Tool & Manufacturing, Inc.Argonne Engineering Professionals

Seminar SeriesSeptember 30, 2009

Argonne National LaboratoryArgonne, IL

Presentation of Case StudyManufacture of a Helium/Hydrogen Heat Exchanger

to the ASME Code

presented by: Mike Seely, PHD.Meyer Tool & Mfg., Inc.

Oak Lawn, IL

Tool & Manufacturing, Inc.

Meyer Tool & Manufacturing, Inc.

Oak Lawn, IL USASpecialists in

Cryogenic, Vacuum and

Pressure Technologies

Tool & Manufacturing, Inc.Specialists in Getting it Right

Our components are installed in the world’s most powerful laser,most powerful particle accelerator, most powerful neutron source,at the South Pole and in other harsh and demanding environments.

All these components are installed with no surprises and workingwithout fault. Our experience and knowledge is what has made thishappen in the past and can make it happen for your project.

With over 240 vessels built and delivered in the last three years,with a value exceeding 3 million dollars, Meyer Tool has theengineering and manufacturing resources to give you a surprisefree experience.

Tool & Manufacturing, Inc.Quick Facts

• Founded: In 1969.

• Location: Oak Lawn, IL USA

• Employees: 35

• Business Type: Contract Manufacturer

• Products: Custom Components and Assemblies for Science and Industry.

• Customers:

USA Department of Energy National Laboratories;

Industrial Gas Liquefaction System Providers;

Vacuum System Original Equipment manufacturers in thin film coating,ddsolar, crystal growth, etc., Medical Equipment, and more…..

Tool & Manufacturing, Inc.A sampling of what we do.

GMR Coating Vessel Laser System Chamber MOCVD Vessel

Aluminum “Hog outs” Anodized Aluminum Vessels Welded Aluminum Vessels

Tool & Manufacturing, Inc.A sampling of what we do.

Water Jacketed CG Vessel UHV Chambers Expert Welding

Precision Machining Inspection & Test Dedicated Cleaning Area

Tool & Manufacturing, Inc.

Case StudyManufacture of a Helium/Hydrogen Heat Exchanger

to the ASME Code

Tool & Manufacturing, Inc.

We started with this.

Tool & Manufacturing, Inc.

And ended up with this.

Tool & Manufacturing, Inc.

What is the ASME Boiler and Pressure Vessel Code?

According to the American Society of Mechanical Engineers(ASME) Statement of Policy:“The ASME Boiler and Pressure Vessel Code provides rules forthe construction of boilers, pressure vessels, and nuclearcomponents. This includes requirements for material design,fabrication, examination, inspection and stamping.”

Tool & Manufacturing, Inc.

The ASME Boiler and Pressure Vessel Code consists of twelveSections. Section VIII contains the Rules for Construction ofPressure Vessels. Section VIII is further divided into threeDivisions. Division 1 treats Vessels designed by rules and does notrequire a detailed evaluation of all stresses. Division 2 providesalternative rules for Vessel design and requires a much moredetailed evaluation of stresses. Division 3 concerns alternate rulesfor construction of High Pressure Vessels (maximum allowableworking pressure above 10,000 psig). The majority of pressurevessels are designed and built to the requirements of Division 1.

Tool & Manufacturing, Inc.

Section VIII Division 1 is a rules based not a design based Code,this means where a mandatory requirement or prohibition existswithin the Code, it must be followed by the designer or fabricator(i.e. Rules based). However where such guidance does not exist,engineering judgment consistent with the Division’s designphilosophy may be used. This is worth stressing: a perfectly validanalysis may lead to a different result than a Division designformula or fabrication detail, however the Code requirement mustbe followed.

Tool & Manufacturing, Inc.

In this case study we are going to look at the design of acryogenic shell and tube heat exchanger. The original designwas a first iteration by a person new to the Code. We willexplore how the design changed when Meyer Tool becameresponsible for the design and manufacture.

Tool & Manufacturing, Inc.

What were we building?

Shell and Tube Counter Flow Heat Exchanger

This heat exchanger enables testing and operation of acryogenic target at 20K and is an integral part of theQWeak Physics Experiment to be conducted atJefferson Laboratory’s Hall C.

Meyer Tool built the heat exchanger in a period ofabout 6 weeks in May and June of 2009.

