5
Functional description
5.1 Pump
The metering pump is an oscillating diaphragm pump, the stroke length of
which can be adjusted. An electric motor drives it. The slide rod transmits
the stoke motion to the diaphragms.
The stroke movement of the displacement body is continuously detected
and regulated so that the stroke is performed according to a previously set
metering profile - see chapter.
‘Metering’
‘setting’
.
The following metering profiles are available:
n
Normal
n
Metering optimised
n
Priming optimised
Every metering profile is ineffective below the switch-
over frequency for Start/Stop mode.
Normal
0
s
s
a)
180
360
0
b)
180
360
ω
ω
P_PL_0009_SW
Fig. 8: Stroke movement at a) maximum stroke length and b) reduced
stroke length.
s
Stroke velocity
⍵ Cam rotational angle
+ Discharge stroke
-
Suction stroke
Metering optimised
With a metering optimised metering profile, the discharge stroke is elon‐
gated and the suction stroke is executed as quickly as possible. This set‐
ting is for example suitable for those applications that require optimum
mixing ratios and the most continuous chemical mixing possible.
Priming optimised
Illustration of the stroke movement
P_SI_0120_SW
s
t
P_SI_0103_SW
s
t
Functional description
18
Summary of Contents for Sigma 1 S1Cb
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