High-pressure water jet washing is generally done via an open air washing method. However, depending on the purpose of the washing, it may also be done using an submerged washing method.

Submerged washing is essential for cleaning complex parts. The synergistic effect of high-pressure jets and cavitation completely removes residual chips from hard-to-reach places within a part.

What are the features of the submerged high-pressure washing machine?

This high-pressure (1000 PSI) submerged CNC machine has the ability to carry out chip removal through submerged spaying using a high-pressure and small-flow rate jet. Compared with low-pressure and large-flow rate submerged washing types, the submerged high-pressure washing machine is superior in terms of its ability to carry out chip removal tasks. In addition to having a control that enables positioning precision of 0.08 mm, delivering highly accurate and efficient washing.

Why is washing done under water?

When a water jet is sprayed under water, it meets resistance from surrounding water, and this greatly reduces the power of the jet. However, submerged spraying has the result of creating cavitation between the jet and its surrounding water. Submerged washing is done in order to use the washing power created by the cavitation.

Cavitation is a phenomenon in which the pressure in a liquid drops below the saturation vapor pressure and begins to boil, resulting in the creation of micro-bubbles.

In submerged spraying, a vortex occurs between the jet and the surrounding water, and cavitation is created when the eye of the vortex experiences a drop in pressure in a similar manner to that of a typhoon. The micro-bubbles created by cavitation flow downwards and burst instantly when the surrounding pressure rises.

When this happens, an impact pressure of up to several GPa produces an intense noise, and this causes damage to the surface of the object located in the downstream of the jet. Submerged washing creates synergy between the washing power of cavitation and the spraying power of the jet.

Characteristic of the nozzle used for submerged spraying.
Before washing. Material: Aluminum.
After washing. Pressure: 725 PSI.

How is washing done and is this applicable to?

In general, it’s carried out by the following process:

Workpiece loading → Rapid water supply → Submerged washing → Rapid water discharge → Rinsing → Draining → Workpiece unloading

The type of work in this process is applicable to parts such as cylinder head, cylinder block, valve parts, precision casting parts, engine parts for vehicles.

Brick erosion test

Submerged spraying that uses this type of cavitation demonstrates a superior washing power over open air spraying.

Look at the images below for the spray comparison:

Open air spraying.
Submerged spraying. A penetration hole was created as well as cracking.

See technology in action.