When I said like E-wall, it has a same concept, but E-wall can't turn anything that it's touching invisible. PHTM can. Fan is good, but when you get to a turn, , the elements sometimes get stopped. Also elements change in a fan (oil to gas). Director wont do those things.
Pipe element solves the problem you described with Fan.
There ARE ways to fix the problems you're explaining without adding new elements. Making them invisible is something that would require a new one, but like with oil turning into gas, there's always a way to fix stuff like that.