Baseline Noise - Hitachi L-8900 Service Manual

Trouble Check Point
Pump unit (common)
Filter in Reagent bottle
(common)
Pressure of only Pump 1
(or Pump 2) does not
increase, or fluctuates.
Injection valve of
Autosampler (only Pump 1)

3.1.2 Baseline Noise

1. Noise test value is
abnormally high.
N gas pressure
2
CH1: 50 or more
CH2: 100 or more
2. Noise appears on
chromatogram
Pump unit
Flow path filter
Line filter
Photometer lamp
Photometer cell
Cause
Bubbles generated
in Pump valve.
Dirty Pump valve
(Seal dust).
Life of Pump seal.
Filter clogged
(Reagent dust
stuck)
Filter
Life of Rotor seal.
If pressure is lower than 34 - 40
N gas
2
kPa (0.35 - 0.4 kgf/cm
pressure
turn Regulator knob clockwise to
lowered.
adjust.
Bubbles generated
in Pump valve.
Check Pump pressure value on
Seal dust in Pump Monitor screen whether or not it
valve.
fluctuates 1 MPA (10 kgf/cm
or more.
Life of seal
(leakage)
Remove Flow path filter from
Clogging by
Pump, check Filter visually.
Pump seal dust Check black seal dust stuck or
not.
Clogging by
impurities in
samples, injection
port seal dust of
Autosampler.
Check running time.
Deterioration
(Maintenance screen on CRT)
Dirt, bubbles
Result
Check
Open Drain valve and purge.
Disassemble and clean Suction valve,
Discharge valve, and pump head.
Replace Pump seal (life is about 1 month).
Clean Filter with an ultrasonic cleaner, or
replace Filter.
Replace Rotor seal.
Make pressure supplied
by N
Pressure low
0.1 MPa (0.5 - 1.0
2
) range, kgf/cm
Pressure normal.
Open Drain valve and purge.
Disassemble and clean Suction valve,
2
) Discharge valve, and Pump head.
Replace Seal (life is about 1 month).
Clean Flow path filter with an ultrasonic
cleaner.
Remove Filter from Filter body, and clean it
with an ultrasonic cleaner.
Cleaning solution to be used is
water Ethanol Distilled water in this
If running time is 1,000 hours or more,
replace it.
Remove the tube from Reaction column
outlet, connect an injector. Inject distilled
water, acetone, distilled water in this order to
clean the cell. (Inject 5 mL of each).
Remedy Remarks
See 6.3.1 or 6.3.5 for cleaning way.
See 6.3.1 Replacing way for Pump seal.
See 6.3.4 Replacing way for Filter.
See 6.3.9 Replacing way fro Rotor seal.
gas cylinder 0.05 -
If pressure of N gas unit is low, the Pump suction side becomes negative pressure, and bubbles
2 2
are generated in Pump, so, pumping liquid becomes unstable to cause Baseline noise.
2
).
OK.
1. Clean Pump head (with Suction valve and Discharge valve attached) with and ultrasonic
cleaner (with distilled water).
2. If bubbles cannot be removed by the above two items, remove Suction valve and clean them
with an ultrasonic cleaner (with neutral detergent solution). See 6.3.1 Cleaning way for details
and cautions.
1. Clogging of Line filter may cause pressure increase of buffer solution pump. Clean it as
occasion demands, replace it regularly (about 6 months).
Distilled 2. To prevent clogging of Line filer and Column, pass samples through 0.45 µm filter without fail.
See 6.3.6 Lamp replacement for replacing Lamp.
3 - 2