Powder unit

Powder unit

A powder unit is a workstation for weighing raw materials and taking samples of them. The Kojair powder unit protects the operator and environment. The dimensions, number of filtration steps and materials of a powder unit are designed according to your needs, and it offers almost endless opportunities for customization.
Some options are:

  • Light fixtures
  • Half speed function
  • One to four filtration steps
  • Side walls or curtains
  • Velocity gauge and alarm functions
  • Fresh air connection
  • Built-in cooling or heating element
  • Interlocking with general ventilation
  • Air curtain can be included to ensure free entrance to the working area

Kojair powder unit offers almost endless customization possibilities








Function of the powder unit

Air normally recirculates in the module through three sets of filters. Air circulates through grilles close to the floor in the back wall of the work chamber. The first filtering step takes place after the grilles. The class of filters used is EU3 – EU5. The majority of visible particles are filtered in this step. The next filtering step is EU6 – EU9 where the rest of the visible particles and a large portion of the smaller particles are filtered.
After this, air is blown into a plenum through fans. The bottom of the plenum (ceiling of the work chamber) is built out of EU13 – EU14 HEPA filters. Air streams through HEPA filters and parallely down through the work chamber. The parallel (laminar) air flow effectively keeps the work chamber clean and free of particles. A small volume of air is exhausted from the circulation through a small HEPA -filter on top of the plenum (or on the side). The same volume of air is taken in from the ventilation system of the building or directly from the ambient air.

Regulation and controls powder unit

The air velocity under the HEPA filters is 0.3 – 0.4 m/s. Light fixtures can be located between the HEPA filters or on the sides of the filter area. HEPA filters can be protected against physical damage by installing protective grilles under the filters. The side walls of the work chamber can be made of metal or plastic. Plastic curtains or an air curtain can form the front wall of the work chamber (or side wall if access to work chamber is required from the side). The air velocity of the air curtain is 2 – 5 m/s.

Construction and materials of the powder unit

The effect of the fans (both the recirculation fans and the air curtain fan) are steplessly regulated. Switches and potentiometers are built into the back wall of the work chamber. The first two filtering steps have analogue manometers for controlling pressure drop. Air flow under the HEPA filters is controlled with an electronic velocity gauge which sounds an alarm if the flow is too low.

For more information about the Kojair powder units please contact your area sales manager, click here