Endress+Hauser Proservo NMS5 Operating Instructions Manual page 53

Proservo NMS5
Endress+Hauser
Densities
The upper, middle, and bottom densities are calculated by the following formulas.
• Upper density (Pu) and Density profile
ρ
u =
• Middle density (Pm)
ρ
m =
• Bottom density (Pb)
ρ
b =
Draft
The draft varies depending on the shape of the displacer. For cylindrical shape, the draft is
D (V
=
where the variables and constants have the following meanings.
(V - V - V ) / A x 10 + h + h
=
1 2 3
V
Displacer Balance Volume (69cm
1
V
Displacer Lower Hemisphere Volume
2
V
Displacer Bottom Stub Volume
3
A
Cross-section of Displacer
h Height of Lower Cone
Height of End of Cone
h
1
For example: standard displacer
V
Balance Volume (69 cm
1
V
Volume of Lower Cone (24.46 cm
2
V Volume of End of Cone (0.12 cm
3
A Cross-section of Displacer (20.26 cm
h
Displacer Bottom Stub Height (20 mm)
1
D = (69 - 24.46 - 0.12) / 20.26 x 10 + 20 + 3
= 44.92
Figure. 57: Variables and Constants for Displacer
The surface or interface level should be within the cylindrical part of the displacer and approximately in the
middle of its total height.
W - W
u
V
W - W
u m
ρ
+
V
W - W
m b
ρ
+
V
- V ) / A x 10 + h
2 1
1
3
)
Ø50.8 mm Cylindrical shape
3
)
3
)
3
)
2
)
u
m
Liquid Level or Interface
V h
2
V
3
h
1
d
6 Operation
D
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