Vessel linings inspected

Vessel linings should be inspected within the first year of operation. The subsequent frequency of inspection is determined on the basis of the findings of the first inspection. The nature of the fluid being handled also plays a part in the decision. 

Mechanical. Manholes, isolation facilities, vents, drains, cleanout/ steamout facilities, and access all acceptable for entry and maintenance correct interface for agitators, etc. correct shape and finish for internal lining system (if any) correct configuration and types of clip for refractory and insulation (for all vessels requiring them, but especially for heat-treated vessels) provision for in-line inspection (tell-tales, underfloor drainage) when needed transport... 

The suggested method is appropriately implemented at the practice. The cost and working hours of unit measurement of it is less than of any alternative method of destructive test and with respect to the authenticity inspection of Stress-Deformation the given method is inferior only to destructive testing. The method was successfully implemented while evaluation of service life of main pipe-lines sections and pressure vessels as well. Data of method and instrument are used as official data equally with ultrasonic, radiation, magnetic particles methods, adding them by the previously non available information about " fatigue " metalwork structure. 

Inspection techniques are available for specific coating and lining systems. Proper bonding to substrate is necessary to avoid blistering and disbonding in case of a vacuum being created in the vessel. 

The availability of probes that can be welded to the outer walls of piping or process vessels providing on-line thickness measurement is an interesting development which would seem to bridge the technologies of corrosion monitoring and inspection". 

Inspection and testing requirements are covered in detail. Most vessels are required to be hydrostatic-tested (generally with water) at 1.3 times the maximum allowable working pressure. Some enameled (glass-lined) vessels are permitted to be hydrostatic-tested at lower pressures. Pneumatic tests are permitted and are carried to at least IV4 times the maximum allowable working pressure, and there is provision for proof testing when the strength of the vessel or any of its parts cannot be computed with satisfactory assurance of accuracy. Pneumatic or proof tests are rarely conducted. 

With a newly installed precautionary blind in the overflow line, the hidden blind in the vent line, and no additional overpressure devices, the tank was destined to fail. As liquid was pumped into the vessel the inerts had no place to go and the tank was pressurized to destruction. To the best of everyone s knowledge and the evidence, this hard-to-detect blind may have been inserted over a year prior to the incident for a previous internal inspection of the acid tank. Obviously the mechanic(s) who removed the other blinds a year or so before and on this occasion did not notice this one. 

An open steel basket-frame type construction can be used to overcome some of the problems noted with the use of lead lined wood vessels. Sheet lead straps are wrapped around the horizontal and vertical structural steel supports. The lead sheets are formed and weld attached to the noted straps. This type of construction is advantageous because it may be thoroughly inspected while in service. Faults are apparent and repairs easily made. 

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