Tool & Manufacturing, Inc.Liquid Hydrogen Target

He 15KSupply

He ReturnFin TubeHeatExchanger

Pump

Aluminum Cell

electron beam

entrancewindow

exitwindow

Tool & Manufacturing, Inc.Requirements

Shell and Tube Counter Flow Heat Exchanger

Designed, manufactured and Stamped to the ASME SectionVIII U Stamped Pressure Vessel

Design Pressure: 300PSIG/ Full external vacuum

Design Temperature: Max: 100F / MDMT: -459F

Material of Construction: Stainless Steel

Physical Envelope: 10.75” OD Shell; 34.3” OAL; Multi-passInternal copper tube coil.

Tube Side Fluid: Helium 15K / 15 atm

Shell Side Fluid: Hydrogen 20 K

Tool & Manufacturing, Inc.

Physical Components Code Part?

Coil Mandrel Assembly (Coil Supports) No

Copper coil and stainless steel inlet Originally yes, afterand outlet tubes. redesign no.

Shell Yes

End Closures YesSupport Brackets Yes

Tool & Manufacturing, Inc.

The original construction prints showed three copper coilsmounted on a cylindrical mandrel. The mandrel and someother miscellaneous components supported the coils withinthe shell of the exchanger. In both the original and modifieddesign these structural components were not welded to theASME Code Vessel nor did they impose an significant loadson the vessel.

The coils were interconnected in a cross flow arrangement,necessitating three inlets and three outlets for the heliumthrough the shell of the pressure vessel.

These inlets and outlets were stainless steel tubes brazed tothe coils. In the original design the tubes were welded directlyto the shell.

Tool & Manufacturing, Inc.Interior Copper fin tube coil.

Tool & Manufacturing, Inc.

Interior Copper fin tube coil installed in stainless steel shell.

Tool & Manufacturing, Inc.

The original pressure vessel itself consisted of a shellfabricated from a 10” SCH5S Pipe, two elliptical end closuresshown as machined from round bar, one each shell inlet andoutlet consisting of a 3” OD x .065” w tubes welded to the endclosures and a 4.63” OD Conflat Flange, the six stainless steelTube 0.5” OD x .035” w coil inlets and outlets each with twoexternal support brackets.

Tool & Manufacturing, Inc.Original design drawing.

Tool & Manufacturing, Inc.

The first step was to review the original design and determineif it met the Code Rules for design and construction. Besidesthe drawing package the customer had provided a set of CodeCalculations.

Tool & Manufacturing, Inc.

From the basic design rules found in Part UG of Section VIII(UG-27 Thickness of Shells Under Internal Pressure, UG-28Thickness of Shells and Tubes Under External Pressure, UG-32 Formed Heads, and Sections, Pressure on Concave Side)the design appeared to be in compliance. However a deeperreview identified a number of issues that only a close anddetailed reading of Section VIII (or experience) would identify.

Tool & Manufacturing, Inc.

ASME Section VIII paragraph UW-2 (b)(4) requires all CategoryD welds (nozzle to shell or head welds) to be full penetrationwhen the Minimum Design Metal Temperature is below -320F.Therefore the welds shown in the original design on drawings67503-00108 between the End Closure and 3” OD tube anddrawing 67503-00107 between the six inlet/outlet tubes andthe shell were not in compliance.

Tool & Manufacturing, Inc.

ASME Section VIII paragraph UW-2 (b) (3) requires allCategory C welds (nozzle to flange welds) to be fullpenetration when Charpy Impact Testing is required perSection UHA. The welds shown on drawing 67503-00108between the 3” OD Tube and Conflat Flange are not incompliance.

Tool & Manufacturing, Inc.

Section VIII paragraph UG-45 imposes rules for the minimumwall thickness of nozzle necks. These rules supercede thedesign rules of UG-27 and UG-28 when sizing cylindricalnozzle necks. The wording of UG-45 can be confusing the firsttime you read it. The application of these rules can vary forthe particular case. In this design it identified that neither the3” OD tube nor the 0.5” OD tube nozzles had sufficient wallthickness to meet the paragraph requirement.

Tool & Manufacturing, Inc.

