Design Of Baffles [12

Baffles are frequently used in pressure vessels, either vertical or horizontal, to divide the interior volume into different compartments. These compartments may be used to segregate liquids or provide overflow weirs for the separation of liquids. Baffles may be stiffened or unstiffened. When welded across the entire cross section of the vessel, they must be checked that they are not unduly restricting the diametral expansion of the vessel. If the unrestrained radial expansion of the vessel...

References

ASCE 7-95, Minimum Design Loads for Buildings and Other Structures, American Society of Civil Engineers. 2. Recommended Practice 11, Wind and Earthquake Design Standards, Chevron Corp., San Francisco, CA, March 1985. 3. Uniform Building Code, 1997 Edition, International Conference of Building Officials, Whittier, CA, 1997. 4. Bednar, H. H., Pressure Vessel Design Handbook, Van Nostrand Reinhold Co., 1981, Section 5.1. 5. Brownell, L. E., and Young, E. H., Process Equipment Design, John Wiley...

Calculating Angle a

ASME Code 1 , This paragraph requires a discontinuity analysis of the cone-shell juncture. 3. No reinforcing rings or added reinforcement is required at the intersections of cones and cylinders, providing a knuckle radius meeting ASME Code requirements is used. The minimum knuckle radius for the large end is not less than the greater of 3t or 0.12(R + t). The knuckle radius of the small end (flare) has no minimum. (See Reference 1, Figure UG-36 ). 4. Toriconical transitions are advisable to...

Fieldfabricated Spheres

A sphere is the most efficient pressure vessel because it offers the maximum volume for the least surface area and the required thickness of a sphere is one-half the thickness of a cylinder of the same diameter. The stresses in a sphere are equal in each of the major axes, ignoring the effects of supports. In terms of weight, the proportions are similar. When compared with a cylindrical vessel, for a given volume, a sphere would weigh approximately only half as much. However, spheres are more...

Design Of Base Details For Vertical Vessels

Ab required area of anchor bolts, in.2 Bp allowable bearing pressure, psi (see Table 3-35) bp bearing stress, psi C compressive load on concrete, lb d diameter of bolt circle, in. db diameter of hole in base plate of compression plate or ring, in. Flt longitudinal tension load, lb in. Flc longitudinal compression load, lb in. Fb allowable bending stress, psi Fc allowable compressive stress, concrete, psi (see Table 3-35) Fs allowable tension stress, anchor bolts, psi (see Table 3-33) Fy minimum...

Support Structures

There are various methods that are used in the support structures of pressure vessels, as outlined below. a. Cross braced (pinned and unpinned) One of the most common methods of supporting vertical pressure vessels is by means of a rolled cylindrical or conical shell called a skirt. The skirt can be either lap-, fillet-, or butt-welded directly to the vessel. This method of support is attractive from the designer's standpoint because it minimizes the local stresses at the point of attachment,...

Design Of Pipe Coils For Heat Transfer [1018

This procedure is specifically for helical pipe coils in vessels and tanks. Other designs are shown for illustrative purposes only. Helical coils are generally used where large areas for rapid heating or cooling are required. Heating coils are generally placed low in the tank cooling coils are placed high or uniformly distributed through the vertical height. Here are some advantages of helical pipe coils. 1. Lower cost than a separate outside heat exchanger. .'3. Fluids circulate at higher...

12

Cross-bracing the legs will conveniently reduce bending in legs due to overturning moments (wind and equipment) normally associated with unbraced legs. The lateral bracing of the legs must be sized to take lateral loads induced in the frame that would otherwise cause the legs to bend. 2. Legs may be made from angles, pipes, channels, beam 3. Legs longer than about 7 ft should be cross-braced. 4. Check to see if the cross-bracing interferes with piping from bottom head. 5. Shell stresses at the...

215216

Reinforcement at small end with internal pressure, 213-214 Cone lifting lugs, 416-419 Cones, formula, 16 Corrosion fatigue, 5 stress, 5 Creep deformation, 5 Critical force, 85 Critical length, 85 Critical load, 85 Critical stress, 85 Critical wind velocity, 244, 246, 249 See also Cone-cvlinder intersections calculating proportions, 92 Cylindrical shells. 11 buckling of thin-walled, 85-89 external pressure design for, 20 formulas, 15, 88 Cylindrical shells, stress in bending moment, 278, 280,...

2

Both ASME Code, Section VIII, Division 2 and ASME Code, Section III, utilize the maximum shear stress criterion. This theory closely approximates experimental results and is also easy to use. This theory also applies to triaxial states of stress. In a triaxial stress state, this theory predicts that yielding will occur whenever one-half the algebraic difference between the maximum and minimum stress is equal to one-half the yield stress. Where al > a2 > the maximum shear stress is (cti ct3)...

