Start of operation
198
Measuring System MAK TIGER 3003 Service manual, SA 131128, 10.03.2020
The pump delivery at the maximum frequency of 10 kHz is as follows:
25*0.27 ml = 6.75 ml per second.
The starting and braking time of the stepper motor is approx. 0.5 seconds.
Time required (pump threshold limit)
to fill one sample bottle with 35 ml
to 100 %:
35 / 6.75 + 0.5 sec = 5.7 sec.
In order to obtain a representative sample, therefore, the intake process
must not be shorter than 5.7 seconds.
If the pre-rinse function is activated, the pre-rinse time of approx. 0.5 sec-
onds must be added to this time.
Basis for calculation:
Pressure:
Approx. 0.3 bar
Calibration factor (hose): Approx. 270
Sample bottle volume:
35 ml
Flow-calming section:
≥ 3 x NW (NW50 = 150 mm, NW76 = 228 mm)
Taking these figures as a reference, the following table can be used as an
approximate guide at minimum intake quantity:
Intake quantity
Max. throughput
Without pre-rinse
Max. throughput
With pre-rinse
20 l
200 l/min
180 l/min
40 l
400 l/min
380 l/min
80 l
800 l/min
760 l/min
160 l
1600 l/min
1520 l/min
Note:
It is relatively difficult to operate the intake pump at different levels there-
fore it is possible to use the low output for 20 l and 40 l, for example, and
the high output for the other quantities.
In any case there must be provision for at least a single-stage reduction of
throughput.
If the restrictor is activated for a certain time, this time must be selected so
that the entire intake process is completed with this restricted output, i.e. a
time setting of at least 6 seconds is required at a throughput of 200 l/min.
The system is actuated automatically via an output on the MAK 3003 data
logging system at pre-sample setting and intake quantity < 80 l.
The suction capacity with small intake quantities is continually increased
and is greatest at the end therefore the throughput of the system should
not be taken to the performance limit of the sampler as it is then no longer
possible to adjust power peaks and therefore the required representative-
ness cannot be achieved.