not just rinsed off, a pressure washer is the best way to go.

Pressure washers clean quickly and thoroughly. They get the job done in a small percent of the time it would take to complete the job without the help of a power washer. Read the text below to understand what a pressure washer adds to the cleaning experience that water from a regular garden hose lacks.

Pressure Washer Parts & Functions

Pressure washers are composed of six main parts: inlet, motor, pump, pressure hose, gun, and nozzle. Each of these parts plays an integral role in how a pressure washer functions.

Water enters the pressure washer through the inlet hose, then flows through the pump, which is activated by the motor. The pump is a lot like a heart, in that it pressurizes the liquid contents like the blood in our bodies. Remember Pascal’s Law which says a confined fluid cannot be compressed.

Like a heart, if the inbound fluid is not free of large particles, the pump will be blocked or clogged, and not function properly. Because of this, the inlet hose for a pressure washer should have a substantial amount of inlet filtration.

From the pump, the pressurized water is then forced through an outlet valve and into the pressure hose.

The pressure hose must be made of sturdy enough material to be able to handle the pressure built up in the pump. Depending upon the type of power washer, water pump outflow pressure can exceed 4000 PSI. For this reason, hoses are manufactured to withstand four times their pressure rating before bursting (4:1 burst pressure ratio).

Upon exit, the pressurized water rushes through the hose, toward the trigger gun.

Pressure Wash Nozzle Function

What keeps the pressurized water from spraying out of the gun nozzle uncontrollably? Trigger guns are designed with a ball bearing perfectly fit to the outflow valve (where the lance attaches). As water pressure builds, it increases the seal pressure between the ball bearing and the valve, ensuring leak-free operation.

When the gun’s trigger is squeezed, a pin pushes the ball aside, and the water shoots through the valve, through the lance, and out through the nozzle. Squeezing the trigger also activates the motor, pressurizing more water and ensuring an even, steady stream.

When the trigger is released a spring pushes the ball bearing back into position.

The spray head nozzle opening is smaller than the lance tube leading up to it, which means the built-up energy has to be converted to a new form—speed. The same amount of water exiting through a smaller hole increases the velocity and gives the water enough force to clean the appropriate surface.

Take Care with High-PSI Pressure Washers

Many lances include an adjustment dial or lever which regulates the stream, letting the operator focus the spray on a single, small area, or widening the jet’s reach to cover a larger area.

Naturally, higher velocity equals greater force available for dislodging dirt particles. Greater force means less water is used during the cleaning process, helping you clean faster. This in turn saves water, chemical costs, and time, getting you to the next job faster.

On the other side of the equation, high pressure water jets can cause permanent damage to the surface you are cleaning if the surface is painted, soft, or sensitive to force.

It is always recommended you use the lowest pressure possible to effectively get the job done. To ensure you don’t cause any lasting damage, test your water jet on an inconspicuous area beforehand.

Pressure Washer Supplies for Professionals and Home Maintenance

Pressure washing alone will not clean everything you need to clean. Oils and fats or other protein-based stains require some sort of binding agent to allow the water to wash it away. That’s where detergents come in. Detergents are emulsifiers and surfactants. They help bind water to oils and fats to help lift them from the surface you’re cleaning and wash them away. Detergents also don’t leave a film over the surface the way soaps do.

If you’re going to be cleaning a business, fleet, or your own home, pressure washers are a great option. They get the same amount of work done in a fraction of the time it would take you to do the job without a pressure washer.

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