Praxair powder feeder 1264 malfunction

[JeroenB]

Dear Thermal Spray experts,

We have two identical Praxair powder feeders model 1264. Both are well-maintained and are running fine for years and years. 

Last week we noticed a reduced buildup on one of our HVOF installations. We changed powder feeders and the problem was solved.

We compared both powder feeders on one product and the buildup was only have with the "problematic" powder feeder. The powder consumption was also half so it is a feed problem. 

We have disassembled the powder feeder already twice and checked all items below:
1. We changed the slotted disc for a new one
2. We checked that all nitrogen & powder channels are free
3. We checked the RPM settings of the machine with the actual revolutions
4. We changed all wear parts with new ones

The problem still remains... Could you please share problems that you have had with your powder feeder installations so that I could find some inspiration as to where the problem might occur?

Thank you,

Jeroen Belis

[dawgpound]

Have you leak checked the feeder?

If you remove the powder hose from the torch and instead feed directly into an empty bottle for x amount of time, do you collect the same amount of powder as you would with the good feeder?
If you start with 2 kg in the hopper and do the above test, then measure the powder weight left in the hopper/barrel afterward, how much is it?(and how much is it on the good feeder?)

Is it the same powder carrier flowmeter used with each hopper, or does each hopper have its own flowmeter? If you use different flowmeters, are you using the same mass flow rates between the two?

Do you use a tamper assembly?