The Airtorch® type of very high temperature forced air convection system employ a special class of elements to heat ambient air and to direct the heated air towards at a surface (or coatings) or into a chamber. The Airtorch® is constructed with very special ceramics, intermetallics and metals – special material combinations for the system to perform with the highest power-conversion efficiency. Depending on the model, the Airtorch® system can achieve temperatures up to 1200°C (~2192°F) with infinitely variable volume flow rates, no noise, low pressure drops, and no harmful emissions; thus providing for a beneficial new method of heating with modern controls. MHI Airtorch® applications are seen in drying electrical varnish, coatings, powder spray heating, weld pre-heating, die heating, rubber roller die heating, plastic softening prior to forming, drying motor parts, removing moisture, expansion fitting, preheating and heating molds, curing, prosthetics, heat shrinking, compression molding, flock setting, curing catalysts drying slurries, freeze drying, improving ink print finish, finishing mirror drying, latex, heating adhesives, and general heating of chambers as discussed below with the schematics. The flow-graphs may be used for all MHI Airtorch® models except for the very low KW such a LTA750-01 or 2 KW models.
Augmentation Use for improved uniformity and additional power: Add an Airtorch® to existing or new chamber for powder, liquid finishing and general process augmentation. Add to continuous furnaces for wood conditioning, metal finishing and forming. The Return on Investment (ROI) from an Airtorch®installation is normally very high. The Airtorch® models often qualify for the MHI-Never-Down program. Several Airtorch® models are available. The three broad application scenarios are diagrammatically captured below.
The Airtorch® convective system uses a special class of elements to heat ambient air and direct that heated air towards a surface or into a chamber. Depending on the model, the Airtorch® system can achieve temperatures ranging from room temperature to 1100-1200°C (~2200°F) with infinitely variable volume flow rates and no harmful emissions, providing a beneficial new method of heating with modern controls.
MHI Airtorch® applications are in drying electrical varnish, weld pre-heating, die heating, plastic softening prior to forming, drying motor parts, removing moisture, expansion fitting, combustion,, simulation preheating and heating molds, curing, prosthetics, heat shrinking, compression molding, flock setting, curing catalysts drying slurries, freeze drying, improving ink print finish, finishing mirror drying, latex, heating adhesives, and general heating of chambers as shown below. Add to chambers for powder, liquid finishing. Add to continuous furnaces for wood conditioning, metal finishing and forming. Very smalll but finite temperature drop is experienced when directing Airtorch® flow with insulated piping because of the high velocity.
For impingement type of applications the DPF’s offer very superior value.
A good rule of thumb for augmenting uniformity in an existing furnace with an Airtorch™ add-on is to choose a Aitroch power with at least 30% of the original furnace power. This may not be enough if a temperature increase is also sought.
When planning to extend the Airtorch exit piping, please note that well insulated pipes will drop the temperature only very little as the exit velocity is m/s. Please contact MHI when required. A helpful but very rough rule of thumb may be about 50°C-100°C/m drop for good internal pipe insulation. A good pipe insulation is specific to the insulation and whether the pipe is internally or externally insulated. The MHI industry standard is about a 1-2″ thick insulation.
The use of Airtorches™ may be classified into 3 major categories schematically drawn below
Example of Use to Augemt an Existing Furnace Installations for Improved Power and Iniformity.
Example of a 4kW Airtorch™ augmentaion application schematically shown below. In this application, many complex shaped rods are to be heated uniformly. The heat-treater reported that the rods were not uniformly heated in his existing radiant heat furnace. MHI proposed a add-on to his existing furnace with a system of airtorches which then greatly impacted the uniformity and reduced the total energy consumed. More Green Installation and more Profits to the user. Impove oven performances and eliminate bad emissions.
A common error is the preference to have hot air circulator but there is minimal advantage of that compared to
using and letting the hot air go compared to using energy and equipment to re-circulate hot air for small ovens.
A uniform surface heating retrofit example and continuous oven example is illustrated below.
As a rule of thumb an Airtorch power of 0.3 the furnace power is employed when designing for better uniformity.
Heating: Create a convective cavity around the assembly using two 4kW Airtorch™ units. Fixture Airtorches™ behind mold and electrodes at angles to create air movement. This should improve the overall heating of the mold.
Insulation: The assembly is surrounded by refractory blankets (all 5 sides) to retain as much heat inside as possible. Blankets can be supplied by MHI at customer’s request.
Solution: By supplementing the existing electrodes with the Airtorch™ and blankets, the watt density is increased on the mold thus reducing the workload of the existing electrodes which should improve performance and life. Other results include an increase of uniformity across the mold surface. Call MHI for more information.
With its variable volume flow rate and power adjustability, the Airtorch® can be set up to perform at any condition of flow-temperature under the curve. Such features offer the user maximum flexibility when applying the Airtorch® technology to your specific heating application.Easy to use selection and design page.