Upper tower and main condenser assembly in small air separation unit
Assembly using wind, electric tools to cut away the test pressure blind, or head with aircraft methods to clean up the welding area; according to the chart processing bevel, the site preparation scaffolding must be safe and solid, welders should be in accordance with the provisions of T4734-22 qualified by examination, group positioning welding and formal welding are used for two people at the same time double-sided cross-welding when the cover layer can be used for single welding. Group pair positioning welding must ensure that the plate side of the wrong side of the amount and tower vertical, verticality on the tower tolerance welding environment. Positioning welding and formal welding shall not be in the rain, snow or relative humidity above the environment, if the temperature is below 5 ℃ when the cold box should be heated measures. Welding preheating: when the upper tower and the main cold wall thickness is not greater than 6, should be preheated to a 100 ℃, when the wall thickness is greater than or equal to a 100 ℃ should be preheated
Welding order: according to the positioning of the tower body after welding may cause verticality and tower plate level change to determine (that is, the use of post-welding deformation to further positive verticality and level).
Welding inspection: after welding by the appearance of the inspection shall be made to the weld should be in line with the "non-destructive inspection of pressure equipment radiation testing" level of the provisions of the standard. Weld rework; if the weld fails the ray inspection and needs to be reworked, mechanical methods should be used to remove defects and rework should not exceed two times. More than two repairs should be approved by the chief engineer of the installation unit.
After the installation of the cold box pipe ring seam welding qualified. Immediately fixed with the upper tower bracket. At the same time of fixing, again correct the verticality, its tolerance is 1.
Sections of the ex-factory gauge packing on the tower and argon tower site assembly welding requirements should be carried out in accordance with the corresponding product drawing provisions.
Heat exchanger according to the large group after lifting into position. Perpendicularity tolerance 1 and in the total height range
Dirty nitrogen liquefier, oxygen liquefier, etc. need to be installed with its bracket before lifting up.
Automatic box and pipe welding before the need to set up temporary bracket.
The verticality tolerance of other tower equipment is not more than 0.5.
Cold box of other containers in the installation should be noted - each container pipe mouth in the receiver before, should be clean white cloth tie mouth to avoid grease dirt into.
In the cold box and in the condensing evaporator welding in small air separation unit, flame or arc is strictly prohibited to hit the surface of the container and pipeline, the container, valve, pipeline and the corresponding bracket in the cold box in small air separation unit. The inner surface of the cold box and the foundation surface should not be stained with grease after installation, otherwise they should be de-oiled.
