Titanium tubes

Pase, G. K andJ. O Donnell, Use Titanium Tubes to Greate Higher Gapacity Gorrosion Resistant Exchangers, Hydro. Proc., Oct. (1995)... 

Copper-base alloys will corrode in aerated conditions. It is, therefore, sometimes appropriate to consider cathodic protection. It becomes particularly relevant when the flow rates are high or when the design of an item causes the copper to be an anode in a galvanic cell (e.g. a copper alloy tube plate in a titanium-tubed heat exchanger). Corrosion can be controlled by polarisation to approximately — 0-6V (vs. CU/CUSO4) and may be achieved using soft iron sacrificial anodes. 

Titanium tubes with diameter 22 mm and thickness 2.6 mm were subjected to cyclic non uniform heating for a long time. The temperature difference on the tube length of 15 cm is about 200°C. The tube edges were fixed that led to creation of thermo-mechanical tensions. After about 15000 cycles of loading, fatigue cracks were formed at the point with minimum temperature. 

Figure 4. Scheme of probe position with respect to the crack in titanium tube. 

Cu—(Ti, Zr)—Ni eutectic clad strip, RS foil titanium/zirconium-ba titanium tubing, aircraft... 

Total suspended solids (TSS) were collected from 15 liters of each sample with a Sorvall SS-3 centrifuge, equipped with a "Szent-Gyorgyi and Blum" KSB continuous flow system. Titanium tubes were used to minimize contamination. The system was operated at 10,000 rpm with a flow rate of 125 mL/min. The solids were quantitatively transferred to 50 mL, polycarbonate centrifuge tubes and excess water was removed by centrifugation. Solids were frozen and later extracted in these centrifuge tubes. Additional material to determine total suspended solids (TSS) was collected from 8 liters of water by use of the continuous flow system. Finally the solids were transferred to porcelain crucibles and dried at 110° C to a constant weight. 

Fig. 8 Design features of a wide bore probe head for HPNMR (400 MHz) measurements. 1 O-ring 2 probe jacket 3 thermal insulation 4 polyvinyl chloride 5 O-ring 6 O-ring 7 semi-rigid coaxial cable 8 connection to thermostat 9 titanium tube 10 lid 11 screw 12 capacitor 13 capacitor holder 14 aluminium tube 15 upper plug 16 sample tube 17 saddle coil 18 -Macor 19 TiA16V4 vessel 20 lower plug 21 lower pressure screw 22 capacitor 23 coaxial cable and 24 capacitor holder.

Iodine-125 sources. Iodine-125 is widely used for permanent implants in radiotherapy. The encapsulation consists of a 0.05 mm thick titanium tube welded at both ends to form a cylindrical capsule of dimensions 4.5 x 0.8 mm. Iodine-125 decays exclusively by electron capture to an excited state of Technetium-125, which then emits a 35.5 keV photon. Characteristic x-rays in the range of 27 to 35 keV also are produced due to the electron capture and internal conversion processes. 

The choice of material of construction will influence the extent of possible corrosion and may affect the retention of other deposits, for instance corrosion resistant titanium tubes have been known to foul more rapidly than some stainless steel alloys under similar conditions. It is unlikely in large cooling water systems, e.g. power station condensers, that treatment of the heat exchange surfaces will be considered as a feature for the reduction of fouling, due to the relatively high costs involved including initial cost and maintenance. 

The original saltwater condenser tube made of admiralty brass was found to be susceptible to erosion-corrosion at tube ends. Aluminum brass containing 2% aluminum was more resistant to erosion in saltwater. Inhibition with arsenic is necessary to prevent dezincification as in the case of admiralty brass. The stronger naval brass is selected as the tube material when admiralty brass mbes are used in condensers. Cast brass or bronze alloys for valves and fittings are usually Cu-Sn-Zn compositions, plus lead for machinability. Aluminum bronzes are often used as tube sheet and channel material for exchangers with admiralty brass or titanium tubes exposed to cooling water. 

Closed Rankine eyele ammonia working fluid shell-and-tube HXs with titanium tubes 0.01905 m OD, 0.01765 m ID 4 10-MWe (net) modules Nominal operating eharacteristics... 

Titanium tubing can be used successfully for seawater-cooled heat exchangers [29], where its resistance to pitting and corrosion-erosion make it a useful material. 

Indirect Contact. Direct contact was more popular in the past, when none of the common construction metals was resistant to chlorine. Typical materials of construction were thermosets (such as a phenolic resin reinforced with asbestos) for vessels and stoneware or glass for piping. This situation changed with improvements in fiber-reinforced plastic fabrication and the commercial advent of titanium. The indirect-contact approach has now become a standard. The typical chlorine cooler today is a single-pass vertical shell-and-tube exchanger with titanium tubes and tube sheets and a carbon steel shell (or perhaps FRF in smaller units). Construction of tube sheets may be of solid titanium, or they may be clad or explosion-bonded with titanium. The inlet channel to the primary cooler also may be of titanium the other channels usually are of FRR... 

Fig. 5.11 Cutaway view of the integrated working-counter electrode 1 platinum wire, 2 glass tube, 3 titanium tube, 4 cable. Dimensions are not in scale. Reprinted with permission from Ref. [63]. Copyright 2011 Springer...

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