Vacuum filter / Negative-pressure filter

Function

The dirty liquid flows into the dirt chamber of the filter through an inlet distributor that avoids turbulence. The exhauster draws air and thus liquid through the fleece into the clean chamber of the filter, thus creating a negative pressure. This negative pressure increases the flow rate, allows the filter cake to build up higher and, as air is drawn through this filter cake, produces a dry stab-proof discharge. The higher-building filter cake provides a high-quality filter layer that improves the degree of purity.

The filter discharge pump directs the cleaned liquid into a clean tank. At a maximum level in the dirt chamber, a fleece pre-stroke is triggered. At the same time, the used fleece is conveyed into the dirt container and a fresh fleece is drawn in. The filtering process does not have to be interrupted for this operation; no buffer tank is necessary.

Due to the short fleece pre-strokes, only a very small part of the filter surface is renewed, so that the built-up filter cake remains largely intact as a “precoat” thus increasing the filter fineness.

A hose seal, resistant to all commercially available cooling lubricants, reliably isolates the dirt chamber from the clean side.
A fleece shortage switch signals that the fleece roll needs to be replaced.

Options

• Emergency overflow channel
• Dirt box
• Fleece separating device that substantially separates the filter cake from the fleece and winds up the fleece
• Can be converted to an endless belt filter at a later date