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3 Pump Inspection and Calibration
3.1 Pressure tests (pressure ramp and holding tests)
Although the final test of pump operations involves checking the chromatogram
(baseline) when the injector, column, detector, and other units are connected, the
tests described in this section are simple and can be performed using the only pump.
Be sure to perform the tests described in this section after replacing pump parts (for
example, the plunger seal or purge valve needle).
3.1.1 Preparation
Replace the solvent inside the pump with one of the following solvents (See Section
4.2):
y
Methanol
y
Water
Since the pump section may develop a leak during the pressure test, a solvent or
liquid which is harmless to humans must be used. If organic solvents are currently
being used, replace these solvents with methanol. If a buffer solution or other
solution containing salts is being used, replace this solution with water.
WARNING
: Chloroform and acetonitrile are hazardous to the human body and
should not be used for the pressure test.
CAUTION: Since, salts in buffers may precipitate, causing poor instrument
performance, do not use buffers for the pressure test.
Note: Since water tends to leave air bubbles in the pump head, be sure that any
water used for the pressure test has been sufficiently degassed.
3.1.2 Pressure Test 1 (pressure ramp test)
(1) Screw a male plug into the outlet port and tighten firmly using a wrench.
(2) Tighten the purge valve firmly.
(3) Set the flow rate to 0.1 ml/min and the maximum pressure to 50.0 MPa.
(4) Begin solvent delivery.
Monitor the pressure on the LCD panel during pumping operations. The pump
is operating normally if the pressure increases continuously to 50.0 MPa,
without dropping before reaching the maximum pressure. The pump should
then stop and OVER PRESS should appear on the display.
(5) The pressure will not reach 50.0 MPa if a large leak exists. If this happens,
refer to Fig. 2.2, isolate the leak, and then refer to Section 2.4 to identify the
appropriate method for dealing with the leak.