Steel cylinders low pressure

Gaseous nitrogen dioxide is a brown, paramagnetic, non-flammable, toxic, strongly oxidizing, coiTosive substance shipped in approved, low-pressure steel cylinders. It is prepared in situ by heating lead nitrate ... 

Surface tension at 90" 16.70 dynes/cm. Shipped as i liquefied gas in low pressure steel cylinders under its own vapor pressure of about 136 pounds per square inch. Contaminants are propane, ethane, carbon dioxide. 

Figures 10-3 through 10-7 provide examples of the various types of corrosion and apply to compressed gas cylinders made of steel. For other than high or low pressure steel cylinders, see CGA C-6.1, CGA C-6.2, CGA C-6.3, CGA C-8, and CGA C-13 [11, 12, 13, 14, 15].

Low pressure steel cylinders. Failure to meet any of the following four general rules is cause for condemning the cylinder ... 

Low pressure steel cylinders. Where denting occurs so that any part of the deformation includes a weld, the maximum allowable dent depth is 0.25 inches (6.4 mm). When denting... 

Low pressure steel cylinders. Bulges in low pressure steel cylinders can be measured as follows ... 

Representative Cylinder Wall Thickness, To use the above criteria, it is necessary to know the minimum allowable wall thickness at manufacture. Table 9-1 provides the minimum allowable wall thickness for a number of common size low pressure steel cylinders. 

Considerations of appearance play a major factor in the evaluation of dents. Dents can be tolerated when the cylinder wall is not deformed excessively or abruptly. Dents are of concern where the metal deformation is sharp and confined, or, in the case of low pressure steel cylinders, where it is near a weld. Where metal deformation is not sharp, dents of larger magnitude can be tolerated. 

Low Pressure Steel Cylinders. For low pressure steel cylinders, depth limits are such that ... 

The footring and headring and/or neckring on cylinders may lose their intended functions, which are, respectively (1) to cause the cylinder to remain stable and upright and (2) to protect the valve. Rings must be examined for distortion, for looseness, and for condition of threads and, in the case of low pressure steel cylinders, for failure of welds. Appearances may often warrant removal of the cylinder from service. 

In addition to external inspection, low pressure steel cylinders not exempted from hydrostatic retesting and high pressure cylinders must be inspected internally at least every time the cylinder is periodically retested. 

Example 17.11 A flow of 25,000 m /d of treated water is to be disinfected using chlorine in pressurized steel cylinders. The raw water comes from a reservoir where the water from the watershed has a very low alkalinity. With this low raw-water alkalinity, coupled with the use of alum in the coagulation process, the alkalinity of the treated water when it finally arrives at the chlorination tank is practically zero. Calculate the amount of alkalinity required to neutralize the acid produced during the addition of the chlorine gas. 

TC/DOT 4B, 4BA, and 4BW. These are welded or brazed low-carbon steel cylinders with a volumetric capacity of not over 1000 lb (454 kg) of water, made for a maximum service pressure of 500 psig (3450 kPa). 

The following sections summarize the inspection procedures provided in CGA C-6, Standards for Visual Inspection of Steel Compressed Gas Cylinders [10]. Except where noted, the focus pertains to low pressure and high pressure steel cylinders. While many of the same considerations apply to the inspection of aluminum cylinders and cylinders made of materials other than steel, the respective CGA technical publications should be consulted for specific procedures and defect limitations concerning such cylinders. See CGA C-6.1, C-6.2, andC-6.3 [11, 12, 13]. 

General criteria for low pressure and high pressure steel cylinders are given in the following paragraphs. For greater detail, see the referenced CGA publications. 

Interior corrosion is best evaluated by a hydrostatic test combined with careful visual inspection. Ultrasonic thickness-measuring and flaw-detection devices may be used to evaluate specific conditions. Corrosion limits for both low and high pressure steel cylinders were dis-... 

The most common material used in cylinder construction is cast iron for the larger, low-pressure cylinders and steel for the smaller, high pressure cylinders. In some cases, nodular or ductile iron can be used in lieu of cast iron. For hydrocarbon service, steel is most desirable, although not universally available. 

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