Arecent visit to South Africa by export manager for SAIMA, Salvatore Antonucci, spent some time explaining the move on a global basis to introduce their retro-fit endothermic panels which produce amazing paint curing when used with waterborne refinish paint products which are now common in use. This is in a drive to drastically reduce the bake cycle when using diesel of LPG types of products which continue to escalate on a regular basis.

Automotive Refinisher takes a look at some of the features that endothermic curing can achieve according to SAIMA, who have been ramping up their retro fit spraybooth fitments in the last 10 years with this new technology on the spray booth of the future.

Q How does the Endothermic spraybooth represent a real breakthrough in the world of painting booths?

AThe Endothermic spraybooth does not need any burner nor any sort of thermal power plant. Those parts become unnecessary since there is no need for heating all of the air that gets inside the booth: the surface to bake is heated by convection by means of the radiant panels positioned on the booth walls.

The various processing stages and removal necessary airflow is ensured to the system by a single outdoor unit named “Central Air Treatment” (CTA). Inside the CTA are placed both one in-take and one out-take turbo ventilators and two 11kW motors. Each motor is obviously coupled to its turbo ventilator, so the CTA is a self-standing and independent unit, making it possible to save much space to its vertical development, instead of the widespread building way.

Q Tell us how is the heat diffused without a burner inside the spraybooth?

AThe heat is diffused through the radiant panels fixed on the walls; the shape to be formed is heated by radiation. The panels are made with a high technology material: with low energy absorption we achieve a diffused radiation result.

Q Depending on the heating lamps experience, is the power consumption equally high?

ANo, it is not. Thanks to this innovative technology, the booth power consumption, during painting and/or drying phases, is lower than 60kW. The installed power includes the simultaneous operation of engines, lights and radiating panels during all of the processing stages. The absorption, however, is considerably lower than the installed capacity thanks to the irradiation control system that cyclically turns the panels on and off.

Q Is it possible to control the temperature both on the source of irradiation and on the work piece?

AAt any time the operating temperature is under control both on the panel (in the surface transmitting the heat) by means of appropriate probes inserted inside it, and on the template, thanks to a special gun provided.

Q Is there a source of risk to have heated panels on the walls during the painting phase?

AThere is no danger in the temperature lead to the panels during the painting phase, always assuming that the necessary conditions of heat exchange are kept, because the panels will while they work never exceed the temperature of 140º. Nevertheless we know that paint becomes dangerous when in contact with a 400º and above heat surface, just like it happens with the common lamps working at temperatures well above the indicated threshold.

Q During the painting phase is it necessary to use special operating procedures on panels?

AThanks to the unique SAIMA technology and materials, the temperature of the panels at the maximum operating temperature is expected to be compatible with the common use electrostatic protective aprons and any overspray on the walls may be cleaned with an ordinary solvent soaked cloth, when the panel is cold and the paint has gone dry.

Q Tell us about colder conditions, like winter and the effect it has on endothermic drying.

AIn this conventional operation case, the system works by heating the air and the heat is transmitted to the shape in the cab thanks to the convection effect.

So the outside temperature is very important to achieve the temperatures necessary to perform various processing stages. In the Endothermic spraybooth, the heat is transmitted with a radiation process, so the to-dry piece is heated directly by heat-waves. In addition, these are the reasons why the air that is introduced into the booth does not cause any change in the process:

  1. a) the temperature rise due to the compression that the air undergoes when pushed by the fan towards the interior of the booth;
  2. b) 0.3 m/s air speed, used only during the painting phase, is not perceptible by humans;
  3. c) the convection heat transmission is an inefficient system and therefore has a low cooling capacity too.

Q How do you manage air flows with an endothermic spraybooth?

AThis is the only existing system where you can manage, as independent variables, the various processing stages, the heat transmission (which is necessary to perform coating and drying) and the air flow rate (which is necessary for over-spray abatement and solvent-emissions removal). Moreover, the adoption of a standby device allows, thanks to the inverters varying the number of revolutions of the fan motors, to adjust the airflow rate to the best rates during every single working phase to reduce the power absorption. During the drying phase more saving is provided by the need of performing just a motor (CTA) cycle of one minute every 10 operating minutes.

Q What are the total cost savings after a traditional type of system in real money?

AThis question allows us to articulate the answer in three key points: a) Reduction of the processing time: if an average masking, coating, drying and cooling cycle takes about 120 minutes, with the endothermic spraybooth we are able to reduce the total processing time to about 15 to 20 minutes. It is important to focus on the fact that the time reduction is obtained not only during the drying stage, but during the phases when the operator works inside the booth. The drying time reduction results in lower labour costs.

  1. b) The operational cost saving is the key evolution step enabled by endothermic spraybooths.
  2. c) Building cost savings: since there is no need for a generator, you will avoid undergoing any administrative and supervisory surveys, saving lots of money and time, as well as needing a smaller CTA unit for the booth to work properly.

It is important to emphasise you will not need any thermal power station, without any connected loss of money and time.