Typical Nutsche Filter Media
Nutsche filters are indispensable
in pharmaceutical and fine chemical research and development and production
operations. The Nutsche’s ability to wash, slurry and dry the filter cake
and operate at high pressure or vacuum, provides a versatile service.
Most Nutsches also have an agitator or “paddle” for enhanced mixing and
to frequently facilitate cake removal. These features, abilities and enhancements
often require a rugged filer medium to withstand the harsh dynamic environment.
Some Nutsches use a single
layer of fine wire mesh as the filtration medium. The un-sintered mesh
is stretched across a frame and locked into place. Stretching of course
places both the warp and weft wires in the mesh in tension and the result
is a definite change in mean pore size. To reduce valuable product loss,
heels are kept to a minimum. Often, the agitator (or plow)
lower stop limit is set to as low as 6 mm. Many un-sintered single layer
meshes have been destroyed by the high shearing & tangential forces
caused by the rotating filter cake during mixing as the paddle descended
to its lower stop limit.
Sintered metal powder media,
while mechanically superior to single layer wire mesh, are unable to be
efficiently backwashed due to their tortuous path isotropy and are poor
choices for the Nutsche. Thus, the ideal filtration medium should feature:
- A wide range of operating-temperatures & pressures
- Permanent, uniform pore size
- Corrosion Resistance
- Wear Resistance & Mechanical Strength
- Cleanable by Backwashing
- Surface, not Depth, Filtration
Dynapore® Is The Answer
The diffusion-bonded multiple layer construction
of Dynapore® offers every advantage. From strength and durability
to the cleanability of an engineered surface filtration medium, Dynapore®
is the number one choice of most OEMs. Dynapore® Nutsche filter
media are available in type 316L stainless steel and Hastelloy® C-22
in standard 5-layer TWM™ construction and Hi-Flo
BWM™ construction. Custom constructions are available on request.
MKI offers complete
fabrication services to replace or recondition your existing Nutsche
filter plate assemblies. Simply call us to discuss your needs.