Membrane dryer for compressed air

Innovative, compact dryers for superior efficiency and reliability

The Kaeser Modular Membrane Dryer (KMM) produces pressure dew points to -40°F. It is perfect for small to medium compressed air systems. KMMs do not require electricity or cooling water, which simplifies installation even in existing systems. They are particularly effective in reaching low pressure dew points when used with a refrigerated dryer and installed at the point of use.

Efficiency and Dependability

The KMM dryer provides many advantages over conventional membrane dryer models. The "inflow" design ensures outstanding drying results by effectively removing moisture, enhancing pressure stability and reducing pressure differential. The welded aluminum housing and epoxy powder coating provide durability in harsh environments.  Its lightweight design requires no additional support structure, and the space-saving modular design connects easily to prefilters and afterfilters. In-line filters are recommended with a KMM to prevent contaminants from reaching the sensitive membrane fibres.


Product details

Outstanding membrane design

Super-fine membrane fibers

KMM membrane dryer – the finest membrane fibres

Compared to conventional membrane fiber dryers, the fibers in the Kaeser membrane module many more fibers that are significantly finer, thereby increasing their surface area. In turn, this delivers superior drying performance compared to conventional designs. The high mechanical stability of the membrane fibers also helps ensure superior performance.

Flow concept

KMM membrane dryer – the “flow” concept

The hollow membrane fibers consist of a highly porous support layer and an internal, water-permeable separation layer. The pressure differential between the moist compressed air outside the fiber and the almost atmospheric flow of purge air through the center encourages water molecules to permeate through the fiber wall. As a result, the pores of the support layer always remain permeable.

Efficient drying

KMM membrane dryer – efficient drying

The spiral helical structure of the fibers in the inner chamber of the dryer module means that the module is now shorter, yet has the same drying capacity as previous, longer models – while still achieving a greater active membrane surface area per unit of volume. The helical fiber structure also promotes even distribution of air around the fibers and encourages the movement of water molecules.

Versions and options

KMM with purge air stop valve for even greater energy savings

  • KMM membrane module with flow concept and helical fibre structure
  • Solenoid pilot-valve: 230 V, 50 Hz, 240 V, 60 Hz, open when de-energized
  • Configured and pre-assembled for immediate use.
  • Outlet silencer also included
Function of the membrane dryer module
Function of the membrane dryer module
  1. Compressed air inlet
  2. Membrane fibre module
  3. External casing
  4. Purge air nozzle
  5. Purge air outlet
  6. Compressed air outlet

Moist compressed air flows into the module casing, where it comes into contact with the membrane fibers. A minimal amount of this now dry compressed air is used as purge air and is drawn upwards around the fibers and expands to atmospheric pressure. The resulting increase in volume increases the air’s water retention capacity. In combination with with the selectivity of the membrane, the differing water content of the purge air flow and the flow of air to be dried (both flowing in opposite directions), allows water molecules - almost exclusively - to diffuse through the fiber wall. There are separate outlets for the dried compressed air and the purge air.

Technical specifications

The technical specifications can be found in this brochure: