ok ladies and gents

This is my first post on this wonderful forum so please be gentle

I have an existing system which transports ready-mixed mortar (wet)

the unit is split into compartments for multi-drops at different sites

the main body has a central shaft with blades in each compartment to allow for a quick mix before discharge

at the moment we have a Ø130mm tubular shaft running through seal housings in the wall of each compartment

these housings are designed to use compression packing which we purchase from one of the main suppliers

the shaft is in-machined and each stuffing box has a greasing point in the middle to allow periodic greasing

now here's where you experts come in

the current set-up will work for a short time and then they start to weep

I have had our design checked by the seal manufacturer and it does check out OK but they cant suggest any alternatives

So any thoughts as to what else we could look at using given the extreme conditions the mortar gives ■