Maintenance of pressure vessels during decommissioning

01 Keep the pressure vessel dry and clean to prevent atmospheric corrosion. Scientific practice has proved that dry air, carbon steel and other iron alloys generally do not produce corrosion, only in the case of moisture (relative humidity of more than 60%), and the metal surface with dust, dirt or old corrosion products exist, corrosion began to take place. Therefore, in order to reduce the corrosion of the atmosphere on the external surface of the decommissioned pressure vessel, the surface of the vessel should be kept clean, often scattered on the surface of the pressure vessel dust, ash and other dirt scrubbed clean, and keep the pressure vessel and the surrounding environment dry.

02 Paint the outer wall of the pressure vessel to prevent atmospheric corrosion, also pay attention to the insulation layer under and pressure vessel support at the anti-corrosion, etc.

03 The pressure gauge should be kept clean, the glass on the dial must be bright and clear so that the pressure reading indicated by the pointer in the gauge is clear and easy to see. Found that the pressure table (including taking the pressure tube) should be dealt with in a timely manner when there is a fault, the pressure table of the indicated value of doubt, should be promptly calibrated with the standard table, incorrect when it should be replaced. Pressure gauge to be regularly calibrated, calibration cycle of not less than 6 months, after the calibration of the pressure gauge should be affixed with a certificate of conformity and sealed.

04 Pressure table has one of the following conditions, should stop using and replace: limited stop nail pressure table, in the absence of pressure, the pointer can not return to the limit stop nail; unlimited stop nail pressure table (limited to the positive pressure table), in the absence of pressure, the value of the pointer from the zero position exceeds the allowable error of the pressure table; dial cover glass rupture or dial scale blurred; seal damage or more than the validity of the calibration period, the table spring tube leakage or pressure table The pointer is loose; the pressure gauge pointer is broken or the casing is corroded seriously and other defects that affect the accurate indication of the pressure gauge.

05 Pressure vessels are usually equipped with the necessary safety devices according to their process characteristics. There are many types of safety devices, which should be reasonably installed and arranged, such as safety valves and pressure gauges. To make the safety device is often in good condition, keep accurate and reliable, sensitive and good, must be in the process of pressure vessel operation to strengthen the maintenance and maintenance of safety devices.

06 Pressure vessel accessories parts must be kept complete, intact. For the connection fasteners incomplete pressure vessel, prohibited to put into operation. Many pressure vessel end caps fly out of major explosive accidents, are caused by end cap flange bolt damage.

07 Pressure vessels due to maintenance, cleaning open end cover, the number of bolts, the operator is often only part of the fastening bolts, the amount of bolts installed in insufficient, poor sealing and often over-tighten the nut, bolt preload is very large, so that after the container pressure flange bolts break, resulting in end cover flying out of the explosion accident. Therefore, for the pressure vessel fastening bolts and other accessories parts, in each take down, should first be cleaned, and then the appearance of inspection, inspection of qualified fastening bolts can be reused.
Source: Pressure Vessel Man
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