Design of Radial Nozzles in Cylindrical Shells for Internal Pressure

1980 ◽  
Vol 102 (1) ◽  
pp. 70-78 ◽  
Author(s):  
W. L. McBride ◽  
W. S. Jacobs
Keyword(s):  
Internal Pressure ◽  
Elastic Stress ◽  
Design Method ◽  
Pressure Vessels ◽  
Strain Gages ◽  
Allowable Stress ◽  
Working Pressure ◽  
Division 1 ◽  
Section Viii ◽  
Empirical Design

A design method is presented that allows a designer to predict the maximum allowable working pressure of an opening reinforcement using an allowable stress basis. Primary application of the method is directed toward large openings as defined by ASME Section VIII, Division 1, paragraph UA-7. Recent hydrotests conducted on several production pressure vessels have demonstrated that existing paragraph UA-7 area replacement rules are inadequate in certain d/D and D/T ranges. The inadequate designs were initially indicated by leakage at a flange located close to the nozzle shell intersection. Later, another vessel hydrotest was terminated because of distortion and high readings from strain gages located at the nozzle-to-shell intersection. The proposed empirical design method produces nozzle reinforcements that should remain in the elastic stress range for internal pressure up to the Code-required hydrotest.

Developing Methodology for Elevated Temperature Design of Section VIII, Division 1 Vessels Considering Load Durations

2008 ◽  
Author(s):  
Charles Becht ◽  
Greg L. Hollinger
Keyword(s):  
Pressure Vessels ◽  
Operating Pressure ◽  
Design Consideration ◽  
Allowable Stress ◽  
Short Term ◽  
Time Duration ◽  
Load Duration ◽  
Division 1 ◽  
Section Viii ◽  
Term Creep

The rules of Section VIII, Division 1 provide an allowable stress for design of pressure vessels that is independent of load duration. In the time dependent regime, where failure by creep rupture is a consideration, the actual life of the vessel depends on a number of things, including the margins provided in the allowable stresses, the margin between design pressure and operating pressure, the margin between design temperature and operating temperature. While material properties for a time duration of 100,000 hours are included as part of the basis in establishing the allowable stress, this is neither an anticipated life nor a design life for the pressure vessel. There are short term conditions for which design based on an allowable stress set based on long term creep properties is unrealistically conservative. This paper provides recommendations for design rules for very short term loads for which creep should not be a design consideration, termed occasional loads herein, and rules for loads for which creep is a design consideration.

A Study of Stresses in Cylindrical Shells Having Tapped Holes Parallel to the Axis of the Cylinder

2016 ◽  
Author(s):  
Dipak K. Chandiramani ◽  
Shyam Gopalakrishnan ◽  
Ameya Mathkar
Keyword(s):  
Cylindrical Shell ◽  
Internal Pressure ◽  
Shell Thickness ◽  
Pressure Vessels ◽  
Inside Surface ◽  
Shell Wall ◽  
Allowable Stresses ◽  
Metal Thickness ◽  
Division 1 ◽  
Section Viii

Clause UG-27 of ASME Section VIII Division 1 [1] provides rules for calculating the thickness of shells under internal pressure. Mandatory Appendix-2 of Code [1] provides rules for design of bolted flanged connections. In certain high pressure and high thickness pressure vessels having a cylindrical shell with bolted cover flange, Manufacturers avoid a separate end flange welded to the shell, as the construction becomes bulky. Instead of the same, Manufacturers provide tapped holes in shell wall parallel to axis of the cylindrical shell. The cover is directly bolted to these tapped holes provided in the shell. This type of construction may be economical as compared to welding a conventional flange to the end of the shell. However this type of construction is not covered in the Code [1]. When such tapped holes are provided in the cylindrical shell, generally the total metal thickness provided at the tapped hole location meets UG-27 requirement of the Code [1]. However due to the tapped holes, the thickness from inside surface of vessel to inside surface of tapped hole is less than the required thickness of UG-27. It is therefore required to analyze the stresses due to these tapped holes in the shell thickness to ensure that Code [1] allowable stresses are not exceeded. The work reported in this paper was undertaken to determine the effect of internal pressure on the stresses in a cylindrical shell having tapped holes parallel to axis of the cylindrical shell.

