The eGun™ is a liquid fuel HVOF torch that utilizes ethanol as its fuel. The eGun™ is capable of operating at combustion chamber pressures up to 13 bar (188 PSI). This is 3 to 5 bar (43 – 73 PSI) greater than conventional kerosene HP-HVOF systems. It has been shown that higher combustion chamber pressure generates higher flame velocity which in turn generates higher particle velocity. Higher particle velocity results in improved coating density and better overall coating integrity. It is also very easy to run at low flame velocity for slow and hot parameters to produce very good bonding (rough) flash coats.
Harsh starting explosions during system ignition, common with kerosene guns, is not an issue with the eGun™. Ramping-up the eGun™ System from a very slow idle mode flame to full flow is smooth and efficient.
The eGun™ schematic shows the basic design of the gun. Ethanol and oxygen are injected, mixed and atomized in the pre-chamber and then ignited. The mixture partially burns to create a fully atomized and very combustible fuel oxygen mixture. This mixture enters into the combustion chamber where efficient, stable, clean, uniform and high-pressure combustion occurs. The efficient combustion of ethanol allows for low oxygen consumption. In comparison with conventional kerosene processes, oxygen consumption is reduced by 30% to 50%. After exiting the combustion chamber the gasses pass through a carefully engineered nozzle creating a supersonic flame. At the end of the combustion chamber, the powder is radially injected into the interconnector. Optimizing powder injection reduces barrel loading in addition to creating optimal powder heating. After injection into the barrel, the powder is uniformly mixed, heated and accelerated to very high speeds.
Ethanol (C2H5OH) is a low-cost non-petroleum based fuel. It is produced globally and is easy to obtain. Ethanol is a consistent fuel providing repeatable and reproducible coatings in contrast to kerosene which consists of a varying mixture of different hydrocarbon chains. Burning ethanol results in 30% less toxic emissions than kerosene. Ethanol doesn’t have side effects related to ash formation. There is no potential for contamination of a coating by carbon even if fuel-rich mixtures are used.
Features & benefits the eGun™ - ethanol-based liquid fuel HVOF Technology
- Larger window of operation vs kerosene, thus better control over the balance between kinetic and thermal energy of the particles.
- 30%-50% reduction in oxygen usage
- Up to 50% reduction in required cooling power
- No ash formation
- Less toxic fumes
- Environmentally friendly
- Consistent fuel
- Easy smooth system starts and ramp-ups
- Ability to run very fuel-rich, creating new coatings and application opportunities
- High coating integrity and uniformity.
- Higher combustion chamber pressure results in higher particle speed.
- Coating exhibit excellent wear resistance.
- Superior microhardness compared to other thermal spray technologies
- Very high bond strengths, typically exceeding 80 MPa (10000 psi)
- High-density coatings with minimal porosity
- Low impurities and oxides levels
- Compressive stresses in the coating.
- Thick coatings, up to or exceeding 6 mm (0.25 inch) are possible
- Smooth “as-sprayed” surface finishes
- Dual-port, radially fed powder injection
- Simple design resulting in low and easy maintenance.
- Remote, Safe, Reliable and ignition design.
- Machine-mount for use with robots and traverses systems