Help,problem with the injector powder.

[Kirill]

Hello HVOF experts.
At our production we use the gun Sulzer Metco DJ2700 modification dj9a. I'm just starting to understand its structure. I tried to put the powder (Ni- base, Cu- 43.5%, Fe- 2.96%, B- 1.3%) size of 0.063, but something went wrong. There was clogged powder injector art.no. 1001860. When purchasing a gun from an authorized vendor, we provide drawings for the production of their own, broken parts. But it so happened that almost all the drawings were lost. Question number one, for some reason, it could cause blockages? Question number 2 where to find a drawing of the product: powder injector dj8-9 1001860. It so happened that my fault, there was a breakdown of equipment, and the cost deducted from the damage of my money. Thanks in advance.

[Vadim Verlotski]

Hi Kirill,

I will try to answer your first question. The powder that you use is lightly fusible. If the parameters selected by the flame is too "hot", the powder particles can melt while in the nozzle. In this case, droplets of melt necessarily adhere to the inner surface of the nozzle and clog it. It is necessary to choose such a "cold" parameters of the flame to the powder particles do not melt. To reduce the temperature of the particles while retaining their high velocity is necessary to use high pressure of powder gas (nitrogen).

Regards

[Kirill]

Thanks for the reply, Vadim.

The fuel we use 85% of propane, the pressure in the system before the start of 6.2 bar. At the time of spraying operating pressure of about 5 bar. Oxygen is supplied under pressure 10.2 bar. Operating pressure of oxygen 6-8bar. Show you how to change the settings that would lower the temperature? without loss of particle velocity. What should be the operating modes?

[Vadim Verlotski]

Thanks for the reply, Vadim.

The fuel we use 85% of propane, the pressure in the system before the start of 6.2 bar. At the time of spraying operating pressure of about 5 bar. Oxygen is supplied under pressure 10.2 bar. Operating pressure of oxygen 6-8bar. Show you how to change the settings that would lower the temperature? without loss of particle velocity. What should be the operating modes?

Hi Kirill,
The decisive factor is Carrier Gas. You shall set it to maximum flow. One could also reduce propane and oxygen, but that leads to reduction of the kinetic energy of the particles.

[loriolo]

Hi Kirill
I can surely say you, that this problem is normal in all DJ torch, so, you must clean or change barrel every 30 minutes, otherwise update a Woka star or Woka jet or JP500 torch, that performs better