Vacuum Filtration

About Vacuum and Pressure Filtration

Vacuum and pressure filtration is used for sample preparation in chemistry, life sciences, environmental analysis, and pharmaceutical quality control. The goal is to separate a solid product from a liquid mixture or solvent. Filtration rates are accelerated by creating a differential pressure across the filter unit by applying either vacuum or pressure. 

Aqueous to Mild Chemical Duty Pumps

• Flow rates available meet number of filter holders
• Range of built-in accessories and head/diaphragm materials
• Models for pressure filtration
• Type to meet your application and budget needs

The WOB-L® oil-free vacuum pumps employ an aluminum piston with PTFE seal and are loaded with powerful features for vacuum or pressure filtration. The diaphragm pumps are available in different head/diaphragm materials to handle a range of chemical vapors evolved during filtrations. 

With these two pump mechanisms and range of materials available, Welch can offer a pump to fit your specific application and budget needs. A modest vacuum of 40 torr (53 mbar) to 200 torr (266 mbar) is normally sufficient (26 in. Hg to 29.6 in. Hg) for most vacuum filtration applications. 

Free air displacement requirement for vacuum filtration is dependent on the filter size, leak rate, condition of the filter cake, and number of filter holders. Pressure filtration normally requires from 2 to 6 bar (30 PSIG to 88 PSIG).