Industrial washing machines: how the tunnel works

The tunnel washing machine works on one principle: the part moves forward, the stages come to it. Parts sit on a stainless steel conveyor belt and pass through four successive zones.

The four stages

1. Degreasing. An aqueous detergent solution, usually heated to 50–80 °C, is sprayed through nozzle manifolds from every direction. Temperature matters: oil releases far more slowly when cold.

2. Rinsing. Clean water, also at controlled temperature. It removes detergent traces and residue from the wash water. Without this stage, parts come out spotted — usually whitish — from limescale and other dissolved salts.

3. Blow-off. High pressure blowers and air knives. They clear standing liquid from holes, channels and hard-to-reach areas. This stage decides whether the part comes out dry or only apparently dry.

4. Final drying. Fan and electric heating elements. The part leaves fully dry, ready for the next operation.

What sits underneath

Each tank has its own heating system, its own recirculation pump and its own filter. The filter can be a removable box type or a bag type.

Filtration is not a detail. It retains impurities and extends the life of the washing solution. A solution changed less often means lower cost per part and less waste to treat.

Construction

Tanks and structures in contact with the solution are usually made of stainless steel. The reason is simple: the solution is watery, hot and contains detergent. Anything else rusts.

How it is selected

The machine type is chosen on two things: part type and production volume.

A small part in high volume calls for a continuous tunnel. A large part, one-off or in small batches, calls for a different configuration.

We supply systems for automotive, aerospace, tube production and defence. Every configuration starts from your part.

Related reading

• What industrial parts washing is and when you need it
• Industrial Washing
• Products