UG-45 Nozzle Neck ThicknessThe minimum thickness of nozzle necks shall be the larger of (a) or (b) below. Shear stresses …UG-45(a) The minimum wall thickness of a nozzle neck or other connection shall not be less than the thicknesscomputed from the applicable loadings in UG-22 plus the thickness added for allowances for corrosion andthreading, as applicable, on the connection.UG-45(b) Additionally, the minimum thickness of a nozzle neck shall not be less than the smaller of the nozzlewall thickness as determined in (b)(1), (b)(2) or b(3) below, and the wall thickness determined by (b)(4) below:UG-45(b)(1) for vessels under internal pressure only, the thickness (plus corrosion allowance) required forpressure (assuming E=1.0) for the shell or head at the location where the location where the nozzle neck or otherconnection attaches to the vessel but in no case less than the minimum thickness specified in UG-16(b);UG-45(b)(2); for vessels under external pressure only, the thickness (plus corrosion allowance) obtained by usingthe external design pressure as an equivalent internal design pressure (assuming E=1.0) in the formula for theshell or head at the location where the nozzle neck or other connection attaches to the vessel…UG-45(b)(3) for vessels designed for both internal and external pressure, the greater of the thicknessesdetermined by (b)(1) or (b)(2) above;UG-45(b)(4) the minimum thickness* of standard wall pipe plus the thickness added for corrosion allowance onthe connection; for nozzles larger than the largest pipe size included in ASME B36.10M, the wall thickness of thatlargest pipe size plus the thickness added for corrosion allowance on that connection.

*The minimum thickness for all materials is that wall thickness listed in Table 2 of ASME B36.10M, less 12-1/2 %.For diameters other than those listed as standard in the Table, this shall be based upon the next larger pipe size.

The Code Section

Tool & Manufacturing, Inc.

The original drawing 67503-00105 End Closures showsfabrication of these heads through machining. SA-479 is thematerial selection and is a specification for round bar. Roundbar is not normally permitted for nozzles or heads of this size.However our investigation showed that Code Case 2155would allow it. Code Case 2155 would require additional non-destructive examination on the material, including twotransverse tensile tests, ultrasonic examination and penetrantexamination. Based on how round bar is manufactured, therestood a good chance the material would fail the tensile tests.

Tool & Manufacturing, Inc.Original End Closure Design

Tool & Manufacturing, Inc.

The End Closures could be made from SA-240 plate stockmaterial. However Figure UW-13.3 requires that therequirements of Appendix 20 be met if the head were to bemachined from plate. The Appendix requirements are similarto those of Code Case 2155.

A forge material SA-182 could also be used for thisrequirements. UW-13 (f) (1) would still require a single tensiontest.

We suggested and ultimately used a redesign of the head thatavoided these issues.

Tool & Manufacturing, Inc.

The calculations for the vessel shell and the detail drawing67503-00110 selected a 10” SCH5S (10.75” OD x .134” wall) tomeet the requirements. The minimum design metaltemperature of -459F, below the UHA-51 -320F requirement forimpact testing of materials and production weld samples, ledus to choose seamless pipe for this application. Theavailability of 10”SCH5S Seamless pipe caused SCH10S to besubstituted.

Tool & Manufacturing, Inc.

Because the vessel minimum design metal temperature is below -320F and the vessel isconstructed of stainless steel, we must navigate the requirements of Part UHA. Part UHAdiscusses High Alloy Steels; for Cryogenic Pressure Vessels this means austenitic stainlesssteels, typically 304/304L or 316/316L. Of special interest to Cryogenic Pressure Vesselsusers and fabricators is paragraph UHA-51 pertaining to Impact Test Requirements. Asummary of requirements follows for austenitic stainless steels.

Regardless of minimum design metal temperatures (MDMT) impact tests are NOT requiredwhen the maximum obtainable test specimen is less than 0.099 inches in thickness.

For MDMT above –320F (-196C) impact tests are NOT required.

For MDMT below –320F (-196C) impact tests are REQUIRED of all raw material, weldprocedure qualifications for both the weld and heat affected zone for each type of weldprocess, and production weld test specimens (weld and heat affected zone) for each type ofweld process.

Explanation of UHA-51

Tool & Manufacturing, Inc.

Impact tests may be Charpy Tests performed at –320F (-196C) only if Type 316L weldfiller metal is used (and measured to have a Ferrite Number no greater than 5).Otherwise testing using ASTM E 1820 JIC method at the MDMT must be used.

(As an aside we are not aware of any commercial firms capable of performing the E1820tests at -459F.)

