1 For all aluminium closed vessels (including water coolers with aluminium fins), the nitrogen seal should be confirmed before cutting the orifice on site and the hydrogen content at the upper orifice should be measured to see if it is within the normal range. Before cutting, the nitrogen seal nut should be gently unscrewed to release the nitrogen seal pressure and air must be kept circulating at the release site. After the nitrogen has been released, dry air should be used to displace any hydrogen that may have been generated. When cutting, the operation of open flames is prohibited and the tube mouth is oriented as far down as possible to prevent chips from entering the interior of the small air separation unit, ensuring that the chip round plate inside the small air separation unit and the chip baffle inside the receiver are removed.
2 Aluminium towers must be cut on the ground and all orifice baffles or headers must be removed and properly sealed before entering the cold box.
3 has been cut bored plate or head of the tower, if can not be continuous tower docking, should be clean aluminum chip after the original bored plate or head reset, if necessary, with the orifice spot welding, and tape paper wrapped firmly, and then sealed with clean plastic cloth protection, to prevent debris, grease dirt, moisture, etc. into. It is strictly forbidden to leave the mouths of the tubes open to allow humid air and rainwater to enter.
4 After the aluminium container is in place, the uppermost orifice should be kept open (rainproof measures should be taken, the rest of the orifice should be closed) and the bottom should be filled with a small amount of dry air at regular intervals so that the gas at the top of the container is fully replaced to avoid possible accumulation of trace hydrogen gas at the top of the container or in the pipes.
5 Before welding the vessel orifice, the vessel should be adequately replaced internally and the hydrogen content at the orifice should be analysed to confirm that there are no problems before welding.
6 When the test pressure of the cold box system as a whole is completed, the corresponding pipe valves and safety valve baffles at the top of each aluminium vessel should be opened in time and replaced by dry air blowing from the bottom. If you need to weld the pipe flanges etc., you must analyse the hydrogen content at the mouth of the pipes and confirm that there are no problems before welding. Until bare cooling, the top of the aluminium vessel should be left open at least one way, and the bottom should be regularly filled with a small amount of dry air so that the gas at the top of the vessel is fully replaced.
DEAR air separation's small air separation units, large air separation units and liquid air separation plants are manufactured with mature and standardised technology to ensure safe operation and maintenance, stability and efficiency.
