Table 2.
Description of the cylinder requalification process
| Stages | Process | Description |
|---|---|---|
| 1ª | Cylinder arrival | Arrival of the cylinder, together with the service order |
| 2ª | Storage | The cylinder is stored section outside the company |
| 3ª | External inspection | The cylinder manufacturing data, corrosion, cracks are verified |
| 4ª | Deflation | The cylinder is degased (gas removal process) and for this purpose products used vary according to the type of product stored in each cylinder. The cylinder must arrive at the company empty with caustic soda or lime so that it does not have any type of residue inside, but in most cases this does not occur, and the contractor must perform this process. In addition, at this stage, the removal of chlorine odor from the inside of the cylinder is also guaranteed. In cases of excess chlorine inside the cylinder, it is returned to the contractor |
| 5ª | Depressurization | Process in which pressure is removed from the cylinder |
| 6ª | Valve removal | Process in which the valve is removed using a wrench |
| 7ª | Blasting | The cylinder is inserted in an isolated cabin and, using steel shot, all its paint is removed. The process is only completed after removing all the ink from the cylinder. After completion, the employee, through a sieve, separates the paint and the waste from the steel shot in order to reuse the steel shot |
| 8ª | Verification of mass, thickness and weighing | Verification of Mass, Thickness and Weighing—an ultrasound is used in this process. Each cylinder must meet defined standards for mass, thickness and weighing |
| 9ª | Hydrostatic test | The cylinder is filled with water, then a pressure is applied to the cylinder to measure its expansion, which should not exceed 10% of the total; if the expansion is greater than recommended, the cylinder is condemned. The water that is removed from the cylinder is weighed on a scale, as the weighing indicates the volume that the cylinder has expanded, or is measured with a burette—a cylindrical laboratory instrument that has a rigorous graduated scale |
| 10ª | Washing | Then, the cylinder is washed with water, at a temperature of 90° C to remove residues and clean inside; the water vapor itself assists in its internal drying |
| 11ª | Internal drying | Drying must be carried out by circulating completely dry air inside the cylinder, in order to ensure that at the end of the operation there is no moisture inside the cylinder. This procedure is performed with high pressure blowing or aspiration |
| 12ª | Internal look | It is verified with the naked eye, with the aid of a twelve-volt lamp, if there are any substances inside the cylinder (water, dirt or other product) |
| 13ª | Valving process | Process performed manually to install the valve on the cylinder; this valve may be new or not |
| 14ª | Typing | The month and the year in which it was restocked are identified on the cylinder; this service is performed manually |
| 15ª | Painting | Painting is done manually, using compressed air and paint in a booth. This painting can be prime and normal, prime, or just normal |
| 16ª | Drying | Drying is carried out naturally, making its time vary according to the ambient temperature and the type of paint used. The cylinder is hung on an overhead conveyor or placed on the floor until it is completely dry, in addition, the handling of some types of paint can only be done after twenty-four hours. To find out if the thickness of the paint is adequate, an equipment is used for the exact measurement of the thickness |
| 17ª | Final inspection | Quality control of the service provided |
| 18ª | Report issuance | It consists of a grouping of all the data related to the tested cylinder |
| 19ª | Delivery | The means of transport for the delivery of the cylinder varies according to the initial negotiation with the customer |
Source: Own elaboration