Very thin torispherical pressure vessel ends under internal pressure: Test procedure and typical results

1981 ◽  
Vol 16 (3) ◽  
pp. 171-186 ◽  
Author(s):  
P Stanley ◽  
T D Campbell
Keyword(s):  
Stainless Steel ◽  
Internal Pressure ◽  
Elastic Stress ◽  
Test Procedure ◽  
Pressure Vessels ◽  
Time Dependent ◽  
Test Installation ◽  
Stress Indices ◽  
Pressure Test ◽  
Strain Data

Very thin cylindrical pressure vessels with torispherical end-closures have been tested under internal pressure until buckles developed in the knuckles of the ends. These were prototype vessels in an austenitic stainless steel. The preparation of the ends and the closed test vessels is outlined, and the instrumentation, test installation, and test procedure are described. Results are given and discussed for three typical ends (diameters 54, 81, and 108in.; thickness to diameter ratios 0.00237, 0.00158, and 0.00119). These include measured thickness and curvature distributions, strain data and the derived elastic stress indices, and pole deflection measurements. Some details of the observed time-dependent plasticity (or ‘cold creep’) are given. Details of two types of buckle that developed eventually in the vessel ends are also reported.

Methods for Design of Explosion Containment Vessels

2008 ◽  
Author(s):  
Yongjun Chen ◽  
Jinyang Zheng ◽  
Guide Deng ◽  
Yuanyuan Ma ◽  
Guoyou Sun
Keyword(s):  
Time Use ◽  
Design Method ◽  
Failure Criteria ◽  
Pressure Vessels ◽  
Design Criterion ◽  
Load Factor ◽  
Multiple Use ◽  
Strain Limit ◽  
Section Viii ◽  
Future Work

Explosion containment vessels (ECVs), which can be generally classified into three categories, i.e., multiple use ECVs and one-time use ECVs, single-layered ECVs and multi-layered ECVs, metallic ECVs and composite ECVs according to the usage, structural form and the bearing unit, respectively, are widely used to completely contain the effects of explosions. There are fundamental differences between statically-loaded pressure vessels and ECVs that operate under extremely fast loading conditions. Conventional pressure design codes, such as ASME Section VIII, EN13445 etc., can not be directly used to design ECVs. So far, a lot of investigations have been conducted to establish design method for ECVs. Several predominant effects involved in the design of ECVs such as scale effect, failure mode and failure criteria are extensively reviewed. For multiple use single-layered metallic ECVs, dynamic load factor method and AWE method are discussed. For multiple use composite ECVs, a minimum strain criteria based on explosion experiments is examined. For one-time use ECVs, a strain limit method proposed by LANL and a maximum strain criteria obtained by Russia are discussed for metallic vessel and composite vessel, respectively. Some improvements and possible future work in developing design criterion for ECVs are recommended as a conclusion.

Guidelines for MACA: The Optimization of Corrosion Allowance

2016 ◽  
Author(s):  
Jaan Taagepera ◽  
Craig Boyak
Keyword(s):  
Plate Thickness ◽  
Service Evaluation ◽  
Pressure Vessels ◽  
Life Extension ◽  
Optimized Design ◽  
Excess Capacity ◽  
Allowable Stress ◽  
Minimum Thickness ◽  
Working Pressure ◽  
Maintenance And Inspection

Excess capacity in the design of a pressure vessel can be recognized in a maximum allowable working pressure (MAWP). This pressure value is the result of the calculations for minimum thickness, in the new condition, being rounded up to the next nominal plate thickness and then working the formulae to establish limiting pressure based on the actual thickness used. Another variable which may be optimized is the design temperature. Raising the design temperature tends to result in a reduced allowable stress. Once a plate thickness has been determined, the necessary allowable stress can be back calculated. From this allowable stress, an optimized design temperature can be determined. Excess capacity can also be recognized in the form of increased corrosion allowance or MACA, the Maximum Allowable Corrosion Allowance. This is particularly helpful in the maintenance and inspection realms where life extension or unexpected thinning can force an unplanned shutdown of the unit, a fitness for service evaluation, or repair once the specified corrosion allowance is exhausted. This paper presents a set of guidelines or rules for establishing a MACA based optimization for the design of new pressure vessels.

The Applicability of the ASME Boiler and Pressure Vessel Code, Section XII, Transport Tanks, for Use in U.S. Federal Maritime Regulations

2010 ◽  
Author(s):  
Allen Selz ◽  
Daniel R. Sharp
Keyword(s):  
Pressure Vessel ◽  
Road Transport ◽  
Pressure Vessels ◽  
Department Of Transportation ◽  
The Road ◽  
Dangerous Goods ◽  
Division 1 ◽  
The Us ◽  
Section Viii ◽  
Marine Applications

Developed at the request of the US Department of Transportation, Section XII-Transport Tanks, of the ASME Boiler and Pressure Vessel Code addresses rules for the construction and continued service of pressure vessels for the transportation of dangerous goods by road, air, rail, or water. The standard is intended to replace most of the vessel design rules and be referenced in the federal hazardous material regulations, Title 49 of the Code of Federal Regulations (CFR). While the majority of the current rules focus on over-the-road transport, there are rules for portable tanks which can be used in marine applications for the transport of liquefied gases, and for ton tanks used for rail and barge shipping of chlorine and other compressed gases. Rules for non-cryogenic portable tanks are currently provided in Section VIII, Division 2, but will be moved into Section XII. These portable tank requirements should also replace the existing references to the outmoded 1989 edition of ASME Section VIII, Division 1 cited in Title 46 of the CFR. Paper published with permission.

