Pressure Washer, water properties exiting nozzle

In summary, the conversation discusses the consequences of introducing high heat on water in a hot water pressure washer. The scenario involves a pressure washer with a high pressure hose and trigger gun, fitted with a zero degree nozzle that allows all 6 gallons per minute of water to pass through. The question is asked about the properties of the fluid after leaving the nozzle if the water in the boiler is heated to 300F. The conversation also mentions the use of a surface cleaner and the potential for increased pressure due to heat trapped in the dome shell.
  • #1
Hi all. I hope to have a better understanding of the consequence of introducing high heat on water in a hot water pressure washer.

I know that hot water cleans better than cold or warm, and steam even cleans better. But am I harnessing the additional heat energy applied to the water in the scenario below?

Scenario: I have a a hot pressure washer capable of 6 gallons per minute at 4300 psi, the boiler is controlled by a thermostat (ambient to 325F) and is fitted with a burner capable of 700,000 BTU's. A high pressure hose and trigger gun is fitted to the boiler exit. The trigger gun has a port to install a quick connect nozzle. The nozzle installed is a zero degree nozzle(non-expanding), sized 0006.0 (at 4000 psi upstream pressure, this nozzle size would allow all 6 gallons per minute to pass through the nozzle).

Ok, here is the question: If I heated the water in the boiler to 300F what would be the properties of the fluid immediately after leaving the nozzle?

The pressure outside the nozzle would be atmospheric, correct?,

What phase or percentage of various phases would it have, and what about the fluid temperature?

Pressure wash operators use a tool called a surface cleaner, which passes the fluid through a high speed swivel, the fluid is then split into two or more equal portions via arms. The nozzles are angled at 15 degrees from the vertical to harness the reaction forces of the fluid stream and produce a rotating motion. The rotating arms are housed in a dome shell, which traps some of the heat and may allow for a small increased pressure over atmospheric, due to the low clearance between the dome and the surface being cleaned.

Thank You


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  • #2
Can someone explain what is happening just outside the spray nozzle under the conditions described?


What is a pressure washer?

A pressure washer is a tool that uses a high-pressure stream of water to clean surfaces. It is often used for outdoor cleaning tasks, such as removing dirt, grime, and stains from driveways, decks, and siding.

How does a pressure washer work?

A pressure washer has a motor or engine that powers a pump, which creates a high-pressure stream of water. This water is then forced through a nozzle at the end of a wand or gun, allowing for precise control and targeted cleaning.

What are the water properties exiting the nozzle?

The water exiting the nozzle of a pressure washer has several important properties. It is highly pressurized, often reaching up to 3,000 pounds per square inch (psi). It is also typically heated, which helps to break down dirt and grime more effectively. Lastly, the water stream is highly concentrated, allowing it to clean with a high level of precision.

What types of surfaces can be cleaned with a pressure washer?

A pressure washer can be used to clean a variety of surfaces, including concrete, wood, brick, and metal. It is important to carefully select the appropriate pressure and nozzle for each surface to avoid damaging it.

What are the safety precautions when using a pressure washer?

When using a pressure washer, it is important to wear protective gear, including goggles and closed-toe shoes, to prevent injury from the high-pressure water. It is also important to follow the manufacturer's instructions and never aim the nozzle at yourself or others. Additionally, be cautious when using a pressure washer on delicate surfaces or near electrical outlets.

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