Wind Design Per Asce [1

Projected area, sq ft force coefficient, shape factor 0.7 to 0.9 vessel effective diameter, from Table 3-4 fundamental natural frequency, 1 T, cycles per second, Hz design wind force, lb 3.5 for vessels gust effect factor, Cat A and B 0.8, Cat C and D 0.85 gust response factor for flexible vessels height of vessel, ft importance factor, see Table 3-1 the intensity of turbulence at height z velocity pressure exposure coefficient from Table 3-3a, dimensionless topographic factor, use 1.0 unless...

01849

'Values of 1.43 log1oR r + 0.11 (r R)2 2Values of 1.43 log,0R r +0.334+ 0.06(r R)2 Values of 1.365 (3n + 2ni + 3) 6Values of 50 (3n + 2n2 + 12.5) Reprinted by permission of AISI, Committee of Steel Plate Producers and Steel Plate Fabricators Association, Inc. from Steel Plate Engineering Data, Volume 2 'Values of 1.43 log1oR r + 0.11 (r R)2 2Values of 1.43 log,0R r +0.334+ 0.06(r R)2 Values of 1.365 (3n + 2ni + 3) 6Values of 50 (3n + 2n2 + 12.5) Reprinted by permission of AISI, Committee of...

Transportation And Erection Of Pressure Vessels 365

Procedure 7-1 Transportation of Pressure Vessels, 365 Procedure 7-2 Erection of Pressure Vessels, 387 Procedure 7-3 Lifting Attachments and Terminology, 391 Procedure 7-4 Lifting Loads and Forces, 400 Procedure 7-5 Design of Tail Beams, Lugs, and Base Ring Details, 406 Procedure 7-6 Design of Top Head and Cone Lifting Lugs, 416 Procedure 7-7 Design of Flange Lugs, 420 Procedure 7-8 Design of Trunnions, 431 Procedure 7-9 Local Loads in Shell Due to Erection Forces, 434 Procedure 7-10...

1

F dead load-)-live load, psf fb bending stress, beam, psi fa axial stress, psi fx.v.r bolt loads, lb F total load on bracket, lb A load area, ft2 A' cross-sectional area of kneebrace, in.2 Mi moment at shell, ft-lb M2 moment at bolts, ft-lb or in.-lb C distance to C.G. of area, ft K end connection coefficient, use 1.0 r' radius of gyration, in. P axial load on kneebrace, lb Z section modulus of beam, in.3

General Design

Procedure 2-1 General Vessel Formulas, 15 Procedure 2-2 External Pressure Design, 19 Procedure 2-3 Calculate MAP, MAWP, and Test Pressures, 28 Procedure 2-4 Stresses in Heads Due to Internal Pressure, 30 Procedure 2-5 Design of Intermediate Heads, 31 Procedure 2-6 Design of Toriconical Transitions, 33 Procedure 2-7 Design of Flanges, 37 Procedure 2-8 Design of Spherically Dished Covers, 57 Procedure 2-9 Design of Blind Flanges with Openings, 58 Procedure 2-10 Bolt Torque Required lor Sealing...

R

The ASME Code does not give specific procedures for designing vessels for wind. However, Para. UG-22, Loadings, does list wind as one of the loadings that must be considered. In addition, local, state, or other governmental jurisdictions will require some form of analysis to account for wind loadings. Client specifications and standards also frequently require consideration of wind. There are two main, nationally recognized standards that are most frequently used for wind design. They are 1....

015

Membrane force due to Pr. (Extracts from BS 5500 1985 are reproduced by permission of British Standards Institution, 2 Park Street London, W1A 2BS, England. Complete copies can be obtained from national standards bodies.) Figure 5-26. Bending moment due to Pr. (Extracts from BS 5500 1985 are reproduced by permission of the British Standards Institution, 2 Park Figure 5-26. Bending moment due to Pr. (Extracts from BS 5500 1985 are reproduced by permission of the British Standards...

Buckling Of Thinwalled Cylindrical Shells

This procedure is to determine the maximum allowable stress for tubular members that are subject to axial compression loadings. Tubular members may be a pressure vessel, a pipe, a silo, a stack, or any axially loaded cylinder of any kind. In addition, axial-loaded cylinders may be subjected to other load cases simultaneously. Other load cases include bending and internal or external pressure. Axial loads can also result when a vertical vessel, stack, or silo is transported and erected from the...

Vessel Nomenclature

Fabrication Pressure Vessel Tray Support

Drums and miscellaneous vessels Any of the above listed vessels can be field fabricated however, normally only those vessels that are too large to transport in one piece are field fabricated. Although it is significantly more expensive to field fabricate a vessel, the total installed cost may be cheaper than a shop fab that is erected in a single piece due to the cost of transportation and erection. There are always portions of field fab vessels that are shop fabricated. These can be as small...

