Once the Flume catheter tip is inserted through the urethra to the bladder, the balloon that inflates is designed to envelop the tip, with the drainage ports inset low at the base of the balloon.
Here's how the new Flume design tackles the known problems of the Foley
Here's a video of the Flume catheter being inflated...
What you can see is the balloon inflating over the top of the tip and the protected route to the drainage ports set low at the base of the balloon.
Rotational view of inflated balloon
And here you can see a rotation of the inflated balloon, showing how it envelops the catheter tip as well as the protected access to the two drainage ports on opposite sides.
Folded form for insertion
The soft balloon material is folded over a tapered tip both to give a good profile for insertion and to leave the drainage ports clear.
Draining of Flume catheter
Here, the Flume catheter has been placed in a soft silicone bladder model with 6mm diameter urethral component. The water is passing through the drainage ports and out of the end of the catheter tube just visible below. At the end there is very limited residual water left in the ‘bladder’.