Cabycal, experts in surface treatment and coating, has developed and installed a 5.5-stage double tunnel for the factory of a leading manufacturer of household appliances. The manufacturer has undertaken a series of improvements in one of its production plants, including the replacement of an old spray pretreatment tunnel for metal parts by a new one with nearly 2,000 nozzles.

In addition to the mechanical assembly of the new machine, the installation was completed with the digital integration of the tunnel with the existing installation and the upgrade of the electrical installation, control panel and automation.

This new double tunnel is capable of enabling only one of its lines and recording a large number of parameters (pressure in the water circuits, motor temperature, vibration in the hydraulic pumps), in order to optimize water and electricity consumption and generate the lowest possible environmental impact. According to estimates, with the new equipment, the company will reduce its electricity consumption by around 80%, which represents an economic saving of more than 130,0001 euros per year.

This energy saving is due to the detailed study of different factors developed by Cabycal’s electrical engineering and automation department to optimize the multinational’s production process. Among the factors studied were the reduction of installed power, the use of frequency inverters in all motors, the elimination of 90% of reactive power and the operation of the new pumps at working pressure demand with integrated PID function.

The factor that has drastically reduced the electrical consumption of the new treatment tunnel has been the reduction in electrical power. The new treatment tunnel has an installed electrical power of 72.6 kW compared to 329.8 kW in the old tunnel.

Another factor taken into account was the use of variable frequency drives on all pumps and fans in the new treatment tunnel. Although this energy saving is less significant than the reduction in installed power, it is also important. By using frequency inverters (see regenerative thermal oxidation), energy savings are achieved by improving the efficiency of the pump or fan it manages. Reactive energy is eliminated by 90% and the optimization of pump consumption increases, since only the necessary power is used to reach the working levels demanded in each treatment process.

On the other hand, in addition to energy savings, there are other factors that variable frequency drives bring to the production process:


    • Eliminates water hammer and vibrations in the pipeline, which increases the useful life of the installed mechanical elements and reduces maintenance work. Increases the useful life of the motors, since the start-up peaks generated by the motors are eliminated.


    • They maintain a constant pressure in the pipeline since the system incorporates pressure sensors and the frequency variators regulate their speed by means of a PID function (proportional, integral and derivative) taking as a reference the pressure demand required by the multinational company.


1 Estimated calculation based on 16-hour workdays, 5 days a week and taking Iberdrola’s fixed rate as a reference.