Have you ever wondered how energy-intensive your company’s production choices are? The need for energy savings in coating systems is an issue that can no longer be ignored, especially as it relates to:
– The environmental need to waste as few resources as possible
It is from such reasoning that we started to design and supply, for a major international company, a new powder coating system designed to meet the dual need of having a painting system with a high production rate but with an eye on energy saving.
The system was born with the need to double the production capacity of an old liquid painting system that was by then saturated, by adding a new electrostatic powder painting system complete with pre-treatment.
By adding a new automatic powder painting system, the customer was able to:
- double the total production capacity;
- increase the painting quality of key components;
- reduce the environmental impact caused by solvents and the disposal of saturated paints and filters.
But among the requirements, the main challenge was being able to provide a non-stop (always on) system while reducing the system’s energy cost…
The high production rate non-stop powder coating system
The requirement was to have a new system for powder coating the components it produces in-house and markets under its own brand name. The powder coatings used are of a special type that withstands high temperatures, as the products it manufactures relate to the field of thermal heating.
The system also had to guarantee a high production rate so as not to be immediately saturated by production, as was the case with the existing system.
The automatic powder coating system with non-stop feed made by Eurotherm consists of the following:
- 4-stage washing tunnel,
- blowing + drying,
- Wagner automatic spray booth,
- 250°C baking oven,
- automatic overhead conveyor.
The challenge: energy saving in a non-stop automatic system
Due to high production rate, the only adoptable solution was to provide an automatic powder coating system with non-stop feed, always on and without doors.
This type of systems, although providing a very high production rate with regard to the complete coating cycle, is generally not equipped with active energy saving systems; the system is also designed to be constantly on, with consequent non-stop feeding of the parts to be coated.
We therefore came up with a technological solution to contain the energy wastage that afflicts this specific type of system, a critical issue and one that lies mainly in the two high-temperature drying and baking tunnels which, for this type of application, are always switched on and without barriers to contain the heat entering and leaving the silhouettes of the pieces.
To such a challenge, Eurotherm responded by designing a dual heat recovery system, with the aim of taking the waste heat from the ovens to heat the degreasing liquid in the washing tunnel and heat the working environment in winter.
In the first case, we have added a pre-chamber in the firing tunnel, with the dual purpose of keeping the firing inside more homogenous and taking advantage of the dispersed heat, to channel it, via a by-pass system, partly towards the heat recovery device which in turn heats the degreasing liquid and partly back into the firing chamber itself.
In addition, since a vent is always required on all drying and baking tunnels to evacuate the gases formed during the heating and baking of the parts, but which is also a source of heat loss, we have connected another heat recovery device at the outlet of both of these vents for heating the working environment in winter.
The result of Eurotherm’s challenge:
- The heat drawn from the heat recovery device is used to reheat the degreasing liquid in the washing tunnel via a water exchanger.
- A second heat exchanger has also been installed at the outlet of the heat recovery unit, which, in combination with the heat recovery unit on the oven vents, heats the working environment in winter via a thermostat.
Efficiency, high productivity, environmental requirements and energy savings: the newly developed Eurotherm painting systems meet all needs.