Problem with suction & blowers on DI Plus

Hi Guys

I am having a problem with the suction and blowers on my DI. I am running a 135gsm Gloss stock and have to set my blower & suction dials on 9 to get the sheets to feed. When i run 300gsm Gloss i set the dials on 10. I have checked the Pressure guages on the compressor they are OK. I have had my Tech check the piping system for cracks and leaks but have not found any.
I have had my operator take a pin and open all the holes on the blowers to ensure there is not blockages. This helped the blowers a little bit but.

Does anyone have any ideas what the problem could be.

Quinton - South Africa

 

Have a look at the 3 / 2 way valve, strip it down and give it a clean, there is a video on U Tube.

Regards.

 

Hi Quinton,
You are probably mixing three things together, they have nothing common.
1.Gauge on the compressor under the stairs, shows the pressure in the pneumatic system
and has nothing to do with the blow & suction air.
2. I guess that "take a pin and open all the holes on the blowers", means to clean the Technotrans ribs.
It would also not help you in your problem.
3. The blow and suction compressor is located under the feeder and has 3 filter, you have probably never changed them or at least cleaned them. Pls. do it.
Recently I had to open the turbine of this compressor, the dirt caused by the lack of service stopped the carbon blades to move.
Could be that your the 3 / 2 way valve is dirty, but NEVER ever strip it down, until you have possibility to set it correct afterward.(You would need vacuum gauge to set it on -30mb at 298,9°).
If you don't have it, just dismantle the small cover on DS and open only 4 Phillips screws on the back side.
In this way the setting of 3/2 way valve reminds adjusted .
Good luck
Jan

 

I agree with Jan on the 3/2 valve, many people think you can just take this off and put it back on, but there is a specific time in which it must be set to activate as well as the bar pressure it must maintain at that degree. By removing it you can alter that time up to 10 degrees if you install it incorrectly. Removing the bottom of it is the best way to clean it in the press as Jan stated.

There is one other item you can check. The problem I am about to mention was rectified on the Plus version of the machine somewhere during the middle of production. The blower bar you are talking about for separating the lead edge of the sheet has two plastic ends on it. The epoxy that holds them in sometimes fails and the endpiece falls out. This causes a significant drop in air pressure and makes it difficult to feed sheets.

It is very difficult to see if the piece is missing but you can easily hear the air rushing out the end of the bar.

To repair this, if it is the issue is quite a job, requiring special gauges to install the blower back it in the correct alignment once it has been removed. I recommend a technician to come in and make the repair.

If this is not it, I would check the vanes in the compressor also as Jan stated and double check the plastic hose connection on the top of the compressor. On the Classic version of the machine the fitting the airline connected to was not barbed. When the compressor became hot from use the air hose would slip off the fitting. On the later machines the connections were barbed in order to provide a solution for this issue.

I hope this information is helpful.

 

hi mrs heidelberg how are u ?
i have a problem with mine qmdi ,the feeder does not goee up at the third line(300gsm paper or higher than this).how can i do with this. regards enri

 

Hi Enri,

You could have a issue with the pile height control.

 

Hi Guys

Thanx for the advice. I have done the following so far and have seen a few results.

1) I did the 3/2 valve as on you tube before the advice from Jan & Paul. I found that there was no lubrication
and that the black rings were starting to make scratch marks or burn marks on the inside walls.
2) I then used Jan's advice abou the Airfilters, i cleaned them out and found 1 off them did need replacing
3) I then checked the edges of the blower bar and found that the caps you are refering to had been replaced
with "Prestik or "Putty" by our technician. The reasoning for this was that it is a hell of a job to replace these
ends and "Putty" works as well. I then cleaned out his old "Putty"and filled either ends with a new batch.
This made a huge improvement. I am however concerned about his use of putty rather than the epoxy caps.

Do you think the "Putty"will work?
What do i do know that i have cleaned out the 3/2 valve.

Thanx

Quinton SOUTH AFRICA

 

I would not trust the putty.

Find a vacuum gauge as Jan mentioned and adjust the 3/2 valve until it reads -30 mb when the press is at 298.8. You can leave the 2 screws that hold it in place loose and twist it until you get the desired reading on the manometer.

 

Hello Paul,
Hope you are well.

I am having feeder problems on my QMDI plus. Unfortunately, in trying to solve the problems, I REMOVED the 3/2 Valve before I read the old posts by you and Jan about NEVER removing the 3/2 Valve.

I have cleaned out the valve and used graphite powder as a dry lubricant as per your advice on another post relating to the 3/2 Valve.

When using a vacuum gauge to reset the 3/2 valve in the correct position, do I connect the vacuum gauge to the top of the 3/2 Valve where the spiral hose normally connects?

Do I then inch the press to 298.8 degrees and set the valve in place until it reads -30mb ?

DO I need a digital vacuum gauge or will a simple automotive vacuum gauge work?

I now know that i should NOT have REMOVED the valve but unfortunately that ship has sailed. I also think that this valve has previously been removed by someone else as there is sign of wear on all the screw heads on both side covers of the valve.

My main concern now is to replace the valve in the correct position so as not to negatively affect the feeder and make my problems worse.

Please advise on what type of gauge is required for setting the valve and exactly where the gauge should be connected.

I know this is a very old post but your advice would be greatly appreciated.

Thanking you in advance.

Shawn
South Africa