A Study of the Conservatism in ASME BPVC Section VIII Division 2 Opening Design for External Pressure

2019 ◽  
Author(s):  
Barry Millet ◽  
Kaveh Ebrahimi ◽  
James Lu ◽  
Kenneth Kirkpatrick ◽  
Bryan Mosher
Keyword(s):  
Finite Element ◽  
Internal Pressure ◽  
Pressure Vessel ◽  
External Pressure ◽  
The Other ◽  
Finite Element Analyses ◽  
Division 1 ◽  
Section Viii ◽  
Allowable Compressive Stress ◽  
Division 2

Abstract In the ASME Boiler and Pressure Vessel Code, nozzle reinforcement rules for nozzles attached to shells under external pressure differ from the rules for internal pressure. ASME BPVC Section I, Section VIII Division 1 and Section VIII Division 2 (Pre-2007 Edition) reinforcement rules for external pressure are less stringent than those for internal pressure. The reinforcement rules for external pressure published since the 2007 Edition of ASME BPVC Section VIII Division 2 are more stringent than those for internal pressure. The previous rule only required reinforcement for external pressure to be one-half of the reinforcement required for internal pressure. In the current BPVC Code the required reinforcement is inversely proportional to the allowable compressive stress for the shell under external pressure. Therefore as the allowable drops, the required reinforcement increases. Understandably, the rules for external pressure differ in these two Divisions, but the amount of required reinforcement can be significantly larger. This paper will examine the possible conservatism in the current Division 2 rules as compared to the other Divisions of the BPVC Code and the EN 13445-3. The paper will review the background of each method and provide finite element analyses of several selected nozzles and geometries.

Evaluation of ASME Pressure Vessel Code Prohibitions on Rod and Bar Stock and Potential Remedies

2014 ◽  
Author(s):  
John J. Aumuller ◽  
Vincent A. Carucci
Keyword(s):  
Pressure Vessels ◽  
Early 20Th Century ◽  
Economic Disadvantage ◽  
User Experiences ◽  
The Public ◽  
Division 1 ◽  
Asme Code ◽  
Billet Material ◽  
Section Viii ◽  
Division 2

The ASME Codes and referenced standards provide industry and the public the necessary rules and guidance for the design, fabrication, inspection and pressure testing of pressure equipment. Codes and standards evolve as the underlying technologies, analytical capabilities, materials and joining methods or experiences of designers improve; sometimes competitive pressures may be a consideration. As an illustration, the design margin for unfired pressure vessels has decreased from 5:1 in the earliest ASME Code edition of the early 20th century to the present day margin of 3.5:1 in Section VIII Division 1. Design by analysis methods allow designers to use a 2.4:1 margin for Section VIII Division 2 pressure vessels. Code prohibitions are meant to prevent unsafe use of materials, design methods or fabrication details. Codes also allow the use of designs that have proven themselves in service in so much as they are consistent with mandatory requirements and prohibitions of the Codes. The Codes advise users that not all aspects of construction activities are addressed and these should not be considered prohibited. Where prohibitions are specified, it may not be readily apparent why these prohibitions are specified. The use of “forged bar stock” is an example where use in pressure vessels and for certain components is prohibited by Codes and standards. This paper examines the possible motive for applying this prohibition and whether there is continued technical merit in this prohibition, as presently defined. A potential reason for relaxing this prohibition is that current manufacturing quality and inspection methods may render a general prohibition overly conservative. A recommendation is made to better define the prohibition using a more measurable approach so that higher quality forged billets may be used for a wider range and size of pressure components. Jurisdictions with a regulatory authority may find that the authority is rigorous and literal in applying Code provisions and prohibitions can be particularly difficult to accept when the underlying engineering principles are opaque. This puts designers and users in these jurisdictions at a technical and economic disadvantage. This paper reviews the possible engineering considerations motivating these Code and standard prohibitions and proposes modifications to allow wider Code use of “high quality” forged billet material to reflect some user experiences.

Sign in / Sign up

Export Citation Format

Share Document