TrueTube®

  • High Performance Tubing for Process and Emissions Analyzers +


    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 chemistry 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.


    500x
    Welded Seamless 316L Stainless Steel 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
    Seamless 316L Stainless Steel 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
    TrueTube® CP
    TrueTube CP is chemically polished and passivated 316L seamless tubing with improved characteristics. During the process free iron molecules are removed from the inner surface of the tubing and all hydrocarbon drawing compounds are removed. This enhances the normal Cr/Fe and CrO/FeO surface layer improving corrosion resistance and reducing chemical reactivity.
    TrueTube CP is also available in long continuous coils.


    500x
    TrueTube® FS
    A secondary process adds SilcoNert™ 2000 fused silica coating, on the ID of TrueTube CP base tubing. TrueTube FS demonstrates improved corrosion resistance and reduces the affinity of stainless steel to many compounds such as H2S. It has found acceptance for transporting sulfur samples.


    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.


    500x
    TrueTube® EPS
    The ultimate product for corrosion resistance and aversion to sulfur compounds. TrueTube EPS combines the advantages of electropolished tubing and SilcoTek’s SilcoNert 2000 coating. The electropolished tube provides the ideal substrate for the CVD applied coating improving the adhesion and producing a superior sample transport medium. In tests TrueTube EPS has demonstrated the lowest adsorption and desorption of moisture and organo-sulfur compounds.

    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 G4.1 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.

  • Technical Specifications for Cardinal Stick Tubing +


    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.
  • Literature +

  • Gas and Process Sample Transport Systems for Analyzer Applications +


    Tube Selection for Analyzer Sample Systems
    Selecting the right process tube for use in analyzer sample transport systems requires critical considerations of process and application conditions. There are a wide variety of metallic and non-metallic tube types available: welded and seamless 304 and 316 series stainless steel, other metallurgies used are Monel®, Hastelloy®, Inconnel®, Incoloy®, zirconium, Super-Duplex, titanium, and even copper. Common non-metallic tube materials are Teflon® (PFA, PFE, and PTFE fluoropolymer), polyethylene and Halar (ECTFE). Some bundles may also contain coaxial tubing (tube-in-tube) or unheated tubes for calibration gas and blowback lines.

    O’Brien Analytical also provide a wide variety of in-house services including electropolishing and chemical passivation as well as thermocouple cleaning and cleaning for oxygen service. We also furnish fused silica lined process tubes.

    Improper tube selection may lead to a failed analyzer systems caused by adsorption, contaminants in the tube, corrosion stress cracking or gas permeation. Restricted sample flow, long sample lag times, and kinking are also problems often related to tube selection.

    Tube Selection for Analyzer Sample Systems
    Selecting the right process tube for use in analyzer sample transport systems requires critical considerations of process and application conditions. There are a wide variety of metallic and non-metallic tube types available: welded and seamless 304 and 316 series stainless steel, other metallurgies used are Monel®, Hastelloy®, Inconnel®, Incoloy®, zirconium, Super-Duplex, titanium, and even copper. Common non-metallic tube materials are Teflon® (PFA, PFE, and PTFE fluoropolymer), polyethylene and Halar (ECTFE). Some bundles may also contain coaxial tubing (tube-in-tube) or unheated tubes for calibration gas and blowback lines.

    O’Brien Analytical also provide a wide variety of in-house services including electropolishing and chemical passivation as well as thermocouple cleaning and cleaning for oxygen service. We also furnish fused silica lined process tubes. (see tubing product classifications)

    Improper tube selection may lead to a failed analyzer systems caused by adsorption, contaminants in the tube, corrosion stress cracking or gas permeation. Restricted sample flow, long sample lag times, and kinking are also problems often related to tube selection.

    Selecting Tube Material
    Consider the porosity, corrosion, and adsorption as well as the size and metallurgy (or composition) of the tubing.

    Porosity
    Fluoropolymer tubes are common for many analyzer applications particularly stack gas measurement. For all of its positive characteristics fluoropolymer is “porous” and has a limited working pressure, which deteriorates rapidly as temperature increases. Consider using only thick wall (0.062” / 1.5mm) tubing.

