Gas Flow; System Components - Ametek 5000 Instrument Manual

Gas Flow

(Figure 2)
Gas flows in three separate streams through the system: sample gas, reference gas, and moisture
generator gas. Flow rate through the cell (for whichever gas is present) is controlled by flow control
needle valves and indicated by a flowmeter at the cell exhaust. A pressure gauge is also located at
the exhaust port to ensure analyzer operation at a back pressure of 103 kPa (15 psi) gauge; this per-
mits exhausting to a pressurized vent.
Four solenoid valves (L
below. Note that energized valves are in the normally closed contacts (NC) position and de-ener-
gized valves are in the normally open contacts (NO) position:
Normal Operation:
• Sample gas flow (ƒ
L is energized and L
1
energized (open contacts) so reference and moisture generator gases are exhausted.
• Reference gas flow (ƒ
L and L remain de-energized. L
3 4
cell and sample gas is exhausted.
Auto or Manual Verification:
• Moisture Generator gas flow (ƒ
L and L are energized so sample bypasses L
3 4
is energized so moisture generator gas flows to the cell. L
exhausted.
• Reference gas flow (ƒ
L and L remain energized. L
3 4
moisture generator gas is exhausted.

System Components

A typical 5000 Moisture Analyzer system is comprised of an explosion-proof 5000 field unit, sample
drying and filtering equipment, and a remote 5000 Microprocessor Controller.
Field Unit
(Figure 3)
Components contained in the fi eld unit:
• Sample cell contained in an oven and maintained at 60°C
• Sample and reference solenoid valves (L
• Moisture generator
• Moisture generator solenoid valves (L
• Power and electronics control card
• Power transformer (not shown)
• Internal heater and 40°C thermostat (not shown)
• H2S scrubber (optional, not shown)
1-4 5000 Multi Point Moisture Analyzer
) are switched by the controller to control gas flow to the cell as described
1-4
measurement)
sample
is de-energized so sample gas flows to the cell. L
4
measurement)
ref
and L
1
measurement)
cal
measurement)
ref
and L
1 2
, L
1 2
, L )
3 4
toggle such that reference gas flows through the
2
to exhaust port and calibration gas flows to L
1
is de-energized so reference gas is
2
toggle such that reference gas flows through the cell and
)
and L are de-
2 3
. L
1 1