Lately, I've had a rash of cement balls getting by the mixer drivers.  Today, pumping at about 1/3 volume to keep the 3" hose at a steady flow so it didn't spatter and the flow simply stops, I cut the pump, but enough pressure had built that it released a moment later - WHOOSH!!  Thankfully, the hoseman had a good grip throughout the wall pour, I asked if we were good to go, he said yes, so away we went.  I had a chat with the RM driver about watching for them coming down his chute.

I've had drivers push them through the grate on purpose - WTF???

Try welding horizontal bars on the hopper grate (just make sure your vibrator is in good working order). After putting bars on ours I would estimate that plugging through 3" line has been reduced by about 80%, most of the dry balls you speak of will be broken up from the vibrating action of the double grate. It's probably one of the best low cost mods. we have done to our machines.

You don't then pump fibreconcrete? I bet it won't go throught that grill. And stiff concrete is surely building up to that. Better option IMHO, is to make removable lightweight grill, for example from 6mm steelbars. If you appear having blocks, then put it on original grill and problem solved.

Pumpjockey, just asking , was you using a reduction hose or steel reducers, I know we have issues like this constantly that's why those red. hoses are locked up and cannot be used.

Yes, using 2 long reducers from 5 to 4 and 4 to 3, I've given up on the short reducers.

Great pic 16 cell. I would prefer a removable add-on. The vibrator works great.

Don't pressure out a plug, if the mud stops either swing away and try or preferably take care of it some other way. You could seriously hurt someone.

he said that he cut the pump off but it pressured out but does your vibrator work better turnedup sidedown like u have it

I have my vibe like that too. It keeps it out of harm's way. (mixer chutes)

i simply use a piece of 3" x 6" wire mesh cut to the size of my hopper. it keeps just about everything out that shouldn't be in there but can be easily removed if needed for a dry mix. my company owns a precast shop so thats where i got mine from but i'm sure that some of this stuff would be easy to track down.