Transportation Of Pressure Vessels

The transportation of a pressure vessel by ship, barge, road, or rail will subject the vessel to one-time-only stresses that can bend or permanently deform the vessel if it is not adequately supported or tied down in the right locations. The shipping forces must be accounted for to ensure that the vessel arrives at its destination without damage. It is very frustrating for all the parties involved to have a load damaged in transit and to have to return it to the factory for repairs. The cost...

13

S., Design of Radial Nozzles in Cylindrical Shells for Internal Pressure, Journal of Pressure Vessel Technology, Vol. 2, February 1980. ASME Boiler and Pressure Vessel Code, Section VIII, Division 1, American Society of Mechanical Engineers, 1995. Catudal, F. W., and Schneider, R. W., Stresses in Pressure Vessels with Circumferential Ring Stiffeners, Welding Journal Research Supplement, 1957. Wolosewick, F. E., Supports for Vertical Pressure Vessels, Part III,...

Ws

If W LDf < 20, a vibration analysis must be performed. If 20 < W LD2 < 25, a vibration analysis should be performed. If VY' LD* > 25, a vibration analysis need not be performed. If W5 LD 2 < 0.75, the vessel is unstable. If 0.75 < W5 LD 2 < 0.95, the vessel is probably unstable. If WS LDf > 0.95, the structure is stable. Step 3 If ft < 0.95, check critical wind velocity, Vc. If Vt. > V, then instability is expected. Step 4 Calculate dynamic deflection, A, . (2.43)(109)L5Vi2...

Membrane Stress Analysis

Pressure vessels commonly have the form of spheres, cylinders, cones, ellipsoids, tori, or composites of these. When the thickness is small in comparison with other dimensions (Rm t > 10), vessels are referred to as membranes and the associated stresses resulting from the contained pressure are called membrane stresses. These membrane stresses are average tension or compression stresses. They are assumed to be uniform across the vessel wall and act tangentially to its surface. The membrane or...

Thick Walled Pressure Vessels

As discussed previously, the equations used for design of thin-walled vessels are inadequate for design or prediction of failure of thick-walled vessels where Rin t < 10. There are many types of vessels in the thick-walled vessel category as outlined in the following, but for purposes of discussion here only the monobloc type will be discussed. Design of thick-wall vessels or cylinders is beyond the scope of this book, but it is hoped that through the following discussion some insight will be...

Design Of Vessel Supports 109

Procedure 3-1 Wind Design per ASCE, 112 Procedure 3-2 Wind Design per UBC-97, 118 Procedure 3-3 Seismic Design for Vessels, 120 Procedure 3-4 Seismic Design Vessel on Unbraced Legs, 125 Procedure 3-5 Seismic Design Vessel on Braced Legs, 132 Procedure 3-6 Seismic Design Vessel on Rings, 140 Procedure 3-7 Seismic Design Vessel on Lugs 1, 145 Procedure 3-8 Seismic Design Vessel on Lugs 2, 151 Procedure 3-9 Seismic Design Vessel on Skirt, 157 Procedure 3-10 Design of Horizontal Vessel on Saddles,...

Nozzle Reinforcement

The following are only guidelines based on Section VIII, Division 1 of the ASME Code 1 . This is not an attempt to cover every possibility nor is it to become a substitute for a. No reinforcement other than that inherent in the construction is required for nozzles 1, Section UG-36(c) (3) 3-in. pipe size and smaller in vessel walls 3 8-in. and less. 2-in. pipe size and smaller in vessel walls greater than 3 8 in. b. Normal reinforcement methods apply to 1, Section UG-36(b) (1) Vessels 60-in....

Design Of Bins And Elevated Tanks [39

Bins Civil Engineering

The definition of a bulk storage container can be quite subjective. The terms bunkers, hoppers, and bins are commonly used. This procedure is written specifically for cylindrical containers of liquid or bulk material with or without small internal pressures. There is no set of standards that primarily applies to bins and since they are rarely designed for pressures greater than 15 psi, they do not require code stamps. They can, however, be designed, constructed, and inspected in accordance with...

Minimum Design Metal Temperature Mdmt

Ri ratio of thickness required at MDMT to the corroded thickness Ro ratio of the actual stress to the allowable stress tMT thickness required of the part at MDMT, in. tDT thickness required of the part at design temperature, in. t thickness of the part, new, in (exclusive of thinning allowance for heads and undertolerance for pipe) tt. thickness of the part, corroded, in. C.a. corrosion allowance, in. E joint efficiency Smt allowable stress at MDMT, psi S)yr allowable stress at design...

Pressure Vesels In Civil Engineering

Ladder and platform (L& P) estimating, 105 Large-diameter nozzle openings, 203-207 I D ratio, 89-90 Legs, erection of vessels with, 394 Legs, seismic design for braced calculations, 135-136 dimensional data, 133 flow chart for, 138 legs and cross-bracing, sizes for, 137 load diagrams, 134 loads, summary of, 136 notation, 132 Legs, seismic design for unbraced calculations, 127-129 Legs, seismic design for unbraced (Continued) dimensional data, 126 leg configurations, 126 leg sizing chart, 131...

