Gas and Process Sample Transport Systems for Analyzer Applications













NEW! TrueTube test data is now available.

The new test data set includes:

  • Relative response time of TrueTube when measuring moisture content in sample stream.
  • Electropolished Silica Steel coated tubing on adsorption of methylmercaptane.
  • Study of 6N HCI corrosion on commercial 316 SS, Hastelloy C-22 and TrueTube variants
  • Application of TrueTube in analytical measurement

TrueTube is a family of tubing products developed to provide best-of-breed performance in sample transport for process and emissions analyzers. O'Brien Analytical starts with select ASTM grade tubing and enhances its physical characteristics to improve dry-down, adsorption and corrosion resistance. We do this by controlling surface roughness, cleanliness, surface chmistry and reactive contaminants.

Surface Roughness
Surface roughness contributes to adsorption / desorption problems associated with analyzer sample lines. The microphotographs below illustrate one of the differences in tube material and selection. Surface roughness is only one factor to consider when specifying sample tube material. However, like other choices in sample system components, it can improve or limit the repeatable accuracy of the entire system.

Cleanliness and Reactive Contaminants
The O’Brien Analytical TrueTube process removes drawing oils and other contaminants that are often present in commercial grade tubing. At the same time surface iron is removed and the tube is left with an enriched Cr/Fe and CrO/FeO ratio which contributes to corrosion resistance.

500x Seamless 316L SS Tubing
Because of differences in manufacturing processes the surface roughness of commercial grade seamless tubing can vary widely. Commercial grade seamless tubing often has a higher surface roughness than a similar welded tube.
500x Welded 316L SS Tubing
The forming operations used to manufacture welded tubing produce a higher surface roughness. Because the weld area is considered inhomogeneous it is more susceptible to corrosion, particularly pitting. Besides limiting the life of the installation corrosion also creates additional sites for the sample to “hang up” or collect.
500x TrueTube FS
A secondary process creates a fused silica lining on base 316L seamless stainless steel tubing. The fused silica coating improves surface roughness, corrosion resistance and reduces the affinity of stainless steel to many compounds such as H2S. Fused silica lined tubes have found acceptance for transporting low sulfur samples.

500x TrueTube CP
TrueTube CP is chemically polished 316L seamless tubing with an improved surface roughness. During the process free iron molecules are removed from the inner surface of the tubing and it is cleaned of all hydrocarbon drawing compounds used when the base tube was manufactured. Notice the absence of crevices and valleys where particles can lodge or attach.

TrueTube CP is also available in long continuous coils.
500x TrueTube EP
The photo illustrates the superior surface finish achieved by electropolished TrueTube. Electropolishing not only improves surface roughness but also provides enhanced corrosion resistance by leaving a chromium enriched surface layer. TrueTube EP provides improved corrosion resistance and reduced dry-down time, making it the smoothest tube we offer.

TrueTube EP is also available in long continuous coils.
  TrueTube EPS
The ultimate product for corrosion resistance and aversion to sulfur compounds. TrueTube EPS combines the advantages of electropolished and fused silica coated tubing to produce a superior tube.

Specialty Cleaning
O’Brien Analytical also provides thermocouple and CFOS cleaning for commercial grade tubing.

Thermocouple Cleaned
Thermocouple cleaned tubing is free of all drawing compounds, carbon, dirt, dust and other contaminants. After cleaning a swatch of lint-free cloth soaked in acetone is passed through the tube to verify cleanliness to ASTM A632-S3. The tubing is then capped to prevent contamination.

CFOS
O’Brien Analytical can also supply tubing which has been cleaned for oxygen service per ASTM G93A Level A and CGA G-4.1 requirements. After cleaning the tubing is capped to prevent contamination.

Orbital Weld Fittings and Tubing
We also offer specialty tube and orbital weld fittings from our sister company Cardinal Systems. Cardinal is a provider of high purity and ultra high purity tubing and fittings to the biopharm, medical, pharmaceutical and semiconductor industries. These products are available in sizes from 1/4" through 6". Tubing is provided in 20' straight sticks.

Orbital weld fittings eliminate the dead space and crevices associated with compression fittings so there is no place for sample stream components to collect and become entrapped.


O’Brien Analytical also offers specialty tube and orbital weld fittings through our sister company Cardinal Systems a provider of high purity and ultra high purity tubing and fittings to the biopharm, medical, pharmaceutical and semiconductor industries. These products are available in sizes from 1/4" through 6". Tubing is provided in 20' straight sticks.

Tech 5 Tubing
• High quality seamless and welded 316L SS.
• Thermocouple cleaned per ASTM 632 Supplement S3.
• Purged with filtered nitrogen and capped.
Tech 10 Tubing
• High quality seamless 316L SS.
• Exceeds CFOS CGA G4.1 cleaning.
• Fully passivated with nitric acid.
• Rinsed with DI water, purged with filtered nitrogen and capped.
Tech 20 Tubing
• Chemically polished
• High quality seamless 316L SS.
• Low particulate cleaning.
• Fully passivated with nitric acid.
• Final rinse with heated 18 megohm DI water, purged with filtered nitrogen until dry and capped.
• Final cleaning and packaging performed in a cleanroom.
Tech 25 Electropolished Tubing
• Electropolished
• 316L SS tubing meets ASTM specifications for consistent physical, dimensional and chemical composition.
• Restricted sulfur content insures low non- metallic inclusions.
• Final cleaning and packaging performed in a Federal Standard 209 Class 10 cleanroom.
• 0.1µ filtered 18 megohm 60°C deionized water rinse until effluent surpasses 17.5 megohm.
• Dried with 0.005 µ filtered 120°C nitrogen and capped.

Integrated Solutions Improving Process Accuracy

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