Primary Plate; Actuating Subassemblies; Operation; Detector Subsystem - Emerson Daniel Danalyzer 1000 Hardware Reference Manual

SEP 2005
2.2.2.1

Primary Plate

The primary plate contains precisely machined internal passages that enter and exit the valve at top
ports, each of which is connected to the top and/or bottom of the plate within the valve. The
primary plate, which is the only metallic element that comes in contact with the sample, is isolated
from the remainder of the valve by specially formulated diaphragms.
GC valve should be torqued to 30 Ft. lbs.
2.2.2.2

Actuating Subassemblies

Below the primary plate, pistons are operated by pneumatic pressure applied to actuating diaphragms
through ports in the base plate.
2.2.2.3

Operation

When pneumatic pressure is applied to the actuating diaphragms, the pistons are actuated, thus
forcing the sealing diaphragm against the primary plate. This closes the passages that are connected
at the bottom of the plate. When pressure is removed, the pistons are free to move, and flow is
resumed through the passages.
2.2.3

Detector Subsystem

The operation of the Analyzer detector subsystem was previously discussed in the "Theory of
Operation" section of this manual.
2.2.4

Analyzer Preamplifier Unit

The electrical output from the detector is amplified by the Analyzer preamplifier unit. The
preamplifier also supplies drive current to the detector bridge. The voltage signal is converted to a
4 to 20-milliamp (mA) current loop for transmission to the GC Controller. The signal is proportional
to the concentration of a component detected in the gas sample. The preamplifier provides four
different gain channels and compensates for baseline drift. The signals from the preamplifier are
then sent to the GC Controller, where they provide the basis for analysis computations and a
chromatographic trace, or chromatogram.
2-8
MODEL 1000
EQUIPMENT DESCRIPTION