Rubber lining inspection

The production of a rubber lining includes the preparation of the rubber compound followed by processing to form the lining sheet, substrate preparation, lining application, vulcanisation and inspection. All these stages require thorough quality control, especially compound manufacture and sheet preparation, as chemical resistance depends on satisfactory dispersion of the individual ingredients and undetected flaws in the sheet will cause problems in service. 

The following guide should be used while inspecting and spark testing of rubber lined tanks. 

On-line inspection is a form of testing and in this context dimensional measurements are those most often made. Apart from gauges, micrometers and so on, there are various optical, electrical, nuclear and other methods which may have advantages in production circumstances. Descriptions of the use of such techniques can be found in the literature and in manufacturers data sheets. Some fairly recent examples relating to rubber and plastics products are given in references 12 - 16. However, the various techniques will not be reviewed here. 

Pipelines are cleaned and inspected using pigs . Pigs usually have a steel body fitted with rubber cups and brushes or scrapers to remove wax and rust deposits on the pipe wall, as the pig is pumped along the pipe. Sometimes spherical pigs are used for product separation or controlling liquid hold up. In field lines handling untreated crude may have to be insulated to prevent wax formation. 

Piping in transfer lines should be free of loops and pockets. Unloading connections may be flexible hose (typically 50-mm) lined with acid-resistant rubber, crosslinked polyethylene, or a fluorocarbon polymer. These hoses should not have quick disconnects. They should be inspected after every use. A sight glass on the transfer line will let the operator know when transfer is complete. 

There are many types of rubber used in lining vessels and it is most important to know the limitations of the type being used on a particular vessel. The total range of resistance from rubbers is much wider than the individual resistance of any particular type. Maintenance must include regular inspections and repairs as necessary. The smallest defect should be repaired immediately to prevent the spreading of the damage. 

Rubber equipment should be visually inspected and gloves should have an air test done before use. Protective hats and climbing equipment should be worn. Safety lines should be used in emergency rescue situations. Metal or conductive ladders should not be used near energized lines or other electrical equipment. 

Organic linings, e.g., plastics and elastomers (rubbers), are suitable for some locations, can provide low initial cost, and sometimes have surprisingly low annual maintenance costs. However, complete replacement of these materials every 10 to IS years is to be expected and flue gas temperature excursions are always a concern. In addition, routine inspection and... 

Inspect insulating equipment (i.e., blankets, covers, line hoses, gloves, and sleeves made of rubber) for the following ... 

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