QMDI Classic Vacuum Pump

Discussion in 'DI Presses' started by Richard_Hardin, Oct 31, 2017.

  1. Richard_Hardin

    Richard_Hardin Member

    Joined:
    Jul 2015
    Messages:
    20
    Location:
    Eureka, CA
    On our QMDI Classic, we have been noticing a decrease in blast air on the feeder. I checked the vacuum pump and there was air coming out of the pressure release valve on the pump. I went ahead and pulled off the front plate and pulled out the two filters. The right filter is filled with a black powder and smells burnt. I haven't pulled anything else from the pump yet, but I didn't see any stuck veins in the pump, however I need to find the cause of burnt substance in the filter and as to why air was coming from the pressure release. I have attached a couple of images. I am not experienced with these pumps, but I am wondering what it is supposed to look like in there. The cylinder that the veins are nested it, is it supposed to be that off center looking from the rest of the pump?
     

    Attached Files:

  2. Paul Cavanaugh

    Paul Cavanaugh Senior Member

    Joined:
    Dec 2009
    Messages:
    628
    Location:
    Kennesaw, GA
    It is not unusual for the filter to look that way. It is just graphite from the vanes of the pump. The pump is configured correctly , as the shaft turns the vanes slide out and run against the wall of the compressor, this forces the air towards the exhaust side of the pump, the vanes retract back into their slots as they rotate to start the process all over again. As they pass the vacuum side they pull air in and extend to push it to the exhaust side. In most instances where vacuum is not sufficient, I have found the air lines have collapsed due to the heat the pump produces. In some instances the air lines have actually blown off the fittings.
     
  3. Richard_Hardin

    Richard_Hardin Member

    Joined:
    Jul 2015
    Messages:
    20
    Location:
    Eureka, CA
    Thanks for the help and explaining how it works. I do have a new set of veins and a new filter so I am going to go ahead and toss those in and see if that could clear the issue. It sounds like the air coming from the pressure release valve is just a clogged filter with a bunch of graphite in it. I wasn't sure if that black powder was from something else like a seal of some sorts so i'm glad its just from the veins and that I don't need to pull the rest of the pump apart! I will post more info here if this issue hasn't been resolved.
     

  4. augustov

    augustov Senior Member

    Joined:
    Aug 2011
    Messages:
    146
    Location:
    Colombia
    Yes my friend the graphite block is necesary stay complety for make more suction and air blasting, the filter, well is easy to find, not necesary can be the original, i used some like equal but not original and work nice, no even you can find parts in anye where, sometime you need solved with solution near to you, make sure that not move the cap for filter, is different.
     
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