Drawn tubing

Fig. 2. Friction factors for cylindrical pipe where line A represents drawn tubing line B, commercial steel C, galvanised iron and lines D, E, and F,...

Drawn tubing (brass, lead, glass, and the like) 0.00152... 

The relative roughness is expressed as E D, where E = the surface roughness and D = the internal pipe diameter. Typical values of E D are 0.0015 for drawn tubing, 0.046 for commercial steel and 0.12 for asphalted cast iron. 

Thus, if we were to use the same pipe material (commercial steel) for the model as in the field, we would also have to use the same diameter (48 in.). This is obviously not practical, but a smaller diameter for the model would obviously require a much smoother material in the lab (because Dm -C Df requires em stainless steel, all of which have equivalent roughness values of the order of 0.00006 in. (see Table 6-1). 

A 35°API distillate at 60°F is to be pumped a distance of 2000 ft through a 4 in. sch 40 horizontal pipeline at a flow rate of 500 gpm. What power must the pump deliver to the fluid if the pipeline is made of (a) drawn tubing (b) commercial steel (c) galvanized iron (d) PVC plastic ... 

Diameter (actual of drawn tubing, nominal of standard-weight pipe)... 

Percent roughness For value of/see curve Drawn tubing, brass, tin, lead, glass Clean steel, wrought iron Clean, galvanized Best cast iron Average cast iron Heavy riveted, spiral riveted ... 

The above figures refer to the best quality machine-drawn tubing and rod. Special glasses are often made in relatively small quantities the tubing will then be hand drawn and the dimensional tolerances will be greater. 

The accuracy of the dimensions of machine-drawn tubing is inadequate for such applications as high quality graduated glassware, syringe barrels, interchangeable manometers and many electronic devices which must have metal parts accurately located with respect to the glass-tube envelope. 

To meet such needs precision bore tubing is available, such tubing is made from machine-drawn tubing of normal dimensional standards, but selected for freedom from airlines and stone. 

Both tantalum and niobium are available in foil, sheet, and deep-drawn tubing prepared from both welded and seamless stock. Tubing with a wall thickness of from 10-30 mil (0.25-0.76 mm) is most useful. Seamless tantalum tubing sells in quantity for about 75/m in 6-9-m diameter sizes, whereas an equal amount (volume) of niobium tubing costs only about 20% as much. The materials now available have been electron-beam melted under vacuum, a process which gives a substantial decrease in impurities through volatilization of most of the O, N, H, and C (as CO). Principal impurities in Ta are thus the heavy metals (e.g., 0.01-0.05% each of Wand Nb), and guaranteed purities are >99.85% total. Niobium runs 99.7-99.8% total and contains principally small amounts of W and Ta. 

Commercially drawn tubing with 10-20 mil (0.25-0.51 mm) wall thickness is the easiest to use for small containers, although less expensive items as well as those of more diverse shapes can be fabricated from sheet stock with considerably more skill and a greater investment in time.8,10... 

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