Proline Promass 84F, 84M
22
Hauser
Limiting flow
See "Measuring range" section.
Select nominal diameter by optimising between required flow range and permissible pressure loss. An overview
of max. possible full scale values can be found in the "Measuring range" Section.
• The minimum recommended full scale value is approx. 1/20 of the max. full scale value.
• In most applications, 20 to 50% of the maximum full scale value can be considered ideal.
• Select a lower full scale value for abrasive substances such as fluids with entrained solids
(flow velocity <1 m/s).
• For gas measurement the following rules apply:
– Flow velocity in the measuring tubes should not be more than half the sonic velocity (0.5 Mach).
– The maximum mass flow depends on the density of the gas: formula
Pressure loss in metric units
Pressure loss depends on the properties of the fluid and on its flow.
The following formulas can be used to approximately calculate the pressure loss:
Pressure loss coefficient for Promass F
Reynolds number
a0004623
Re
≥
2300
1)
a0004626
Re < 2300
a0004628
Δ
p = pressure loss [mbar]
ν
= kinematic viscosity [m2/s]
g
= mass flow [kg/s]
ρ
= fluid density [kg/m3]
d = inside diameter of measuring tubes [m]
K to K2 = constants (depending on nominal diameter)
1) To compute the pressure loss for gases, always use the formula for Re
≥
2300.
DN
d[m]
K
K1
K2
8
5.35 · 10
–3
5.70 · 10
7
9.60 · 10
7
1.90 · 10
7
15
8.30 · 10
–3
5.80 · 10
6
1.90 · 10
7
10.60 · 10
5
25
12.00 · 10
–3
1.90 · 10
6
6.40 · 10
6
4.50 · 10
5
40
17.60 · 10
–3
3.50 · 10
5
1.30 · 10
6
1.30 · 10
5
50
26.00 · 10
–3
7.00 · 10
4
5.00 · 10
5
1.40 · 10
4
80
40.50 · 10
–3
1.10 · 10
4
7.71 · 10
4
1.42 · 10
4
100
51.20 · 10
–3
3.54 · 10
3
3.54 · 10
4
5.40 · 10
3
150
68.90 · 10
–3
1.36 · 10
3
2.04 · 10
4
6.46 · 10
2
250
102.26 · 10
–3
3.00 · 10
2
6.10 · 10
3
1.33 · 10
2
Re =
2 ·
g
p
n r
· d ·
·
D
r
p = K ·
·
·
0.25
1.85
–0.86
g
n
D
p = K1 ·
·
+
g
n
K2 ·
·
0.25
2
g
n
r
