TM 10-6640-233-10
1-19.
Functional Description of AOAP Mobile Laboratory Unique Equipment. The following paragraphs describe
some of the equipment mounted or stored within the laboratory. For equipment not described in these paragraphs, refer
to the appropriate equipment manual.
a. The fluid analysis spectrometer display (A/E35U-3A) (Figure 1-8) is a 1-meter emission spectrometer with an
LED liquid readout specifically designed for sample oil analysis. It has a console-type equipment cabinet permitting the
operator to carry out the routine procedures of analysis while seated at one location. Except for the main power circuit
breaker control, all operating controls are conveniently within the reach of the operator while in a seated position. Panels
have been designed to permit quick removal and provide access for performing required maintenance. The
spectrometer equipment includes personnel safety features such as safety interlocks, venting of noxious fumes, and
protection from ultraviolet rays. Equipment protective features include circuit breakers, fuse, interlocks, and venting.
Electromagnetic interference is controlled by RFI filters and proper grounding of all electrical components within the
instrument, while critical items have been individually shielded. The sample excitation chamber is interlocked to protect
the operator from high intensity ultraviolet light, shock from the carbon rod/disk are (22,000 volts peak), and exposure to
noxious or flammable fumes while sample analysis is in progress. During normal operation, the carbon arc will totally
"burn" the sample, leaving no residual flammable fumes or vapors. The chamber venting is adequate to purge the
chamber of all noxious or flammable/combustible fumes. The spectrometer is a preventive maintenance tool used to
determine the type and amount of wearmetals in lubrication oil samples of engines/transmissions and in fluids of
hydraulic equipment. The spectrometer is capable of detecting and measuring the concentration of the following
elements:
Iron (Fe)
Nickel (Ni)
Cadmium (Cd)
Silver (Ag)
Lead (Pb)
Molybdenum (Mo)
Aluminum (Al)
Silicon (Si)
Zinc (Zn)
Chromium (Cr)
Tin (Sn)
Sodium (Na)
Copper (Cu)
Titanium (Ti)
Manganese (Mn)
Boron (B)
Magnesium (Mg)
Vanadium (V)
Barium (Ba)
Beryllium (Be)
The operation of the spectrometer is based on the atomic emission technique. This technique depends on the fact that
atoms of elements can be energized (excited) to emit radiant energy when exposed to a suitable excitation source.
When this radiant energy is dispersed by either a prism or a diffraction grating, it emerges as a light spectrum having a
pattern determined by the structure of the atoms that have been excited. Since atoms of different elements contain
different electron configurations, each element has a distinct and characteristic spectrum, with spectral lines occurring at
different wave- lengths. Each element can be identified by its characteristic lines. In quantitative analysis, line
brightness represents element concentration in the sample. Line brightness is converted from radiant energy into
electrical energy by a suitable photomultiplier tube. The electrical signal at the output of the photomultiplier tube is
processed and displayed on a readout device.
The spectrometer can be divided into seven main groups. The groups have been given titles according to their
functions, and with the exception of a few items, assemblies and subassemblies are physically located in the cabinet or
chassis of their respective groups. The groups are as follows:
a. Sample excitation group
e.
Integration group
b. Optical processing group
f.
Power distribution group
c. Control group
g.
Optional group (automatic printer)
d. Electronic processing group
1-21
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