I want to pump very heavy grease along a tube that could be around 10mm inside diameter. The grease would be in a tube about 100mm diameter (a plastic drainpipe actually) and I hope to pressurise that by winding a piston down on a thread. I'll have a valve at the end of the pipe to control the flow. It would be bit like an ordinary grease gun on a large scale. The grease merely has to dribble out the end, so no pressure is needed after that. So, will the grease move in the small tube before the large tube bursts?
Ideally I would like to pump the grease at a variable rate using a rotary pump, but that looks a bit hard to make.