Tubing materials

The accuracy of the calculated solution is highly depending of realistic values for conductivity and permeability of the tube material. While the conductivity can be found in the literature for most materials, the right permeability is harder to determine. In the RFEC technique the exciter current and thus the exciter field strength is often to high to assume a... 

Doyle, J. L., Wood, G. R., and Bondurant, P. D. Using Laser-Based Profilometry to Locate and Measure Corrosion Fatigue Cracking in Boiler Tubes, Materials Evaluation, D The American Society of Nondestructive Testing, Inc., Vol. 51, No. 5, pp. 556-560 (1993). 

Flexible Tube. The simplicity of design and the absence of seals and valves make the flexible tube or peristaltic pump a good choice for low capacity and low pressure appHcations in the pharmaceutical industry or wherever shear-sensitive or moderately abrasive fluids are pumped. Because of the continuous flexing of the tube, the tube material of constmction presents a challenge regarding life cycle. For the same reason, pressures are kept relatively low. 

It is assumed that process conditions and physical properties are known and the following are known or specified tube outside diameter D, tube geometrical arrangement (unit cell), shell inside diameter D shell outer tube limit baffle cut 4, baffle spacing and number of sealing strips N,. The effective tube length between tube sheets L may be either specified or calculated after the heat-transfer coefficient has been determined. If additional specific information (e.g., tube-baffle clearance) is available, the exact values (instead of estimates) of certain parameters may be used in the calculation with some improvement in accuracy. To complete the rating, it is necessary to know also the tube material and wall thickness or inside diameter. 

In order to ehminate galvanic action the outer tube material may be stripped from the tube ends and replaced with ferrules of the inner tube material. When the end of a tube with a ferrule is expanded or welded to a tube sheet, the tube-side fluid can contact only the inner tube material, while the outer material is exposed to the shell-side fluid. 

Tube material includes any that can be formed into a coil, but usually copper, copper alloys, and stainless steel are most common. The casing or shell material can be cast iron, cast steel, cast bronze, fabri-catea steel, stainless, and other high-alloy materials. Units are available with pressure vessel code conformance. 

Bonilla [Trans. Am. Inst. Chem. Eng., 41, 529 (1945)] developed a simplified method for distributing the heating surface in a multiple-effect evaporator to achieve minimum cost. If the cost of the evaporator per unit area of heating surface is constant throughout, then minimum cost and area will be achieved if the ratio of area to temperature difference A/AT is the same for all effects. If the cost per unit area z varies, as when different tube materials or evaporator types are used, then zA/AT should be the same for all effec ts. 

Rigid Porous Media These are available in sheets or plates and tubes. Materials used include sintered stainless steel and other metals, graphite, aluminum oxide, silica, porcelain, and some plastics—a gamut that allows a wide range of chemical and temperature resistance. Most applications are for clarification. 

The vapor vent valves are connected to the tank vapor control valve, and ultimately to the carbon canister by tubing that is resistant to swelling in the presence of fuel vapors. The tubing material must also have a low HC permeation rate, so that the evaporative emissions are not increased due to release of HC molecules. The tank vapor control valve connects the carbon canister to two fuel tank vapor sources the vapor vent valve lines and a refueling vent tube. 

Mechanically bonded tubes may be obtained by mechanically stressing the fin material and/or the tube material to hold the two elements in pressure contact with one another. So called tension wound fins are formed by winding the fin material under tension in a helical manner along the length of the tube. 

Individual fins may be preformed and inserted over the tube, after which the mechanical bond may be obtained by either shrink fitting the fins onto the tube or by expanding the tube radially outward to make pressure contact with the fin material. The means to expand the tube may be hydraulic by pressurizing the tube beyond its yield point or it may be of a mechanical nature, in which an oversized ball or rod is pushed through the length of the tube, forcing the tube material outward against the fin. 

Table. Cf is a tube materials selection chart (the common tube nuiten als to use for different kinds of services). Standard tube lengths arc eifiK r 2() ft or 40 ft.

Plain tubes (either as solid wall or duplex) are available in carbon steel, carbon alloy steels, stainless steels, copper, brass and alloys, cupro-nickel, nickel, monel, tantalum, carbon, glass, and other special materials. Usually there is no great problem in selecting an available tube material. However, when its assembly into the tubesheet along with the resulting fabrication problems are considered, the selection of the tube alone is only part of a coordinated design. Plain-tube mechanical data and dimensions are given in Tables 10-3 and 10-4. 

For bends this sharp, the tube wall on the outer circumference of the tube may thin down IV2—2 gage thicknesses, depending on the condition and specific tube material. More generous radii will reduce this thinning. TEMA presents a formula for calculating the minimum wall thickness. 

Tubes - Material irvrpgrViPU GrapVl.4ft No, Shell - Moferiol . ... 

Wolverine has presented evaluations of the cost comparisons for various types of exchangers and tube materials. 

Except for fluid conditions of possible galvanic corrosion, the tins can be any selected material, not necessarily the same as the tube. Some usable tin and/or tube materials are... 

Select design pressure on tube side, tube material, tube size, and gage. 

Campbell points out that in evaluating condenser tube materials a test apparatus is required that will include all the principal hazards likely to be encountered in service and should thus cater for the following conditions impingement, slow moving water, heat transfer and shielded areas. Furthermore, the internal surfaces should not be abraded, as in the jet impingement test, but should be tested in the as-manufactured condition, particularly in view of the deleterious effect of carbon films produced during manufacture (see Sections 1.6 and 4.2). LaQue has pointed out the importance of specimen area in impingement tests... 

Fig. 19.23 Campbell test apparatus for determining the various forms of attack that condenser-tube materials are subjected to in service (after Campbell...

Romero, Matilde F. Pdrez, Orlando Navarro, Alfredo. Phosphate Attack as Caustic Corrosion in High-Pressure Boiler Tubes. Material Performance . NACE International, USA, March 1999. 

Tubing material 300-series HPLC grade steel Maximum working pressure for tubing 70 MPa... 

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