Mitsubishi Electric Lossnay series Technical Manual page 17

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CHAPTER 1 Ventilation for Healthy Living
4.3 Measuring the Air Volume and Static Pressure
Mitsubishi Electric measures the Lossnay's air volume and static pressure with a device as shown below according to Japan
Industrial Standards (JIS B 8628).
Measuring Device Using Orifice (JIS B 8628 Standards)
Test unit
Blower
Measurement Method
The unit is operated with the throttle device fully closed. There is no air flow at this time, and the air volume is 0. The maximum
point of the static pressure (Point A, the static pressure at this point is called the totally closed pressure) can be obtained. Next,
the throttle device is gradually opened, the auxiliary fan is operated, and the median points (Points B, C and D) are obtained.
Finally, the throttle device is completely opened, and the auxiliary fan is operated until the static pressure in the chamber reaches 0.
The maximum point of the air volume (Point E, the air volume at this point is called the fully opened air volume) is obtained. The
points are connected as shown below, and are expressed as air volume, static pressure curves (Q-H curve).
U-8
Chamber
Smoothing
Supply
net
Air
(SA)
Static pressure in chamber
(Static pressure measurement)
A) When measuring the supply air volume (with the orifice plate)
Wind gauge
duct path Orifice
Smoothing
grid
B) When measuring the return air volume (with the orifice plate)
Air volume ( Q )
Wind gauge
Orifice
duct path
Pressure Smoothing
difference before
and after orifice
(Air volume
measurement)
Return
Air
(RA)
Smoothing
net
Damper
grid
Blower
Test unit
Static pressure in chamber
(Static pressure measurement)