Environnement MP101M, Техническое руководство

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Duplication prohibited
MP101M
Environnement
S.A
2–7
SEPTEMBER 2013
The internal sensors of temperature and pressure coupled with the meterological sensors of regulated
sampling tube (RST) line enable to measure the “volumetric” flow rate in the atmospheric conditions:
The flow rate is thus controlled and maintained constant to the nominal setting value (1 m
3
/h) at level
of sampling head. That is essential in order to ensure the correct granulometric separation of the
particles through the head and the precise calculation of sampled volume in atmospheric conditions.
The flow of a fluid through a critical orifice is given by the following equation, in case of an
homogenous, not turbulent flow :
















 
2
1
2
2
1 *
2
S
S
P
S Q

(1)
Where :

P = P
1
– P
2
is the difference between the pressures measured upstream and downstream the orifice,
S
1
and S
2
are the surfaces of the two orifice sections.

is the air density at P
1
pressure and T
1
temperature, with
1
0
0
1
0
* *
T
T
P
P
 

.
As S
1
, S
2,
P
0
(reference pressure = 1013.33 mbar) and T
0
(reference temperature = 273.15K) are
constants, consequently it is possible to write the flow at level of the orifice flowrate ( Q
flowmeter
) under
the form :
1
1
*
*
P
T P
K Q
flowmeter


(2)
Where K is a constant which is possible to define by calibration (in the « CALIBRATION

Flow
rate » ).
Case when the regulated sampling tube (RST) option is activated :
The flow rate, into the atmospheric conditions, is automatically calculated by the analyzer, in the
following way :
atm
atm
atm
atm
atm
P
T
T
P P
K
P
T
T
P
P
T P
K Q *
*
* * *
*
*
1
1
1
1
1
1




(3)
Where T
atm
and P
atm
respectively are the temperature and the atmospheric pressure measured
continuously.
NOTE : In the previous equations, the T
atm
and T
1
temperatures are stated in Kelvin degrees.