Mitsubishi Electric Lossnay series Technical Manual page 88

Gravitational Method
This method is used for air filters that remove coarse dust (0.39 mil (10 µm) or more). The measurement method is determined
by the gravitational ratio of the dust amount on the in-flow and out-flow sides.
Dust collection ratio =
Window
Specimen
Dust collection filter
Colorimetric Method
The in-flow side air and out-flow side air are sampled using a suction pump and passed though filtering paper. The sampled
air is adjusted so that the degree of contamination on both filter papers is the same, and the results are determined by the
sampled air volume ratios on both sides.
Dust collection ratio =
Air-feed fan
Coupling pipe
Throttle device
In-flow side dust amount – Out-flow side dust amount
In-flow side dust amount
Orifice
Dust supply
device
Rectifying grid
Performance test device
Out-flow side sampling amount – In-flow side sampling amount
Out-flow side sampling amount
Coupling
Square duct
pipe
Orifice
Pressure loss concentration
Rectifying grid
measurement position
Round duct
3D 2D 3.5D 2L
Manometer
Motor
Air volume
adjustment plate
Air-feed fan
Example of dust supply device
Rectifying grid
Baffle plate
Coupling pipe
Specimen
7.9(200)
2L
CHAPTER 8
× 100 (%)
Dust container
Mixing blades
Dust supply outlet
× 100 (%)
Venturi pipe
Dust chamber
Air filter
7° or
less
10.5R 3.9R
(267R) (100R)
Unit (inch(mm))
•
Filters
U-79