High pressure washer nozzle characteristics and design guidelines


The nozzle is a high-pressure cleaner in the implementation of the components. The principle is to use the nozzle hole changes in the high-pressure water gathered, converted into kinetic energy, and then sprayed out in the form of high-speed jets so that the material into the scouring, stripping, and breaking achieves the desired cleaning machine effect. The nozzle is also the last fluid channel, which plays the final acceleration and deceleration, control atomization, exit speed, and the role of the critical components of the spray range. Its performance will directly affect the cleaning effect. But how to play the cleaning effect to the best has been a problem for the practitioners. The following from the commonly used nozzle characteristics and design guidelines to explain two aspects.

What is high pressure cleaner nozzle?

The nozzle is one of the executive parts of the high-pressure cleaner. Using the nozzle hole cross-sectional area changes the high-pressure water flow gathered into kinetic energy and then sprayed with a high-speed jet, which will be cleaned on the surface of the adhesion of the brush, stripped or broken, to achieve the desired cleaning effect.

Common nozzle structures

The nozzle structure commonly used on high-pressure cleaners is cylindrical (linear), flat fan-shaped two.

2.1 Cylindrical nozzle

The cylindrical nozzle is the most commonly used continuous jet nozzle and is a solid flow nozzle derived from the cone convergence basis. Due to the solid flow nozzle jet sprayed by the local concentration of striking force and target distance, both the ability to gather and gather the jet, you can get the maximum remarkable power, the shape is also the most conducive to the manufacture of high-precision products.

2.2 Fan nozzle

The fan nozzle is directly from the shape of the nozzle to produce a flat and uniform jet. Its jet denseness is suitable, but the diffusion angle can also change significantly. The general fan nozzle angle can be changed in the cleaning machine between 10 ° -65 °. The angle is too large to lead to severe atomization and energy loss. Among the commonly used grade is 15 °, 25 °, 30 °, 40 °, and 65 °. The advantage is that the cleaning area is several times larger than the cylindrical nozzle, used in some cleaning area requirements and cleaning speed requirements for fast occasions. However, due to the diffusivity of the jet, compared to the cylindrical nozzle, jet energy, and pressure loss is significant.

The main factors for evaluating nozzles

3.1 Pressure and Flow Rate

The pressure and flow rate of the nozzle reflect the machine’s performance, and the orifice diameter of the nozzle is directly related to each other. The pressure and flow rate are mutually effective changes. The flow rate values at different pressures are not the same.

3.2 Spraying angle and coverage

Theoretical coverage is calculated based on the spray angle and distance from the nozzle (Figure 1); changing the value is based on the assumption that the spray angle remains constant throughout the spray distance. In the actual spraying, the effective spray angle varies by length. Factors affecting the injection angle are flow rate, pressure, and liquid viscosity. For a flat fan nozzle, due to the different grades of spraying (commonly used flat nozzle spraying angle is between 10 ° -65 °), its theoretical coverage at a certain distance from the nozzle is different, which is the main factor in determining the cleaning area. Cylindrical (linear) nozzle, due to its angle of 0, the impact cross-section is theoretically a point, theoretically no change in the spray coverage.

3.3 Impact force

Impact force is the impact force of the jet fluid on the target surface. A measure of nozzle impact performance indicators is the force per square centimeter. This value depends on the shape distribution of the jet fluid, the angle, and the distance to the target surface. Generally, the impact force decreases with increasing spray angle for a given spray shape distribution.

3.4 cleaning efficiency

Cleaning efficiency is an indicator to assess the performance of high-pressure cleaners. The industry does not have unified assessment methods and standards. For some foreign information, the assessment is one of the evaluations of high-pressure cleaning machine performance indicators. Nozzle cleaning efficiency depends first on the rated pressure and flows rate of the cleaner itself; under the same pressure conditions, the greater the flow rate of energy transfer, the higher the efficiency.

Nozzle material selection

Nozzle materials can be selected from metal or plastic. The available materials are copper, ordinary stainless steel, hardened stainless steel, stainless steel (need to do salt bath anti-rust treatment), and plastic materials such as POM, PA6, PA66, etc. There is also the use of ceramic. Material selection depends on the following aspects.

(a) pressure range.
(b) pressure drop requirements after the endurance life of the machine.
(c) cleaning effect requirements.
General pressure between 30-70 bar. You can choose copper, POM, and other materials. Pressure in the 70 bar or more usually determines copper and stainless steel materials.

To sum up, the nozzle as a high-pressure cleaner executive component, although the parts are simple, the final effect of the use of high-pressure cleaner has a significant impact. Understanding the characteristics of the nozzle, in the design process of continuous optimization, through a reasonable method of verification and evaluation can significantly improve the cleaning efficiency and enhance the efficiency of the use of high-pressure cleaners so that the performance of the equipment to maximize.


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