Seepex BN 5-12 Series, Руководство по эксплуатации и техническому обслуживанию

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8
The essential difference between the individual geometries
can best be represented by the following formulas.
The theoretical conveying capacity of the 6L and the
conventional geometry is calculated as follows:
The following formula is used for the Tricam geometry:
For the single helix rotor geometries, Q
th
(m 3 /h), along with
the rotation speed n [min –1 ], is thus a function of e [m] rotor
eccentricity, d [m] rotor diameter, and s [m] rotor pitch.
Q
th
is the same for the double helix rotor geometries shown,
as the smaller rotor eccentricity and smaller rotor diameter are
equalized by the greater pitch. In other words, the same speed
results in the same theoretical conveying capacity.
The theoretical conveying capacity of the 2/3 speed geometries
(Tricam) is a function depending on the conveying surface (A)
multiplied by the stator pitch (S
S
) and the eccentric speed.
The flow rate of the Tricam geometry is twice as great as the
standard geometries at the same speed. On each rotor revolu-
tion all conveying chambers are evacuated twice. Despite the
smaller conveying chambers, this leads to a 50 % increase of
the conveying capacity.
The Tricam geometry has on average a roughly 14 % higher
surface velocity. Thanks to the above-mentioned capacity
increase, it is possible, with a slight speed reduction, to have
a lower surface velocity and still maintain a higher conveying
capacity compared to the single helix geometries.
Wear and tear on the main pump elements, rotor and stator,
is essentially determined by the surface velocity of the rotor,
the effective forces and the properties of the conveying prod-
uct and the resistance to erosion of the materials used for the
rotor and stator. Due to the motion sequence there are three
values for the surface velocity.
Q
th
= A · S
S
· n · 2 · 60 · 10 -9
The geometries in detail: 6L, conventional, Tricam.
Conventional geometry, multi-stage
Tricam geometry (-6LT), single stage
Tricam geometry (T), multi-stage
6L geometry, single stage
Q
th
= 4e · d · 2s · n · 60
A =
(d
R
+ 4e) 2 · π – D
R
· d
R
· π
4
π · n [min –1 ] · (d – 4e[mm])
1000 · 60
π · n [min –1 ] · (d + 4e[mm])
1000 · 60
V
min
[m/sec] =
V
max
[m/sec] =
V
g
median
[m/sec] =
π · n [min –1 ] · (d
R
+ 2e)
1000 · 60