    If the porosity and / or pressure rating is not acceptable then consider using electropolished or fused silica lined stainless steel tube. While resistant to most chemicals fused silica (consider it the same as glass) has limited resistance to acids so caution should be exercised.

    Corrosion
    When you check for corrosion resistance it is imperative that you design for failure. Just because the process stream does not contain acids under normal conditions you need to determine the component concentrations and byproducts if an upset occurs. The creation of acids is common in stack gas applications when inadequate heating allows water vapor to condense and combine with sulfur or nitrogen compounds.

    Adsorption
    When utilizing stainless steel tubing this phenomenon will exhibit itself in the measurement of trace amounts of component (especially moisture and sulfur compounds, H2S and SO2.) The structure of commercial stainless steel tubing is such that compounds may be caught up in the “crevices” and not reach the analyzer. Once the tube is saturated the levels will equalize relative to the process as long as the process composition, temperature and pressure remain constant. Any change in composition, temperature or pressure may cause compounds to be adsorbed more by the tube or release from the tube surface and “spike” the sample to the analyzer. As a result adsorption / desorption creates inconsistent and unpredictable results. This is sometimes referred to as the “memory effect”. This problem can often be solved by the use of electropolished or fused silica lined tubing.

    TUBE GENERAL USES CHARACTERISTICS
    Commercial 316L Seamless SS Standard instrument tubing. Free Fe will react with most acids. Improved surface roughness
    Limitations:
    Limited by chemical reactivity and oxygen levels
    Subject to stress corrosion cracking.
    High Ra values of internal surface contribute to adsorption / desorption problems.
    Advantages:
    Inexpensive and readily available.
    Commercial 316L Welded SS Standard low pressure / temperature instrument tubing.
    Free iron will react with most acids. Weld containments may contribute to reduced corrosion protection compared to seamless tubing.
    Improved surface roughness
    Limitations:
    Limited by chemical reactivity and oxygen levels
    Subject to stress corrosion cracking.
    Pressure rating less than seamless products.
    May be more susceptible to corrosion than seamless products.
    Advantages:
    Inexpensive and readily available.
    Fluoropolymer (Teflon®) Low pressure sample and chemical lines where 316 SS is not acceptable. Used for applications requiring cleanliness. Surface Roughness: NA
    Limitations:
    Limited by chemical reactivity and oxygen levels.
    Temperature and pressure limits vary by variety of fluoropolymer.
    Very permeable. Used for manufacture of permeable membranes.
    Advantages:
    Excellent chemical resistance.
    Flexible.
    TrueTube CP Applications requiring additional cleanliness or corrosion resistance compared to commercial SS tube. An O’Brien Analytical Product
    Chemically polished 316L SS seamless tubing.
    Improved surface roughness
    Limitations:
    Limited by chemical reactivity and oxygen levels.
    Advantages:
    Enhanced Cr/Fe and CrO/FeO ratios improve chemical resistance.
    Improved adsorption / desorption characteristics compared to commercial tubing.
    TrueTube EP Critical sample systems where adsorption / desorption is a problem. An O’Brien Analytical Product
    Electropolished and chemically treated 316L SS seamless tubing.
    Improved surface roughness
    Limitations:
    Limited by chemical reactivity and oxygen levels.
    Advantages:
    Cr/Fe ratio better than 1.5:1 and CrO/FeO ratio better than 3:1 improve chemical resistance.
    Improved adsorption / desorption characteristics compared to commercial tubing.
    TrueTube FS Moderately acid samples and sulfur. An O’Brien Analytical Product
    A secondary fused silica coating applied to chemically polished 316L SS tubing.
    Surface Roughness: NA
    Limitations:
    Very poor resistance to bases.
    Reacts adversely with fluorides.
    Advantages:
    Has improved chemical resistance over substrate alone.
    Can be used at higher temperatures than polymer coatings.
    Covalently bonded matrix which reduces surface tension.
    Has found wide acceptance for transporting sulfur samples.
  • Test Data +


    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