problems with glue pumps

[lhall]

I'm hoping someone can help me out. We run a Krones Rotina cold-glue labeler, and lately I have been having a heck of a time trying to keep the glue pump running. The glue pump is an air operated piston pump, and it will run fine for a while, and then quits moving. It is not locked up, since we can move the piston up and down easily by hand. If we transfer the pump into a bucket of hot water, turn off the air and manually move the piston up and down to work the pump, then after a few minutes it will begin to work well again. We'll start up the labeller again only to have this happen again after about twenty minutes.

I've rebuilt the pump, replaced the air controls. We have good cool air, with a moisture seperator and buffer tank before the bottling line.

To keep it running nowadays, I have to stand by the machine and pour hot water over the pump whenever it begins to slow down.

Has anyone had this problem with Krones glue pumps? The Krones people can't tell me what to do, and I've replaced everything short of buying a new pump (they are not cheap). Are there any other pumps you can recommend? Or a better way than using a pump to get the glue to the labeller?

[Alex T]

hi,

we had problems like this in brewery where i previously worked. we ended up replacing the air block that fits to the side of the glue pump and all started working again. our packaging man subsequently took the old air valve apart, cleaned all of the cams, but back together again and it worked fine - so maybe just strip down and clean?

alex

[I.D. Rinks]

Lubrication - 3 drops of light oil in the air line for every use...

[bawi]

Gravity Flow Option

Since you are on a Krones Rotina, it may be possible to use a gravity flow system for your glue by mounting the glue dispension system higher than the labeler and regulating the flow. The air system driven pump is an expensive option to accomplish the objectives of getting the glue down to the labeler in the quantities it requires. Just an idea.

[lhall]

Well, replacing the air block did not help. But replacing all of the internal seals for the pump itself fixed the problem. I'm not sure why running hot water over the pump helped for a while.

[matt]

After the fact.
But the warm water reduces the viscosity of the glue and then the pump(with worn seals) may work.

I would still check with the glue supplier for operating temps for your glue.
If you are in a cold part of the world, setting the tub of glue in warm water may help glue flow better.