Ati Luleh Sepahan Co
Established in Nov. 2000, Ati Luleh Sepahan Co. started it activity by producing intermixture pipes with PEX-AL-PEX structure and at present is continuing its activities with 11 production lines. Through a plan development project, number of plant production lines will reach to 15 lines with a nominal capacity of 50 million meters of pipe/year. Actually productions of this firm include five. layered pipes of seven sizes from 16mm to 63mm all conforming with the standard ASTM-F1281 and in accordance with such creditable standards as BS and DVGW, produced under supervising of the Research Center of the Department of Housing and Urban Development. Such products are manufactured and supplied to the local and abroad markets.
Raw materials used to produce laminated five layered newpipes include: Aluminum foils of thicknesses of 200 to 700 microns, worth crossing polyethylene or PEX, and special adhesive to be added between internal and external aluminum and polymer layers.
Raw materials in the beginning of entry to the plant are quality controlled in the laboratory. Regarding aluminum foils, after ensuring of correctness of dimensions, and bearing tensile strength test their percentage of length increase at the shear point is measured.
Also for PEX polymer, molten flux index is measured by the MFI device. Measurement of humidity percentage is another test conducted on PEX polymer. Due to sensitivity of polymer to humidity and heat, this test is of considerable importance. Regarding adhesive used between the layers, in addition to MF1 test, another test named PeeL, showing adhesiveness strength of the adhesive is done.
Aluminum foils and adhesives required by the production lines, following confirmation by the quality control unit, are conveyed to the production lines for consumption and PEX polymer is transmitted to the special mixer where, after adding catalyst and such materials called co-process at precise and appropriate weight percentage are fully mixed and homogenized and then conveyed to the production line.
Production lines are controlled via an automatic electronic system. Beginning point of each production line is where aluminum foils are charged. This foil, via propulsion power of the tracer device is gradually opened and conducted to the different sections of the production line.
Aluminum foil gradually passes under rolls of a conducting bench so that while being opened, little by little it changes to a U-shaped section ready for being rolled. Then, aluminum foil, via a pair of rolls or foil rollers is rounded and its rims are overlapped for a few millimeters. Following forming the aluminum pipe, the ultrasonic welding machine rapidly welds the two overlapped rims of the foil and when aluminum is welded, while blowing warm air of constant pressure into the pipe, via the two layered matrix of the internal mould inside the aluminum pipes, adhesive and polymer layers are injected respectively. The three layered pipe for complementary works and forming outer shells enters the two internal layered matrix and there as well, via two external devices, adhesive and polymers are injected to coat the aluminum pipe which is changed to a 5 layered pipe. Regarding high 200 0C temperature of the pipe once produced, it is immediately immersed into a cool water pool. Also, via compressed air the pipe is hundred percent hydrostatically tested. The cooled pipe passes through a laser caliper to control its outside diameter. In the second phase, through assessment of pipe metrage, via the printer machine at each one meter of the pipe are printed all its specifications including shift, hour and date, mark, pipe size, application conditions, technical specifications and finally length of the pipe. The completed pipe, following passing through the traction device is collected in rolls of 50-300 m on the roller. To control internal diameter via a metallic ball with dimensions appropriate to the pipe internal diameter, pressurized air is passed through the pipe so that in the event of any projection or defect the metallic ball is jammed and the defected site is identified. Evidently in case of full sundness of the internal layer, the ball will cross the pipe with no difficulty and will exit the roll form its other end. All produced pipe rolls, through the process, by appropriate sampling. At this department, during the process are controlled by staff of the quality control department, samples will be taken from the pipes being manufactured. The samples will undergo such tests as spring test to observe appropriate adhesion of layers to each other, controlling diameters and thicknesses and their relations. Following control during the process, produced pipe will be sent to the steam unit. All the steaming phase which is considered as an important section of the process of manufacturing PEX-AL-PEX the pipes will be exposed to steam for a period of about 17 to 22 hours so that the polymer reticulation chemical reaction inside and outside the pipe is conducted and polymer structure becomes reticulated. Following termination of steaming of the pipes synchronously with sending pipe batches to the department of final control, their samples will be sent to the laboratory for testing. In the laboratory, standard ASTM-F 1281 tests will be performed on samples of the final product.
The first measurement test will be assessment of gel percentage of the pipes to indicate suitable level of polymer crosslink or reticulation. To do so, samples of steamed pipes are placed inside the boiling xylen solution for a period of 8 hours and then the difference between the initial and secondary weights of the samples is measured.
The following test is called the impeller test specially conducted on pipe sizes over 32 mm which indicates adhesion power of adhesive between the pipe layers.
Measurement of the pipe tensile strength is another test conducted on a 2.5 cm ring of the pipe. At this test, the pipe should bear a force of at least 2100N to 2600N and the tearing should not occur at the seam point. In the final stage, standard pressure tests are conducted on the pipe. The first pressure test is the one conducted on the tear point or burst test. This test is conducted at two stages once at room temperature and once again at 82 0C. During this test, the pipe sample is compressed up to the point of burst. Then figures obtained at the pipe burst point are compared with the standards. During another compression test called maturity test, the pipe after 2 hours being placed in an environment of
82 0C for temperature equalization, will be subjected to a constant pressure of 27 bar and should bear such conditions for at least 10 hours without the least modifications occurring.
At the final control department, following obtaining all confirmation of the tests, all pipe batches will once again undergo adhesion test and after controlling their situation of print and package of rolls, while registering specifications of all rolls in the final control form, the green label of the quality control department will be attached to the beginning of the roll and in this way the roll will receive the storing permit.
In the store unit, the p
ipes via special devices are foam bounded and packaged. Also specifications of each roll is attached on it via a special label so that the packed pipe, can exit the plant according to the client order.