Pump Overloading - Cole-Parmer Carter manostat 74-046-00000 Manual De Operación

(a) Normal Occlusion Settings
The following table shows the appropriate occlusion settings to provide satisfactory performance for various
tubing sizes. (For optimum occlusion settings, see following section.)
TABLE 3 RECOMMENDED OCCLUSION SETTINGS
Tubing Link Large Cassette Scale Small Cassette Scale
MANOSTAT Microbore N/A #3
N/A
MANOSTAT size 13, 14, 16, 25, 17, 18 #3 - #4
(b) Occlusion Setting Procedure:
1. Select the recommended occlusion value from the table.
2. Turn the Occlusion Adjustment Knob to align the inside edge of the white Wedge with the scale number. (Clockwise
rotation increases the occlusion.)
(c) Optimized Occlusion Settings
Some applications require additional fine-tuning of the occlusion setting to vary the flow rate for a particular tubing, to
reduce flow variations caused by changes in system pressure, or to increase tubing life.
1. Adjust the Occlusion Wedges as described in the preceding table.
2. Refine this setting, depending upon your objectives:
NOTE: To Maximize Tubing Life
While running the pump, simply reduce the adjusted occlusion setting by turning the Occlusion Adjustment Knob
counterclockwise to move the wedges to a higher setpoint scale number (toward 5). Continue turning the knob
counter-clockwise until the flow drop-off or the pressure sensitivity becomes unacceptable, then turn knob slightly
clockwise.
NOTE: To Reduce or Eliminate Flow Drop-Off Rate with Pressure Fluctuations
While running the pump alternate the backpressure between the expected high and low values and increase the
adjusted occlusion setting. Turn the Occlusion Adjustment Knob clockwise to move the wedges to a lower setpoint
scale number (toward 1) until the flow drop-off is minimized.
NOTE: To Fine Adjust the Flow Rate
Increase or decrease the occlusion value to vary the flow.

(5) Pump Overloading

Models 74-126-00000 and 74-128-00000 have an auto-resetting limit clutch built in to protect the Pump and Drive in the
event of excessive loading. When an overload occurs the pump rotor will top rotating and the clutch will emit an audible
clatter. The clutch capacity is sufficient to drive most combinations of tubing size and material at any pump speed with a
full complement of channels operating. Sokme larger sizes of stiff tubings pumping through tight occlusion settings at
higher speeds will cause an overload condition. This will limit the number of channels which can be run.
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