Kermetico Convertible equipment offers the final solution for the HVAF vs. HVOF discussion.
You no longer need to choose between standardized HVOF equipment and our efficient HVAF processes.
You can use our Convertible HVAF & HVOF equipment spraying coatings in HVOF mode conforming to legacy HVOF standards or in an HVAF mode depositing higher-quality and less expensive coatings.
Our gas fuel HVOF allows spraying corrosion and wear resistant coatings with the best quality and cost.
Kermetico Gas-fuel High-Velocity Oxygen Fuel HVOF equipment utilizes continuous combustion of gaseous fuel, oxygen and air to generate a high velocity gas stream propelling a powder feedstock towards the surface to be coated.
The powder partially melts in the stream and deposits on the substrate.
The resulting coating has low porosity and high bond strength.
Kermetico C equipment works in HVOF mode at a particle temperature up to 1,700°C (3,100°F) and accelerates the particles sized at -45/+15 microns to 700-850 m/s (2,300-2,800 ft./sec.).
Working in High Velocity Air-Fuel mode, our Convertible equipment deposits coatings using continuous combustion of gaseous fuel and air, propelling metal or carbide powders towards the substrate.
The feedstock is being heated below its melting point, and it is much less oxidized or decomposed compared to coatings made with conventional Tafa-like HVOF equipment.
Those features allow us to spray fine particles (5-20, 15-30 microns) accelerated to over 1,000 m/s (3,280 ft./sec.)
Smaller particles are difficult to spray with conventional HVOF equipment due to the high oxidation rate and partial evaporation in the high temperature environment.
Our Convertible equipment features a lower combustion temperature even in HVOF mode.
HVAF mode excludes evaporation and minimizes oxidation, leading to excellent coating properties.
Depositing certified tungsten carbide powders with Kermetico C HVOF equipment is 100% compliant with all existing HVOF standards for tungsten carbide coating applications, from aviation-specific SAE AMS 2447, 2448, 7886 to proprietary Schlumberger, Weatherford, NOV or Siemens standards.
Our Kermetico Convertible system can be used in an existing plasma spray or HVOF booth, in a new coating shop installation or even for on-site applications.
Our HVAF-HVOF equipment includes:
As you see, there is no water chiller in setup, and the reason is – all our HVOF equipment is air-cooled.
It provides not just higher mobility and robustness – we use a greater share of the power for powder acceleration, which makes our systems more energetically efficient.
Kermetico Convertible is universal equipment so that you can use any of our spray guns with this system:
Each of our outer diameter spraying guns works in blast and spray mode, learn more about our hot grit blasting equipment here.
The Kermetico AK systems deposit the same specification coatings with a spray rate that is 5-6 times higher and at a 20-30% higher deposition efficiency, which leads to ½ of the HVOF cost and can provide a coating of higher quality when needed.
Choosing Kermetico AK, a manufacturing shop gains a 50% cost advantage over HVOF competitors and additional coating quality superiority as a bonus.
The Thermal Spray Industry uses the HVAF process infrequently because it is not consistent with most HVOF standards. (AF systems work best on fine powders, while some specifications require 15-45 or 20-53 μm powder sizes).
The Kermetico C (C for Convertible) equipment family operates in either mode.
Kermetico C uses gas fuel, oxygen and air to spray HVOF powders consistent with HVOF standards, and it works in pure HVAF mode to deposit ductile, high-hardness (1400-1600+ HV300, 6% deviation), non-permeable, smooth as-sprayed tungsten carbide coatings.
Our HVOF mode Convertible is compliant with HVOF specifications and still lets you halve operating costs. The HVAF mode offers you greater savings or allows you to create coatings with properties superior to any HVOF spec – the choice is yours.
The Kermetico convertible equipment is a unique family of HVAF&HVOF guns, designed with hot catalytic ceramic inserts, igniting the air-fuel + oxygen mixture in the combustion chamber and axial feeding of the feedstock.
