Abstract: A filter pump head assembly (10) is adapted for use with pneumatic pumping control systems. The assembly includes a rigid case subassembly (12) enclosing a chemically inert liner subassembly (14) which encloses a filter subassembly (16). The liner subassembly (14) includes a pneumatically deformable pumping membrane (72), the deformation of which varies the volume surrounding a filter cartridge (112). Various valves (33, 34 and 35) and ports are operated by selective pneumatic pressure on a top membrane (68). The control block (80) includes a bubble capture channel (94) which allows the bleeding of undesirable gas bubbles during use. The invention pump of the various disclosed embodiments is particularly adapted to pump and filter ultrapure, reactive fluids varying viscosities at a low pumping pressure. The primary current commercial usage of the invention is in the semiconductor manufacturing industry.