Erection Of Pressure Vessels

Pressure Vessel Vertical Tower

The designer of pressure vessels and similar equipment will ultimately become involved in the movement, transportation, and erection of that equipment. The degree of that involvement will vary due to the separation of duties and responsibilities of the parties concerned. It is prudent, however, for the designer to plan for the eventuality of these events and to integrate these activities into the original design. If this planning is done properlv, there is seldom a problem when the equipment...

Seismic Designvessel On Skirt [1 2

T period of vibration, sec S i code allowable stress, tension, psi H overall height of vessel from bottom of base plate, ft hx height from base to center of section or e.g. of a concentrated load, ft h, height from base to plane under consideration, ft of, fi, y coefficients from Table 3-20 for given plane based on hx H Wx total weight of section, kips W weight of concentrated load or mass, kips W total weight of vessel, operating, kips W), total weight of vessel above the plane under...

Vibration Of Tall Towers And Stacks [1727

Tall cylindrical stacks and towers may be susceptible to wind-induced oscillations as a result of vortex shedding. This phenomenon, often referred to as dynamic instability, has resulted in severe oscillations, excessive deflections, structural damage, and even failure. Once it has been determined that a vessel is dynamically unstable, either the vessel must be redesigned to withstand the effects of wind-induced oscillations or external spoilers must be added to ensure that vortex shedding does...

Type 1 Butt Weld Uw

Communicating Chamber Pressure Vessel

For shackles with safe loads greater than the maximum shown, use Crosby-Laughlln The Crosby Group, Div. of American Hoist amp Derrick Co, Tulsa, OK 74101 . Skookum Skookum Co., Inc., Portland, OR 97203 , or equal with an ultimate strength at least 5 times the safe working load. For shackles with safe loads greater than the maximum shown, use Crosby-Laughlln The Crosby Group, Div. of American Hoist amp Derrick Co, Tulsa, OK 74101 . Skookum Skookum Co., Inc., Portland, OR 97203 , or equal with an...

Allowable Buckling Stress In Cylindrical Shells [1420

A metal cross-sectional area, in.2 B ASME Code allowable stress, psi C end connection coefficient, use 1.0 for simply supported and 2.0 for cantilevered Cc. max allowable slenderness ration per AWYVA D-100 D OD of cylinder, in. E modulus of elasticity, psi e tolerance for peaking, in. FS factor of safety Fv minimum specified yield strength, psi F , allowable longitudinal compressive stress, psi 1 moment in inertia, in.4 Lc length at which critical stress is achieved, in. 1 tolerance for...

Seismic Designvessel On Unbraced Legs [47

Vertical Pressure Vessels Design

A cross-sectional area, leg, in.2 V base shear, lb W operating weight, lb n number of legs Cv vertical seismic factor Ch - horizontal seismic factor y static deflection, in. Fv vertical seismic force, lb F , horizontal seismic factor, see Procedure 3-3 F l allowable axial stress, psi F , allowable bending stress, psi F, - seismic force applied at top of vessel, lb F'. Euler stress divided by safety factor, psi fi maximum eccentric load, lb V horizontal load on leg, lb Fn maximum axial load, lb...

External Pressure Chart

If a vessel is designed for less than 15 psi, and the external pressure condition is not going to be stamped on the nameplate, the vessel does not have to be designed for the external pressure condition. Figure 2-1 b. External pressure cones 22 112 lt a lt 60 . For Case B, L . L For Cases A, C, D, E Figure 2-1e. Geometrie chart for components under external or compressive loadings for all materials . Reprinted by permission from the ASME Code. Section VIII, Div. 1. Figure 2-1e. Geometrie chart...

21

Welding Journal Research Supplement, December 1955, pp. 608-617. Bijlaard, P. P., Stresses from Radial Loads and External Moments in Cylindrical Pressure Vessels. Welding Journal Research Supplement, December 1954, pp. 615-623. Megyesy, E. F., Pressure Vessel Handbook, 3rd Edition, Pressure Vessel Handbook Publishing Co., 1975, pp. 72-85. Zick, L. P., Stresses in Large Horizontal Cylindrical Pressure Vessels on Two Saddle Supports, Welding Research Journal Supplement, September 1951. Moody, G....

Discontinuity Stresses

Vessel sections of different thickness, material, diameter, and change in directions would all have different displacements if allowed to expand freely. However, since they are connected in a continuous structure, they must deflect and rotate together. The stresses in the respective parts at or near the juncture are called discontinuity stresses. Discontinuity stresses are necessary to satisfy compatibility of deformation in the region. They are local in extent but can be of very high...