The quality and efficiency of the Convertible equipment is the result of the relatively low combustion temperature of air-fuel or oxy-fuel mixtures combined with the axial injection of the feedstock through the long combustion chamber, where the low gas velocity provides sufficient time for the powder particles gradual heating.
The material’s acceleration occurs in the nozzle that has a large diameter.
The large diameter of the nozzle is needed to ensure that the nozzle walls do not interact with the powder particles, allowing the use of a nozzle that is as long as needed for feedstock acceleration, typically from 800 to over 1,000 m/s (2,600 – 3,300+ ft./sec.).
The Catalytic Insert is used in the combustion chamber to provide a broad range of stable combustion parameters.
The heating of the spray particles in the combustion chamber occurs at high pressure, where heat transfer is the most efficient.
The size of the chamber provides a long residence time for the spray particles to heat. Thus the energy transfer efficiency is increased noticeably compared to other high-velocity spraying methods, resulting in much higher spray rates.
Heating efficiency is a primary reason for the lower cost of Kermetico coatings.
The large diameter of the nozzle eliminates its length limitations, known to other guns. The spray particles can be accelerated up to the gas velocity.
Uniformity of Coating Quality:
The diameter of the spray particle jet is several times smaller than the nozzle diameter.
The influence of the nozzle walls on the spray particle velocity is negligible, providing even acceleration of the powder particles and improved consistency of the coating structure.
The C guns provide the means for the measurement of the combustion chamber pressure, which is an essential parameter of the spray process.
The data from the combustion chamber pressure transducer are used for the detection of the powder carrier gas flow during the gun ignition process.
This allows creating a safety interlock for preventing gun ignition if no flow of carrier gas was detected, preventing the possibility of a flash-back into the powder hose and flow of combustible gases into the powder feeder.
The Kermetico C Control Console consists of a Mobile Touch-Screen Industrial Tablet, a Controller, a Gun Ignition box and a set of cables and hoses.
The Mobile Touch-Screen Tablet is typically used inside the control room – on the wall (a wall-mounting bracket is provided) or laid on the table and can be easy carried around the Operator room and into the spray booth as needed.
The Controller (control cabinet) is typically placed inside the spray booth. The Tablet connects to the Controller with a 25’ (7.5 m) long cable (other cable lengths are available upon request).
The Mobile Touch-Screen Industrial Tablet is a rugged industrial computer with the Microsoft Windows CE operating system – the OS is specifically designed to work with an industrial PLC, providing better reliability than current versions of Windows 8/10 used in industrial computers for general use.
The Tablet includes a wide format touch screen (8” x 4.5”) and “Soft Touch” buttons for process control (start/stop of the gun, powder feeder, and other functions).
Its memory is expanded with an added memory card (replaceable), and an additional USB port allows for the installation of flash memory for data acquisition, quick re-installation of a lost program or future programs updates, as well as for connection to another computer or compatible electronic devices.
The Tablet has a hard-wired illuminated E-stop and the whole device with its connected cable is rated IP67 (dustproof and waterproof when submerged under water for 30 minutes).
The Tablet Touch-Screen Interface through the integrated PLC provides all of the functions necessary for the operator to control the spray gun, powder feeder, and peripheral devices that are connected to the PLC’s electronic blocks (The PLC and electronic blocks are housed in the Controller).
The Tablet program contains a number of operating windows, providing an operator interface for:
The Controller consists of two cabinets mounted together and isolated from each other:
The Controller includes:
Other functions and device settings are available upon request.
Since our incorporation in 2006, we have installed more than 60 HVAF and HVOF systems in the USA, Europe, Japan and China.
Some of the systems are at work in Universities and National Labs, but most of them are used in production thermal spray shops.
We proudly design and produce our HVAF and HVOF equipment in California and install it all over the world.
We provide thermal spray coating services for customers around the San Francisco Bay Area in California, USA.
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