sm74/5 blanket wash

[bgfx]

our blanket wash is not working properly it won't wash the blankets and will only do two back cylinders at a time we think it may be a air preasure problem, can any one tell me what the gauge right under the feeder should read when doning a blanket wash or has anyone had a simular prodlem how did you fix it

Ron

 

[junker1984]

Any combination if two? Interesting. Are you experiencing a lack of air blast at the feeder also? May not notice it much, but if so, I'd check the compressor filters , vanes, air line going to manometer, if its the original black spiral stuff, they crack and you'll notice pressure drops.

 

[bgfx]

yes we have noticed a drop in air blast, at the moment we have the airline bypassing the three way valve and running direct to feeder head
we also suspect the problem to be the vanes in the pump

 

[junker1984]

If when inspecting the filters behind the cover plate you notice heavy carbon build up, it's a sign to check them. For the time being, simply replacing the filters may help the situation. Blowing them out with compressed air may help, but replacement is really the true fix. Like I mentioned, make sure the hose running to the three way doesn't have any cracks, wiggling it around whie compressor is running has often led me to find it has been the culprit, you'll hear changes in air movement.

 

[exheidmech]

With the older style blanket washers on SM74, the bladder style there are a few pretty common problems. First make sure all bladders are in good shape. Easiest way to check this is to have the washers connected via pneumatic line and sit them on the catwalk. Make sure all washers have the towel rolls removed. In the manual washup screen inflate all bladders at once and start the main compressor. Regulator under the feed board should read between .5 and .6 bar. Next check to make sure that each washer bladder is inflating properly with no air leaks. Once you have confirmed correct bladder pressure and no air leaks, install all washers without towel rolls. Ink up each unit and drop form rollers to plate inking up plate completly. Manually back off back cylinder pressure completely. Manually put each unit on impression which will ink up blanket cylinders completely. Once all blankets are inked up completely you will need to work on each unit one at a time. Inch 1st unit until blanket gap is facing away from the blanket washer. Manually inflate 1st unit blanket washer only making sure you start the main compressor. Leave the blanket washer inflated for approx 15 seconds and then deflate. Inch the machine until you can see the stripe left from the washer. You should see a 3 mm stripe. Next check is the condition of the spray tubes. manually purge the water and confirm visually that each nozzel is spraying. Do the same with the solvant nozzels. Best way to clean nozzels is with gas welding tip cleaning files. Follow these steps and I promise you that your washers will all work like new.

 

[bgfx]

Just checked and we are only getting .2 bar on the regulator is ther an adjustment for this
or do I need to replace vanes in the pump (Rietschie Druvac) is this something that we can do ourself or should I send it out to be done

 

[junker1984]

Replacing vanes is relatively easy. Remove the (5 or 6) 5mm Allen caps from the end cap side opposite the motor. End cap slides off locating pins. Pay attention to direction of bevel. Do yourself a favor before buying vanes though. Do whatever is necessary to verify you don't have a cracked hose, the intake port above the removable cover is free of blockage and you have installed new filters. Don't assume blowing them out with compressed air has cleared them. They're paper and are meant to be replaced regularly.

 

[junker1984]

Bevel (or radius) on the vanes, not the end cap

 

[bgfx]

just measured the vanes they are 44.5mm the operating instructions say the must be greater than 38mm not sure if I should replace, removed air filters and ran pump just to see if that helped no difference, we replaced the air line awhile ago and its about a meter to long not sure if this could affect

 

[exheidmech]

My bet is there is a air leak in the hose going from the compressor to the regulator. Once you have confirmed that the hose connecting the compressor to the regulator is ok and you still have less than .55 bar at the regulator, this can be adjusted by the screw on the operator side of the regulator. Loosen the 13mm nut and turn the flat head screw in/out until you get .55 bar and then retighten the nut.

 

[bgfx]

press operator away for a few days, will try this when he returns will let you know how it go's

 

[bgfx]

well done exheidmech, making that adjustment worked a treat we also found a leak in the air hose from the 3 way valve to feeder head so we now have blanket wash plus heaps of air at the feeder, you have made my operator very happy, not so happy with our local Heidelberg guys who we called in a few years ago they spent nearly a day and could not find the fault
thanks again
Ron