The case of the vanishing vacuum

I was watching a robot filling machine video when I noticed the phone was ringing. When I picked it up it was Helen. "Hi KC, I wasn't sure you were there."

"I'm all here, Helen," I told her. "I was just woolgathering. What's going down?"

"It's my labeler, KC. The vacuum holding the label fades and the label slips. Turning the air up helps for a bit but then it fades again. We are running at twice the recommended pressure and I need help."

"Be there soon," I told her and I was.

She showed me the venturi vacuum generator. It was a venturi using compressed air through a nozzle to create the vacuum. Simple, with no moving parts; they have lots of packaging applications. A sintered metal muffler on the discharge keeps the noise at safe levels.

We stopped the labeler and I got the mechanic to remove the venturi and open it up.

"Fiddlesticks on vanishing vacuum, Helen. There's your problem!" I exclaimed. The inside of the venturi was full of dust restricting the free flow of air. "It looks like the venturi is accumulating ambient dust through the vacuum port and clogging. It's an easy fix. First, clean the venturi and that will hold you for a while. The real fix is a solenoid valve to turn the venturi off when not needed. That will prevent most of this atmospheric dust. Change the muffler in case it is clogged too."

Venturis are fool-resistant but nothing is ever foolproof.