UHA-51(g) exempts the impact test requirements above due to low stress. Wherevessels that have a coincident ratio of design stress in tension to allowable stress of lessthan 0.35, impact test of materials and weld procedures and production welds is NOTrequired.

The ultimate design of this vessel was such that we avoidedhaving to perform Impact Testing through use of the UHA-51(g) exemption on a portion of the components.

Explanation of UHA-51

Tool & Manufacturing, Inc.

Redesign of the End Closures:

We discussed with the customer why the selected theelliptical End Closure design. Driving the choice was a desireto smoothly channel the flow of two phase hydrogen throughthe inlet and outlet of the shell.

After some back and forth discussion the ultimate designeliminated the material testing issues and the nozzles weldissues while being a more economical manufacturingsolution.

Tool & Manufacturing, Inc.Final End Closure Design

Tool & Manufacturing, Inc.

The final End Closure design consisted of a 1.50” thick 304SSSA240 plate with the knife-edge and bolt pattern of a 4.63” ODConflat Flange machined in its outer face. An aluminumdiverter was bolted to the inner face of the End Closure toaddress the customers desire for channeling the Hydrogenflow.

This design eliminated all issues related to the shellinlet/outlet nozzle sizing and welding, material issues relatedto the machined elliptical end closures and was simpler tomachine.

Tool & Manufacturing, Inc.

The original design of the Tube Side inlets and outletsconsisted of 0.5” OD x .065” w tube brazed to the copper coilsand were welded directly to the vessel shell at their exitpoints. Code requirements for wall thickness and fullpenetration welds at the shell precluded the use of thisdesign. Instead we utilized a common cryogenic vesseldesign detail. The “nozzles” welded to the shell wereconstructed of 1” OD round bar with a pilot hole. The roundbar was welded with full penetration welds to the shell, thepilot holes were then drilled out to accept the 0.5” OD tubesfrom the copper coils. The 0.5” OD tubes now not consideredpart of the pressure vessel, could be welded with a moreappropriate sized fillet weld to the round bar nozzles.

Tool & Manufacturing, Inc.Inlet/Outlet Nozzle

Tool & Manufacturing, Inc.Final Design

Tool & Manufacturing, Inc.Non-Destructive Test Requirements

1. Charpy impact testing of base metals and samples of productionwelds using Charpy Impact Tested Weld Procedure Specification.

2. Liquid penetrant testing of End Closure weld prep. Edges per UG-93(4) for flat plates grater than 0.5” thick used to form corner joints and ofthe exposed prep area after welding.

3. Pneumatic testing of the vessel per UG-100.

4. Since we chose to pneumatic test, liquid penetrant testing of allnozzle welds and an structural welds greater than 0.25” in size per UW-50.

Tool & Manufacturing, Inc.

Summary of Changes

1. Vessel Shell changed from welded to seamless pipe toaddress UHA-51 Impact Testing requirements.

2. End Plates material and configuration changed to addressNDE requirements, nozzle thickness requirements, and fullpenetration weld requirements.

3. Coil inlet and outlet nozzle configuration changed toaddress nozzle thickness requirements and full penetrationweld requirements.

4. NDE added: Charpy Impact Testing, Liquid PenetrantTesting, Hydrotest changed to Pneumatic Test.

Tool & Manufacturing, Inc.Finished Helium/Hydrogen Heat Exchanger

Tool & Manufacturing, Inc.Interior Subassembly

Tool & Manufacturing, Inc.Interior Subassembly

Tool & Manufacturing, Inc.Assembly of Coil into Shell

Tool & Manufacturing, Inc.Interior Copper to Stainless Tube Detail

Tool & Manufacturing, Inc.Interior Copper to Stainless Tube Detail

Tool & Manufacturing, Inc.Exterior Stainless Tube Detail

Tool & Manufacturing, Inc.Assembly prior to End Closures

Tool & Manufacturing, Inc.Immersion Cold Shock after completion of welding

Tool & Manufacturing, Inc.Immersion Cold Shock after completion of welding

Tool & Manufacturing, Inc.Completed Helium/Hydrogen Heat Exchanger

Tool & Manufacturing, Inc. Questions?

Contact Ed Bonnema

or Mike Seely

at Meyer Tool

708-425-9080

sales@mtm-inc.com