Teledyne 3060e - Ultra Trace oxygen analyzer - Manual (Page 18)

2-8
Model 3060E Model 3060E Model 3060E Model 3060E Model 3060E Chapter 2 Chapter 2 Chapter 2 Chapter 2 Chapter 2
Teledyne Electronic Technologies
Analytical Instruments
Sample System
The sample system delivers gases to the O
2
sensor from the analyzer rear panel
inlet. Depending on the mode of operation (determined by which valves are
open or closed), either a sample, span or zero gas is delivered.
The 3060E sample system is designed and fabricated to insure that the O
2
concentration of the gas is not altered (except in the O
2
scrubber) as it travels
through the sample system.
• Electropolished 316L Stainless Steel Components
To eliminate O
2
absorption and desorption from the internal wetted
surfaces of the sample system components, the sample system is
fabricated from electropolished 316L stainless steel.
• Welding/Metal Gasket-Type Fittings
All of the joints upstream of the O
2
sensor are orbitally welded,
except for the metal gasket-type compression connections at the O
2
scrubber and mass flow controller. Orbital welding is used in the
sample system wherever feasible. Orbital welding fuses the elec-
tropolished 316L stainless steel components together, forming a
smooth, clean internal (wetted) weld junction and eliminating small
spaces around the weld junction where gases can get trapped or
absorbed. All of the weld junctions in the entire assembly are
purged using an inert gas during welding to ensure that there is no
O
2
contamination.
Orbital welding is used where practical; otherwise, conventional
precision welding is used. For example, conventional precision
welding is used to fuse the tubes to the mounting plates. Metal
gasket-type compression connections are used at the O
2
scrubber
and at the mass flow controller to facilitate replacement. The metal
gasket-type connection creates an airtight, metal-to-metal seal,
eliminating inboard and outboard gas leakage.